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Performance of a dual-fuel prechamber diesel engine with natural gas Song, Seaho 1984

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PERFORMANCE DIESEL  OF A  DUAL-FUEL  PRECHAMBER  E N G I N E WITH NATURAL  GAS  BY  SEAHO .Sc.,  A  (SONG  The U n i v e r s i t y  of B r i t i s h  T H E S I S SUBMITTED THE  IN P A R T I A L  REQUIREMENTS MASTER  OF  FOR  Columbia,  FULFILLMENT  THE DEGREE  APPLIED  1  OF  SCIENCE  in THE THE  F A C U L T Y OF  DEPARTMENT  We  accept to  THE  GRADUATE  OF M E C H A N I C A L  this  thesis  the required  UNIVERSITY May ©Seaho  OF  as  STUDIES ENGINEERING  conforming  standard  B R I T I S H COLUMBIA  1984 Song,  1984  In p r e s e n t i n g  t h i s thesis in p a r t i a l fulfilment  of  the  r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y  of  B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t freely  available  agree t h a t  for  permisiion  reference for  extensive  t h e s i s f o r s c h o l a r l y purposes may of my  Department or  and  study.  I further  copying  financial  written  gain  by h i s or her  shall  not  representatives.  be  permission.  Department of M e c h a n i c a l E n g i n e e r i n g The U n i v e r s i t y of B r i t i s h Columbia 2324 Main M a l l Vancouver, Canada V6T 1W5 Date:  June  1984  this  be g r a n t e d by the Head  i s u n d e r s t o o d t h a t c o p y i n g or p u b l i c a t i o n of t h i s for  of  It  thesis  allowed without  my  ii ABSTRACT The f e a s i b i l i t y of d u a l - f u e l o p e r a t i o n w i t h n a t u r a l gas i n a  prechamber  d i e s e l engine was s t u d i e d w i t h s p e c i a l emphasis on  f u e l consumption and c y l i n d e r p r e s s u r e development.  The e f f e c t s  of a i r r e s t r i c t i o n , p i l o t d i e s e l flow r a t e and i n j e c t i o n were  also  studied.  timing  D u a l - f u e l o p e r a t i o n showed poor p a r t - l o a d  f u e l consumption; near f u l l l o a d t h e f u e l consumption was to  that  of  straight  diesel  operation.  In  i n j e c t i o n t i m i n g adjustment t h e maximum power fuel  operation  pressure. reducing  was  Retarding t h e maximum  severely the  limited  injection  cylinder  close  t h e absence of  output  of  dual-  by t h e maximum c y l i n d e r  timing  was  effective in  pressure to a safe l e v e l .  The  a n a l y s i s of apparent energy r e l e a s e i n d i c a t e s t h e d i f f e r e n c e s i n combustion mechanism between a u t o - i g n i t i o n straight  diesel  operation  dual-fuel  operation.  and  of  diesel  fuel  in  p r o p a g a t i o n of flame f r o n t s i n  iii T a b l e of Contents  Abstract i i L i s t of T a b l e s iv L i s t of F i g u r e s y Acknowledgements viii Nomenclature ix I . INTRODUCTION 1 1 .1 Background 1 1.2 P r e s e n t Study 7 I I . REVIEW OF LITERATURE 10 2.1 H i s t o r y of D u a l - F u e l D i e s e l Engine 10 2.2 Review of Research 12 I I I . APPARATUS AND INSTRUMENTATION ... 26 3.1 Engine and Test Bed • 26 3.2 I n s t r u m e n t a t i o n 38 3.3 F u e l 43 3.4 Data P r o c e s s 45 IV. EXPERIMENTAL RESULTS 47 4.1 F u e l Consumption 47 4.1.1 F u e l Consumption w i t h U n m o d i f i e d Engine .. 47 4.1.2 E f f e c t of R e s t r i c t i n g I n t a k e A i r 55 4.1.3 E f f e c t of V a r y i n g I n j e c t i o n Timing 56 4.2 C y l i n d e r P r e s s u r e 63 4.2.1 C y l i n d e r P r e s s u r e i n U n m o d i f i e d Engine ... 63 4.2.2 E f f e c t of R e s t r i c t i n g I n t a k e A i r 74 • 4.2.3 E f f e c t of V a r y i n g I n j e c t i o n T i m i n g 79 V. ANALYSIS OF APPARENT ENERGY RELEASE 84 5.1 G e n e r a l 84 5.2 Method of C a l c u l a t i o n 85 5.2.1 D e f i n i t i o n s , E q u a t i o n s , and Assumptions .. 85 5.2.2 Computation Procedure 98 5.3 A n a l y s i s 107 5.3.1 O p e r a t i o n w i t h Unmodified Engine 107 5.3.2 E f f e c t of R e s t r i c t i n g I n t a k e A i r 124 5.3.3 E f f e c t of V a r y i n g I n j e c t i o n T i m i n g ....... 130 V I . CONCLUSIONS AND RECOMMENDATIONS 135 6.1 C o n c l u s i o n s 135 6.2 Recommendations 138 BIBLIOGRAPHY APPENDIX A - CALIBRATION CURVES APPENDIX B - COMPUTATION OF INDICATED MEAN EFFECTIVE PRESSURE APPENDIX C - COMPUTER PROGRAM FOR DATA ACQUISITION .... APPENDIX D - COMPUTER PROGRAM FOR DATA PROCESS APPENDIX E - COMPUTER PROGRAM FOR APPARENT ENERGY RELEASE  139 142 146 148 157 162  iv  L i s t of Tables  2.1 3.1 3.2 3.3 5.1 5.2  Summary of Past E x p e r i m e n t a l Work Engine S p e c i f i c a t i o n T y p i c a l c o m p o s i t i o n of the N a t u r a l Gas Used T y p i c a l Output of Computer Program f o r Data Processing Comparison of A c t u a l and Computed F u e l Energy Consumed . . E f f e c t of I n t a k e A i r R e s t r i c t i o n on M i x t u r e Temperature a t Top Dead Center  13 29 44 46 105 126  V  L i s t of F i g u r e s  1.1 2.1 2.2 2.3 2.4 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14  Combustion Chambers o f . D i r e c t - I n j e c t i o n and Prechamber Engines E f f e c t of G a s - A i r M i x t u r e S t r e n g t h on I g n i t i o n delay T y p i c a l Pressure-Time Trace of Non-Knocking and Knocking O p e r a t i o n . . w • V a r i a t i o n of Power Output w i t h t h e O v e r a l l M i x t u r e S t r e n g t h f o r D i f f e r e n t I n t a k e Tempertures T y p i c a l Thermal E f f i c i e n c i e s of D u a l - F u e l and Straight D i e s e l Operation Apparatus and I n s t r u m e n t a t i o n Flow of A i r , F u e l , and Exhaust Gas Shape of Combustion Chambers Sleeve M e t e r i n g F u e l System F u e l I n j e c t i o n Pump and Housing Seqence of I n j e c t i o n E v e n t s Governor Components of S l e e v e M e t e r i n g Fuel I n j e c t i o n Nozzle Turbocharger Cutaway View Gas M i x e r Mounting of C y l i n d e r P r e s s u r e Transducer E f f e c t of P i l o t D i e s e l Flow Rate on Brake Thermal Efficiency F u e l Consumption a t i d l i n g O p e r a t i o n E f f e c t of p i l o t D i e s e l Flow Rate on I n d i c a t e d Thermal E f f i c i e n c y Comparison of Brake Thermal e f f i c i e n c i e s f o r D u a l - F u e l and S t r a i g h t D i e s e l O p e r a t i o n E f f e c t of I n t a k e A i r R e s t r i c t i o n on Brake Thermal E f f i c i e n c y T y p i c a l C y l i n d e r P r e s s u r e Trace and Apparent P o i n t of I g n i t i o n S t a r t Apparent P o i n t of I g n i t i o n S t a r t a t V a r i o u s Loads E f f e c t of V a r y i n g I n j e c t i o n Timing on Brake Thermal E f f i c i e n c y P-V Diagram of S t r a i g h t D i e s e l O p e r a t i o n Ln P-V Diagram of S t r a i g h t D i e s e l O p e r a t i o n Comparison of P-V Diagrams f o r D u a l - F u e l and S t r a i g h t D i e s e l O p e r a t i o n Comparison of Ln P-V Diagrams f o r D u a l - F u e l and S t r a i g h t D i e s e l O p e r a t i o n Comparison of Maximum C y l i n d e r P r e s s u r e s f o r D u a l - F u e l and S t r a i g h t D i e s e l O p e r a t i o n Maximum C y l i n d e r P r e s s u r e a t V a r i o u s Loads  5 17 21 22 25 27 28 30 32 32 33 33 34 36 37 39 48 50 52 54 57 58 59 61 64 66 67 69 70 71  vi 4.15 Comparison of Maximum Rate of C y l i n d e r P r e s s u r e R i s e f o r D u a l - F u e l and S t r a i g h t D i e s e l Operation 4.16 Maximum Rate of C y l i n d e r P r e s s u r e R i s e a t V a r i o u s Loads 4.17 E f f e c t of I n t a k e A i r R e s t r i c t i o n on Maximum Cylinder Pressure 4.18 E f f e c t of I n t a k e A i r R e s t r i c t i o n P r e s s u r e P r i o r to Combustion 4.19 E f f e c t of I n t a k e A i r R e s t r i c t i o n on Maximum Rate of C y l i n d e r P r e s s u r e R i s e 4.20 E f f e c t of V a r y i n g I n j e c t i o n Timing on Maximum c y l i n d e r P r e s s u r e and Rate of P r e s s u r e R i s e 4.21 E f f e c t of V a r y i n g I n j e c t i o n Timing on P r e s s u r e P r i o r t o Combustion and P o i n t of I g n i t i o n S t a r t .. 4.22 E f f e c t of V a r y i n g I n j e c t i o n Timing on P-V Diagram 5.1 C o n t r o l Volume f o r Apparent Energy R e l e a s e Analysis 5.2 Apparent Heat T r a n s f e r Rate and Heat T r a n s f e r Model 5.3 E f f e c t of Heat T r a n s f e r Model on Apparent Rate of Energy Release 5.4 E f f e c t of E q u i l i b r i u m C a l c u l a t i o n on Apparent Rate of Energy Release 5.5 E f f e c t of Smoothing P r e s s u r e Data on Apparent r a t e of Energy Release 5.6 F l o w c h a r t of Computer Program f o r Apparent Energy Release 5.7 T y p i c a l Output of Computer Program f o r Apparent Energy R e l e a s e A n a l y s i s 5.8 Rate of Energy Release of S t r a i g h t D i e s e l O p e r a t i o n a t V a r i o u s Loads 5.9 Cumulative Energy Release of S t r a i g h t D i e s e l O p e r a t i o n a t V a r i o u s Loads 5.10 E f f e c t of A i r - F u e l R a t i o on Maximum Rate of Energy R e l e a s e i n S t r a i g h t D i e s e l O p e r a t i o n 5.11 Rate of Energy Release of D u a l - F u e l O p e r a t i o n a t V a r i o u s Loads 5.12 E f f e c t of G a s - A i r M i x t u r e S t r e n g t h on Maximum Rate of Energy R e l e a s e i n D u a l - F u e l O p e r a t i o n .... 5.13 Cumulative Energy R e l e s e of D u a l - F u e l O p e r a t i o n at V a r i o u s Loads 5.14 Comparison of Rate of Energy R e l e a s e f o r S t r a i g h t D i e s e l and D u a l - F u e l O p e r a t i o n 5.15 Comparison of Cumulative Energy R e l e a s e f o r S t r a i g h t D i e s e l and D u a l - F u e l O p e r a t i o n 5.16 Rate of Energy R e l e a s e of D u a l - F u e l O p e r a t i o n at V a r i o u s P i l o t D i e s e l Flow Rates  72 73 75 76 78 80 81 82 86 91 93 97 101 103 104 108 109 111 112 113 115 116 117 118  vii 5.17 5.18 5.19 5.20 5.21 5.22 5.23 5.24 5.25 5.26 5.27 5.28  Cumulative Energy Release of D u a l - F u e l O p e r a t i o n at V a r i o u s P i l o t D i e s e l Flow Rats F r a c t i o n of F u e l Burnt i n Low Load D u a l - F u e l Operation Rate of Energy R e l e a s e of D u a l - F u e l O p e r a t i o n at V a r i o u s P i l o t D i e s e l Flow Rates C u m u l a t i v e Energy Release of D u a l - F u e l O p e r a t i o n at V a r i o u s P i l o t D i e s e l Flow Rates E f f e c t of R e s t r i c t i n g I n t a k e A i r on Rate of Energy R e l e a s e E f f e c t of R e s t r i c t i n g I n t a k e A i r on C u m u l a t i v e Energy Release E f f e c t of R e s t r i c t i n g I n t a k e A i r on Rate of Energy Release E f f e c t of R e s t r i c t i n g I n t a k e A i r on C u m u l a t i v e Energy Release E f f e c t of Advancing I n j e c t i o n Timing on Rate of Energy Release E f f e c t of Advancing I n j e c t i o n Timing on Cumulative Energy Release E f f e c t of R e t a r d i n g I n j e c t i o n Timing on Rate of Energy Release E f f e c t of R e t a r d i n g I n j e c t i o n Timing on Cumulative Energy Release  \  120 121 122 123 125 127 128 129 131 132 133 134  vi i i Acknowledgement The author  wishes t o acknowledge  a  for  encouragement.  Dr. P.G. H i l l  his  advice  and  sincere  gratitude  d i s c u s s i o n s w i t h Dr. Roger M i l a n e have and w i l l remain to  the  author.  Thanks  Osaka, and John Hoar f o r setting  up  the  installation  of  instrumentation  are  Numerous valuable  a l s o due t o Messrs Stan Mah,  technical  advice  and  to  assistance  Shu in  equipments.  Stan Mah was r e s p o n s i b l e f o r the  the  engine,  and  before  the  project  for  development  commenced.  of  the  P r o v i s i o n of  t e c h n i c a l i n f o r m a t i o n and a s s i s t a n c e by Mr. J i m Bare of F i n n i n g s Tractors i s greatly appreciated. members  of  the  F u r t h e r thanks a r e due t o  the  t h e s i s committee, Dr. B. A h l b o r n , Dr. B. Evans  and Dr. E.G. Hauptmann. This  work  was  financially  supported  Department of Energy Mines and R e s o u r c e s .  by  the  Federal  ix  Nomenclature A ATDC BMEP BTDC CA CE D E e K k m^ N P Q q R T U V V W V  area after top dead center brake mean e f f e c t i v e pressure before top dead center crank angle chemical energy bore energy internal energy of combustion equilibrium constant thermal conductivity mass of fuel number of moles pressure heat transfer heat transfer rate Reynolds Number temperture internal energy volume mean velocity work equilibrium composition  v p $ X  viscosity density equivalence r a t i o inverse of equivalence r a t i o  c  Subscripts: 9 i  gas state  m  2  kPa kJ mm kJ kJ/kg kW/(irt' C) kg kmole MPa kJ kW C kJ m m/s kJ 3  kg/m-s kg/m 3  1  CH.I  Introduction  1 .1 Background  Dual-Fuel  D i e s e l Engines w i t h N a t u r a l Gas  D u a l - f u e l d i e s e l engines a r e here d e f i n e d burn  e i t h e r gaseous  The mode of o p e r a t i o n diesel  i s defined  as  straight  lean  gas-air  ratio  and  diesel  i f only  stroke,  diesel  fuel  i s mixed  the m i x t u r e  d u r i n g t h e compression s t r o k e .  compression  i s then  Near the end  of the  f u e l i s i n j e c t e d and a u t o - i g n i t e s ,  i n i t i a t i n g the combustion of the g a s - a i r  mixture.  Because  t h e mode  of  operation,  The  changeover  e i t h e r from d u a l - f u e l t o s t r a i g h t  d i e s e l o r s t r a i g h t d i e s e l t o d u a l - f u e l can take p l a c e w h i l e engine  characteristics  of  dual-fuel operation  from t h o s e of s t r a i g h t d i e s e l o p e r a t i o n . combustion  In d i e s e l  differ  operation  t a k e s p l a c e s w i t h i n s m a l l zones where the f u e l -  a i r r a t i o i s s u i t a b l e f o r combustion. fuel  the  operates.  Combustion  the  of  f u n c t i o n t o i n i t i a t e the combustion the d i e s e l i n d u a l - f u e l  o p e r a t i o n i s o f t e n r e f e r r e d t o as p i l o t d i e s e l . of  which  f u e l s or d i e s e l , or both a t t h e same time.  In d u a l - f u e l o p e r a t i o n the gaseous  a i r at  compressed  its  those  f u e l i s used, and d u a l - f u e l i f two f u e l s a r e used a t the  same t i m e . with  as  As  a  stream  of  diesel  i s i n j e c t e d i n t o t h e c y l i n d e r , i t i s mixed w i t h a i r t o be  d i s i n t e g r a t e d i n t o f i n e d r o p l e t s which  i n turn  vapourize  and  2 auto-ignite  due t o the h i g h temperature of the compressed a i r .  The time p e r i o d d u r i n g which l i q u i d d i e s e l i s mixed w i t h a i r and v a p o u r i z e d i s r e f e r r e d t o as ' p h y s i c a l d e l a y ' and the time taken from then t o the p o i n t j u s t p r i o r t o i g n i t i o n i s r e f e r r e d t o 'chemical  delay'.  commonly  termed  operation,  These  two  'ignition  delay  as  p e r i o d s a r e combined and  delay'.  Combustion  in  dual-fuel  i n c o n t r a s t , o c c u r s i n a n e a r l y homogeneous f u e l - a i r  mixture.  D u r i n g the i n t a k e s t r o k e , a n e a r l y u n i f o r m m i x t u r e  of  gas  air  by  and  is  drawn  into  the c y l i n d e r , then compressed  p i s t o n movement t o h i g h temperature and p r e s s u r e enough  to  e l i c i t auto-ignition.  but  not  high  A s m a l l amount of d i e s e l  fuel  i s i n j e c t e d i n t o the homogeneous g a s - a i r m i x t u r e near the end of the compression s t r o k e . goes  through  the  The  injected pilot diesel  ignition  delay before i t d i s i n t e g r a t e s  d i e s e l ' vapour t o i n i t i a t e flame f r o n t s which the g a s - a i r m i x t u r e . responsible mixture.  for  subsequent  operation  operation.  The to  differs  combustion  in  auto-ignition  from  of  pilot  combustion  that  straight  of  process  straight  diesel  of  diesel  operation  is  of d i e s e l f u e l , whereas t h a t of  d u a l - f u e l o p e r a t i o n depends h e a v i l y on characteristics  through  combustion of the r e m a i n i n g g a s - a i r  I t i s i n t h i s r e g a r d t h a t the  due  propagate  into  The p r o p a g a t i o n of flame f r o n t s i s l a r g e l y  dual-fuel  largely  subsequently  diesel  both  the  auto-ignition  and the p r o p a g a t i o n of flame  fronts. The gaseous  f u e l we a r e concerned w i t h here i s n a t u r a l gas.  N a t u r a l gas i s a v a i l a b l e i n most places  localities,  and  more abundant than o t h e r k i n d s of f u e l .  at which the n a t u r a l gas a u t o - i g n i t e s i s  higher  is  The  in  many  temperature  than  that  of  3  other  available  ignition high low  temperature  compression cost  natural in  gaseous  of gas  places  operate of  where  the  straight  The the  same has  in  the  supply  power  past  as  may  has  with  such  power  is nearly  has  shown  to  rise.  type  as  of  of  in  a  with  of  diesel  operation  combustion  c h a r a c t e r i s t i c s at  consumption  natural  gas  because  of  consumption  rate.  survive lean rate  combustion gas-air  can  be  at  full than  amount than  pipe  diesel  line  has  that  of  of  10%  rate  load  pilot  of  total  industries,  dual-fuel  engines  load,  diesel  low  load  and  escape  improved  may  which  low  mixture  the  cylinder to  be  the  engine  advantage  be  offset  result  significant through  strength. by  of  dual-fuel  economic  load  load,  rate  is limited  is believed  If  the  full  operation  high  engine.  