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Combustion of natural gas and gasoline in a spark-ignition engine Baets, Jozef Eduard 1982

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COMBUSTION IN A OF NATURAL GAS SPARK-IGNITION AND GASOLINE ENGINE by JOZEF EDUARD BAETS B u r g e r l i j k w e r k t u i g k u n d i g - e l e k t r o t e c h n i s c h i n g e n i e u r R i j k s u n i v e r s i t e i t G e n t , B e l g i u m , 1979 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n THE FACULTY OF GRADUATE STUDIES (Department o f M e c h a n i c a l E n g i n e e r i n g ) We a c c e p t t h i s t h e s i s a s c o n f o r m i n g t o t h e r e q u i r e d s t a n d a r d s THE UNIVERSITY OF BRITISH A p r i l 1982 (c) J o z e f E d u a r d B a e t s , COLUMBIA 1982 In presenting t h i s thesis i n p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t f r e e l y available for reference and study. I further agree that permission for extensive copying of t h i s thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. I t i s understood that copying or publication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of Mechanical Engineering The University of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date A p r i l 28, 1982 DE-6 (3/81) i i ABSTRACT T h i s t h e s i s p r e s e n t s t h e r e s u l t s of an i n v e s t i g a t i o n of t h e d i f f e r e n c e s i n c o m b u s t i o n between g a s o l i n e and n a t u r a l gas i n a s p a r k - i g n i t i o n e n g i n e . C o m b u s t i o n d e v e l o p m e n t i s i n f l u e n c e d by c a l o r i f i c v a l u e , s p e c i f i c h e a t , f l a m e s p e e d and t h e g a s e o u s o r l i q u i d s t a t e of t h e f u e l . S i m p l e s i m u l a t i o n p r o g r a m s were s e t up t o i n v e s t i g a t e t h e e f f e c t s of low f l a m e s p e e d and h i g h e r s p e c i f i c h e a t of t h e f u e l - a i r m i x t u r e . A c t u a l p e r f o r m a n c e was measured on a s i n g l e c y l i n d e r t e s t e n g i n e u s i n g i o n i z a t i o n p r o b e s as f l a m e d e t e c t o r s and a p r e s s u r e p i c k - u p . The e x p e r i m e n t a l . r e s u l t s show t h a t l o n g e r i g n i t i o n d e l a y and l i m i t e d f l a m e s p e e d a t h i g h p r e s s u r e and t e m p e r a t u r e a r e t h e main r e a s o n s for' t h e power l o s s of n a t u r a l gas a t h i g h e n g i n e s p e e d ; t h i s i s i n a d d i t i o n t o t h e b a s i c l o s s due t o t h e r e p l a c e m e n t of a i r by g a s e o u s f u e l i n t h e c y l i n d e r . From c a l c u l a t i o n s , i t was l e a r n e d t h a t s p e c i f i c h e a t and d i s s o c i a t i o n d i f f e r e n c e s had l i t t l e e f f e c t on power. i i i TABLE OF CONTENTS A b s t r a c t i i L i s t o f F i g u r e s v i A cknowledgements i x N o m e n c l a t u r e x I . I n t r o d u c t i o n ... 1 1.1 M a t h e m a t i c a l s i m u l a t i o n o f e n g i n e p e r f o r m a n c e .... 2 1.2 E n g i n e e x p e r i m e n t s 3 I I . E n g i n e P a r a m e t e r s 5 11.1 I n t r o d u c t i o n .... 5 11.2 I n d e p e n d e n t v a r i a b l e s 5 a) t h r o t t l e p o s i t i o n .... 5 b) a i r f u e l r a t i o 6 c ) i g n i t i o n t i m i n g 6 d) e n g i n e s p e e d 6 11.3 D e p e n d e n t v a r i a b l e s 7 a) work and power 7 b) f u e l economy 7 c ) c o m b u s t i o n 8 I I I . L i t e r a t u r e Review 11 111.1 C o m b u s t i o n i n s p a r k - i g n i t i o n e n g i n e s 11 a) c y c l e - t o - c y c l e v a r i a t i o n 11 b) c y c l e c a l c u l a t i o n s 14 111.2 Methane r e s e a r c h 14 a) methane c o m b u s t i o n i n e n g i n e s 15 b) f l a m e s p e e d 16 IV. E n g i n e P e r f o r m a n c e C a l c u l a t i o n 18 i v IV. 1 C a l o r i f i c v a l u e of t h e f u e l 18 IV.2 Gas c o m p o s i t i o n 20 IV. 3 Flame speed 22 a) o b j e c t i v e 22 b) method 22 c) r e s u l t s 24 V. E x p e r i m e n t a l D e s i g n 31 V. l O b j e c t i v e 31 a) i o n i z a t i o n p r o b e s 31 b) p r e s s u r e measurements -32 V.2 A p p a r a t u s 32 a ) e n g i n e 32 b) e n g i n e i n s t r u m e n t a t i o n 33 c) d a t a a c q u i s i t i o n s y s t e m 35 V.3 T e s t c o n d i t i o n s 36 a) i n d e p e n d e n t p a r a m e t e r s e t t i n g s 36 b) measured v a l u e s 37 c) t e s t c o n d i t i o n s ., 38 VI . D a t a A n a l y s i s 43 VI . 1 O b j e c t i v e 43 VI . 2 D a t a r e c o r d i n g and d i g i t i z i n g 43 VI .3 S t a t i s t i c a l a n a l y s i s 45 a) c a l c u l a t e d v a r i a b l e s 45 b) s t a t i s i c a l p a r a m e t e r s 46 c) a n a l y s i s r e s u l t s 49 V I I . D i s c u s s i o n of E x p e r i m e n t a l R e s u l t s 52 V I I . 1 I n t r o d u c t i o n 52 a) r e l e v a n t i n f o r m a t i o n d e s c r i p t i o n 52 V b) i n f o r m a t i o n s o u r c e 52 V I I . 2 I o n i z a t i o n p r o b e s 53 a) i g n i t i o n d e l a y 53 b) f l a m e speed 54 V I I . 3 P r e s s u r e measurements 55 a) e n g i n e work 55 b) peak p r e s s u r e 56 c) a r r i v a l t i m e of peak p r e s s u r e 56 V I I I . C o n c l u s i o n s and Recommendations 62 V I I I . 1 G e n e r a l t h e s i s o v e r v i e w 62 V I I I . 2 M a j o r r e s u l t s 63 a) e n g i n e power 63 b) c y c l e - t o - c y c l e v a r i a t i o n 63 c) p r e s s u r e d e v e l o p m e n t 64 d) f l a m e p r o p a g a t i o n 65 VI11.3 Recommendations 65 a) equipment improvement 65 b) r e s e a r c h f i e l d • 66 R e f e r e n c e s 67 A p p e n d i x A. C a l o r i f i c c a l c u l a t i o n s 72 A p p e n d i x B. Gas c o m p o s i t i o n c a l c u l a t i o n s 74 A p p e n d i x C. Flame speed c a l c u l a t i o n s 76 A p p e n d i x D. D a t a a n a l y s i s p r o g r a m 81 A p p e n d i x E. D i s t r i b u t i o n and c o r r e l a t i o n of s i g n a l s 85 A p p e n d i x F. D a t a a n a l y s i s r e s u l t s 95 A p p e n d i x G. D a t a a c q u i s i t i o n s y s t e m c i r c u i t d r a w i n g s 132 v i LIST OF FIGURES Fig.1 p-V diagram and engine l o s s e s 9 Fig.2 dependence of f u e l consumption on spark timing and a i r - f u e l r a t i o 9 Fig.3 combustion stages in a SI engine 9 Fig.4 peak pressure and power as f u n c t i o n of i g n i t i o n advance 10 Fig.5 flame propagation stages < 23 Fig.6 s p e c i f i c f u e l consumption' 29 Fig.7 i n d i c a t e d mean e f f e c t i v e pressure 29 Fig.8 optimal i g n i t i o n timing 29 F i g . 9 s i m u l a t i o n of expansion r a t i o ( s i d e spark plug) . 30 Fig.10 s i m u l a t i o n of expansion r a t i o ( c e n t r a l spark plug) ' 30 Fig.11 i o n i z a t i o n probe p r i n c i p l e 38 Fig.12 Kohler K361 engine 40 F i g . 13 c y l i n d e r head 40 Fig.14 data a c q u i s i t i o n system 41 Fig.15 ion probe s i g n a l s 42 Fig.16 peak pressure s i g n a l s 42 Fig.17 c y l i n d e r pressure development 42 Fig.18 pressure-volume diagram 42 Fig.19 experiment M1.L 50 Fig.20 experiment G2.9 51 Fig.21 flame t r a v e l from spark plug to probe 1 59 Fig.22 flame t r a v e l time between probe 1 and 2 59 Fig.23 flame t r a v e l time between probe 2 and 3 59 v i i F i g . 2 4 i n d i c a t e d mean e f f e c t i v e p r e s s u r e f o r t o t a l e n g i n e c y c l e 60 F i g . 2 5 peak p r e s s u r e 60 F i g . 2 6 s t a n d a r d d e v i a t i o n on peak p r e s s u r e 60 F i g . 2 7 a r r i v a l t i m e o f t h e peak p r e s s u r e 61 F i g . 2 8 c y l i n d e r volume e x p a n s i o n n e a r TDC 61 F i g . 2 9 1^  d i s t r i b u t i o n 85 F i g . 3 0 I 2 d i s t r i b u t i o n 85 F i g . 3 1 I 3 d i s t r i b u t i o n 86 F i g . 3 2 T d i s t r i b u t i o n 86 * PP F i g . 3 3 p d i s t r i b u t i o n 87 p F i g . 3 4 imep^^ d i s t r i b u t i o n 87 F i g . 3 5 imePp d i s t r i b u t i o n 88 F i g . 3 6 I d i s t r i b u t i o n 88 F i g . 3 7 I" . d i s t r i b u t i o n 89 y 23 F i g . 3 8 c o r r e l a t i o n between I and I 89 F i q . 3 9 c o r r e l a t i o n between I and I 90 y 2 3 F i g . 4 0 c o r r e l a t i o n between I and p 90 1 P F i g . 4 1 c o r r e l a t i o n between I and p 91 2 P F i g . 4 2 c o r r e l a t i o n between I and p 91 F i g . 4 3 c o r r e l a t i o n between I and p 92 12 p F i g . 4 4 c o r r e l a t i o n between I and p 92 23 p F i g . 4 5 c o r r e l a t i o n between T and p f o r PP P methane a t \ = 1 . 1 93 F i g . 4 6 c o r r e l a t i o n between T p p and Pp f o r g a s o l i n e a t A = 0.9 93 F i g . 4 7 c o r r e l a t i o n between T and p f o r PP P methane a t \ = 1 . 3 94 v i i i F i g . 4 8 c o r r e l a t i o n between I and p f o r ^ 12 p g a s o l i n e a t A =0.9 94 F i g . 4 9 i o n p r o b e s i g n a l a m p l i f i e r 132 F i g . 5 0 l a t c h c i r c u i t 132 F i g . 5 1 c r a n k a n g l e d e g r e e c o u n t e r 133 F i g . 52 V, pdv/da, p ^ g e n e r a t o r 134 F i g . 5 3 imep i n t e g r a t o r 134 i x ACKNOWLEDGEMENTS I w i s h t o thank P r o f e s s o r P . G . H i l l f o r h i s s u p e r v i s i o n of th e t h e s i s and a l s o P r o f e s s o r s R . L . E v a n s , E.G.Hauptmann and E . J . D u r b i n f o r t h e g u i d a n c e g i v e n d u r i n g my g r a d u a t e s t u d i e s . I am a l s o g r a t e f u l f o r t h e a s s i s t a n c e g i v e n by t h e A l t e r n a t e F u e l s L a b o r a t o r y i n t h e a c h i e v e m e n t o f t h i s work. T h i s work was s u p p o r t e d by a g r a n t from t h e E n e r g y D e velopment Agency , t h e P r o v i n c e of B r i t i s h C o l u m b i a , Canada. X NOMENCLATURE AF ATDC bmep BTDC CR EGR imep imep imep . ie I 1 ( I 2 ' I 3 ) J 1 2 ( I 2 3 ) k MBT NOx P pP rpm A r b A r e S.I. S.T. Su T b T P P a i r - f u e l r a t i o a f t e r top dead center brake mean e f f e c t i v e pressure before top dead center compression r a t i o exhaust gas r e c i r c u l a t i o n indicated mean e f f e c t i v e pressure imep for power stroke imep for intake and exhaust stroke flame travel time in crankangle degrees between spark plug and probe 1 (2,3) flame t r a v e l time in crankangle degrees between probe 1 and 2 (2 and 3) s p e c i f i c heat r a t i o Cp/Cv minimum spark advance for best torque nitrogen oxides pressure peak pressure revolutions per minute radius change due to burning speed radius change due to expansion speed Spark-ignition Spark timing flame speed temperature of burnt gas time, in degrees crankangle after TDC, at which peak x i p r essure occurs T u temperature of the unburnt gas TDC top dead center Uj laminar flame speed u flame propagation speed u t t u r b u l e n t flame speed. V volume WOT wide open t h r o t t l e A r e l a t i v e a i r - f u e l r a t i o <J> equivalence r a t i o e expansion r a t i o p gas d e n s i t y 1 I . INTRODUCTION S i n c e 1980, t h e A l t e r n a t e F u e l s • L a b o r a t o r y (AFL) a t t h e M e c h a n i c a l E n g i n e e r i n g D epartment has i n v e s t i g a t e d s e v e r a l a s p e c t s of n a t u r a l gas c o n v e r s i o n . The t h r e e main a r e a s of i n t e r e s t a r e - s t o r a g e c a p a c i t y and range - f u e l l i n g and gas c a r b u r e t o r s - c o m b u s t i o n p r o c e s s e s The q u e s t i o n o f s t o r a g e c a p a c i t y i s a p p a r e n t l y t h e main p r o b l e m a f f e c t i n g t h e w i d e s p r e a d use of n a t u r a l gas as a a u t o m o b i l e use s i n c e , under c u r r e n t t e c h n o l o g y , n a t u r a l gas must be s t o r e d i n l a r g e , h e a v y - w e i g h t t a n k s a t h i g h p r e s s u r e . G a s o l i n e c a r b u r e t o r s have been d e v e l o p e d t o a h i g h .degree of s o p h i s t i c a t i o n but l i t t l e r e s e a r c h has been done on gas c a r b u r e t o r s , w h i c h must be a b l e t o m a i n t a i n an o p t i m a l a i r - f u e l r a t i o under s t a t i c and dynamic c o n d i t i o n s f o r t h e whole o p e r a t i n g r a n g e of t h e c a r . F i n a l l y , t h e c o m b u s t i o n p r o c e s s has few p r o b l e m s . The low f u e l c o s t and low p o l l u t i o n l e v e l a r e t h e main r e a s o n s t o promote a c o n v e r s i o n p r o g r a m . B e s i d e s t h e i n h e r e n t power l o s s b e c a u s e p a r t o f t h e a i r i s r e p l a c e d by g a s e o u s f u e l , t h e l o s s a t h i g h e n g i n e s p e e d i s more s u b s t a n t i a l s i n c e methane b u r n s s l o w e r t h a n g a s o l i n e . Methane f l a m e s p e e d has been t h e s u b j e c t of numerous i n v e s t i g a t i o n s i n t h e p a s t but v e r y few d e a l w i t h 2 i t s c o m b u s t i o n i n e n g i n e s . The c o m b u s t i o n p r o c e s s d e p e n d s on s e v e r a l f a c t o r s : i g n i t i o n , t u r b u l e n c e , f l a m m a b i l i t y , p r e s s u r e and t e m p e r a t u r e c o n d i t i o n s , r e a c t i o n k i n e t i c s and so on. Most o f t h e s e e f f e c t s have been s t u d i e d i n s t a t i c d e v i c e s s u c h as c o n s t a n t volume c o m b u s t i o n bombs, fl a m e t u b e s and b u r n e r s . T h e s e s t u d i e s were c o n d u c t e d p r i m a r i l y b e c a u s e of t h e w i d e s p r e a d use of n a t u r a l g a s i n i n d u s t r y . However, t h e y a r e u s e f u l i n u n d e r s t a n d i n g t h e p r o c e s s e s w h i c h t a k e p l a c e i n a s p a r k - i g n i t i o n e n g i n e . The g o a l of t h i s s t u d y i s t o i n v e s t i g a t e t h e c o m b u s t i o n d i f f e r e n c e s between n a t u r a l gas and g a s o l i n e i n a s p a r k -i g n i t i o n e n g i n e . T h i s i n v e s t i g a t i o n was p e r f o r m e d by m e a s u r i n g f l a m e s p e e d and p r e s s u r e d e v e l o p m e n t , as w e l l as power o u t p u t , power v a r i a t i o n f r o m c y c l e t o c y c l e and . t h r o u g h t h e c o r r e l a t i o n s between t h o s e measurements. In a d d i t i o n , e n g i n e p e r f o r m a n c e was s i m u l a t e d on a computer t o c o n t r i b u t e t o t h e u n d e r s t a n d i n g of t h e s e p r o c e s s e s . 1.1 M a t h e m a t i c a l S i m u l a t i o n of E n g i n e P e r f o r m a n c e E n g i n e p e r f o r m a n c e d a t a f o r d i f f e r e n t f u e l s , k e e p i n g a l l o t h e r p a r a m e t e r s c o n s t a n t ( i g n i t i o n , e n g i n e d e s i g n , s p e e d ) , d i f f e r b e c a u s e of c h a n g e s i n g a s c o m p o s i t i o n , g a s e o u s r a t h e r t h a n l i q u i d f u e l s u p p l y , h e a t i n g v a l u e of t h e f u e l , and t h e r e a c t i o n r a t e s w h i c h d e t e r m i n e t h e f l a m e s p e e d . The i n f l u e n c e o f h e a t i n g v a l u e i s c l e a r l y u n d e r s t o o d and t h e e f f e c t on c y l i n d e r f u e l d i s t r i b u t i o n of t h e l i q u i d or g a s e o u s s t a t e of 3 the f u e l i s d i f f i c u l t to model. T h e r e f o r e , only the performance change due to gas composition ( s p e c i f i c heat, d i s s o c i a t i o n ) and flame speed was simulated using computer models. Two programs were prepared in order . to separate the i n f l u e n c e s . They c o n t r i b u t e d to an understanding of the engine behaviour and the, experimental r e s u l t s . 1.2 Engine Experiments The A l t e r n a t e F u e l s Laboratory i n i t i a l l y set up a s i n g l e c y l i n d e r a i r c o o l e d engine. The main c o n s t i t u e n t of n a t u r a l gas i s methane, which was used i n the experiments. To study the combustion processes, a separate engine head was equipped with a pressure transducer and flame d e t e c t o r s . From these s i g n a l s , both f u e l s c o u l d be compared for power output, flame speed, c y c l e - t o - c y c l e v a r i a t i o n and p r e s s u r e development. For t h i s p r o j e c t , i t was necessary to b u i l d a data a c q u i s i t i o n system as i t was not a v a i l a b l e at that time i n the Mechanical E n g i n e e r i n g Department. A s p e c i a l f e a t u r e of the system was the p o s s i b i l i t y of s tudying c y c l e - t o - c y c l e v a r i a t i o n s over a l a r g e number of c y c l e s , t y p i c a l l y 500. T h i s was necessary as some measured v a r i a b l e s l i k e flame propagation show a very l a r g e v a r i a n c e . A computer program was used to o b t a i n a s t a t i s t i c a l a n a l y s i s of the s i g n a l s f o r each t e s t c o n d i t i o n of the engine. 4 T h i s s t u d y showed t h a t t h e f l a m e p r o p a g a t i o n speed f o r b o t h f u e l s i s t h e same a t t h e t o p dead c e n t e r of t h e p i s t o n where t h e c o m p r e s s i o n i s h i g h e s t . O p e r a t i n g c o n d i t i o n s were i d e n t i c a l i n b o t h c a s e s e x c e p t t h a t methane was i g n i t e d e a r l i e r i n o r d e r t o o b t a i n maximum work. The r e a s o n f o r t h i s was t h e l o n g e r i g n i t i o n d e l a y , as measured by the f l a m e d e t e c t o r c l o s e t o t h e s p a r k p l u g . I t was a l s o n o t e d from t h e measurements t h a t a t e l e v a t e d t e m p e r a t u r e and p r e s s u r e , t h e methane f l a m e s p e e d i s l o w e r t h a n t h a t of g a s o l i n e so t h a t t h e c o m b u s t i o n p e r i o d e x t e n d s more i n t o t h e e x p a n s i o n s t r o k e of t h e e n g i n e . T h i s e f f e c t i s e m p h a s i z e d a t h i g h e r e n g i n e speeds r e s u l t i n g i n a more s u b s t a n t i a l power l o s s , r e l a t i v e t o t h e l o w e r s p e e d r e g i o n . 5 I I . ENGINE PARAMETERS 11 . 1 I n t r o d u c t i o n In t h i s c h a p t e r , a q u a l i t a t i v e d i s c u s s i o n of e n g i n e p e r f o r m a n c e i s g i v e n by d e s c r i p t i o n of t h e e n g i n e v a r i a b l e s . I t i s p o s s i b l e t o make a c l a s s i f i c a t i o n i n t o t h e e n g i n e c o n t r o l p a r a m e t e r s ( i n d e p e n d e n t v a r i a b l e s ) and t h e d e p e n d e n t or o u t p u t v a r i a b l e s . The r e l a t i o n s h i p s between t h e v a r i a b l e s a r e d i s c u s s e d and t h e t e r m s , o f t e n q u o t e d i n t h i s f i e l d , w i l l be e x p l a i n e d t h r o u g h o u t t h e t e x t . E x h a u s t e m i s s i o n s a r e not d i s c u s s e d s i n c e no i n v e s t i g a t i o n s were done i n t h i s a r e a . I I . 2 I n d e p e n d e n t V a r i a b l e s  a) t h r o t t l e p o s i t i o n C o n t r a r y t o t h e c o m p r e s s i o n i g n i t i o n e n g i n e , which can o p e r a t e o v e r a wide r a n g e of f u e l - a i r m i x t u r e s t r e n g t h s and a t h i g h c o m p r e s s i o n r a t i o , a s p a r k - i g n i t i o n e n g i n e has a l i m i t e d r ange o f f u e l - a i r r a t i o and i s l i m i t e d t o a l o w e r c o m p r e s s i o n r a t i o . I f t h e c o m p r e s s i o n r a t i o i s t o o h i g h , a g a s o l i n e - a i r m i x t u r e would i g n i t e on i t s own g i v i n g u n c o n t r o l l e d c o m b u s t i o n ( k n o c k ) . The c o m b u s t i o n a t t h e low c o m p r e s s i o n r a t i o r e l i e s on f l a m e p r o p a g a t i o n s t a r t i n g from an i g n i t i o n p o i n t . The f u e l - a i r r a t i o i s l i m i t e d by i g n i t i o n p r o b l e m s o r f l a m e e x t i n c t i o n . Power t h e r e f o r e has t o be c o n t r o l l e d by v a r i a t i o n of t h e m i x t u r e mass f l o w . A t c o n s t a n t e n g i n e s p e e d , t h e a i r flow. 6 depends p r i m a r i l y on t h r o t t l e p o s i t i o n and i s maximum a t wide open t h r o t t l e (WOT). b) a i r - f u e l r a t i o A m i x t u r e has a s t o i c h i o m e t r i c a i r - f u e l r a t i o when t h e amount of oxygen a v a i l a b l e g i v e s c o m p l e t e c o m b u s t i o n of t h e f u e l , w i t h o u t d i s s o c i a t i o n and w i t h o u t e x c e s s oxygen i n t h e c o m b u s t i o n p r o d u c t s . The r e l a t i v e a i r - f u e l r a t i o \ i s t h e r a t i o of t h e r e a l t o t h e s t o c h i o m e t r i c a i r - f u e l r a t i o . The i n v e r s e i s c a l l e d e q u i v a l e n c e r a t i o . The m i x t u r e c o m p o s i t i o n coming from t h e c a r b u r e t o r can be c h a n g e d by e x h a u s t gas r e c i r c u l a t i o n (EGR). c) i g n i t i o n t i m i n g In t h e a i r - s t a n d a r d O t t o c y c l e , i t i s assumed t h a t c o m b u s t i o n t a k e s p l a c e a t t o p d e a d c e n t e r ( T D C ) . The e f f i c i e n c y i s t h e n maximum. The c o m b u s t i o n i s not i n s t a n t a n e o u s i n r e a l e n g i n e s and i n o r d e r t o a p p r o x i m a t e t h e t h e o r e t i c a l c y c l e , i g n i t i o n i s a d v a n c e d b e f o r e TDC. O v e r a d v a n c i n g t h e s p a r k t i m i n g would c a u s e p r e s s u r e t o r i s e t o o e a r l y . T h e r e i s an o p t i m a l p o i n t w h i c h i s c a l l e d t h e minimum advance f o r b e s t t o r q u e (MBT) t i m i n g . d) e n g i n e speed The l o a d w h i c h i s a p p l i e d t o t h e e n g i n e c an be v a r i e d t o 7 o b t a i n a c e r t a i n e n g i n e s p e e d . Speed v a r i a t i o n s of 5% can o c c u r d u r i n g one e n g i n e c y c l e . I I . 3 Dependent V a r i a b l e s a) work and power The work d e v e l o p e d by t h e c y l i n d e r g a s e s d u r i n g one e n g i n e c y c l e i s t h e i n t e g r a l of pdV. The work depends on t h e e n g i n e s i z e so t h a t t h e work p e r u n i t p i s t o n d i s p l a c e m e n t i s b e t t e r f o r c o m p a r i n g t h e p e r f o r m a n c e of e n g i n e s of d i f f e r e n t s i z e s and d e s i g n s . T h i s t e r m i s . c a l l e d t h e i n d i c a t e d mean e f f e c t i v e p r e s s u r e ( i m e p ) , h a v i n g t h e same u n i t s as p r e s s u r e . The term bmep r e f e r s t o t h e b r a k e work and i s t h e work done on t h e b r a k e i n one t o t a l e n g i n e c y c l e , d i v i d e d by t h e p i s t o n d i s p l a c e m e n t . From t h e t h e o r y of t h e s t a n d a r d O t t o a i r c y c l e , i t i s known t h a t e n g i n e work i s maximum f o r i n s t a n t a n e o u s c o m b u s t i o n a t t o p dead c e n t e r and i f t h e r e a r e no h e a t l o s s e s t o t h e e n g i n e w a l l s . F i g . 1 from Born [ 1 ] , shows a p-V d i a g r a m of an a c t u a l e n g i n e c y c l e and t h e d e v i a t i o n s from t h e t h e o r e t i c a l c y c l e a r e i n d i c a t e d . b) f u e l economy F u e l economy depends s t r o n g l y on a i r - f u e l r a t i o and i g n i t i o n t i m i n g . T y p i c a l p e r f o r m a n c e i s shown i n F i g . 2 , Z e i l i n g e r [ 2 ] , I t i s seen t h a t f u e l economy i s p a r t i c u l a r l y s e n s i t i v e t o i g n i t i o n t i m i n g a t l e a n a i r - f u e l r a t i o s . 8 c) c o m b u s t i o n F i g . 3 by Benson e t a l [3] shows how t h e p r e s s u r e c h a n g e s d u r i n g t h e c o m b u s t i o n . The f l a m e s t a r t s from t h e i g n i t i o n p o i n t ( p o i n t A on F i g . 3 ) and i t needs a c e r t a i n t i m e t o d e v e l o p i n t o a f u l l y s e l f - s u s t a i n i n g p r o p a g a t i n g f l a m e ( p o i n t B ) . The f l a m e f r o n t t h e n t r a v e l s t h r o u g h t h e chamber u n t i l t h e t o t a l m i x t u r e i s b u r n t ( p o i n t C on F i g . 3 ) . D u r i n g t h e i n i t i a l s t a g e , t h e p r e s s u r e does not d i f f e r f r o m t h e c o m p r e s s i o n p r e s s u r e . A n o t h e r c l a s s i f i c a t i o n i s sometimes made when t a k i n g t h e p r o p o r t i o n o f t h e m i x t u r e mass wh i c h i s b u r n t . The u s u a l e m p i r i c a l d e f i n i t i o n s a r e made on t h e b a s i s of t h e mass f r a c t i o n b u r n t : 0-10% b u r n t p e r i o d i s d e f i n e d as i g n i t i o n d e l a y and t h e 10-90% b u r n t p e r i o d as c o m b u s t i o n d u r a t i o n . The amount of b u r n t f u e l mass c a n n o t be measured d i r e c t l y but has t o be c a l c u l a t e d from c y l i n d e r p r e s s u r e measurements. The i n t e r a c t i o n between p r e s s u r e d e v e l o p m e n t and i g n i t i o n t i m i n g i s shown i n F i g . 4 , Benson e t a l [ 3 ] . The p o i n t of maximum power o r imep i n t h i s f i g u r e c o r r e s p o n d s t o t h e MBT t i m i n g . An i m p o r t a n t f a c t o r i n t h e c o m b u s t i o n p r o c e s s i s t h e c y c l e - t o - c y c l e v a r i a t i o n i n t h e p r e s s u r e d e v e l o p m e n t . The main c a u s e , b e s i d e s f u e l d i s t r i b u t i o n , i s t h e m i x t u r e m o t i o n i n t h e c y l i n d e r . R e c e n t r e s e a r c h has f o c u s e d on e n g i n e g e o m e t r i e s w h i c h promote a f a s t f l a m e s i n c e t h i s w ould improve t h e e n g i n e s t a b i l i t y a t l e a n e r m i x t u r e s , where e f f i c i e n c y i s h i g h e s t . 9 b,lg/PSh] lPSh=0.735 kWh 0 S . l I . «20°BTDC / c \ ft\\ % 2500 r pra / / /" V / V > 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 - A 3000 rev/min Equivalence ratio 0 = 1-0 Fig.1: p-V diagram and engine losses [1] Fig.2: f u e l consumption as a function of spark timing and a i r / f u e l r a t i o [2] Fig.3; combustion stages i n a spark-ignition engine [3] (theoretical case) -120 -80 BTOC 0 40 B0 120 TDC (crankangle deg) AT DC 10 F i g . 4 : e n g i n e w o r k ( i m e p ) , p e a k p r e s s u r e a n d i t s a r r i v a l t i m e a s f u n c t i o n s o f i g n i t i o n a d v a n c e [3] 11 I I I . LITERATURE REVIEW T h i s r e v i e w c o v e r s a s e l e c t i o n of p a p e r s w h i c h d e s c r i b e c o m b u s t i o n phenomena i n s p a r k - i g n i t i o n e n g i n e s g e n e r a l l y b e f o r e f o c u s s i n g on what i s known ab o u t t h e c o m b u s t i o n o f n a t u r a l g a s . I I I . l C o m b u s t i o n i n S p a r k - i g n i t i o n E n g i n e s The t o p i c s of p r i n c i p a l i n t e r e s t a r e i g n i t i o n d e l a y , b u r n i n g r a t e , c y c l e - t o - c y c l e v a r i a t i o n , f l a m m a b i l i t y , c y l i n d e r p r e s s u r e d e v e l o p m e n t , the g a s e o u s or l i q u i d s t a t e of t h e f u e l and p e r f o r m a n c e c a l c u l a t i o n s . T h e s e t o p i c s a r e d e s c r i b e d i n t h e n e x t s e c t i o n s . a) c y c l e - t o - c y c l e v a r i a t i o n F o r t h e p a s t 25-30 y e a r s , c y c l e - t o - c y c l e v a r i a t i o n s have been s t u d i e d and i t was f o u n d t h a t c o m b u s t i o n v a r i a t i o n s a r e t h e main c a u s e . G e n e r a l l y , i t i s a c c e p t e d t h a t f a s t burn c y c l e s show s m a l l e r v a r i a n c e i n p r e s s u r e d e v e l o p m e n t and hence i n power o u t p u t . The r e a s o n i s t h a t t h e c y l i n d e r volume a t TDC i s a l m o s t c o n s t a n t and p r e s s u r e v a r i a t i o n s have l i t t l e e f f e c t on 1 2 t h e work pdV. Slow burn c y c l e s w i t h p r e s s u r e v a r i a t i o n s w e l l b e f o r e and a f t e r TDC g i v e t h e r e f o r e l a r g e r v a r i a t i o n s i n work. The i g n i t i o n d e l a y p e r i o d , j u s t a f t e r i g n i t i o n , i s of main i m p o r t a n c e t o t h e s e c o m b u s t i o n e f f e c t s [ 4 ] . The i g n i t i o n d e l a y p e r i o d i s p r e c e d e d by a f a i r l y s t a b l e f l a m e k e r n e l g r o w t h and C u r r y [ 5 ] shows, w i t h t h e use of i o n i z a t i o n p r o b e s , t h a t t h i s i n i t i a l k e r n e l has l i t t l e v a r i a n c e i n p r o p a g a t i o n s p e e d . T h e r e i s however a d i s c u s s i o n as t o what f a c t o r s and t o what e x t e n t t h e y i n f l u e n c e t h i s i g n i t i o n d e l a y . I t i s f o u n d [6] t h a t t h e e n g i n e shows t h e s m a l l e s t o u t p u t v a r i a t i o n s a t t h e e q u i v a l e n c e r a t i o w hich g i v e s maximum power. F o r most f u e l s , t h i s means t h a t t h e m i x t u r e c o m p o s i t i o n i s s l i g h t l y r i c h e r t h a n t h e s t o c h i o m e t r i c f u e l - t o - a i r r a t i o [ 6 ] . . T h i s i s c o n s i s t e n t w i t h t h e e a r l i e r s t a t e m e n t s i n c e f l a m e t r a v e l i s f a s t e s t a t t h i s e q u i v a l e n c e r a t i o . B e c a u s e o f t h e l o w e r h e a t i n g v a l u e per u n i t mass of m i x t u r e , c h a r g e d i l u t i o n w i l l l o w e r t h e c o m b u s t i o n t e m p e r a t u r e and slow down t h e f l a m e w h i c h e x t e n d s t h e b u r n i n g p e r i o d . T h i s r e s u l t s t h e n i n h i g h e r c o m b u s t i o n v a r i a n c e as d e s c r i b e d by Mayo [ 7 ] , T u t t l e e t a l . [8] and Kuroda e t a l [ 9 ] . I t i s l e s s c l e a r whether c y c l e - t o - c y c l e v a r i a t i o n s i n d i l u t i o n ( m a i n l y E x h a u s t Gas R e c i r c u l a t i o n EGR) a r e t h e r e a s o n or whether o t h e r c a u s e s l i k e t u r b u l e n c e have a l a r g e r e f f e c t when t h e c y l i n d e r m i x t u r e i s d i l u t e d . T h i s i s d i s c u s s e d by M a tsuoka e t a l [10] and W i n s o r e t a l [11']. The i g n i t i o n p r o c e s s as i t t a k e s p l a c e i n t h e e n g i n e i s v e r y r e p e a t a b l e and has t h e r e f o r e l i t t l e e f f e c t on c o m b u s t i o n v a r i a n c e . However, c o m b u s t i o n d u r a t i o n depends of c o u r s e on the. 1 3 number of i g n i t i o n p o i n t s , t h e i r l o c a t i o n and t i m i n g so t h a t t h e y can be o p t i m i z e d f o r minimum power v a r i a t i o n [ 6 ] , [ 9 ] . Compact c o m b u s t i o n chamber g e o m e t r i e s w i t h a s h o r t f l a m e t r a v e l f a v o u r f a s t b u r n r a t e s and hence low v a r i a n c e [ 1 2 ] . I m p o r t a n t f o r t h i s work i s t h e e f f e c t of a l i q u i d f u e l v e r s u s g a s e o u s f u e l . Some s t u d i e s [10] i n d i c a t e t h a t i t i s p o s s i b l e t o have v a r i a t i o n s i n m i x t u r e s t r e n g t h even w i t h g a s e o u s f u e l . I t i s a l s o p o s s i b l e t o have f a s t e r c o m b u s t i o n w i t h l e s s p r e m i x e d f l a m e s , see P e t e r s e t a l [ 1 3 ] , but a p o s s i b l e e x p l a n a t i o n f o r t h i s i s s t r a t i f i c a t i o n . Yu [14] has s t u d i e d t h e p r o b l e m but f a i l e d t o make t h e d i s t i n c t i o n between o v e r - a l l c h a n g e s i n a i r - f u e l r a t i o f r o m c y c l e t o c y c l e and t h e f u e l d i s t r i b u t i o n c h a n g e s w i t h i n t h e c y l i n d e r , s i n c e he took a sample of t h e c y l i n d e r m i x t u r e a t a f i x e d p o i n t i n t h e c y l i n d e r . I t i s g e n e r a l l y a c c e p t e d t h a t r n - c y l i n d e r gas m o t i o n s a r e t h e main c a u s e f o r c o m b u s t i o n v a r i a t i o n s . T h i s i s d e s c r i b e d by s e v e r a l i n v e s t i g a t o r s : O v e r i n g t o n e t a l [ 1 5 ] , P a t t e r s o n [ 6 ] , W i n s o r e t a l [ 1 1 ] , M a t t a v i [ 1 6 ] , L u c a s e t a l [ 1 7 ] , Mayo [ 7 ] , T u t t l e e t a l [ 8 ] , T h r i n g [18] and Matsuoka e t a l [ 1 0 ] . A major e f f o r t has been made ( b o t h i n R a p i d C o m p r e s s i o n M a c h i n e s , c o m b u s t i o n bombs and e n g i n e s ) t o measure t h e i n f l u e n c e o f d i f f e r e n t t y p e s of m i x t u r e m o t i o n : t u r b u l e n c e , s w i r l and s q u i s h . S e v e r a l f u n d a m e n t a l s t u d i e s have i n v e s t i g a t e d t h e i r e f f e c t on t h e f l a m e s p e e d d u r i n g t h e d i f f e r e n t s t a g e s i n c o m b u s t i o n . 