at  At  as  its  dual-fuel  range  less  engines  satisfactory.  spark-ignition  over  the  been  consumption  gas  constant,  dual-fuel  knock  Knock in  operate  power  of  the with  have  where  better  Typically,  with  especially  gas  fuel  natural  to  interrupted.  stations  sometimes  applications  be  auto-  operation  production,  The  consisted  This,  natural  load.  high  compressed  diesel  power  with  be  the  be  possibly  required been  can  generating  or  dual-fuel  fuel  for  full  of  auto-ignition.  engines  near  good  mixture  dual-fuel  operation  In  occurrence  to  makes  operation.  maximum  pressure  at  as  input.  operation  by  be  diesel  the  in  diesel  to  used  energy where  diesel  constantly  shown  diesel  gas  extensively  dual-fuel  been  gas,  Because  without  a t t r a c t i v e means  Dual-fuel employed  gas-air  ratio  natural an  the  fuels.  Low  restricting  by in  of poor poor  amounts  the  of  exhaust  load  fuel  intake  air,  4  which  effectively  increasing which  the  pilot diesel  improve low  i n t a k e charge diesel.  increases  advancing  P r e h e a t i n g the  gaseous  thus  fuel.  time f o r the reaction  Diesel  injection  assists  the  engine  an  the  prechamber  can  be  reaction  subsequent  one  or two  pressure, r i s e  and  main  combustion  engine chamber.  chambers The  the  the  the  initial  types: d i r e c t whether  Fig. for  f u e l i n the will  drive  the  so  advantages of the  diesel  1.1  two  shows  the  direct-injection  volume of the  prechamber  the  of  prechamber i s  volume.  The  prechamber d e s i g n i s to burn a s m a l l  t u r b u l e n c e w i l l promote r a p i d and  the  to  consisting  that  the  main  fraction resulting  m i x t u r e of p a r t i a l l y burnt  unburned f u e l i n t o the main chamber as a h i g h  The  of  A prechamber  chambers.  t y p i c a l l y 20 t o 30 p e r c e n t of the c l e a r a n c e  injected  pilot  in higher mixture  c l a s s i f i e d i n t o two  prechamber d i e s e l e n g i n e s .  of  of  the  i n j e c t i o n t i m i n g p r o v i d e s longer  indirect-injection  t y p i c a l shape of the  of the  timing  oxidation  methods  preheating  i n d i r e c t - i n j e c t i o n t y p e s depending on involves  objective  possible  by  Engine  combustion  and  s t r e n g t h , or  pilot diesel.  engines  i n j e c t i o n or  Other  i n t a k e charge r e s u l t s  Advancing  Prechamber D i e s e l  chambers,  the  gaseous f u e l to r e a c t  of the  is  flow r a t e .  mixture  l o a d f u e l consumption r a t e are  and  temperature and  gas-air  speed  jet  and  whose  complete combustion.  prechamber d i e s e l engine compared to  d i r e c t - i n j e c t i o n type are  better  emission  characteristics  F i g u r e 1 .1 - Combustion Chambers of D i r e c t - I n j e c t i o n and Prechamber Engines  6  and  less  tendency  to  knock.  c h a r a c t e r i s t i c s the prechamber speed  operations.  Because of the b e t t e r  emmision  engines are p r e f e r r e d f o r  higher  The d i s a d v a n t a g e s a r e m a i n l y a s s o c i a t e d w i t h  higher surface-to-volume r a t i o t h r o t t l i n g between prechamber  which  enhances  and main chamber.  heat  loss  and  These r e s u l t i n  h i g h e r f u e l consumption r a t e . The  type of d i e s e l engine used i n d u a l - f u e l o p e r a t i o n  n a t u r a l gas has been  almost  that  of  the  behaviour  a  exclusively prechamber  with  direct-injection,  so  d i e s e l engine w i t h d u a l -  f u e l l i n g over a range of l o a d appears t o be v i r t u a l l y unknown.  7  1.2 P r e s e n t  Study  Object ives The p r i m a r y o b j e c t i v e of t h i s study was feasibility prechamber  of  diesel  consumption critically  dual-fuel  and affect  consumption  and  operation  engine.  engine cylinder  with  Observations  cylinder  pressure durability. pressure  to  determine  natural were  gas  made  development The  the in  of  fuel  which  effects  of the f o l l o w i n g  a  on  may fuel  variables  were s t u d i e d : a. flow r a t e of p i l o t  diesel  b. g a s - a i r m i x t u r e s t r e n g t h c. i n j e c t i o n t i m i n g of p i l o t Computer a n a l y s i s of apparent study  the combustion  Past  energy  release  characteristics, first  o p e r a t i o n and then w i t h r e g a r d variables.  diesel  experience  to  the  was  employed  for straight  above  three  diesel  operating  w i t h d i r e c t - i n j e c t i o n engines  considered in a n t i c i p a t i n g possible operating i n a n a l y z i n g the observed combustion  to  difficulties  was and  characteristics.  E x p e r i m e n t a l Work A C a t e r p i l l a r 3304, f o u r - c y l i n d e r prechamber marine e n g i n e , with  turbocharger  was  used  e x p e r i m e n t a l study was done at load  in  the course of the study.  constant  engine  speed  The  because  changes r a t h e r than speed changes were c o n s i d e r e d t o be of  8  chief  concern  operation.  i n examining  the  feasibility  The  first  consumption  fuel  rate  rates.  I t was  load'  that  t o near f u l l  the d u a l - f u e l o p e r a t i o n diesel operation. affect  pressure.  rate  I t was observed  would become lower than t h a t of s t r a i g h t was  the e f f e c t of p i l o t d i e s e l flow  shown t o  s e v e r e l y ' l i m i t e d •by  As t h e  rate  and p r e s s u r e  r a p i d l y with increase  i n load.  became  r i s e were  .The maximum  the maximum  cylinder  I t was found t h a t when t h e flow r a t e of p i l o t d i e s e l  was below a c e r t a i n l i m i t misfirings. region  consumption  l o a d t h e f u e l consumption r a t e of  maximum c y l i n d e r p r e s s u r e  was  than As the  the f u e l consumption r a t e a t low l o a d s .  observed t o i n c r e a s e power output  load the f u e l  fuel higher  a t loads much lower  The flow r a t e of p i l o t d i e s e l  l o a d was i n c r e a s e d The  the  i s considerably  of s t r a i g h t d i e s e l o p e r a t i o n .  t h a t a t some p o i n t beyond f u l l  smaller.  that  loads  s p e c i f i e d by t h e engine m a n u f a c t u r e r .  l o a d was i n c r e a s e d approached  found  of d u a l - f u e l o p e r a t i o n  than t h a t of s t r a i g h t d i e s e l o p e r a t i o n 'full  data.  phase of t e s t s was performed w i t h v a r i o u s  and p i l o t d i e s e l  greatly  dual-fuel  Throughout t h e e x p e r i m e n t s measurments were taken t o  produce f u e l consumption and c y l i n d e r p r e s s u r e  the  of  of  the  operation  became  erratic  with  F o r a range of l o a d s and p i l o t d i e s e l f l o w r a t e s , a unstable  operation  due t o i n s u f f i c i e n t p i l o t d i e s e l  flow r a t e was e s t a b l i s h e d . The of  the  second phase of t h e e x p e r i m e n t s was i n t e n d e d effect  of  intake a i r r e s t r i c t i o n .  stage of t h e e x p e r i m e n t s restriction  can  cause  i t was surge  noticed of  f o r study  During the i n i t i a l that  excessive a i r  the compressor  i n the  9  turbocharger.  S i n c e surge can e a s i l y cause m e c h a n i c a l damage of  the t u r b o c h a r g e r t h e i n t a k e a i r r e s t r i c t i o n had t o be l i m i t e d t o a s m a l l range of a i r f l o w r e d u c t i o n . In the l a s t stage of experiments t h e e f f e c t timing  was  studied  primarily  pressures associated with timing.  I t was  found  and  retarding  normal  the  r e s u l t s i n s i g n i f i c a n t r e d u c t i o n i n both p r e s s u r e and p r e s s u r e r i s e .  injection  because of concern over maximum  dual-fuelling that  of  injection  injection  t h e maximum  timing  cylinder  The change i n f u e l consumption  rate  due t o the r e t a r d e d i n j e c t i o n was found t o be s m a l l .  Computer A n a l y s i s of Apparent Energy A  computer  Release  program which computes apparent energy  release  due t o combustion was developed i n order t o study the combustion characteristics.  The c y l i n d e r p r e s s u r e d a t a o b t a i n e d d u r i n g the  course of above t h r e e phases of e x p e r i m e n t s analysis.  The  analysis  cylinder pressure combustion  energy  consistent  with  ignition  was  showed  mainly  release. different  that  results  mechanisms  used  the e x c e s s i v e  associated The  were  of  with  high  i n the maximum rate  of  of t h e a n a l y s i s a r e combustion:  auto-  of d i e s e l i n s t r a i g h t d i e s e l o p e r a t i o n and p r o p a g a t i o n  of flame f r o n t s i n d u a l - f u e l  operation.  10  CH.II Review of L i t e r a t u r e  2.1 H i s t o r y of t h e D u a l - F u e l D i e s e l Engine The e a r l i e s t p r a c t i c a l use of gas as an engine back  to  called  the  end  of  the 19th c e n t u r y .  fuel  dates  S p a r k - i g n i t e d engines  'gas e n g i n e s ' o p e r a t e d i n much t h e same way as modern gas  engines.  In t h e s e  early  engines  the g a s - a i r  mixtures  were  n e a r l y s t o i c h i o m e t r i c and t h e compression r a t i o s were about 6:1. Commercial  p r o d u c t i o n of e n g i n e s of v a r i o u s s i z e s began i n about  the  1900.  year  Jones(l944)  states  that  by 1920 i n B r i t a i n  engines w i t h maximum power r a n g i n g from 5 t o 2000 horse power (4 to  1500 kW) were manufactured  f o r use  mainly  on  waste  gases,  p a r t i c u l a r l y b l a s t furnace gas. The  first  attempt  to  burn gas i n a compression  ignition  engine appears t o have been made by the C.&G. Cooper Company 1927.  According  to  Boyer  and  Crooks(1951),  the f i r s t  in test  c o n s i s t e d of i n j e c t i n g n a t u r a l gas a l o n e a t h i g h p r e s s u r e a t the end of t h e compression firing  of  stroke.  This  resulted  in  irregular  t h e gas. In t h e next t e s t a s m a l l p o r t i o n of d i e s e l  was i n j e c t e d i n a d d i t i o n t o t h e gas. T h i s was t h e b i r t h of the so  called  'gas-diesel'  engine,  i n which t h e gaseous  i n j e c t e d i n t o the c y l i n d e r a t h i g h p r e s s u r e (about 7 MPa).  The  first  1000 p s i  kW)  operation  engine was  or  commercial i n s t a l l a t i o n of such engine was  a c h i e v e d by t h e Nordberg Company i n 1935. A 1,665 (1,241  f u e l was  was  installed  successful;  at  at  full  Lubbock, load  the  horse  power  Texas, and the specific  fuel  11  consumption was The  high  as low as t h a t of d i e s e l o p e r a t i o n . pressure  ' g a s - d i e s e l ' engines costly  and  thus  rather d i f f i c u l t Company  gave r i s e t o problems:  limited  to  to m a i n t a i n .  developed  used town gas.  gas i n j e c t i o n equipment needed f o r the  an  the  equipment  use on l a r g e e n g i n e s , and In 1938  the N a t i o n a l Gas  i t was  and  Oil  8 - c y l i n d e r 440 horse power e n g i n e ,  In t h i s engine  the  gas  was  was  admitted  which  to  the  c y l i n d e r a t low p r e s s u r e through a s e p a r a t e passage from the a i r inlet.  The  o p e r a t i o n was  of e x i s t i n g engines Tame and Rea An  at the C o l e s h i l l  such  alternative  of  the  Birmingham  means of a d m i t t i n g the gas at low  scheme  M i t c h e l l and  developed  better  admitted  i n t o the c y l i n d e r , gas was after  gas-air  upstream  Whitehouse(1954)  pressure described  by the E n g l i s h E l e c t r i c Company t o  provide  manifold  Works  conversion  D i s t r i c t Drainage Board.  became commonly used. one  s u c c e s s f u l and l e d to the  mixing.  Instead  of  being  directly  mixed w i t h a i r i n the i n t a k e  i n j e c t i o n through  T h i s f l u t t e r v a l v e a c t e d as n o n - r e t u r n  a 'flutter'  v a l v e t o prevent  valve. pressure  p u l s a t i o n s or e x p l o s i o n s p a s s i n g back i n t o the gas supply The studies engines. section.  literature of  of  the  dual-fuel  These  are  1950's  operation  discussed  reveals on  in  some  fundamental  direct-injection detail  in  the  pipes.  diesel  following  12  2.2  Review of Research An  extensive  summary  of  combustion r e s e a r c h i s p r o v i d e d and  Karim(l982).  been  reviewed  by  considerable experience  Both  i n review papers by  Karim(l980)  r e s e a r c h r e s u l t s and a p p l i c a t i o n s have  0'Neal(1982).  amount and  the r e s u l t s of d u a l - f u e l d i e s e l  of  The  information  combustion  literature concerning  processes  of  contains the  a  operating  dual-fuel  diesel  operation  though t h i s i s r e s t r i c t e d t o d i r e c t - i n j e c t i o n engines  only.  research experiences  The  are d i s c u s s e d i n t h i s s e c t i o n i n  c h r o n o l o g i c a l order as i n d i c a t e d i n T a b l e 2.1 main f e a t u r e s of each p r o j e c t .  The  which mentions the  review here i s r e s t r i c t e d t o  s t u d i e s which i n v o l v e methane-based gases. The  importance of g a s - a i r  operation  was  studied  e x p e r i m e n t s w i t h a CFR" 21:1,  selected  by  mixture  Elliott  strength  &  in  dual-fuel  Davis(l95l).  In t h e i r  d i e s e l engine a t a compression r a t i o  pilot  diesel  rates  were  held  constant  determine the e f f e c t of the c o n c e n t r a t i o n of n a t u r a l gas methane,  10.6%  experiments  other  showed  hydrocarbons)  that  in  the  when the g a s - a i r m i x t u r e  below a c e r t a i n l i m i t , the p r o p o r t i o n of gas with  diesel  fuel-air  r a t i o and  f l a m m a b i l i t y (which  (88.9% Their was  increased  strength.  i s below the lower  i s commonly d e f i n e d as the  to  strength  reacting  gas-air mixture  found t h a t i f the c o n c e n t r a t i o n of gas of  intake.  of  They limit  concentration  *CFR ( C o o p e r a t i v e F u e l Research) e n g i n e : single-cylinder engine, with 3.25 i n . (82.5 mm) bore and 4.5 i n . (114 mm) s t r o k e , manufactured by the Waukeska Engine Co. of Waukeska, Wis., the s t a n d a r d engine used f o r d e t o n a t i o n measurement and g e n e r a l l y f o r d e t o n a t i o n r e s e a r c h .  AUTHOR  DATE  Elliot & Davis  1951  Lewis  1954  S i m o n s on  1954  S i m o n s on  1955  Moore & Mitchell  Mi t c h e l l & Wh i t e h o u s e  1955  1955  GASEOUS  ENGINE CFR diesel c r . 16: 1,  21: 1  n a t u r a l gas methane other hydrocarbon  single-cylinder direct-injection c r . 14.7:1 b o r e 105mm s t r o k e 152mm  s l u d g e gas me t h a n e nitrgen carbon dioxide  single-cylinder direct-injection c r . 14.7:1  me t h a n e  single-cylinder direct-injection c r . 14.7:1 b o r e 105mm s t r o k e 152mm single-cylinder direct-injection bore 105mm s t r o k e 152mm f our-cylinder direct-injection c r. 13.5:1 bore 254mm s t r o k e 30 5mm  MAIN  FUEL  88.9% 10.6%  8 6.8% 4.5%  l o w e r l i m i t o f f lammab i 1 i ty, d e p e n d e n c e o f amount o f g a s r e a c t e d on g a s - a i r m i x t u r e s t r e n g t h and d i e s e l fuelair ratio. effect of intake a i r r e s t r i c t i o n and i n t a k e a i r preheating on e f f i c i e n c y .  5.5% e f f e c t of intake a i r preh e a t i n g on r e a c t i o n s o f gaseous charge.  e f f e c t of intake a i r preheating, intake a i r r e s t r i c t i o n , and v a r y i n g injecti o n t i m i n g on e f f i c i e n c y .  methane  e f f e c t of intake a i r preheating, intake a i r restri c t i o n , and v a r y i n g injecti o n t i m i n g on e f f i c i e n c y .  me t h a n e  sludge gas methane nitrogen carbon dioxide  FINDINGS  87.9% 4.4% 5.5%  e f f e c t of intake a i r r e s t r i c t i o n on e f f i c i e n c y  Felt & Steele  Kar im, Klat, & Moore  K a r im & Kahn  1962  1966/67  1968  single-cylinder direct-injection c r . 16.2:1  n a t u r a l gas me t h a n e nitrogen other hydrocarbon  single-cylinder direct-injection c r . 14.2:1 bore 108mm s t r o k e 152mm  me t h a n e  single-cylinder direct-injection bore 105mm s t r o k e 152mm  *  Table  2.1 - Summary  8 7.1% 7 . 1%  p r o b l e m s w i t h l o s s o f combustion c o n t r o l , e f f e c t of additives on k n o c k - l i m i t e d power.  5.1%  9 7.8%  determination of l i m i t e d powe r .  knock-  me t h a n e  heat r e l e a s e analysis, two-phased combustion.  gas c o m p o s i t i o n based  on v o l u m e  o f Past  Experimental  Work  15  of  gaseous  fuel-air  fuel  i n the i n t a k e a i r at which the minimum l i q u i d  ratio  yields  consistent  and  close-to-complete  combustion) the gas does n o t . r e a c t c o m p l e t e l y w i t h oxygen u n l e s s it  is  i n , or  temperature  immediately  region.  stoichiometric  In  gas-air  adjacent  the  to,  absence  mixture  of  does  an i n f l a m e d or h i g h pilot  diesel,  not appear t o r e a c t t o a  s i g n i f i c a n t e x t e n t ; the exhaust gas a n a l y s i s shows the  a  no  sign  of  presence of carbon d i o x i d e , carbon monoxide, or a l d e h y d e s .  T h e r e f o r e , u n l e s s the n a t u r a l gas i s  in  a  comparatively  high  temperature r e g i o n , i t i s u n l i k e l y t h a t the gas would r e a c t when its  c o n c e n t r a t i o n i s lower than the lower l i m i t  concentration.  