1 4 b) c y c l e c a l c u l a t i o n s T h e r e e x i s t s e v e r a l a p p r o a c h e s t o c a l c u l a t e t h e p e r f o r m a n c e f o r e n g i n e s . The s i m p l e s t way i s t h e a i r - s t a n d a r d O t t o c y c l e [ 1 9 ] [ 2 0 ] , w h i c h assumes a c o m b i n a t i o n of a d i a b a t i c volume c h a n g e s and h e a t t r a n s f e r a t c o n s t a n t volume t o s i m u l a t e c o m b u s t i o n . C y l i n d e r gas i s i d e a l w i t h c o n s t a n t s p e c i f i c h e a t . C o m p l i c a t e d s i m u l a t i o n m o d e l s , as made by Benson e t a l [21] and Blumberg e t a l [22] i n c l u d e : h e a t t r a n s f e r m o d e l s , gas d i s s o c i a t i o n , NOx r e a c t i o n k i n e t i c s , l i m i t e d f l a m e s p eed and s i m u l a t i o n of t h e i n t a k e p r o c e s s . An i n t e r e s t i n g a p p r o a c h i s t o i n v e s t i g a t e t h e a s s u m p t i o n s made s e p a r a t e l y i n d i f f e r e n t p r o g r a m s . Gas d i s s o c i a t i o n l o w e r s t h e c o m b u s t i o n t e m p e r a t u r e and e q u i l i b r i u m c h a r t s a r e made [ 2 0 ] [ 2 3 ] t o i n c l u d e t h i s e f f e c t , t o g e t h e r w i t h r e a l gas p r o p e r t i e s , i n t h e a i r - s t a n d a r d O t t o c y c l e . Benson e t a l [3] u s e d a n a l y t i c a l e x p r e s s i o n s and a computer program- f o r t h i s p u r p o s e . The f i n i t e b u r n i n g r a t e i s i m p o r t a n t f o r t h i s s t u d y and a program was made i n c l u d i n g t h i s a s an a d d i t i o n a l f e a t u r e t o t h e a i r - s t a n d a r d O t t o c y c l e ( s e e l a t e r i n c h a p t e r I V . 3 ) . I I I . 2 Methane R e s e a r c h S i n c e methane i s t h e main c o n s t i t u e n t o f n a t u r a l g as, i t has been- t h e s u b j e c t o f numerous s t u d i e s w h i c h a t t e m p t t o 1 5 d e t e r m i n e i t s b u r n i n g c h a r a c t e r i s t i c s . S e v e r a l r e s u l t s a r e g i v e n i n t h i s s e c t i o n on f l a m e s p e e d . R e s e a r c h on n a t u r a l gas use i n s p a r k - i g n i t i o n e n g i n e s has been m a i n l y d i r e c t e d t o w a r d s i t s l o w e r e x h a u s t e m i s s i o n s . a) methane c o m b u s t i o n i n e n g i n e s Of p r i m a r y i m p o r t a n c e i s whether n a t u r a l gas i s s u i t a b l e f o r e n g i n e o p e r a t i o n . I t i s a c l e a n n o n - t o x i c f u e l and i t s h i g h knock r a t i n g has been known f o r a l o n g t i m e . K a r i m e t a l [25] have d e t e r m i n e d i t s knock and i g n i t i o n l i m i t s under v a r y i n g c o n d i t i o n s s u c h as f u e l - a i r r a t i o , c o m p r e s s i o n r a t i o and i n t a k e t e m p e r a t u r e . They a l s o i n v e s t i g a t e d t h e e x h a u s t e m i s s i o n and o p e r a t i o n c h a r a c t e r i s t i c s . The same a p p r o a c h has been t a k e n by Lee e t a l [ 2 6 ] , P e a r c e [ 2 7 ] , Moore e t a l [28] and C h r i s t o p h e t a l [ 2 9 ] . An i n v e s t i g a t i o n i n t o t h e k i n e t i c s o f t h e r e a c t i o n s i n v o l v i n g methane has been done by K a r i m e t a l [ 3 0 ] . The aim of t h i s t h e s i s i s t o g i v e f u r t h e r i n s i g h t i n t o p h y s i c a l v a r i a b l e s s u c h as IMEP and b u r n i n g s p e e d compared t o g a s o l i n e . b) f l a m e s p e e d The pr i n c i p a l p a r a m e t e r s f o r t h e d e t e r m i n a t i o n of m e t h a n e - a i r 16 f l a m e s p e e d a r e e q u i v a l e n c e r a t i o , f lame f r o n t t h i c k n e s s , p r e s s u r e and u n b u r n t gas t e m p e r a t u r e . These a r e d i s c u s s e d by Ryan e t a l [ 3 1 ] , Andrews e t a l [ 3 2 ] , T s a t s a r o n i s [33] and G a r f o r t h e t a l [34] . Of p a r t i c u l a r i n t e r e s t a r e t e s t s p e r f o r m e d under e n g i n e -l i k e c o n d i t i o n s s u c h as t h o s e done by H a l s t e a d e t a l [35] w i t h a R a p i d C o m p r e s s i o n M a c h i n e . T h e i r r e s u l t s f o r f l a m e s p e e d compared f a i r l y w e l l w i t h t h o s e o f Andrews e t a l [32] o b t a i n e d i n a c o n s t a n t volume bomb e x p e r i m e n t . H a l s t e a d e t a l [35] a l s o r e p o r t e d a f l a m m a b i l i t y l i m i t of 39 A/F r a t i o (T=710K, P=l9.4atm) as o p p o s e d t o 33 A/F r a t i o f o r g a s o l i n e a t t h e same c o n d i t i o n s . Andrews and B r a d l e y [32] compared p r e v i o u s , s t u d i e s w i t h t h e i r work and r e p o r t e d t h e f o l l o w i n g e q u a t i o n s f o r . t h e f l a m e s p e e d of a m e t h a n e - a i r m i x t u r e : P = p r e s s u r e atm T=unburnt gas t e m p e r a t u r e d e g r e e s K 0 = e q u i v a l e n c e r a t i o Su=flame s p e e d cm/sec Range c o n d i t i o n f l a m e s p e e d 300K<T<1000K P=1atm P>4atm T=298K O.7<0<1.5 T=298K P=1atm Su=10+0.000371Tu 2cm/sec Su=43P _ °« 5cm/sec Su = 43-300(jZM .06) 2 c m / s e c q u a d r a t i c a p p r o x i m a t i o n f o r g r a p h i n r e f [ 3 2 ] 18 IV. ENGINE PERFORMANCE CALCULATION In t h i s c h a p t e r , c h a n g e s i n p e r f o r m a n c e due t o t h e use of d i f f e r e n t f u e l s a r e c a l c u l a t e d . As m e n t i o n e d i n t h e i n t r o d u c t i o n , t h e g a s e o u s s t a t e of methane may g i v e b e t t e r f u e l d i s t r i b u t i o n t h an l i q u i d g a s o l i n e . S i n c e t h i s e f f e c t i s d i f f i c u l t t o p r e d i c t , o n l y t h e c o m b u s t i o n p r o b l e m , a s s u m i n g a homogeneous m i x t u r e , was examined. IV.1 C a l o r i f i c V a l u e of t h e F u e l A s i m p l e a n a l y s i s w i l l g i v e an i n d i c a t i o n of t h e power l o s s of the. e n g i n e when f u e l l e d w i t h methane i n s t e a d of g a s o l i n e ( s e e A p p e n d i x A ) . The r e s u l t o b t a i n e d f o r t h e c a l o r i f i c v a l u e of g a s o l i n e e n c l o s e d i n t h e c y l i n d e r i s 3.5 MJ/m 3 c y l i n d e r volume a t s t o i c h i o m e t r i c c o n d i t i o n s . F o r t h i s c a l c u l a t i o n , t h e g a s o l i n e f u e l was t a k e n i n i t s l i q u i d f o r m . A l t h o u g h methane has a h i g h e r c a l o r i f i c v a l u e (50 MJ/kg m e t h a n e ) , a s t o c h i o m e t r i c f u e l - a i r m i x t u r e has o n l y a c a l o r i f i c c o n t e n t o f 3.2 MJ/m 3 c y l i n d e r volume, m a i n l y b e c a u s e of a i r r e p l a c e m e n t by methane. T h e r e f o r e , t h e h e a t r e l e a s e d d u r i n g c o m b u s t i o n , and hence t h e power, i s 9% l e s s w i t h methane t h a n w i t h g a s o l i n e . S l i g h t v a r i a t i o n s i n t h e power l o s s may o c c u r due t o a d i f f e r e n t c o m p o s i t i o n of g a s o l i n e and i t s s t o c h i o m e t r i c a i r - t o -f u e l r a t i o . 19 S i m i l a r c a l c u l a t i o n s show t h a t methane d e v e l o p s 6% l e s s power t h a n i s o o c t a n e i n g a s e o u s s t a t e . In a d d i t i o n t o t h e i n f l u e n c e of c a l o r i f i c v a l u e , o t h e r f a c t o r s a f f e c t i n g t h e power o u t p u t when c o m p a r i n g b o t h f u e l s i n c l u d e a) h e a t t r a n s f e r b) gas c o m p o s i t i o n c) f l a m e s p e e d T h e r e i s i n s u f f i c i e n t e x p e r i m e n t a l d a t a a v a i l a b l e i n o r d e r t o g i v e i n f o r m a t i o n on t h e h e a t t r a n s f e r e f f e c t . F o r t h e two. r e m a i n i n g f a c t o r s , s i m u l a t i o n p r ograms were s e t up t o c a l c u l a t e t h e i r e f f e c t on t h e e n g i n e c y c l e . 20 IV.2 Gas C o m p o s i t i o n F o r a s t o c h i o m e t r i c m i x t u r e , t h e c h e m i c a l r e a c t i o n s w i t h o u t d i s s o c i a t i o n f o r b o t h f u e l s a r e : a) methane CH, + 2 ( 0 „ + 3.76N ) -y C O „ + 2H 0 + 2x3.76N 4 2 2 2 2 2 b) g a s o l i n e ( i s o o c t a n e ) CLH + 1 2 . 5 ( 0 0 + 3.76N ) + 8 C 0 o + 9H O +. 1 2. 5x3 . 76ti o l o 2. 2 . 2 2 2 A g a s o l i n e - a i r m i x t u r e c a n be c o n s i d e r e d as c o n t a i n i n g o n l y a i r f o r c a l c u l a t i n g i t s gas p r o p e r t i e s , w h i l e f o r a m e t h a n e - a i r m i x t u r e , t h e f u e l t a k e s a p p r o x i m a t e l y 9% of t h e volume. T h e r e f o r e , a d i f f e r e n c e i n c o m p r e s s i o n p r e s s u r e c a n be e x p e c t e d b e c a u s e o f a d i f f e r e n c e i n s p e c i f i c h e a t . The c o m b u s t i o n g a s e s f o r a methane f u e l l e d e n g i n e c o n t a i n , r e l a t i v e t o t h e g a s o l i n e c a s e , more water v a p o u r and l e s s c a r b o n d i o x i d e , i f no d i s s o c i a t i o n i s c o n s i d e r e d . T h i s has an e f f e c t on t h e s p e c i f i c h e a t and t h e p r e s s u r e d u r i n g t h e e x p a n s i o n s t r o k e of t h e e n g i n e . The combined e f f e c t of t h e s p e c i f i c h e a t of t h e gas m i x t u r e , d i s s o c i a t i o n , c a l o r i f i c v a l u e and a i r d i s p l a c e m e n t by t h e g a s e o u s f u e l was s i m u l a t e d u s i n g a computer p r o g r a m 21 d e v e l o p e d by Benson e t a l [ 3 ] . T h r o u g h o u t t h e e n g i n e c y c l e c a l c u l a t i o n , t h e m i x t u r e p r o p e r t i e s were c a l c u l a t e d u s i n g a n a l y t i c a l e x p r e s s i o n s f o r t h e r e a l gas p r o p e r t i e s o f t h e m i x t u r e components. Benson e t a l assume an i d e a l m i x t u r e , w h i c h i s a c c e p t a b l e d u r i n g t h e c o m p r e s s i o n s t r o k e (low p r e s s u r e s ) and t h e e x p a n s i o n s t r o k e ( h i g h t e m p e r a t u r e s ) . T h e r e i s no h e a t t r a n s f e r t o t h e c y l i n d e r w a l l s and c o m b u s t i o n i s i n s t a n t a n e o u s a t t o p dead c e n t e r . F o r the c o m b u s t i o n and t h r o u g h o u t t h e e x p a n s i o n s t r o k e , t h e f o l l o w i n g d i s s o c i a t i o n r e a c t i o n s were c o n s i d e r e d f o r c a l u l a t i n g e q u i l i b r i u m : CO + H 2 0 t H 2 + C 0 2 CO + 0.5O 2 i c o 2 A l i s t i n g of t h i s p r o g r am i s g i v e n by Benson e t a l [3] and two sample c a l c u l a t i o n s were made f o r i s o o c t a n e and methane, b o t h a t s t o c h i o m e t r i c a i r - f u e l r a t i o and i n g a s e o u s s t a t e . The r e s u l t s a r e shown i n A p p e n d i x B. By c o m p a r i n g t h o s e two c a s e s , i t can be seen t h a t methane c o m b u s t i o n i s 2.5% more e f f i c i e n t t h a n i s o o c t a n e ( g a s e o u s s t a t e ) and d e v e l o p s 5% l e s s power t h a n i s o o c t a n e ( g a s e o u s s t a t e ) . T h i s i s ab o u t t h e same l o s s as i n t h e p r e v i o u s c a l c u l a t i o n s where o n l y c a l o r i f i c v a l u e s and a i r d i s p l a c e m e n t were compared. I t i s t h e r e f o r e c o n c l u d e d t h a t d i s s o c i a t i o n and gas c o m p o s i t i o n have l i t t l e e f f e c t on t h e d i f f e r e n c e i n power l o s s f o r t h o s e f u e l s . 22 IV.3 Flame Speed a) o b j e c t i v e A l t h o u g h t h e l a m i n a r f l a m e s p e e d f o r methane i s w e l l e s t a b l i s h e d from e x p e r i m e n t s [ 3 1 ] [ 3 2 ] [ 3 3 ] [34 ] [ 3 5 ] , few c o m p a r i s o n s have been made w i t h t h e f l a m e s p e e d of g a s o l i n e . Not o n l y i s t h e r e a d i f f e r e n c e i n b u r n i n g v e l o c i t y b u t t h e dependence on p r e s s u r e and t e m p e r a t u r e i s not t h e same f o r t h o s e f u e l s . As w e l l , t h e e f f e c t o f f l a m e f r o n t t h i c k n e s s and t u r b u l e n c e have n o t been e s t a b l i s h e d i n a c o m p a r a t i v e s t u d y . T h e r e f o r e , no a t t e m p t was made t o s i m u l a t e t h e b u r n i n g v e l o c i t y under e n g i n e - l i k e c o n d i t i o n s and t o compare t h e e n g i n e p e r f o r m a n c e of b o t h f u e l s . However, a s i m u l a t i o n p r o g ram was s e t up t o c a l c u l a t e t h e e f f e c t o f d i f f e r e n t f l a m e s p e e d s on power, e f f i c i e n c y , t i m i n g and p r e s s u r e d e v e l o p m e n t . The o b j e c t i v e was t o e s t a b l i s h t h e i m p o r t a n c e of f l a m e s p e e d , not t o p r e d i c t e n g i n e b e h a v i o u r w i t h methane v e r s u s g a s o l i n e . b) method The program r e l i e d on t h e a i r - s t a n d a r d O t t o c y c l e [19] but i n s t e a d of a d d i n g h e a t a t t o p dead c e n t e r t o s i m u l a t e c o m b u s t i o n , a s m a l l k e r n e l of m i x t u r e ( r a d i u s 2mm) was b u r n e d a t a c e r t a i n i g n i t i o n a d v a n c e b e f o r e t o p dead c e n t e r . A s p h e r i c a l f l a m e f r o n t p r o p a g a t e d from t h i s k e r n e l d i v i d i n g t h e c y l i n d e r i n t o a b u r n t and u n b u r n t z o n e . T h i s p r o p a g a t i o n s p e e d 23 was a c o m b i n a t i o n of an e m p i r i c a l f l a m e s p e e d ( f l a m e t r a v e l r e l a t i v e t o t h e u n b u r n t zone) and an e x p a n s i o n s p e e d , due t o t h e e x p a n s i o n of t h e c o m b u s t i o n g a s e s i n o r d e r t o keep a u n i f o r m p r e s s u r e t h r o u g h o u t t h e c y l i n d e r . C o m b u s t i o n was s i m u l a t e d by h e a t t r a n s f e r t o t h e c y l i n d e r a i r m i x t u r e , g i v i n g an e n e r g y i n c r e a s e e q u a l t o t h e c a l o r i f i c v a l u e o f t h e b u r n i n g f r a c t i o n . The c a l c u l a t i o n scheme i s e x p l a i n e d i n F i g . 5 f l a m e f r o n t F i g . 5 : b u r n i n g and e x p a n s i o n s p e e d of a p r o p a g a t i n g f l a m e F o r t h e f l a m e s p e e d , an e m p i r i c a l e q u a t i o n f o r p r o p a n e , d e v e l o p e d by K u e h l [36],was u s e d . I t was m u l t i p l i e d by a f a c t o r K t o a c c o u n t f o r t u r b u l e n c e so t h a t c o m b u s t i o n d u r a t i o n was c o m p a r a b l e w i t h e x p e r i m e n t a l d a t a f o u n d i n l i t e r a t u r e . T h e r e was no need f o r an a c c u r a t e model o f methane f l a m e s p e e d s i n c e t h e o b j e c t i v e was t o s t u d y q u a l i t a t i v e l y t h e i n f l u e n c e o f l i m i t e d f l a m e s p e e d on e n g i n e p e r f o r m a n c e . 24 K u e h l ' s e x p r e s s i o n f o r t h e l a m i n a r f l a m e s p e e d i s = 1 . 0 8 7 X 1 0 6 X ( l O « / T b + 9 0 0 / T u ) - « • 9 3 8 x p * 0 ' 0 5 8 7 cm/sec T b b u r n t gas t e m p e r a t u r e T u u n b u r n t gas t e m p e r a t u r e p p r e s s u r e i n i n c h e s m e r c u r y The t u r b u l e n t model i s t h e n u f c = Kxu.^ . In a t i m e s t e p At, t h e amount of m i x t u r e t o be b u r n t i s g i v e n by t h e r a d i u s change Ar, = u, x A t b t In o r d e r t o o b t a i n u n i f o r m p r e s s u r e , t h e b u r n t zone has t o expand by a r a d i u s change - A r • P r o p a g a t i o n s p e e d i s t h e n ( A Z.+ A r )/ A t = u . The e x p a n s i o n f a c t o r e = u / u g i v e s an D e p p t i n d i c a t i o n of t h e r e l a t i v e i m p o r t a n c e of p r o p a g a t i o n r a t e u P v e r s u s b u r n i n g r a t e u^ . C a l c u l a t i o n d e t a i l s and computer program a r e g i v e n i n A p p e n d i x C. c) r e s u l t s E x p e r i m e n t s by Lee e t a l [ 2 6 ] , a t a f i x e d e n g i n e s p e e d of 1800 rpm, have shown t h a t t h e maximum power p r o d u c e d by methane i s a p p r o x i m a t e l y 10% l e s s t h a n g a s o l i n e . T h i s number was u s e d t o d e t e r m i n e t h e v a l u e of t h e m u l t i p l i c a t i o n f a c t o r K f o r t h e t u r b u l e n t f l a m e s p e e d m o d e l . In s i m u l a t i o n t e s t s f o r methane, K was a d j u s t e d t o g i v e 10% l e s s power t h a n t h e s i m u l a t i o n w i t h g a s o l i n e . 25 W i t h t h i s v a l u e s e t , a p a r a m e t e r s t u d y was p e r f o r m e d f o r b o t h f u e l s v a r y i n g a i r - f u e l r a t i o , i g n i t i o n t i m i n g and c o m p r e s s i o n r a t i o . The f o l l o w i n g r e s u l t s i n d i c a t e what t h e i n f l u e n c e o f f i n i t e f l a m e s p e e d i s on e n g i n e p e r f o r m a n c e . Fig.6 shows t h e s p e c i f i c f u e l c o n s u m p t i o n v e r s u s a i r - f u e l r a t i o f o r d i f f e r e n t v a l u e s o f t h e i g n i t i o n t i m i n g . One can s e e t h a t t h e i g n i t i o n t i m i n g becomes r e l a t i v e l y u n i m p o r t a n t a t r i c h m i x t u r e s but needs a c c u r a t e s e t t i n g f o r l e a n a i r - f u e l r a t i o s . T h i s i s i n agreement w i t h a c t u a l e n g i n e p e r f o r m a n c e , hence l i m i t e d f l a m e s p e e d i s t h e b a s i s f o r t h i s phenomenon. I t i s o b v i o u s t h a t f u e l c o n s u m p t i o n i s d i r e c t l y r e l a t e d t o power o u t p u t . T h e r e f o r e , power as a f u n c t i o n of a i r - f u e l r a t i o shows l a r g e f l u c t u a t i o n s when i g n i t i o n t i m i n g i s changed F i g . 7 . Comparing i g n i t i o n t i m i n g f o r b e s t f u e l c o n s u m p t i o n f o r methane and g a s o l i n e , i t i s shown i n F i g . 8 t h a t a methane f u e l has t o be i g n i t e d 1 0 ° e a r l i e r t h a n g a s o l i n e f o r l e a n a i r - f u e l r a t i o s . The t i m i n g a t r i c h m i x t u r e s i s not i m p o r t a n t as e x p l a i n e d i n t h e p r e v i o u s r e s u l t s . An i m p o r t a n t p a r a m e t e r f o r f l a m e p r o p a g a t i o n s t u d i e s i s t h e e x p a n s i o n r a t i o e =u /u . I f v a l u e s f o r t h i s f a c t o r a r e p t known, i t can be u s e d t o c a l c u l a t e t h e b u r n i n g s p e e d u^ _ f r o m e x p e r i m e n t a l p r o p a g a t i o n s p e e d d a t a . A d e s c r i p t i o n of f a c t o r s i n f l u e n c i n g t h e e x p a n s i o n r a t i o i s f u r t h e r g i v e n . W i t h t h e s p a r k l o c a t i o n c l o s e t o t h e c y l i n d e r w a l l , a t t h e 26 s i d e of t h e e n g i n e head, t h e f l a m e has o n l y one d i r e c t i o n t o expand so t h a t t h e e x p a n s i o n t e r m i n t h e p r o p a g a t i o n s p e e d i s l a r g e r t h a n f o r a geometry w i t h a c e n t r a l s p a r k e l e c t r o d e . A t h e o r e t i c a l model f o r t h e l a t t e r i s r e a d i l y made s i n c e t h e s p h e r i c a l e x p a n d i n g f l a m e f r o n t keeps i t s c e n t e r i n t h e m i d d l e of t h e c o m b u s t i o n chamber. F o r a s p a r k p l u g n e a r t h e c y l i n d e r w a l l , t h e f l a m e shape i s c o n s t r a i n e d by t h e c u r v e d shape of t h e w a l l and t h e p r e f e r e n t i a l d i r e c t i o n f o r e x p a n s i o n depends on t h e gas m o t i o n k i n e t i c s . T h i s a s p e c t i s i m p o r t a n t but d i f f i c u l t t o s i m u l a t e . Heat t r a n s f e r w i l l t e n d t o l o w e r t h e c o m b u s t i o n t e m p e r a t u r e and p r e s s u r e so t h a t t h e f l a m e has t o expand l e s s i n o r d e r t o o b t a i n u n i f o r m p r e s s u r e i n t h e c y l i n d e r . T h i s w i l l l o w e r t h e e x p a n s i o n r a t i o , e s p e c i a l l y i n t h e e a r l i e r s t a g e of t h e c o m b u s t i o n where h e a t t r a n s f e r i s r e l a t i v e l y i m p o r t a n t . In c h a p t e r I I . 3 c on e n g i n e c o m b u s t i o n p a r a m e t e r s , t h e d i f f e r e n t s t a g e s i n c o m b u s t i o n were e x p l a i n e d n o t i n g t h a t t h e r e i s an i n i t i a l s t a g e where t h e p r e s s u r e i s t h e same as t h e c o m p r e s s i o n p r e s s u r e . T h i s i s o n l y p o s s i b l e i f t h e u n b u r n t m i x t u r e i s not c o m p r e s s e d by t h e e x p a n s i o n o f t h e b u r n t z o n e . The p r o p a g a t i o n s p e e d i s t h e r e f o r e e q u a l t o t h e b u r n i n g s p e e d and e=1. The b u r n t zone i n t h e c y l i n d e r i s s e p a r a t e d from t h e u n b u r n t zone by t h e f l a m e f r o n t . E x p a n s i o n of t h e b u r n i n g f r a c t i o n c a u s e s c o m p r e s s i o n of .-the u n b u r n t as w e l l as t h e b u r n t zone. An a d i a b a t i c c o m p r e s s i o n can be assumed i n a t h e o r e t i c a l model and t h e p r e s s u r e change depends on t h e r a t i o of dV/V of 27 e a c h zone, dV b e i n g t h e volume change due t o t h e c o m p r e s s i o n . In t h e e a r l y c o m b u s t i o n s t a g e , t h e u n b u r n t zone i s v e r y l a r g e so t h a t dV i s a l s o h i g h f o r a c e r t a i n p r e s s u r e change. The b u r n i n g f r a c t i o n expands t o w a r d s t h e u n b u r n t z o n e . At t h e end o f t h e c o m b u s t i o n , t h e d i r e c t i o n o f e x p a n s i o n i s more t o w a r d s t h e b u r n t z o n e . T h i s e x p l a i n s why e w i l l t e n d t o d e c r e a s e as t h e f l a m e p r o c e e d s . W i t h d e v e l o p i n g c o m b u s t i o n , c y l i n d e r p r e s s u r e and u n b u r n t gas d e n s i t y i n c r e a s e . F o r a c e r t a i n r a d i u s change A r of t h e b b u r n t z o n e , t h e amount of f u e l b u r n t i s t h e n h i g h e r , g i v i n g h i g h e r c o m b u s t i o n p r e s s u r e s , or i n o r d e r t o o b t a i n u n i f o r m c y l i n d e r p r e s s u r e , a l a r g e r e x p a n s i o n term A r . T h e r e f o r e , t h i s e e f f e c t w i l l t e n d t o i n c r e a s e t h e e x p a n s i o n r a t i o s i g n i f i c a n t l y i n t i m e , e x c e p t a t t h e b e g i n n i n g , where the c y l i n d e r p r e s s u r e does not change v e r y f a s t . Heat t r a n s f e r was not i n c l u d e d i n t h e s i m u l a t i o n m o d e l . The e x p a n s i o n r a t i o e was c a l c u l a t e d f o r d i f f e r e n t a i r - f u e l r a t i o s f o r an e n g i n e w i t h c e n t r a l s p a r k p l u g and f o r a s p a r k p l u g 20mm from t h e c y l i n d e r w a l l . T h i s l a s t c o n f i g u r a t i o n was u s e d i n t h e e n g i n e e x p e r i m e n t s . R e s u l t s a r e shown i n F i g . 9 and F i g . 1 0 . The e f f e c t o f d e c r e a s i n g and i n c r e a s i n g e x p a n s i o n r a t i o , as e x p l a i n e d b e f o r e , i s f o u n d back i n t h e s e r e s u l t s . The e x p a n s i o n r a t i o d e c r e a s e s w i t h a i r - f u e l r a t i o b e c a u s e of t h e l o w e r c a l o r i f i c f u e l c o n t e n t p e r u n i t c y l i n d e r volume A V. An i n t e r e s t i n g p o i n t f o u n d h e r e 28 i s t h a t t h e e x p a n s i o n r a t i o i s minimum between 10° and 15° b e f o r e TDC, f o r a l l t h e a i r f u e l r a t i o s . T h i s minimum v a l u e of e d i f f e r s from c a s e t o c a s e . 2 9 Fig. 6 : s p e c i f i c fuel consumption J 1 1 1 l 1 i i i • i L 0.8 1.0 1 2 1 4 re la t i ve a i r - f u e l ra t io X 45 40 35 y 30 25 20 15 ign i t ion timing degrees BTDC 0.8 methane gasoline Fig.8 MBT timing CR=8 2000 rpm 1.0 1.2 1.4 r e l a t i v e a i r - f u e l ra t io X optimal i g n i t i o n timing 30 expansion ratio e methane central spark plug MBT timing CR=8 2000 rpm X = 1.3 X = 1.2 \=1.0 X-l.l Fig.10: simulation of expansion r a t i o (central spark plug) -60 -40 -20 TDC 20 degrees crankshaft 31 V. EXPERIMENTAL DESIGN V. 1 O b j e c t i v e The major f a c t o r s t o be s t u d i e d e x p e r i m e n t a l l y i n a d u a l f u e l e n g i n e a r e power o u t p u t , e x h a u s t e m i s s i o n s , e q u i v a l e n c e r a t i o l i m i t s and e f f i c i e n c y . T h e s e a r e g l o b a l e n g i n e p e r f o r m a n c e d a t a . They a r e s t r o n g l y r e l a t e d t o t h e c o m b u s t i o n p r o c e s s . C y c l e - t o - c y c l e v a r i a b i l i t y and f l a m e s p e e d a r e two f a c t o r s o f t h e c o m b u s t i o n p r o c e s s t h a t c a n n o t be c a l c u l a t e d and s h o u l d be i n v e s t i g a t e d e x p e r i m e n t a l l y f o r a d u a l f u e l s t u d y . a) i o n i z a t i o n p r o b e s Flame i o n i z a t i o n p r o b e s or Langmuir p r o b e s were u s e d t o d e t e c t t h e f l a m e p o s i t i o n i n t h e e n g i n e as a f u n c t i o n of t i m e . Flame p r o p a g a t i o n s p e e d i s d e r i v e d f r o m t h e s e d a t a , but i n o r d e r t o c a l c u l a t e f l a m e s p e e d , one needs t o know t h e e x p a n s i o n r a t i o e w h i c h i s t h e r a t i o of t h e p r o p a g a t i o n s p e e d u^ t o t h e t u r b u l e n t f l a m e speed u . C u r r y [5] o b t a i n e d , u s i n g i o n i z a t i o n p r o b e s l o c a t e d i n t h e c y l i n d e r head and p i s t o n , a t h r e e - d i m e n s i o n a l p i c t u r e of t h e f l a m e f r o n t p r o p a g a t i n g t h r o u g h t h e c y l i n d e r . W h i l e most i n v e s t i g a t o r s o n l y r e c o r d t h e a r r i v a l t i m e a t t h e i o n p r o b e , A r r i g o n i e t a l [4] a l s o measured t h e i o n i z a t i o n i n t e n s i t y t o d i s t i n g u i s h t h e s t r u c t u r e o f a t u r b u l e n t f l a m e from t h a t of a 32 l a m i n a r f l a m e . In t h i s work, t h e i o n i z a t i o n p r o b e was u s e d o n l y as a f l a m e p o s i t i o n d e t e c t o r . b) p r e s s u r e measurements P r e s s u r e t r a n s d u c e r s a r e most u s e f u l f o r c o m b u s t i o n s t u d i e s . C o m b u s t i o n d u r a t i o n i s of p r i m a r y i m p o r t a n c e and i t i s d e r i v e d f r o m c y l i n d e r p r e s s u r e v a l u e s u s i n g an e x t e n s i v e computer program, l i k e t h e model d e v e l o p e d by Borman e t a l [ 3 7 ] . T h e r e f o r e , a f a s t d a t a a c q u i s i t i o n s y s t e m i s needed t o r e c o r d and s t o r e t h e p r e s s u r e e v e r y c r a n k a n g l e d e g r e e . R a t h e r , t h e peak p r e s s u r e and t h e t i m e when i t o c c u r s were measured o v e r a l a r g e number of c y c l e s , t y p i c a l l y 400. A n o t h e r i m p o r t a n t p a r a m e t e r i s t h e i n d i c a t e d mean e f f e c t i v e p r e s s u r e ( i m e p ) . A d i r e c t means f o r c a l c u l a t i n g t h e imep was d e v e l o p e d w i t h o u t s t o r a g e of t h e p r e s s u r e d a t a . In t h i s way, a l a r g e sample c o u l d be t a k e n f o r s t u d y of c y c l e - t o -c y c l e v a r i a t i o n . V.2 A p p a r a t u s  a) e n g i n e The e n g i n e u s e d f o r t h i s work was a s i n g l e c y l i n d e r , a i r c o o l e d , o v e r h e a d v a l v e K o h l e r e n g i n e . G e n e r a l s p e c i f i c a t i o n s of t h e e n g i n e a r e g i v e n i n T a b l e I and t h e e n g i n e i s shown i n F i g . 1 2 . 33 T a b l e I : E n g i n e S p e c i f i c a t i o n s model K o h l e r K361 bo r e 95mm s t r o k e 83mm d i s p l a c e m e n t 588cc c o m p r e s s i o n r a t i o 8: 1 power (3600 rpm) I 3 . 4 k w c o n r o d l e n g t h 1 34.9mm The v e n t u r i - t y p e c a r b u r e t o r was r e p l a c e d by a Bosc h f u e l i n j e c t o r and t h e a i r f l o w was measured by a i o n - f l o w a i r meter, c o n n e c t e d t o t h e e n g i n e i n t a k e by a f l e x i b l e h o s e . T h i s i o n -f l o w meter measures i n s t a n t a n e o u s a i r f l o w and t h e a v e r a g e i s o b t a i n e d by i n t e g r a t i o n of t h e s i g n a l o v e r one c y c l e . Methane f l o w was measured by a gas r o t a m e t e r . The e n g i n e was e q u i p p e d w i t h a 2° c r a n k a n g l e d i v i s i o n d i s k , c o n t a i n i n g t o p and bott o m dead c e n t e r marks. A c a p a c i t i v e d i s c h a r g e CD i g n i t i o n s y s t e m was u s e d i n c o n n e c t i o n w i t h an e l e c t r o n i c s y s t e m t o s e t t h e i g n i t i o n t i m i n g . b) e n g i n e i n s t r u m e n t a t i o n The s t u d y o f t h e c o m b u s t i o n p r o c e s s i n t h e c y l i n d e r r e l i e s on t h e use of a p r e s s u r e t r a n s d u c e r and i o n p r o b e s a s f l a m e d e t e c t o r s . An AVL 8QP500c t r a n s d u c e r was u s e d f o r p r e s s u r e 3 4 measurements combined w i t h a Model 504A R i s t l e r c h a r g e a m p l i f i e r . S e v e r a l a u t h o r s d i s c u s s e d t h e p r e p a r a t i o n methods n e c e s s a r y f o r a c c u r a t e r e a d i n g s : Brown [38] and L a n c a s t e r e t a l [ 3 9 ] . L a n c a s t e r e t a l showed t h a t a phase e r r o r of 0.3° c r a n k a n g l e between t h e t o p dead c e n t e r s i g n a l and t h e e x a c t t i m i n g , p r o d u c e s a 1% e r r o r i n i n d i c a t e d mean e f f e c t i v e p r e s s u r e ( i m e p ) . The a c c u r a c y of t h e t o p dead c e n t e r mark on t h e c o u n t i n g d i s k was e s t i m a t e d t o be l e s s t h a n 1° c r a n k a n g l e . However, t h e imep r e s u l t s were compared r e l a t i v e t o e a c h o t h e r and t h e a b s o l u t e v a l u e was of l e s s i m p o r t a n c e . S i n c e t h e p h a s i n g e r r o r i s c o n s t a n t , t h e e x p e c t e d e r r o r of 3% i n imep was a c c e p t a b l e . The t r a n s d u c e r was f l u s h mounted w i t h t h e e n g i n e head w a l l and c o a t e d w i t h RTV r u b b e r t o r e d u c e t h e r m a l s t r a i n [38] [ 3 9 ] . A f t e r a s e t of e x p e r i m e n t s , w h i c h e a c h l a s t e d f o r a b o u t t h r e e h o u r s , t h e c o a t i n g was i n s p e c t e d as i t b u r n s o f f e a s i l y when u s e d on a f l u s h mounted t r a n s d u c e r . I t was n o t i c e d t h a t t h i s p r o b l e m was l e s s s e v e r e when u s i n g methane f u e l , p r o b a b l y due t o t h e l o w e r c o n t e n t i n t h e gas m i x t u r e of c a r b o n p a r t i c l e s w h i c h b r i t t l e t h e r u b b e r c o a t i n g . The t r a n s d u c e r was c o o l e d w i t h w a t e r a t c o n s t a n t s u p p l y p r e s s u r e f o r b e s t r e s u l t s . The p r e s s u r e r e a d i n g a t b o t t o m dead c e n t e r BDC a f t e r t h e i n t a k e s t r o k e was t a k e n as r e f e r e n c e p o i n t , e q u a l t o m a n i f o l d p r e s s u r e . L a n c a s t e r e t a l [39] showed t h a t t h e t i m e c o n s t a n t of t h e s y s t e m f o r t h e d e c a y of t h e e l e c t r i c a l c h a r g e s h o u l d be between 1 sec and 100 s e c . S h o r t e r 35 t i m e c o n s t a n t s g i v e e r r o r s i n t h e p r e s s u r e measurement and l o n g e r t i m e c o n s t a n t s may c a u s e s i g n a l d r i f t . A v a l u e o f 20 s e c or 50 sec was u s e d i n t h e p r e s e n t e x p e r i m e n t s . The method of u s i n g i o n i z a t i o n or Langmuir p r o b e s f o r f l a m e d e t e c t i o n i s e x p l a i n e d i n F i g . 1 1 . F i v e p r o b e s were f i t t e d i n t h e c y l i n d e r head and F i g . 1 3 shows t h e i r r e l a t i v e p o s i t i o n . The p r o b e s were not c o o l e d and would b u r n away i f t h e y were n o t f l u s h w i t h t h e w a l l . However, f l a m e q u e n c h i n g on t h e w a l l t h e n gave l e s s a c c u r a t e r e s u l t s s i n c e t h e f l a m e f r o n t i s a l r e a d y p a s t t h e p r o b e when t h e i o n i z a t i o n a t t h e probe, r i s e s . A c o m p l e t e d i s c u s s i o n o f t h e e r r o r s a f f e c t i n g t h e r e s u l t s i s g i v e n i n c h a p t e r V I . c) d a t a a c q u i s i t i o n s y s t e m The f l o w c h a r t of t h e d a t a a c q u i s i t i o n s y s t e m i s g i v e n i n F i g . 14. The i n p u t s i g n a l s f o r t h e s y s t e m a r e : c r a n k a n g l e d e g r e e p u l s e s w i t h bottom dead c e n t e r mark, i o n p r o b e s i g n a l s and t h e p r e s s u r e s i g n a l . The o u t p u t s i g n a l s a r e i n d i c a t e d on t h e r i g h t of F i g . 1 4 . The s y s t e m i s v e r y s u i t a b l e f o r c y c l e - t o - c y c l e v a r i a t i o n s t u d y as a l l s i g n a l s a r e p r o c e s s e d d u r i n g t h e e x p e r i m e n t and t h e o u t p u t s i g n a l s a r e c a l c u l a t e d f o r e a c h c y c l e . An e i g h t -t r a c k p a p e r r e c o r d e r was u s e d t o s t o r e t h e r e s u l t s . The d r a w i n g s of t h e e l e c t r o n i c c i r c u i t s a r e g i v e n i n A p p e n d i x G. Note t h a t t h e r e a r e two i n t e g r a t i o n c i r c u i t s f o r 36 c a l c u l a t i n g t h e imep i n o r d e r t o d i s p l a y t h e work from t h e pumping l o s s and from t h e f i r i n g s t r o k e s e p a r a t e l y . T y p i c a l r e s u l t s o f t h e sys t e m a r e shown i n F i g . 