The t e s t s of E l l i o t and D a v i s i n s e v e r a l d i e s e l  engines  showed  t h a t the lower l i m i t of f l a m m a b i l i t y of n a t u r a l gas i n a i r under c o n d i t i o n s e x i s t i n g at the end of compression i s a p p r o x i m a t e l y 4 to  5 percent  by  volume.  The  corresponding  ratio  for  the  s t o i c h i o m e t r i c m i x t u r e s t r e n g t h was 9.1% by volume. The experiments operations  with  by  weak  volume).  Lewis used  dioxide,  4.5%  Lewis(l954) gas-air  sludge  were  mixture  gas(86.6%  may  the  direct-  The  of  14.7:1  and  engine  lower l i m i t of f l a m m a b i l i t y i n h i s work by volume.  This i s  somewhat  higher  r e s u l t of e a r l i e r work by E l l i o t and D a v i s ( l 9 5 l ) , and  be due t o the  nitrogen  (below 8% by  n i t r o g e n by volume) i n a s i n g l e c y l i n d e r  of 1000 rpm.  methane,  on  carbon  was shown t o be about 6.2% than  strength  mainly  5.45%  i n j e c t i o n engine w i t h compression r a t i o speed  focused  in  the  high  c o n c e n t r a t i o n of  s l u d g e gas used by L e w i s .  carbon  dioxide  and  The experiments by  Lewis showed t h a t when the g a s - a i r m i x t u r e s t r e n g t h i s below the flammability  limit,  restricting  intake  air  results  in  16  significant  increase  in  the  increase in i g n i t i o n delay. found  to  increase  the  amount  of  gas  reacted  P r e h e a t i n g of i n t a k e a i r  strength).  gas-air mixture The  ignition  r e l a t i o n to g a s - a i r m i x t u r e ignition  point  the p o i n t of F i g u r e 2.1  shows  Increase  i n longer  mixture  delay.  The  pressure  l b / h (0.188 kg/h,  g a s - a i r mixture in  strength  70% at  pilot  also  rise  due  to  in g a s - a i r mixture  combustion. pilot  diesel full  strength resulted Beyond  the  s t r e n g t h of about 4% by volume, f u r t h e r i n c r e a s e showed  sharp  reduction  v a r i a t i o n i n i g n i t i o n delay  i n the  f o r the range of  about 3 deg.  i n t a k e charge temperature of a  by Simonson(1954).  ignition mixture  CA.  e f f e c t on combustion c h a r a c t e r i s t i c s of g a s - a i r  charge  temperatures  mixture  strength ranging  exhaust  The  t r a c e as  mixture  motored-engine  ranging  from 241  from 0 t o 5% by  a n a l y s i s of c o n s t a n t - s p e e d  that increase in  intake  was  H i s e x p e r i m e n t s were performed w i t h  methane i n a d i r e c t - i n j e c t i o n s i n g l e - c y l i n d e r engine f o r  from  1.0%  diesel in  studied.  i g n i t i o n d e l a y of p i l o t d i e s e l .  strength  s t r e n g t h and studied  was  (95%  10% of the s t r a i g h t d i e s e l  s t r e n g t h of 0 to 8% by volume was The  of  the r e s u l t s o b t a i n e d at c o n s t a n t  fuel rate).  initially  s t r e n g t h ,and  delay  charge  achieved  i d e n t i f i e d from the p r e s s u r e - t i m e  significant  r a t e of 0.415 load  was  also  W i t h p r e h e a t i n g of the i n t a k e  t o 225 deg.C s u b s t a n t i a l l y complete combustion was  mixture  was  in  amount of gas r e a c t e d , but r e s u l t e d i n  decreased i g n i t i o n delay.  of gas r e a c t e d a t 4.5%  and  charge  f a v o u r a b l e c o n d i t i o n s f o r flame  t o 325 deg.C and volume.  The  intake gas-air results  motored t e s t s r e v e a l e d  temperature propagation.  results  in  more  13 speed  < O  1000 r p m  12  pilot diesel 0.415 Ib/hr  o  LU Q  >-  < _J  LU  11  gas  10  methane  Q  O  8 7  0  GAS  2  IN  3  4  ENGINE  5 INTAKE  6 BY  7  8  (%)  VOLUME (Lewis,  Figure 2.1 - Effect on  of G a s - A i r M i x t u r e  Ignition  Delay  Strength  1954)  18  Further included  work by Simonson(1955),  with fired-engine  s t u d i e s of t h e e f f e c t s of a i r r e s t r i c t i o n , and changes  i n p i l o t d i e s e l r a t e and i n j e c t i o n t i m i n g . engine  ( t h e same  engine  A  direct-injection  as t h e one used by L e w i s ( 1 9 5 4 ) ) w i t h  compression r a t i o of 14.7:1 was used w i t h methane a t of  operation  1000  rpm.  Preheating  the  speed  of i n t a k e charge t o 157 deg.C showed  improvements of 20 t o 30% i n f u e l consumption a t p a r t l o a d s (1060 p s i or 70-410 kPa i n brake pilot  diesel  diesel f u l l advancing  rate  consisting  load operation. of  mean  injection  range.  pressure)  With t h e same  timing  by  pilot  diesel  6 deg. C A .  by 10 t o 17% i n the  d i e s e l r a t e gave s i g n i f i c a n t improvements i n f u e l  injection  timing.  115 p s i (793 kPa) r e v e a l e d by  8  same  deg. C A .  at  part  consumption. advanced  brake mean e f f e c t i v e p r e s s u r e of  t h a t advancing t h e  increased  in  in pilot  was observed t o i n c r e a s e w i t h  Tests  rate,  resulted  Both i n t a k e a i r r e s t r i c t i o n and i n c r e a s e  Maximum c y l i n d e r p r e s s u r e  with  8.5% of d i e s e l r a t e of s t r a i g h t  improvement of f u e l consumption load  effective  injection  timing  t h e maximum c y l i n d e r p r e s s u r e  from  1000 t o 1250psi (7 t o 8.7 MPa).  E a r l y i g n i t i o n and r a p i d  of  t o set a l i m i t t o the extent t o  pressure  r i s e were r e p o r t e d  which improved performance  can  injection  a  timing.  With  be  obtained  pilot  diesel  by  advancing  injection  0.8 l b / h (0.36 kg/h, 16% of s t r a i g h t d i e s e l f u l l  rates  the  rate  load fuel  of  rate)  at 24 deg BTDC (10 deg advance) combustion was rough even a t the brake mean e f f e c t i v e p r e s s u r e Experiments consumption  were  leading done  to  of 30 p s i (210 k P a ) . improvement  i n part-load  by Moore and M i t c h e l l ( 1 9 5 5 ) .  c y l i n d e r d i r e c t - i n j e c t i o n engine w i t h 4.125 i n  fuel  A single-  (105.4 mm)  bore  19  and  6.00 i n (152 mm) s t r o k e was used a t the speed of 1000 rpm.  Tests c a r r i e d restriction  out  with  sludge  gas  on  , i n t a k e charge p r e h e a t i n g , and a d v a n c i n g  t i m i n g showed r e s u l t s s i m i l a r t o those Simonson (1 955) .  of  past  work  they  the above  concluded  temperature i s the o n l y p r a c t i c a l way  that of  of a i r injection  the experiments  As much as 20% improvement i n f u e l  was r e p o r t e d i n each s e p a r a t e t e s t of reviewing  the e f f e c t s  by  consumpti'on  methods.  In  r a i s i n g the i n t a k e  extending  the  lower  l i m i t of f l a m m a b i l i t y . Work  on  a  Whitehouse(1955). 10 i n  (254 mm)  large  engine  was  A four-cylinder  described  direct-injection  optimum  conditions  4.4%  a i r restriction  pressure  showed  of  or  remained  to  determine  and e f f i c i e n c y . methane,  5.5%  The  carbon  T e s t s on the  effect  a c o n s i d e r a b l e improvement i n f u e l reported  at  t h e brake  20 p s i (140 kPa, 26% of f u l l  was a l s o found t h a t w i t h optimum temperature  (87.9%  load f u e l rate.  consumption: 46% improvement was effective  of  The p i l o t d i e s e l r a t e was a c o n s t a n t  nitrogen).  6% of s t r a i g h t d i e s e l f u l l of  600 rpm  for r e l i a b i l i t y  gaseous f u e l used was s l u d g e gas dioxide,  engine  bore and 12 i n (305 mm) s t r o k e w i t h compression  r a t i o of 13.5:1 was used a t the speed of the  by M i t c h e l l and  a i r restriction  load).  the  mean It  exhaust  a p p r o x i m a t e l y c o n s t a n t ( w i t h i n ± 50 deg.F  30 deg.C) a t a l l l o a d s . E x p e r i m e n t s made  knock-limited  maximum  by  Felt  power  knock q u a l i t y of t h e p r i m a r y injection  and  Steele(1962)  showed  that  i s d i r e c t l y r e l a t e d t o the a n t i fuel.  A  three-cylinder  direct-  engine w i t h compression r a t i o of 16.2:1 was used w i t h  20  pilot  diesel  rate  of  1.65  l b / h (0.74 kg/h, 12.8% of s t r a i g h t  d i e s e l f u l l load f u e l r a t e ) . were  found  to  be  q u a l i t y of the propane  and  stream.  With  (100,000 Btu  alkyl  fuel.  A  mixture  tetramethyllead addition  or  of  was  (87.1%  consisting  95%  of  lead  per  therm  operation  with  natural  methane, 5.1% o t h e r h y d r o c a r b o n s , 7.1% n i t r o g e n ) by  high-frequency pressure-time observation  The knock was d e s c r i b e d  combustion trace.  loss',  The  which  knock  was  was  as  'audible  visible  described  on  from  the the  of the shape of the p r e s s u r e - t i m e t r a c e as 'end-gas  knock': the knock a r i s i n g from the a u t o i g n i t i o n of of  of  106,000 kJ) of n a t u r a l gas, i t was p o s s i b l e t o  28 percent w i t h o u t knock.  ahead  compounds  b l e d i n t o the i n t a k e a i r  5.5-6.0 gm  enhance the maximum power of d u a l - f u e l gas  anti-knock  q u i t e e f f e c t i v e i n enhancing the a n t i - k n o c k  primary 5%  Lead  the  flame  front.  the  end-gas  I t i s the type of knock which  may  occur i n s p a r k - i g n i t i o n e n g i n e s . The rate  influences o f f u e l - a i r mixture strength,  and  intake  studied in d e t a i l cylinder  direct  air by  temperature Karim  injection  et  with  14.2:1 and 97.8% methane as the gaseous observed  to  be  associated  typical  F i g u r e 2.2.  shape The  of  with  a  compression fuel.  The  singler a t i o of  knock  was  w i t h a sharp change i n the running  regime of the engine and accompanied The  diesel  on k n o c k - l i m i t e d power were  al.(1966/67)  engine  pilot  the  knock-limited  by l o u d l y  pressure power,  audible  diagram which  is is  sound. shown  shown  in in  F i g u r e 2.3, was observed t o decrease w i t h i n c r e a s e i n the i n t a k e air  temperature  and/or  p i l o t quantity.  I t was  found t h a t the  knocking occured o n l y i n a c e r t a i n range of m i x t u r e s t r e n g t h ; i f  21  - 6 0  - 3 0  T D C  3  0  6  0  (Karim et al.,1966/67) Figure  2.2 - T y p i c a l P r e s s u r e - T i m e Trace of Non-knocking and Knocking O p e r a t i o n w i t h Methane as Gaseous F u e l  Figure  2.3 - V a r i a t i o n of Power Output w i t h the Overall Mixture Strength for D i f f e r e n t Intake Temperatures  23  the  engine was o p e r a t e d on e i t h e r s i d e of t h a t range of m i x t u r e  s t r e n g t h , knock c o u l d be a v o i d e d .  The r e g i o n of knocking  the l e a n s i d e of s t o i c h i o m e t r i c m i x t u r e  strength.  was on  The e f f e c t of  the c e t a n e number of t h e p i l o t d i e s e l on t h e onset of knock  was  found t o be s m a l l . Karim attempt  and  to  analysis  Kahn(l968) employed heat r e l e a s e a n a l y s i s i n an  interpret  with  a  the combustion  single-cylinder  methane as the gaseous combustion is mainly  generally  fuel,  with  part  a s s o c i a t e d mainly  they  concluded  The f i r s t  the  gaseous  w i t h the gaseous  lean operation  supported previous  quality.  low  of  fuel.  fuel  and  load  experimental operation  r e l e a s e of t h e f i r s t phase.  burning  The  fuel  second  depends  is  on i t s  evidences  i s due mainly  supplement  that t o the  effectively  the  The a n a l y s i s of the o p e r a t i o n  w i t h knock i n d i c a t e d t h a t t h e knock was m a i n l y simultaneous  the p i l o t  The heat r e l e a s e a n a l y s i s of very  i n a b i l i t y of the gaseous charge t o  rapid  engine and  undergoes two d i s t i n c t phases.  of  at  the  dual-fuel  and  combustion  From  that  concentration  heat  direct-injection  a s s o c i a t e d w i t h t h e consumption  together  poor  processes.  associated  of t h e p i l o t d i e s e l t o g e t h e r  with with a  s u b s t a n t i a l f r a c t i o n of t h e gaseous charge. Study compression  of  knock-limited  ratio  and  paper by 0 ' N e a l ( 1 9 8 2 ) . rapidly  engine  maximum  power  in relation  to  speed i s i n c l u d e d i n the review  The k n o c k - l i m i t e d power  as t h e compression r a t i o i s reduced.  increases  very  The t r e n d f o r the  k n o c k - l i m i t e d bmep i s t o i n c r e a s e w i t h engine speed.  As  engine  speed i n c r e a s e s , l e s s time i s a v a i l a b l e f o r t h e end-gas t o reach  24  the temperature f o r a u t o i g n i t i o n , and  thus the onset of knock i s  suppressed. In  summary,  the  literature  reveals  that  r e s e a r c h has been done on d u a l - f u e l o p e r a t i o n w i t h injection  type  of  diesel  engine.  s u f f e r s from weak g a s - a i r m i x t u r e gas e s c a p i n g  w i t h the exhaust.  At  considerable the  direct-  low l o a d s , combustion  s t r e n g t h r e s u l t i n g i n unburned  F i g . 2.4  shows  typical  thermal  e f f i c i e n c i e s of d u a l - f u e l o p e r a t i o n w i t h d i r e c t - i n j e c t i o n engines. diesel  R e s t r i c t i n g or p r e h e a t i n g flow  intake a i r , increasing p i l o t  r a t e , and a d v a n c i n g the i n j e c t i o n t i m i n g have been  shown to be e f f e c t i v e f o r improving loads.  diesel  Maximum  the f u e l consumption at  power output of h i g h l o a d o p e r a t i o n  is limited  by the occurence of knock, which appears t o be of the same as  in  s p a r k - i g n i t i o n engines.  Adding  lead a l k y l  compounds or c o o l i n g the i n t a k e a i r were shown t o in  improving  knock-limited  maximum  however, seems s i l e n t on d u a l - f u e l prechamber type of d i e s e l  engine.  power.  diesel  be  The  operation  low  kind  anti-knock effective literature, with  the  o  Brake  Figure  2.4  - Typical  Thermal  Mean  Efficiencies  Effective  of  Pressure  Dual-Fuel  and  Straight  (kPa)  Diesel  Operation  26 CH.III Apparatus  The  arrangement  F i g . 3.1.  were  The  exhaust  was  and  a  coupled  various  instruments The  entering  the  shown  The  exhaust  in  electromagnetic transducer  processed  The  data  with  a  of a i r , n a t u r a l gas,  and  N a t u r a l gas i s mixed  the t u r b o c h a r g e r .  e x i t i n g from the t u r b o c h a r g e r e n t e r s intake stroke.  an  were  flow diagram  gas i s p r o v i d e d i n F i g . 3.2. to  to  is  NEFF/620 data a q u i s i t i o n u n i t .  computer.  prior  instruments  s i g n a l s from the c y l i n d e r p r e s s u r e by  from  11/34  apparatus  engine  collected  obtained  air  of  The  dynamometer.  PDP  and I n s t r u m e n t a t i o n  the  The  with  g a s - a i r mixture  cylinder  during  gas from the c y l i n d e r passes  the  through  t u r b i n e s i d e of the t u r b o c h a r g e r , and then e n t e r s a m u f f l e r  b e f o r e d i s c h a r g i n g t o open a i r .  3.1  Engine and Test  Bed  Engine A c a t e r p i l l a r 3304 f o u r - c y l i n d e r electromagnetic engine  speed  experiments. manufacturer pressure. a  dynamometer was  adjusted  Full  load  as  124 p s i  The engine  turbocharger.  The  at  was  engine  used  to this  (856 kPa)  in  1600 speed in  coupled this  rpm was  with  project.  throughout  an The the  s p e c i f i e d by the  brake  mean  effective  i s of prechamber type and i s equipped s p e c i f i c a t i o n of the engine  with  i s provided i n  diesel load control  =C3T1  diesel flow rate^  dynamometer  CAT.  3 3 0 4  7 TT  loaa cell turbocharger  intake pressure^  •pressure transducer  •I  [toothed wheel  1  charge amp. N E F F data acqufeit unit  ^-optical pickup PDP 11 minicomputer  gas mixer  gas flow rate^A gas valve —^  air. . ,. restriction  T air  Figure 3.1  air  t exhaust  terminal  flow rate  - Layout of Apparatus and I n s t r u m e n t a t i o n  printer  exhaust  F i g u r e 3.2 - Flow Diagram of A i r , F u e l , and Exhaust Gas  2 9  BORE  1 2 . 1  cm  ( 4 . 7 5  in. )  STROKE  1 5 . 2  cm  ( 6 . 0  in.)  DISPLACEMENT  6 9 7 0  COMPRESSION RATIO  1 7 . 5  NUMBER OF CYLINDERS MAXIMUM POWER  c  m  :  3  ( 4 2 5  cu.in.)  (  hp)  1  4  9 3 . 2  at  kW 2 0 0 0  1 2 5  rpm  TYPE  prechamber  ASPIRATION  turbo-charged  T a b l e 3 . 1 - Engine  Specification  30  SCALE 2.5:1  A  -  PRECHAMBER  B  -  MAIN  Figure  3.3 - S h a p e  CHAMBER  of Combustion  Chambers  31  Table 3.1. The volume of the prechamber i s 27 percent total  volume  cross-section  when of  of t h e  t h e p i s t o n i s a t the t o p dead c e n t e r . prechamber  and main  chamber  The  i s shown i n  F i g . 3.3.  D i e s e l I n j e c t i o n System The engine was equipped w i t h a s l e e v e m e t e r i n g type of f u e l system.  F i g . 3.4  shows  components of the s l e e v e shown  the l a y o u t metering  of the system.  diesel-injection  pump a r e  i n F i g . 3.5. The p l u n g e r i s moved up and down i n s i d e t h e  b a r r e l by the a c t i o n of t h e pump camshaft. effective  stroke  i n j e c t i o n events. governor  of  the p l u n g e r  and  F i g . 3.6  shows t h e  t h e sequence  The s l e e v e m e t e r i n g system  uses  of t h e  centrifugal  f l y w e i g h t s (shown i n F i g . 3.7) i n o r d e r t o prevent any  change i n engine speed due t o the v a r i a t i o n i n l o a d . the  The main  governor  control  Thus  once  i s s e t a t c e r t a i n p o s i t i o n i n t h e rack  s e t t i n g , t h e engine speed  i s maintained constant  p o s s i b l e change i n l o a d .  F i g . 3.8 shows t h e s i n g l e h o l e d i e s e l -  injection  nozzle  adjusted  to  used i n the e n g i n e .  