1 5 t o 18. V.3 T e s t C o n d i t i o n s In t h i s p a r a g r a p h , t h e e n g i n e c o n t r o l p a r a m e t e r s and t h e a c t u a l m e asured v a l u e s a r e d e s c r i b e d . A l i s t i s g i v e n i n T a b l e I I o f t h e t e s t c o n d i t i o n s i n t h e d i f f e r e n t e x p e r i m e n t s t o g e t h e r w i t h t h e i r c o d e number. a) i n d e p e n d e n t p a r a m e t e r s e t t i n g i g n i t i o n t i m i n g : t h e t i m i n g c o u l d be v a r i e d o v e r a wide r a n g e i n d e p e n d e n t of th e o t h e r e n g i n e c o n t r o l s e t t i n g s , s p a r k p l u g : t h r e e d i f f e r e n t p l u g s were t e s t e d i n o r d e r t o see whether t h e power of t h e e n g i n e , r u n n i n g on methane, c o u l d be i m p r o v e d . The s t a n d a r d p l u g had a gap of 0.035 i n c h e s . T e s t s were done w i t h a 0.055 i n c h gap and w i t h a m u l t i -e l e c t r o d e NGK s p a r k p l u g , t h r o t t l e p o s i t i o n : t h e p o s i t i o n i s s p e c i f i e d by t h e amount o f a i r f l o w r e l a t i v e t o t h e maximum a t wide open t h r o t t l e (WOT). T e s t s were done a t WOT and a t 65% of t h e maximum a i r f l o w 37 o b t a i n e d a t t h a t e n g i n e s p e e d , r e l a t i v e a i r - t o - f u e l r a t i o x : th e a i r f l o w was measured and t h e f u e l f l o w was a d j u s t e d a c c o r d i n g l y i n o r d e r t o g e t a c e r t a i n X. V a l u e s r a n g e from 0.9 t o 1.3. e n g i n e s p e e d : a water dyno b r a k e was u s e d as t h e e n g i n e l o a d and i t was a d j u s t e d t o o b t a i n a c e r t a i n e n g i n e s p e e d . b) m easured v a l u e s i o n p r o b e s : t h e t i m e of t h e f l a m e a r r i v a l a t t h e p r o b e was r e c o r d e d f o r p r o b e 1,2 and 3 ( s e e F i g . 1 3 ) . T h i s t i m e i s d e s i g n a t e d as *1'*2 a n < ^ *3* ^ e s u l t s a r e g i v e n i n c r a n k a n g l e d e g r e e s a f t e r i g n i t i o n . moment of peak p r e s s u r e T : PP t h i s i s t h e t i m e of t h e o c c u r e n c e of t h e peak p r e s s u r e and r e s u l t s a r e g i v e n i n c r a n k a n g l e d e g r e e s a f t e r t o p dead c e n t e r . peak p r e s s u r e p : P r e s u l t s g i v e n i n b a r s ( 1 b a r = 1 0 5 P a ) . e n g i n e s p e e d : e n g i n e s p e e d i s r e c o r d e d c o n t i n u o u s l y . i n d i c a t e d mean e f f e c t i v e p r e s s u r e : imep i s t h e c y c l e i n t e g r a l o f pdV and i s c a l c u l a t e d d u r i n g 360° c r a n k a n g l e r o t a t i o n . When t h i s i s f i n i s h e d , i t t r a n s m i t s t h e r e s u l t t o t h e o u t p u t and i m m e d i a t e l y s t a r t s 38 t o i n t e g r a t e t h e n e x t c y c l e . c ) t e s t c o n d i t i o n s A l i s t of t h e i n d e p e n d e n t p a r a m e t e r s e t t i n g s f o r a l l e n g i n e e x p e r i m e n t s i s g i v e n i n T a b l e I I . I (ion probe current) F i g . 1 1 : i o n i z a t i o n p r o b e p r i n c i p l e When the flame arrives at the ion probe, the mixture is ionized and can conduct a current when a voltage is applied to the probe. Wall quenching of the flame w i l l delay the signal 3 9 T a b l e I I : T e s t C o n d i t i o n s e x p e r i m e n t c o d e : M=methane G = g a s o l i n e P 3 5 = s t a n d a r d s p a r k p l u g 0.035 i n c h gap P 5 5 = s t a n d a r d s p a r k p l u g 0.055 i n c h gap • N G K = m u l t i - e l e c t r o d e NGK s p a r k p l u g e x p e r iment s p e e d a i r - f u e l t h r o t t l e i g n i t i o n c ode rpm r a t i o p o s i t i o n % t i m i n g °BTDC M1.A P35 2500 1 .0 100 30 M1.B P35 2500 1 .0 100 35 M1.C P35 2500 1 .0 1 00 35 M1.D P35 2500 0 . 9 100 35 M1.E P35 2500 1 .3 100 45 M1.F P35 2500 1 . 1 1 00 40 M1.G P35 2500 1 .2 1 00 40 M1.H P35 2500 1 .2 1 00 45 M1.I P35 2500 1 .2 1 00 35 M1.J P35 2500 1 .0 65 35 M1.K P35 2500 1 . 1 65 35 M1.L P35 3000 ' 1.0 1 00 40 M1.M . P35 3000 1 . 1 1 00 40 M1.N P35 3000 1 . 2 1 00 45 M1.0 P35 •3000 1.3 1 00 45 M1.P P35 3000 0 . 9 100 35 M1.Q P35 1800 1 .0 1 00 35 G2.1 P35 2500 1 .0 1 00 25 G2.2 P35 2500 0 . 9 100 25 G2.3 P35 2500 1 . 1 1 00 30 G2.4 P35 3000 1 .0 1 00 30 G2.5 P35 1800 1 .0 1 00 20 G2.6 P35 2500 1 .0 65 30 G2.7 P35 2500 - 0 . 9 65 30 G2.8 P35 2500 1 . 1 65 30 G 2 . 9 P35 2500 1 . 1 65 35 M3.10 P35 2500 1 . 1 1 00 35 M3.11 P55 2500 1 . 1 100 35 M3.12 P55 2500 1 . 1 1 00 30 M3.13 P55 2500 1 . 1 1 00 40 M3.14 NGK 2500 1 . 1 1 00 35 M3.15 NGK 2500 1 . 1 1 00 40 M3.16 NGK 2500 1 . 1 100 30 M3.17 NGK 2500 1 . 1 65 35 M3.18 P55 2500 1 . 1 65 35 M3.19 P55 2500 1 . 1 65 40 M3.20 P55 2500 1 . 1 65 30 M3.21 P35 2500 1 . 1 65 35 M3.22 P35 2500 1 . 1 65 40 M3.23 P35 2500 1 . 1 65 30 M3.24 P35 2500 1 . 1 100 35 M3.25 P35 2500 1 . 1 100 40 M3.26 P35 2500 1 . 1 100 30 40 Fig.13 : c y l i n d e r head (64% of o r i g i n a l s i z e ) counter 0-360 reset — T CA degree binary CA degree pulses BDC cylinder head pressure transducer i Kistler 504A charge amp. ] r~ -1^ EPROM d«„. , D/A ~ i J J latch s D/A "\ D/A J latch J J latch * D/A —J J latch s D/A — - J V J EPROM * D/A i dV • X ndV 7 PLL dot It do< dt peak 1 sample detector hold -o ion probe 1 -o I 2 ion probe 2 -o ion probe 3 -o T moment of peak p p pressure -o V cylinder volume dV -o p-j^ work pdV done per degree crankangle -o imep indicated mean effective pressure dcx -o dt engine speed -o Pp peak pressure _Q p cylinder pressure F i g 14 : data a c q u i s i t i o n system A iui typical ion probe signal; trace starts at moment of ignit ion; arrival time shows large variance peak pressure is shown for a number of cycles F i g . 1 5 : i o n probe s i g n a l s F i g . 1 6 : peak p r e s s u r e s i g n a l s cylinder pressure signal; variation of peak pressure from cycle to cycle pressure-volume (p-V) diagrams for three consecutive cycles F i g . 1 7 : c y l i n d e r p r e s s u r e development it* F i g . 1 8 : pressure-volume diagram M 4 3 V I . DATA ANALYSIS VI .1 O b j e c t i v e F o r a l l t h e e x p e r i m e n t s d e s c r i b e d i n T a b l e I I , d a t a from a l a r g e number of c y c l e s were r e c o r d e d i n o r d e r t o p r o v i d e s u f f i c i e n t i n f o r m a t i o n on t h e c o m b u s t i o n phenomena and t h e i r v a r i a b i l i t y . D i f f e r e n t e x p e r i m e n t s have t o be compared so t h a t t h e l a r g e d a t a sample f o r e a c h s i g n a l i s r e d u c e d t o s i n g l e numbers by s t a t i s t i c a l a n a l y s i s . The n o r m a l p r o c e d u r e i s t o t a k e sample a v e r a g e and s t a n d a r d d e v i a t i o n . Whether t h i s i s t h e b e s t method i n t h e p r e s e n t c a s e , or whether o t h e r s t a t i s t i c a l p a r a m e t e r s y i e l d b e t t e r i n f o r m a t i o n was i n v e s t i g a t e d . VI . 2 D a t a R e c o r d i n g and D i g i t i z i n g A l i s t o f t h e r e c o r d e d s i g n a l s i s g i v e n i n c h a p t e r V . 3 a . U s i n g an e i g h t t r a c k p a p e r r e c o r d e r , t h e s i g n a l s r e s u l t i n g from a s p e c i f i c e n g i n e c y c l e have a f i x e d p o s i t i o n on t h e p a p e r , r e l a t i v e t o e a c h o t h e r . T h i s made i t p o s s i b l e t o s t u d y t h e c o r r e l a t i o n between them. Due t o t h e l a r g e amount of d a t a , t h e s i g n a l s on t h e r e c o r d e r o u t p u t were d i g i t i z e d f o r computer u s e . C a r e was t a k e n 4 4 t h a t t h e c o r r e l a t i o n between s i g n a l s was not l o s t . An example of t h e r e c o r d e d d a t a i s g i v e n i n F i g . 1 9 f o r e x p e r i m e n t M1.L. D u r i n g t h e e x p e r i m e n t s , c a r b o n a c c u m u l a t e d a r o u n d t h e i o n i z a t i o n p r o b e t i p , b r e a k i n g down t h e i s o l a t i o n between t h e p r o b e w i r e and e n g i n e g r o u n d . T h i s o c c u r r e d much f a s t e r d u r i n g e x p e r i m e n t s w i t h g a s o l i n e t h a n w i t h methane so t h a t a f t e r a few h o u r s , o p e r a t i o n became i m p o s s i b l e and t h e d e p o s i t s had t o be s c r a p e d o f f . Lean m i x t u r e s p r e s e n t e d a n o t h e r p r o b l e m . The i o n i z a t i o n l e v e l was so low t h a t t h e t r i g g e r i n g c i r c u i t became i n a c t i v e . Even v a r i a b l e t r i g g e r i n g l e v e l d i d n o t s o l v e t h i s p r o b l e m . The r e s u l t , w h i c h can b e . s e e n i n F i g . 2 0 i s t h a t t h e s i g n a l s t a y s c o n s t a n t o v e r a number of c y c l e s . But when i t c h a n g e s , i t i s c e r t a i n t h a t a f l a m e t r i g g e r e d t h e s i g n a l and t h e r e c o r d e d t i m e i s c o r r e c t . O n l y t h o s e p o i n t s were t h e n d i g i t i z e d . A p o s s i b l e e x p l a n a t i o n i s t h a t a t t h e l e a n l i m i t , t h e f l a m e q u e n c h e s on t h e w a l l or t h a t d u r i n g t h e r a p i d e x p a n s i o n of t h e c y l i n d e r volume, t h e f l a m e e x t i n g u i s h e s . The f l a m m a b i l i t y l i m i t of t h e gas m i x t u r e t h e r e f o r e has an e f f e c t on t h e i o n p r o b e s i g n a l s and s h o u l d be s e p a r a t e d from t h e f l a m e s p e e d i n v e s t i g a t i o n . A n o t h e r f a c t o r u n d e r l y i n g t h i s i s t h a t t h e i o n i z a t i o n p r o b e f u r t h e s t from t h e s p a r k p l u g o f t e n showed t h i s e f f e c t , e s p e c i a l l y a t t h e l e a n l i m i t . Few d i f f i c u l t i e s were e n c o u n t e r e d w i t h t h e i o n i z a t i o n p r o b e s w h i c h were more c e n t r a l l y l o c a t e d . T h e r e f o r e t h e s i g n a l was r e c o r d e d o n l y f o r t h e c y c l e s where a f l a m e p r o p a g a t i o n c o u l d be l o c a t e d . The 4 5 c o r r e l a t i o n w i t h o t h e r s i g n a l s i s t h e n l o s t . V I .3 S t a t i s t i c a l A n a l y s i s a) c a l c u l a t e d v a r i a b l e s The v a r i a b l e s c a l c u l a t e d f o r e a c h e x p e r i m e n t a r e : T T I • • 1 l ' 1 2 ' i 3 * f l a m e a r r i v a l t i m e a t i o n i z a t i o n p r o b e 1,2 and 3, measured i n d e g r e e s c r a n k a n g l e a f t e r i g n i t i o n T : PP a r r i v a l t i m e of t h e peak p r e s s u r e , m e a s u r e d i n d e g r e e s c r a n k a n g l e a f t e r t o p d e a d c e n t e r V peak p r e s s u r e i n bar ( l b a r = l 0 5 P a ) imep. : i e i n d i c a t e d mean e f f e c t i v e p r e s s u r e f o r t h e i n t a k e - e x h a u s t s t r o k e , measured i n b a r imep : P i n d i c a t e d mean e f f e c t i v e p r e s s u r e f o r t h e power s t r o k e I : 12 f l a m e t r a v e l t i m e between i o n i z a t i o n p r o b e 1 and 2, measured i n d e g r e e s c r a n k a n g l e . 1-^ 2 * s o b t a i n e d by t a k i n g t h e d i f f e r e n c e between I and I f o r e a c h i n d i v i d u a l c y c l e 1 2 I 23 f l a m e t r a v e l t i m e between i o n i z a t i o n p r o b e 2 and 3 46 b) s t a t i s t i c a l p a r a m e t e r s The q u a l i t y of t h e t o t a l sample of a c a l c u l a t e d v a r i a b l e c a n be i n v e s t i g a t e d by i t s d i s t r i b u t i o n and i t s c o r r e l a t i o n t o o t h e r v a r i a b l e s . T h i s w i l l l e a d t o a d i s c u s s i o n of t h e d i f f e r e n t methods by w h i c h t h e l a r g e sample can be r e d u c e d t o s i n g l e numbers ( e . g . a v e r a g e , s p r e a d ) . These numbers a r e u s e d to' compare t h e d i f f e r e n t e x p e r i m e n t s . The d a t a a n a l y s i s p r o g ram i s l i s t e d i n A p p e n d i x D. d i s t r i b u t i o n F o r e a c h o f t h e c a l c u l a t e d v a r i a b l e s , a r e l a t i v e f r e q u e n c y p o l y g o n o r d i s t r i b u t i o n can be made. R e s u l t s a r e g i v e n i n A p p e n d i x E, F i g . 2 9 t o 48 f o r e x p e r i m e n t M 1 . F . The sample s i z e i s 400. The o r d i n a t e s c a l e i s c h o s e n i n s u c h a way t h a t a u n i f o r m d i s t r i b u t i o n would have a r e l a t i v e f r e q u e n c y o f 1. F i g . 3 6 shows t h a t f o r a number o f c y c l e s , i o n p r o b e 2 r e c e i v e s a s i g n a l e a r l i e r t h an p r o b e 1. N o r m a l l y , t h e o p p o s i t e r e s u l t would be e x p e c t e d s i n c e p r o b e 1 i s c l o s e r t o t h e s p a r k p l u g . The d i s t r i b u t i o n i s n o t v e r y smooth so t h a t a n o t h e r p h y s i c a l e f f e c t , d i f f e r e n t from f l a m e p r o p a g a t i o n , i s p r o b a b l y i n v o l v e d . A p o s s i b l e e x p l a n a t i o n i s w a l l q u e n c h i n g of t h e f l a m e a t p r o b e 1 . M i x t u r e m o t i o n i n t h e c y l i n d e r c o u l d a l s o c a u s e an e a r l y f l a m e a r r i v a l a t p r o b e 2 but t h i s does not e x p l a i n a s e c o n d peak i n t h e d i s t r i b u t i o n o f I s i n c e i t would m e r e l y ^ 12 1 s h i f t t h e t o t a l d i s t r i b u t i o n . From th e e x t e n d e d t a i l end i n t h e d i s t r i b u t i o n of I n ( F i g . 2 9 ) , a p h y s i c a l e f f e c t d i f f e r e n t f r o m 47 f l a m e p r o p a g a t i o n i s i n v o l v e d , i t i s not d e s i r a b l e t o i n c l u d e t h i s i n t h e r e s u l t s t h e r e f o r e a sample a v e r a g e i s n o t recommended as t h e s t a t i s t i c a l method f o r t h e a n a l y s i s . The d i s t r i b u t i o n of ( F i g . 3 7 ) shows t h e same p r o b l e m a l t h o u g h n o t as c l e a r l y as F i g . 3 6 . c o r r e l a t i o n The c o r r e l a t i o n between d i f f e r e n t s i g n a l s g i v e s a d d i t i o n a l q u a l i t a t i v e r e s u l t s ( F i g . 3 8 t o 48 f o r e x p e r i m e n t M1.F). The c y c l e t o c y c l e v a r i a t i o n i s due t o t h e c o m b u s t i o n v a r i a t i o n and can be c h a r a c t e r i z e d by a s u c c e s s i o n o f f a s t and slow burn c y c l e s . A h i g h peak p r e s s u r e i s an i n d i c a t i o n of f a s t b u r n i n g and low peak p r e s s u r e i s t h e r e s u l t of slow b u r n i n g . T h e r e f o r e , peak p r e s s u r e i s w e l l s u i t e d t o r e p r e s e n t t h e c o m b u s t i o n v a r i a t i o n s and i s a p r i m a r y v a r i a b l e f o r c o r r e l a t i o n t e s t s . F i g . 3 8 and 40 show t h a t a s m a l l number o f s i g n a l s from i o n p r o b e 1 do not r e f l e c t t h e same n a t u r e of o r i g i n as t h e b u l k of t h e s a mple. T h i s has a l r e a d y been d i s c u s s e d a b o v e . s t a n d a r d e s t i m a t e s Sample a v e r a g e and s t a n d a r d d e v i a t i o n were c a l c u l a t e d as a f i r s t method of d a t a r e d u c t i o n . A l l c y c l e s were t a k e n i n t o a c c o u n t . T h i s g i v e s l a r g e e r r o r s f o r some s i g n a l s ( s e e i o n p r o b e 1 , F i g . 29.) . 4 8 sample minimum, maximum F o r e a c h c y c l e , minimum and maximum v a l u e s were n o t e d a s an i n d i c a t i o n of t h e d a t a r a n g e . mode v a l u e The mode v a l u e of a sample i s i n d e p e n d e n t of t h e t a i l ends of t h e d i s t r i b u t i o n and would t a k e away t h e e r r o r s p r e v i o u s l y d e s c r i b e d . However, t h e mode v a l u e o n l y c o n t a i n s t h e i n f o r m a t i o n of t h e c l a s s i n t h e h i s t o g r a m w i t h t h e maximum number of d a t a p o i n t s . T h i s i n f o r m a t i o n l o s s o f t h e r e s t o f t h e sample i s n o t a c c e p t a b l e f o r e v e r y c a s e . F i t t i n g a d i s t r i b u t i o n f u n c t i o n t o t h e sample and t h e n t a k i n g t h e mode v a l u e i s b e t t e r . n o r m a l f i t A s i m p l e s o l u t i o n i s f i t t i n g a normal d i s t r i b u t i o n t h r o u g h t h e c e n t r a l p o r t i o n o f t h e r e l a t i v e f r e q u e n c y p o l y g o n f o r e a c h s i g n a l . The c e n t r a l p o r t i o n of t h e d i s t r i b u t i o n i s d e t e r m i n e d as f o l l o w s : s t a r t i n g from t h e t a i l ends of t h e d i s t r i b u t i o n , a t e s t was p e r f o r m e d t o d e t e r m i n e t h e f i r s t c l a s s i n t h e h i s t o g r a m w h i c h has a r e l a t i v e f r e q u e n c y h i g h e r t h a n 60% o f t h e maximum. T h i s t e s t g i v e s a low and a h i g h l i m i t f o r t h e s i g n a l v a l u e . An a v e r a g e and s t a n d a r d d e v i a t i o n was c a l c u l a t e d f o r a l l t h e d a t a w i t h i n t h o s e l i m i t s . T h e s e a r e t h e p a r a m e t e r s f o r t h e no r m a l f i t . D e t e r m i n a t i o n of t h e d a t a l i m i t s d epends o n l y on 49 t h e amount of d a t a i n t h e s e l i m i t c l a s s e s and a l a r g e e r r o r can be e x p e c t e d . The same e r r o r i s r e f l e c t e d i n t h e a v e r a g e s i n c e i t d e p e nds s t r o n g l y on t h e s e l i m i t c a l c u l a t i o n s . q u a n t i l e s V a r i a t i o n s i n t h e t a i l end o f a d i s t r i b u t i o n has no e f f e c t on t h e c e n t r a l q u a n t i l e s . At t h e same t i m e , a c e n t r a l q u a n t i l e depends on t h e i n f o r m a t i o n c o n t a i n e d i n t h e t o t a l sample. C e n t r a l q u a n t i l e s (30, 40, 50, 60 and 70%) were c a l c u l a t e d as w e l l as t h e 15.9% q u a n t i l e . F o r a n o r m a l d i s t r i b u t i o n , t h e d i f f e r e n c e between t h e 15.9% and 50% q u a n t i l e i s e q u a l t o t h e s t a n d a r d d e v i a t i o n . I t was t h e n a l s o an e s t i m a t e f o r t h e sample s p r e a d f o r t h e o b t a i n e d d a t a . c) a n a l y s i s r e s u l t s In A p p e n d i x F, t h e r e s u l t s a r e g i v e n from t h e s t a t i s t i c a l a n a l y s i s f o r a l l e x p e r i m e n t s . The 15.9% and 84.1% q u a n t i l e s a r e i n d i c a t e d w i t h S f o r s t a n d a r d d e v i a t i o n . F o r a l l e x p e r i m e n t s w i t h code M3. , f a i l u r e of t h e g r a p h r e c o r d e r made i t i m p o s s i b l e t o s t o r e t h e peak p r e s s u r e r e s u l t s . 50 50°ATDC 1^: flame a r r i v a l at ion i z a t i o n probe 1 I^: flame a r r i v a l at ion i z a t i o n probe 2 I^: flame a r r i v a l at ion i z a t i o n probe 3 T : a r r i v a l time of PP peak pressure Ppt peak pressure engine speed imep of intake-exhaust stroke imep of power stroke 50°BTDC 50°ATDC 50°BTDC 5 0°ATDC 50°BTDC 50°ATDC Fig.19: experiment Ml.L 0 bar 6.2lbar 51 50°ATDC I j : flame a r r i v a l at ion i z a t i o n probe 1 1.2' flame a r r i v a l at ion i z a t i o n probe 2 1^: flame a r r i v a l at ion i z a t i o n probe 3 T : a r r i v a l time of PP peak pressure p^: peak pressure engine speed imep of intake-exhaust stroke imep of power stroke Fig.20: experiment G2.9 50°BTDC 50°ATDC 50°BTDC 50°ATDC 50°BTDC m 50°ATDC 50°BTDC 0 bar 25 00rpm 52 V I I . DISCUSSION OF EXPERIMENTAL RESULTS  VII.1 I n t r o d u c t i o n a) r e l e v a n t i n f o r m a t i o n d e s c r i p t i o n In t h i s chapter, the r e s u l t s of the s t a t i s t i c a l a n a l y s i s are d i s c u s s e d . U n f o r t u n a t e l y , not a l l of the i n f o r m a t i o n o b t a i n e d g i v e s a c l e a r understanding of the d i f f e r e n c e i n combustion or engine performance when burning e i t h e r methane or g a s o l i n e . For i n s t a n c e , the e f f e c t of d i f f e r e n t spark plugs on engine performance was found to be so s m a l l that the standard d e v i a t i o n i n the s i g n a l s , and the experimental e r r o r make the e f f e c t i m possible to measure. In a d d i t i o n , s h u t t i n g the engine down to change a spark plug r e s u l t e d i n a str o n g d i s c o n t i n u i t y i n experimental procedure which probably i n f l u e n c e d the performance more than the new spark p l u g . In t h i s chapter, a t t e n t i o n i s mainly devoted t o flame propagation and pressure development. b) i n f o r m a t i o n source The experimental study r e l i e d on the use of a pressure transducer and of i o n i z a t i o n probes as flame d e t e c t o r s . 53 The i o n i z a t i o n p r o b e s were u s e d t o s t u d y f l a m e p r o p a g a t i o n . O n l y 1^, I 1 2 a n < 3 I 2 3 a r e d i s c u s s e d a s t h e y g i v e i n f o r m a t i o n on t h e d i f f e r e n t s t a g e s i n t h e c o m b u s t i o n : 1^ i s s t r o n g l y d e p e n d e n t on t h e i g n i t i o n d e l a y w h i l e I - ^ and ! 2 3 9 ^ v e an i n d i c a t i o n of t h e c o m b u s t i o n s p e e d . From t h e p r e s s u r e measurements, imep f o r t h e i n t a k e -e x h a u s t s t r o k e was c a l c u l a t e d . T h i s v a l u e i s needed f o r t h e c a l c u l a t i o n of t h e imep o f t h e t o t a l e n g i n e c y c l e ( f o u r s t r o k e s of t h e p i s t o n ) but i t i s n o t d i s c u s s e d a s a s e p a r a t e r e s u l t . Peak p r e s s u r e and i t s a r r i v a l t i m e and t h e imep of t h e t o t a l e n g i n e c y c l e a r e the major v a r i a b l e s i n t h i s s t u d y f.or d i s c u s s i o n of t h e c o m b u s t i o n . V I I . 2 I o n i z a t i o n P r o b e s  a) i g n i t i o n d e l a y The f l a m e t r a v e l t i m e I between s p a r k p l u g and p r o b e 1 i s an i n d i c a t i o n o f t h e i g n i t i o n d e l a y . E n g i n e t i m i n g f o r maximum power (MBT t i m i n g ) i s s t r o n g l y i n f l u e n c e d by i g n i t i o n d e l a y . In F i g . 2 1 , I i s p l o t t e d f o r b o t h f u e l s a t d i f f e r e n t a i r - f u e l r a t i o s . The methane flame needs on t h e a v e r a g e 36° c r a n k a n g l e t o r e a c h p r o b e 1 w h i l e 29° was f o u n d f o r g a s o l i n e . F o r g a s o l i n e a t A=1.1, a h i g h v a l u e of 39° was f o u n d . The l e a n l i m i t was a p p r o a c h e d a t t h i s a i r - f u e l r a t i o , g i v i n g a s t r o n g l y f l u c t u a t i n g s i g n a l . 54 T e s t s f o r b o t h f u e l s were done a t o p t i m a l t i m i n g (MBT): methane m i x t u r e s a r e i g n i t e d e a r l i e r so t h a t c y l i n d e r p r e s s u r e and u n b u r n t gas t e m p e r a t u r e a r e l o w e r t h a n f o r g a s o l i n e d u r i n g t h e i g n i t i o n d e l a y p e r i o d , hence l o w e r p r o p a g a t i o n s p e e d s . F i g . 2 1 r e p r e s e n t s t h e f l a m e p r o p a g a t i o n under t h e c o n d i t i o n s w h i c h o c c u r i n t h e e n g i n e and c a n n o t be u s e d t o compare t h e f l a m e s p e e d o f g a s o l i n e w i t h t h a t o f methane s i n c e t e m p e r a t u r e and p r e s s u r e c o n d i t i o n s a r e d i f f e r e n t . b) f l a m e s p e e d In c h a p t e r I I I of e n g i n e c a l c u l a t i o n , i t was shown t h a t t h e e x p a n s i o n r a t i o e =u /u has a l a r g e v a r i a t i o n o v e r t h e c o m b u s t i o n p e r i o d and c e r t a i n f a c t o r s , l i k e h e a t t r a n s f e r and s p a r k p l u g l o c a t i o n , i n f l u e n c e t h e e x p a n s i o n r a t i o but a r e d i f f i c u l t t o c a l c u l a t e ( s e e d i s c u s s i o n of f l a m e s p e e d c a l c u l a t i o n c h a p t e r I V . 3 c ) . I t i s t h e r e f o r e v e r y d i f f i c u l t t o o b t a i n f l a m e s p e e d v a l u e s u. from t h e p r o p a g a t i o n speed u t p w h i c h i s measured by t h e i o n i z a t i o n p r o b e s . P r o p a g a t i o n s p e e d of g a s o l i n e c o u l d be l o w e r t h a n of methane but t h e r e v e r s e might be t r u e f o r t h e b u r n i n g s p e e d , due t o a l a r g e d i f f e r e n c e i n e x p a n s i o n r a t i o . F i g . 2 2 f o r t h e f l a m e t r a v e l t i m e between p r o b e 1 and 2 shows t h a t , f o r some a i r - f u e l r a t i o s , t h e p r o p a g a t i o n s p e e d of g a s o l i n e i s l a r g e r t h a n f o r methane w h i l e i t i s l o w e r a t o t h e r a i r - f u e l r a t i o s . No g e n e r a l c o n c l u s i o n can be drawn e x c e p t t h a t t h e p r o p a g a t i o n speeds a r e c o m p a r a b l e i n m a g n i t u d e d u r i n g t h e 5 5 c e n t r a l p o r t i o n of t h e c o m b u s t i o n . From F i g . 2 3 f o r t h e f l a m e t r a v e l between p r o b e 2 and 3 a t d i f f e r e n t a i r - f u e l r a t i o s , i t i s c o n c l u d e d t h a t a g a s o l i n e f l a m e p r o p a g a t e s f a s t e r t h a n methane tow a r d s t h e end o f t h e c o m b u s t i o n . T h e r e seems t o be an e x c e p t i o n a t a r e l a t i v e a i r -f u e l r a t i o A=1.1 but g a s o l i n e a p p r o a c h e d t h e l e a n l i m i t a t t h i s p a r a m e t e r c o n d i t i o n . C a r e s h o u l d be t a k e n when e x a m i n i n g t h e v a l u e s of t h e fl a m e p r o p a g a t i o n t i m e a t l e a n e r m i x t u r e s b e c a u s e of t h e d i f f i c u l t i e s of d e t e c t i n g t h e fl a m e a t p r o b e 3. T h i s was a l r e a d y e x p l a i n e d i n c h a p t e r VI .2. V I I . 3 P r e s s u r e Measurements  a) e n g i n e work The work d e v e l o p e d i n f o u r p i s t o n s t r o k e s or one t o t a l e n g i n e c y c l e i s p r o p o r t i o n a l t o t h e d i f f e r e n c e i n t h e imep f o r the power s t r o k e and t h e i n t a k e - e x h a u s t s t r o k e . T h i s v a l u e i s p l o t t e d v e r s u s a i r - f u e l r a t i o i n F i g . 2 4 . At A=1.0, t h e maximum power o b t a i n e d w i t h g a s o l i n e i s 12% h i g h e r t h a n f o r methane. F i g . 2 4 a l s o shows t h e work d e v e l o p e d w i t h methane a t h i g h e r e n g i n e s p e e d : 3000rpm v e r s u s 2500rpm as s t a n d a r d t e s t c o n d i t i o n . The s t a n d a r d d e v i a t i o n i s a measure of t h e c y c l e - t o - c y c l e power v a r i a t i o n . G a s o l i n e b u r n s f a s t e r t h an methane so t h a t t h e p h a s i n g between p i s t o n m o t i o n and c o m b u s t i o n p r e s s u r e b u i l d - u p 56 i s s m a l l e r . T h i s r e s u l t s i n l e s s v a r i a t i o n i n p r e s s u r e d e v e l o p m e n t . On t h e o t h e r hand, t h e g a s o l i n e f u e l i s l i q u i d , c a u s i n g v a r i a t i o n s i n f u e l d i s t r i b u t i o n . T h e s e two i n f l u e n c e s make i t d i f f i c u l t t o p r e d i c t w h i c h f u e l shows t h e s m a l l e s t c y c l e - t o - c y c l e v a r i a t i o n . The s t a n d a r d d e v i a t i o n i s r e p r e s e n t e d i n F i g . 2 4 by e r r o r b a r s and t h e power v a r i a t i o n i s c o m p a r a b l e f o r b o t h f u e l s a t a r e l a t i v e a i r - f u e l r a t i o A =0.95. b) peak p r e s s u r e F i g . 2 5 shows t h e peak p r e s s u r e as a f u n c t i o n o f a i r - f u e l r a t i o f o r b o t h f u e l s . The peak p r e s s u r e i s h i g h e r f o r g a s o l i n e t h a n f o r methane, due t o i t s h i g h e r f l a m e s p e e d , e x c e p t a t t h e l e a n l i m i t o p e r a t i o n (\=1.1). The s t a n d a r d d e v i a t i o n on t h e peak p r e s s u r e i s g i v e n i n F i g . 2 6 . I t c a n be seen f r o m t h i s f i g u r e t h a t t h e v a r i a t i o n i n peak p r e s s u r e i s s l i g h t l y h i g h e r f o r methane. c ) a r r i v a l t i m e o f peak p r e s s u r e The o c c u r r e n c e t i m e o f t h e peak p r e s s u r e f o r d i f f e r e n t a i r - f u e l r a t i o s i s shown i n F i g . 2 7 . The c u r v e s f o r g a s o l i n e and methane a r e v e r y d i s t i n c t . The peak p r e s s u r e comes l a t e r w i t h g a s o l i n e f o r l e a n e r m i x t u r e s . T h i s i s u n d e r s t a n d a b l e when i t i s c o n s i d e r e d t h a t , i f t h e moment o f peak p r e s s u r e i s c o n s t a n t , a l e a n e r m i x t u r e has t o be i g n i t e d much e a r l i e r . T h i s l o w e r s t h e e n g i n e power. T h i s e x p l a i n s t h e g a s o l i n e c u r v e t a k e n a t b e s t power i g n i t i o n t i m i n g . A n o t h e r f a c t o r i n f l u e n c i n g t h e t i m e o f 57 t h e peak p r e s s u r e i s p i s t o n m o t i o n . At t h e r e l a t i v e l y l o w e r f l a m e s p e e d of a m e t h a n e - a i r m i x t u r e , t h e p i s t o n m o t i o n becomes more i m p o r t a n t . The f l a m e s p e e d i s l o w e r f o r l e a n e r m i x t u r e s so t h a t peak p r e s s u r e comes n e a r e r t o t o p d ead c e n t e r t h a n f o r r i c h e r m i x t u r e s . A n o t h e r way of e x a m i n i n g t h e i n t e r f e r e n c e between p i s t o n m o t i o n and f l a m e s p e e d i s g i v e n i n F i g . 4 6 and F i g . 4 7 . F i g . 4 6 shows a t e s t p e r f o r m e d w i t h g a s o l i n e a t A =0.9. A f a s t f l a m e has a h i g h peak p r e s s u r e w h i c h comes c l o s e t o t o p d ead c e n t e r . A s l o w e r f l a m e needs more t i m e t o d e v e l o p but i s s t i l l s t r o n g enough t o have i t s peak l a t e r i n t h e c o m b u s t i o n . However, l o o k i n g a t F i g . 4 7 (methane a t A = 1 . 3 ) , i t i s seen t h a t i n t h i s c a s e t h e slow f l a m e i s not a b l e t o b u i l d up p r e s s u r e a g a i n s t t h e c y l i n d e r volume e x p a n s i o n , g i v i n g a peak p r e s s u r e c l o s e t o t o p dead c e n t e r s i n c e p i s t o n m o t i o n now has a s t r o n g e r i n f l u e n c e on p r e s s u r e d e v e l o p m e n t . The o c c u r r e n c e t i m e of peak p r e s s u r e t h u s depends on t h e c y l i n d e r volume e x p a n s i o n n e a r TDC. The p r e s s u r e change due t o p i s t o n m o t i o n can be c a l c u l a t e d f r o m t h e f o r m u l a P1/P2 = (V2/V1 ) k = ( 1 + d V / V l ) k where 1 and 2 r e f e r t o d i f f e r e n t p i s t o n p o s i t i o n s . The e x p a n s i o n dV r e l a t i v e t o t h e volume V i s shown i n F i g . 2 8 . I t goes from a low v a l u e a t TDC t o a maximum a t 33° c r a n k a n g l e a f t e r TDC. A t t h e t i m e o f peak p r e s s u r e , t h e p r e s s u r e d r o p due t o p i s t o n m o t i o n and t h e p r e s s u r e r i s e due t o c o m b u s t i o n a r e e q u a l . F i g . 2 7 and 28 show t h a t g a s o l i n e c a n a t t a i n a h i g h e r 58 f l a m e s p e e d than methane s i n c e i t can compensate f o r a l a r g e r volume e x p a n s i o n . 59 Ij ion probe 1 (degrees after ignition) Fig.21: flame t r a v e l time from spark plug to probe 1 I O methane I I 1 1 1 1  0.9 1.0 1.1 1.2 1.3 relative air-fuel ratio X 100? air flow MBT timing 2500 rpm O gasoline O methane Fig.23: flame t r a v e l time between probe 2 and probe 3 1 1 • • 1 • • • • • • !23 (degrees crankshaft) 16 |. 14 0.9 1.0 1.1 1.2 1.3 relative air-fuel ratio \ 60 I imep (bar) (total engine cycle) 24: i n d i c a t e d mean e f f e c t i v e s u r e f o r f o u r s t r o k e e n g i n e ratio X pp peak pressure (bar) F i g . 2 5 : peak p r e s s u r e 1 1 ' 1 1 1  0-9 1.0 1.1 1.2 1.3 relative air-fuel ratio X standard deviation of peak pressure (bar) 100* air flow MBT timing 2500 rpm O gasoline F i g . 2 6 : s t a n d a r d d e v i a t i o n o f t h e peak p r e s s u r e i i i i i i i i i i 0.9 1.0 1.1 1.2 1.3 relative air-fuel ratio X 61 (degrees ATDC) 100% air flow MBT timing Fig.27; a r r i v a l time of the peak pressure 0.9 1.0 1.1 1.2 1.3 relative air-fuel ratio X I cylinder volume expansion I- (dV/V) / (dV/Vl in % Kohler K361 engine after TDC 62 V I I I . CONCLUSIONS AND RECOMMENDATIONS V I I I . 