desired  angle  manual(NO.SER7053-01, pp80).  r e g a r d l e s s of  The i n j e c t i o n t i m i n g was  according  to  the  service  32  F i g u r e 3.4 - S l e e v e M e t e r i n g  F u e l System  Roller Follower  F i g u r e 3.5 - F u e l I n j e c t i o n Pump and  Housing  33  SPILL PORT  PORT  1— H L LINl*  J-BEC::.  EFFECTIVE STROKE  INJECTION  3 • CO*.7;SJE INJECTION  F i g u r e 3.6 - Sequence of I n j e c t i o n  Events  GOVERNOR CONTROL SHAFT  BELLCRANK SHAFT • ELLCRANK-  GOVERNOR CONTROL LEVER  CARRIER  SPRING SEATS  THRUST GOVERNOR DRIVE SHAFT  COLLAR GOVERNOR FLYWEIGHTS  GOVERNOR SPRING  COVER OF G O V E R N O R FLYWEIGHTS  F i g u r e 3.7 - Governor Components of S l e e v e M e t e r i n g  Figure  3.8  -  Fuel  Injection  Nozzle  35  Turbocharger The  engine  manufactured  was  equipped  by A i R e s e a r c h .  w i t h a T1210 model t u r b o c h a r g e r  A cutaway view of the  turbocharger  i s shown i n F i g . 3.9.  Dynamometer The  engine  was  c o u p l e d t o an e l e c t r o m a g n e t i c dynamometer  (General E l e c t r i c , model 1G136).  The a b s o r p t i o n c a p a c i t y of the  dynamometer was 200 horse power (150 kW).  Gas-mixer In o r d e r t o i n t r o d u c e the n a t u r a l gas, a was  installed  on  upstream  simple  gas-mixer  of the i n l e t t o the t u r b o c h a r g e r .  F i g . 3.10 shows the gas-mixer.  Intake A i r R e s t r i c t i o n A s i m p l e ' b u t t e r f l y ' type of v a l v e was i n s t a l l e d gas-mixer  t o c o n t r o l the amount of a i r i n t a k e .  near  the  Figure  3.9  - Turbocharger  Cutaway  View  37  38  3.2 I n s t r u m e n t a t i o n  Torque The  torque  a p p l i e d by t h e engine s h a f t t o dynamometer was  o b t a i n e d by p l a c i n g a s t r a i n model 1420-4F)  on  the  gage  dynamometer  a l l o w a b l e l o a d s p e c i f i e d by bridge  a m p l i f i e r meter  load  cell  housing.  t h e manufacturer  by  placing  various  weights  dynamometer h o u s i n g and r e a d i n g amplifier  meter.  The  p r o v i d e d i n Appendix A. the  The  was  maximum  500 l b .  A  ( E l l i s A s s o c i a t e s , model BAM-1) was used  to a m p l i f y the response from t h e l o a d c e l l . calibrated  (Interface Inc.,  The l o a d on  the v o l t a g e  calibration  cell  the arm from  was  of the  the b r i d g e  curve f o r the l o a d c e l l i s  The r e l a t i o n between,  the  response  l o a d c e l l and the a p p l i e d weight was very n e a r l y  of  linear.  Cylinder Pressure The  no. 1  cylinder  was  e l e c t r i c pressure transducer was  (model 8QP500c).  transducer.  F i g . 3.11 shows  the l o c a t i o n  The  transducer  of  the mounted  The s i g n a l from t h e t r a n s d u c e r was t r a n s m i t t e d by a  n o i s e c a b l e t o a charge a m p l i f i e r  then t o a d a t a a c q u i s i t i o n system. NEFF,  w i t h an AVL p i e z o -  c o o l e d w i t h water and mounted i n a s t e e l s l e e v e through the  c y l i n d e r head.  low  instrumented  System 620, analogue  to  ( K i s t l e r , model 5004) and  The system digital  connected t o a PDP 11/34 minicomputer.  consisted  converter A computer  of  which program  a  was was  S C A L E  F i g u r e 3 . 1 1 - Mounting of C y l i n d e r P r e s s u r e Transducer  1.7:1  40  written  (see  Appendix C)  to  sample  the  pressure  i n t e r v a l s of one degree crank a n g l e , a l o n g w i t h center  signal,  drawn  from  an  optical  t o o t h e d wheel at the f r o n t of the engine. an  ensemble-averaged  50 c y c l e s were  value  of  pressure  f o r each degree of crank a n g l e .  then used t o compute i n d i c a t e d  to a n a l y z e apparent  energy  release.  2000 p s i  (14 MPa).  The  bottom  dead  sensor mounted on the The program  computed  c o l l e c t e d over 30 to The  averaged  values  mean e f f e c t i v e p r e s s u r e  and  The p r e s s u r e t r a n s d u c e r  was  c a l i b r a t e d u s i n g a dead-weight t e s t e r to  a  s i g n a l at  f o r a p r e s s u r e range of  calibration  0  curve i s p r o v i d e d i n  Appendix A.  A i r Flow Rate A l a m i n a r flow element (Meriam Instrument, model range  0-400SCFM) was  50MC2-4F,  used t o measure the a i r flow r a t e .  mounted between the a i r f i l t e r and t u r b o c h a r g e r . d r o p • a c r o s s the element was  The  I t was pressure  read i n i n c h e s of water on a water-  f i l l e d U-tube manometer and t r a n s l a t e d  to v o l u m e t r i c flow r a t e .  The c a l i b r a t i o n curve p r o v i d e d by the  element  manufacturer  is  shown i n Appendix A.  Gas Flow Rate The  natural  p r e s s u r e of 5 p s i . regulator  gas  was  drawn i n from the mains s u p p l y at a  The gas was  which reduced  then passed through  a  pressure  the p r e s s u r e t o a p r e s s u r e a few  inches  41  of water h i g h e r element was  than  pressure.  mounted t o measure the flow r a t e .  manometer and  laminar  read i n i n c h e s of water on a w a t e r - f i l l e d  U-tube  flow  rate.  The  then c o r r e c t e d f o r n a t u r a l gas by m u l t i p l y i n g t h e  intake  valve.  was  The  D i e s e l Flow  controlled  calibration  manufacturer  ratio  manually w i t h a t a p e r e d t y p e o f curve  i s shown i n Appendix  provided  of  by  the  gas  element  A.  range  0.05-5GPH)  (American  which m e a s u r e s c u m u l a t e d  f o r a time p e r i o d o f  to o b t a i n the v o l u m e t r i c f l o w r a t e of d i e s e l .  10  The  the f l o w meter was c o n f i r m e d by u s i n g a g r a d u a t e d  Turbocharger  Meter,  flow  t o 20  rate  minutes  accuracy  of  cylinder.  Inlet Pressure  a p r e c a u t i o n t o p r e v e n t the p o s s i b i l i t y o f t u r b o c h a r g e r  surge due t o e x c e s s i v e a i r r e s t r i c t i o n , the a i r p r e s s u r e at inlet  rate  Rate  was used w i t h a s t o p watch  As  flow  The a m o u n t o f g a s a d m i t t e d  A p o s i t i v e d i s p l a c e m e n t type of flow m e t e r model 1A,  0-15SCFM)  across  t r a n s l a t e d to volumetric  The  flow  pressure drop  v i s c o s i t i e s f o r a i r and n a t u r a l gas. to  A  (Meriam I n s t r u m e n t , model 50MH10-1.25NT, r a n g e  the element was  was  atmospheric  of  compressor  the  s i d e of the t u r b o c h a r g e r was measured f o r  each change of a i r flow r a t e .  A water-filled  U-tube  was used.  The  l i m i t i n g measure of the compressor  specified  by  the  engine  manufacturer  manometer  i n l e t pressure  was 24 i n c h e s of water  42  below the a t m o s p h e r i c p r e s s u r e .  Intake A i r Pressure In o r d e r t o measure turbocharger,  a  the  bourdon-tube  intake  a i r pressure  pressure)  was  the  type of p r e s s u r e gage (Marquette,  model 41-123, range 30 i n c h e s of water vaccuam t o atmospheric  after  15 p s i above  mounted on the i n t a k e m a n i f o l d near  no. 4 c y l i n d e r .  Engine Speed The engine speed was measured by a hand d i g i t a l (Shimpo,  model  tachometer  DT-205) which sends out a c o n t i n u o u s l i g h t beam  and counts the p u l s e s r e f l e c t e d o f f a p i e c e of a t t a c h e d on the engine  shaft.  reflective  tape  43  3.3 F u e l  Diesel The  diesel  fuel  following typical  In  throughout the experiments had the  properties:  API g r a v i t y  -  31  specific gravity  -  0.871  lower h e a t i n g v a l u e  -  45,263 k j / k g  the  analysis  stoichiometric the  used  of  energy  release  f u e l - a i r r a t i o dodecane  and (CiaH^)  r e p r e s e n t i n g hydrocarbon f o r the d i e s e l  computation  of  was assumed t o be  fuel.  N a t u r a l Gas The n a t u r a l gas used i n the experiments had  the  following  propert i e s : density  -  0.766 kg/m at  101.3 kPa, 25 deg.  viscosity  -  3  C  108.96 m i c r o p o i s e at 21.1 deg. C  lower h e a t i n g v a l u e A  typical  T a b l e 3.2.  -  48,558 kJ/kg  c o m p o s i t i o n of the n a t u r a l gas used here i s g i v e n i n  44  COMPOSITION methane  RELATIVE VOLUME (%) 94.00  ethane  3.30  propane  1 .00  i so-butane  0.15  n-butane  0.20  i so-pentane  0.02  n-pentane  0.02  ni trogen  1 .00  carbon d i o x i d e  0.30  hexane  0.01  T a b l e 3.2 - T y p i c a l C o m p o s i t i o n of t h e N a t u r a l Gas Used  45  3.4  Data  Process The m e a s u r e m e n t s  experiment of  the  were  fed  into  the  from  various  instruments  PDP 11/34 c o m p u t e r  for  for  each  computation  following:  .  power  .  thermal  .  volumetric  .  proportion based  .  obtained  output  efficiency of  diesel  on h e a t i n g  gas-air,  A typical  efficiency  output  listing  of  the  included  in Appendix  the  computer II.  total  fuel  input  values  diesel-air, from  to  total  data  fuel-air  process  is  program used  ratio shown  for  the  in Table  3.3.  computations  A is  46  engine  speed  1 601  rpm  air  flow r a t e  170  c u.f t/m i n  d i e s e l flow r a t e  1 .82  1/hr  gas  6.32  c u.f t/m i n  flow r a t e  f u e l consumption r a t e  11,683 BTU/hr-hp  power output  35.6  brake mean e f f e c t i v e  p r e s s u r e 4 1.4  hp ps i  thermal  efficiency  21.8  %  volumetric  efficiency  86.3  %  15.5  %  d i e s e l input p r o p o r t i o n gas-air  equivalence  ratio  0.365  d i e s e l - a i r equivalence  ratio  0.068  fuel-air equivalence (total fuel)  ratio  0.433  Table 3.3 - T y p i c a l Output of Computer Program f o r Data Processing  47  CH.  IV.  4.1  F u e l Consumption  4.1.1  Experimental  Results  F u e l Consumption w i t h Unmodified Engine Tests  were  consumption rate.  The  rate  with  engine  experiments. constant  carried  to  study  the  change  in  was  set  at  1600  rpm  for  flow  all  the  i n j e c t i o n t i m i n g of the d i e s e l f u e l remained  degrees b e f o r e top dead c e n t r e .  T e s t s always s t a r t e d from s t r a i g h t d i e s e l o p e r a t i o n . the engine was  fuel  v a r i a t i o n i n l o a d and p i l o t d i e s e l  speed  The  a t 12.3  out  running  on  100 percent  While  d i e s e l f u e l , the speed  a d j u s t e d w i t h the d i e s e l f u e l governor rack s e t t i n g t o 1600 and  the l o a d t o the p r e d e t e r m i n e d s e t t i n g .  The  gas  g r a d u a l l y added by opening the gas c o n t r o l v a l v e . of  gas  was  increased,  In F i g . 4.1, heating  value  brake  input.  region  where  The  reduced t o  thermal  efficiencies  based  on  lower  o p e r a t i o n was  erratic  operation diesel with  pressure-time paths  of  diesel  to  total  shaded a r e a on the l e f t c o r r e s p o n d s t o the  stable pilot  interpolated  then  are p l o t t e d a g a i n s t the f r a c t i o n a l d i e s e l energy  insufficient  cylinder  was  rpm.  i n p u t , which i s here d e f i n e d as the r a t i o energy  rpm,  As the amount  the flow of d i e s e l f u e l was  m a i n t a i n the speed at 1600  was  of  flow  is  rate.  misfired trace  constant  not  possible  because  In  r e g i o n , the  cycles  on pilot  the  this  observed  of  on  the  oscilloscope.  The  diesel  operation  are  Brake  Thermal Efficiency  8fr  (%)  49  indicated  by  the  Chapter I I I , the controlled  dotted diesel  lines.  As  injection  previously described i n  rate  of  respond  maintain  engine  was  by two mechanisms - the governor rack s e t t i n g , which  i s a d j u s t e d m a n u a l l y , and the c e n t r i f u g a l which  the  to  governor  flyweights,  any s m a l l change i n a p p l i e d l o a d i n order t o  a constant  speed.  Thus even though the rack s e t t i n g i s  h e l d f i x e d , a d d i t i o n of gas i n the i n t a k e would r e s u l t i n change in d i e s e l i n j e c t i o n rate.  For t h i s reason i t was  to c a r r y out t e s t s f o r c o n s t a n t It  is  seen  from  not  possible  p i l o t d i e s e l flow r a t e .  F i g . 4.1  that  the decrease of  thermal  e f f i c i e n c y due t o r e d u c t i o n of of p i l o t d i e s e l flow r a t e becomes s m a l l e r as the l o a d i n c r e a s e s . pressure  of  At  714 kPa (84 % of f u l l  e f f i c i e n c y i s l e s s than 1 percent diesel  energy  input  the  brake  mean  effective  l o a d ) , the change i n thermal  over the range  of 7 t o 100 p e r c e n t .  of  fractional  The e x t e n t  t o which  the f u e l consumption r a t e depends on the p i l o t d i e s e l f l o w for  i d l i n g operation  i s seen i n F i g . 4.2.  The i d l i n g  w i t h the f r a c t i o n a l d i e s e l energy i n p u t of 15 nearly  twice  rate  operation  percent  requires  as much energy i n p u t than t h a t of s t r a i g h t d i e s e l  operation. To o b t a i n another p i c t u r e of t h e r o l e of p i l o t d i e s e l  flow  r a t e i n d u a l - f u e l o p e r a t i o n , c a l c u l a t i o n s were made of i n d i c a t e d thermal  efficiencies.  based on t o t a l power overcome  the  The i n d i c a t e d thermal produced  frictional  closely correlated with  and the  (including pumping  efficiency,  the  power  being  used  to  l o s s e s ) , s h o u l d be more  effectiveness  of  the  combustion  p r o c e s s than the engine e f f i c i e n c y based on s h a f t power  output.  OS  51  This  assumption  i s c o n s i s t e n t w i t h the work of Simonson (1955)  i n which the measured v a l u e s the p r o p o r t i o n of s i m i l a r trends. used  in  gaseous  of i n d i c a t e d t h e r m a l e f f i c i e n c y and fuel  reacted  showed  qualitatively  Appendix B i n c l u d e s a d e s c r i p t i o n of the method  present  work  to  obtain  indicated  mean  effective  pressure. The i n d i c a t e d t h e r m a l e f f i c i e n c i e s plotted  in  F i g . 4.3.  . The  equivalence  the r a t i o of the required  for  mass  interpolated  and  The e f f i c i e n c i e s a r e shown as a f u n c t i o n  of the flow r a t e of p i l o t d i e s e l strength.  were  of  combustion  at  constant  gas-air  mixture  r a t i o 4>g of the gas was computed as the of  stoichiometric the  amount  of a i r  gas a l o n e t o the mass of the  a c t u a l amount of a i r drawn i n : i . e . 4>g =  s t o i c h i o m e t r i c a i r mass flow a c t u a l a i r mass flow  rate  rate  I t can be seen from F i g . 4.3 t h a t the p i l o t d i e s e l flow r a t e has a very air  s i g n i f i c a n t e f f e c t on the t h e r m a l e f f i c i e n c y at low  mixture  strength.  As the g a s - a i r m i x t u r e s t r e n g t h becomes  r i c h e r , the t h e r m a l e f f i c i e n c y becomes change i n p i l o t d i e s e l flow r a t e . 0.6,  less  sensitive  W i t h gas e q u i v a l e n c e  to  an i n c r e a s e of p i l o t d i e s e l flow r a t e from 1.4 t o 3.5 kg/h  efficiency.  If  i t i s assumed t h a t the measured v a l u e s  i n d i c a t e d thermal e f f i c i e n c i e s are l a r g e l y  would  the  r a t i o of  r e s u l t s i n l e s s than 1 p e r c e n t improvement i n i n d i c a t e d  amount  gas-  a  function  of gas burned, then the g a s - a i r e q u i v a l e n c e be  a  good  flammability  for  approximation this  for  particular  the  type  of  thermal of the of  the  r a t i o of 0.6  lower engine.  limit  of  The gas  53  equivalence ratio  r a t i o of 0.6 c o r r e s p o n d s t o the  of  about  the lower  4 percent.  gas-air  volumetric  T h i s approximate v a l u e  i s c l o s e to  i n f l a m m a b i l i t y l i m i t of 4 t o  5 percent  suggested  E l l i o t t and D a v i s ( l 9 5 l ) f o r a d i r e c t - i n j e c t i o n d i e s e l The d o t t e d l i n e s i n F i g . 4.3 i n d i c a t e load operation with v a r i a t i o n the  bottom  traces  a  constant  to 100 p e r c e n t fuelling left  at  The l i n e a t  t h e o p e r a t i o n a t i d l i n g , and the one a t the of f u l l  load.  Operating  p i l o t d i e s e l r a t e of 3.4 kg/h would  85 p e r c e n t  of  full  load.  correspond  20 p e r c e n t  d i e s e l f u e l l i n g a t i d l i n g and  diesel  The shaded area on the  i s the r e g i o n of u n s t a b l e o p e r a t i o n due t o m i s f i r i n g . F i g . 4.4 shows brake thermal  and d u a l - f u e l o p e r a t i o n s . the  engine.  the p a t h s of c o n s t a n t  in p i l o t diesel rate.  t o p the o p e r a t i o n a t about 84 percent with  by  fuel  consumption  i g n i t i o n engines. efficiency  improves  pressure peak.  for a  The s t r a i g h t d i e s e l  characteristics  As t h e l o a d i s  w h i l e the f r i c t i o n a l constant  because loss  fixed  further  One  of  the  increase  d e c l i n e , presumably due t o oxygen.  of  the  the  At  obtained  stable  engine the  load,  decreased  of compression  from  idling,  the  remains brake  relatively  mean e f f e c t i v e  efficiency the  reaches  curve  access  of  a  starts to fuel  to  of the d u a l - f u e l e f f i c i e n c y c u r v e s c o r r e s p o n d s t o  o p e r a t i o n w i t h t h e minimum p i l o t assure  shows  i n c r e a s e i n power output  thermal in  diesel  operation  typical  increased the  speed.  of about 700 kPa, With  efficiency for straight  operation  without  diesel  flow  misfiring.  from F i g . 4.1 by i n t e r p o l a t i o n .  