1 G e n e r a l T h e s i s O v e r v i e w The d i f f e r e n c e s i n c o m b u s t i o n o f n a t u r a l gas and g a s o l i n e i n s p a r k - i g n i t i o n e n g i n e s were s t u d i e d . The a n a l y t i c a l and e x p e r i m e n t a l r e s u l t s p r e s e n t e d i n t h i s t h e s i s show t h e e x t e n t t o w h i c h t h e c o m b u s t i o n i n a s p a r k - i g n i t i o n e n g i n e i s i n f l u e n c e d by t h e c a l o r i f i c v a l u e o f t h e f u e l , gas c o m p o s i t i o n and d i s s o c i a t i o n , r e a c t i o n k i n e t i c s a n d f l a m e s p e e d and c y c l e -t o - c y c l e v a r i a t i o n s . A summary of t h e f i n d i n g s i s g i v e n i n t h i s c h a p t e r . N u m e r i c a l s i m u l a t i o n o f e n g i n e p e r f o r m a n c e was u s e d t o e v a l u a t e t h e i n f l u e n c e o f t h e c a l o r i f i c v a l u e and gas c o m p o s i t i o n ( p r o g r a m by Benson e t a l [ 3 ] ) , and t o show q u a l i t a t i v e l y t h e e f f e c t o f f l a m e s p e e d on e n g i n e p e r f o r m a n c e ( p r o g r a m d e s c r i b e d i n A p p e n d i x C ) . R e a l p e r f o r m a n c e d i f f e r e n c e s between n a t u r a l gas and g a s o l i n e were m e a s u r e d i n a s i n g l e c y l i n d e r t e s t e n g i n e , u s i n g t h r e e i o n i z a t i o n p r o b e s and a p r e s s u r e t r a n s d u c e r . Flame a r r i v a l t i m e a t t h e p r o b e s , peak p r e s s u r e a n d i n d i c a t e d mean e f f e c t i v e p r e s s u r e were o b t a i n e d . The v a r i a t i o n from c y c l e t o c y c l e o f t h e c o m b u s t i o n was s t u d i e d by making a s t a t i s t i c a l a n a l y s i s o f t h e measurements from 400 c o n s e c u t i v e c y c l e s . 63 V I I I .2 M a j o r R e s u l t s a) e n g i n e power F o r a s t o i c h i o m e t r i c m i x t u r e (AF=14.8 f o r g a s o l i n e and 17.2 f o r m e t h a n e ) , t h e c a l o r i f i c v a l u e of t h e f u e l p e r kg of a i r i n t h e m i x t u r e i s a p p r o x i m a t e l y t h e same f o r methane (50.5/17.2 M J / k g a i r ) as f o r g a s o l i n e (43.5/14.8 M J / k g a i r ) . In s w i t c h i n g from a l i q u i d f u e l ( g a s o l i n e ) t o methane, t h e r e d u c t i o n i n e n g i n e power due t o t h e r e p l a c e m e n t of a i r by t h e g a s e o u s f u e l a t a g i v e n rpm i s shown by c a l c u l a t i o n t o be a b o u t 9%. Computer c a l c u l a t i o n s of t h e e f f e c t s on power of gas p r o p e r t i e s and d i s s o c i a t i o n of t h e b u r n t g a s e s show a p p r o x i m a t e l y 2.5% h i g h e r e n g i n e e f f i c i e n c y f o r methane a t X=1.0. T h i s would r e d u c e t h e c a l c u l a t e d power l o s s t o 7%. In measurements on t h e s i n g l e c y l i n d e r e n g i n e , i t was f o u n d t h a t t h e o p t i m a l i g n i t i o n t i m i n g f o r methane was 10° e a r l i e r t h a n f o r g a s o l i n e . A 12% power l o s s was measured a t 2500 r p m , X = 1 , wide open t h r o t t l e and o p t i m a l i g n i t i o n t i m i n g . S i m u l a t i o n p r o g r a m s c o n f i r m e d t h e s t r o n g dependence of power and i g n i t i o n a d v a nce on f l a m e s p e e d . S u p p o s i n g e q u a l h e a t t r a n s f e r , i t was the n c o n c l u d e d t h a t t h e d i f f e r e n c e between t h e c a l c u l a t e d 7% power l o s s and t h e measured 12% l o s s c an be a t t r i b u t e d t o t h e l o w e r f l a m e speed of methane. b) c y c l e - t o - c y c l e v a r i a t i o n S t a t i s t i c a l a n a l y s i s of imep c a l c u l a t e d from c y l i n d e r 64 p r e s s u r e - t i m e d a t a showed t h e s t a n d a r d d e v i a t i o n of t h e work was a b o u t 2.5% o f t h e a v e r a g e v a l u e , f o r t h e r e l a t i v e a i r - f u e l r a t i o s X .between 0.9 and 1.0.. A v a l u e o f 2.2% was f o u n d f o r g a s o l i n e . T h e s e measurements showed t h a t power and p r e s s u r e v a r i a t i o n s were n o t c o n s i s t e n t l y l a r g e r f o r one f u e l t h a n t h e o t h e r . A p o s s i b l e e x p l a n a t i o n i s t h a t t h e l o w e r f l a m e s p e e d o f methane i n c r e a s e d power v a r i a t i o n s but t h a t t h i s e f f e c t was c o m p e n s a t e d by i t s b e t t e r f u e l d i s t r i b u t i o n . The e f f e c t s c o u l d n o t be q u a n t i f i e d s e p a r a t e l y . A t t h e same r e l a t i v e a i r - f u e l r a t i o f o r b o t h f u e l s , c y c l e -t o - c y c l e v a r i a t i o n was t h e same w i t h i n t h e e r r o r o f t h e m e asurements. c ) p r e s s u r e d e v e l o p m e n t The a r r i v a l t i m e of t h e peak p r e s s u r e was c l e a r l y d i f f e r e n t f o r g a s o l i n e and methane. F o r e n g i n e t e s t s w i t h g a s o l i n e a t o p t i m a l i g n i t i o n t i m i n g , t h e peak p r e s s u r e i s a s l a t e a s 24.5° ATDC w h i l e 20° ATDC was f o u n d f o r methane. The c y l i n d e r volume e x p a n s i o n r a t e (dV /doO/v i s 0 a t TDC and i s maximum a t 33° ATDC f o r t h i s e n g i n e . At t h e peak p r e s s u r e , t h e p r e s s u r e d r o p due t o p i s t o n m o t i o n c o m p e n s a t e s f o r t h e c o m b u s t i o n p r e s s u r e r i s e . T h i s shows t h a t g a s o l i n e i s a b l e t o a t t a i n h i g h e r c o m b u s t i o n s p e e d s s i n c e t h e peak p r e s s u r e a r r i v e s l a t e r t h a n f o r methane. 65 d) f l a m e p r o p a g a t i o n As i n f e r r e d from t h e s i g n a l s from i o n i z a t i o n p r o b e s , t h e i g n i t i o n d e l a y was 7° l o n g e r f o r methane t h a n f o r g a s o l i n e . T h i s l o n g e r i g n i t i o n d e l a y was t h e r e a s o n t o a d v a n c e t h e t i m i n g t o m a x i m i z e t h e power o u t p u t . T h i s e a r l i e r i g n i t i o n f o r methane r a i s e d t h e p r e s s u r e and t e m p e r a t u r e enough so t h a t t h e f l a m e p r o p a g a t i o n s p e e d was e q u a l f o r b o t h f u e l s d u r i n g t h e c e n t r a l c o m b u s t i o n s t a g e . The l o w e r f l a m e speed o f methane d u r i n g t h e c y l i n d e r volume e x p a n s i o n a f t e r TDC, as i n d i c a t e d by t h e peak p r e s s u r e a r r i v a l t i m e , was c o n f i r m e d by a l o n g e r f l a m e t r a v e l t i m e . B u r n i n g s p e e d c o u l d not be c a l c u l a t e d f r o m t h e measured p r o p a g a t i o n s p e e d s i n c e t h e i r r e l a t i o n s h i p was not known. VI11 . 3 Recommendations  a) equipment improvement D u r i n g t h e e x p e r i m e n t s , i t was f o u n d t h a t w a l l q u e n c h i n g of t h e f l a m e gave s i g n i f i c a n t e r r o r s i n t h e i o n i z a t i o n p r o b e r e s u l t s . T h i s e f f e c t depends v e r y much on f u e l c o n d i t i o n s and v a r i e s t h r o u g h o u t t h e c o m b u s t i o n chamber. I t i s recommended t h a t f o r f u r t h e r e x p e r i m e n t a l s t u d y , i o n i z a t i o n p r o b e s be c o o l e d and n o t f l u s h mounted. A s p a r k p l u g t y p e of i o n p r o b e w h i c h can be s c r e w e d i n t h e c y l i n d e r head, w i l l f u r t h e r improve t h e o p e r a t i o n s i n c e p r o b e c l e a n i n g w i l l n o t r e q u i r e r e m o v a l of t h e c y l i n d e r head. 66 b) r e s e a r c h f i e l d New i n f o r m a t i o n on t h e c y c l e - t o - c y c l e v a r i a t i o n c a n be o b t a i n e d i f v a p o r i z e d g a s o l i n e i s u s e d . F u e l d i s t r i b u t i o n w i l l t h e n be t h e same as f o r methane and c y c l e - t o - c y c l e v a r i a t i o n d i f f e r e n c e s c an be a t t r i b u t e d c o m p l e t e l y t o f l a m e s p e e d . B e t t e r s p a t i a l f l a m e p o s i t i o n measurements c a n be o b t a i n e d i f more i o n i z a t i o n p r o b e s a r e u s e d . Combined w i t h t h e r e c o r d e d p r e s s u r e d u r i n g t h e c o m b u s t i o n , i t i s t h e n p o s s i b l e t o p r e d i c t t h e r e l a t i o n s h i p between p r o p a g a t i o n a n d b u r n i n g f l a m e s p e e d u s i n g s i m u l a t i o n p r o g r a m s . T h i s method w i l l t a k e away any doubt as t o t h e v a l u e o f t h e f l a m e s p e e d . C o r r e l a t i o n w i t h t h e mass b u r n r a t e , c a l c u l a t e d f r o m p r e s s u r e , w i l l p r o v i d e a t h o r o u g h u n d e r s t a n d i n g of t h e c o m b u s t i o n p r o c e s s . 67 REFERENCES [1] G . J . B o r n "The a l t e r n a t e f u e l l e d a u t o m o b i l e (NG and G a s o l i n e ) " , J a n . 1982, u n p u b l i s h e d [2] K . 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P e t e r s , A.A.Quader " W e t t i n g t h e a p p e t i t e of s p a r k -i g n i t i o n e n g i n e s f o r l e a n c o m b u s t i o n " , SAE P a p e r 780234, 1978 [14] H.T.Yu " F u e l d i s t r i b u t i o n s t u d i e s - A new l o o k a t an o l d ' p r o b l e m " , SAE Paper 1963 [15] M . T . O v e r i n g t o n , R . H . T h r i n g " G a s o l i n e e n g i n e c o m b u s t i o n -t u r b u l e n c e and t h e c o m b u s t i o n chamber", SAE P a p e r 810017, 1981 [16] J . N . M a t t a v i "The a t t r i b u t e s o f f a s t b u r n i n g r a t e s i n e n g i n e s " , SAE Paper 800920, 1980 [17] G.G.Lucas, M.Brunt, S . P e t r o v i c "Lean m i x t u r e r u n n i n g of t h e s p a r k - i g n i t i o n e n g i n e by t h e g e n e r a t i o n o f a v o r t e x s y s t e m w i t h i n t h e i n t a k e " , SAE Paper 780964, 1978 [18] R . H . T h r i n g "The e f f e c t s o f v a r y i n g c o m b u s t i o n r a t e i n s p a r k - i g n i t i o n e n g i n e s " , SAE Paper 790387, 1979 [19] G.J.Van Wylen, R.E.Sonntag " F u n d a m e n t a l s o f c l a s s i c a l t h e r m o d y n a m i c s " , W i l e y & S o n s , 1978, p.327 69 [20] E . F . O b e r t " I n t e r n a l c o m b u s t i o n e n g i n e s and a i r p o l l u t i o n " , I n t e x t , 1968, p.166-191 [21] R.S.Benson, W.J.Annand, P.C.Baruah "A s i m u l a t i o n model i n c l u d i n g i n t a k e and e x h a u s t s y s t e m s f o r a s i n g l e c y l i n d e r f o u r - s t r o k e c y c l e s p a r k - i g n i t i o n e n g i n e " , UMIST, 1974 [22] P.N.Blumberg, J.M.Novak " P a r a m e t r i c s i m u l a t i o n of s i g n i f i c a n t d e s i g n and o p e r a t i n g a l t e r n a t i v e s a f f e c t i n g t h e f u e l economy and e m i s s i o n s of s p a r k - i g n i t e d e n g i n e s " , SAE Paper 780943, 1978 [23] E.S.Starkman, H.K.Newhall "Thermodynamic p r o p e r t i e s of methane and a i r , and p r o p a n e and a i r f o r e n g i n e p e r f o r m a n c e c a l c u l a t i o n s " , SAE P a p e r 670466, 1967 [24] A.A.Quader "What l i m i t s l e a n o p e r a t i o n i n s p a r k - i g n i t i o n e n g i n e s - f l a m e i n i t i a t i o n o r p r o p a g a t i o n ? " , SAE Paper 760760, 1976 [25] G.A.Karim, I . A . A l i " C o m b u s t i o n , knock and e m i s s i o n c h a r a c t e r i s t i c s of a n a t u r a l gas f u e l l e d s p a r k - i g n i t i o n e n g i n e w i t h p a r t i c u l a r r e f e r e n c e t o low i n t a k e t e m p e r a t u r e c o n d i t i o n s " , P r o c . I n s t n . M e c h . E n g r s . V o l 189 24/75 [26] R.C.Lee, D.B.Wimmer " E x h a u s t e m i s s i o n abatement by f u e l v a r i a t i o n s t o p r o d u c e l e a n c o m b u s t i o n " , SAE Paper 680769, 1968 [27] M.Pearce " L i q u i d methane as a motor f u e l " , P r o c . A u t o m o b i l e D i v i s i o n , I.Mech.E., 1949-50, p.155 [28] N.P.Moore, B.N.Roy " C o m p a r a t i v e s t u d i e s of methane and p r o p a n e as e n g i n e f u e l s " , P r o c . A u t o m o b i l e D i v i s i o n , I.Mech.E., 1955, p.1157 7 0 [29] K . C h r i s t o p h , W . C a r t e l l i e r i , U . P f e i f e r " D i e Bewertung d e r K l o p f f e s t i g k e i t von K r a f t g a s e n m i t t e l s d e r M e t h a n z a h l und d e r e n p r a k t i s c h e Anwendung b e i Ga s m o t o r e n " , MTZ M o t o r t e c h n i s c h e Z e i t s c h r i f t 33(1972)10 [30] G.A.Karim, M.V.D'Souza "The c o m b u s t i o n of methane w i t h r e f e r e n c e t o i t s u t i l i z a t i o n i n power s y s t e m s " , J o u r n a l of t h e I n s t i t u t e of F u e l , June 1972, p.335 [31] T.W.Ryan, S . S . L e s t z "The l a m i n a r b u r n i n g v e l o c i t y of i s o o c t a n e , n - h e p t a n e , m e t h a n o l , methane, and p r o p a n e a t e l e v a t e d t e m p e r a t u r e and p r e s s u r e s i n t h e p r e s e n c e of a d i l u e n t " , SAE Paper 800103, 1980 [32] G.E.Andrews, D . B r a d l e y "The b u r n i n g v e l o c i t y of methane-a i r m i x t u r e s " , C o m b u s t i o n and Flame 19, 1972, p.275-288 [33] G . T s a t s a r o n i s " P r e d i c t i o n of p r o p a g a t i n g l a m i n a r f l a m e s i n -methane, oxygen, n i t r o g e n m i x t u r e s " , C o m b u s t i o n and Flame 33, 1978, p.217-239 [34] A . M . G a r f o r t h , C . J . R a l l i s "Laminar b u r n i n g v e l o c i t y o f s t o c h i o m e t r i c m e t h a n e - a i r m i x t u r e s : p r e s s u r e and t e m p e r a t u r e d e p e n d e n c e " , C o m b u s t i o n and Flame 31, 1978, p.53-68 [35] M . P . H a l s t e a d , D.B.Pye, C.P.Quinn "Laminar b u r n i n g v e l o c i t i e s and weak f l a m m a b i l i t y l i m i t s under e n g i n e - l i k e c o n d i t i o n s " , C o m b u s t i o n and Flame 22, 1974, p.89-97 [36] D.K.Kuehl " L a m i n a r - b u r n i n g v e l o c i t i e s of p r o p a n e a i r m i x t u r e s " , E i g h t I n t e r n a t i o n a l Symposium on C o m b u s t i o n , p.510 (1962) 71 [37] G.L.Borman, R . B . K r i e g e r "The c o m p u t a t i o n of a p p a r e n t h e a t r e l e a s e f o r i n t e r n a l c o m b u s t i o n e n g i n e s " , ASME 66-WA/DGP-4 [38] W.L.Brown "Methods f o r e v a l u a t i n g r e q u i r e m e n t s and e r r o r s i n c y l i n d e r p r e s s u r e measurement", SAE P a p e r 670008, 1967 [39] D . R . L a n c a s t e r , R . B . K r i e g e r , J . H . L i e n e s c h "Measurement and a n a l y s i s of e n g i n e p r e s s u r e d a t a " , SAE Pa p e r 750026, 1975 [40] R.Bosch " A u t o m o t i v e handbook", V D I - V e r l a g , 1976, p.216-217 72 Ap p e n d i x A. C a l o r i f i c C a l c u l a t i o n s V a l u e s i n t h e c a l c u l a t i o n s a r e t a k e n from r e f . [ 4 0 ] . g a s o l i n e s t o c h i o m e t r i c a i r - f u e l r a t i o = 14.8 kg a i r / k g f u e l c a l o r i f i c v a l u e = 43.5 MJ/kg f u e l A ssuming t h e f u e l i s l i q u i d , t h e e n e r g y c o n t e n t of t h e f u e l i n a s t o c h i o m e t r i c m i x t u r e p e r m 3 c y l i n d e r volume i s ( d e n s i t y p =1.2) E = P X43.5/14.8 = 3.52 MJ/m: methane s t o c h i o m e t r i c a i r - f u e l r a t i o = 17.2 kg a i r / k g f u e l c a l o r i f i c v a l u e = 50.5 MJ/kg f u e l Methane t a k e s a p p r o x i m a t e l y 9% of t h e c y l i n d e r volume so t h a t t h e r e i s o n l y 91% of t h e a i r c o n t e n t o f a g a s o l i n e m i x t u r e E = 0.91Xp X50.5/17.2 = 3.2 MJ/m 3 i s o o c t a n e s t o c h i o m e t r i c a i r - f u e l r a t i o = 15.1 kg a i r / k g f u e l c a l o r i f i c v a l u e = 43.5 MJ/kg f u e l A ssuming i s o o c t a n e i n l i q u i d f o r m and w i t h t h e same c a l o r i f i c v a l u e as g a s o l i n e E = px43.5/15.1=3.45 MJ/m 3 I s o o c t a n e i n g a s e o u s form would t a k e 1.5% of t h e c y l i n d e r volume so t h a t f o r t h i s c a s e E = 3.45x0.985 = 3.4 MJ/m 3 methane d e v e l o p s 9% l e s s power t h a n g a s o l i n e ( l i q u i d ) methane d e v e l o p s 7.5% l e s s power t h a n i s o o c t a n e ( l i q u i d ) methane d e v e l o p s 6% l e s s power t h a n i s o o c t a n e ( g a s e o u s ) Appendix B. Gas Composition Calculations a) methane f u e l l e d engine OTTO CYCLE ANALYSIS PROGRAM 9 10 21 22 25 26 31 32 33 34 35 36 INPUT DATA CYL OIA (M) 0.100 STROKE (H) O.1O0 COMP RATIO BOO AIR FUEL RATIO 17.41 CARBON ATOMS IN FUEL HYDROGEN ATOMS IN FUEL HEAT OF REACTION (J/KG) TRAPPED PRESS (N/M"2) 101325.000 TRAPPED TEMP (K) 298.0 REF PRESS <N/M"2) 101325.000 REF TEMP (K) 298.0 ENGINE SPEED (RPS) 41.7 AIR FUEL RATIO STOICHIOMETRIC 17.238 FUEL AIR EQUIVALENCE 0.990 1 .00 4.00 -50OS0O0O.0 FOLLOWING SPECIES IN PERCENT VOLUME ENERGY (ABSOLUTE) IN J PER KGMOL FUEL 44 STEP V0L(M"3) PRESS(BAR) TEMP(K) C02 CO H20 H2 02 N2 CNHM ENERGY 45 46 1 0 8976E-03 1 013 298 0 0 0 0 0 0 0 0 0 19 022 71 560 9.417 -0 32365E*07 47 2 0 8103E-03 1 167 309 8 0 0 0 0 0 0 0 0 19 022 71 560 9.417 -0 48538E*06 48 3 0 7231E-03 1 365 323 4 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 27088E»07 49 4 0 6358E-03 1 629 339 4 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 64B47E*07 50 5 0 5485E-03 1 995 358 5 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 1 1051E+08 51 6 0 46I3E-03 2 528 382 1 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 16744E*08 52 7 0 3740E-03 3 366 412 4 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 24 146E*08 53 8 0 2867E-03 4 825 453 3 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 34285E*08 54 9 0 1995E-03 7 868 514 2 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 49745E*0S 55 10 0 1122E-03 16 964 623 6 0 0 0 0 0 0 0 0 19 022 71 560 9.417 0 78489E*08 56 1 0 1122E-03 78 905 2870 1 7 740 1 581 18 109 0 533 1 243 70 794 0 7B622E+08 57 2 0 1995E-03 39 504 2567 5 8 543 0 825 18 453 0 284 0 742 71 153 -0 58807E+08 58 3 O 2867E-03 25 447 2383 0 8 914 0 476 18 606 0 174 0 512 71 317 -0 13782E»09 59 4 0 3740E-03 18 398 2250 0 9 113 0 289 18 691 0 112 0 388 71 406 -0 19207E*09 60 5 0 4613E-03 14 226 2147 5 9 240 0 169 18 747 0 072 0 308 71 464 -0 23271E+09 61 6 0 5485E-03 1 1 453 2056 1 9 240 o 169 18 747 0 072 0 308 71 464 -0 26476E+09 62 7 0 635SE-03 9 519 1980 6 9 240 0 169 18 747 0 072 0 308 71 464 -0 29099E+09 63 8 0 7231E-03 8 100 1916 7 9 240 0 169 18 747 0 072 0 308 71 464 -0 31306E*09 64 9 0 8103E-03 7 019 1861 4 9 240 0 169 18 747 0 072 0 308 7 1 464 -0 33203E+09 65 10 0 6976E-03 6 171 1812 8 9 240 0 169 18 747 0 072 0 308 71 464 -0 34858E+09 66 I.ME P(BAR> 15.234 P0WER(4 STROKE) (KW) 24 946 THERMAL EFFICIENCY 43.21 b) g a s o l i n e ( i s o o c t a n e i n g a s e o u s f o r m ) f u e l l e d e n g i n e OTTO CYCLE ANALYSIS PROGRAM INPUT DATA 12 13 23 24 25 29 30 31 32 35 36 37 38 CVL DIA (M) O.tOO STROKE (M) 0.100 COMP RATIO 8 00 AIR FUEL RATIO 15.27 CARBON ATOMS IN FUEL HYDROGEN ATOMS IN FUEL HEAT OF REACTION (J/KG) TRAPPED PRESS (N/M««2) TRAPPED TEMP (K) 298.0 REF PRESS (N/M"2) 101325.000 REF TEMP (K) 298.0 ENGINE SPEED (RPS) 41.7 AIR FUEL RATIO STOICHIOMETRIC 15.121 FUEL AIR EQUIVALENCE 0.990 .00 18 .00 -43500000.0 101325.000 FOLLOWING SPECIES IN PERCENT VOLUME NERGY (ABSOLUTE) IN J PER KGMOL FUEL 44 STEP V0L(M->3) PRESS(BAR) TEMP(K) C02 C 0 H20 H2 02 N2 CNHM ENERGY 45 46 1 0. 8976E-03 1 .013 298 .0 0 .0 0. 0 0. 0 0 .0 20 656 77 . 708 1 .636 -0 .10409E+09 47 2 0. 8103E-03 1 . 163 308 9 0 .0 0. 0 0. 0 0 .0 20 .656 77 .708 1 .636 -0 B6278E*08 48 3 0. 7231E-03 1 .357 321 .4 0 .0 0 0 0 0 0 .0 20 .656 77 . 708 1 .636 -0 69971E*08 49 4 0. 6358E-03 1 .613 336 .0 0 .0 0. 0 0. 0 0 .0 20 .656 77 . 70B 1 .636 -0 48407E'08 SO 5 0. 5485E-03 1 .967 353 .5 0 .0 0 0 0 0 0 .0 20 .656 77 . 708 1 .636 -0 22429E*08 51 6 0. 4613E-03 2 .480 374 .9 0 .0 0. 0 0 0 0 0 20 656 77 .708 1 .636 0 ,98066E*07 52 7 0. 3740E-03 3 .282 402 2 0 .0 0 0 0 0 0 .0 20 .656 77 .708 1 .636 0 5I487E»08 53 8 0. 2867E-03 4 .674 439 . 1 0 .0 0 0 0 0 0 .0 20 656 77 . 708 1 .636 0 10877E-09 54 9 0. 1995E-03 7 .546 493 .2 0 0 0 0 0. 0 0 0 20 656 77 . 708 1 .636 0. 19454E+09 55 10 0. 1122E-03 16 .023 589 .0 0 .0 0 o • 0 0 0 .0 20 .686 77 . 708 1 .636 0. 35200E*09 56 1 0. 1122E-03 Bl .659 2810 8 10 .563 1. 697 13 477 0 .315 1 . . 198 72 .750 0. 35126E*09 57 2 0. 1995E-03 40 896 2515 . 1 11 .465 0. 856 13. 700 0 . 161 0. 702 73 . 1 15 -0. 46665E»09 58 3 0. 2867E-03 26 336 2333 .5 11 .869 0. 480 13. 802 0 091 0 .479 73 . 279 -0 93796E+09 59 4 O. 3740E-03 19 .066 2206 .8 12 . 105 0 262 13 898 0 015 0. 333 73 .387 -0. 12610E-M0 60 5 0. 4613E-03 14 .666 2093 .5 12 . 105 0 262 13 898 0 .015 0. 333 73 .387 -0. 15034E-M0 61 6 0. 5485E-03 11 .805 2004 .0 12 . 105 0 .262 13 898 0 015 0 .333 73 .387 -0. 16936E*10 G2 7 0. G358E-03 9 .810 1930 .2 12 . 105 0 .262 13 898 0 .015 0. 333 73 387 -0. 18493E+10 63 B 0. 7231E-03 8 . 346 1867 .6 12 . 105 0 .262 13. 898 0 .015 o. 333 73 387 -O. 19802E*lO 64 9 0 8103E-03 7 . 232 1813 .6 12 . 105 0 .262 13 898 0 .015 0 333 73 . 387 -0. 20927E+ 10 65 10 0. 8976E-03 6 .358 1766 . 2 12 . 105 0 262 13. 898 0 .015 0 333 73 . 387 -0. 21908E*10 66 I ME P(BAR) 15.984 POWER(4 STROKE) (KW) 26. 175 THERMAL EFFICIENCY 42 . 14 76 A p p e n d i x C. Flame Speed C a l c u l a t i o n s A model i s c o n s t r u c t e d f o r s i m u l a t i o n o f t h e f l a m e p r o p a g a t i o n . The a s s u m p t i o n s made i n t h e model a r e : - t h e c y l i n d e r m i x t u r e i s an i d e a l gas w i t h c o n s t a n t s p e c i f i c h e a t - b u r n t and u n b u r n t zone have t h e same gas p r o p e r t i e s - no h e a t l o s s e s t o t h e w a l l - c o m b u s t i o n s i m u l a t e d by h e a t t r a n s f e r t o t h e b u r n i n g f r a c t i o n . D u r i n g a t i m e A t , a s m a l l amount o f m i x t u r e i s b u r n t , a f t e r w h i c h t h e f l a m e expands t o o b t a i n a u n i f o r m c y l i n d e r p r e s s u r e . The d i f f e r e n t s t e p s u s e d i n t h e computer program a r e as f o l l o w s : RF 1 •! J L a) i n i t i a l s i t u a t i o n TA1,VA1,XMA1 t e m p e r a t u r e , v o l u m e , m a s s of b u r n t VB1 PI zone VI PI XMAS TB1,VB1,XMB1 t e m p e r a t u r e , v o l u m e , m a s s of u n b u r n t zone P1,V1,XMAS c y l i n d e r p r e s s u r e , v o l u m e , m a s s RF r a d i u s of f l a m e f r o n t F A = t o t a l f u e l m a s s / t o t a l m i x t u r e mass 77 b b) mass burnt in time step t radius change Ar^ gives the volume fraction which burns VA2, volume of burnt zone, i s calculated mass burnt DM=P1 *(VA2-VA1)/R/TB1 amount of fuel burnt=DM*FA •c) constant pressure burning the mass fraction DM burns at pressure P1 i the burnt zone VA1 stays at pressure P1 the temperature of the newly burnt fraction is TCPB dq=dh or FA*HU=Cp*(TCPB-TB1) HU is the combustion value of the fuel V2 XMAS d) mixing of burnt gases XMA2=XMA1+DM XMB2=XMAS-XMA2 mixing takes place at constant pressure P1 temperature TAM=(DM*TCPB+XMA1*TA1)/XMA2 volume burnt zone VAM=XMA2*R*TAM/P1 volume unburnt zone VBM=V2-VAM 78 e) uniform pressure a d i a b a t i c compression of VAM a d i a b a t i c expansion of VBM volume change DV (negative number) volume of unburnt mixture at pressure PI i s VB1*XMB2/XMB1 same mixture at pressure P2 has a volume VBM-DV volume of burnt mixture at pressure P1 i s VAM same mixture at pressure P2 has a volume VAM+DV c o n s i d e r i n g i d e n t i c a l p r o p e r t i e s f o r both zones: (VBM-DV)/(VB1*XMB2/XMB1)=(VAM+DV)/VAM ^ f) f i n a l s i t u a t i o n VA2=VAM+DV VB2=V2-VA2 P2 = P1 *(VAM/VA2)**k 'TA2 and TB2 from i d e a l gas equation 1 REAL IMEP 8 1 2 READ (5.10) BORE,STROKE,CR.DL,RPM 82 3 READ (5.10) RAF.AFST.PI.TI.HU.CVA.CVB.R 8 3 4 READ (5.10) FRAC.PE.TE 8 4 5 READ (5.10) SPADV,DDEGR.RFI,ACCUR,FSP 8 5 6 10 FORMAT (BFI0.0> 8 6 7 C THIS PROGRAM CALCULATES THE OTTO CYCLE AND IT TAKES A LIMITED 87 B C BURNING SPEED INTO ACCOUNT; GAS PROPERTIES ARE CONSTANT BUT CV 8 8 9 C VALUES FOR BURNED MIXTURE (CVA) AND UNBURNED (CVB) ARE DIFFERENT. B9 10 C 9 0 11 DHUST-HU 9 1 12 DOEGRX-DDEGR 9 2 13 XKA"1.O+R/CVA 9 3 14 XKB"1.O+R/CVB 9 4 15 DO 100 I"9. 13 9 5 16 RAF-O. f l 9 6 17 HUST'DHUST 9 7 18 IF(AF5T.GT.16.0) HUST"RAF/(RAF+0.11)"OHUST 9 8 19 IF(I.EO.B) GO TO 100 9 9 20 RAFRES»RAF 1 0 0 21 IFIRAFRES.LE.1.0) RAFRE5-1.0 22 PE-62O0OO.0-300000.0'(RAFRES-t.O) 102 23 TE"1830.O-100O.0*(RAFRES-1.0) '03 24 DO 120 11-3.9 'O4 25 IF( I GE. 12.AMD.( II E0.4.0R. II E0.6)) GO TO 120 105 26 SPADV"5.0"II 1 0 6 27 WRITE (6.140) RAF.SPAOV 107 28 140 FORMAT(' '.'AIR/FUEL RATIO '.F3.1.' SPARK '.F4.1.' BTDC' ) 108 29 00 160 III"1. 1 '09 30 IP-1 1 1 0 31 RF-0.0 H I 32 WORKT-0.0 112 33 DF«0.0 113 34 DFT-0.0 114 35 DDEGR"ODEGRX 115 36 PMAX-0.0 I ' 6 37 TAMAX-0.0 117 38 TBMAX-0.0 118 39 VELUG-0.0 119 40 C 120 41 C INITIAL CONDITIONS IN CYLINDER TAKING RESIDUAL FRACTIONS INTO ACCOUNT 121 42 HU-HUST 122 43 IF(RAF.LT.I.O) HU"RAF"HUST 123 44 DEGR--180.0 124 45 CALL VOLUME (VOL. DEGR. BORE, STROKE .CR. DL. VOLA . VOLB. RF . IP) 125 46 VEE"VOL/CR"FRAC 126 47 TEE-TEM(PI/PE)*•((XKA-1 OI/XKA)) 127 48 XMAS1-PI*VEE/R/TEE 128 49 XMAS2-PIMVOL-VEE )/R/TI 129 50 XMAS»XMAS1*XMAS2 130 51 T1"(XMAS1"CVA"TEE*XMAS2"CVB"TI)/XMA5/CVB 131 52 PI-PI 132 53 V1-V0L 133 54 C 134 55 C AIR/FUEL CONDITIONS 135 56 FT"XMAS2/ ( 1 .O+RAF * AF ST) 136 57 FA«FT/XMAS 137 58 C 1S8 59 PW"P1" 1 .OE-05 139 60 VW»V1"1.0E06 140 61 WRITE (6.60) DEGR.PW.T1.VW 141 62 60 FORMAT(' '.F6. 1 .2X.F6.2.2X.F6.1.2X.6X.2X.F6 . 1 ) 142 63 C 143 64 C ADIABATIC COMPRESSION STROKE 144 65 SPADV"-SPADV 145 66 CALL VOLUME(V2,SPADV.BORE,STROKE.CR,DL.VOLA,VOLB.RF,IP) 146 67 P2»P1MV1/V2)*"XK8 147 68 T2"P2*V2/XMAS/R 148 69 W0RKT"XMAS"CVB'(T2-T1 ) 149 70 P1"P2 150 71 V1-V2 151 72 TI»T2 152 73 U1-XMAS"CVB"T1 153 74 DEGR = SPADV 154 75 PW-P1•1.OE-05 155 76 VW-V1M.0E06 156 77 WRITE (6.60) DEGR.PW.T1.VW 157 78 C 158 79 C PROGRESSIVE BURNING PTRIOD 159 ao rrriip ••/>. > 160 IP-0 TAI"T1 VA1"0.0 TB1-T1 VB1-V1 XMA1"0.0 XMB1=XMAS RF.RFI DEGR"SPADV GO TO 20 C 40 UL"FSP*1 OB7E07/I1.0E04/TA1*900.O/TB1)•"4.500*(P1/3342)••(-.09B7) IF(VA1.GE.(0.95*V1)) DDEGR"0.2 IF(VA1.GE.(0.97*V1)) DDEGR-0.05 IF(VA1.GE.(0.99*V1)) DDEGR>0.025 DRF-UL*DDEGR/6.0/RPM RF.RF+DRF+VELUG'DDEGR 20 CONTINUE 0EGR"DEGR»0DEGR CALL VOLUME ( VOL .OEGR. BORE , STROKE . CR.DL . VOLA, VOLB, RF , IP ) IF(IP EO.1) GO TO SO VA2=V0LA VB2"V0LB V2.V0L DM"P1 MVA2-VA1 1/R/TB1 DF.DM-FA/FTMOO.O DF T-DFT+OF TCPB"(FA"HU*(CVB»R)"TB1)/(CVA*R) XMA2"XMA1+DM XKB2-XMAS-XMA2 IF(XM82.LE.O.OI GO TO 50 TAM.(OM"TCPB*XMAl"TA1)/XMA2 VAM'XMA2»R"TAM/P1 VBM-V2-VAM DV=(XMB1'VBM/XMB2/VB1 - 1.0)/(1.0/VAM+XM81/XMB2/VB1) VA2-VAM+DV VB2»V2-VA2 P2"P1•(VAM/VA2)* "XKA TA2"P2"VA2/R/XMA2 TB2"P2»VB2/R/XMB2 C CALCULATION OF FLAME FRONT RADIUS AFTER EXPANSION OF FLAME XRF-(VA2*1 0E09-3.0/2.0/3 . 14 159) • • < 1 ./3 .) 0EG«0EGR/18O.O"3.141593 DIST"STROKE"(1./(CR-1 )•.5"<1.-COS(OEG)l»STR0KE/4./DL"(SIN(DEG))•"2) IF(RF LE DIST) GO TO 30 XRF =RF XRF"SORT(1/6.0"(2.0"DIST"«2*6.0"VA2/1.0E-09/3.14159/DIST)) 30 DIST"(V2-VA2)"1.0E09/I3.14159*B0RE""2/4.0) VELUG"(VB2-VB1*XMB2/XMB1)«1.0E09/I3.14159'BORE""2/4 0)/0DEGR/2.O IF(VELUG.LE.0.0) VELUG-0.0 DREE"XRF-RF CD 1"CENTR-RF C02"BORE-CENTR-RF 0RFE2"2 0"ORFE/(1 0*C01/C02) CENTR"CENTR*DRFE2-0RFE RF"XRF CALL VOLUME(VOL.OEGR.BORE.STROKE.CR.DL.VOLA.VOLB,RF.IP) VA2"V0LA C U2"XMA2*CVA*TA2+XMB2"CVB*TB2 W0RKT"W0RKT*U2-U1-DM"FA"HU T A 1= T A2 P1"P2 XMA1-XMA2 VA1»VA2 TB 1 "TB2 XMB1"XMB2 V81"VB2 UI«U2 V1»V2 CO H" 3 C I—1 rt H-O t j H O <Q H P> 3 PW = P1 * 1.OE-05 VW=V1*1.0E06 VWA 1 = VA1 * 1.0E06 VWB1=VB1* 1.0E06 WRITE(6,71 ) DEGR.PW,VWA t.VWB1.RF.DRF.DRFE.DRFE2.CENTR FORMAT( ' ' ,FG. 1. 2X,F6.2.2X.FG. 1 ,2X,F6. 1 .2X.F6.2.4(2X.F6.3 > > IF(P1,GT.PMAX)PMAX=P1 IF! TA1 .GT . T AMAX t T AMAX = T A 1 161 IF(TB1.GT.TBMAX)TBMAX"T81 162 GO TO 40 163 C ENO OF COMBUSTION 164 50 CONTINUE 165 C 166 C CYLINDER CONDITIONS ARE NOW P1. V1 , U1. XMAS .CVA AND Tl IS ... 167 T1-U1/XMAS/CVA 168 WRITE (6.70) DEGR.PW.TA1.TBI.VW.RF.DF,OFT 169 70 FORMAT(' •,F6 1.2X.F6.2.2X.3IF6.1.2XI.F5.1.2(2X,F5.1)) 170 C 171 C EXPANSION STROKE AFTER END OF COMBUSTION 172 DEGR.180 0 173 CALL VOLUME(V2,DEGR.BORE,STROKE,CR,DL.VOLA,VOLB,RF,IP) 174 P2 = P1MV1/V2)**XKA 175 T2-P2'V2/XMAS/R 176 W0RKT-W0RKT*XMAS,CVA'(T2-T1 ) 177 U2"XMAS*CVA*T2 178 PW.P2 * 1-OE-05 179 VW-V2- 1 .0E06 180 WRITE (6.60) DEGR.PW.T2.VW 181 PE-P2 182 TE-T2 183 SPADV.-SPADV 184 160 CONTINUE 185 C 186 WORKT'-WORKT 187 EFF"WORKT/(FT«HUST)'100.0 188 IMEP-WORKT'1 0£O4/(STR0KE'3.14159'BORE••2/4 .0) 189 POWER-WORKT *RPM/120.0 190 WRITE (6.80) EFF.IMEP.POWER 191 80 FORMAT(' '.F6.3.5X.F6.2.F9.2) 192 PW.PMAX*1.OE-05' 193 WRITE (6.90) PW.TAMAX.TBMAX 194 90 FORMAT (' •.F6.2.5X.F7.2.5X.F7.2/) 195 120 CONTINUE 196 100 CONTINUE 197 STOP 198 END 199 SUBROUTINE VOLUME(VOL.DEGR.BORE.STROKE.CR.DL.VOLA.VOLB,RF.IP) 200 DEG-DEGR/180.0'3.141593 201 DIST-STROKE'(1./(CR- 1 . )*.5'(1.-COS(DEG))+STROKE/4./DL*(SIN(DEG))**2) 202 V0L"DIST>3. 14159 ,B0RE"2/4 .0* 1 OE-09 203 IF(IP.EO. 1) RETURN 204 VOLA=2.0/3.0*3.14159*RF**3*1.OE-09 205 1F(RF LE.DIST) GO TO 121 206 H=DIST 207 A»S0RT(RF"2-H««2) 208 B-RF 209 VOL A = 3. 14159/6.0*H*(3.0*A«"2+3.0'B"2+H**2)*1.0E-09 210 121 CONTINUE 211 VOLB'VOL-VOLA 212 1FI0EGR.GE 180.0) IP-1 213 1F(VOLA.GE.VOL.AND.RF.LE.(BORE/2.0)) IP»1 2 14 IF(RF.LE.DIST(RETURN 215 H-DIST 216 A«SORT(RF'*2-H»»2) 217 B'RF 218 VOLA-3. 14159/6.0*H«(3.O'A"2*3.O ,B"2»H"2)*1 .OE-09 219 IF(VOLA.GE.VOL) IP-1 220 VOLB-VOL-VOLA 221 RETURN 222 END OO o 9 10 15 16 17 18 19 20 23 24 25 26 29 30 31 32 41 42 50 51 52 53 54 55 56 57 58 59 60 64 65 69 70 77 78 79 80 LOGICAL •1 FUEL(20) PLUG(20) INTEGER MESS 1(4) / OEGR' ,'EES:', / . 8 MESS2I4) / P.O. • . ' F , ; ' / . 8 MESS3I4) / PRES' .'SURE' ' (BA' R); /. 8 MESS414) / M. E . ' .'P. ( ' •BAR)' / . 8 TEXT 1 (4 ) / FLAM'.'E AR' RIVA' •i AT / . a TEXT214) / PROB' .'El D', 'EGRE' 'ES / . 8 TEXT3MI / AFTE ' .R IG'. NITI' •ON /. 8 TEXT4I4) / PROB' . E2 D' , 'EGRE' 'ES /. 8 TEXT5I4) / PROB' .'E3 0'. EGRE' 'ES / . 8 TEXT6I4) / MOME ' .NT 0',  F PE' AK '/. 8 TEXT7I4) / PRES' ,'SURE ' . .DEG' REES /, 8 TEXT8I4I / AFTE ' .R TD' . C / . 8 TEXT9I4) / PEAK' .' PRE ' . 'SSUR' E / . a TEXT10(4)/ (BAR' .') ' ' ' /. 8 TEXT1K4)/ . ' ' , / . 8 TEXT12I4)/ M. E . ' .'P. F' . OR ' / . 8 TEXT13I4)/ INTA' . KE/E' . XHAU' ST /. 8 TEXT14(4)/ STRO' .'KE '. /. 8 TEXT15I4)/ POWE ' .R ST' . ROKE' / INTEGER TEXT16I4)/ CORR' .'ELAT'. ' ION • TEST / . 8 TEXT17(4)/ ION ' ,'PROB' . 'El' / . 8 TEXT1BI41/ ION ' .'PROB' . •E 2 ' /. 8 TEXT 19(4)/ ION ' .PROB' . E 3 ' / . 8 TEXT20(4)/ FLAM' .'E SP' . EED ' ' 182 / . 8 TEXT2114)/ FLAM' •E SP' . EED ' '283 /. 8 MESS5(4) / OEGR' . EES '. 'PROB' 'E1; / . 8 MESS6(4) / DEGR' .'EES ' . PROB' E2; / . 8 MESS7(4) / DEGR' . EES 'PROB.' 'E3; / COMMON /PLCOM/XMINA, DXA . XMI NO ,0X0, FUEL . RPM, TROT , RAF , SPADV, PLUG DIMENSION VX(5).VV(5).TRACK1(SOO).TRACK2(50O).TRACK3(5OO), 6TRACK4(500).TRACK5(500).TRACK6(500),TRACK7( 500).CLASS 1 ( 2, 50) . 6CLASS2(2.50).CLASS3(2.S0).CLASS4(2.50).CLASS5(2.S0).CLASS6(2.50), 6CLASS7(2.50).ARRAVX(50).ARRAVV(50). 6FLAME1(50O).FLAME2(50O).CLASS8(2.5O).CLASS9(2.5O). 60UANT1(7).0UANT2(7 ).QUANT3(7),OUANT4)7).QUANTS(7).0UANT6!7), 60UANT7(7).0UANT8(7).0UANT9(7) C C INPUT OF ENGINE PARAMETERS C READ (5.10) FUEL.PLUG.RPM,TROT,SPADV,RAF 10 FORMAT (40A1.4F10.0) READ 15.11) Kl.K2.K3.K4.K5.K6.K7 11 F0RMAT(7I2) CALL DATIN(I 1.TRACK I) CALL DATINII2.TRACK2) CALL DATINU3. TRACKS) CALL DATINU4.TRACK4) CALL DATIN(I5,TRACKS) CALL DATINU6.TRACK6) CALL DATINfI7.TRACK7) C C OUTPUT OF ENGINE PARAMETERS C WRITE (6.40) FUEL,RPM,TROT,RAF,SPADV,PLUG 40 FORMAT! ' 1 '/' 8'FUEL - '.T21.20A1/-0'.'ENGINE SPEED • '.T21.F6.1.' RPM'/'O'. S'AIR FLOW •',T21.F6.1.' % OF MAXIMUM'/'0'.'REL. AIR/FUEL RATIO •' 8.T21.F6.I/'O'. SPARK ADVANCE •'.T21.F6.1.' DEGR BTDC'/'O'. S'IGNITION SOURCE •'.T21.20A1/////) 1-1 WRITE (6.50) I 50 FORMAT(' ',T10.'MOMENT OF FLAME ARRIVAL AT ION PROBE '.11, 8' MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION'/) WRITE (6.60) 11. ( TRACKKLI .L-l. I 1 ) 60 FORMAT(' '.' NUMBER OF DATA POINTS • '.I3//25(' '.20F6.2)) 1-2 WRITE (6 ,40) FUEL . RPM. TROT, RAF . SPADV. PLUG WRITE (6.50) I WRITE (6.60) I2.(TRACK2(L),L-1.I2) 1*3 WRITE (6.40)FUEL.RPM.TROT.RAF.SPADV.PLUG WRITE (6.50) I WRITE (6.60) 13.(TRACKS(L),L*1,I3) WRITE (6.40)FUEL.RPM.TROT.RAF,SPADV.PLUG WRITE (6.70) 70 FORMAT(' '.T10,'MOMENT OF MAXIMUM PEAK PRE5SURE. 8,'DEGREES CRANKSHAFT AFTER TDC'/) WRITE 16.60) 14 . ( TRACK4I L t'.L-1 . 14 ) WPI Tr < s . io >F ur i . . PCM . runr. PUF . <;PADV . P L U O MEASURED IN 85 86 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 WRITE (6.80) 80 FORMAT(' '.T10.'MAXIMUM PEAK PRESSURE. MEASURED IN BAR'/) WRITE (6.60) 15,(TRACKS(L),L-1.15) WRITE (6.40IFUEL.RPM,TROT.RAF,SPADV,PLUG WRITE (6.90) 90 FORMAT!' '.TIO.'WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED '. 8' IN BAR (MEP)'/) WRITE (6.60) I6.(TRACK6(L).L-1,I6) WRITE (6,4O)FUEL,RPM.TR0T.RAF,SPADV,PLUG WRITE (6.95) 95 FORMAT!' '.TIO.'WORK DONE DURING COMPRESS ION/EXPANSION STROKE.'. 6'MEASURED IN BAR (MEP)'/) WRITE (6.60) I7.(TRACK7(L).L-1,I7) C C CALCULATION OF STATISTICAL PARAMETERS C C NCL-NUMBER OF CLASSES C CLA'LOWER LIMIT OF LOWEST CLASS C CLW-CLASS WIDTH C CALL STAT(TRACK 1,I 1,CLA1,CLW1.NCL1.CLASS 1.AVER 1.SPRD1.XMIN1,XMAX1. 8XM0D1.OUANT1.TOP I.TOPSP1) CALL STATITRACK2.12.CLA2.CLW2.NCL2.CLASS2.AVER2.SPRD2,XMIN2.XM1X2, 8XM0D2.0UANT2.T0P2,T0PSP2) CALL STAT!TRACKS.13,CLA3.CLW3.NCL3.CLASS3.AVER3.SPRD3,XMIN3.XMAX3, 8XMOD3,0UANT3.TOPS.T0PSP3) CALL STAT ( TRACK4 . 14 . CLA4 , CLW4 , NCL4 , CLASS4 , AVER4 , SPRD4, XMIN4, XMAX4 , &XM0D4,OUANT4,T0P4.T0PSP4) CALL STATITRACKS.15.CLA5.CLW5,NCL5.CLASS5,AVERS,SPRD5,XMIN5.XMAX5, 8XM0D5.OUANT5,T0P5.T0PSP5 ) CALL STATITRACK6.16.CLA6.CLW6.NCL6.CLAS5G.AVER6.5PR06.XMIN6.XMAX6, 8XM0D6. 0UANT6, T0P6. T0PSP6 ) CALL STAT ( TRACK7,17,CLA7.CLW7.NCL7,CLASS7,AVER7.SPRD7.XMIN7,XMAX7, 8XM007 . OUANT7 . T0P7 , T0PSP7 ) IF(K1.E0.0.0R.K2 EO.O) GO TO 102 DO 101 L-1.I1 101 FLAME 1 ( L )-TRACK2( D-TRACKKL ) CALL STATIFLAME 1.11.CLA8.CLW8,NCL8,CLASS8,AVERB,SPRD8.XMIN8.XMAX8. 8XM008. OUANT8 . TOPS . T0PSP8 ) 102 IFIK2.EO.O.OR.K3.EO.O) GO TO 104 00 103 L"1 . 12 103 FLAME21L)"TRACKS!L)-TRACK2(L ) CALL STAT!FLAME2,12.CLA9.CLW9.NCL9.CLASS9.AVER9.SPRD9.XMIN9.XMAX9, 8XM0D9.0UANT9.T0P9.T0PSP9) 104 CONTINUE C C OUTPUT OF STATISTICAL RESULTS WRITE (7.200) FUEL.RPM.TROT.RAF.SPADV.PLUG 200 FORMAT! 8'1'.T10.20A1/' '.T10. ENGINE SPEED'.T36.F6.1,' RPM'/ 8' '.TIO.'AIR FLOW'.T36.F5.1.' % OF MAXIMUM'/ 8' '.T10.'RELATIVE AIR/FUEL RATIO'.T36.F3.1/ 8' '.T10.'SPARK ADVANCE'.TS6.F4.1,• DEGR 8TDC'/ 8' '.T10,'SPARK PLUG: '.2011//) 1-1 WRITE (7.50) I WRITE (7.201) AVER1.SPR01.XMIN1.XMAX1.XMOD1.OUANT1,TOP 1.TOPSP1 201 FORMATC '.TIB. SAMPLE AVERAGE'.T43.F7.3/' '.T18, 8'STANDARD DEVIATION'.T43.F7.3/' '.T18.'SAMPLE MINIMUM'. 8T43.F7.3/' '.T18.'SAMPLE MAXIMUM'.T43.F7.3/' '.T18.'MODE VALUE'. 8T43.F7.3/' '.T18.'OUANTILES -S 3 4 5 6 7 *S'.T44.3(F6.3.1X).'<'. 8F7.3.'> '.31F6.3.1X)/' '.TIS.'MODE FROM NORMAL FIT'.T43.F7.3/' '. 8T18.'STANDARD DEV. NORMAL FIT'.T43.F7.S//) 1-2 WRITE (7.50) I WRITE (7.201) AVER2 . SPRD2 . XMIN2, XMAX2 , XM0D2 .OUANT 2 , T0P2 , T0PSP2 1-3 WRITE (7.50) I WRITE !7.201) AVER3.SPRD3,XMIN3.XMAX3,XM0D3.0UANT3.TOPS.T0PSP3 WRITE (7.70) WRITE (7.201) AVER4.SPR04,XMIN4.XMAX4.XM0D4,0UANT4,T0P4,T0PSP4 WRITE (7.81) Bl FORMAT!'1'/) WRITE (7.80) WRITE (7.201) AVER5,SPRD5,XMIN5.XMAX5,XMaD5.0UANT5.T0P5.T0PSP5 WRITE 17.90) WRITE (7.201) AVER6.SPRD6.XMIN6,XMAX6,XM0D6.0UANT6.T0P6,T0PSP6 WRITE (7,95) WRITE (7.201) AVER7,SPR07.XMIN7.XMAX7.XMOD7.OUANT7.T0P7,T0PSP7 iriKI.FQ O OR K? EO 01 no TO 98 161 162 WRITE (7,96) FORMAT( ' '.T10, 'FLAME TRAVEL BETWEEN PROBE 1 » PROBE? IN '. 241 CALL PBOX (MLSS4.MESS2.TEXT 12,TEXT 13.TEXT 14.IA.10) 96 242 CALL LINE (ARRAYX,ARRAYY.50.1) 163 A'DEGREES CRANKSHAFT'/) 243 C 164 WRITE (7.201) AVER8.SPRD8.XMIN8.XMAX8.XM0D8.0UANT8,TOPS.T0PSP8 244 C HISTOGRAM FOR POWER(BAR) DURING COMPRESSION.EXPANSION 165 166 98 CONTINUE 245 READ 15.105IXMINA.DXA.XMINO.DXO IFIK2.EQ.O.0R.K3.EQ.O) GO TO 99 246 00 170 M-1.50 167 168 WRITE (7.97) 247 ARRAYX(M)-4.0+(CLASS7(1,M)-XMINA)/DXA 97 FORMAT! ' '.T10.'FLAME TRAVEL BETWEEN PROBE2 & PR0BE3 IN '. 248 170 ARRAYYIMI-4.0*(CLASS7(2,M)/I7/CLW7-(XMAX7-XMIN7)-XMINO)/0X0 169 5'DEGREES CRANKSHAFT'/) 249 IA-1 170 WRITE (7.2011 AVER9,SPRD9,XMIN9,XM1X9,XM009.0UANT9,T0P9. T0PSP9 250 10-1 171 99 CONTINUE 251 CALL PLOT (21.6.0.0.-3) 172 173 r 252 CALL PBOX <MESS4.MESS2.TEXT12.TEXT1S.TEXTt1.il.10) C PLOTTING RESULTS 253 CALL LINE (ARRAYX,ARRAYY.SO.1) 174 C 254 C 175 CALL PLCTRLI'METR'.1) 255 C CROSSPLOT. PROBE 1 ft PR0BE2 176 CALL PLCTRLC SCALE'. 1 .0) 256 READ (5.105) XMINA.DXA.XMINO.DXO 177 c 257 IF(K1.EO.O.OR.K2.EO.O) GO TO 300 178 C ION PROBE 1 HISTOGRAM 258 IA--1 179 READ (5.105)XMINA.DXA,XMIN0.0X0 259 I0-- 1 180 181 105 F0RMAT(4F10.0) 260 CALL PLOT (21.6.0.0.-3) DO 110 M- 1 , SO 261 CALL PBOX (MESS6.MESS5.TEXT16.TEXT17.TEXT18.IA.10) 182 ARRAVX(M)-4.0MCLASS1< 1 ,M)-XMINA )/OXA 262 CALL ORDER!TRACK2.TRACK 1,11,XMIN2.XMAX2,XMIN1,XMAX1,XMINA,DXA, 183 110 lRRAVY!M)-4.0*1 CLASS 1(2.M)/I1/CLW1•(XMAX1-XMIN1)-XMINO)/DXO 263 axMINO.DXO) 184 IA«-1 264 300 CONTINUE 185 10-1 265 C 186 CALL PBOX (MESS1.MESS2.TEXT1.TEXT2.TEXTS.IA.10) 266 C CROSSPLOT PR0BE2 8 PR0BE3 187 CALL LINE (ARRAYX.ARRAYY,50,1) 267 READ (5.105) XMINA.DXA.XMINO.DXO 188 C 268 IFCK2.EO.O.OR.K3.EO.O) GO TO 301 189 C ION PROBE 2 HISTOGRAM 269 IA--1 190 READ 15.105)XMINA.DXA,XMINO,0X0 270 I0--1 191 DO 120 M-1 .50 271 CALL PLOT (21.6.0.0.-3) 192 ARRAYX(M)-4 0*(CLASS2(1.M)-XMINA)/0XA 272 CALL PBOX (MESS6.MESS7.TEXT16.TEXT18.TEXT19.IA,10) 193 120 ARRAVY(M)>4.0*(CLASS2(2,M)/I2/CLW2«(XMAX2-XMIN2)-XMINO)/OXO 273 CALL ORDER!TRACK2.TRACKS.12,XMIN2.XMAX2.XMIN3.XMAXS.XMINA,0X1, 194 I1--1 274 &XMINO.DXO) 195 10-1 275 301 CONTINUE 196 CALL PLOT (21.6.0 0.-3) 276 C 197 CALL PBOX 1MESS1.MESS2.TEXT1.TEXT4.TEXT3.IA.I0) 277 C CROSSPLOT PROBE 1 9 PEAK PRESSURE 198 CALL LINE (ARRAVX.ARRAVV.50,1) 278 READ (5.105) XMINA.DXA.XMINO.DXO 199 C 279 IFIK1.EO.O.OR.K5.EO.O) GO TO 302 200 C ION PROBE 3 HISTOGRAM 280 IA--1 201 READ (5.105)XMINA,DXA.XMINO.0X0 281 I0--1 202 DO 130 M-1.50 282 CALL PLOT (21.6.0.0.-3) 203 1RR1YX(MI-4.0*<CL1SS3(1,M)-XMINA)/OXA 283 CALL PBOX (MESS3.MESS1.TEXT 16.TEXT9.TEXT 17.IA.10) 204 130 ARRAYY(M)-4.CH(CLASS3(2.M)/I3/CLW3*<XMAXS-XMIN3>-XMIN0)/DX0 284 CALL ORDER! TRACKS . TRACK 1.1 1 , XMIN5. XMAX5. XMIN1. XMAX 1. XMINA,DXA. 205 IA--1 285 &XMINO.DXO) ° 206 10-1 286 302 CONTINUE 207 CALL PLOT (21.6.0.0.-3) 287 C 208 CALL PBOX (MESS1.MESS2.TEXT1,TEXTS.TEXTS, IA,10) 288 C CROSSPLOT PR0BE2 8 PEAK PRESSURE 209 CALL LINE (ARRAYX,ARRAYY.50.1) 289 READ 15.105) XMINA.DXA.XMINO,DXO '210 c 290 IFIK2.EO.O.OR.K5.EO.O) GO TO 303 211 C MOMENT OF PEAK PRESSURE HISTOGRAM 291 IA-- 1 212 READ (5.105)XMINA,DXA.XMINO.DXO 292 I0--1 213 DO 140 M-1.50 293 CALL PLOT (21.6.0.0.-3) 214 ARRAYX(M)-4.0+(CLASS4(1,M)-XMINA)/DXA 294 CALL PBOX (MESS3.MESS1.TEXT 16,TEXT9.TEXT 18.IA.10) 215 140 ARRAYY(M)-4.O+(CLASS4<2,M)/I4/CLW4-(XMAX4-XMIN4)-XMIN0)/DX0 295 CALL ORDER!TRACKS.TRACK2,12,XMIN5,XMAXS,XMIN2,XMAX2,XMINA,DXA, 216 IA--1 296 &XMINO.DXO) 217 10-1 297 303 CONTINUE 218 CALL PLOT (21.6,O.O.-3) 298 C 219 CALL PBOX (MESS1.MESS2.TEXT6.TEXT7,TEXT8,IA.id) 299 C CROSSPLOT PROBES 8 PEAK PRESSURE 220 CALL LINE (ARRAYX.ARRAYY.50.1) 30O 225 CONTINUE 22 1 C 301 READ (5.105) XMINA.DXA,XMINO,0X0 222 C HISTOGRAM OF PEAK PRESSURE VALUES 302 IFIKS.E0.0.0R.K5 EO.O) GO TO 304 223 READ (5.105)XMINA,DXA.XMINO.DXO 303 IA*- 1 224 00 150 M- 1 ,50 304 I0--1 225 ARRAYX(M)*4.0*(CLASS5( 1 .M)-XMINA)/0XA 305 CALL PLOT (216.0.0.-3) 226 150 1RRAYY(M)-4.0*(CLASS5(2,M)/I5/CLW5-(XMAX5-XMIN5)-XMIN0>/DX0 306 CALL PBOX 1MESS3.MESS1.TEXT16.TEXTS,TEXT19.IA.10) 227 IA- 1 307 CALL ORDER( TRACKS . TRACKS. 13.XMIN5, XMAXS. XMIN3. XMAXS, XMINA,DXA, 228 10-1 308 8XMIN0,DX0) 229 CALL PLOT (21.6.0.0.-3) 309 304 CONTINUE 230 CALL PBOX (MESS3.MESS2.TEXT9.TEXT10.TEXT11.IA.10) 310 C 231 CALL LINE (ARRAYX.ARRAYY.50.1) 311 C CROSSPLOT MOMENT OF PEAK PRESSURE 8 PEAK PRESSURE 232 C 312 READ (5,105) XMINA.DXA.XMINO.DXO 233 C HISTOGRAM FOR POWER!MEP) DURING INTAKE/EXHAUST 313 IF(K4.EO.O.0R.K5.EO.O) GO TO 305 234 READ(5.105IXMINA.DXA.XMINO,DXO 314 IA-- 1 235 DO 160 M-1.SO 315 10-- 1 236 ARRAYX(M)*4.0*(C LASS6( I.M)-XM1NA)/OXA 316 CALL PLOT (2 1.6.0.0.-3) 237 160 ARRAYY(M.)-4.0* (CLASS6(2.M)/16/CLW6*(XMAX6-XMIN6)-XMINO)/0X0 317 CALL PBOX IMESS3.MESS1.TEXT 16.TEXT9.TEXT6.IA.10) 238 IA-2 318 CALL ORDER!TRACKS.TRACK4.14.XMIN5.XMAXS.XMIN4.XMAX4.XMINA,0X1. 239 10- 1 319 &XMIN0.DX0) 240 CALL PLOT ( 7 1 . 6 . n o.-3 1 320 305 CONTINUE 321 C 322 C HISTOGRAM FOR FLAME SPEED BETWEEN PROBE 182 323 REAO (5.105) XMINA,DXA,XMINO.0X0 324 IF(K1 EQ O.OR K2.E0.0) GO TO 306 325 DO 210 M- 1 .50 326 ARRAYXIM>-4.0*ICLA5S8( 1 .Ml-XMINA)/DXA 327 210 ARRAYY(M)-4.0*(CLASS8(2.MI/I1/CLW8MXMAXB-XMIN8)-XMIN0)/DX0 328 IA--1 329 10" 1 330 CALL PLOT 121.6.0 0.-3) 331 CALL PBOX (MESS 1.MESS2.TEXT20,TEXT 11,TEXT 11.1A, 10) 332 CALL LINE (ARRAYX.ARRAYY.50.1) 333 306 CONTINUE 334 C 335 C HISTOGRAM FOR FLAME SPEED BETWEEN PROBE 283 336 READ 15.1051 XMINA.DXA,XMIND.DXO 337 IFIK2 EO O.0R.K3.EQ.O) GO TO 307 338 00 220 M" 1 .50 339 ARRAYX!NI-4.0*(CLASS9( 1 ,M)-XMINAl/OXA 340 220 ARRAYY(MI-4.0*(CLASS9(2.M)/I2/CLW9"(XMAX9-XMIN9)-XMIN0)/DX0 341 IA--1 342 10-1 343 CALL PLOT 121.6.0.0.-3) 344 CALL PBOX <MESS 1.MESS2.TEXT21.TEXT 11.TEXT 11.IA. 10 ) 345 CALL LINE (ARRAYX,ARRAYY.50.1) 346 307 CONTINUE 347 C 348 C CROSSPLOT FLAME SPEED PROBE 182 AND PEAK PRESSURE 349 READ (5.105) XMINA.DXA.XMINO.0X0 350 IF(K1 EO 0.0R.K2. EO 0 OR K5 EO.O) GO TO 308 351 IA--1 352 I0--1 353 CALL PLOT (21.6.0.0.-3) 354 CALL PBOX (MESS3.MESS 1.TEXT 16.TEXT9.TEXT20.IA.10) 355 CALL ORDER(TRACKS.FLAME 1.11.XM1NS.XMAX5.XMIN8.XMAX8.XMINA.OXA. 356 8XMIN0.DX0) 357 308 CONTINUE 358 C 359 C CROSSPLOT FLAME SPEED PROBE 283 AND PEAK PRESSURE 360 READ (S.105) XMINA.OXA.XMINO.DXO 361 IF(K2.E0 O.OR.K3.EO.O.OR.K5.EQ.0) GO TO 309 362 IA--1 363 I0--1 364 CALL PLOT (21.6.0.0.-3) 365 CALL PBOX (MESS3.MESS 1.TEXT 16.TEXT9.TEXT21.IA.10) 366 CALL ORDER!TRACK5,FLAME2.12,XMIN5.XMAX5.XMIN9,XMAX9.XMINA,DXA, 367 8XMIN0.DX0) 368 309 CONTINUE 369 C 370 CALL PLOTND 371 STOP 372 END 373 SUBROUTINE OATIN!I.TRACK) 374 DIMENSION TRACK!500).VX(5).VY( 5) 375 READ (5.10) I.SCALE.SHI FT 376 10 FORMAT ( 13 . 2F 10.0) 377 READ (5.20) 11.XORG.YORG.XABS.YABS.XORD.YDRD.XA.YA.XB.YB 378 20 FORMATI14.511X.2F6.0)) 379 SLOPE"(YB-YA)/(XB-XA) 380 B-YA-XA'SLOPE 381 00 30 L"1.I 382 REAO (5.20) 11.(VX(M).VY(M),M" 1.5) 383 00 30 M"I.5 384 C-VY(M)*VX(M)/SLOPE 385 XINT-IC-Bl/(SL0PE*1 0/SLOPE) 386 YINT-SLOPE-XINT*B 387 DI ST«SORT((YINT-VY(M) ) •"2 + (XINT-VX!M))*"2)"0.0254"SCALE•1.25*SHI FT 388 IF(DIST.LE.0. 1 ) DIST-DIST*127.0 389 d"(L-1)-5+M 390 TRACK!JI-DIST 391 30 CONTINUE 392 I-I -5 393 RETURN 394 END 395 SUBROUTINE STAT(TRACK,I.CLA.CLW.NCL,CLASS.AVER,SPREAD.XMIN.XMAX, 396 8XM0D.OUANT.TOP.TOPSP) 397 DIMENSION CL(50).DAT!500».OUANT(7).TRACK!500).CLASS!2.50) 398 DO 5 L - 1 . 50 399 5 CLASSI2.L)=0.0 400 XMIN--TP*.C< 1 I 401 XMAX"TRACK(1) 402 SUM"0.0 403 SUMSO-0.0 404 C 405 C DETERMINE MIN.MAX.AVERAGE.SPREAD AND HISTOGRAM VALUES FOR DATA SET 406 C 407 00 8 L•1.I 408 TR"TRACK(L) 409 IF(TR.LT.XMIN) XMIN-TR 410 IF( TR.GT.XMAX ) XMAX"TR 411 8 CONTINUE 412 NCL-50 413 CLW"(XMAX-XMIN*0.000011/48.0 414 CLA-XMIN-CLW-O.000005 415 DO 10 L"1.I 416 TR-TRACK(L) 417 SUM"SUM+TR 41S SUMS0"SUMS0+TR""2 419 DO 30 M-1.NCL 420 IFITR.LT.(CLA.M"CLW)) GO TO 10 421 CLASS(2.M)-CLASS(2,M).1.0 422 30 CONTINUE 423 10 CONTINUE 424 AVER"SUM/I 425 SPREAD"SORT((SUMSO-I-AVER--2>/<1-1.0)) 426 C DETERMINE HISTOGRAM VALUES 427 DO 20 M"1.NCL* 428 CLASSI1,M)-CLA»CLW/2.0*(M-1.0>*CLW 429 NCLA"NCL-M 430 NCLB"NCL-M*1 431 IF(NCLA.EO.O) GO TO 20 432 CLASSI2.NCLB)"CLASS!2.NCLA)-CLASS!2.NCLB) 433 20 CONTINUE 434 CLASSI2.1)"I-CLASS(2.1) 435 DO 40 M-NCL.50 436 40 CLASS(1.M)"CLA*CLW/2.0*(M-1 0)«CLW 437 C TAKING MOVING AVERAGE OF HISTOGRAM 438 C WEIGHING FACTORS 1 4 10 4 1 439 CL(1)"(6.0*CLASS(2.1)*4.0*CLASS(2.2)*2 O'CLASSI2.3)* 440 aCLAS5(2.4))/20.0 441 CL(2)"(4 0*CLASS(2.1>*6 0*CLASS(2.2)*4.O'CLASSI2.3)• 442 82.0'CLASS(2.4>»CLAS5(2.5))/20.0 443 CL(3)"(2.0*CLASS(2.1)*4.O'CLASSI2.2)*6 0*CLASS(2.3>• 444 a4.0*CLASS(2.4)*2.0 ,CLASS(2.5)*CLASS(2.6))/20.0 445 00 90 L-4.47 446 LO-L-3 447 L1-L-2 448 L2-L-1 449' L3-L-M 450 L4"L»2 451 L5-L*3 452 CL(L)-(CLASS(2.LO)*2.0*CLASS(2.L1>*4.O'CLASSI2.L2)*6.0* 453 8CLASS(2.L)*4.0"CLASS(2.L3)*2.0"CLASS(2.L4)*CLASS(2.L5))/20.0 454 . 90 CONTINUE 455 CL(4B)-(CLASS(2.45)*2.0*CLASS(2.46)*4.0"CLASS(2.47)*6.0< 456 8CLASS(2.48)*4.0"CLASS(2.49I*2.0*CLASS(2.50)>/20.0 457 CL(49)-(CLASS(2.46>+2.0*CLASS(2.47)*4.0"CLASS(2.48>* 458 aGO*CLASS(2.49)*4.0'CLASS(2.50).)/20.0 459 CL(50)"(CLASS(2.47)*2.0*CLASS(2.48)*4.0"CLASS(2.49)* 460 . 86.0*CLASS(2.50)1/20.0 461 CLO 1-0.0 462 CL<50)"0.0 463 CLMAX"0.0 464 00 95 L"1.50 465 IF (CL ( L ) . LE . CLMAX ) GO TO 96 466 CLMAX'CL(L) 467 LMAX'L 468 96 CLASS(2.L)-CL(L) 469 95 CONTINUE 470 XMOD-CLASS!1.LMAX) 471 C FITTING A NORMAL DISTRIBUTION FOR CENTRAL DISTRIBUTED DATA POINTS 472 C THE AVERAGE IS AN INDICATION FOR THE MODE VALUE 473 DO 97 L-1,50 474 IL"L 475 IFICLfL).GE.(0.66"CLMAX)) GO TO 98 476 97 CONTINUE 477 98 XLO-CLASSI1.IL) 478 OD 10O L-1.50 479 LL-50-L+I 480 IL-LL CO 481 IFICLILL) GE . 10.66'CLMAX>) GO TO 101 5 6 ' 482 100 CONTINUE 5 5 2 483 101 XHI'CLASS! 1 .ID 5 6 3 484 TOP'0.0 5 6 4 485 TOPSP'0.0 5 6 5 486 XLNUM-0.0 5 6 6 487 DO 105 L-1.I 5 6 7 488 TR"TRACK(L) 5 6 8 489 IFITR.LT XLO.OR.TR.GT.XHI) GO TO 105 5 6 9 490 TOP-TOP'TR 5 7 0 491 T0PSP'T0PSP*TR"2 5 7 1 492 XLNUM-XLNUM*1.0 5 7 2 493 105 CONTINUE 5 7 3 494 TOP'TOP/XLNUM . 5 7 4 495 TOPSP-SORT!i TOPSP-XLNUM'T0P"2 )/(XLNUM-1 0))'2.516 5 7 5 496 C DETERMINE MODULUS AND QUANTILES 5 7 6 497 XLIM'XMIN-1.0 5 7 7 498 00 50 L-I.SOO 5 7 8 499 NUM'O 5 7 9 500 XM'XMAX 5 8 0 501 00 60 M. 1 .500 , 5 8 1 502 TR« TRACK IM) * 5 8 2 503 IFITR.LE.XLIM. OR. TR. GT. XM) GO TO 60 5 8 3 504 IFITR.EO.XM) GO TO 70 5 8 4 505 XM'TR 5 8 5 506 NUM.0 5 8 6 507 GO TO 60 5 8 7 508 70 NUM-NUM+1 588 509 60 CONTINUE 5 8 9 510 DO 80 NN"1.NUM 590 511 80 DAT!L+NN-1>*XM 591 512 XLIM'XM 592 513 50 CONTINUE 593 514 L"15.87/100.O'l 594 515 OUANT!1)'DAT|L> 595 516 L-30.0/100.O'l 596 517 OUANT(2).DAT(D 597 518 L-40.0/100.0*1 End of FI1 519 OUANTI3)>DAT(L) 520 L-I/2 521 QUANT!4).DAT!D 522 L-60.0/100 O'l 523 QUANT(5I"0AT(D 524 L-70.0/100 O'l 525 0UANr(6)'DAT(D 526 L-84.13/100.O'l 527 " OUANTI7)-DAT(L) 528 RETURN 529 END 530 SUBROUTINE ORDER ! TRACKA.TRACKO.I.AM1N,AMAX,OMIN.OMAX. 531 &XMINA.DXA.XMINO.0X0) 532 DIMENSION TRACKAI500).TRACKO!500),TRACKX!SOO).TRACKY(500) 533 00 10 L-1.30 534 VMIN'OMAX«0.001-L'IOMAX-OMIN*0.0021/30.0 535 YMAX"VMIN+!OMAX-OMIN+O.002)/30.0 536 J-0 537 DO 20 M"1.I 538 DUM'TRACKO(M) 539 IF! DUM. GT . YMAX . OR . DUM. LE . YMIN) GO TO 20 540 d"J*1 541 TRACKX!J)'TRACKA(M) 542 TRACKY!J).DUM 543 20 CONTINUE 544 XLIM'AMIN-0.001 545 DO 40 K-1.J 546 XMIN'AMAX»0.001 547 DO 30 M-1,J 548 DUM'TRACKX(M) 549 IFIDUM.GE.XMIN.OR OUM.LE.XLIM) GO TO 30 550 XMIN-OUM 551 • Y«TRACKY!M) 552 30 CONTINUE 553 X"4.0+!xMIN-XMINA)/OXA 554 Y'4.0+(Y-XM1NO)/DXO 555 CALL SYMBOL (X.V,0. 1.4.0.0.- 1 I 556 XLIM'XMIN 557 40 CONTINUE 558 10 CONTINUE 559 RETURN r.GO F Nn SUBROUTINE PBOX!ABS.ORD.TEXT 1.TEXT2.TEXT3.IA.10) LOGICAL*! FUELI20).PLUG(20) INTEGER ABS!4).ORD!4).TEXT 114).TEXT2I4).TEXTS!4) COMMON /PLCOM/XMINA.OXA.XMINO.0X0.FUEL.RPM.TROT.RAF.SPAOV.PLUG CALL AXCTRL!'SIDE'.11 CALL AXCTRL!'DIGITS'.10) CALL AXCTRL!'LABELS'.2) CALL AXCTRL!'XORIGIN',4.0) CALL AXCTRL!'YORIGIN'.4.0) CALL AXPL0K0R0.90 0. 14 .0. XMINO. 0X0) CALL AXCTRLI'SIDE'.-1) CALL AXCTRL!'DIGITS'.IA) CALL AXCTRL!'LABELS'.2) CALL AXPLOTIABS.O.O, 14 .0. XMINA . DXA ) CALL AXCTRL!'LABELS'.0) CALL AXCTRL!'DIGITS'.-2) CALL AXCTRL!'XORIGIN-.18.0) CALL AXPLOT! ' : '.90.0. 14.0.0.0.10.0) CALL AXCTRL!'XORIGIN',4.0) CALL AXCTRL!'YORIGIN'.18.0) CALL AXCTRL('SIDE'.1 ) CALL AXPLOT! '. ' .O O. 14 .0.O.O. 5.0) CALL PSYM!4.0.20 5.0.5.TEXT 1.0.0,16,8999) CALL PSYM14.0.19.75.0.5.TEXT2.0.0.16.8999) CALL PSYM(4.0,19.0.0.5,TEXT3.0.0.16.8999) CALL PSYM! 13.0, 20.8.0.2.FUEL.0.0. 20.8999) CALL NUMBER!13.0.20.4.0.2.RPM.0.0.- 1) CALL PSYM!14.5.20 4.0.2.'RPM•,O.0.3.8999) CALL NUMBER!13.0,20.0.0.2,TROT.0.0.- 1) CALL PSYM! 14.5.20.0.0.2, '7. AIR FLOW .0.0. 10.8999) CALL NUMBER ( 13 .0. 19 .6.0. 2.RAF .0.0. 1 ) CALL PSYMI14.5.19.6.0.2.'REL. AIR/FUEL RATIO',0.0.19.8999) CALL NUMBER!13.0.19.2,0.2,SPADV.0.0.- 1) CALL PSYM!14.5.19.2,0-2,'DEGREE5 BTDC SPARK TIMING',0.0.25.8999) CALL PSYM!13.0.18.8,0.2.PLUG.0.0.20.8999) 999 RETURN END CO 8 5 Appendix E. D i s t r i b u t i o n and C o r r e l a t i o n o f S i g n a l s FLAME ARRIVAL AT m PROBE 1 DEGREES ™ _ . r-r-r-, _ flEL, OTfRJEL RATIO H r J LR IGNITION *" DECREES BIX SWWK TDIDB STflHWRD PLUG 3S I Fig.29: d i s t r i b u t i o n probability density function of flame arrival at probe 1 measured in degrees crankshaft rotation after ignition. DEGREE! 5 5 r 65 75 FLAME ARRIVAL AT P R 0 B E 2 DEGREES AFTER IGNITION nnHRje 2soo RPM itte j mn FLOU 1.3 P.EL. ATRVFUEl RATIO 40 DEGREES STDC SPflRK TIffUC STflNMRD PLUG 3S Fig.30: I 2 d i s t r i b u t i o n probability density function of flame travel from ignition to probe 2 measured in degrees crankshaft rotation 86 MOMENT OF PEAK PRESSURE.DEGREES AFTER TDC 2SOO R B I JOO Jf ROT FUJU •.j REL. mi/njEL Rflno 40 DEGREES 8TDC SFJWt XMWG CTANQflRD PUJG 3 S Fig.32: T d i s t r i b u t i o n — PP probability density function of moment of peak pressure, measured in crankshaft degrees after top dead center 8 7 PEAK PRESSURE (BAR) nnwuc 2500 RPM ]«0 J PER FLOU 1.1 REL flDLTUEl RflTIO 40 DECREES 57DC SPARK TSUX STAJCRRD PUX 35 |- F i g . 3 3 : p ^ d i s t r i b u t i o n probability density function of th peak pressure during combustion, measured in bar i r 24.0 ~t 1 1 r 28.0 32.0 36.0 PRESSURE (BAR) 46.0 M.E.P. FOR INTAKE/EXHAUST STROKE J1EWRNE 2SQO RPM 100 7 FUR FUJI 1.1 REL. ATR/FUEL RATIO 40 DEGREES HIOC SPARK TTMINC STAMJPRD PLUG 35 F i g . 3 4 : i m e p I- d i s t r i b u t i o n i e probability density function of th work done during the intake and exhaust stroke (pumping losses); the work is indicated and measured in bar 0.4 0.44 0.48 ^ 0^ 5^  r{°j^ °-6 0 M 0 5 6 8 8 M.E.P. FOR POWER STROKE TSOO JWI 1.1 flEL ATR/FUEl RATIO 40 DEGREES SIDE SPARK CTtUC S7AMMRO PLUG 3S fx" _ l _ _J_ _1_ -1 1-— i 1 1 1 i 1 1 r = — i r — r 4.0 4.8 5.6 6.4 7.2 8.0 M . E . P . IBflLRJ — i r s.e Fig,35: imep^ d i s t r i b u t i o n probability density function of the work done during the compression and combustion/expansion stroke (power stroke); the work is Indicated and measured in bar 9.6 FLAME SPEED 1£2 JIITTHBJC 2500 HPfl ]«0 J Pfffl ROU J.l REL. .4EBJFUEL RATIO 40 DECREES BTOC SPARK TDUJG STANDARD PLUG 3S (_ F i g . 36: I 1 2 d i s t r i b u t i o n probability density function of flame travel from probe 1 to probe 2 measured in degrees crankshaft rotation DEGREEf 100 89 FLAME SPEED 2E3 JIETHANE 2500 M M J40 % FOR FLOU 1.1 PEL. ATR/FUEL RATIO 40 DEGREES S I X SPARK TJrUJC STANDARD PLUG 3S [_ F i g . 37 : d i s t r i b u t i o n probability density function of flame travel between probe 2 and probe 3 measured in degrees crankshaft rotation 'DEGREES5 CORRELATION TEST ION PROBE 1 ION PROBE 2 METHANE 2500 fiP/1 100 } R1F FLOU 1.1 PEL. AIR/FUEL RATIO 40 DEGREES S T X SPARK TIMING STANDARD PLUG 3S _l_ «1. i.» i r * ." . . " \ V, » .* . " _> • 11 » - • J"« «««>« • I I 1 1 1 1 1 1 1 1 1 1 -20 30 40 50 60 70 80 DEGREES PR0BE2 F i g . 3 8 : c o r r e l a t i o n between 1^ and the flame travel time from ignition to probe 1 and to probe 2 are shown in correlation with each other for 400 consecutive cycles 30 90 CORRELATION TEST ION PROBE 2 ION PROBE 3 CD to UJ LO LU o • 20 2S00 RPJ1 JOO •» FUR R£U J.J REL. ATJL/FUEL RATIO 40 DEGREES H7DC SPARK UrUJC S1SNURO PLUG 35 _l_ • " (j M • " »M • « M -M * M • jr - M W M , «.•*""*• M " • W K« «*X R M MM"" " » « « « « . * / - ' » _ " M • J»XM -,•»•• j r ' KB. M.KM _ / « K M M « " >f • M MM i i i i i i r 40 50 60 70 DEGREES PR0BE2 so F i g . 3 9 : c o r r e l a t i o n between I 2 and the flame travel time from ignition to probe 2 and to probe 3 are shown 1n correlation with each other for 400 consecutive engine cycles 30 CORRELATION TEST PEAK PRESSURE ION PROBE 1 flETHft* 2500 RPfl 140 T f f l FLOU 1.1 -REL ATR/FUEL RATIO 40 DEGREES B7DC SPARK TInlMG STANDARD PLUG 35 UJ UJ CK • CD UJ On. _1_ " " V / V ^ - . V : . ; . . . . " • * " . v ^ . ! : " 20 24 28 n r PRE?SURE flflR] i r 40 -1 r 44 46 F i g . 4 0 : c o r r e l a t i o n between I. and p 1 *p peak pressure and flame travel time from ignition to probe 1 are shown In correlation with each other for 400 consecutive engine cycles 91 CORRELATION TEST PEAK PRESSURE ION PROBE 2 fl ETHANE 2500 RPJ1 740 J RXR FLOW 1.1 PEL, AIR/FUEL RATIO 40 DEGREES 07DC SPARK TTJUNG STANJMRD PLUG 35 _1_ _L • « • * "*«_ N." «•"• « • •"• K K m K K " . » » , " " " • " . . ." » * " . *t _ K KK *""-«« " _ H " % K M - " . ire*« •" • • • * 20 -T -24 —I 1 1 1-26 32 PRESSURE 3HR) 40 -T -44 46 Fig.41: c o r r e l a t i o n between I„ and p 2 *p peak pressure and flame travel time from Ignition to probe 2 are shown in correlation with each other for 400 consecutive engine cycles CORRELATION TEST PEAK PRESSURE ION PROBE 3 71 ETHANE 2500 RPfl J40 I FUJI FLOU 1.1 PEL ATJLtfTJEL RATIO 40 DEGREES 57DC SPARK TTJT7JIC STANDARD PLUG 35 J_ _1_ _ l _ JL •"-« '.* • - ."„-..,. ja. .»" - « M " • -« «•> H ft * ft ft ft] ~1 I I I I I 1 1 1 1 1 1— 20 24 28 32 36 40 44 PRESSURE fBflRj Fig.42: c o r r e l a t i o n between I_ and p 3 *p peak pressure and flame travel time from ignition to probe 3 are shown in correlation with each other for 400 consecutive engine cycles 46 92 CORRELATION TEST PEAK PRESSURE FLAME SPEED 1e2 "ETHAie 2500 RPfl J80 * <ttR FLCU 1.1 REL ADVFUEL RATIO 40 DECREES B7DC SPARK TJrTJJC STANDARD PLUG 35 _l_ _1_ . • " . " ••" .4.-.•."•*.«-v" .> I I I I 1 1 1 1 1 I 1 1 20 24 28 32 36 40 44 PRESSURE IBRR) 46 Fig.43: c o r r e l a t i o n between I. _ and p 12 c v correlation between peak pressure and flame travel from probe 1 to probe 2 for 400 consecutive engine cycles CORRELATION TEST PEAK PRESSURE FLAME SPEED 2e3 HEWRJC 2S00 RPfl 100 x mx FLOU 1.1 REL ATA/FUEL RATIO 40 DEGREES J3TOC SPARK nrttMC STANDARD PLUG 35 J L J L J 1 I I l I i i • «» M H > M • K . . . • • w K 20 i r-24 1 r i r 28 32 36 40 PRESSURE (BAR) i 1 r 44 46 Fig.44; c o r r e l a t i o n between I 0-, and p 2 3 *p correlation between peak pressure and flame travel from probe 2 to probe 3 for 400 consecutive engine cycles 93 CORRELATION TEST PEAK PRESSURE MOMENT OF PEAK flETHftNE 2SOO RPfl J«0 J FOR FLOU J.J PEL. ADVFUEl RATIO 40 DEGREES 0 7 X SPARK TIflDC STANDARD PLUG 35 » <* «X «Y 20 24 26 PRESSURE HflRj 4 0 i 44 J_ 46 Fig.45: c o r r e l a t i o n between T and p f o r PP P methane a t X = l . l correlation test between the peak pressure and its arrival time for 400 consecutive engine cycles CORRELATION TEST PEAK PRESSURE MO.MENT OF PEAK —i—i—i—i—i i i KSOUNC 2S00 am •J-00 3 AM FLOTJ •o.s KL afvnxi nsno 30 xtfKti mot iPflB. nniM SMFOflRD FIX SS to"-LU LU or • \u Oo. _ l _ J_ 1 "v***. 26 '30 r— 34 PRESSURE llflRJ 46 —r-50 54 Fig.46: c o r r e l a t i o n between T and p f o r PP P g a s o l i n e a t X=0.9 test with gasoline: fast flame travel for rich mixture. slower flames have low peak pressure faster flames have higher peak pressures 94 CORRELATION TEST PEAK PRESSURE MOMENT OF PEAK tlETHAHE 2440 RPT1 100 t AIR FLOU 1.3 REL. AIR/FUEL RATIO 45 DEGREES BTOC SPARK TIMING STANDARD PLUG 3S co<2-LU LU OH • CD LU O n . _ L _1_ J_ J_ _1_ > « * . 10 18 2 6 PRESSURE (IflR) 50 5 8 6 6 Fig.47; c o r r e l a t i o n between T and p f o r PP P methane a t X =1.3 test with methane: slow flame travel at lean mixture, moment of peak pressure is Independent of flame speed except for very slow and fast flames CORRELATION TEST PEAK PRESSURE FLAME SPEED 1e2 (WSOONC 2500 am J-0O J fm FLOU D.9 ATJL-ruTL JBUIO so DCIMCCS -moe SPAK TJHMG SMNDBRD PUX 3S Fig.48: c o r r e l a t i o n between I, _ and p f o r 12 ^p g a s o l i n e a t X=0.9 for a fully developed flame, the flame propagation is independent of peak pressure, the sum of burning speed and expansion speed is constant but a fast flame shows a higher burning speed, as expected PRESSURE [IflR] METHANE ENGINE S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 3 0 SPARK P L U G : STANDARD P L U G 3 5 2 5 0 0 . 0 RPM t O O . O % OF MAXIMUM 0 DEGR BTOC MAXIMUM P E A K P R E S S U R E , MEASURED IN BAR MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 3 1 . 6 3 7 > 3 3 . 2 3 5 3 4 . 9 4 2 4 3 . 9 2 1 MOMENT OF F L A M E A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 34 159 STANDARD D E V I A T I O N S 401 S A M P L E MINIMUM 20 748 S A M P L E MAXIMUM B3 443 MODE V A L U E 30 544 O U A N T I L E S - 5 3 4 5 6 7 * S 27 944 MODE FROM NORMAL F I T 30 295 STANDARD D E V . NORMAL F I T 3 384 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 » S MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T 2 8 . 7 6 8 4 . 178 1 6 . 1 0 2 3 8 . 194 2 9 . 6 8 0 2 4 . 8 6 8 2 6 . 6 8 2 2 7 . 8 5 0 2 8 . 4 8 9 3 . 6 8 3 < 2 8 . 9 1 8 > 2 9 . 6 6 4 3 0 . 5 4 2 3 2 . 9 3 7 WORK DONE D U R I N G I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 50 186 S T A N D A R D D E V I A T I O N 12 881 S A M P L E MINIMUM 30 559 S A M P L E MAXIMUM 07 381 MODE V A L U E 42 563 O U A N T I L E S - S 3 4 5 6 7 * S 39 647 MODE FROM NORMAL F I T 43 346 5TANDAPD D E V . NORMAL F I T 5 6 0 0 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * S MODE FROM NORMAL F I T STANDARD O E V . NORMAL F I T 0 . 5 3 6 0 . 0 2 5 0 . 4 6 6 0 . 6 1 4 0 . 5 3 6 0 . 5 0 9 0 . 5 3 6 0 . 0 2 7 0 . 5 2 1 0 . 5 3 0 < 0 . 5 3 7 > 0 . 5 4 3 0 . 5 5 0 0 . 5 6 4 < 4 6 . 9 8 0 > 5 0 . 2 0 3 54 292 6 3 . 7 6 2 MOMENT OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 59 081 STANDARD D E V I A T I O N 11 239 S A M P L E MINIMUM 36 981 S A M P L E MAXIMUM 1 14 725 MODE V A L U E 50 748 O U A N T I L E S - S 3 4 5 6 7 * S 48 851 MODE FROM NORMAL F I T 55 067 STANDARO O E V . NORMAL F I T 11 6 5 3 S A M P L E A V E R A G E 7 9 6 8 STANDARD D E V I A T I O N 1 0 8 3 S A M P L E MINIMUM 0 108 S A M P L E MAXIMUM 9 108 MODE V A L U E 9 264 O U A N T I L E S - S 3 4 5 6 7 * S 7 811 MODE FROM NORMAL F I T 8 193 STANDARD D E V . NORMAL F I T 0 367 8 . 0 2 6 8 . 0 9 2 < 8 . 1 G S > 8 . 2 2 9 8 . 2 8 2 8 . 3 5 5 FLAME T R A V E L B E T W E E N PROBE 1 ft P R 0 8 E 2 IN O E G R E E S C R A N K S H A F T < 5 8 . 0 3 9 > 6 0 . 5 7 7 6 4 . 3 3 4 7 2 . 8 1 5 MOMENT OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC S A M P L E A V E R A G E 2 1 . 1 9 4 STANDARD D E V I A T I O N 6 . 9 9 6 S A M P L E MINIMUM 0 . 7 6 2 S A M P L E MAXIMUM 1 1 8 . 9 » 7 MODE V A L U E 2 1 . 6 8 6 O U A N T I L E S - S 3 4 5 6 7 +S 1 8 .1 8 4 1 9 . 8 2 4 2 0 . 4 4 4 < 2 1 . 1 9 5 > 2 1 . 5 0 7 2 2 . 2 5 6 2 3 . 3 3 4 MODE FROM NORMAL F I T STANDARD D E V . NORMAL S A M P L E A V E R A G E 16 0 2 6 S T A N D A R D D E V I A T I O N 14 209 S A M P L E MINIMUM - 2 1 0 1 7 S A M P L E MAXIMUM 54 4 1 3 MODE V A L U E 14 341 O U A N T I L E S - S 3 4 5 6 7 * S 6 308 MODE FROM NORMAL F I T 14 288 STANDARO O E V . NORMAL F I T 4 3 2 0 1 1 . 5 9 7 1 3 . 4 5 4 < 1 5 . 2 7 6 > 1 7 . 3 9 6 2 1 . 3 6 5 2 9 . 8 4 8 F L A M E T R A V E L B E T W E E N P R O B E 2 ft P R 0 B E 3 IN O E G R E E S C R A N K S H A F T 2 1 . 5 0 1 S A M P L E A V E R A G E 8 8 9 5 3 . 0 2 7 S T A N D A R D D E V I A T I O N 13 891 S A M P L E MINIMUM - 6 8 248 S A M P L E MAXIMUM 4 3 262 MODE V A L U E 11 9 0 0 O U A N T I L E S - S 3 4 5 8 7 * S - 3 918 MODE FROM NORMAL F I T 12 0 1 2 STANDARD D E V . NORMAL F I T 9 583 4 . 5 6 0 7 . 8 3 9 < 1 0 . 2 5 1 > 1 2 . 6 3 1 1 5 . 9 7 4 2 0 . 3 5 7 E x p e r i m e n t M l . A P35 METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 2525.0 RPM lOO.O % OF MAXIMUM 1 .0 MAXIMUM PEAK PRESSURE. MEASUREO IN BAR SPARK ADVANCE 35.0 DEGR BTDC SAMPLE AVERAGE 33 858 SPARK PLUG: STANDARD PLUG 35 STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM 4 . 23. 46 203 915 472 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE QUANTILES -S 3 4 5 6 7 *S 32. 29 .609 .518 31.422 32.516 < 33.635> 34 SAMPLE AVERAGE 3B .414 MODE FROM NORMAL FIT 33803STANDARD DEVIATION 9 312 STANDARD DEV. NORMAL FIT 5 .778 SAMPLE MINIMUM 17 .531 SAMPLE MAXIMUM 70 546 MODE VALUE 32 .442 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) QUANTILES -S 3 4 5 6 7 *S 29 .924 32.237 33 931 < 36.001> 39.278 43.677 49.720 MODE FROM NORMAL FIT 32 .413 SAMPLE AVERAGE 0 538 STANDARD DEV. NORMAL FIT 4 .681 STANDARD DEVIATION O 022 SAMPLE MINIMUM 0 462 SAMPLE MAXIMUM 0 .608 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE OUANTILES -S 3 4 5 6 7 *S 0 0 534 518 0.527 0.532 < 0.537> 0 SAMPLE AVERAGE 44 287 MODE FROM NORMAL FIT 0.3STANDARD DEVIATION 7 .366 STANDARD DEV. NORMAL FIT 0 027 SAMPLE MINIMUM 27 963 SAMPLE MAXIMUM 83 .671 MODE VALUE 42 .470 WORK DONE OURING COMPRESSION/EXPANSION STROKE .MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 6 7 • S 37 644 40 172 42. 134 < 44.090> 45.361 47.773 51.807 MODE FROM NORMAL FIT 43 .41 1 SAMPLE AVERAGE 8 269 STANDARD DEV. NORMAL FIT 8 .058 STANDARD DEVIATION 0 .468 SAMPLE MINIMUM 4 810 SAMPLE MAXIMUM 8 .582 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE OUANTILES -S 3 4 5 6 7 *S 8 8 385 161 8.252 8.323 < 8 364> 8SAMPLE AVERAGE 56 472 MODE FROM NORMAL FIT 8 .33STANDARD DEVIATION 9 .061 STANDARD DEV. NORMAL FIT 0 . 170 SAMPLE MINIMUM 34 018 SAMPLE MAXIMUM 87. 957 MODE VALUE 54 807 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES CRANKSHAFT OUANTILES -S 3 4 5 6 7 • S 48. 198 51.705 54 238 < 56.411> 5B.B51 61.897 70.642 MODE FROM NORMAL FIT 54 389 SAMPLE AVERAGE s 873 STANDARD DEV. NORMAL Fl :T I I .047 STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM 11 -25 46 .980 .019 .701 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE 10 .094 OUANTILES -S 3 4 5 6 7 *S -9539 -1.234 6.564 < 8.7B1> IO SAMPLE AVERAGE 18 169 MODE FROM NORMAL FIT 11 215 STANDARD DEVIATION 2 996 STANDARD DEV. NORMAL FIT 6 282 SAMPLE MINIMUM 6 468 SAMPLE MAXIMUM 26 .64 1 MODE VALUE 18 .446 FLAME TRAVEL BETWEEN PR0BE2 8 PROBE3 IN OEGREES CRANKSHAFT OUANTILES -S 3 4 5 6 7 *S 15 397 16.897 17. 623 < 1B.370> 18.824 19.590 20.818 MODE FROM NORMAL FIT 18 562 * SAMPLE AVERAGE 12 185 STANDARO DEV NORMAL FIT 2 448 STANOARD DEVIATION 9 680 SAMPLE MINIMUM -23 .530 SAMPLE MAXIMUM 44 .486 MODE VALUE 8 .353 OUANTILES -S 3 4 5 6 7 +S 3.2017.629 9.153 < 11.083> 13 MODE FROM NORMAL FIT 10 .280 STANDARD DEV. NORMAL FIT 6 .665 > 0.544 0.549 0.560 395 8.433 8.489 12.765 16.535 Experiment Ml.B P35 . LO CTi METHANE E N G I N E S P E E D 2 5 0 0 . 0 RPM AIR FLOW 1 0 0 . 0 X OF MAXIMUM R E L A T I V E A I R / F U E L R A T I O 0 . 9 SPARK ADVANCE 3 5 . 0 OEGR BTOC SPARK P L U G : STANDARD P L U G 35 MOMENT OF F L A M E A R R I V A L AT ION PROBE 1 MEASURED IN O E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 3 S . 6 5 1 > 4 3 . 6 4 2 4 6 . 7 6 1 5 0 . 9 7 1 MOMENT OF F L A M E A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MAXIMUM P E A K P R E S S U R E . M E A S U R E D IN BAR S A M P L E A V E R A G E 4 0 . 6 4 8 STANDARD D E V I A T I O N 9 .954 SAMPLE MINIMUM 22 . 5 9 9 S A M P L E MAXIMUM S3 .072 MODE V A L U E 33 . 3 0 8 O U A N T I L E S - S 3 4 5 6 7 »S 3 0 6 7 8 MODE FROM NORMAL F] [T 33 468 STANDARD D E V . NORMAL F I T 5 . 2 1 9 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * S MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T 3 4 . 8 2 7 4 . 3 1 9 2 3 . 7 5 1 4 6 . 6 1 9 3 4 . 4 7 0 3 0 . 4 7 7 3 2 . 4 3 5 3 3 . 5 0 8 3 4 . 7 9 9 6 . 145 < 3 4 . 6 3 1 > 3 5 . 7 9 9 3 7 . 0 1 4 3 9 . 2 6 8 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 45 . 0 5 5 STANDARD D E V I A T I O N 7 578 SAMPLE MINIMUM 28 . 6 5 9 SAMPLE MAXIMUM 78 . 0 8 8 MODE V A L U E 41 531 O U A N T I L E S - S 3 4 5 6 7 * S 37 . 7 8 2 MODE FROM NORMAL F I T 42 . 497 STANDARD D E V . NORMAL F I T 5 .202 S A M P L E A V E R A G E O 518 STANDARD D E V I A T I O N 0 . 021 S A M P L E MINIMUM 0 . 4 5 9 S A M P L E MAXIMUM 0 . 578 MODE V A L U E 0 . 5 1 0 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 496 MODE FROM NORMAL F I T 0 . 518 STANDARD D E V . NORMAL F I T 0 0 2 6 0 . 5 0 7 0 . 5 1 2 < 0 . 5 1 8 > 0 . 5 2 3 0 5 2 9 0 . 5 4 0 < 4 3 . 9 4 6 > 4 6 . 2 4 3 4 8 . 8 3 3 5 2 . 7 1 2 MOMENT OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 5 7 . 5 6 5 > 5 9 532 62 366 6 9 . 3 4 1 MOMENT OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC S A M P L E A V E R A G E 57 624 STANDARO D E V I A T I O N 9 3 1 0 SAMPLE MINIMUM 4 0 . t 2 0 S A M P L E MAXIMUM 91 . 6 2 0 MODE V A L U E 52 . 4 5 9 O U A N T I L E S - S 3 4 5 6 7 * S 48 . 2 0 0 MODE FROM NORMAL F] [T 55 . 6 3 0 STANDARD O E V . NORMAL F I T 12 .214 WORK DONE D U R I N G C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 8 2 8 3 S T A N D A R O D E V I A T I O N 0 . 1 7 0 S A M P L E MINIMUM 7 . 2 5 9 S A M P L E MAXIMUM 8 . 5 8 7 MODE V A L U E 8 . 3 5 2 O U A N T I L E S - S 3 4 5 8 7 * S 8 . 1 0 6 MODE FROM NORMAL F I T 8 . 3 5 7 STANDARD O E V . NORMAL F I T 0 . 1 6 3 B . 2 2 7 8 . 2 7 6 < 8 . 3 1 7 > 8 . 3 5 5 8 . 3 9 3 8 . 4 4 5 FLAME T R A V E L B E T W E E N PROBE 1 8 P R 0 B E 2 IN O E G R E E S C R A N K S H A F T S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T STANDARO O E V . NORMAL F I T 1 9 . 5 1 1 2 . 8 6 9 1 2 . 1 1 3 2 9 . 4 2 9 1 8 . 4 2 6 * S 1 6 . 4 8 9 S A M P L E A V E R A G E 4 . 4 0 7 S T A N D A R D D E V I A T I O N 12 112 S A M P L E MINIMUM - 4 3 532 S A M P L E MAXIMUM 37 . 8 3 0 MODE V A L U E 11 . 5 5 7 O U A N T I L E S - S 3 4 5 6 7 » S - 8 .271 MODE FROM NORMAL F I T 5. .431 STANDARD D E V . NORMAL F I T 16 . 9 5 0 - 3 . 9 3 0 1 . 7 9 7 < 6 . 4 3 3 > 9 . 5 9 5 1 1 . 5 6 6 15 .221 1 8 . 1 4 0 1 8 . 6 0 9 < 1 9 . 5 2 l > 2 0 . 2 6 7 2 1 . 1 4 1 22 431 FLAME T R A V E L B E T W E E N P R 0 B E 2 8 P R 0 B E 3 IN D E G R E E S C R A N K S H A F T 19 809 S A M P L E A V E R A G E 12 . 