rate This  The t h e r m a l  needed  to  curve  is  efficiency  of t h e d u a l - f u e l o p e r a t i o n a t p a r t l o a d i s s u b s t a n t i a l l y  lower  o  CD .  Figure  4 .4  -  Comparison Dual-Fuel  of and  Brake  Thermal  Straight  Efficiencies  Diesel  Operation  for  55  than  that  of  straight  diesel  operation.  At the brake mean  e f f e c t i v e p r e s s u r e of 850 kPa, which i s about load  at  1600  are same. higher  rpm, t h e thermal  E x t r a p o l a t i o n of the  loads  suggests  the  the  e f f i c i e n c i e s of both dual-fuel  trend  of  the  thermal  t o the homogeneous nature of g a s - a i r  o p e r a t i o n , which a l l o w s b e t t e r a c c e s s  full  operations  operation  s u r p a s s i n g t h a t of s t r a i g h t d i e s e l o p e r a t i o n . due  rated  curve  to  efficiency  T h i s t r e n d may be  mixture  in dual-fuel  of f u e l t o oxygen.  4 . 1 . 2 E f f e c t of R e s t r i c t i n g I n t a k e A i r Tests  to  determined  the  e f f e c t on thermal  e f f i c i e n c y of  r e s t r i c t i n g i n t a k e a i r were performed f o r s e v e r a l l o a d  settings  ranging  For each  from i d l i n g t o about 50 percent  of f u l l  load.  l o a d s e t t i n g , the r a t e of gas flow was c o n t r o l l e d flow The  so  that  r a t e of p i l o t d i e s e l would remain a p p r o x i m a t e l y a i r restriction  was  limited  by  the  constant.  minimum  allowable  p r e s s u r e of the a i r a t the i n l e t of the t u r b o c h a r g e r . restriction turbocharger, engine. to  of  a i r beyond the l i m i t r e s u l t e d i n s u r g i n g of the  either  by  of  the  of t h i s , the a i r - g a s flow r a t i o r e d u c t i o n had  be c o n f i n e d t o about  air,  Excessive  which i n t u r n caused v i o l e n t u n s t e a d i n e s s  Because  the  using  10 p e r c e n t .  reduction  of  g a t i n g or e l i m i n a t i n g t h e t u r b o c h a r g e r ,  would have i n c r e a s e d the m i x t u r e l i m i t of f l a m m a b i l i t y .  Sufficient  strength  to  near  the  Such an i n c r e a s e i n the m i x t u r e  may have l e d t o much improved f u e l consumption.  lower  strength  56  F i g . 4.5  shows- t h e e f f e c t  thermal  efficiency  mixture  strength  on t h e gas a l o n e . improvements  when  at  various  of  a i r r e s t r i c t i o n on brake  load  settings.  The  i s r e p r e s e n t e d by t h e e q u i v a l e n c e r a t i o based The t e s t s f o r a l l t h e l o a d a i r resriction  settings  i s imposed.  than  1  f o r about 10 percent a i r r e d u c t i o n .  4.1.3 E f f e c t of V a r y i n g I n j e c t i o n The the  exhibit  The i n c r e a s e i n  brake thermal e f f i c i e n c y however was f o r a l l cases l e s s percent  gas-air  Timing  i g n i t i o n d e l a y of p i l o t d i e s e l was s t u d i e d by o b s e r v i n g  averaged  cylinder  pressure  vs  d e t e r m i n i n g the p o i n t of the s t a r t of  crank  angle  ignition  trace.  (the point  In at  which combustion has proceeded f a r enough t o a f f e c t the p r e s s u r e n o t i c e a b l y ) , the e a r l i e s t s i g n i f i c a n t d e v i a t i o n of p r e s s u r e the by  expected close  compression  examination.  identification  curve near t o p dead c e n t r e was sought In  most  cases  this  method  of t h e p o i n t w i t h o u t d i f f i c u l t y .  a t y p i c a l pressure trace  from  and  identification  of  allowed  F i g . 4.6 shows the  apparent  p o i n t of i g n i t i o n . With  the  injection  t i m i n g f i x e d a t 12.3 degree BTDC, t h e  change i n i g n i t i o n d e l a y of p i l o t d i e s e l w i t h was  investigated at  addition  a range of l o a d s e t t i n g s .  the crank angle a t t h e s t a r t of i g n i t i o n w i t h t h e rate  varying  of  gas  F i g . 4.7 shows pilot  diesel  from 10-20 t o 100 p e r c e n t of t o t a l energy i n p u t .  For s t r a i g h t d i e s e l o p e r a t i o n a t low l o a d , t h e i g n i t i o n does not  p  CD*  IT)  1.5 kg/h  CD  571 kPa  u  -o  QJ IT) CN  278 kPQ  UJ <=»  — ' I  CM  cn  ro  QJ in  b^ep  a ro —  CD  1/5  o  CO  0.2  i—i—i—i—r 0.24 0.28  0.32  i—i—r  0.36  0.4  0.44  i—r  0.48  i — i — r  0.52  0.56  0.6  0.64  0.6B  Gas-Rir Mixture Strength (equivalence r a t i o based on gasJ  F i g u r e 4.5 - E f f e c t of Intake A i r R e s t r i c t i o n  on Brake Thermal E f f i c i e n c y  58  Figure  4.6  - T y p i c a l C y l i n d e r Pressure Trace Apparent Point  of I g n i t i o n S t a r t  and  Figure  4.7  - Apparent  Point  of  Ignition  Start  at V a r i o u s  Loads  60  s t a r t u n t i l 2 degrees a f t e r t o p dead c e n t r e . raised  As  the load  t o h a l f of f u l l l o a d , t h e i g n i t i o n p o i n t i s advanced by a  degree  probably  pressure  due t o t h e i n c r e a s e d end-gas t e m p e r a t u r e .  vs crank a n g l e t r a c e r e v e a l s the  pressure  of  about  50  kPa  increase  corresponding  in a direct (1980)  f o r t h e above l o a d i n c r e a s e .  r e s u l t obtained  in a  direct  to  suggest  a  significant effect  than  3  (1955)  by  Karim  ignition  l e v e l of t u r b u l e n c e  delay  prior to  i n prechamber engine does not  have  on i g n i t i o n d e l a y of the p i l o t d i e s e l .  the absence of a i r r e s t r i c t i o n , t h e p o i n t later  degrees.  and  t h e extended  that the higher  the i g n i t i o n of p i l o t d i e s e l  The  i n j e c t i o n engine about 1.5 degrees.  These agreements i n magnitude of seems  2  by Moore and M i t c h e l l  i n j e c t i o n engine was about 2 degrees  also  The  i n end-gas  a d d i t i o n of gas extends the i g n i t i o n d e l a y by 1 t o The  is  degrees  of  ignition  In  i s no  ATDC f o r a l l the l o a d s and p i l o t d i e s e l  flow r a t e s t e s t e d . To study injection  the e f f e c t  timing,  on  thermal  efficiency  of  varying  t h e t i m i n g was advanced by 5 and 10 degrees  f o r two l o a d s e t t i n g s ,  143 and 278 kPa i n brake  pressure.  r a t e of p i l o t d i e s e l was c o n t r o l l e d  The  about 20 p e r c e n t F i g . 4.8  flow  of t o t a l energy  input.  The  mean  lower  load  efficiency very  conditions.  The  f o r the corresponding  little,  as  of  improvement  graph  ignition  start  to  f o r both  i n brake  change i n i n j e c t i o n  shown by t h e upper graph.  the t i m i n g by 5 degrees r e s u l t s point  t o be of  shows t h a t advancing t h e i n j e c t i o n t i m i n g by 5 degrees  advances t h e p o i n t of i g n i t i o n t o t o p dead c e n t e r the  effective  thermal  timing  is  F u r t h e r advance of  i n advancement of 4 degrees  of  BTDC.  the The  apparent thermal  61  CN  C3  bmep 278 kPa  CD . CM  a  CM  OJ  ro  143 kPa  LO OJ ~~  ro  J- cr, ,  T  r  1—i—r  i  i  i  i  r  i—i—i—r  -1—1  V—I  1  •Is I  ro  CZl  c£ T 1  in. i  ~i 8.0  i 10.0  r~i—i—i—i—i—i—i—r 12.0  14.0  16.0  18.0  Injection Timing Figure  4.8  20.0  22.0  24.0  26.0  (deg BTDC)  - E f f e c t o f V a r y i n g I n j e c t i o n T i m i n g on Brake Thermal E f f i c i e n c y and Apparent P o n i t o f I g n i t i o n S t a r t  62  efficiency  o f t h e low l o a d o p e r a t i o n  effective  pressure  operation trend  in  pressure.  no  improvement,  in  while  brake  fear  of  The t e s t s f o r h i g h e r excessive  increase  exhibits a  load conditions in  mean  that of the  o f 278 kPa i n b r a k e mean e f f e c t i v e p r e s s u r e  to deteriorate.  avoided  shows  o f 143 kPa  maximum  were  cylinder  63  4.2 C y l i n d e r P r e s s u r e  4.2.1  C y l i n d e r pressure i n Unmodified For  each  randomly  selected  measured a t every crank a n g l e . angle  were  than  Engine  cycle  The  c y l i n d e r p r e s s u r e was  pressure  values  averaged over 30-50 c y c l e s .  at  The engine  and the i n j e c t i o n t i m i n g were f i x e d a t 1600 rpm and 12.3 BTDC r e s p e c t i v e l y .  F i g . 4.9 shows t h e P-V diagrams  o p e r a t i o n w i t h v a r i o u s l o a d s e t t i n g s r a n g i n g from  to  load.  The low l o a d o p e r a t i o n s r e v e a l  speed degree  for straight  diesel full  each  idling  the delay  until  a f t e r t h e t o p dead c e n t r e of s i g n i f i c a n t r i s e i n p r e s s u r e due t o combustion.  The maximum c y l i n d e r p r e s s u r e reached a t f u l l  o p e r a t i o n i s about The expansion  load  7870 kPa (1140 p s i ) .  -cylinder  pressure  processes  and  volume  in internal  a p p r o x i m a t e l y r e l a t e d by f o l l o w i n g  of  compression  combustion  engines  and  can be  relationships:  n P V  =  const  or Ln(P) = n Ln(V) + c o n s t The exponent 'n' would be e x a c t l y t h e r a t i o of s p e c i f i c heats i f the working f l u i d was an i d e a l gas w i t h c o n s t a n t p r o p e r t i e s , and the  compression  frictionless.  or For a  expansion mixture  process  was  of  gases  real  adiabatic  and  at  combustion  p r e s s u r e s , the i d e a l gas i s a good a p p r o x i m a t i o n and  f o r small  65  frictional  effect,  small  heat  transfer  t o the w a l l s ,  slowly  changing p r o p e r t i e s the above r e l a t i o n s h i p i s v a l i d w i t h constant  value  of  'n'.  nearly  The l n ( P ) - l n ( V ) p l o t t h u s p r o v i d e s an  approximate but c o n v e n i e n t means t o i d e n t i f y the p o i n t s beginning  and  the  end of the combustion.  F i g . 4.10  l n ( P ) - l n ( V ) p l o t of the s t r a i g h t d i e s e l o p e r a t i o n . indicates  the  separate  prechamber  full  centre. short  load,  the  initial  subsequent  line  near  combustion  the  distinctive  starts  line.  at lower l o a d s .  combustion  This  in  •expansion  the  first  process  The  development. near t o p dead  recognized  by  a The  burned  escape diesel-air  rate  of  The  first the  The  then t a k e s p l a c e i n the main chamber. flow  little  seems to short  stage  that  the  the  initial  period  is  prechamber  diesel  second  no  of  of  doubt  the  hot  further  stage  combustion  As the l o a d i s reduced t o f u e l i s reduced t o a s m a l l  amount and the combustion i n the prechamber requiring  less  m i x t u r e and m i x i n g w i t h a i r which  has r e s i d e d i n the main chamber.  the  It  corresponds  the  from  is  i d l i n g o p e r a t i o n shows no s i g n  stage  following  a s s o c i a t e d w i t h the  complete,  figure  characteristic  incomplete combustion i n the prechamber.  idling,  The  l n ( v o l u m e r a t i o ) of 0.65.  the 2-stage combustion c h a r a c t e r i s t i c .  partially  shows the  stage of combustion i s i d e n t i f i e d by the d e v i a t i o n of  p r e s s u r e from a s t r a i g h t  of  pressure  A s h o r t p e r i o d of e x p a n s i o n which i s straight  the  and main-chamber s t a g e s of  combustion through t h e i r e f f e c t s on the At  of  is  probably  combustion  in  the  nearly main  chamber. Fig. and  4.11  straight  compares t y p i c a l i n d i c a t o r diagrams of diesel  operations.  The  dual-fuel  dual-fuel operation  Log C y L Volume R a t i o Figure  4.10  Ln  P-V  Diagram  of  Straight  (V/VbdcJ Diesel  Operation  68  e x h i b i t s a much slimmer P-V diagram, w i t h much of t h e combustion t a k i n g p l a c e w i t h i n , a narrow ln(P)-ln(V)  diagrams  range  of  i n Fig.' 4.12  cylinder  shows  combustion c h a r a c t e r i s t i c s of  dual-fuel  operations.  diagram  The  ln(P)-ln(V)  effect  recognized  and of  in straight  i s particularly  combustion  noticeable  straight  with in  rapid  propagation  contrast  to  which  This  i s quite  operation.  high  d u r a t i o n of d u a l - f u e l o p e r a t i o n  t h a t of s t r a i g h t d i e s e l o p e r a t i o n .  load  combustion  The  where the  i s much s h o r t e r than would  be  consistent  of flame f r o n t s i n the g a s - a i r  t h e slower  diesel  dual-fuel operation  diesel  at  The  t h e very d i f f e r e n t  shows no o b v i o u s i n t e r m e d i a t e e x p a n s i o n p e r i o d distinctively  volume.  mixture,  in straight  diesel  i n maximum c y l i n d e r  pressure  operat i o n . F i g . 4.13  shows  t h e change  w i t h l o a d v a r i a t i o n f o r s t r a i g h t d i e s e l and d u a l - f u e l with At  p i l o t d i e s e l c o n s i s t i n g 20 percent high  load  operation  the maximum  i s very  operation.  much  cylinder  higher  than  of t o t a l energy i n p u t . pressure  t o 84 p e r c e n t  dual-fuel operation  of  dual-fuel  t h a t of s t r a i g h t d i e s e l  At brake mean e f f e c t i v e p r e s s u r e  corresponds  operation  of 714  kPa, which  of f u l l l o a d , the maximum p r e s s u r e of  i s about 35 p e r c e n t  higher  than t h a t of t h e  straight d i e s e l operation. The  maximum  cylinder  pressures  of d u a l - f u e l o p e r a t i o n a t  v a r i o u s l o a d s and p i l o t d i e s e l r a t e s a r e shown i n F i g . 4.14. F i g 4.15 shows t h e comparison of maximum r a t e pressure  rise  at  various  maximum r a t e of p r e s s u r e  load s e t t i n g s .  of  cylinder  F i g . 4.16 shows t h e  r i s e at various p i l o t d i e s e l rates.  30  Figure  4.12  1  1  3  1—I—I 5  I III  1  lO"  1 1  L o g C y l . Volume R a t i o  - C o m p a r i s o n o f L n P-V  Diagrams, f o r D u a l - F u e l  1  3  1—I—I  (V/VbdcJ  5  and S t r a i g h t  1  I II 1  Diesel  )Q  4  Operation  o  Comparison of Maximum C y l i n d e r P r e s s u r e s D u a l - F u e l and S t r a i g h t D i e s e l O p e r a t i o n  for  Figure  4.14 - Maximum C y l i n d e r P r e s s u r e at V a r i o u s Loads  <  o  co _  10  CL O  o  injection timing 12.3 d e g . btdc  X  o o 100  200  ~r  400  300  T  500  Brake Mean Effective  T  600  800  700  Pressure  (kPa)  F i g u r e 4.15 - Comparison of Maximum Rate of C y l i n d e r P r e s s u r e R i s e for  D u a l - F u e l and S t r a i g h t D i e s e l  Operation  900  ez  74  One of t h e most s e r i o u s w i t h n a t u r a l i s t h e very the  engine,  features  of  large increase  dual-fuel  i n m e c h a n i c a l l o a d i n g of  unless the p i l o t d i e s e l i n j e c t i o n i s retarded.  s e c t i o n 4.2.3, i t w i l l be shown how peak p r e s s u r e s rates  of  injection  operation  pressure  and  In  maximum  r i s e can be g r e a t l y reduced by r e t a r d i n g t h e  timing.  4.2.2 E f f e c t of R e s t r i c t i n g I n t a k e A i r The e f f e c t on intake  a i r was  maximum  cylinder  considered  (50 p e r c e n t of f u l l  f o r two  15 p e r c e n t  As  of  total  mentioned  restriction  was  characteristics. pressure  was  restricting  l o a d c o n d i t i o n s , 428 kPa  energy  before  input.  F i g . 4.17 shows the  with r e s t r i c t i o n  of  intake  t h e maximum amount of a l l o w a b l e a i r  limited  by  Substantial  achieved  load)  The flow r a t e of p i l o t d i e s e l  change i n maximum c y l i n d e r p r e s s u r e air.  of  l o a d ) and 571 kPa (67 p e r c e n t of f u l l  i n brake mean e f f e c t i v e p r e s s u r e . was  pressure  the  turbocharger  reduction  without  surging  i n maximum  exceeding  the  cylinder throttling  limitation.  W i t h maximum a i r r e s t r i c t i o n when t h e l o a d i s below  67  of f u l l  percent  l o a d t h e maximum c y l i n d e r p r e s s u r e  exceed t h a t of s t r a i g h t d i e s e l o p e r a t i o n  at f u l l  does not  l o a d , which  is  about 8000 kPa. Fig.  4.18  combustion throttling.  shows  with  t h e change  reduction  The p r e s s u r e  of  i n pressure  manifold  just  pressure  before due  to  j u s t p r i o r t o combustion was o b t a i n e d  Figure  4.17  - Effect  of  Intake  Air Restriction  on  Maximum  Cylinder  Pressure  9Z  77  from t h e c y l i n d e r p r e s s u r e vs crank angle just  trace  as  the point  p r i o r t o t h e s i g n i f i c a n t p r e s s u r e r i s e due t o combustion.  For both of the l o a d c o n d i t i o n s the change i n maximum pressure  i s of  t h e same  p r i o r t o combustion. 428 kPa  o r d e r of t h e change i n the p r e s s u r e  At t h e brake mean  the r e d u c t i o n  and  brake mean  prior  t o combustion  cylinder  of  pressure  pressure  4.38 from 5.01 m /min. 3  of  c y l i n d e r p r e s s u r e of 500 kPa. At the of  571 kPa  450 kPa f o r t h e p r e s s u r e p r i o r t o combustion maximum  pressure 3  i n maximum  effective  effective  of a i r f l o w r a t e from 4.9 t o 4.3 m /min  r e s u l t e d i n the drop i n the p r e s s u r e 400 kPa  cylinder  when  the r e d u c t i o n i s and 500 kPa f o r the  the a i r flow i s r e s t r i c t e d t o  T h i s seems t o suggest  t h a t the r e d u c t i o n  of maximum c y l i n d e r p r e s s u r e when t h e i n t a k e a i r  is  restricted  i s due m a i n l y t o the decreased p r e s s u r e p r i o r t o combustion (due to r e d u c t i o n i n m a n i f o l d p r e s s u r e ) . The e f f e c t on t h e maximum r a t e of c y l i n d e r p r e s s u r e r i s e of intake  a i r r e s t r i c t i o n i s shown i n F i g . 4.19.  The r e s t r i c t i o n  of i n t a k e a i r seems t o r e s u l t i n h i g h e r maximum r a t e of c y l i n d e r pressure r i s e .  