5 6 9 3 126 STANDARD D E V I A T I O N 8 8 3 6 S A M P L E MINIMUM - 16. . 407 S A M P L E MAXIMUM 41 6 3 7 MODE V A L U E 9 . 592 O U A N T I L E S - S 3 4 5 6 7 +S 4 .761 MODE FROM NORMAL F I T 9 8 5 9 S T A N D A R D D E V . NORMAL F I T 5 739 7 . 8 2 7 9 . 5 6 9 < 1 1 . t O O > 1 3 . 9 3 8 1 6 . 6 5 9 2 0 . 9 6 5 Experiment Ml.D P 3 5 METHANE ENGINE S P E E D AIR FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 2 4 4 0 . 0 RPM 1 O O . 0 % OF MAXIMUM 1 .3 4 5 . 0 DEGR BTDC SPARK P L U G : STANDARD P L U G 35 MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 45 0 5 6 STANDARD D E V I A T I O N e .231 S A M P L E MINIMUM 30 235 S A M P L E MAXIMUM 7 6 . . 788 MODE V A L U E 4 4 . 298 O U A N T I L E S - S 3 4 5 6 7 * S 37 365 MODE FROM NORMAL F I T 4 3 . 832 STANDARD D E V . NORMAL F I T 8 . 153 . 1 6 0 < 4 4 I 3 6 > 4 5 . 9 4 1 4 8 . 4 4 3 5 2 . 0 6 5 MOMENT OF FLAME A R R I V A L AT ION PROBE 2 MEASURED I N . D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 66 . 154 STANDARD D E V I A T I O N 22 . 0 6 0 SAMPLE MINIMUM 0 6 1 6 SAMPLE MAXIMUM 124 . 7 9 7 MODE V A L U E 61 . 4 1 3 O U A N T I L E S - S 3 4 5 6 7 * S 5 0 0 5 7 MODE FROM NORMAL F I T 61 . 2 2 7 STANDARD D E V . NORMAL F I T 16 . 597 MOMENT OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 75 205 STANDARO D E V I A T I O N 18 881 SAMPLE MINIMUM 5 . 191 S A M P L E MAXIMUM 121 . 141 MODE V A L U E 66 . 7 8 9 O U A N T I L E S - S 3 4 5 6 7 » S 6 0 .471 MODE FROM NORMAL F I T 68 9 0 8 STANDARO D E V . NORMAL F I T 13. 423 6 6 . 1 8 6 6 9 . 1 9 7 < 7 3 . 0 6 7 > 7 6 . 9 3 7 8 3 . 2 8 7 9 2 . 4 7 0 MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR SAMPLE A V E R A G E STANDARO D E V I A T I O N SAMPLE MINIMUM SAMPLE MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T 3 1 . 3 2 5 5 . 9 6 9 1 7 . 8 5 1 4 6 . 7 7 1 2 9 . 6 0 0 +S 2 4 . 9 4 9 2 7 . 8 5 8 2 9 . 5 4 8 32 . 357 < 3 1 . 2 5 0 > 3 3 . 0 3 3 3 4 . 8 8 3 3 7 . 6 6 9 STANDARD D E V . NORMAL F I T 9 . 4 4 0 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR IMEP) S A M P L E A V E R A G E 0 . 4 7 9 STANDARD D E V I A T I O N 0 . 0 1 9 SAMPLE MINIMUM 0 . 4 1 4 SAMPLE MAXIMUM 0 . 5 3 9 MODE V A L U E 0 . 4 8 5 O U A N T I L E S - S 3 4 5 6 7 * S 0 457 MODE FROM NORMAL F I T 0 . 4 8 t STANDARD D E V . NORMAL F I T 0 . 0 1 6 0 . 4 6 9 0 . 4 7 5 < 0 . 4 B 0 > 0 . 4 8 5 0 . 4 8 9 0 . 4 9 8 WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N STROKE . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 6 . 8 2 9 STANDARD O E V I A T I O N 0 . 6 8 0 SAMPLE MINIMUM 0 . 1 2 4 SAMPLE MAXIMUM 7 . 6 2 2 MODE V A L U E 7 . 0 7 5 O U A N T I L E S - S 3 4 5 6 7 * S 6 . 4 9 1 MODE FROM NORMAL F I T 7 . 0 3 8 STANDARD D E V . NORMAL F I T 0 . 3 2 9 6 . 7 9 6 6 . 9 2 6 < 7 . 0 1 7 > 7 . 0 7 7 7 . 1 3 5 7 . 2 2 2 MOMENT OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC S A M P L E A V E R A G E 1 6 . 5 9 7 STANDARD D E V I A T I O N 6 . 3 4 5 S A M P L E MINIMUM I 9 8 6 S A M P L E MAXIMUM 1 2 4 . 6 4 5 MODE V A L U E 1 6 . 0 4 0 O U A N T I L E S - S 3 4 5 6 7 »S 1 3 . 7 3 3 1 4 . 8 5 5 1 5 . 7 9 5 < 1 6 . 2 6 2 > 1 7 . 0 6 6 17 797 1 9 . 0 5 5 MODE FROM NORMAL F I T 16 129 STANDARD D E V . NORMAL F I T 3 . 4 4 5 E x p e r i m e n t M l . E P35 LO 00 METHANE ENGINE S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 4 0 . 0 DEGR B T D C SPARK P L U G : STANDARD P L U G 35 2 5 0 0 . 0 RPM 1 0 0 . 0 % OF MAXIMUM MOMENT OF FLAME A R R I V A L AT ION PROBE I MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 38 9 5 7 STANDARD D E V I A T I O N 9 132 SAMPLE MINIMUM 24 . 327 S A M P L E MAXIMUM 65 458 MODE V A L U E 34 181 O U A N T I L E S - S 3 4 5 6 7 » S 31 . 2 2 5 3 3 . 5 4 4 34 MODE FROM NORMAL F I T 35 . 109 STANDARD O E V . NORMAL F I T 6 . 166 OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN S A M P L E A V E R A G E 51 4 9 9 STANDARD D E V I A T I O N 10 0 6 4 S A M P L E MINIMUM 29 6 9 3 SAMPLE MAXIMUM 86 .944 MOOE V A L U E 45 795 O U A N T I L E S - 5 3 4 5 6 7 * S 41 .291 4 5 . 4 4 2 47 MOOE FROM NORMAL F I T 47 228 STANDARD D E V . NORMAL FI [T 1 1 127 OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN S A M P L E A V E R A G E 57 522 STANDARD D E V I A T I O N 7 932 S A M P L E MINIMUM 38 0 0 9 S A M P L E MAXIMUM 92 9 5 8 MODE V A L U E 53 4 6 3 O U A N T I L E S - S 3 4 5 6 7 • S 5 0 0 2 2 5 3 . 5 7 6 54 MODE FROM NORMAL F I T 55 5 7 0 STANDARO D E V . NORMAL F I T 6 478 MOMENT OF MAXIMUM P E A K P R E S S U R E . MEASURED IN O E G R E E S C R A N K 5 H A F T A F T E R TDC S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * ' . MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T 16 8 8 5 2 . 7 3 3 6 . 8 3 7 22 694 1 7 . 9 0 4 1 4 . 1 7 0 1 5 . 4 0 3 1 6 . 1 3 1 1 6 . 7 3 3 2 . 7 0 4 < 1 6 . 9 4 2 > 1 7 . 7 5 8 1 8 . 1 4 7 1 9 . 8 3 0 MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM . MOOE VALUE O U A N T I L E S - S 3 4 5 6 7 * S MODE FROM NORMAL F I T STANDARD O E V . NORMAL F I T 3 5 . 3 0 0 4 . 143 2 3 . 4 1 5 4 6 . 3 7 9 3 5 . 6 1 4 3 1 . 0 1 1 3 2 . 9 6 3 3 4 . 3 4 1 3 4 . 5 5 3 4 . 3 6 0 < 3 5 . 3 2 5 > 3 6 . 1 9 4 3 7 . 4 2 5 3 9 . 5 7 8 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 . 5 3 8 STANDARD D E V I A T I O N 0 . 0 1 9 S A M P L E MINIMUM 0 . 4 7 5 S A M P L E MAXIMUM 0 . 6 0 1 MODE V A L U E 0 . 5 4 7 O U A N T I L E S - S 3 4 5 6 7 * S O . 5 2 0 MODE FROM NORMAL F I T 0 . 5 3 8 STANDARD D E V . NORMAL F I T 0 . 0 2 5 0 . 5 2 8 0 . 5 3 3 < 0 . 5 3 9 > 0 . 5 4 4 0 . 5 4 9 0 . 5 5 8 WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 7 . 8 7 3 STANDARD D E V I A T I O N 0 . 1 1 3 S A M P L E MINIMUM 7 . 2 8 8 S A M P L E MAXIMUM 8 . 0 9 6 MODE V A L U E 7 . 9 3 6 O U A N T I L E S - S 3 4 5 6 7 * S 7 . 7 6 7 MODE FROM NORMAL F I T 7 . 9 2 8 STANDARD O E V . NORMAL F I T O . O 8 0 7 . 8 3 6 7 . 8 7 4 < 7 . 9 0 5 > 7 . 9 2 6 7 . 9 4 1 7 . 9 8 1 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 B E 2 IN D E G R E E S C R A N K S H A F T S A M P L E A V E R A G E 12 . 5 4 2 STANDARD D E V I A T I O N . 13 . 366 S A M P L E MINIMUM - 2 1 . 305 S A M P L E MAXIMUM S O . 5 8 4 MODE V A L U E 12 . 393 O U A N T I L E S - S 3 4 5 8 7 * S -1 . 184 MODE FROM NORMAL F I T 14 . 2 4 9 STANDARD D E V . NORMAL F I T 11 . 383 7 . 9 2 6 1 0 . 6 5 0 < 1 3 S 6 6 > 1 6 . 1 3 1 1 9 . 1 5 4 2 5 . 0 0 8 FLAME T R A V E L B E T W E E N P R 0 B E 2 8 P R 0 8 E 3 IN D E G R E E S C R A N K S H A F T S A M P L E A V E R A G E 6 . 0 2 2 STANDARD D E V I A T I O N l O . 0 4 5 S A M P L E MINIMUM - 2 3 . 0 5 2 SAMPLE MAXIMUM 32 . 5 7 7 MOOE V A L U E 5 . 3 4 2 O U A N T I L E S - S 3 4 5 6 7 « S - 4 . 5 6 9 MODE FROM NORMAL F I T 7 .491 STANDARD O E V . NORMAL F I T 7 . 9 3 7 1 . 6 4 9 4 . 3 1 8 < 6 . 6 0 2 > 8 . 5 6 7 1 1 . 6 2 3 1 6 . 4 4 9 Experiment Ml.F P35 KD KD METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 2500.0 RPM tOO.O % OF MAXIMUM 1. 2 MAXIMUM PEAK PRESSURE. MEASURED IN BAR ADVANCE 40 .0 DEGR BTDC SAMPLE AVERAGE 34 . 104 PLUG: STANDARD PLUG 35 STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM 4 25 45 .268 .545 .016 ' OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 36 . 295 OUANTILES -S 3 4 5 6 7 »S 29 .669 31.437 32.985 < 34.0O5> 35 SAMPLE AVERAGE 39 .228 MOOE FROM NORMAL FIT 33 .325 STANDARO DEVIATION 6 .672 STANDARD DEV. NORMAL FIT 5 .651 SAMPLE MINIMUM 26 .890 SAMPLE MAXIMUM 71 .701 MODE VALUE 35 .758 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 e 7 *S 33 . 1 15 35.288 36 .855 < 38.195> 39.395 42.006 46 839 MODE FROM NORMAL FIT 36 .737 SAMPLE AVERAGE 0 .498 STANDARD DEV. NORMAL FIT 5 .260 STANDARD DEVIATION 0 .018 SAMPLE MINIMUM 0 .444 SAMPLE MAXIMUM 0 .547 OF FLAME ARRIVAL AT ION PROBE 2 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION MOOE VALUE 0 .501 OUANTILES -S 3 4 5 6 7 *S 0 .479 0.488 0.494 < 0.499> 0 SAMPLE AVERAGE 56 .431 MODE FROM NORMAL FIT 0 .499 STANDARD DEVIATION 11 .692 STANDARD DEV. NORMAL FIT 0 .026 SAMPLE MINIMUM 33 .044 SAMPLE MAXIMUM 93 .801 MODE VALUE 53 .929 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) OUANTILES -S 3 4 3 6 7 +S 44 .632 49.175 52 416 < 55.471> 59.084 62 638 69.774 MODE FROM NORMAL FIT 53 .546 SAMPLE AVERAGE 7 .521 STANDARD DEV. NORMAL FIT 15 309 STANDARD DEVIATION 0 . 161 SAMPLE MINIMUM 6 .805 SAMPLE MAXIMUM 7 828 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 7 .626 OUANTILES -S 3 4 5 6 7 *S 7 .360 7.439 7.510 < 7.555> 7. SAMPLE AVERAGE 64 189 MODE FROM NORMAL FIT 7 595 STANDARD DEVIATION 9 900 STANDARD DEV. NORMAL FIT 0 142 SAMPLE MINIMUM 45. 232 SAMPLE MAXIMUM 94 625 MOOE VALUE 64 269 FLAME TRAVEL BETWEEN PROBE 1 8 PROBE2 IN DEGREES CRANKSHAFT OUANTILES - 5 3 4 5 6 7 »S 55. 216 58.189 60. 728 < 63.227> 65.192 67.875 74 328 MODE FROM NORMAL FIT 61 . 324 SAMPLE AVERAGE 17 203 STANDARO DEV. NORMAL FIT 9. 847 STANDARD DEVIATION 12 471 SAMPLE MINIMUM • 19. 663 SAMPLE MAXIMUM 59. 712 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MOOE VALUE 10. 928 OUANTILES -S 3 4 S 6 7 *S 6. 684 tO.B46 13.454 < 16.330> 19. SAMPLE AVERAGE 17 . 532 MODE FROM NORMAL FIT 13. 840 STANDARD DEVIATION 2. 444 STANDARD DEV. NORMAL FIT 8 921 SAMPLE MINIMUM 10. 325 SAMPLE MAXIMUM 23. 038 MODE VALUE 18. 138 OUANTILES -S 3 4 5 e 7 *S 15. 108 16.290 17 . 095 < 17.523> 18.170 18.657 20.046 MOOE FROM NORMAL FIT 17 . 451 STANDARD OEV. NORMAL FIT 2. 018 503 0.509 0.518 596 7.628 7.691 E x p e r i m e n t M l . G P35 o o METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 2500.0 RPM 100.0 % OF MAXIMUM t . 2 45.0 DEGR BTDC MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 41 933 STANDARD DEVIATION e. 423 SAMPLE MINIMUM 26. 121 SAMPLE MAXIMUM 98 822 MODE VALUE 36 995 ' OUANTILES -S 3 4 5 6 7 »S 35. 624 37.558 38.954 < 40.488> 4 1.928 43 MODE FROM NORMAL Fl [T 38. 986 STANDARD DEV. NORMAL FIT 6. 385 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT 37.007 4 . 220 17.50O 47.415 36.508 +S 32.922 34.678 35.966 36.984 < 36.862> 38.052 39.156 41.377 STANDARD DEV. NORMAL FIT 5.236 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION < 55.052> 57.654 62.637 71.407 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 56 186 STANDARD DEVIATION 10 .874 SAMPLE MINIMUM 34 .579 SAMPLE MAXIMUM 99 .026 MODE VALUE 54 .047 OUANTILES -S 3 4 5 6 7 *S 46 327 MODE FROM NORMAL FIT 51 .627 STANDARD OEV. NORMAL FIT 7 .843 WORK DONE DURING INTAKE/EXHAUST STROKE,MEASUREO IN BAR (MEP) SAMPLE AVERAGE 0.510 STANDARD DEVIATION 0.020 SAMPLE MINIMUM 0.-153 SAMPLE MAXIMUM 0.564 MODE VALUE 0.517 OUANTILES -S 3 4 5 6 7 +S 0.489 MODE FROM NORMAL FIT 0.511 STANDARD DEV. NORMAL FIT 0.025 0.499 0.505 < 0.512> 0.517 0.522 0.531 SAMPLE AVERAGE 62 .873 STANDARD DEVIATION 8 .961 SAMPLE MINIMUM 43 .078 SAMPLE MAXIMUM 94 246 MODE VALUE 59 .601 OUANTILES -S 3 4 5 6 7 *S 54 .516 MODE FROM NORMAL FIT 61 .335 STANDARO DEV. NORMAL FIT 8 850 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.435 STANDARD DEVIATION 0.483 SAMPLE MINIMUM 2.202 SAMPLE MAXIMUM 7.885 MODE VALUE 7.471 OUANTILES -S 3 4 5 6 7 *S 7.371 MODE FROM NORMAL FIT 7.486 STANDARD DEV. NORMAL FIT 0.161 7.442 7.478 < 7.509> 7.532 7.564 7.639 < 62.033> 64.145 66.909 71.372 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARO DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MOOE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 15.847 2.859 1 .631 22.669 16.314 »S 13 206 14.616 15.368 16.088 2.695 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 14.252 STANDARD DEVIATION 13.343 SAMPLE MINIMUM -62.239 SAMPLE MAXIMUM 51.014 MODE VALUE 9.724 OUANTILES -S 3 4 5 6 7 *S 3.901 MODE FROM NORMAL FIT 12.941 8.584 11.152 < 13.724> 16.555 19.908 26 412 STANOARD DEV. NORMAL FIT 11.395 < 15.975> 16.518 17.430 18.456 E x p e r i m e n t M l . H P35 2 5 0 0 . 0 RPM 1 O O . 0 % OF MAXIMUM METHANE E N G I N E S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O 1.2 S P A R K ADVANCE 3 5 . 0 DEGR B T D C SPARK P L U G : STANDARD P L U G 35 MOMENT OF F L A M E A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 3 6 . 9 5 1 > 3 8 . 3 3 3 3 9 . 8 3 8 4 2 . 9 7 9 MOMENT OF F L A M E A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR SAMPLE A V E R A G E 37 . 277 STANDARD D E V I A T I O N 5 0 7 8 SAMPLE MINIMUM 24 .474 S A M P L E MAXIMUM 56 2 2 0 MODE V A L U E 35 386 O U A N T I L E S - S 3 4 5 6 7 * S 32 237 MOOE FROM NORMAL F I T 35 . 7 2 0 STANDARD D E V . NORMAL F I T 5 . 155 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T 2 9 . 4 6 4 3 . 6 5 0 2 0 . 6 6 9 4 1 . 8 1 6 28 379 +S 2 5 . 5 8 2 2 7 . 2 1 9 2 8 . 2 0 3 2 8 . 2 5 2 < 2 9 . 0 7 5 > 3 0 . 1 6 4 3 1 . 0 3 6 3 3 . 1 7 3 STANDARD D E V . NORMAL F I T 4 . 7 2 4 S A M P L E A V E R A G E STANDARD D E V I A T I O N SAMPLE MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 6 0 . 0 1 9 1 4 . 0 1 5 3 2 . 5 5 4 1 1 6 . 9 7 6 5 2 . 7 8 0 * S 4 6 . 5 4 5 5 1 . 5 4 3 5 4 . 5 3 2 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 . 4 8 8 S T A N D A R D D E V I A T I O N 0 . 0 1 9 S A M P L E MINIMUM 0 . 4 3 7 S A M P L E MAXIMUM 0 . 5 4 4 MOOE V A L U E 0 . 4 9 2 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 4 7 0 MODE FROM NORMAL F I T 0 . 4 9 6 STANDARO D E V . NORMAL F I T 0 . 0 2 4 0 . 4 7 8 0 . 4 8 3 < 0 . 4 8 9 > 0 . 4 9 4 0 . 4 9 9 0 . 5 0 9 5 8 . 1 0 8 > 6 1 . 7 2 7 6 6 . 7 6 7 7 7 . 4 4 7 WORK DONE D U R I N G C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D I N BAR ( M E P ) MODE FROM NORMAL F I T 54 294 S A M P L E A V E R A G E 7 . 292 STANDARD D E V . NORMAL F I T 14 . 5 3 6 STANDARD D E V I A T I O N 0 251 S A M P L E MINIMUM 6 231 S A M P L E MAXIMUM 7. 7 2 0 OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MODE V A L U E 7 , 364 O U A N T I L E S - S 3 4 5 6 7 * S 7 041 7 . 2 0 9 S A M P L E A V E R A G E 67 536 MODE FROM NORMAL F I T 7 . 3 8 0 STANDARD D E V I A T I O N 11 .771 STANDARD O E V . NORMAL F I T 0 247 SAMPLE MINIMUM 41 183 SAMPLE MAXIMUM 125 . 4 3 8 MODE V A L U E 61 . 3 6 9 FLAME T R A V E L B E T W E E N PROBE 1 8 PROBE2 IN O E G R E E S O U A N T I L E S - S 3 4 5 6 7 * S 55 .991 6 0 . 1 8 9 6 2 . 8 8 6 < 6 5 . 9 4 2 > 6 9 . 1 2 8 7 2 . 9 7 1 8 0 . 7 7 6 MODE FROM NORMAL F I T 63 . 7 2 5 S A M P L E A V E R A G E 22 741 STANDARO D E V . NORMAL F I T 11 0 0 7 STANDARD D E V I A T I O N 12 9 6 9 S A M P L E MINIMUM - 6 396 S A M P L E MAXIMUM 75 6 2 2 OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC MODE V A L U E 13 . 254 O U A N T I L E S - S 3 4 5 6 7 * S 10 . 5 5 3 1 3 . 5 1 0 S A M P L E A V E R A G E 18 . 3 2 7 MODE FROM NORMAL F I T 16 237 STANDARO O E V I A T I O N 2 . 7 2 0 STANDARD D E V . NORMAL F I T 9 . 6 2 0 SAMPLE MINIMUM 7 . 195 SAMPLE MAXIMUM 27 . 3 2 6 MODE V A L U E 17 . 8 8 9 O U A N T I L E S - S 3 4 5 6 7 »S 15 . 5 2 0 1 6 . 9 7 6 1 7 . 6 5 7 < 1 8 . 0 6 1 > 18 875 1 9 . 7 4 8 2 1 . 8 7 3 MODE FROM NORMAL F I T 17 827 S T A N D A R D D E V . NORMAL F I T 1 . 746 7 . 2 6 8 < 7 . 3 4 0 > 7 . 3 B 6 7 . 4 6 0 7 536 < 1 9 . 3 4 5 > 2 3 . 3 2 5 2 7 . 9 0 7 3 7 . 7 7 4 E x p e r i m e n t M l . I P35 o METHANE E N G I N E S P E E D AIR FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 2 5 0 0 . 0 RPM 6 5 . 0 X OF MAXIMUM 1 . 0 3 5 . 0 DEGR B T D C MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR SPARK P L U G : STANDARD P L U G 35 MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 3 2 . 9 9 3 > 3 4 . 8 3 7 3 6 . 1 0 9 4 1 . 0 4 1 MOMENT OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N SAMPLE A V E R A G E 33 158 STANDARD D E V I A T I O N 7 . 9 2 2 SAMPLE MINIMUM 23 . 103 SAMPLE MAXIMUM 73 8 5 2 MODE V A L U E 3 2 . 0 9 0 O U A N T I L E S - S 3 4 5 6 7 * S 28 8 7 6 MODE FROM NORMAL F I T 3 1 . . 997 STANDARD D E V . NORMAL F I T 4 . 2 4 9 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 3 6 7 * S MODE FROM NORMAL F I T STANDARD O E V . NORMAL F I T 2 3 . 8 2 8 2 . 6 7 6 1 4 . 7 3 2 2 7 . 0 5 2 2 6 . 6 6 7 2 0 . 7 5 4 2 2 . 4 5 2 2 3 . 5 6 3 2 6 . 6 5 B 0 . 4 6 5 < 2 4 . 3 7 2 > 2 5 . 1 1 0 2 5 . 9 5 0 2 6 . 6 7 1 S A M P L E A V E R A G E 47 . 9 8 9 STANDARO D E V I A T I O N 9 287 SAMPLE MINIMUM 29 4 2 9 SAMPLE MAXIMUM 83 . 4 2 5 MODE V A L U E 44 . 6 1 6 O U A N T I L E S - S 3 4 3 6 7 * S 39 . 0 4 8 MODE FROM NORMAL F I T 4 5 .231 STANDARD O E V . NORMAL F I T 10 . 4 5 6 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 512 STANDARD D E V I A T I O N 0 . 0 1 4 S A M P L E MINIMUM 0 . 4 6 1 S A M P L E MAXIMUM 0 . 5 5 3 MODE V A L U E 0 . 5 1 2 O U A N T I L E S - S 3 4 3 6 7 * S 0 498 MODE FROM NORMAL F I T 0 . 5 1 1 STANDARD D E V . NORMAL F I T 0 . 0 1 8 0 . 5 0 5 O . 5 0 9 < 0.513> 0 . 5 1 6 0 . 5 2 0 0 . 5 2 7 < 4 7 . 0 5 5 > 49 221 52 046 5 7 . 1 0 6 MOMENT OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N SAMPLE A V E R A G E STANDARD D E V I A T I O N SAMPLE MINIMUM SAMPLE MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 i 6 3 . 3 0 2 1 1 . 2 6 5 4 1 . 7 5 3 1 0 1 . 0 3 8 5 9 . 6 6 2 • S 5 2 . 0 9 5 5 6 . 9 2 7 5 9 . 4 3 6 < 6 2 . 0 4 0 > WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N STROKE . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 3 . 6 0 6 STANDARD D E V I A T I O N 0 . 1 1 0 S A M P L E MINIMUM 4 . 9 9 2 S A M P L E MAXIMUM 5 . B I O MODE V A L U E 5 . 6 4 8 O U A N T I L E S - S 3 4 3 6 7 » S 5 . 5 1 8 MODE FROM NORMAL F I T 5 . 6 4 9 STANDARD D E V . NORMAL F I T 0 . 0 9 0 5 . 5 8 1 5 . 6 1 2 < 5 . 6 3 7 > 5 . 6 5 4 5 . 6 8 2 5 . 7 2 3 6 5 . 0 1 8 6 8 . 3 1 7 7 5 . 0 0 0 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 B E 2 IN O E G R E E S C R A N K S H A F T MOOE FROM NORMAL F I T 6 0 . 8 5 2 S A M P L E A V E R A G E 12 .831 STANDARD O E V . NORMAL F I T 1 2 . 1 3 3 S T A N D A R D D E V I A T I O N 10 5 9 0 S A M P L E MINIMUM - 2 5 . 7 1 5 S A M P L E MAXIMUM 45 .442 OF MAXIMUM P E A K P R E S S U R E , MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC MODE V A L U E 12 087 O U A N T I L E S - S 3 4 5 8 7 » S 4 . 837 SAMPLE A V E R A G E 1 8 . 9 6 0 MODE FROM NORMAL F I T 12 .442 STANDARD O E V I A T I O N 2 . 9 1 4 STANDARD D E V . NORMAL F I T 7 . 0 2 5 SAMPLE MINIMUM 10 5 3 9 S A M P L E MAXIMUM 26 888 MODE V A L U E 1 8 . 5 4 3 F L A M E T R A V E L B E T W E E N P R O B E 2 8 > P R O B E S IN D O U A N T I L E S - S 3 4 5 6 7 * S 1 6 . 3 5 0 1 7 . 5 7 6 1 8 . 1 5 9 < 18 .813> 1 9 . 6 4 9 2 0 . ( 182 2 2 . 2 7 9 MODE FROM NORMAL F I T 1 8 . 7 1 0 S A M P L E A V E R A G E 15 . 3 1 3 STANDARD D E V . NORMAL F I T 2 . 7 0 9 STANDARD O E V I A T I O N 10 224 S A M P L E MINIMUM - 1 9 362 S A M P L E MAXIMUM 41 . 8 2 5 MODE V A L U E 15. 693 O U A N T I L E S - S 3 4 5 6 7 * S S 246 MODE FROM NORMAL F I T 15. 385 STANDARD D E V . NORMAL F I T 12 061 8 . 8 2 2 1 0 . 8 3 8 < 1 2 . 5 2 7 > 1 4 . 3 6 0 1 7 . 4 3 6 2 1 . 8 3 6 9 . 6 7 5 1 2 . 5 8 S < 1 5 . 5 5 7 > 1 7 . 7 3 1 2 0 . 5 1 8 2 4 . 6 0 3 Experiment Ml.J P35 METHANE ENGINE S P E E D A I R PLOW R E L A T I V E A I R / F U E L R A T I O 2 5 0 0 . 0 RPM 6 5 . 0 % OF MAXIMUM 1 . 1 MAXIMUM P E A K P R E S S U R E . M E A S U R E D IN BAR ADVANCE 3 5 . 0 DEGR BTDC S A M P L E A V E R A G E 22 978 P L U G : STANDARD P L U G 35 S T A N D A R D D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM 2 16 27 639 . 746 . 245 OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * S 26 19 . 9 1 7 . 8 8 3 2 1 . 5 7 1 2 2 . 2 3 0 < 2 3 . 0 6 B > 23 S A M P L E A V E R A G E 35 . 7 0 7 MODE FROM NORMAL F I T 24 . 0 1 5 STANDARD D E V I A T I O N ' .5 . 8 5 0 S T A N D A R D O E V . NORMAL F I T 4 . 736 SAMPLE MINIMUM 23 . 1 12 SAMPLE MAXIMUM 61 . 8 1 8 MODE V A L U E 33 998 WORK DONE D U R I N G I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) O U A N T I L E S - S 3 A 5 € 7 • S 30 . 7 0 2 3 2 . 5 4 2 34 . 0 1 3 < 3 5 . 0 0 6 > 3 5 . 8 7 3 3 7 . 5 7 3 4 1 . 2 8 7 MODE FROM NORMAL F I T 33 .741 S A M P L E A V E R A G E 0 . 4 6 6 STANDARD D E V . NORMAL F I T 3 . 9 5 9 S T A N D A R D D E V I A T I O N 0 . 0 1 5 S A M P L E MINIMUM 0 . 4 2 8 S A M P L E MAXIMUM O . 5 1 6 OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * S O.O . 4 6 0 .451 0 . 4 5 9 0 . 4 6 2 < 0 . 4 6 6 > 0 S A M P L E A V E R A G E 53 . 2 4 3 MODE FROM NORMAL F I T 0 . 4 6 7 STANDARD D E V I A T I O N 1 1 . 8 9 8 S T A N D A R D O E V . NORMAL F I T 0 . 0 1 7 S A M P L E MINIMUM 33 . 9 7 2 S A M P L E MAXIMUM • 91 . 4 6 7 MODE V A L U E 44 . 153 WORK DONE D U R I N G C O M P R E S S I O N / E X P A N S I O N STROKE . M E A S U R E D IN BAR ( M E P ) O U A N T I L E S - S 3 A 5 6 7 * S 41 . 7 6 4 4 4 . 9 3 7 4B .551 < 5 1 . 4 8 8 > 5 4 . 1 9 7 5 7 . 9 9 5 6 6 . 4 5 8 MODE FROM NORMAL F I T 48 . 0 1 7 S A M P L E A V E R A G E 5 . 2 0 2 STANDARD D E V . NORMAL F l :T I i . 2 3 4 S T A N D A R D D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM 0 4 5 . 139 . 5 7 2 . 4 2 5 OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 * S 5 5 . 3 0 9 . 067 5 . 1 6 6 5 . 2 0 7 < 5 . 2 3 8 > 5 . S A M P L E A V E R A G E 7 0 . 8 0 3 MODE FROM NORMAL F I T 5 . 277 STANDARD D E V I A T I O N 14 . 2 6 4 S T A N D A R D D E V . NORMAL F I T O . 117 S A M P L E MINIMUM 45 .561 S A M P L E MAXIMUM 115 . 0 1 2 MODE V A L U E 67 . 9 8 8 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 8 E 2 IN D E G R E E S C R A N K S H A F T O U A N T I L E S - S 3 4 5 6 7 * S 55 .951 6 3 . 2 3 6 67 . 0 1 6 < 7 0 . 4 8 9 > 7 4 . 5 2 1 7 7 . 8 9 7 8 9 . B 5 0 MODE FROM NORMAL F I T 66 . 5 7 3 S A M P L E A V E R A G E 17 534 STANDARD D E V . NORMAL F I T 17 .524 S T A N D A R D D E V I A T I O N 12 292 S A M P L E MINIMUM 2 0 6 8 3 S A M P L E MAXIMUM 52 515 OF MAXIMUM P E A K P R E S S U R E : . MEASURED IN O E G R E E S C R A N K S H A F T A F T E R TDC MODE V A L U E 12 104 O U A N T I L E S - S 3 4 5 6 7 » S 6 814 1 0 . 9 1 3 1 3 . 0 6 5 < 1 5 . 6 0 1 > 18 SAMPLE A V E R A G E 19 0 1 7 MODE FROM NORMAL F I T 13 325 STANDARO D E V I A T I O N 2. . 787 S T A N D A R D D E V . NORMAL F I T IO. 784 SAMPLE MINIMUM 11 . . 115 SAMPLE MAXIMUM 26 369 MODE V A L U E 18 901 FLAME T R A V E L B E T W E E N P R O B E 2 8 P R O B E S IN D E G R E E S C R A N K S H A F T O U A N T I L E S - S 3 4 5 6 7 • S 16. 0 7 4 1 7 . 9 1 5 18 724 < 1 9 . 0 5 7 > 1 9 . 5 8 6 2 0 . 1 0 0 21 683 MODE FROM NORMAL F I T 19. 292 S A M P L E A V E R A G E 17 . 5 6 0 STANDARD D E V . NORMAL F I T 1 230 S T A N D A R D D E V I A T I O N 14 . 431 S A M P L E MINIMUM 2 4 . 421 S A M P L E MAXIMUM 6 0 5 9 0 MOOE V A L U E 13. 6 5 7 O U A N T I L E S - S 3 4 5 6 7 * S 3 473 9 . 7 5 0 1 3 . 2 6 7 < 1 6 . 5 4 9 > 2 0 . MODE FROM NORMAL F I T 15. 3 3 9 S T A N D A R D D E V . NORMAL F I T 14 . 6 9 6 . 4 7 0 0 . 4 7 3 0 . 4 8 0 269 5 . 3 0 5 5 . 3 3 6 . 8 8 4 2 2 . 0 6 0 2 9 . 8 8 0 Experiment Ml.K P35 METHANE E N G I N E S P E E D AIR FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 3 0 0 O . 0 RPM 1 O 0 . O % OF MAXIMUM t . 0 4 0 . 0 OEGR B T D C SPARK P L U G : STANDARD P L U G 35 MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 35 5 8 9 STANDARD D E V I A T I O N 4 277 S A M P L E MINIMUM 23 866 S A M P L E MAXIMUM 4 9 . . 6 4 5 MODE V A L U E 35 413 O U A N T I L E S - S 3 4 5 6 7 * S 31 612 MODE FROM NORMAL F I T 35 . 0 2 9 STANDARD D E V . NORMAL F I T 5. . 113 MAXIMUM P E A K P R E S S U R E , MEASURED IN BAR S A M P L E A V E R A G E 3 4 . 9 9 4 STANDARD D E V I A T I O N 3 . 8 7 9 S A M P L E MINIMUM 2 4 . 9 2 0 S A M P L E MAXIMUM 4 5 . 8 S 9 MODE V A L U E 3 6 . 4 8 G O U A N T I L E S - S 3 4 5 6 7 +S 3 0 . 8 4 6 MODE FROM NORMAL F I T 3 4 . 4 9 5 STANDARD D E V . NORMAL F I T 5 . 0 0 6 3 2 . 7 9 0 3 3 . 8 5 8 < 3 4 . 8 9 2 > 3 6 . 3 0 1 3 6 . 8 9 5 3 9 . 1 3 0 < 3 5 . 5 8 3 > 3 6 . 5 9 2 3 7 . 8 1 7 3 9 . 9 2 2 MOMENT OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN O E G R E E S CRANKSHAFT A F T E R I G N I T I O N SAMPLE A V E R A G E 4 7 , 592 STANDARD D E V I A T I O N 6 897 SAMPLE MINIMUM 30 . 9 4 9 SAMPLE MAXIMUM 70 . 2 6 0 MOOE V A L U E 46 9 1 9 O U A N T I L E S - S 3 4 S 6 7 * S 40 9 2 9 MODE FROM NORMAL F I T 45 .691 STANOARD D E V . NORMAL F I T 7 8 0 3 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 . 5 2 4 STANDARD O E V I A T I O N 0 . 0 2 O S A M P L E MINIMUM 0 . 4 6 7 S A M P L E MAXIMUM 0 . 5 7 9 MOOE V A L U E 0 . 5 1 5 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 5 0 3 MODE FROM NORMAL ' F I T 0 . 5 2 2 STANDARO D E V . NORMAL F I T 0 . 0 2 3 0 . 5 1 3 0 . 5 1 7 < 0 . 5 2 4 > 0 . 5 2 9 0 . 5 3 4 0 . 5 4 7 WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) MOMENT OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN O E G R E E S CRANKSHAFT A F T E R I G N I T I O N 5 7 . 1 9 8 > 5 9 . 6 7 5 6 2 . 3 7 7 6 7 . 6 5 5 MOMENT OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TDC SAMPLE A V E R A G E 58 . 3 8 0 STANDARD D E V I A T I O N 8 . 0 5 0 S A M P L E MINIMUM 4 0 809 SAMPLE MAXIMUM 9 0 . 0 2 3 MODE V A L U E 53 . 6 2 5 O U A N T I L E S - 5 3 4 5 6 7 » S 50 8 3 8 MODE FROM NORMAL F I T 56 .284 STANOARD D E V . NORMAL F I T 7 . 363 S A M P L E A V E R A G E STANOARD O E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 S MODE FROM NORMAL F I T STANOARD D E V . NORMAL . 7 8 6 . 112 . 2 0 7 . 9 8 0 . 8 4 3 . 6 9 2 . 8 1 8 . 133 7 . 7 5 0 7 . 7 7 9 < 7 . 8 0 9 > 7 . 8 3 8 7 . 8 6 4 7 . 9 1 4 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 B E 2 IN D E G R E E S C R A N K S H A F T S A M P L E A V E R A G E STANDARO D E V I A T I O N SAMPLE MINIMUM SAMPLE MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T STANDARD D E V . NORMAL 1 6 . 8 9 7 2 . 7 9 0 8 . 3 9 7 2 7 . 6 1 7 1 7 . 4 0 6 + S 1 4 . 2 B 6 1 5 . 3 6 2 1 6 . 2 2 6 S A M P L E A V E R A G E 12 . 0 0 3 STANDARD D E V I A T I O N 5 .822 S A M P L E MINIMUM - 0 . 527 S A M P L E MAXIMUM 34 . 7 4 5 MOOE V A L U E 10 128 O U A N T I L E S - S 3 4 3 6 7 * S 6 4 3 0 MODE FROM NORMAL F1 IT 10 . 4 6 5 STANDARD D E V . NORMAL F I T 5 .671 8 . 7 8 6 9 . 9 5 7 < 1 1 . 3 1 8 > 1 2 . 8 2 9 1 4 . 0 3 7 1 7 . 4 1 2 < 1 7 . 0 9 7 > 1 7 . 4 8 1 1 8 . 3 1 3 19 658 FLAME T R A V E L B E T W E E N P R 0 B E 2 8 P R O B E S IN O E G R E E S C R A N K S H A F T 1 6 . 5 3 9 S A M P L E A V E R A G E 10 788 3 . 4 4 0 STANDARD D E V I A T I O N 7 . 7 3 5 S A M P L E MINIMUM 12 0 3 8 S A M P L E MAXIMUM 37 0 5 6 MODE V A L U E 5 8 6 0 O U A N T I L E S - S 3 4 5 6 7 * S 3 . 339 MODE FROM NORMAL F I T 9 . 567 STANDARO D E V . NORMAL F I T 10 . 0 7 6 5 . 7 8 5 8 . 1 4 6 < 1 0 . 2 1 4 > 1 2 . 3 7 6 1 4 . 4 5 6 1 8 . 1 3 7 Experiment Ml.L P35 o 3 0 0 0 . 0 RPM 1 0 O 0 % OF MAXIMUM METHANE ENGINE S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O 1.1 SPARK ADVANCE 4 0 . 0 DEGR BTDC SPARK P L U G : STANDARD P L U G 35 MOMENT OF F L A M E A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N . 1 8 2 < 3 8 . 0 9 5 > 3 9 . 7 2 5 4 0 . 8 1 5 4 3 . 6 1 2 MOMENT OF F L A M E A R R I V A L AT ION PROBE 2 MEASUREO IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR S A M P L E A V E R A G E 39 . 198 STANDARD D E V I A T I O N 6 591 SAMPLE MINIMUM 25 094 S A M P L E MAXIMUM 73 240 MODE V A L U E 37 .632 O U A N T I L E S - S 3 4 5 6 7 * S 33 595 MODE FROM NORMAL F I T 38 . 0 7 3 STANDARD D E V . NORMAL F I T 4 868 S A M P L E A V E R A G E S T A N D A R D D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T 3 3 . 5 7 8 3 . 9 0 9 2 3 . 1 2 9 4 4 . 4 6 3 3 2 . 6 8 5 +S 2 9 . 7 4 8 3 1 . 4 0 8 3 2 . 3 4 7 3 3 . 6 3 0 < 3 3 . 2 6 9 > 3 4 . 3 5 6 3 5 . 7 6 7 3 7 . 6 5 9 S T A N D A R D D E V . NORMAL F I T 5 . 2 5 5 WORK DONE D U R I N G I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 55 . 784 STANDARD D E V I A T I O N 11 . 3 0 2 S A M P L E MINIMUM 32 . 429 S A M P L E MAXIMUM 94 . 366 MODE V A L U E 51 . 139 O U A N T I L E S - S 3 4 5 6 7 +S 44 . 5 9 4 MODE FROM NORMAL F I T 51 . 496 STANDARO D E V . NORMAL F I T 11 . 8 6 0 S A M P L E A V E R A G E 0 . 4 4 3 S T A N D A R D D E V I A T I O N 0 018 S A M P L E MINIMUM 0 . 3 8 5 S A M P L E MAXIMUM 0 .494 MODE V A L U E 0 . 4 4 5 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 424 MODE FROM NORMAL F I T 0 . 444 S T A N D A R D D E V . NORMAL F I T 0 .02 1 0 . 4 3 3 0 . 4 3 9 < 0 . 4 4 4 > 0 . 4 4 8 0 . 4 5 3 0 . 4 6 1 < 5 3 . 8 3 6 > 5 7 . 4 7 6 6 0 . 4 5 0 6 8 . 8 1 7 MOMENT OF F L A M E A R R I V A L AT ION PROBE 3 MEASUREO IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E O IN BAR ( M E P ) S A M P L E A V E R A G E S T A N D A R D D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 6 3 . 6 4 3 10 451 41 . 9 2 7 1 0 6 . 0 2 1 6 3 . 9 5 9 5 4 . 0 8 5 5 8 . 2 5 5 6 0 . 4 0 0 S A M P L E A V E R A G E 7, 372 S T A N D A R D D E V I A T I O N 0 . 150 S A M P L E MINIMUM 6 .631 S A M P L E MAXIMUM 7 618 MODE V A L U E 7 .464 O U A N T I L E S - S 3 4 5 6 7 » S 7 , .251 MODE FROM NORMAL F I T 7 , 438 STANDARD O E V . NORMAL F I T 0 . 109 7 . 3 4 3 7 . 3 7 9 < 7 . 4 1 4 > 7 . 4 4 9 7 . 4 6 9 7 . 5 1 3 < 6 3 . 5 7 9 > 6 6 . 0 3 9 6 8 . 5 6 8 7 7 . 2 7 3 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 8 E 2 IN D E G R E E S C R A N K S H A F T MODE FROM NORMAL F I T 6 0 . 224 S A M P L E A V E R A G E 16 585 STANDARD D E V . NORMAL F I T 11 . 7 2 5 STANDARD D E V I A T I O N 11 283 S A M P L E MINIMUM -21 . 746 S A M P L E MAXIMUM 54 . 7 7 5 OF MAXIMUM PEAK P R E S S U R E , MEASURED IN D E G R E E S C R A N K S H A F T A F T E R TDC MODE V A L U E 12 . 5 2 9 O U A N T I L E S - S 3 4 5 6 7 * S 7 0 2 5 S A M P L E A V E R A G E 1 8 . 2 2 6 MODE FROM NORMAL F I T 14 6 1 4 S T A N D A R D D E V I A T I O N 2 . 6 2 0 S T A N D A R D D E V . NORMAL F I T 10 2 7 0 S A M P L E MINIMUM 9 . 3 7 2 S A M P L E MAXIMUM 26 6 0 0 MODE V A L U E 1 8 . 5 2 5 F L A M E T R A V E L B E T W E E N P R 0 B E 2 I . P R 0 B E 3 IN I O U A N T I L E S - S 3 4 5 6 7 * S 1 5 . 5 5 0 16 f 124 1 7 . 5 8 3 < 1 8 . 3 7 5 > 1 8 . B 3 6 1 9 . 5 8 7 2 0 . 8 9 1 MODE FROM NORMAL F I T 1 8 . 4 4 0 S A M P L E A V E R A G E 7 , 8 6 0 STANDARD O E V . NORMAL F I T 3 . 0 1 1 S T A N D A R D D E V I A T I O N 12 702 S A M P L E MINIMUM - 3 2 432 S A M P L E MAXIMUM 52 B26 MODE V A L U E 11 . 0 8 5 O U A N T I L E S - S 3 4 5 6 7 + 5 - 4 75B MODE FROM NORMAL F I T 9 . 4 0 9 STANDARD D E V . NORMAL F I T 11 .B21 1 0 . 6 2 4 1 3 . 2 0 7 < 1 5 . 6 7 9 > 1 7 . 9 9 3 2 1 . 5 7 0 2 7 . 8 7 6 1 .654 5 . 3 2 6 < 8 . 2 6 0 > 1 0 . 8 8 5 1 3 . 8 9 3 1 9 . 3 9 3 E x p e r i m e n t M l . M P35 METHANE E N G I N E S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 3 0 0 0 . 0 RPM l O O . O % OF MAXIMUM 1 . 2 4 5 . 0 DEGR BTDC SPARK P L U G : STANDARO P L U G 35 MOMENT OF F L A M E A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 42 . 3 3 6 STANOARD D E V I A T I O N 6 . 3 1 3 SAMPLE MINIMUM 23 .941 S A M P L E MAXIMUM 64 . 2 2 2 MODE V A L U E 39 4 6 6 O U A N T I L E S - S 3 4 5 6 7 * S 36 . 5 9 9 3 9 . 0 2 9 4 0 203 < 4 1 . 6 3 6 > 4 3 . 3 5 8 4 4 . 9 8 6 4 8 . 5 4 1 MODE FROM NORMAL F I T 41 .051 STANDARO D E V . NORMAL F I T 6 . 0 8 0 OF F L A M E A R R I V A L AT ION PROBE 2 MEASURED IN O E G R E E S C R A N K S H A F T A F T E R I G N I T I O N SAMPLE A V E R A G E 6 0 .821 STANOARD D E V I A T I O N 13 463 SAMPLE MINIMUM 6 . 5 4 8 S A M P L E MAXIMUM 101 . 5 1 3 MODE V A L U E 51 . 0 6 3 O U A N T I L E S - S 3 4 5 6 7 * S 49 . 0 0 5 5 2 . 2 9 5 5 5 . 8 9 8 < 6 0 . 1 7 1 > 6 3 . 1 7 8 6 8 . 1 4 5 7 9 . 7 8 8 MODE FROM NORMAL F I T 54 546 STANDARD D E V . NORMAL F I T 11 . 156 OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N S A M P L E A V E R A G E 68 6 4 9 STANDARO D E V I A T I O N 10 6 2 0 SAMPLE MINIMUM 41 334 SAMPLE MAXIMUM 99 486 MODE V A L U E 66 170 O U A N T I L E S - S 3 4 5 6 7 * S 5 7 . 9 0 5 6 2 . 4 1 2 6 5 0 3 9 < 6 7 . 8 2 9 > 7 0 . 3 3 4 73 352 7 8 . 6 4 5 MODE FROM NORMAL F I T 66 266 STANDARD D E V . NORMAL F I T 13. 476 OF MAXIMUM P E A K P R E S S U R E . MEASURED IN O E G R E E S C R A N K S H A F T A F T E R TDC SAMPLE A V E R A G E 14. 228 STANDARD D E V I A T I O N 2. 558 S A M P L E MINIMUM 3 197 S A M P L E MAXIMUM 2 1 . 130 MODE V A L U E 13 471 O U A N T I L E S - S 3 4 5 6 7 * S 11 9 5 3 1 3 . 0 2 7 13 594 < 1 4 . 2 1 7 > 1 4 . 9 2 7 1 5 . 5 2 4 1 6 . 8 6 8 MODE FROM NORMAL F I T 14 285 STANDARD D E V . NORMAL F I T 2 456 MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR S A M P L E A V E R A G E STANDARO O E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 ' ! MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T 3 3 . 6 1 1 3 . 9 3 7 24 . 0 8 9 4 5 . 1 7 6 3 3 . 9 7 3 2 9 . 5 9 4 3 1 . 2 0 0 3 2 . 3 9 6 3 2 . 8 9 6 4 . 6 3 6 3 3 . 5 5 7 > 3 4 . 4 5 5 3 5 . 3 1 1 3 7 . 6 2 8 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 437 STANDARD D E V I A T I O N 0 . 0 1 7 S A M P L E MINIMUM 0 . 3 8 0 S A M P L E MAXIMUM 0 . 4 8 5 MODE V A L U E 0 . 4 3 6 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 4 1 9 MODE FROM NORMAL F I T 0 . 4 3 9 STANDARD D E V . NORMAL F I T 0 . 0 1 7 O 429 O 4 3 3 < 0 437> 0 . 4 4 1 0 . 4 4 8 0 . 4 5 6 WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N STROKE . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 6 652 STANDARD O E V I A T I O N O 288 S A M P L E MINIMUM 3 . 8 0 2 S A M P L E MAXIMUM 7 , 113 MODE V A L U E 6 941 O U A N T I L E S - S 3 4 S 6 7 * S 6 752 MODE FROM NORMAL F I T 6 9 1 8 STANDARD D E V . NORMAL F I T 0 . 136 6 . 8 3 8 6 . 8 7 8 < 6 . 9 0 8 > 6 . 9 3 3 6 . 9 5 4 7 . 0 0 1 FLAME T R A V E L B E T W E E N PROBE 1 8 PROBE2 IN O E G R E E S C R A N K S H A F T S A M P L E A V E R A G E 18 . 484 STANOARD D E V I A T I O N 13 864 S A M P L E MINIMUM •39 2 2 5 S A M P L E MAXIMUM 57 . 6 2 6 MODE V A L U E 10 2 1 0 O U A N T I L E S - S 3 4 5 6 7 * S 7 . 175 MODE FROM NORMAL F I T 13 748 STANDARD O E V . NORMAL F I T 10 . 9 7 5 1 3 . 3 1 3 < 1 G . 1 2 7 > 2 0 . 3 6 6 2 4 . 7 9 1 3 2 . 1 5 3 Experiment Ml.N P 3 5 METHANE E N G I N E S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 3 0 O 0 . 0 RPM 1 0 0 . 0 % OF MAXIMUM 1 . 3 4 5 . 0 DEGR BTDC MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR SPARK P L U G : STANDARD P L U G 35 MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 4 4 . 9 0 5 6 . 6 6 0 2 5 . 4 6 6 6 0 . 8 1 0 4 4 . 2 4 3 -S 3 8 . 5 4 7 4 2 . 1 4 2 4 3 . 8 8 6 < 4 5 . 2 4 4 > 4 6 . 9 7 8 4 8 . 5 5 5 5 4 . 0 5 6 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 MODE FROM NORMAL F I 2 B . 3 2 2 3 . 5 9 6 2 0 . 7 4 7 3 9 . 9 9 8 2 4 . 5 5 7 * S 2 4 . 5 6 0 2 5 . 8 8 5 2 6 . B 6 1 2 6 . 5 9 6 < 2 7 B 8 3 > 2 8 . 6 7 0 2 9 . 9 7 5 3 1 . 9 6 4 STANDARD D E V . NORMAL F I T 4 . 3 4 8 WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) MODE FROM NORMAL F I T 45 162 S A M P L E A V E R A G E 0 . 4 3 7 STANDARD D E V . NORMAL F I T 5 . 2 0 0 STANDARD D E V I A T I O N 0 . 0 1 5 S A M P L E MINIMUM 0 . 389 S A M P L E MAXIMUM 0 . 5 0 1 OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MODE V A L U E 0 . 4 3 9 O U A N T I L E S - S 3 4 5 6 7 +S 0 . 4 2 0 S A M P L E A V E R A G E 70 563 MODE FROM NORMAL F I T 0 . 4 3 6 STANDARD D E V I A T I O N 18 627 S T A N D A R D D E V . NORMAL F I T 0 . 0 2 5 S A M P L E MINIMUM 1 449 S A M P L E MAXIMUM 122 532 MODE V A L U E 6 0 729 WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N ST O U A N T I L E S - S 3 4 5 6 7 * S 54 579 6 0 . 6 6 1 65 . 0 8 3 < 6 9 . 4 6 3 > 7 4 . 0 5 6 7 9 . 3 2 6 9 0 . 6 4 7 MODE FROM NORMAL F I T 66 .542 S A M P L E A V E R A G E 6 . 0 9 8 STANDARD D E V . NORMAL F] IT 18 .971 S T A N D A R D D E V I A T I O N 0 . 7 9 7 S A M P L E MINIMUM 3 . 2 5 5 S A M P L E MAXIMUM 6 . 7 0 2 OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N MODE V A L U E 6 . 4 5 1 O U A N T I L E S - S 3 4 5 6 7 » S 5 . 9 3 0 S A M P L E A V E R A G E 81 7 2 0 MODE FROM NORMAL F I T 6 . 4 4 1 STANDARD D E V I A T I O N 13 6 6 0 STANDARD D E V . NORMAL F I T 0 . 254 S A M P L E MINIMUM 4 5 . 7 4 0 S A M P L E MAXIMUM 126. 5 3 0 MODE V A L U E 93 . 709 O U A N T I L E S - S 3 4 5 6 7 * S 66 44 1 7 4 . 0 7 0 7 7 . . 396 < 8 0 . 9 0 2 > 8 7 . 1 1 8 8 9 . 7 3 7 9 4 . 9 9 8 MODE FROM NORMAL F I T 8 4 . 777 STANDARD O E V . NORMAL F I T 19. 756 0 . 4 2 B 0 . 4 3 2 < 0 . 4 3 7 > 0 . 4 4 1 0 . 4 4 7 0 . 4 5 3 6 . 1 6 2 6 . 2 6 3 < 6 . 3 7 B > 6 . 4 2 8 6 . 4 9 8 6 . 5 6 8 MOMENT OF MAXIMUM P E A K P R E 5 5 U R E . MEASURED IN D E G R E E S C R A N K S H A F T A F T E R TOC S A M P L E A V E R A G E 1 4 . 5 6 5 STANDARD D E V I A T I O N 8 . 7 3 1 S A M P L E MINIMUM 0 . 2 7 6 S A M P L E MAXIMUM 1 2 6 . 6 B 6 MODE V A L U E 1 4 . 7 6 0 O U A N T I L E S - S 3 4 5 6 7 * S 1 1 . 5 1 9 1 3 . 3 2 9 1 3 . 9 6 5 < 1 4 . 6 7 3 > 1 5 . 1 4 7 1 5 . 7 4 8 1 7 . 0 3 6 MODE FROM NORMAL F I T 1 4 . 7 5 4 STANDARD D E V . NORMAL F I T 3 . 2 7 8 Experiment M1.0 P35 o CO METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 3000.0 RPM I0O.0 X OF MAXIMUM 0.9 35.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE I MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 36.026 5.551 23.B39 68.009 „„„ f c 34.421 OUANTILES -S 3 4 5 6 7 »S 31.498 33.029 34.508 < 35.469> 36.761 38.072 40.927 MOOE FROM NORMAL FIT 34.802 STANDARO DEV. NORMAL FIT 4.702 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE 52.326 11.790 31 .668 92.059 45.035 OUANTILES -S 3 4 5 6 7 *S 41.154 44.771 46.987 < 49.423> 53.188 56.688 64.858 MOOE FROM NORMAL FIT 45 806 STANDARD OEV. NORMAL FIT 5.759 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 60.445 9.227 37.902 89.181 _ 58.734 OUANTILES -S 3 4 5 6 7 *S 51.073 54.875 57.976 < 59.415> 61.994 64.792 70.096 MODE FROM NORMAL FIT 57.770 STANDARD DEV. NORMAL FIT 8.823 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE 11.730 4.004 0. 708 23.809 1 I .055 OUANTILES -S 3 4 5 6 7 *S 7.561 9.556 10.651 < 11.659> 12.736 13.988 15.871 MODE FROM NORMAL FIT 11.882 STANDARD DEV. NORMAL FIT 4.756 MAXIMUM PEAK PRESSURE. MEASUREO IN BAR SAMPLE AVERAGE STANDARD OEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE 28.B98 3.804 20.145 4 1 .856 28.513 OUANTILES -S 3 4 5 6 7 *S 25.232 26.662 27.706 < 28.585> 29.580 30.646 32.613 MODE FROM NORMAL FIT 78.323 STANDARD DEV. NORMAL FIT 4.173 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASUREO IN BAR (MEP) SAMPLE AVERAGE ~ STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 *S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 0.556 0.017 O 510 0.604 0.550 0.54O 0.547 0.551 < 0 556> 0 561 0.567 0.573 0.557 0.025 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) 7.672 0. 188 6.963 7.977 OUANTILEs'-S 3 4 5 6 7 *S 7^12 7.617 7.662 < 7.709> 7.750 7.790 7.864 MODE FROM NORMAL FIT 7.730 STANDARD DEV. NORMAL rIT 0.182 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE FLAME TRAVEL BETWEEN PROBE 1 » PROBE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 16.300 STANDARD DEVIATION 11.138 SAMPLE MINIMUM -26.24 1 SAMPLE MAXIMUM 53.481 MODE VALUE 11. 129 OUANTILES -S 3 4 S 6 7 *S 6.588 MODE FROM NORMAL FIT 12.128 STANDARD DEV. NORMAL FIT 9.164 .829 11.756 < 14.308> 17.249 20.126 26.643 FLAME TRAVEL BETWEEN PROBE2 8 PROBE3 IN DEGREES CRANKSHAFT SAMPLE AVERAGE STANOARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE 8. 1 IB 11.370 -23.821 32.082 10.536 OUANTILES -S 3 4 5 6 7 *S H.l" 3.366 6.559 < 9.271> ,1.655 ,4.907 ,9.0-6 MODE FROM NORMAL FIT ,,.455 STANDARD DEV. NORMAL FIT ,,.187 Experiment Ml.P P35 METHANE ENGINE SPEED AIP FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 1BOO.0 RPM 100.0 % OF MAXIMUM 35.0 DEGR BTDC MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 34 .074 STANDARD DEVIATION 5 . 129 SAMPLE MINIMUM 27 .485 SAMPLE MAXIMUM 4 1 .587 MODE VALUE 32 .332 OUANTILES -S 3 4 5 6 7 »S 0 .0 MODE FROM NORMAL FIT 33 . 766 STANDARD DEV. NORMAL FIT 4 .019 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 »S MODE FROM NORMAL FIT STANDARD OEV. NORMAL FIT 42.735 5.051 29.521 50.461 46.753 36.948 40.182 42.115 45.848 4 . 168 < 43.533> 45.029 46.314 47.873 27.485 27.485 < 32.419> 32.419 33.349 35.531 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 5TANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 36.487 6.913 24.281 70.761 33.480 30.107 32.289 33.349 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.677 STANDARD 0EVIAT10N 0.022 SAMPLE MINIMUM 0.617 SAMPLE MAXIMUM 0.731 MODE VALUE 0.680 OUANTILES -S 3 4 5 6 7 *5 0.655 MODE FROM NORMAL FIT 0.676 STANDARD OEV. NORMAL FIT 0.021 0 666 0.671 < 0.677> 0.682 0.689 0.701 < 34.743> 37.025 39.125 44.478 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) MODE FROM NORMAL FIT 32 575 SAMPLE AVERAGE 7 .957 STANDARD OEV. NORMAL FIT 3 934 STANDARD DEVIATION 0 . 193 SAMPLE MINIMUM 6 .605 SAMPLE MAXIMUM 8 222 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 8 .07 1 OUANTILES -S 3 4 5 6 7 *S 7 .751 SAMPLE AVERAGE 44 .782 MODE FROM NORMAL FIT 8 .078 STANDARD DEVIATION 6 696 STANDARD OEV. NORMAL FIT 0 103 SAMPLE MINIMUM 31 .098 SAMPLE MAXIMUM 68 774 MODE VALUE 40 .909 FLAME TRAVEL BETWEEN PR0BE2 8 > PROBE3 IN 1 OUANTILES -S 3 4 5 6 7 »S 38 .147 40.622 41.883 < 44.626> 46.611 47.964 51.878 MODE FROM NORMAL FIT 42 832 SAMPLE AVERAGE 8 295 STANDARD DEV. NORMAL FIT 8 510 STANDARD DEVIATION 5. .311 SAMPLE MINIMUM - 18 971 SAMPLE MAXIMUM 19. 987 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE 6. 595 OUANTILES -S 3 4 5 6 7 +S 3 562 SAMPLE AVERAGE 14 .215 MODE FROM NORMAL FIT 7 336 STANDARD DEVIATION 3 804 STANDARD DEV. NORMAL FIT 3 335 SAMPLE MINIMUM 5 .267 SAMPLE MAXIMUM 25 591 MODE VALUE 13 .524 OUANTILES -S 3 4 5 6 7 'S 10 .294 12.087 12.990 < 13.859> 15.271 16.462 18.204 MODE FROM NORMAL FIT 14 . 169 STANDARO DEV. NORMAL FIT 5 . 131 7.887 7.963 < 8.018> 8.062 8.083 8.128 6.048 6.828 < 7.901> 9.229 10.805 13.510 Experiment Ml.Q P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 2500.0 RPM 10O.0 % OF MAXIMUM 1 .0 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK ADVANCE 25.0 DEGR 1 JTOC SAMPLE AVERAGE 30.549 SPARK PLUG: STANDARD PLUG 35 STANDARD DEVIATION 4.691 SAMPLE MINIMUM 19.991 SAMPLE MAXIMUM 55.587 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 30.002 OUANTILES -S 3 4 5 6 7 +S 25.833 27.933 29.238 30. 301 > 31 SAMPLE AVERAGE 31 . 130 MODE FROM NORMAL FIT 30.067 STANDARD DEVIATION 12 .652 STANDARD DEV. NORMAL FIT 5.223 SAMPLE MINIMUM 10 . 1 17 SAMPLE MAXIMUM 73 .667 MODE VALUE 26 .666 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEPI OUANTILES -S 3 4 5 6 7 «S 23 .261 25.024 26 .051 < 27.214> 28.253 29.778 38.335 MODE FROM NORMAL FIT 26 .552 SAMPLE AVERAGE 0.617 STANDARD DEV. NORMAL FIT 3 800 STANDARD DEVIATION 0.020 SAMPLE MINIMUM 0.562 SAMPLE MAXIMUM 0.676 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 0.615 OUANTILES -S 3 4 5 6 7 *S 0.596 0.606 0.612 < 0.617> 0 SAMPLE AVERAGE 42. 021 MODE FROM NORMAL FIT 0 618 STANDARD DEVIATION 9 235 STANDARD DEV. NORMAL FIT 0.022 SAMPLE MINIMUM 18 412 SAMPLE MAXIMUM 80 550 MODE VALUE 38 478 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 6 7 »S 33. 433 36.643 38. 730 < 40.564> 42.532 45.538 50.968 MODE FROM NORMAL FIT 39. 622 SAMPLE AVERAGE 8.921 STANDARD DEV. NORMAL FIT 6 902 STANDARD DEVIATION 0.881 SAMPLE MINIMUM 5.955 SAMPLE MAXIMUM 9.554 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 9.216 OUANTILES -S 3 4 5 6 7 +S 8.708 8.940 9.046 < 9.116> 9 SAMPLE AVERAGE 50. 140 MODE FROM NORMAL FIT 9. 191 STANDARO DEVIATION 8. 950 STANDARD DEV. NORMAL FIT 0.270 484 32.726 35.052 622 0.628 0.638 .185 9.247 9.327 SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 26.142 79.04 1 52 040 »S 41.376 45.412 47.585 FLAME TRAVEL BETWEEN PROBE 1 » PR0BE2 IN DEGREES CRANKSHAFT < 50.240> 52.002 54.360 58.185 MODE FROM NORMAL FIT 50.266 SAMPLE AVERAGE 10 890 STANDARD DEV. NORMAL FIT 8.768 STANDARD DEVIATION 12 743 SAMPLE MINIMUM -38 009 SAMPLE MAXIMUM 50 896 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE 11. 074 OUANTILES -S 3 4 5 6 7 »S 2. 556 SAMPLE AVERAGE 23.480 MOOE FROM NORMAL FIT 11 . 770 STANDARD 0EVIAT10N 4.453 STANDARD DEV. NORMAL FIT 6. 250 SAMPLE MINIMUM 9.292 SAMPLE MAXIMUM 39.402 MODE VALUE 36.543 FLAME TRAVEL BETWEEN PR0BE2 « . PR0BE3 IN 1 OUANTILES -S 3 4 5 6 7 +S 20.345 21.767 22.641 < 24.397> 25.300 26.267 27.453 MOOE FROM NORMAL FIT 24.513 SAMPLE AVERAGE 8 119 STANDARO DEV. NORMAL FIT 5. 304 STANDARD DEVIATION 8 .357 SAMPLE MINIMUM - 19 903 SAMPLE MAXIMUM 39 508 MODE VALUE 9 184 OUANTILES -S 3 4 5 6 7 *S 0 172 MODE FROM NORMAL FIT 8 072 STANDARD DEV. NORMAL FIT 8 .559 8.581 10.457 < 12.155> 13.700 15.770 21.464 DEGREES CRANKSHAFT 3 922 6.IB5 9.909 12.274 15.985 Experiment G2.1 P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 2500.0 RPM 100.0 % OF MAXIMUM 1.0 25.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 32 083 STANDARD DEVIATION 12 636 SAMPLE MINIMUM 11. 813 SAMPLE MAXIMUM 73 683 MOOE VALUE 26 .636 OUANTILES -S 3 4 5 6 7 *S 23 .715 MOOE FROM NORMAL FIT 27 158 STANDARD DEV. NORMAL FIT 4 545 < 27.900> 29.537 30.949 42.914 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 41 384 STANDARD DEVIATION 8 .565 SAMPLE MINIMUM 18 .488 SAMPLE MAXIMUM . 81 202 MODE VALUE 37 .433 OUANTILES -S 3 4 5 6 7 »S 33 .020 MODE FROM NORMAL FIT 39 .727 STANDARD DEV. NORMAL FIT 11 .294 .197 < 40.421> 42.938 45.748 50.304 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 49 569 STANDARD OEVIATION 9 .064 SAMPLE MINIMUM 27 .251 SAMPLE MAXIMUM 116 B52 MOOE VALUE 46 851 OUANTILES -S 3 4 5 6 7 • S 11 361 MODE FROM NORMAL FIT 47 .735 STANDARD DEV. NORMAL F] IT 6 .340 45.228 46.993 < 48.487> 50.597 53.179 58.131 MOMENT OF MAXIMUM PEAK PRESSURE, MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT 23.712 5.991 4.436 119.335 24 . 783 + S 20.391 21 .839 23.261 23.749 24.223> 24.799 25.587 26.805 STANDARD DEV. NORMAL FIT 4.917 MAXIMUM PEAK PRESSURE. MEASUREO IN BAR SAMPLE AVERAGE STANDARO DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE OUANTILES -S 3 4 5 MODE FROM NORMAL FIT 36.742 5.900 17.997 56.497 34.440 +S 31.2O0 33.247 34.486 34.648 35.858> 37.708 39.161 43.094 STANDARD DEV. NORMAL FIT 4.998 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.564 STANDARD DEVIATION 0.020 SAMPLE MINIMUM 0.500 SAMPLE MAXIMUM 0.625 MODE VALUE 0.564 OUANTILES -S 3 4 5 6 7 *S 0.542 MODE FROM NORMAL FIT 0.568 STANDARD DEV. NORMAL FIT 0.026 0.554 0.559 < 0.564> 0.569 0.575 0.585 WORK DONE DURING COMPRESSION/EXPANSION STROKE,MEASURED IN BAR (MEP) SAMPLE AVERAGE 8.792 STANDARD OEVIATION 0.661 SAMPLE MINIMUM 5.1CO SAMPLE MAXIMUM 9.343 MODE VALUE 9.034 OUANTILES -S 3 4 5 6 7 +S 8.672 MODE FROM NORMAL FIT 9.000 STANDARD DEV. NORMAL FIT 0.195 B.833 8.911 8.968> 9.021 9.057 9.123 FLAME TRAVEL BETWEEN PROBE 1 ft PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 9 301 STANDARD DEVIATION 12. 832 SAMPLE MINIMUM -44 . 002 SAMPLE MAXIMUM 33 026 MODE VALUE 9 757 OUANTILES -S 3 4 5 6 7 *S 1 .782 MODE FROM NORMAL FIT 10 .420 STANDARD DEV. NORMAL FIT 5 .654 7.062 9.168 < 10.619> 12.845 15.115 19.827 FLAME TRAVEL BETWEEN PR0EE2 ft PROBE3 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 8 185 STANDARD DEVIATION 8 . 104 SAMPLE MINIMUM -13 482 SAMPLE MAXIMUM 35 .650 MODE VALUE 7 .501 OUANTILES -S 3 4 5 6 7 *S O .062 MODE FROM NORMAL FIT 8 .956 STANDARD DEV. NORMAL FIT 7 .992 4.640 6.527 < .113> 10.137 12.192 15.526 E x p e r i m e n t G2.1 P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE A IP/FUEL RATIO O.f SPARK ADVANCE 30 SPARK PLUG: STANDARD PLUG 35 2500.0 RPM lOO.O % OF MAXIMUM O DEGR BTDC MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 28. 503 STANDARD DEVIATION 6 23 1 SAMPLE MINIMUM 13 .830 SAMPLE MAXIMUM 79 .066 MODE VALUE 28 . 100 OUANTILES -S 3 4 5 6 7 *S 24 861 26.162 27 MODE FROM NORMAL FIT 28 . 174 STANDARD DEV. NORMAL FIT 3 .713 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN SAMPLE AVERAGE 39 .438 STANDARD DEVIATION 7 036 SAMPLE MINIMUM 18 .922 SAMPLE MAXIMUM 75 .485 MODE VALUE 38 .365 OUANTILES -S 3 4 5 6 7 *S 32 776 35.321 36 MODE FROM NORMAL FIT 37 633 STANDARD OEV. NORMAL FIT 5 614 OF FLAME ARRIVAL AT ION PR08E 3 MEASURED IN SAMPLE AVERAGE 46 .989 STANDARD OEVIATION 8 .437 SAMPLE MINIMUM 24 .960 SAMPLE MAXIMUM 82 . 384 MODE VALUE 45 832 OUANTILES -S 3 4 5 6 7 *S 39 .714 42.249 44 MODE FROM NORMAL FIT 45 .096 STANDARD DEV. NORMAL FIT 7 .591 < 2S.149> 28.910 29.860 31.752 38.860> 40.166 42.723 46.583 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT 18.074 3.638 3.072 25.926 19.022 +S 15.128 16.577 18.565 17.578 < 18.408> 19.235 19.893 21.595 STANDARD OEV. NORMAL FIT 3.438 MAXIMUM PEAK PRESSURE. MEASUREO IN BAR SAMPLE AVERAGE 4 1 203 STANDARD DEVIATION 4 297 SAMPLE MINIMUM 30 989 SAMPLE MAXIMUM 52 .035 MODE VALUE 40 855 OUANTILES -S 3 4 5 6 7 *S 36 .481 38.937 39.901 MODE FROM NORMAL FIT 40 801 STANDARD DEV. NORMAL FIT 3 .661 40.925> 42.069 43.305 45.763 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.620 STANDARD DEVIATION 0.018 SAMPLE MINIMUM 0.564 SAMPLE MAXIMUM 0.668 MODE VALUE 0.618 OUANTILES -S 3 4 5 6 7 *S 0.602 MOOE FROM NORMAL FIT 0.618 STANDARD DEV. NORMAL FIT 0.025 0.609 0.615 < 0.619> 0.623 0.630 0.63B WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 9 190 STANDARD DEVIATION 0. 735 SAMPLE MINIMUM 5. 581 SAMPLE MAXIMUM 9 647 MODE VALUE 9. 351 OUANTILES -S 3 4 5 6 7 *S 9 246 MOOE FROM NORMAL FIT 9 352 STANOARD DEV. NORMAL FIT 0. 129 9.299 9.323 < 9.355> 9.381 9.406 9.452 FLAME TRAVEL BETWEEN PROBE 1 & PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 10 935 STANDARD DEVIATION 7 809 SAMPLE MINIMUM -44 844 SAMPLE MAXIMUM 44 .912 • MODE VALUE a .448 OUANTILES -S 3 4 5 6 7 »S 5 .559 7 MODE FROM NORMAL FIT 9 . 198 STANDARD DEV. NORMAL FIT 6 345 .428 8.664 < 10.491> 11.796 13.848 17.813 FLAME TRAVEL BETWEEN PROBE2 ft PROBES IN DEGREES CRANKSHAFT SAMPLE AVERAGE 7. 550 STANOARD DEVIATION 8 968 SAMPLE MINIMUM -19. .893 SAMPLE MAXIMUM 51 . 593 MODE VALUE 6 . 170 OUANTILES -S 3 4 5 6 7 +S -0 . 105 MOOE FROM NORMAL FIT 7 , .082 STANDARD DEV. NORMAL FIT 9 . 431 3.147 4.753 8.559 10.575 13.821 Experiment G2.2 P35 2470.O RPM lOO.O % OF MAXIMUM GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 1 1 SPARK ADVANCE 30.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 42 879 STANDARD DEVIATION 10 808 SAMPLE MINIMUM 24 498 SAMPLE MAXIMUM 68 .609 MOOE VALUE 35 066 OUANTILES -S 3 4 5 6 7 *S 32 646 35. 351 36 MODE FROM NORMAL FIT 35 .614 STANDARD DEV. NORMAL F] [T 4 .273 OF FLAME ARRIVAL AT ION PR08E 2 MEASURED IN SAMPLE AVERAGE 46 095 STANDARD DEVIATION 7 . 145 SAMPLE MINIMUM 29 .131 SAMPLE MAXIMUM 67 .045 MODE VALUE 44 .533 OUANTILES -S 3 4 5 6 7 *S 38 .374 42 151 44 MODE FROM NORMAL FIT 46 489 STANDARD DEV. NORMAL FIT 7 .454 OF FLAME ARRIVAL AT ION PROBE 3 MEASUREO IN SAMPLE AVERAGE 60 .599 STANDARD DEVIATION 10 .487 SAMPLE MINIMUM 36 .798 SAMPLE MAXIMUM 105 .497 MOOE VALUE 57 .551 OUANTILES -S 3 4 5 6 7 *S 50 . 389 54 , .774 56 MOOE FROM NORMAL FIT 57 .015 STANDARD DEV. NORMAL FIT 6 .581 39.078> 42.696 49.912 56.260 < 45.659> 47.943 49.804 52.784 < 58.806> 61.358 64.713 72.050 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MOOE FROM NORMAL FIT 31.7 17 6 .478 19. 12 1 54 .505 29.073 +S 25.903 27.810 29.210 29.676 < 30.306> 31.962 33.613 37.807 STANDARD DEV. NORMAL FIT 5.218 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.629 STANDARD DEVIATION 0.019 SAMPLE MINIMUM 0.564 SAMPLE MAXIMUM 0.679 MODE VALUE 0.625 OUANTILES -S 3 4 5 6 7 +S 0.609 MODE FROM NORMAL FIT 0 627 STANDARD DEV. NORMAL FIT 0.022 0.618 0.623 < 0.628> 0.633 0.638 0.648 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 8.379 STANDARD OEVIATION 0.329 SAMPLE MINIMUM 6.929 SAMPLE MAXIMUM 8.930 MOOE VALUE 8.617 OUANTILES -S 3 4 5 6 7 *S 8.045 MOOE FROM NORMAL FIT 8.530 STANDARD OEV. NORMAL FIT 0.334 8.258 8.345 < 8.435> 8.513 8.603 8.696 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE 23.050 STANDARO DEVIATION 3.525 SAMPLE MINIMUM 11.187 SAMPLE MAXIMUM 33.063 MODE VALUE 25.087 OUANTILES -S 3 4 5 6 7 +S 19.556 21.059 21.996 < 23.430> 24.727 25.140 26.466 MODE FROM NORMAL FIT 23.532 STANDARD DEV. NORMAL FIT 4.630 Experiment G2.3 P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 3OOO.0 RPM 10O.0 % OF MAXIMUM 1 .0 30.0 OEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 34 708 STANOARD DEVIATION 7, 338 SAMPLE MINIMUM 30. 120 SAMPLE MAXIMUM 80 324 MODE VALUE 33. 290 OUANTILES -S 3 A 5 6 7 •S 29 771 : MODE EROM NORMAL FIT 33. 259 STANDARD DEV. NORMAL FIT 5 106 OF FLAME ARRIVAL AT ION PROBE 2 ME; SAMPLE AVERAGE 47. 562 STANDARD DEVIATION 8 817 SAMPLE MINIMUM 27. 763 SAMPLE MAXIMUM 85. 984 MODE VALUE 45 351 OUANTILES -S 3 4 5 6 7 »S 38 564 • MODE FROM NORMAL FIT 44. 656 STANOARD DEV. NORMAL FIT 8. 434 OF FLAME ARRIVAL AT ION PROBE 3 ME/ SAMPLE AVERAGE 60 377 STANDARD DEVIATION 9. 849 SAMPLE MINIMUM 32. 292 SAMPLE MAXIMUM 93 076 MODE VALUE 58 213 OUANTILES -S 3 4 5 6 7 *S 51 . 375 ! MOOE FROM NORMAL FIT 56. 473 STANDARD DEV. NORMAL FIT 6. 642 OF MAXIMUM PEAK PRESSURE. MEASUREO SAMPLE AVERAGE 23 604 STANDARD DEVIATION 3. 655 SAMPLE MINIMUM 10 753 SAMPLE MAXIMUM 32. 722 MODE VALUE 22 982 OUANTILES -S 3 4 5 S 7 *S 20 . 184 : MODE FROM NORMAL FIT 23. 607 STANDARD DEV. NORMAL FIT 2 946 < 33.836> 34.825 36.251 38.471 < 46.818> 48.792 51.226 57.O02 < 59.054> 61.613 65.197 70.955 IN DEGREES CRANKSHAFT AFTER TDC 175 22.968 < 23.492> 24.344 25.191 27.412 MAXIMUM PEAK PRESSURE, MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT 29.610 4 . 346 19.504 42.209 29.674 +S 25.278 26.925 28.012 29.156 < 29.437> 30.456 32.084 34.159 STANDARD DEV. NORMAL FIT 6.307 WORK DONE DURING INTAKE/EXHAUST STROKE,MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.580 STANDARD DEVIATION 0.019 SAMPLE MINIMUM 0-533 SAMPLE MAXIMUM 0.635 MODE VALUE 0.583 OUANTILES -S 3 4 5 6 7 *S 0.561 MODE FROM NORMAL FIT 0.578 STANOARD DEV. NORMAL FIT 0.023 0.569 0.576 < 0.581> 0.585 0.590 0.601 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 8.355 STANDARD DEVIATION 0.487 SAMPLE MINIMUM 5.447 SAMPLE MAXIMUM 9.009 MODE VALUE 8.453 OUANTILES -S 3 4 5 6 7 +S 8.(58 MODE FROM NORMAL FIT 8.457 STANDARD DEV. NORMAL FIT 0.221 .305 8.373 < 8.435> 8.501 8 558 8.651 FLAME TRAVEL BETWEEN PROBE 1 » PR0BE2 IN OEGREES CRANKSHAFT SAMPLE AVERAGE 12 .854 STANDARD DEVIATION 8 .963 SAMPLE MINIMUM -30 . 189 SAMPLE MAXIMUM 51 . 353 MODE VALUE 9 .733 OUANTILES -S 3 4 5 6 7 *S 6 .269 MODE FROM NORMAL FIT 1 1 .803 STANDARD DEV. NORMAL FIT 8 . 164 9.049 10.363 < 12.073> 14.176 16.635 20.471 FLAME TRAVEL BETWEEN PR0BE2 8 PROBE3 IN OEGREES CRANKSHAFT SAMPLE AVERAGE 12. 815 STANDARD DEVIATION 9. 771 SAMPLE MINIMUM -30. 338 SAMPLE MAXIMUM 39 503 MODE VALUE 17, 707 OUANTILES -S 3 4 5 6 7 *S 2 875 MODE FROM NORMAL FIT 14 , 580 STANDARD DEV. NORMAL FIT 10 900 7.816 10740 < 13.285> 15.951 17.986 21.670 Experiment G2.4 P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 2500.0 RPM 65.O % OF MAXIMUM 1 .0 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK ADVANCE 30.0 DEGR E JTDC SAMPLE AVERAGE 28 . 295 SPARK PLUG: STANDARD PLUG 35 STANDARD DEVIATION 3 . 385 SAMPLE MINIMUM 18 . 376 SAMPLE MAXIMUM 36 . 246 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 30 . 103 OUANTILES -S 3 4 5 6 7 +S 24 .990 26.326 27.416 < 28.276> 29 SAMPLE AVERAGE 35 112 MODE FROM NORMAL FIT 2S .521 STANDARO DEVIATION 10. 183 STANDARD DEV. NORMAL FIT 4 .481 SAMPLE MINIMUM 15 496 SAMPLE MAXIMUM BO .232 MOOE VALUE 31 006 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) OUANTILES - 5 3 4 5 6 7 *S 28 742 30. 463 31 .591 < 32.686> 33.727 35.599 38.976 MODE FROM NORMAL FIT 31 642 SAMPLE AVERAGE 0 483 STANDARD DEV. NORMAL FIT 4 757 STANDARD DEVIATION 0 .015 SAMPLE MINIMUM 0 450 SAMPLE MAXIMUM 0 .54 1 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 0 .480 OUANTILES -S 3 4 5 6 7 +S 0 .469 0.475 0.480 < 0.483> 0 SAMPLE AVERAGE 43 659 MODE FROM NORMAL FIT 0 481 STANDARO DEVIATION 7. 289 STANDARD DEV. NORMAL FIT 0 .015 SAMPLE MINIMUM 22 880 SAMPLE MAXIMUM 86 630 MODE VALUE 43 466 WORK DONE DURING COMPRESSION/EXPANSION STROKE .MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 6 7 *S 36 .991 39. 777 41 .150 < 42.965> 44.793 46.698 50 395 MODE FROM NORMAL FIT 42 087 SAMPLE AVERAGE 6 280 STANDARD DEV. NORMAL FIT 7 403 STANDARO DEVIATION 0 252 SAMPLE MINIMUM 3 .828 SAMPLE MAXIMUM 6 .667 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 6 223 OUANTILES -S 3 4 5 6 7 +S 6 .104 6.204 6.252 < 6.308> 6 SAMPLE AVERAGE 56 797 MODE FROM NORMAL FIT 6 .306 STANDARD DEVIATION 8. .550 STANDARD OEV. NORMAL FIT 0 .313 SAMPLE MINIMUM 37 .4 13 SAMPLE MAXIMUM 82 . 107 MODE VALUE 55 569 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES CRANKSHAFT OUANTILES -S 3 4 5 6 7 +S 48 633 52. 843 55 .149 < 56.999> 59.647 62.845 69.549 MODE FROM NORMAL FIT 55 525 SAMPLE AVERAGE 8 .547 STANDARD DEV. NORMAL FIT 6 597 STANDARO DEVIATION 10 632 SAMPLE MINIMUM •38 955 SAMPLE MAXIMUM 47 965 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MOOE VALUE 10 843 OUANTILES -S 3 4 5 6 7 *S 3 .143 7.080 8.501 < 10.100> 1 1 SAMPLE AVERAGE 22 276 MODE FROM NORMAL FIT 10 S94 STANDARD DEVIATION 3 483 STANDARD DEV. NORMAL FIT 5 055 487 0.491 0.501 .399 6.481 6.553 1.341 12.537 15.754 SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 7 .665 33.991 22 .748 18.895 20.923 21.690 22 .535 2 .804 < 22.599> 23.040 23.844 25.453 FLAMF TRAVEL BETWEEN PR0BE2 » PROBE3 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 13. 138 STANDARD DEVIATION 9.384 SAMPLE MINIMUM -26.248 SAMPLE MAXIMUM 4 1.870 MODE VALUE 17.035 OUANTILES -S 3 4 5 6 7 +S 4.491 MODE FROM NORMAL FIT 12.626 8.034 10.609 < 12.887> 15.466 17.765 21.897 STANDARD DEV. NORMAL FIT 11.B73 Experiment G2.6 P35 <7\ GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 2500.0 PPM 65.O % OF MAXIMUM 0.9 30.0 DEGR BTDC MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK PLUG: STANDARO PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 30.212> 31.132 32.698 35.086 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 3t .712 STANDARD DEVIATION B . 149 SAMPLE MINIMUM 15 236 SAMPLE MAXIMUM 76 050 MODE VALUE 29 806 OUANTILES -S 3 4 S S 7 +S 26 .938 MODE FROM NORMAL FIT 29 .935 STANDARD DEV. NORMAL FIT 3 . 1B6 SAMPLE AVERAGE STANDARO DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT STANDARO DEV. NORMAL 30.662 3.359 17.257 37.820 32.465 +S 27.292 2B.785 29.971 31.206 IT 4.874 < 31.048> 31.931 32.669 34.129 SAMPLE AVERAGE 39. 324 STANDARD DEVIATION 6. .676 SAMPLE MINIMUM 19 502 SAMPLE MAXIMUM 77 927 MODE VALUE 35 934 OUANTILES -S 3 4 5 6 7 »S 33 107 MODE FROM NORMAL FIT 38 172 STANDARD DEV. NORMAL FIT 6 .855 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASUREO IN BAR (MEP) SAMPLE AVERAGE 0.548 STANDARD DEVIATION 0.015 SAMPLE MINIMUM 0.503 SAMPLE MAXIMUM 0.591 MODE VALUE 0.548 OUANTILES -S 3 4 5 6 7 +S 0.533 MODE FROM NORMAL FIT 0.548 STANDARD OEV. NORMAL FIT 0.017 0.540 0.545 < 0.548> 0.552 0.557 0.564 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 52.128> 54.308 56.738 61.946 MOMENT OF MAXIMUM PEAK PRESSURE. MEASUREO IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE 53 450 STANDARD DEVIATION 9 584 SAMPLE MINIMUM 29 676 SAMPLE MAXIMUM 83 .249 MODE VALUE 51 .440 OUANTILES -S 3 4 5 6 7 *S 44 .386 MODE FROM NORMAL FIT 51 .625 STANDARD DEV. NORMAL FIT 7 .872 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 6.340 STANDARD DEVIATION 0.461 SAMPLE MINIMUM 3.815 SAMPLE MAXIMUM 6.748 MODE VALUE 6.351 OUANTILES -S 3 4 5 6 7 +S 6.245 MODE FROM NORMAL FIT 6.382 STANDARO OEV. NORMAL FIT 0.266 6.307 6.339 < 6.372> 6.448 6.565 6.633 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 19.871 3.804 6.554 30.430 19.735 16.628 18.016 19.057 FLAME TRAVEL BETWEEN PROBE 1 ft PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 7.612 STANDARD DEVIATION 8.091 SAMPLE MINIMUM -44.880 SAMPLE MAXIMUM 28.936 MODE VALUE 8.175 OUANTILES -S 3 4 5 6 7 +S 3.293 MODE FROM NORMAL FIT 8.270 STANDARD DEV. NORMAL FIT 6.398 5.661 6.916 < 8190> 9.596 11.131 13.133 < 20006> 21.189 22.132 23.473 FLAME TRAVEL BETWEEN PR0BE2 ft PROBES IN DEGREES CRANKSHAFT 246 SAMPLE AVERAGE 14 . 126 148 STANDARD DEVIATION 8 .934 SAMPLE MINIMUM -24 . 448 SAMPLE MAXIMUM 47 .032 MODE VALUE 13 .526 OUANTILES -S 3 4 5 6 7 *S 6 .313 MODE FROM NORMAL FIT 12 . B77 STANDARO DEV. NORMAL FIT 6 .885 9.704 11.798 < 13.399> 15.095 17.416 21.961 E x p e r i m e n t G 2 . 7 P35 GASOLINE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 2432.0 RPM 65.0 % OF MAXIMUM 1 . 1 30.0 OEGR BTDC MAXIMUM PEAK PRESSURE. MEASURED IN BAR SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 43 .734 STANDARD DEVIATION 9 .367 SAMPLE MINIMUM 28 985 SAMPLE MAXIMUM 73 .942 MODE VALUE 37 .882 OUANTILES -S 3 4 3 6 7 *S 35 . 365 MODE FROM NORMAL FIT 38 . 145 STANDARD DEV. NORMAL FIT 5 .651 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT STANDARD OEV. NORMAL 22.902 3. 558 15.87 1 34.224 2 1 .798 19.214 20.647 21.640 22 232 4 . 547 < 22.407> 23.340 24.791 26.568 41.574> 43.700 47.135 56.687 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN OEGREES CRANKSHAFT AFTER IGNITION < 52.055> 54.464 56.572 62.052 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 53 . 154 STANDARD DEVIATION 9 369 SAMPLE MINIMUM 31. 768 SAMPLE MAXIMUM - 86 724 MODE VALUE 47 224 OUANTILES -S 3 4 5 6 7 + S 44 391 MODE FROM NORMAL FI [T 50 539 STANDARD DEV. NORMAL F] IT 9 .992 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.567 STANDARD DEVIATION 0.014 SAMPLE MINIMUM 0.522 SAMPLE MAXIMUM 0.602 MODE VALUE 0.571 OUANTILES -S 3 4 5 6 7 +S 0.553 MOOE FROM NORMAL FIT 0.567 STANDARD DEV. NORMAL FIT 0.013 0.560 0.563 < 0.568> 0.571 0.574 0.581 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 57.691 7.697 41 .797 77.355 56.242 50.225 52.944 54.857 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 5.895 STANDARD DEVIATION O 403 SAMPLE MINIMUM 3.419 SAMPLE MAXIMUM 6.646 MOOE VALUE 6.075 OUANTILES -S 3 4 5 6 7 +S 5.588 MODE FROM NORMAL FIT 6.012 STANOARD DEV. NORMAL FIT 0.272 5.754 5.869 < 5.959> 6.048 6.105 6.256 FLAME TRAVEL BETWEEN PROBE 1 ft PR0BE2 IN OEGREES CRANKSHAFT < 56.670> 58.389 60.593 66.701 MODE FROM NORMAL FIT 55.927 SAMPLE AVERAGE 9 . 420 STANOARD DEV. NORMAL FIT 7.947 STANOARD DEVIATION 13 443 SAMPLE MINIMUM -28 .042 SAMPLE MAXIMUM 42 532 OF MAXIMUM PEAK PRESSURE. MEASURED IN OEGREES CRANKSHAFT AFTER TDC MODE VALUE 12 391 OUANTILES -S 3 4 5 6 7 *S -5 485 SAMPLE AVERAGE. 23.155 MODE FROM NORMAL FIT 12 .945 STANDARD DEVIATION 3.801 STANOARD DEV. NORMAL FIT 9 . 1 19 SAMPLE MINIMUM 7 . 137 SAMPLE MAXIMUM 36 053 MODE VALUE 22.499 OUANTILES -S 3 4 5 6 7 +S 19.891 21.394 22.174 < 23.012> 23.482 24.698 27.103 MODE FROM NORMAL FIT 22.579 STANOARD DEV. NORMAL FIT 1 .575 4.992 B.542 < 11.05B> 13.693 16.665 21.688 Experiment G2.8 P35 METHANE ENGINE S P E E D A I R FLOW R E L A T I V E A I R / F U E L R A T I O SPARK ADVANCE 2 5 0 0 . 0 RPM 1 0 0 . 0 % OF MAXIMUM 1 . t 3 5 . 0 DEGR BTDC SPARK P L U G : STANDARD P L U G 35 MOMENT OF F L A M E A R R I V A L AT ION PROBE 1 MEASUREO IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N SAMPLE A V E R A G E STANDARD D E V I A T I O N SAMPLE MINIMUM SAMPLE MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MODE FROM NORMAL F I T 37 .931 4 . 9 4 6 2 9 . 0 5 2 5 4 . 7 5 5 3 6 . 2 8 1 +S 3 3 . 1 2 9 3 5 . 2 4 9 3 6 . 3 4 1 3 6 . 6 7 3 < 3 7 . 4 6 7 > 3 8 . 9 7 4 4 0 . 4 3 1 4 4 . 2 2 7 MAXIMUM P E A K P R E S S U R E . MEASURED IN BAR S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 +S MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T WORK DONE DURING I N T A K E / E X H A U S T S T R O K E . M E A S U R E D IN BAR ( M E P ) STANDARD D E V . NORMAL F I T 4 . 0 4 2 MOMENT OF F L A M E A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 4 7 . 6 7 6 > 5 0 . 2 9 3 5 3 . 4 2 1 5 8 . 6 8 4 MOMENT OF F L A M E A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S C R A N K S H A F T A F T E R I G N I T I O N S A M P L E A V E R A G E 49 . 4 4 6 STANDARD D E V I A T I O N 9 . 4 6 5 SAMPLE MINIMUM 34 . 8 5 9 SAMPLE MAXIMUM 88 . 4 6 7 MODE V A L U E 44 . 3 5 2 O U A N T I L E S - S 3 4 5 6 7 * S 40 .631 MODE FROM NORMAL F l [T 45 . 8 4 5 STANDARD D E V . NORMAL F I T 8 . 0 8 5 S A M P L E A V E R A G E 0 . 5 1 7 S T A N D A R D D E V I A T I O N 0 0 1 9 S A M P L E MINIMUM 0 . 4 5 5 S A M P L E MAXIMUM 0 . 5 9 2 MODE V A L U E • 0 . 5 2 2 O U A N T I L E S - S 3 4 5 6 7 » S 0 . 4 9 8 MODE FROM NORMAL F I T 0 . 5 1 6 STANDARD D E V . NORMAL F I T 0 . 0 2 2 0 . 5 0 6 0 . 5 1 3 < O . S 1 7 > 0 . 5 2 2 0 . 5 2 6 0 . 5 3 6 S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 5 8 . 7 9 3 8 . 4 6 1 41 . 5 4 5 8 9 . 2 3 7 5 8 . 9 3 3 * S 5 0 . 3 2 2 5 4 . WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 7 . 6 5 6 STANDARD D E V I A T I O N 0 . 2 1 0 S A M P L E MINIMUM 6 . 8 3 2 S A M P L E MAXIMUM 8 . 1 7 4 MODE V A L U E 7 . 6 8 4 O U A N T I L E S - S 3 4 5 6 7 * S 7 . 4 7 8 MODE FROM NORMAL F I T 7 . 6 8 7 5TANDARD D E V . NORMAL F I T 0 . 1 2 9 7 . 5 9 1 7 . 6 3 1 < 7 . 6 7 1 > 7 . 7 0 1 7 . 7 4 1 7 . 8 3 7 181 5 7 . 2 0 5 < 5 9 . 2 6 4 > 6 1 . 5 9 6 6 4 . 5 4 9 7 0 . 3 3 6 F L A M E T R A V E L B E T W E E N PROBE 1 8 P R 0 B E 2 IN D E G R E E S C R A N K S H A F T MODE FROM NORMAL F I T 5 7 . 5 1 7 S A M P L E A V E R A G E 11 . 5 1 4 STANDARD D E V . NORMAL F I T 10 868 S T A N D A R O D E V I A T I O N 7 .941 S A M P L E MINIMUM - 18 . 4 2 6 S A M P L E MAXIMUM 45 . 736 OF MAXIMUM P E A K P R E S S U R E . MEASURED IN D E G R E E S CRANKSHAFT A F T E R TOC MODE V A L U E 8 . 977 O U A N T I L E S - S 3 4 5 6 7 +S 4 . 5 3 5 S A M P L E A V E R A G E 1 8 . 7 18 MODE FROM NORMAL F I T 8 .802 STANDARD D E V I A T I O N 2 . 6 3 4 STANDARD D E V . NORMAL F I T 5 . 347 S A M P L E MINIMUM 1 1 . 0 6 4 SAMPLE MAXIMUM 2 7 . 3 1 5 MODE V A L U E 1 8 . 3 4 3 F L A M E T R A V E L B E T W E E N P R O B E 2 8 P R O B E S IN I O U A N T I L E S - S 3 4 5 6 7 +S 16 .091 1 7 . 3 1 9 1 8 . 1 2 0 < 1 8 . 