T h i s t r e n d i s b e l i e v e d t o be t h e consequence  the  gas-air  increased  propagation.  mixture  strength  which  favours  of  flame  Figure  4.19  -  Effect  of  Intake  Air  Restriction  on  Maximum  Rate  of  Cylinder Pressure  Rise  79  4.2.3 E f f e c t o f V a r y i n g I n j e c t i o n The  effect  injection  on  timing  was  p r e s s u r e o f 571 k P a . 10 p e r c e n t  maximum  of t o t a l  Timing  cylinder  considered The f l o w  pressure  for a  rate of  energy i n p u t .  are  shown  in  diesel  the  pressure  retardation Fig.  to  retardation  F i g . 4.20.  As  significant  combustion  cylinder  by  Retardation  was  2  and  of merely The  change  f o r the corresponding  was 460 kPa a s shown i n F i g . 4.21.  4.22 shows t h e P-V  timings.  centre  prior  used  The r e d u c e d maximum  4 d e g r e e s r e d u c e d t h e maximum p r e s s u r e by 1850 k P a . in  retarding  b r a k e mean e f f e c t i v e  pilot  p r e s s u r e a s a r e s u l t of i n j e c t i o n t i m i n g 4 d e g r e e s CA  of  diagram  the i n j e c t i o n timing  pressure rise  i s retarded  for different  i s retarded  the point  further  from t h e t o p  dead  The maximum  rate  F i g . 4.20.  The  e x h i b i t i n g l e s s s t e e p and w i d e r t r a c e .  of p r e s s u r e r i s e was a l s o  injection  r e d u c e d a s shown  in  c h a n g e i n t h e r m a l e f f i c i e n c y due t o i n j e c t i o n t i m i n g  of the  retardation  was l e s s t h a n 0.5 p e r c e n t . Test  at higher load,  714 kPa ( 8 3 % o f f u l l energy  input  a t a b r a k e mean e f f e c t i v e p r e s s u r e o f  load), with  10 p e r c e n t  and 4 degrees r e t a r d a t i o n  fractional  showed r e d u c t i o n  p r e s s u r e f r o m 10.2 t o 7.7 MPa a n d maximum r a t e from due  2.1  t o 1.4 MPa/deg.  t o the i n j e c t i o n retardation It  i s estimated that  would r e q u i r e this  The l o s s  would  in  loss  1 percent.  full-load  dual-fuel  of  rise  i n brake thermal e f f i c i e n c y  4 t o 6 degrees of i n j e c t i o n t i m i n g result  o f peak  of p r e s s u r e  was a b o u t  safe  diesel  thermal  operation  r e t a r d a t i o n and  efficiency  of  1 to  80  o l  on  0.0  i  i  0.04  i  i  0.08  Figure  i  i  0.12  4.22  i  -  i  0.16  i—i—i—i—i—i—i—i—|—i—|—i—|—|—|—i—|—|—i—|—,—r 0.2  Effect  0.24  0.28  0.32  0.36  C y l i n d e r Volume R a t i o  of  Varying  Injection  0.4  0.44  (V/Vbdc)  Timing  on  0.48  P-V  0.52  Diagram  0.56  0.6  83  2 percent.  At l o a d s beyond f u l l l o a d , s i n c e i t i s expected t h a t  the thermal  e f f i c i e n c y of d u a l - f u e l o p e r a t i o n w i t h o u t  injection  r e t a r d a t i o n would surpass  t h a t of s t r a i g h t d i e s e l o p e r a t i o n (see  section  dual-fuel  4.1.1),  the  i n j e c t i o n r e t a r d a t i o n t o assure would  still  result  in  be  a  safe  thermal  straight diesel operation.  level  efficiency  Retarding  p r a c t i c a l , and n e c e s s a r y  f u e l operation at high load.  operation  witn of  peak  close  sufficient pressure t o t h a t of  i n j e c t i o n t i m i n g seems  to  means of e n s u r i n g the s a f e d u a l -  CH.V  84  Analysis  of Apparent Energy R e l e a s e  5.1 G e n e r a l One  of  combustion estimation rate,  from  the  processes  the  effective in  the  measured  cylinder,  of  of  interpreting  the  engines  the  combustion energy  release,  the on  heat the  transfer piston  burning  combustion  gas  mixtures  through the c y l i n d e r head.  heat t r a n s f e r and thermodynamic  m i x t u r e s , the apparent energy r e l e a s e  is  or  p r e s s u r e d i s t r i b u t i o n . The  a f f e c t s the i n t e r n a l energy of the  w a l l s , and the work done estimation  means  internal  of the r a t e of c h e m i c a l  energy r e l e a s e d inside  most  due t o  By  appropriate  properties  combustion  of gas can  be  e s t i m a t e d from measured v a l u e s of c y l i n d e r p r e s s u r e and change i n c y l i n d e r volume. The a n a l y s i s p r o v i d e s a q u a l i t a t i v e the  combustion  operation.  processes  of  dual-fuel  and  picture  straight  of  diesel  85  5.2 Method of c a l c u l a t i o n  5.2.1 D e f i n i t i o n s , E q u a t i o n s , and Assumptions  When  both  the  intake  and  exhaust  v a l v e s a r e c l o s e d the  m i x t u r e s of a i r and burned and unburned f u e l s can as  a  system  undergoing  be  considered  a change of s t a t e , which i s bounded by  c y l i n d e r w a l l s and p i s t o n head (see F i g . 5.1). The f i r s t  law  of  thermodynamics then can be a p p l i e d t o the system f o r a s m a l l time change 6 t :  f i r s t law  6Q = dE + 5W where Q - heat t r a n s f e r t o the system E  energy of the system  W - work done by the system  S i n c e the o n l y s i g n i f i c a n t e n e r g i e s of the system are  the  internal  involved  here  and c h e m i c a l energy, the energy of the system  can be assumed t o c o n s i s t of the f o l l o w i n g :  E = U + CE where U - i n t e r n a l energy of the system CE - c h e m i c a l energy of the system  Figure  5.1  - Control  Volume  f o r Apparent  Energy  Release  Analysis  87  Then t h e c o r r e s p o n d i n g f i r s t law becomes:  6Q = dU +dCE + 6W  For  a  finite  change  change from s t a t e  /  of t i m e , A t , w i t h the system undergoing a to  state  the  first  law can be  integrated to y i e l d the f o l l o w i n g :  •Q.=  1^1+1  AU + ACE + 1.W.i+1. where AU = U  - U.  i + 1  ACE = CE.., " CE. 1+1 l I f P i s d e f i n e d t o be the average p r e s s u r e of t h e system : l i+1  i+1  I  then t h e work done on t h e system can be approximated a s :  i•Wi.+ 1 - i• iP • + 1, ,i +(V. 1 . - IV. ) where - c y l i n d e r volume a t i ^ s t a t e J  1  f c  The change i n c h e m i c a l energy of t h e system can be e s t i m a t e d a s :  ACE  jm  f j U c j  88  where m^j  - mass o f j i  f c  ^  of  Now  a finite  difference  f fj cj m  Evaluation  "  i +  chemical energy change  j  these  h  A  heat transfer  of  t  during  energy of combustion  fuel  "  U  internal energy change  terms  burned  gas)  form of t h e f i r s t  iQ l  -  U  fuel  for natural  - internal  c  n  (j=1 for diesel,  state,  j=2 u j  t  will  be  i  law may  P  i + 1  A  be w r i t t e n as:  (Eqn  V  5.1)  work  discussed  in  subsequent  sections.  Assumpt i o n s I n d e v e l o p i n g t h e method o f c o m p u t a t i o n s e v e r a l were made, 1.  The  assumptions  namely: constituents  ideal  gases  of  with  the mixture  i n t h e c y l i n d e r behave as  temperature-dependent  thermodynamic  properties. 2.  The  gaseous c o n s t i t u e n t s  of t h e m i x t u r e a r e c o n s i d e r e d  homogeneous and u n i f o r m i n non-uniformity ignored.  in  the  thermodynamic  rate  state  :  t o be spatial  of c h e m i c a l energy r e l e a s e  is  89 3.  The c o m p o s i t i o n of the combustion equilibrium  4.  The  variation  time can be a d e q u a t e l y a  corresponds  to  dissociation.  continuous  over  products  of thermodynamic p r o p e r t i e s w i t h  represented  by  stepwise  variation  s m a l l time i n t e r v a l c o r r e s p o n d i n g t o 1 degree  crank  angle. 5.  Presence of r e s i d u a l gas d u r i n g the i n t a k e i s n e g l e c t e d .  6.  O v e r l a p of i n t a k e and exhaust v a l v e i s i g n o r e d .  7.  At any g i v e n i n s t a n t the burned f r a c t i o n s of the n a t u r a l gas and d i e s e l f u e l s a r e the same.  Heat T r a n s f e r In  order  to  account f o r t h e heat t r a n s f e r between the gas  m i x t u r e and t h e c y l i n d e r w a l l s , modes  were  considered,  both  convective  and  f o l l o w i n g t h e procedure of  radiative  Annand(l963)  whose e q u a t i o n i s :  q/A  =  a(k/D)(R) (T - T b  w a l l  >  +  c(T« - T ^ ^ )  where q - heat t r a n s f e r  rate  A - s u r f a c e a r e a of c y l i n d e r  walls  k - t h e r m a l c o n d u c t i v i t y of t h e m i x t u r e D - bore R - Reynolds number d e f i n e d as pVD//x where p - d e n s i t y of t h e m i x t u r e  -  90  "V - mean p i s t o n  velocity  n - v i s c o s i t y of the m i x t u r e T - m i x t u r e temperature T  wall ~ y^^ ^ c  n c  e r  wall  temperature  a ,b,c - c o n s t a n t s  The the  first  c o n v e c t i v e heat t r a n s f e r and t h e second term w i t h t h e  order for  term w i t h the f i r s t o r d e r of temperature a c c o u n t s f o r  temperature  f o r t h e r a d i a t i v e . The c o n s t a n t s 'a' and 'b'  the convective  term  least-square-errors  to  were  selected  t h e apparent  to y i e l d heat  i n optimizing  apparent heat t r a n s f e r measured the  pressures  t h e two data  constants  obtained  a  f i t with  t r a n s f e r d u r i n g the  compression s t r o k e . A n o n l i n e a r l e a s t - s q u a r e s - f i t adopted  technique  of  loads.  was  f o r a l a r g e s e t of  (from  equation  5.1  and  w i t h no combustion and known c o n s t i t u e n t s of  m i x t u r e ) f o r d u a l - f u e l and s t r a i g h t d i e s e l o p e r a t i o n  range  fourth  F i g . 5.2  over  a  shows t h e f i t t e d c u r v e and data f o r  s t r a i g h t d i e s e l o p e r a t i o n a t brake  mean  effective  pressure  of  571 kPa. The o p t i m i z e d v a l u e s f o r t h e d i m e n s i o n l e s s c o n s t a n t s 'a' and 'b' were 0.47 and 0.7 r e s p e c t i v e l y . The v a l u e s  suggested  by  Annand(l963) f o r 'a' was 0.35-0.8 and f o r 'b' was 0.7. The c o n s t a n t 'c' f o r t h e r a d i a t i o n 3.3 x 1 0 "  1 1  radiation.  a  was  taken  t o be  kJ/K* as suggested by Annand f o r d i e s e l e n g i n e s . T h i s  v a l u e would c o r r e s p o n d t o t h e p r o d u c t constant  term  and  of  the  Stefan-Boltzmann  an e m i s s i v i t y of 0.58, a p p r o p r i a t e t o grey body  50 0 CO CD  I — I' CD  1  -30 0 I  Heat -10.0  I  10.0  I  I  X  X  * I x I  x  i  I  x  #  5 0 . 0  I  I  I  7 0 . 0  I  I  . 9 0 . 0  !  110.0  I  I  I  130.0  1  3  X IX  X  X  cn  3 0 . 0  I  (kJ/sec)  I  *l  cn  Transfer  .  X  X  X  ^  1  l  x  X  I  i  *  i  X  v.  a' ~t  o  ~I QJ  CJ  CD  o  X  , X X  te CL  —  <  ^ \ V  \  CO X ) CD m im ro  cn  3  3  CD ro  IJ Q  01  Q  operation  55  10  "CJ i cn cn ~o o o 5T  Q.  ro  a  cr  ght CMc  CL  in •o  CD  10  <—r  o CL  3  o CL  a TJ T3  a  TJ 3  o  a  Q cn  -to. CD  16  I—  92 It  was assumed t h a t the temperature of t h e w a l l , a t a g i v e n  l o a d , s t a y s c o n s t a n t throughout t h e c y c l e , with  the a p p l i e d  and  varies  linearly  l o a d . The measurements of w a l l temperature made  by Kamel and Watson(l979) on an i n d i r e c t - i n j e c t i o n R i c a r d o engine  showed t h a t t h e change i n w a l l temperature throughout the  cycle at  full  temperature.  load Their  was  less  than  10  percent  load.  calculated  In  the present  work  temperature  linearly  with  t h e w a l l temperature was  w a l l " 0.071(bmep) + 540 bmep i n kPa T  ,, i n K wall  The numbers o b t a i n e d from t h i s f o r m u l a f o r T percent  engine  the mean  from  T  10  of  data a l s o suggested t h a t t h e w a l l  of both prechamber and main chamber v a r i e d n e a r l y applied  swirl  of  those  measured  ^  are well  within  by Kamel and Watson a t the same  speed.  F i g . 5.3 shows a t y p i c a l c a l c u l a t i o n of t h e apparent r a t e of energy r e l e a s e  w i t h and w i t h o u t t h e adopted heat t r a n s f e r  model;  the computation procedure i s p r e s e n t e d l a t e r .  Dissociation In  computing  the constituents  of t h e combustion p r o d u c t s  e q u i l i b r i u m d i s s o c i a t i o n was assumed. The d i s s o c i a t i o n c o n s i d e r e d a r e as f o l l o w s :  reactions  with heat transfer  model  without heat transfer model straight diesel operation  OJ  TJ,  bmep - 571 kPa speed - 1600 rpm  QJ  in ro  UJ cn QJ o '  £"\ QJ^"  •f-» ro  CH cn  o  v. V ,  -la.o  tdc  I0.O  1 Crank  Figure  5.3  - Effect  1—  30. D Angle  o f Heat T r a n s f e r  T  50.0 (deg  flTDC)  Model on A p p a r e n t  v.  7D:0  Rate o f Energy  Release  94 a. C 0  <  2  > CO + 1/2 0  b. H 0 <  > 1/2 H  c. H 0 <  > H  2  2  d. 1/2 N  It  may  be  noted  calculations, and  that  + OH  + 1/2 0  2  + 1/2 0  2  2  <  2  2  2  > NO  i n h i s engine  mixture  Campbell(1977) c o n s i d e r e d the above d i s s o c i a t i o n s ,  i n a d d i t i o n t h e d i s s o c i a t i o n of 0 , H , and OH. 2  shown  t h e degree of d i s s o c i a t i o n  p r e s s u r e s and low temperatures Hence  dissociation  only  4  dissociation  2  As  will  i s small at the r e l a t i v e l y  of compression processes  ignition  were  be high  engines.  considered  i n the  equilibrium calculation. For  each s t e p of i n c r e m e n t a l time At and g i v e n p r e s s u r e and  temperature  of  equations  the m i x t u r e ,  were  solved  the following  f o r the number  s e t of  of moles of combustion  products: Y  CO 0,  = K.(P'/P)  v co  or  Y  2  (N +A)[N c o  +1/2(A+C-D)]  Q  2  (\ y  2  "  H  ot  < co N  YX ' 2  H  Y ?  "  2  A  VPVP)^  )  OH  i  =  K (P°/P)'  2  R  Y Y  H 0 2  or (N  u  +1/2B+C) ( N + B ) 2  H  QH  ( tot)"" N  ( H 0- - ^ N  B  2  C  2  - K (P°/P) B  nonlinear  :  95 Y H  2  Y  Y  °2  K (P7P) C  1  H 0 2  o r  (N  +l/2B+C)[(N  H  1  +l/2(A+C-D) ] "  Q  2  "  :  ^ t o t  ( H 0" " N  B  y  k  K [P°/P)  =  :  C  C )  2  Y  D _  NO  N  2  °2  V  or < NO+ ) N  D  (NXI - l / 2 D ) [ N  + l/2(A+C-D)]  4  N  tot  =  I  N  i  +  N  1/2(A  where  J 5  + B + C)  K^,Kg,K^,K^ for  are  reactions  ^CO'^NO' compositions. Nfjo'^NO' of  E  T  C  a  r  e  e  t  C  a  r  e  step  A,B,C,%Dare H 0,H 0,K' 2  2  reactions  P  is is  2  e  t  c  ^  u  i e  n  u  numbers 0  2  ^  i-  r  e  r  u  m  °^  m  0  prior  of  ^  e  to  s  the  of CO,, in  respectively. pressure,  mixture  «. i s t h e t o t a l tot the m i x t u r e .  moles  dissociated  a,b,c,d,  gas  m  D  combustion.  atmospheric the  l i l i  present  of  or  constants  a,b,c,d.  constituents  current  P°  equilibrium  101.3  kPa.  pressure.  number  of  moles  of  96 Given  the  pressure  equations  were  using  modified  a  constants, from  Fig. energy  5.4  Newton's  are  curves  Thermodynamics  temperature  simultaneously  which  fitted  and  solved  method.  f u n c t i o n s of  based  on  of f o r A,  The  the  mixture,  B,  C,  values  of  temperature,  thermodynamic  data  D,  the and  five N t  o  t  the  equilibrium  were  calculated  given  i n the  JANAF  Tables.  shows  a  typical  r e l e a s e computed  with  calculation and  without  of  the  apparent  dissociation.  rate  of  Figure  5.4  - Effect  of Equilibrium  Dissociation  Calculation  on  Apparent  Rate o f Energy  Release  98  5,2.2  Computation The apparent  equations  of  temperature piston  Procedure energy  mass  release  and  is  energy  obtained  by  conservation  solving  for  the  the  mixture  and the f r a c t i o n of f u e l burned. The work done on  the  i s computed from the smoothed p r e s s u r e d a t a and change i n  c y l i n d e r volume. The described  in  rate  section  of  heat  5.2.1.  transfer  is  estimated  as  The c o m p o s i t i o n of the m i x t u r e i s  computed w i t h the e q u i l i b r i u m d i s s o c i a t i o n assumption,  and  with  the e q u a t i o n s p r o v i d e d i n the p r e v i o u s s e c t i o n . C o n s i d e r a s m a l l s t e p i n the c a l c u l a t i o n state  of  the  mixture  start  s t a t e /; the f o l l o w i n g c o n d i t i o n s  i '  P  i ' CH. i' where the ( n  )  C, H , N , 2  2 6  2  The c a l c u l a t i o n procedure 1.  Assume  T..  1f  C n^'s  (  the  0 ,  I  with  {  2  2  i s as  knowledge  H > i j h a r e the numbers of moles of  1  H 0,  2  complete  The of  are g i v e n :  n  (fr).  1+1  which  changes from s t a t e / t o s t a t e  c a l c u l a t i o n s f o r s t a t e (i+1)  T  during  2  n  6  C0 , 2  CO,  H, 2  OH,  CH , 4  NO.  follows:  . ( f r a c t i o n of f u e l burned i n one to  1+1  step). 2.  O b t a i n the c o m p o s i t i o n molar f r a c t i o n s ( j ) ^ n  e x i s t i n s t a t e (i+1)  + 1  were t h e r e no d i s s o c i a t i o n .  which  would  99 With the assumed T^  and the measured p r e s s u r e P ^  + 1  equilibrium of  dissociation calculations  ^ j^i+i  to obtain  +1  the  perform values  which s a t i s f y the d i s s o c i a t i o n r e l a t i o n s h i p s i n  n  s e c t ion 5.2.1. For each s p e c i e s c a l c u l a t e the change i n the number of moles An.=  (n.).., 3 1+1  3  Compute  the  changes  -(n.). j i n chemical 1  energy ACE and i n t e r n a l  energy AU as ACE = ?An . ( u . • + Au .) j 3 3 3 where 0  l  u°£j = i n t e r n a l energy  of f o r m a t i o n  at 298 K AUj  =  U j ( T  i  +  )  1  -  Uj(298K)  AU = ? ( n . ) . ( u . ( T . , . ) - u.(T.)) j 3 3 > 3 1+  1  1  where U j - i n t e r n a l energy  of j * " * c o n s t i t u e n t 1  of gas m i x t u r e 6.  Compute ^Q^  and i j  7.  Check the f o l l o w i n g  w  +1  two c o n s e r v a t i o n e q u a t i o n s :  ACE = .Q. P  8.  i  1 i V  +  +  1  + 1  =  +1  +  AU  +  ^ ^ j ^ - H I  .W.  +1  >  R  T  i  +  1  I f the above two e q u a t i o n s a r e s a t i s f i e d then computation i s completed.  I f n o t , repeat from 1.  100  C y l i n d e r P r e s s u r e Data The  c y l i n d e r p r e s s u r e was  r e c o r d e d at every degree of crank  a n g l e . The measured v a l u e s were then averaged selected  c y c l e s . I t r e q u i r e d 20-30 minutes t o o b t a i n an  p r e s s u r e t r a c e of 30 c y c l e s w i t h the NEFF and  over 30-50 randomly  the  PDP/11  computer.  Because  data  of  aquisition  large  v a r i a t i o n s , the r e s u l t i n g p r e s s u r e - c r a n k angle smooth energy  enough  to  provide  averaged unit  cycle-to-cycle  curves  were  not  a smooth c a l c u l a t e d c u r v e of r a t e of  r e l e a s e . The p r e s s u r e - c r a n k a n g l e c u r v e s were smoothed  f i t t i n g a c u r v e between the o b t a i n e d d a t a . The  technique involved  f i t t i n g a piece-wise cubic polynomial (continuous to derivative)  inverse  the  second  between the p r e s s u r e measurements over a crank  range of 180 degrees w i t h of  minimization  in  by  square  angle  errors.  The  the v a r i a t i o n i n the s l o p e of the p r e s s u r e t r a c e f o r  f o u r n e i g h b o u r i n g p o i n t s were used i n p r o v i d i n g  the  weight  for  the l e a s t - s q u a r e s f i t . Fig.  5.5  shows the r a t e of energy  release  calculated  unsmoothed and smoothed p r e s s u r e - c r a n k angle c u r v e s . The p r e s s u r e c u r v e showed except  very  small  visually  detectable  i n the r e g i o n near the peak of the combustion  Computer Program f o r Apparent Energy  program  read  in  change,  pressure.  t o execute  the  section.  The  the c y l i n d e r p r e s s u r e d a t a and  flow  procedure d e s c r i b e d  initially  smoothed  Release  The main f u n c t i o n of the computer program was computation  from  in  the  previous  smoothed not  smoothed  cn  _ cd" CD OJ  -o  straight diesel operation  CD  OJ cn ro OJ  bmep -  571 kPa  speed -  1600 r p m  "  —H (O  QJ o ' "1_  UJ 0 J  ro CC  d  C3 "  CD"  -1D.0  tdc  1 30.0  10.0  Crank Figure  5.5 - E f f e c t  o f Smoothing  Angle  Pressure  50.0  70.0  (deg.RTDC) Data on A p p a r e n t  Rate o f Energy  Release  102  r a t e s of a i r and f u e l s a l o n g w i t h d a t a f o r o p e r a t i n g The  conditions.  p r e s s u r e data were then smoothed-and volumes of the c y l i n d e r  f o r a l l crank a n g l e s were computed. S u b s e q u e n t l y , f o r each degree of  crank  a n g l e , e q u a t i o n s f o r energy and mass c o n s e r v a t i o n were  s i m u l t a n e o u s l y and i t e r a t i v e l y s o l v e d f o r the temperature and the fraction  of  f u e l burned. A m o d i f i e d Newton's method was used i n  s o l v i n g the system of n o n l i n e a r e q u a t i o n s . that  combustion may  The  program  assumed  take p l a c e at anytime a f t e r the i n j e c t i o n of  d i e s e l f u e l . B e f o r e the d i e s e l i n j e c t i o n p o i n t , the program an  alternate  route  took  and merely computed the m i x t u r e temperature  d i r e c t l y from i d e a l gas law. F i g . 5.6 shows the f l o w c h a r t of procedures computer  adopted  program  in  the  computer  program. A l i s t i n g of the  i s p r o v i d e d i n Appendix  t y p i c a l output of the  the  E.  Fig.  5.7  shows  a  program.  Check of Computation In  order  to  c o n f i r m q u a n t i t a t i v e l y the c o r r e c t n e s s of the  method used, the computed amount  of  averaged  output was compared w i t h a c t u a l  amount of chemical  c y c l e from the computer fuel  energy  input.  consumed  Because  the  fuel  energy  computed  rate  per  of  energy r e l e a s e i s e s s e n t i a l l y z e r o except f o r the crank  a n g l e i n t e r v a l of -10 t o +90 degrees a f t e r top  dead  center,  it  was n e c e s s a r y t o i n t e g r a t e the energy r e l e a s e o n l y i n t h i s range. Table 5.1  shows the r a t i o s of the computed t o a c t u a l  energy  consumed f o r v a r i o u s o p e r a t i o n s . From a l l the r a t i o s shown i n the t a b l e , i t i s seen t h a t the agreements  between  the  computed  and  103  read i n flow r a t e of d i e s e l , gas, a i r P ( 0 ) , C.A. a t i g n i t i o n , injection read i n of d i e s e l , products  properties combustion  gas, a i r ,  comp u t e V(0) smooth repeat  t o 9JJ  f o r 0 = -89  number  compute T from i d e a l gas  P(O)  update of moles of  reactants  amount  set energy r e l e a s e  compute stoichiometric products  = 0  for  Figure  T  1  5.6 - F l o w c h a r t o f Computer Release  account dissociation  are mass and energy conserved?  yes  Energy  combustion  compute heat transfer  print P, T, h e a t transfer, energy release  0  burnt,  law  compute heat transfer  set = 0 +  guess of f u e l  Program f o r Apparent  Analysis  104  Figure  5.7-  Typical Energy  Output Release  of  Computer  Analysis  Program  for  Apparent  LOAD (kPa)  MODE OF OPERATION  FRACTIONAL D I E S E L ENERGY INPUT (%)  ACTUAL ENERGY CONSUMED (kJ)  COMPUTED ENERGY CONSUMED (kJ)  RATIO OF COMPUTED TO A C T U A L ENERGY CONSUMED  -  0.79  0.83  1.06  s t raigh t diesel  -  1 . 74  1.67  0.96  571  s traight diesel  -  3 .05  2.84  0.93  713  s traight diesel  -  3 . 75  3.48  0.93  856  s traight diesel  -  4 . 58  4.26  0.93  571  dual-fuel  20 . 9  3.17  3.01  0.95  571  dual-fuel  10 . 2  3.14  2 .95  0.94  0  s traight diesel  279  Table  5.1 -  Comparison  of A c t u a l  and Computed  Fuel  Energy  Consumed  106  actual  energy  consumed  a r e q u i t e good. The s m a l l disagreements  are p r o b a b l y due t o the v a r i a t i o n i n inadequacy  of  heat  transfer  assumptions made d u r i n g the should  be  noted  that  the  heating  values  model, unburned  course  of  method  amount of unburned  of  fuels,  f u e l , and v a r i o u s development.  It  gas e s c a p i n g the  c y l i n d e r was not s u b t r a c t e d from the a c t u a l amount of f u e l energy input.  107  5.3  Analysis  5.3.1  O p e r a t i o n s w i t h U n m o d i f i e d Engine The c a l c u l a t e d r a t e of energy r e l e a s e f o r  operation  with  i n F i g . 5.8. declines  l o a d s r a n g i n g from i d l i n g t o f u l l  At i d l i n g near  the  top  dead  the  model  seems  to  the  curve  T h i s may  transfer  underestimate  diesel  l o a d i s shown  center  t o n e g a t i v e v a l u e s p r i o r t o the peak.  r e s u l t of the inadequacy of the heat loads  straight  be the  model.  the  At  rate  low  of  heat  t r a n s f e r , r e s u l t i n g i n n e g a t i v e v a l u e s f o r the apparent r a t e energy the  release.  The roughness of the c u r v e s d u r i n g and  of  towards  end of combustion i s due t o roughness i n the p r e s s u r e d a t a .  The roughness c o u l d have been reduced by f u r t h e r  smoothing  the  pressure data. At  full  load(bmep  =  856 kPa) the r a t e of energy  r e v e a l s two s t a g e s of c o m b u s t i o n .  The f i r s t s t a g e  lasts  12  to  the  second stage combustion becomes l e s s d i s t i n c t i v e .  that and  14 degrees a f t e r t o p dead c e n t r e .  second  calculated  to  cumulative  s u p p o r t s t h i s view. centre,  combustion  which  is  Near  release  the  cumulative  main in  cumulative  It  seems  prechamber  chamber. F i g . 5.9  after  the  The further  top  dead  p o i n t s e p a r a t i n g the two energy  release  o t h e r than i d l e i s n e a r l y the same at about  i s about 30% of the t o t a l load.  the  13 degree C.A.  approximately  s t a g e s of combustion, the loads  energy  in  until  As the l o a d d e c r e a s e s  the f i r s t peak c o r r e s p o n d s t o combustion i n the the  release  energy  The v o l u m e t r i c r a t i o of prechamber  for  1.3 k J .  release  at  the This full  t o the t o t a l volume at  Figure  5.8  Rate o f  Energy  Release  of  Straight  Diesel  Operstion  at  Various  Loads  Figure  5.9  Cumulative  Energy  Release  of Straight  Diesel  Operation  at Various  Loads  110  the  t o p dead  centre  i s about 25 p e r c e n t .  s u g g e s t s t h a t t h e combustion i n s t r a i g h t prechamber  engine  consists  of  two  stages-prechamber and main chamber. t h e time  period  diesel  distinct  From  that  place  increases with the increase i n load.  very  The maximum r a t e  input.  straight  diesel  F i g . 5.10  operation  of  in  increases nearly l i n e a r l y with a i r •*  F i g . 5.11 shows t h e r a t e of energy r e l e a s e i n which  pilot  diesel  fuel  20 p e r c e n t of t h e t o t a l energy i n p u t , and in diesel  injection  timing.  with  dual-fuel  accounts when  f o r about  no  change  release.  has  The most noteworthy  f e a t u r e i s t h e n e a r l y t w o f o l d i n c r e a s e i n t h e maximum  rate  of  I t i s observed from the f i g u r e t h a t t h e change  i n combustion d u r a t i o n w i t h v a r y i n g when  shows  t h e combustion  fuel ratio.  energy  of  on a i r - f u e l r a t i o of the maximum r a t e of energy  I t i s seen t h a t t h e r a p i d i t y  made  be  At v e r y low l o a d s the r a t e of energy r e l e a s e  release.  been  i t can  r a p i d l y a l t h o u g h t h e maximum r a t e of energy r e l e a s e  dependence  operation  subsequent  l o a d and i n c r e a s e s as t h e  i s l i m i t e d by t h e t o t a l d i e s e l energy the  and  of  d u r i n g which the combustion t a k e s  energy r e l e a s e i s t h e s m a l l e s t a t f u l l  rises  operation  F i g . 5.9  seen  load i s decreased.  Thus the a n a l y s i s  load  i s relatively  compared t o t h a t of s t r a i g h t d i e s e l o p e r a t i o n .  small  The shapes  of t h e r a t e of energy r e l e a s e c u r v e s e x h i b i t v e r y l i t t l e of t h e two-staged  combustion  characteristic  straight d i e s e l operation. energy  release  i s observed  in  The r a p i d i t y of r i s e of t h e r a t e  of  increases with the increase i n load.  shows t h e maximum r a t e of energy gas-air  mixture  which  strength.  release The  plotted  F i g . 5.12  against  figure •indicates  the  strong  Ill  n - mn  1  1  tdc  10.0  1  5.11  1  30.0  Crank Figure  1  - Rate o f Energy  Release  Rngle o f Dual-Fuel  1  1  50.0  r~  70.0  (derj PTDC1 Operation  at Various  Loads  ^  O  r  _  g  Figure  5.12  - Effect in  gas-air  stoichiometric  of Gas-Air  Dual-Fuel  actual  Mixture  mass  gas-air  ratio mass  ratio  S t r e n g t h o n Maximum  Rate o f Energy  Release  Operation i  114  dependence of t h e r a p i d i t y of combustion on t h e g a s - a i r strength.  The c u m u l a t i v e energy r e l e a s e of d u a l - f u e l  mixture operation  c o r r e s p o n d i n g t o t h e c u r v e s i n F i g . 5.11 i s shown i n F i g . 5.13. F i g . 5.14 and F i g . 5.15 compare s t r a i g h t d i e s e l fuel  operation  at  85  and  33  percent  of• f u l l  F i g . 5.14 i t i s seen t h a t f o r h i g h l o a d o p e r a t i o n d u r a t i o n of t h e d u a l - f u e l o p e r a t i o n  r e l e a s e i s about 3.7 times h i g h e r . shape  of  operations  of  energy  The remarkable d i f f e r e n c e i n  of  combustion  are  different.  Evidently  d i e s e l spray which p e n e t r a t e s  combustion  p r o p a g a t i n g as a t u r b u l e n t flame through of  the f u e l  does  i g n i t e d by t h e  t h e main chamber as a hot  mixture adjacent t o evaporating  most  the  i s m a i n l y c a r r i e d out by flame  In s t r a i g h t d i e s e l o p e r a t i o n ,  Since  t h e combustion  rate  p r o p a g a t i o n through' the premixed g a s - a i r m i x t u r e ,  fuel-air  From  t h e r a t e of energy r e l e a s e f o r t h e two modes of  combustion i n d u a l - f u e l o p e r a t i o n  jet.  load.  s u p p o r t s the view mentioned i n s e c t i o n 4.2.1 t h a t t h e  mechanisms  burning  dual-  i s much s h o r t e r than t h a t of  the s t r a i g h t d i e s e l o p e r a t i o n , and the maximum  the  and  occurs  i n the  f u e l drops r a t h e r than the e n t i r e  mixture.  not r e q u i r e e v a p o r a t i o n  i n the  former case i t i s r e a s o n a b l e t h a t t h i s mode of combustion  should  be f a s t e r . F i g . 5.16 shows the r a t e of energy r e l e a s e f o r a operation  (brake  v a r i o u s flow r a t e s points,  which  mean of  effective pilot  diesel.  The  of  load  279 kPa)  with  apparent  ignition  may be i d e n t i f i e d as t h e p o i n t s where t h e c u r v e s  s t a r t r i s i n g , agree q u i t e w e l l pressure-crank  pressure  low  angle t r a c e .  with  those  observed  The i g n i t i o n d e l a y  from  the  i s i n c r e a s e d as  9TI  Straight diesel operation  LP  dual-fuel operation  bmep - 279kPa Ol QJ  (21% diesel)  714 kPa  TO T  .  bmep-279kPa 714kPa  o  (18% diesel)  "a ^ to  QJ LO c-)  ro QJ QJ  CO  cr  Oi CO  LU o*  QJ — t- a ro 1  co  o  - < ^ ^ . ^ - ^ V - ~T  C7>^p^  a I  -I -IU.O  tdc  1  I0.Q  1—  50.0  30.0  Crank Figure  1  Rngle  fdeg  5.14 - C o m p a r i s o n o f R a t e o f E n e r g y R e l e a s e Operation  f  flTDCJ  o  r  Straight  Diesel  and  Dual-Fuel  Figure  5.15  - Comparison Operation  of  Cumulative  Energy  Release  for  Straight  Diesel  and  Dual-Fuel  to  CD .  cn QJ  \  bmep - 279kPa  oo -=r  ( 3 3 % full load)  CD  13.5 V.  diesel  20.6%  diesel  rr,  32.0%  diesel  100%  diesel  O J D_ ir, C R-)  •o  ,1  I  I  -10 0  Figure  5.16  tdc  I 10  -°  - Rate o f Energy  I  Crank Release  I  30.0  Angle of Dual-Fuel  I  I 50  I  1  -°  7  0  0  (deg RTDC) Operation  at Various  Pilot  D i e s e l Flow  Rates  119  much as 2 degree C A . decreased first  from  as the  flow  100 t o 13.5 percent  rate  of  pilot  diesel  of t o t a l energy i n p u t .  stage of combustion i n s t r a i g h t d i e s e l o p e r a t i o n  about  70 percent  in a  higher  peak  of  consumes  total  energy  Further  d i e s e l r e s u l t s i n lower and wider peaks.  input  reduction  with  of  F i g . 5.18 shows  the f r a c t i o n of f u e l burned a t d i f f e r e n t p i l o t q u a n t i t i e s . operation  A  f o r r a t e of energy r e l e a s e w i t h no  i n d i c a t i o n of t h e two-staged c o n b u s t i o n . pilot  The  of t h e d i e s e l energy i n p u t (see F i g . 5.17).  r e d u c t i o n of p i l o t d i e s e l t o 32 percent results  is  The  low p i l o t d i e s e l flow r a t e shows a l a r g e amount  of unburned f u e l .  The amount of unburned f u e l d e c r e a s e s as the  flow r a t e of p i l o t d i e s e l i s i n c r e a s e d . F i g . 5.19 operation  shows t h e r a t e of energy r e l e a s e f o r a h i g h  (brake mean e f f e c t i v e p r e s s u r e  of 571 k P a ) . R e d u c t i o n  of p i l o t d i e s e l flow r a t e appears t o i n c r e a s e d e c r e a s e t h e maximum r a t e of energy  release  shown  combustion o c c u r s ratios.  The  i g n i t i o n delay and  release.  The  cumulative  i n F i g . 5.20 i n d i c a t e s t h a t a t t h i s l o a d  i n two  small  energy  load  stages  at  a l lpilot  diesel  energy  second-stage combustion i n h i g h l o a d d u a l -  f u e l o p e r a t i o n seems t o be t h e consumption, i n t h e main chamber, of t h e unburned and/or p a r t i a l l y burned f u e l r e m a i n i n g flame p r o p a g a t i o n  i n the f i r s t  stage.  from  the  CD  bmep - 279kPa ( 3 3 % full load)  LO CO  T3.5% 20.6% 32.0% 100%  .—. cn ^  CD  CO  diesel diesel diesel diesel  in  (/) CM' ro CD  "ai ai  CN  ai  ro o  a> cu >  m_  +->  rd  3 LP c6  CD  LP CD  •10.0  Figure  5.17  tdc - Cumulative  10.0  30.0  Crank Energy  Release  Angle o f Dual-Fuel  "I  1  1  70.0  50.0  (deg  RTQC)  Operation  at Various  Pilot  Diesel  Flow  Rates  Figure  5.18  - Fraction of  Fuel  Burnt  i n Low  Load  Dual-Fuel  Operation  ZZI  CD LO CO  CD LP -10.0  Figure  5.20  tdc  10.0  Crank  - Cumulative Diesel  30.0  Energy Release Flow Rates  50.0  Angle  (deg FITDC)  of Dual-Fuel  Operation  at Various  70 0  Pi  124  5.3.2 E f f e c t of R e s t r i c t i n g I n t a k e A i r F i g . 5.21  shows  the  rate  of energy r e l e a s e f o r low l o a d  o p e r a t i o n w i t h and w i t h o u t a i r r e s t r i c t i o n . restriction degrees.  of  intake  a i r lengthens  It  ignition  delay  by 1-2 of  r e s t r i c t i o n of a i r .  the i n t a k e a i r i s r e s t r i c t e d a drop i n the p r e s s u r e a t t o p  dead c e n t r e i s n o t i c e d . there  appears  from  temperature.  This  temperature  would  A r a t h e r s u p r i s i n g phenomenon  the  calculation  i s contrary drop  as  b a s i s used by L e w i s ( l 9 5 3 )  to  the  to the  be  an  delay  since  the temperature i s change  in  the-chemical  delay  change i n p h y s i c a l d e l a y .  This  I t seems t h a t the  would  F i g 5.23  and  increase  corresponding  operation  that  F i g . 5.22 shows t h e c u m u l a t i v e  F i g . 5.24.  load  of  energy  rate  flammability.  is  The o p e r a t i o n a t the brake load)  exhibits  a  of energy r e l e a s e when t h e  The g a s - a i r m i x t u r e i s 0.606  operation  s t r e n g t h f o r the  i n equivalence  ratio.  v a l u e i s s l i g h t l y above the p r e v i o u s l y mentioned v a l u e limit  the  operations.  