5 3 9 > 19 299 2 0 . 1 5 B 2 1 . 6 0 2 MODE FROM NORMAL F I T 1 9 . 3 B 1 S A M P L E A V E R A G E 9 347 STANDARD D E V . NORMAL F I T 3 . 3 0 6 S T A N D A R D D E V I A T I O N 9 728 S A M P L E MINIMUM - 3 2 962 S A M P L E MAXIMUM 4 0 3 5 0 MODE V A L U E 9 0 4 0 O U A N T I L E S - S 3 4 5 6 7 * S 0 . 576 MODE FROM NORMAL F I T 9 765 STANDARD D E V . NORMAL F I T 7 5 8 0 7 . 1 9 5 8 . 3 6 4 < 1 0 . 0 9 2 > 1 1 . 6 0 9 1 3 . 8 0 1 18 .141 5 . 4 5 6 7 . 6 2 1 < 9 . 5 7 0 > 1 1 . 4 7 8 1 3 . 7 8 5 1 8 . 1 4 8 Experiment M3.10 P35 25OO.0 RPM 10O.0 % OF MAXIMUM METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 1.1 SPARK ADVANCE 35.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 55 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 39 100 STANOARD DEVIATION 4. 605 SAMPLE MINIMUM 26 586 SAMPLE MAXIMUM 56 . 142 MOOE VALUE 37. 977 OUANTILES -S 3 4 5 6 7 *S 34 .907 MODE FROM NORMAL FIT 38 .201 STANDARO DEV. NORMAL FIT 4 999 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 50 .645 STANDARD DEVIATION 9 136 SAMPLE MINIMUM 32 . 1 17 SAMPLE MAXIMUM 84 .338 MODE VALUE 46 804 OUANTILES -S 3 4 5 6 7 *S 41 .688 MODE FROM NORMAL FIT 48 .462 STANDARD OEV. NORMAL FIT 9 .765 45.147 47.675 < 49.876> 51.960 54.786 60.019 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 60. 746 STANDARD DEVIATION 9 .046 SAMPLE MINIMUM 41 166 SAMPLE MAXIMUM 87 251 MODE VALUE 57 968 OUANTILES -S 3 4 5 6 7 »S 51. 463 MODE /ROM NORMAL FIT 59 739 STANDARD DEV. NORMAL FIT 12 .775 MOMENT OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE 17.421 2 .945 5.025 24 .741 17.142 OUANTILES -S 3 4 5 6 7 +S 14.581 15.946 16.621 MODE FROM NORMAL FIT 17.551 STANDARO OEV. NORMAL FIT 3.600 17.448> 18.352 19.213 20.324 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD OEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD OEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0 .522 STANDARD DEVIATION 0 .016 SAMPLE MINIMUM 0 .455 SAMPLE MAXIMUM 0 .567 MODE VALUE 0 .524 OUANTILES -S 3 4 5 6 7 *S 0 506 MODE FROM NORMAL FIT 0 524 STANDARD DEV. NORMAL FIT 0 .019 0.513 0.519 < 0.523> 0.527 0.532 0.539 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.440 STANDARD DEVIATION 0.174 SAMPLE MINIMUM 6.618 SAMPLE MAXIMUM 7.912 MODE VALUE 7.521 OUANTILES -S 3 4 5 6 7 *S 7.291 MODE FROM NORMAL FIT 7.502 STANDARD DEV. NORMAL FIT 0.155 7.383 7.434 < 7.477> 7.513 7.543 7.581 FLAME TRAVEL BETWEEN PROBE 1 ft PROBE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 11 .545 STANDARD DEVIATION 8 . 134 SAMPLE MINIMUM -15 .463 SAMPLE MAXIMUM 41 .668 MODE VALUE 1 1 .317 OUANTILES -S 3 4 5 6 7 •S 4 .334 MODE FROM NORMAL FIT 9 .629 STANDARD DEV. NORMAL FI IT 8 .017 6.746 8.763 < 10 752> 12.756 14.303 19.079 E x p e r i m e n t M 3 . l l P55 to o 2500.0 PPM 100.0 % OF MAXIMUM METHANE ENGINE SPEED AIP FLOW RELATIVE AIR/FUEL RATIO I.I SPARK ADVANCE 30.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 55 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 38. 518 STANDARD DEVIATION 4 . 702 SAMPLE MINIMUM 26. 978 SAMPLE MAXIMUM 54. 029 MODE VALUE 36. 840 OUANTILES -S 3 4 5 6 7 »S 34 . 068 36.203 37 . MODE FROM NORMAL FIT 37 . 649 STANDARD DEV. NORMAL FIT 5. 564 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN SAMPLE AVERAGE 52 567 STANDARD DEVIATION 11 . 044 SAMPLE MINIMUM 32 930 SAMPLE MAXIMUM 87. .272 MODE VALUE 45 950 OUANTILES -S 3 4 5 6 7 *S 42 . 136 46.104 47 . MODE FROM NORMAL FIT 47 .659 STANDARD OEV. NORMAL FIT 8 .499 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN SAMPLE AVERAGE 62 .442 STANDARD DEVIATION 9 .269 SAMPLE MINIMUM 40 .666 SAMPLE MAXIMUM 84 .410 MODE VALUE 60 .260 OUANTILES -S 3 4 5 6 7 *S 53 .609 57.402 59 MODE FROM NORMAL FIT 61 .534 STANDARD DEV. NORMAL FIT 11 .646 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREI SAMPLE AVERAGE 19 .371 STANDARD DEVIATION 3 . 130 SAMPLE MINIMUM 9 . 32 1 SAMPLE MAXIMUM 27 .391 MOOE VALUE 19 .297 OUANTILES -S 3 4 5 6 7 »S 16 .294 17.797 IB MODE FROM NORMAL FIT 20 . 307 STANDARD DEV. NORMAL FIT 4 .429 < 38.157> 40.023 41.182 44.566 S0.694> 53.314 57.136 63.034 < 61.473> 63.966 67.207 72 146 N EES CRANKSHAFT AFTER TDC 19.375> 20.374 21.461 22.730 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEPI SAMPLE AVERAGE 0.4B4 STANDARD DEVIATION 0.017 SAMPLE MINIMUM 0.437 SAMPLE MAXIMUM 0.537 MODE VALUE 0.486 OUANTILES -S 3 4 S 6 7 +S 0.467 MODE FROM NORMAL FIT 0.483 STANDARD DEV. NORMAL FIT 0.017 0.475 0.480 0.485> 0.489 0.493 0.503 WORK DONE DURING COMPRESS I ON/EXPANSION STROKE .MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.357 STANDARD DEVIATION 0.299 SAMPLE MINIMUM 6.297 SAMPLE MAXIMUM 7.925 MODE VALUE 7.297 OUANTILES -S 3 4 5 6 7 *S 7.062 MODE FROM NORMAL FIT 7.433 STANDARD OEV. NORMAL FIT 0.388 7.218 7.298 < 7.383> 7.463 7.564 7.679 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 14 .049 STANDARD DEVIATION 9 .777 SAMPLE MINIMUM -14 .740 SAMPLE MAXIMUM 49 .472 MOOE VALUE 1 1 .346 OUANTILES -S 3 4 5 6 7 +S 5 .653 MODE FROM NORMAL FIT 11 . 112 STANDARD DEV. NORMAL FIT 7 .506 .126 10.267 < 12.151> 14.303 16.778 22.737 Experiment M3.12 P55 N) METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 25O0.0 RPM 1OO.0 % OF MAXIMUM 1 . 1 40.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 55 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE OUANTILES -S 3 4 5 6 7 +S SAMPLE AVERAGE 41 . 164 MODE FROM NORMAL FIT STANDARD DEVIATION 5 .716 STANDARO DEV. NORMAL FIT SAMPLE MINIMUM 30 178 SAMPLE MAXIMUM 65 .581 MOOE VALUE 39 .398 WORK DONE DURING INTAKE/EXHAUST STROKE .MEASURED OUANTILES -S 3 A 5 6 7 »S 36 .134 38.125 39 357 < 40.419> 42.067 43.576 47.967 MODE EROM NORMAL FIT 39 633 SAMPLE AVERAGE 0 501 STANDARD DEV. NORMAL FIT 4 .615 STANDARD DEVIATION 0 019 SAMPLE MINIMUM 0 .443 SAMPLE MAXIMUM 0 .549 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN OEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 0 .510 OUANTILES -S 3 4 5 6 7 *S 0 .483 0.492 SAMPLE AVERAGE 50 221 MODE FROM NORMAL FIT 0 .503 STANDARD DEVIATION 8 .249 STANDARD OEV. NORMAL FIT 0 022 SAMPLE MINIMUM 33 .573 SAMPLE MAXIMUM 87 .446 MODE VALUE 46 .480 WORK DONE DURING COMPRESSION/EXPANSION STROKE.ME OUANTILES -S 3 4 5 6 7 *S 42 .330 45.344 47. 121 < 49.264> 51 136 53.893 59.098 MODE FROM NORMAL FIT 47 602 SAMPLE AVERAGE 7 543 STANDARD OEV. NORMAL FIT 7 .841 STANDARO OEVIATION 0 . 193 SAMPLE MINIMUM 6 884 SAMPLE MAXIMUM 7 941 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN OEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 7 .424 OUANTILES -S 3 4 5 6 7 *S 7 366 7.422 SAMPLE AVERAGE 59 831 MODE FROM NORMAL FIT 7 . 434 STANDARD DEVIATION 8 847 STANDARD DEV. NORMAL FIT O. 091 SAMPLE MINIMUM 40 .565 SAMPLE MAXIMUM 87 877 MODE VALUE 55 .843 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES OUANTILES -S 3 4 5 6 7 *S 50 .604 54.546 56 438 < 58.621> 60.780 63.468 68.701 MOOE FROM NORMAL FIT 55 .384 SAMPLE AVERAGE 9 057 STANDARD OEV. NORMAL FIT 8 887 STANDARD DEVIATION 8 842 SAMPLE MINIMUM 23 159 SAMPLE MAXIMUM 42. 078 DF MAXIMUM PEAK PRESSURE, MEASURED IN OEGREES CRANKSHAFT AFTER TDC MODE VALUE 7. 421 OUANTILES -S 3 4 5-6 7 *S 2 . 565 4.969 SAMPLE AVERAGE 16 676 MODE FROM NORMAL FIT 8. 424 STANDARD DEVIATION 2 .774 STANDARD DEV. NORMAL FIT 7 . 699 SAMPLE MINIMUM 9 .562 SAMPLE MAXIMUM 23 . 177 MOOE VALUE 16 .511 OUANTILES -S 3 4 5 6 7 »S 13 .718 15.036 15. 814 < 16.519> 17.249 18.212 19 658 MODE FROM NORMAL FIT 16 .275 STANDARD DEV. NORMAL FIT 3 .032 IN BAR (MEP) 0.497 < 0.502> 0.506 0.511 0.519 7.451 < 7.490> 7.542 7.696 7.813 7.008 < 8.610> 10.505 12.552 16.602 Experiment M3.13 P55 to to METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE SPARK PLUG: NGK MULT I 2500.0 RPM 100.0 % OF MAXIMUM 35.0 DEGR BTOC MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 37. 217 STANDARO DEVIATION 4 . 665 SAMPLE MINIMUM 26. 717 SAMPLE MAXIMUM 58 . 908 MODE VALUE 35. 771 OUANTILES -S 3 4 5 6 7 »S 33 007 34. 958 35 MODE FROM NORMAL FIT 36. . 1 15 STANDARD DEV. NORMAL FIT 3. .251 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN SAMPLE AVERAGE 46 222 STANDARD DEVIATION 7 847 SAMPLE MINIMUM 30 .404 SAMPLE MAXIMUM 87 .315 MODE VALUE 45 .225 OUANTILES -S 3 4 5 6 7 *S 38 .905 41 978 43 MODE FROM NORMAL FIT 43 .563 STANDARO DEV. NORMAL FIT 5 .564 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN SAMPLE AVERAGE 56 .560 STANDARD DEVIATION 8 .683 SAMPLE MINIMUM 38 . 102 SAMPLE MAXIMUM 88 .857 MODE VALUE 50 .262 OUANTILES -S 3 4 5 6 7 +S 48 .493 50 .719 52 MODE FROM NORMAL FIT 55 .285 STANDARD DEV. NORMAL FIT 11 .004 44.967> 46.823 48.911 53.898 < 55.836> 58.068 60.688 63.690 MOMENT OF MAXIMUM PEAK PRESSURE, MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 17.554 2 .668 9.761 24.057 IB.249 14.953 16.128 17.671 3 .465 16.647 < 17.646> 18.288 19.114 20.340 MAXIMUM PEAK PRESSURE, MEA5URE0 IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 *S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.516 STANDARD OEVIATION 0.016 SAMPLE MINIMUM 0.475 SAMPLE MAXIMUM 0.564 MODE VALUE 0.517 OUANTILES -S 3 4 5 6 7 +S 0.500 MODE FROM NORMAL FIT 0.516 STANDARD DEV. NORMAL FIT 0.019 0.508 0.512 < 0.517> 0.521 0.525 0.533 WORK DONE DURING COMPRESSION/EXPANSION STROKE,MEASURED IN BAR (MEP) SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 496 850 356 287 358 095 7.333 7.364 < 7.396> 7.426 7.557 7.681 FLAME TRAVEL BETWEEN PROBE 1 ft PROBE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 9.005 STANDARD DEVIATION 7.611 SAMPLE MINIMUM -18.961 SAMPLE MAXIMUM 39.333 MODE VALUE 8.364 OUANTILES -S 3 4 5 6 7 +S 2.769 MODE FROM NORMAL FIT 7.316 STANDARD DEV. NORMAL FIT 4.934 5.372 6.965 < 8.228> 9.491 11.223 16.229 Experiment M3.14 NGK to CO METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE SPARK PLUG: NGK MULTI 25O0.0 RPM tOO.O % OF MAXIMUM dO.O DEGR BTDC MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 40.576 6.715 25.809 64.048 39.750 OUANTILES -S 3 4 5 6 7 *S 34.795 36.760 38.354 < 39 964> 41.134 43.043 48.207 MODE FROM NORMAL FIT 38.553 STANDARD DEV. NORMAL FIT 6.043 SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 45.863 STANDARD DEVIATION 7.411 SAMPLE MINIMUM 29.894 SAMPLE MAXIMUM 73.081 MODE VALUE 43.840 OUANTILES -S 3 4 5 6 7 +S 38.740 41.558 43.434 < 45.009> 46.833 48.925 53.756 MODE FROM NORMAL FIT 43.333 STANDARD DEV. NORMAL FIT 5.842 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 54.910 8.026 34.030 83.476 52.057 OUANTILES -S 3 4 5 6 7 +5 47.708 51.094 52.920 < 55.074> 57.302 60.285 69. MODE FROM NORMAL FIT 52.872 STANDARD DEV. NORMAL FIT 7.880 SAMPLE AVERAGE STANDARD OEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE MOMENT OF MAXIMUM PEAK PRESSURE, MEASURED IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE 14.985 STANDARD OEVIATION 2.929 SAMPLE MINIMUM 6.607 SAMPLE MAXIMUM 22.670 MODE VALUE 15.140 OUANTILES -S 3 4 5 6 7 +S 12.072 MODE FROM NORMAL FIT 14.916 STANDARD DEV. NORMAL FIT 3.125 13.346 14.233 < 15.057> 15.699 16.324 18.040 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP> SAMPLE AVERAGE 0.504 STANDARD OEVIATION 0.017 SAMPLE MINIMUM 0.432 SAMPLE MAXIMUM 0.555 MODE VALUE 0.510 OUANTILES -S 3 4 5 6 7 *S 0.487 MOOE FROM NORMAL FIT O-505 STANDARD DEV. NORMAL FIT 0.021 04 9 6 0.500 < 0.506> 0.510 0 5 1 5 0.523 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.585 STANDARD DEVIATION 0.178 SAMPLE MINIMUM 6.503 SAMPLE MAXIMUM 7.817 MOOE VALUE • 7.694 OUANTILES -S 3 4 5 6 7 +S 7.379 MODE FROM NORMAL FIT 7.667 STANDARO DEV. NORMAL FIT 0.122 7.576 7.607 < 7.636> 7.669 7.697 7.733 FLAME TRAVEL BETWEEN PROBE 1 ft PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 5. 286 STANDARD DEVIATION 9 215 SAMPLE MINIMUM -28 109 SAMPLE MAXIMUM 34 . 990 MODE VALUE 5. 412 OUANTILES -S 3 4 5 6 7 *S -0 787 MODE FROM NORMAL FIT 6 605 STANDARD DEV. NORMAL FIT 5 .315 2.946 4.539 < 5.938> 7.440 9.009 12.242 FLAME TRAVEL BETWEEN PR0BE2 & PROBE3 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 9 .047 STANDARD DEVIATION 7 .608 SAMPLE MINIMUM -2 1 .221 SAMPLE MAXIMUM 39 .056 MODE VALUE 7 034 OUANTILES -S 3 4 5 6 7 *S 2 . 133 MODE FROM NORMAL FIT 8 . 180 STANDARD OEV. NORMAL FIT 6 .718 5.567 6.983 8.606> 10.224 12.318 15.811 Experiment M3.15 NGK METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE SPARK PLUG: NGK MULTI 2500. 10O.C 0 RPM % OF MAXIMUM 30.0 DEGR BTDC MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN OEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 *'. MODE FROM NORMAL FIT STANOARD OEV. NORMAL FIT 35 .612 4 . 110 26. 391 48.694 35.916 31.862 33.718 34.706 34 .579 4.219 < 35.699> 36.690 37.729 40.909 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MOOE VALUE OUANTILES -S 3 4 5 6 7 +« MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 46.883 8.420 29.909 82.186 41 . 344 38.769 41 .723 43.953 44.969 10.008 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 -*S MODE FROM NORMAL FIT STANOARD DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.483 STANDARD DEVIATION 0.017 SAMPLE MINIMUM 0.433 SAMPLE MAXIMUM 0.547 MODE VALUE 0.482 OUANTILES -S 3 4 5 6 7 *S 0.465 MODE FROM NORMAL FIT 0.482 STANDARD OEV. NORMAL FIT 0.013 0.473 0.479 < 0.483> 0.486 0.492 0.502 < 45.986> 48.619 50.797 55.407 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 MOOE FROM NORMAL FIT STANDARO DEV. NORMAL FIT MOMENT OF MAXIMUM PEAK PRESSURE. SAMPLE AVERAGE STANDARD OEVIATION SAMPLE MINIMUM 9.238 SAMPLE MAXIMUM 27.217 MODE VALUE 22.161 OUANTILES -S 3 4 5 6 7 +S 17.096 MODE FROM NORMAL FIT 20.390 STANDARD DEV. NORMAL FIT 3.465 56.974 9.667 37.223 83.089 49.167 +S 46.941 50.164 53.355 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.499 STANDARD DEVIATION 0.222 SAMPLE MINIMUM 5.908 SAMPLE MAXIMUM 7.842 MODE VALUE 7.620 OUANTILES -S 3 4 5 6 7 +S 7.293 MODE FROM NORMAL FIT 7.609 STANDARD DEV. NORMAL FIT 0.201 7.404 7.492 < 7.547> 7.608 7.641 7.709 < 56.199> 58.016 61.376 67.547 FLAME TRAVEL BETWEEN PROBE 1 » PROBE2 IN DEGREES CRANKSHAFT 53.352 SAMPLE AVERAGE 1 1 .272 11. B84 STANDARO DEVIATION 7 336 SAMPLE MINIMUM -5 .032 SAMPLE MAXIMUM 42 .430 MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE a .316 OUANTILES -S 3 4 5 6 7 »S 3 .855 19.897 MODE FROM NORMAL FIT 9 .222 2.760 STANDARD DEV. NORMAL FIT 8 258 6.914 8.506 < 10.149> 12.076 13.812 17.763 18.328 19.18 < 19.996> 20.586 21.476 22.324 Experiment M3.16 NGK 2500.0 RPM 65.0 % OF MAXIMUM METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 1.1 SPARK ADVANCE 30.0 OEGR BTDC SPARK PLUG: STANDARD PLUG 55 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION 32.643> 33.588 35.287 38.621 MOMENT OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 33. 051 STANDARD DEVIATION 4, .549 SAMPLE MINIMUM 21 .307 SAMPLE MAXIMUM. 50 576 MODE VALUE 32 .588 OUANTILES -S 3 4 S 6 7 *S 28 .716 MODE FROM NORMAL FIT 31 .209 STANDARO DEV. NORMAL FIT 4 .455 SAMPLE AVERAGE 48. 939 STANDARD DEVIATION 9. 872 SAMPLE MINIMUM 31 .701 SAMPLE MAXIMUM 86 .410 MODE VALUE 44 .808 OUANTILES -S 3 4 5 6 7 *S 39 .487 MODE FROM NORMAL FIT 44 612 STANDARD DEV. NORMAL FIT 4 .410 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARO DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE,MEASURED IN BAR (MEP) SAMPLE AVERAGE 0.517 STANDARD DEVIATION 0.014 SAMPLE MINIMUM 0.480 SAMPLE MAXIMUM 0.550 MODE VALUE 0.5 17 OUANTILES -S 3 4 5 6 7 +S 0.502 MODE FROM NORMAL FIT 0.517 STANDARD DEV. NORMAL FIT 0.014 0.509 0.514 < 0.517> 0.520 0.525 0.533 MOMENT OF FLAME ARRIVAL AT ION PROBE 3 MEASUREO IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES - 5 3 4 5 MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 67 .571 11.598 39.963 123.744 82.726 S 55.939 61.197 63.792 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 5.729 STANDARD DEVIATION 0.154 SAMPLE MINIMUM 5.178 SAMPLE MAXIMUM 6.023 MODE VALUE 5.855 OUANTILES -S 3 4 5 6 7 +S 5.566 MOOE FROM NORMAL FIT 5.788 STANDARD DEV. NORMAL FIT 0.166 5.671 5.707 < 5.750> 5.789 5.834 5.872 < 67.883> 70.860 75.850 82.125 FLAME TRAVEL BETWEEN PROBE 1 & PROBE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE STANOARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 71 .009 SAMPLE AVERAGE 15. 887 21.712 STANDARD DEVIATION 9 190 SAMPLE MINIMUM -5. 349 SAMPLE MAXIMUM 47 . 837 MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE 10. 717 OUANTILES -S 3 4 5 6 7 *S 7. 794 21.727 MODE FROM NORMAL FIT 1 1 . 7 17 2.889 STANDARD DEV. NORMAL FIT 6 .563 10.224 12.051 < 14.059> 15.939 19.007 24.059 14.614 27.993 19.491 S 18.857 19.899 20.561 < 21.645> 22.500 23.463 25.157 FLAME TRAVEL BETWEEN PR0BE2 * PROBES IN DEGREES CRANKSHAFT 21.192 SAMPLE AVERAGE 18. 632 3.362 STANDARD DEVIATION 11 . 482 SAMPLE MINIMUM -24 774 SAMPLE MAXIMUM 48 742 MOOE VALUE 20 408 OUANTILES -S 3 4 5 6 7 *S 6. 827 MODE FROM NORMAL FIT 20 647 STANOARD DEV. NORMAL FIT 8 334 13.200 16.954 < 19.394> 21.777 24.354 30.157 E x p e r i m e n t M3.20 P55 to 2500.0 RP" 65.0 % OF MAX I MUM METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 1.1 SPARK ADVANCE 35.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION SAMPLE AVERAGE 36. 104 STANDARD DEVIATION 4 . 822 SAMPLE MINIMUM 23. 976 SAMPLE MAXIMUM 58. 650 MODE VALUE 35 . 895 OUANTILES -S 3 4 5 6 7 +S 31 . 537 33.818 34 . MODE FROM NORMAL FIT 35. 120 STANDARD DEV. NORMAL FIT 4 . 904 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN SAMPLE AVERAGE 50. 338 STANDARO DEVIATION 9 117 SAMPLE MINIMUM 34 . 496 SAMPLE MAXIMUM 84 . 969 MODE VALUE 45. 537 OUANTILES -S 3 4 5 6 7 *S 41 . 812 44.978 46. MODE FROM NORMAL FIT 47. 557 STANDARD OEV. NORMAL FIT 8. .670 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN SAMPLE AVERAGE 68 .002 STANDARD DEVIATION 12 .312 SAMPLE MINIMUM 42 . 133 SAMPLE MAXIMUM 113 .5B5 MODE VALUE 57 763 OUANTILES -S 3 4 5 6 7 *S 55 . 290 59.549 63 MODE FROM NORMAL FIT 69 .406 STANDARD DEV. NORMAL FIT 25 .882 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREI SAMPLE AVERAGE 19 .956 STANDARD DEVIATION 2 930 SAMPLE MINIMUM 1 1 .976 SAMPLE MAXIMUM 30 .740 MODE VALUE 20 .381 OUANTILES -S 3 4 5 6 7 +S 17 .206 18.348 19 MOOE FROM NORMAL FIT 19 .434 STANDARD DEV. NORMAL FIT 3 . 192 35.944> 37.009 38.669 41.276 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT WORK DONE OURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 0 5 1 8 STANDARD DEVIATION 0.014 SAMPLE MINIMUM 0.480 SAMPLE MAXIMUM 0.55B MODE VALUE 0.523 OUANTILES -S 3 4 5 6 7 *S 0-504 MODE FROM NORMAL FIT 0.519 STANDARO DEV. NORMAL FIT 0.019 0.511 0.515 < 0.519> 0.523 0.526 0.533 WORK DONE OURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAH (MEP) SAMPLE AVERAGE 5.763 STANDARD DEVIATION 0.121 SAMPLE MINIMUM 5.092 SAMPLE MAXIMUM 5.992 MODE VALUE 5.B33 OUANTILES -S 3 4 5 6 7 +S 5.647 MODE FROM NORMAL FIT 5.811 STANDARD DEV. NORMAL FIT 0.127 5.718 5.750 < 5.7B6> 5.819 5.843 5.fl FLAME TRAVEL BETWEEN PROBE 1 ft PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 14 233 STANDARD DEVIATION B. 343 SAMPLE MINIMUM -9 293 SAMPLE MAXIMUM 45 824 MODE VALUE 10 802 OUANTILES -S 3 4 5 6 7 *S 6. 572 MOOE FROM NORMAL FIT 11. 898 STANDARD DEV. NORMAL FIT 6. 288 IAVEL BETWEEN PR0BE2 8 PROBE 3 IN I SAMPLE AVERAGE 17 664 STANDARD DEVIATION 15 .957 SAMPLE MINIMUM -32 .525 SAMPLE MAXIMUM 65 .006 MOOE VALUE 1 1 . 160 OUANTILES -S 3 4 5 6 7 *S 0 .516 MODE FROM NORMAL FIT 19 . 274 STANDARD OEV. NORMAL FIT 19 .956 9.637 11.118 < 13.136> 14.833 17.165 21.923 9.224 12.654 < 17.156> 21.705 27.014 33.721 Experiment M3.21 P35 to 2525.0 RPM 65.0 % OF MAXIMUM METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO 1.1 SPARK ADVANCE 40.0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MOMENT OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 *S SAMPLE AVERAGE 37 . 278 MODE FROM NORMAL FIT STANDARD DEVIATION 6 .018 STANDARD OEV. NORMAL FIT SAMPLE MINIMUM 26 .201 SAMPLE MAXIMUM 62 506 MOOE VALUE 34 .899 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASURED IN BAR (MEP) OUANTILES - 5 3 4 5 6 7 »S 31 .586 34.278 35 433 < 36.803> 37.801 39.616 42.616 MOOE FROM NORMAL FIT 36 .257 SAMPLE AVERAGE 0.521 STANDARD OEV. NORMAL FIT 4 .015 STANDARD DEVIATION 0.016 SAMPLE MINIMUM 0.481 SAMPLE MAXIMUM 0.560 OF FLAME ARRIVAL AT ION PROBE 2 MEASUREO IN OEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 0.525 OUANTILES -S 3 4 S 6 7 *S 0.504 0.511 0.518 < 0.522> 0 SAMPLE AVERAGE 48 259 MODE FROM NORMAL FIT 0.518 STANOARD DEVIATION 7 .311 STANDARD DEV. NORMAL FIT 0.022 SAMPLE MINIMUM 33 820 SAMPLE MAXIMUM 70 .758 MODE VALUE 42 669 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 6 7 +S 41 .211 43.538 45 377 < 47.649> 49.461 51.666 56.210 MODE FROM NORMAL FI IT 46 .249 SAMPLE AVERAGE 5.668 STANDARD DEV. NORMAL FIT 7 .851 STANDARD DEVIATION 0. 162 SAMPLE MINIMUM 4.739 SAMPLE MAXIMUM 5.880 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 5.749 .525 0.529 0.538 SAMPLE AVERAGE 63 310 STANDARD DEVIATION 11. 969 SAMPLE MINIMUM 37. .808 SAMPLE MAXIMUM 94 473 MODE VALUE 60. 828 OUANTILES -S 3 4 5 6 7 <-S 51 .264 MODE FROM NORMAL FIT 57. .333 STANDARD OEV. NORMAL FIT 10 443 OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 5.512 5. 741 0.099 5.654 5.685 < 5.720> 5.745 5.763 5.795 < 61.320> 64.145 68.682 75.786 FLAME TRAVEL BETWEEN PROBE 1 ft PROBE2 IN DEGREES CRANKSHAFT MOMENT OF MAXIMUM PEAK PRESSURE. MEASUREO IN DEGREES CRANKSHAFT AFTER TDC SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT 16.886 2 .966 8. 19 f 24.952 17 .444 13.909 15.311 16.373 17 .370 1 . 148 SAMPLE AVERAGE 10 980 STANDARD OEVIATION 7 682 SAMPLE MINIMUM -21 .685 SAMPLE MAXIMUM 36 345 MOOE VALUE 9 . 143 OUANTILES -S 3 4 5 6 7 *S 4 693 MODE FROM NORMAL FIT 10 .614 STANDARD DEV. NORMAL FIT 5 . 748 7.861 9.147 < 10.642> 12.310 14.505 17.601 < 17.236> 17.636 18.263 19.917 ExDeriment M3.22 P35 to 00 2 4 6 5 . 0 RPM 1 O O . 0 % OF MAXIMUM METHANE ENGINE S P E E D AIR FLOW R E L A T I V E A I R / F U E L R A T I O 1.1 SPARK ADVANCE 3 5 . 0 DEGR BTDC SPARK P L U G : STANDARD P L U G 35 SAMPLE A V E R A G E 35 9 4 0 STANDARD D E V I A T I O N 4 . 9 7 0 S A M P L E MINIMUM 22 656 S A M P L E MAXIMUM 59 .331 MODE V A L U E 36 154 O U A N T I L E S - S 3 4 S 6 7 * S 31 . 336 MODE FROM NORMAL F I T 35 0 6 9 STANDARD O E V . NORMAL F I T 4 . 544 MOMENT OF FLAME A R R I V A L AT ION PROBE 1 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N < 3 5 . 8 9 8 > 3 7 . 0 9 1 3 8 . 6 8 4 4 2 . 0 3 3 MOMENT OF FLAME A R R I V A L AT ION PROBE 2 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N 4 B . 9 9 7 > 5 1 . 3 3 9 5 3 . 9 3 0 6 0 . 5 7 9 MOMENT OF FLAME A R R I V A L AT ION PROBE 3 MEASURED IN D E G R E E S CRANKSHAFT A F T E R I G N I T I O N S A M P L E A V E R A G E 5 0 . 876 STANDARD D E V I A T I O N 10. 523 S A M P L E MINIMUM 28 859 SAMPLE MAXIMUM 91 . 403 MODE V A L U E 46 . 4 5 0 O U A N T I L E S - S 3 4 5 6 7 * S 41 544 MODE FROM NORMAL F I T 46 .992 STANDARO D E V . NORMAL F I T 8 . 416 MAXIMUM P E A K P R E S S U R E , MEASURED IN BAR S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 +S MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T WORK DONE D U R I N G I N T A K E / E X H A U S T S T R O K E , M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 0 . 5 1 1 STANDARD D E V I A T I O N 0 . 0 1 5 S A M P L E MINIMUM 0 . 4 6 7 S A M P L E MAXIMUM 0 . 5 5 0 MODE V A L U E 0 . 5 1 1 O U A N T I L E S - S 3 4 5 6 7 +S 0 . 4 9 5 MODE FROM NORMAL F I T 0 . 5 0 8 STANDARD D E V . NORMAL F I T 0 . 0 0 9 0 . 5 0 3 0 . 5 0 6 < 0 . 5 1 1 > 0 . 5 1 3 0 . 5 2 0 0 . 5 2 7 SAMPLE A V E R A G E STANDARD D E V I A T I O N SAMPLE MINIMUM SAMPLE MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 MOOE FROM NORMAL F I T STANDARD D E V . NORMAL 5 9 . 4 9 1 1 0 . 1 6 1 3 5 . 2 8 0 8 7 . 9 5 4 5 9 . 9 7 1 +S 4 9 . 2 2 4 5 3 . 1 7 0 5 6 . 1 0 6 < 5 9 . 4 4 0 > WORK DONE DURING C O M P R E S S I O N / E X P A N S I O N S T R O K E . M E A S U R E D IN BAR ( M E P ) S A M P L E A V E R A G E 7 . 5 2 1 STANDARD D E V I A T I O N 0 . 2 2 3 SAMPLE MINIMUM 6 . 5 B 5 S A M P L E MAXIMUM 7 . 8 8 0 MODE V A L U E 7 . 7 3 2 O U A N T I L E S - S 3 4 5 6 7 +S 7 . 3 2 6 MODE FROM NORMAL F I T > 7 . 6 0 6 STANDARD D E V . NORMAL F I T 0 . 2 9 7 7 . 4 2 6 7 . 4 7 8 < 7 . 5 4 6 > 7 . 6 2 1 7 . 6 8 3 7 . 7 4 2 F L A M E T R A V E L B E T W E E N PROBE 1 ft P R 0 B E 2 IN D E G R E E S C R A N K S H A F T 11.421 6 5 . 1 9 5 7 1 . 5 5 0 . MOMENT OF MAXIMUM PEAK P R E S S U R E , MEASURED S A M P L E A V E R A G E STANDARD D E V I A T I O N S A M P L E MINIMUM S A M P L E MAXIMUM MODE V A L U E O U A N T I L E S - S 3 4 5 6 7 +S MODE FROM NORMAL F I T STANDARD D E V . NORMAL F I T 5 7 . 1 6 6 .' S A M P L E A V E R A G E 14 9 3 6 1 5 . 0 4 2 STANDARD D E V I A T I O N 9 . 7 8 8 S A M P L E MINIMUM - 1 9 632 S A M P L E MAXIMUM 57 . 9 6 B  IN D E G R E E S C R A N K S H A F T A F T E R TDC MODE V A L U E 10 . 2 7 6 O U A N T I L E S - S 3 4 5 6 7 * S 6 . 7 6 6 1 8 . 5 8 4 MODE FROM NORMAL F I T 1 1 .014 2 . 8 6 0 STANDARD D E V . NORMAL F I T 5 BOB 1 1 . 5 6 7 2 7 . 7 3 5 1 7 . 4 6 2 FLAME T R A V E L B E T W E E N P R 0 B E 2 8 PROBE 3 IN I i 1 5 . 3 2 2 1 7 . 1 7 5 1 7 . 5 5 3 < 1 8 . 5 1 2 > 1 9 . 3 6 3 2 0 . 2 7 8 2 1 . 8 6 5 1 8 . 6 1 4 S A M P L E A V E R A G E 8 6 1 5 2 . 8 2 6 STANDARO D E V I A T I O N 10 .534 S A M P L E MINIMUM - 2 7 . 157 S A M P L E MAXIMUM 5 0 654 MOOE V A L U E 9 . 317 O U A N T I L E S - S 3 4 5 6 7 +S - 0 .711 MODE FROM NORMAL F I T 10 0 0 0 STANDARD D E V . NORMAL F I T 9 . 9 3 5 9 . 3 1 1 1 0 . 9 6 2 < 1 3 . 0 2 1 > 1 4 . 7 6 6 1 7 . 7 6 7 2 3 . 6 8 9  D E G R E E S C R A N K S H A F T 4 . 0 9 9 7 . 0 3 8 < 9 . 0 6 4 > 1 1 . 5 0 2 1 3 . 9 9 8 1 8 . 3 6 2 E x p e r i m e n t M3.24 P35 to LO METHANE ENGINE SPEED 25OO.0 RPM AIR FLOW (00.0 % OF MAXIMUM RELATIVE AIR/FUEL RATIO 1.1 SPARK ADVANCE 40-0 DEGR BTDC SPARK PLUG: STANDARD PLUG 35 MAXIMUM PEAK PRESSURE. MEASURED IN BAR SAMPLE AVERAGE STANDARD OEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE OUANTILES -S 3 4 5 6 7 *S SAMPLE AVERAGE 38 049 MODE FROM NORMAL FIT STANDARD DEVIATION 5 260 STANDARD DEV. NORMAL FIT SAMPLE MINIMUM 26 619 SAMPLE MAXIMUM 61 .306 MODE VALUE 37 .097 WORK DONE DURING INTAKE/EXHAUST STROKE.MEASUREO IN BAR (MEP) OUANTILES -S 3 4 5 6 7 + S 32 .790 35.205 36 .531 < 37.654> 38.834 40.429 43.090 MODE FROM NORMAL FIT 37 .403 SAMPLE AVERAGE 0. 506 STANDARD DEV. NORMAL F] IT 3 .469 STANDARD DEVIATION 0. 016 SAMPLE MINIMUM 0 466 SAMPLE MAXIMUM 0. 554 DF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 0. 500 OUANTILES -S 3 4 5 6 7 *S 0 490 0.499 0.501 < 0 505> 0. SAMPLE AVERAGE 50 .470 MODE FROM NORMAL FIT 0. 507 STANDARD DEVIATION 9 226 STANDARO DEV. NORMAL FIT 0. 020 SAMPLE MINIMUM 31 .790 SAMPLE MAXIMUM. 95 .572 MODE VALUE 48 400 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) OUANTILES -S 3 4 5 6 7 *S 4 1 946 44.916 47 .071 < 49.045> 51.433 53.823 59.257 MODE FROM NORMAL FIT 47 .419 SAMPLE AVERAGE 7. 383 STANDARD DEV. NORMAL FIT 8 .347 STANDARD DEVIATION 0 202 SAMPLE MINIMUM 6 366 SAMPLE MAXIMUM 7, 748 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN DEGREES CRANKSHAFT AFTER IGNITION MODE VALUE 7. 273 OUANTILES -S 3 4 5 6 7 *S 7. .204 7.269 7 . 300 < 7 . 329> 7 SAMPLE AVERAGE 58 867 MODE FROM NORMAL FIT 7. 414 STANDARD DEVIATION 8 928 STANDARD DEV. NORMAL FIT 0. 364 SAMPLE MINIMUM 39 .297 SAMPLE MAXIMUM 93 . 172 MODE VALUE 56 .694 FLAME TRAVEL BETWEEN PROBE 1 8 PR0BE2 IN DEGREES CRANKSHAFT OUANTILES -S 3 4 5 6 7 •S 50 .360 53.441 55 .567 < 57.714> 59.881 62.471 67.537 MODE FROM NORMAL FIT 56 035 SAMPLE AVERAGE 12 421 STANDARD DEV. NORMAL FI IT 10 .084 STANDARO DEVIATION 9 068 SAMPLE MINIMUM 21 559 SAMPLE MAXIMUM 46 334 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREES CRANKSHAFT AFTER TDC MODE VALUE 10 266 OUANTILES -S 3 4 5 6 7 *S 4 . 981 8.049 9.936 < 11.186> 13 SAMPLE AVERAGE 16 249 MODE FROM NORMAL FIT 10 357 STANDARD DEVIATION 2 .636 STANDARD DEV. NORMAL FIT 5. 712 SAMPLE MINIMUM 9 .956 SAMPLE MAXIMUM 23 .684 MODE VALUE 16 . 391 FLAME TRAVEL BETWEEN PROBE2 8 PROBES IN DEGREES CRANKSHAFT OUANTILES -S 3 4 5 6 7 *S 13 .442 14.572 15 .406 < 16.237> 16.618 17.642 19.363 MODE FROM NORMAL FIT 15 .454 SAMPLE AVERAGE 8 397 STANDARD DEV. NORMAL FIT 2 . 124 STANDARD DEVIATION 9. 328 SAMPLE MINIMUM 27 554 SAMPLE MAXIMUM 46 522 MODE VALUE 10. 256 OUANTILES -S 3 4 5 6 7 +S 0. ,771 4.317 6.354 < 8.517> 10 MODE FROM NORMAL FIT 8 581 STANDARD DEV. NORMAL FIT 8 856 510 0.515 0.522 450 7.558 7.623 15.289 20.587 E x p e r i m e n t M3.25 P35 METHANE ENGINE SPEED AIR FLOW RELATIVE AIR/FUEL RATIO SPARK ADVANCE 30.0 DEGR BTDC SPAPK PLUG: STANDARD PLUG 35 2475.0 RPM 100.0 % OF MAXIMUM OF FLAME ARRIVAL AT ION PROBE 1 MEASURED IN SAMPLE AVERAGE 3G. 025 STANDARD DEVIATION 5. 207 SAMPLE MINIMUM 23. 627 SAMPLE MAXIMUM 54. 769 MODE VALUE 36. 927 OUANTILES -S 3 4 5 6 7 *S 31 . 034 33.102 34. MOOE FROM NORMAL FIT 34. 529 STANDARD DEV. NORMAL FIT 5. 601 OF FLAME ARRIVAL AT ION PROBE 2 MEASURED IN SAMPLE AVERAGE 54. 570 STANDARD DEVIATION 12. 900 SAMPLE MINIMUM 30 570 SAMPLE MAXIMUM 115 427 MODE VALUE 49 132 OUANTILES -S 3 4 5 6 7 +S 42 .684 46.956 49. MODE FROM NORMAL FIT 49 . 106 STANDARD DEV. NORMAL Fl IT 9 .618 OF FLAME ARRIVAL AT ION PROBE 3 MEASURED IN SAMPLE AVERAGE ' 62 .319 STANDARD DEVIATION 11 .233 SAMPLE MINIMUM 34 .746 SAMPLE MAXIMUM 111 .354 MODE VALUE 59 .484 OUANTILES -S 3 4 5 6 7 *S 51 .419 56.507 58 MODE FROM NORMAL FIT 60 .064 STANDARD DEV. NORMAL FIT 9 892 OF MAXIMUM PEAK PRESSURE. MEASURED IN DEGREI SAMPLE AVERAGE 19 .090 ' STANDARD OEVIATION 3 .438 SAMPLE MINIMUM 8 .444 SAMPLE MAXIMUM 28 .915 MODE VALUE IB 893 OUANTILES -S 3 4 5 6 7 +S 15 .577 17.343 18 MODE FROM NORMAL FIT 19 .632 STANDARD DEV. NORMAL FIT 4 . 897 < 52.154> 54.981 59.259 65.617 61.489> 64.394 67.623 74.242 < 19.097> 19.860 21.025 22.774 MAXIMUM PEAK PRESSURE, MEASURED IN BAR SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD DEV. NORMAL FIT WORK DONE DURING INTAKE/EXHAUST STROKE . MEASURED IN BAR (MEP ) SAMPLE AVERAGE STANDARD DEVIATION SAMPLE MINIMUM SAMPLE MAXIMUM MODE VALUE OUANTILES -S 3 4 5 6 7 +S MODE FROM NORMAL FIT STANDARD OEV. NORMAL FIT 0.499 0.016 0.452 0.548 0.503 0. 484 0.500 0.018 0.491 0.496 < 0.50O> 0.504 0 508 0.515 WORK DONE DURING COMPRESSION/EXPANSION STROKE.MEASURED IN BAR (MEP) SAMPLE AVERAGE 7.174 STANDARD DEVIATION 0.315 SAMFLE MINIMUM 5.953 SAMPLE MAXIMUM 7.729 MODE VALUE 7 . 304 OUANTILES -S 3 4 5 6 7 +S 6.863 MODE FROM NORMAL FIT 7.248 STANDARD DEV. NORMAL FIT 0.240 7.054 7.139 < 7.210> 7.293 7.343 7.485 FLAME TRAVEL BETWEEN PROBE 1 » PR0BE2 IN DEGREES CRANKSHAFT SAMPLE AVERAGE 18 .544 STANDARD DEVIATION 1 1 .874 SAMPLE MINIMUM -6 .902 SAMPLE MAXIMUM 84 .685 MODE VALUE 13 133 OUANTILES -S 3 4 5 6 7 +S 8 .059 MODE FROM NORMAL FIT 14 .793 STANDARD DEV. NORMAL FIT 8 . 110 13 926 < 16.223> IB.760 22.063 29.026 FLAME TRAVEL BETWEEN PROBE2 8 PROBES IN DEGREES CRANKSHAFT SAMPLE AVERAGE 7. 749 STANDARD DEVIATION 12 064 SAMPLE MINIMUM -50 209 SAMPLE MAXIMUM 44 913 MOOE VALUE 10 233 OUANTILES -S 3 4 5 6 7 +S -3. . 109 MODE FROM NORMAL FIT 10 . 149 STANDARD DEV. NORMAL FIT 8 . 135 3.145 6.254 < 8 859> 11.138 13.660 18 616 E x p e r i m e n t M3.26 P35 CO 132 Appendix G. Data A c q u i s i t i o n System C i r c u i t Drawings high voltage 100k O ion probe signal •O ion probe pulse Fig.49 : i o n probe s i g n a l a m p l i f i e r C A clockc p u i s e o — — [ | y-4093B 0 C L Q 4013B CL 4013B S R_ Fig.50: l a t c h c i r c u i t © arrival time 100mV=loCA 4081B clock CL-rxii_Qjnjnj-Ln_ _J 1 signal 0. Q-STB . JT 133 JL BDCQ V 330k +V ;3k3 r in 0 J lOOki 47k, L 7 _ ~ir CA in 2 degrees f330k —I—r +v 4030B I 3 4 t 3k3 339 y 150k 4093B l n "^ 1093B q R Q 4081B 4093B J - lWl54 «k7 BDC -°out CA +V IM 10k 1 0 u = 339 +V 10k 1 degree adjust when two LED's are on, turn trimmer clockwards until one LED goes off. Readjust for every engine speed. This ensures 50* duty cycle of clock O MSB 'Fig .51: crankangle degree counter 134 +5V 4050B L S B o _ £ > _ | "Bo—1> 1°—>• I—> at : > - H > |o—1> S o — [ > MSBO £ > — j EPROM 2716J 0/A AD7520LN ,470p H R * I741TC -Ovolume V pressure 10H EPROM 2716J D/A AD7520LN I, 10k metal/fin LF355 M JJ/f metal/fin -OPa« metal/fi>Tj :F355I pressure O — — metal/fin -O peak pressure p +V +V 3k3 <^J-i—I -v^  : 33k ^ 1 L " l ^ V +v +v k 330k | |>7k BDC at end of intake stroke 33k I lSk 339 s 3k3 _Q pulse at peak pressure 9 P P 4-. Ik5 Fig.52: V,pdV/da,p generator - P Fig.53: imep integrator 100k ' v p 68k 100k i LF35 L7 470 metal/fin IF35 10k imep power stroke 10k r r i e t a l / f ln P41TC 2 120k 100k 68k 39k logic switch 0 1 on off 2 4-4 4 L7 470 nfetal/fin 10nx" 100k? V LF355, metal/ 741TCS- _o l m e p total engine cycle -O I M E P pumping loss BDC O-4093B rH>"H£> • +v 4093B 330k| ^ lOOn 4093B 4027B BDC ~"]_J~ 1 NAND BDC" NAND EDT U 4 ~~ 3 

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