i n maximum  intake a i r i s r e s t r i c t e d .  change i n  suggest  mean e f f e c t i v e p r e s s u r e of 571 kPa (67% f u l l radical  the  more s e n s i t i v e t o t h e  The e f f e c t of a i r r e s t r i c t i o n f o r h i g h in  the  d e l a y would be shortened i f  i s probably  release f o r the corresponding  shown  that  in  i n e x p l a i n i n g the i n c r e a s e i n i g n i t i o n  increased.  ignition  that  p r e s s u r e d r o p s , which was t h e  i n c r e a s e i n i g n i t i o n d e l a y i s not the r e s u l t of chemical  is  increase  assumption  d e l a y when the r e s t r i c t i o n of a i r i s imposed.  lower  that  Table 5.2 i l l u s t r a t e s t h e temperature and p r e s s u r e  m i x t u r e a t t o p dead c e n t r e w i t h and w i t h o u t When  indicates  This  f o r the  Thus the sudden i n c r e a s e i n t h e  CO  . .  bmep - 279 kPa, a i r r e s t r i c t e d (5 = 0. 400) , 14.5% d i e s e l a i r u n r e s t r i c t e d (d = 0.364) , 279 kTa, bmep 13.5% d i e s e l bmep - 143 kPa, a i r r e s t r i c t e d (c5 = 0. 308) , 20.9% d i e s e l a ir u n r e s t r i c t e d (<E 0.279), 143 kPa, bmep 19.5% d i e s e l  co  g  cm a QJ  \  1  • \  9  0  ro _  g  crj  ~J  g  QJ ^ . LO <=> ro QJ  >~  CJ) CU CD  c ;. UJ <=>  U-  o QJ ~. .  +-> C D  ro  cc  co CD  CO CD I  CD I  tdc  -10.0  Figure  5.21  10.0  Effect  Crank  Angle  o f R e s t r i c t i n g Intake  70.0  50.0  30.0-  (deg flTD-C) A i r on Rate  o f Energy  Release  LOAD (kPa)  AIR RESTRICTION  143  unrestricted  19.5  0. 279  968  4810  0.0631  143  restricted  20.9  0.308  999  4 370  0.0555  279  unrestricted  13.5  0.364  951  4860  0.064 8  279  restricted  14 .5  0.400  1010  44 70  0.0564  4 29  unrestricted  15 .0  0.437  944  5000  0.0673  429  restricted  15 . 3  0.483  1010  4680  0.0586  571  unrestricted  10.2  0.526  955  5210  0.0692  571  restricted  10 . 7  0.606  1010  4 7 8.0  0.06 01  Table  5.2  - Effect at  Top  FRACTIONAL D I E S E L ENERGY INPUT (%)  o f Intake Dead  *  gas  T  tdc  ™  A i r R e s t r i c t i o n on M i x t u r e  Center  P  t  d  c  (kPa)  Temperature  # OF MOLES OF INTAKE MIXTURE  CD  bmep - 279 k P a ,  a i r r e s t r i c t e d (cD = 0 . 4 0 0 ) , 14.5% d i e s e l a i r u n r e s t r i c t e d (cB = 0 . 3 6 4 ) , 13.5% d i e s e l a i r r e s t r i c t e d (<5 = 0 . 3 0 8 ) , 20.9% d i e s e l a i r u n r e s t r i c t e d (cB 0.279), 19.5% d i e s e l g  LO  bmep - 279 k P a ,  CO  g  bmep - 1 4 3 k P a ,  3  g  bmep - 1 4 3 k P a ,  CO  g  CO ^ </> CM OJ CO cc CD CM'  sco c  LO  CO  > +J  •r— I 3  E  CD —'  o LO  CD CD CD CD •10.0  tdc  10.0  1  Crank Figure  5.22 - E f f e c t  of Restricting  1 30.0  Angle Intake A i r on  70.0  50.0  fdeg  flTDC)  Cumulative  Energy  Release  -0.1  -0.G3  Rate of  0.03 _] I  0.1 I  I  Energy 0.16 I  I  Release  0.23 I I  (kJ  0.3 i  I  / aeg)  0.36 I I  0.43 I 1  Cu—|  o  CD  O •J  ID n  in •  ro  Gj  nf  CD  If  i  a  tf If "3 I  I  cn  QJ  CO  $  5  QJ  QJ  5 Q)  Q) t ( QJ P> O J i — i QJ O P- O P- Ul p-In p• f ( • 1-1 • t-l • f< ui o <#> i-i o'P CP i-( M C CD o'P C  u-i  a ZD  •V---  cn  Ch  :ted  Oi cn ^ a P- CD £' R"aP- fDR cn Pft(D cn a ) c n tn p- ifl rr n> o cn nP pP" P-  rb o -3  I  9*  il o cn o -—' iD —  CD  821  1  CD Ho<  O  ft -r-  el II  II  o •  NJ  o  .J>  00  CO  '  ff et  cQ  n O •  CO  0.5 L_  o  Ln  CD  CO  LO CM* 01 (O  * CD cn c  >  •r-  429  a i r unrestricted (c6 =0 . 4 3 7 ) , 15.0% diesel 429 k P a , a i r r e s t r i c t e d (« = 0 . 4 8 3 ) , 15.3% diesel 571 k P a , a i r u n r e s t r i c t e d (ffi = 0 . 5 2 6 ) , 10.2% diesel 571 k P a , a i r r e s t r i c t e d (I> = 0 . 6 0 6 ) , 10.7% diesel  —  g  g  CD  +-> —' UJ  g  E  3  O  kPa,  g  LO  CD CD in  CD  •10.0  Figure  tdc  5.24  - Effect  10.0  Crank of  Intake  1—  30.0  Angle  A i r R e s t r i c t i o n on  70.0  50.0  (deg  ATDC)  Cumulative  Energy  Release  130  maximum r a t e of energy r e l e a s e seems t o be the r e s u l t air  ratio  on p r o p a g a t i o n  of  fuel-  of a flame through a premixed g a s - a i r  mixture.  5.3.3 E f f e c t of V a r y i n g  I n j e c t i o n Timing  F i g . 5.25 and F i g . 5.26 show t h e e f f e c t i n j e c t i o n t i m i n g a t low l o a d . 10 degree C A .  results  i s more d i s t i n c t .  t i m i n g of 12.3  and  advancing  17.3  the  Advancing the i n j e c t i o n t i m i n g by  i n the maximum r a t e of energy  o c c u r i n g a t t o p dead c e n t e r . combustion  of  For t h i s t i m i n g the  second  For t h e o p e r a t i o n s w i t h  degree C A . BTDC  the  release stage  injection  combustion  is  t a k i n g p l a c e o n l y a f t e r t h e p i s t o n has s t a r t e d moving downwards, thus  assisting  chamber. CA.  t h e flow of m i x t u r e  from prechamber t o the main  For the o p e r a t i o n w i t h i n j e c t i o n t i m i n g of 22.3 degree  BTDC, the combustion takes p l a c e when the p i s t o n i s n e a r l y  motionless,  and  the  second  stage  combustion  would  be  more  distinctive. The  effect  of  r e t a r d i n g i n j e c t i o n timing at high load i s  shown i n F i g 5.27 and F i g . 5.28. maximum retarded.  rate  of  Again  S i g n i f i c a n t reduction  i n the  energy r e l e a s e i s observed when t h e t i m i n g i s the  two-staged  combustion  characteristics  become l e s s d i s t i n c t i v e as the t i m i n g i s r e t a r d e d .  LTJ CD  bmep - 279 kPa, 20% d i e s e l  CO  . . "3  i n j e c t i o n a t 12.3 17.3 22.3  QJ -a . \  CD CO  BTDC BTDC BTDC  j  _l  -10.0  Figure  ,  tdc  5.25 - E f f e c t  ,  (  10.0  Crank o f Advancing  , 30.0  Angle Injection  r —  ,  ,  50.0  r—  70.0  (deg ATDCJ Timing  on Rate  o f Energy  Release  Cumulative -0.5  CD  0.0  _l  0.5 I  I  1.0 I  I  Energy 1.5 I  l  Release 2.0 i  i  2.5 i  (kJ) I  3.0 I  3.5 I  I  ' i  O  n  CD CD  o QJ  ID rj . to co i , a  70  a 3D  '  a  tr 3  1 1 1 ! i i  CL  fD TI  1  1  1  hj.  M  i_J. -J "'3  g  ?]  rt H0 3 0) rt M  h-  •  •  to  CO  —1  1  CO  M  .  CO  CD 03 UJ i-3 t-3 t-3  a  a a a o n n  ZEI  <£>  13  ^ O <#>  a  ro  cn  (D h1  4.0 i  C3  LO  brep - 571 kPa, 10% d i e s e l  CO tzn QJ  b  i n j e c t i o n a t 12.3 10.3 8.3  "TZJ  CD  BTDC BTDC BTDC  -I  CD  QJ ° ? . LO ro QJ  >. P  CO OO  cn t o c —. LU <=)  CD  QJ —; •M  ro  CO  CD OO CD  I  -10.0  tdc  10.0  30.0  Crank Figure  5.27 - E f f e c t  o f Retarding  Angle  Injection  Timing  50.0  (deg o n Rate  70.0  flTDC) o f Energy  Relea  CD  LD CO  CD  LP  -10.0  tdc  10.0  30.0  Crank Figure  5.28  - Effect  of Retarding  50.0  Angle  Injection  (deg Timing  on  70.0  flTDC)  Cumulative  Energy  Release  135  CH.VI C o n c l u s i o n s and Recommendations  6.1  Conclusions  Safe o p e r a t i o n of a prechamber fuelling  with  natural  cylinder pressure. pressure  of  gas  Even  i s severely half  load  engine limited  with by  t h e maximum  dualmaximum  cylinder  d u a l - f u e l o p e r a t i o n i s as h i g h as t h a t of s t r a i g h t  d i e s e l operation at f u l l pressure  at  diesel  load.  The e x c e s s i v e  maximum  cylinder  i s a s s o c i a t e d w i t h t h e h i g h r a t e of energy r e l e a s e by  combustion which takes p l a c e w i t h i n a n e a r l y homogeneous g a s - a i r mixture.  The maximum c y l i n d e r p r e s s u r e , as w e l l as t h e r a t e  cylinder  pressure  rise,  can  be  reduced  to  a s a f e l e v e l by  r e t a r d i n g the i n j e c t i o n t i m i n g by about 4 t o 6 degrees of angle.  crank  The change i n t h e r m a l e f f i c i e n c y due t o t h e r e t a r d a t i o n  i s s m a l l ( l e s s than 0.5 p e r c e n t 67 p e r c e n t of f u l l also  of  load).  with  4 degree  retardation at  R e s t r i c t i n g t h e i n t a k e a i r can reduce  t h e maximum c y l i n d e r p r e s s u r e , but t h i s r e s u l t s i n h i g h e r  maximum r a t e of c y l i n d e r p r e s s u r e  rise.  S t a b l e d u a l - f u e l o p e r a t i o n r e q u i r e s s u f f i c i e n t f l o w r a t e of pilot diesel fuel; insufficient results  amount, of  pilot  diesel  i n e r r a t i c operation with m i s f i r e d c y c l e s .  fuel  The minimum  p i l o t d i e s e l f u e l r e q u i r e d i n o r d e r t o ensure a s t a b l e o p e r a t i o n is typically  8  to  15  depending on engine l o a d .  percent  of  the t o t a l  energy  input,  136  Dual-fuel  operation  at  p a r t l o a d showed g e n e r a l l y  f u e l consumption than t h a t of s t r a i g h t apparent  energy  diesel  release a n a l y s i s revealed  higher  operation.  The  t h a t the h i g h e r  fuel  consumption r a t e i s m a i n l y due t o gas s u r v i v i n g unburned t h r o u g h the. combustion chamber.  The main cause of t h i s poor  i s weak g a s - a i r m i x t u r e s t r e n g t h . rates  reduces  i n p i l o t d i e s e l flow  the amount of unburned gas and thus improves the  f u e l consumption r a t e .  The dependence of t o t a l f u e l  r a t e on p i l o t d i e s e l flow  rate  mixture  concentration.  pressure  ( t o p r e v e n t surge)  restriction  Increase  combustion  was  is  less  with  consumption  higher  gas-air  With r e s t r i c t i o n on t u r b o c h a r g e r i n l e t  possible  less in  than  about  10  percent a i r  the t e s t s c o n d u c t e d ; t h i s showed  some improvement (perhaps one p e r c e n t ) on f u e l consumption r a t e . Advancing i n j e c t i o n t i m i n g showed no s i g n i f i c a n t e f f e c t on  fuel  consumption r a t e . The full  fuel  load  consumption r a t e d u r i n g d u a l - f u e l o p e r a t i o n  approached  Extrapolated  beyond  that full  of  straight  load  diesel  diesel  near  operation. the  fuel  would become lower  than  The combustion c h a r a c t e r i s t i c s of s t r a i g h t d i e s e l and  dual-  consumption r a t e of d u a l - f u e l o p e r a t i o n  operation,  t h a t of s t r a i g h t d i e s e l o p e r a t i o n .  fuel  operation  differ  in  that  in  the former the combustion  c o n s i s t s m a i n l y of a u t o - i g n i t i o n of d i e s e l f u e l , whereas i n  the  l a t t e r the combustion i s c a r r i e d out by the p r o p a g a t i o n of flame fronts.  T h i s d i s t i n c t i o n was c l e a r l y e x h i b i t e d i n the a n a l y s i s  of apparent energy showed  a  release,  two-staged  where  combustion  straight and  diesel  dual-fuel  operation  operation  a  137  s h o r t e r , s i n g l e - s t a g e d combustion.  138  6.2 Recommendations  • Without  d i f f i c u l t modifications  the c u r r e n t  c o n v e r t e d i n t o a d i r e c t - i n j e c t i o n engine. converted  engine  would  lead  prechamber and d i r e c t - i n j e c t i o n  • Further studies at d i f f e r e n t  to  engine  turbocharger  be  F u r t h e r t e s t s on t h i s  comparative  study  between  engines.  engine speeds a r e r e q u i r e d .  • F u r t h e r study of t h e e f f e c t of r e s t r i c t i n g a i r i n t a k e the  can  without  may show some improvement i n f u e l consumption  at low l o a d s .  • Exhaust  gas a n a l y s i s would p r o v i d e some important  such as t h e lower l i m i t of f l a m m a b i l i t y .  information  139  BIBLIOGRAPHY  1. 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LYN, W.T., " C a l c u l a t i o n of the E f f e c t of Rate of Heat Release on t h e Shape of C y l i n d e r - P r e s s u r e Diagram and C y c l e Ef f i c i e n c y " , P r o c . I n s t . of Mech. Eng., No. 1,pp34, 1960/61. 28. LYN,W.T., "Study of B u r n i n g Rate and Nature of Combustion i n D i e s e l E n g i n e s " , N i n t h I n t e r n a t i o n a l Symposium on Combustion, Academic P r e s s , New York, N.Y., p p l 0 6 9 - l 0 8 2 , 1962. 29. LYN,W.T., SAMAGA,B.S., BOWDEN,C.M., "Rate of Heat R e l e a s e i n High-Speed I n d i r e c t - I n j e c t i o n D i e s e l E n g i n e s " , P r o c . Inst. Of Mech.Eng., V o l . 184, P t . 3 J , pp122, 1969/70.  141  30. MITCHELL, R.W.S., and WHITEHOUSE,N.D., The Development and Performance of a Range of Dual F u e l E n g i n e s , Canadian M i n i n g and M e t a l l u r g i c a l B u l l e t i n , 1955 31. Moore, N.P.W., and MITCHELL,R.W.S., Combustion i n Dual F u e l E n g i n e s , J o i n t Conf. on Combustion, ASME/Inst. of Mech. Eng. pp300 1955. 32. MURAYAMA,T,MIYAMOTO,N,and FUKAZAWA,S, Study on t h e Performance o f a M u l t i f u e l Engine, Vol.14 N.67, p76-83, 1971  An E x p e r i m e n t a l Bull. JSME  33. OBERT,E.F., I n t e r n a l Combustion Engines and A i r P o l l u t i o n , 3rd ED., Harper & Row, 1973 34. O'NEAL,. G.B., "The D i e s e l - G a s D u a l - F u e l E n g i n e " , Symposium on Nonpetroleum V e h i c u l a r F u e l s I I I , A r l i n g t o n , Virginia, Oct. 12-14, 1982. 35. ROUGHTON, J.H., " D u a l - F u e l E n g i n e s " , No. 4064,pp34-8, May, 1970.  S u r v e y o r , V o l . 135,  36. SIMONSON, J.R., "Some Combustion Problems of the D u a l - F u e l Engine", E n g i n e e r i n g , v o l . 178, p.363, 1954. 37. SIMONSON, J.R., "An A n a l y s i s of D u a l - F u e l Combustion Proceses i n a Compression I g n i t i o n E n g i n e " , Ph.D T h e s i s , London U n i v e r s i t y , 1955. 38. STEVEN. G., " O p e r a t i n g Problems of the D u a l - F u e l E n g i n e " , Power E n g i n e r r i n g , March, 1953. 39. TAYLOR, C.F., "The I n t e r n a l Combustion Engine i n Theory and P r a c t i c e " , V o l . 1 & 2, M.I.T. P r e s s , 1982. 40. VAN WYLEN, G.J., SONTAG, R.E., Fundamental Thermodynamics", 2nd ED., John W i l e y & Sons, 1978.  of C l a s s i c a l  41. WATSON, N.,KAMEL, M., "Thermodynamic E f f e c i e n c e e v a l u a t i o n of an I n d i r e c t I n j e c t i o n D i e s e l E n g i n e " , SAE Paper No. 790039, Feb-Mar 1979. 42. WHITEHOUSE, N.D., STOTTER, A., GOUDIE, G.D., PRENTICE, B.W., "Method of P r e d i c t i n g Some A s p e c t s of Performance of a D i e s e l Engine U s i n g a D i g i t a l Computer", P r o c . I n s t . of Mech. Eng., V o l . 176, No, 9, 1962. 43. WHITEHOUSE, N.D., WAY, R., Rate of Heat R e l e a s e i n D i e s e l Engines and I t ' s C o r r e l a t i o n w i t h F u e l I n j e c t i o n Data", Proc. I n s t . Mech. Eng., V o l . 184, P t . 3 J , p p l 7 , 1969/70.  142  APPENDIX  Load  A - CALIBRATION  CURVES  Sensor  o o"  o o' o  o o'  00  o o'  T3  O  •J  O  (mV)  Voltage  *  slope  -  22.2  N/mV  143  Air  Flow  Element  144  Gas  Flow  Element  Differential  Pressure  (kPa)  145  146  APPENDIX  B - COMPUTATION  OF  INDICATED  MEAN  EFFECTIVE  PRESSURE  Definition  An as  indicated  that  exerted work  mean  effective  theoretical  constant  during  power  equal  each  P V  dV  pressure  stroke  to the i n d i c a t e d  J  pressure,  =  imep,  which  i s defined  c a n be  of the engine  to produce  work:  P. „ AV ind  l where  P  - cylinder  pressure  P. , - i n d i c a t e d ind - pressure,  computed  effective  according  V^  - V at the beginning the cycle  pressure,  to the  effective  - cylinder  volume of  V a t t h e end o f t h e bdc  mean  mean imep  V  -  Indicated  imagined  cycle  tdc  in this  project,  was  following: (P.  +  2  P.,,) 1  +  1  ( V . „  i+1  - V.)  r  ^ ind ( V  where  bdc  V  tdc  )  P^,  are cylinder  volume  at i ^ t  1  pressure  stage,  stage  corresponds  crank  angle  and  each  to a degree  throughout  a  and  of  cycle.  147  148  APPENDIX  C - COMPUTER  PROGRAM  ACQUISITION  FOR  CYLINDER  PRESSURE  DATA  149  Listing 1 2 3 4 5 6 7  e9  10 1 1 12 1 3 1 4 1 5 1 6 1 7 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 4 1 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58  of APP.PR0G2 a t 22:10:05 on APR C C C  Acquires  data  11, 1984 f o r CCid=AFPH  from D i e s e l  Engine  EXTERNAL EXTERNAL EXTERNAL  QTQIO GETADR ASNLUN  INTEGER INTEGER REAL  L I S T C 3 0 0 2 ) , IDAT(3002), 1PARM(6) YES, NO, ANS, IPARR(5), IBDC(3) LOAD, PMEAN(721), VOLUME*5)  C  C YES NO SCALE NPOINT NPCYC NPCYCE NPCYCS NPCY2 STROKE ARM ROD VCLEAR PTAREA NPC1 FNPC1 NPCY3 RDPDEG PTHR PMINRF STHR  C 5  =  1 = 0 = -32768.0 = 3001 = 720 = 750 = 700 = 360 = 6.0 = 3.0 = 9.595 = 6.444 = 3.1416* ( 4 . 7 5 / = 721 - FLOAT(NPC1) = NPCY2 + 50 = 0.0174533 = 400.0 = 14.7 = 0.6  2.0)**  2  DO 5 1 = 1 ,3002 IDAT(I) = 0 CONTINUE  C 6  DO 6 1=1,NPC1 PMEAN(I) = 0.0 CONTINUE CALL ASNLUN(3, 'NI', 0) CALL ASSIGN*1, 'PAR2.DAT')  C READ(1,100) CLOCK DWELL = 1. / CLOCK HERTZ = 1 . / XRATE(DWELL, I RATE, IPRSET, CALL CLOCKB(I RATE, IPRSET, 1, IND, 1) DELT = 1. / HERTZ WRITE(5,200) IND, HERTZ C READ(1,101) READ(1,102)  NCHAN NDPCH  C  c c  NDTOT = NPOINT ISTRT = 1 I LAST = NDTOT + 1 read in port address READ(1,103) LIST(1)  1)  ISTAT(2)  150  Listing 59 60 61 62 63 64 65 66 67  6B  69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 1 02 103 104 1 05 106 107 108 109 11 0 11 1 1 12 11 3 1 14 1 15 1 16  of APP.PROG2 a t 22:10:05 on APR  c  c  c  10  11  c c  c c  20  c  c c c  c  11 ,  1 984 f o r CCid=AFPH  r e a d i n scan i n s t r u c t i o n s DO 10 I=2,NCHAN+1 READ(1,103) L1STU) CONTINUE f i l l the r e s t of scan l i s t by r e p e a t i n g DO 11 I=NCHAN+2,ILAST L I S T ( I ) " = LIST(I-NCHAN) CONTINUE r e s e t s e r i e s 500 BUS IPARMC2) = 2 CALL GETADR(IPARM(1), IDAT) CALL WTQ10("1002,3,10,1,1 STAT,IPARM,IDS) WRITE(5,201) WRITE(5,202) I S T A T ( I ) , I S T A T ( 2 ) , IDS IRSA = 1 w r i t e scan l i s t to RAM, read back and c h e c k IPARM(2) = (ILAST-ISTRT+1) * 2 IPARM(3) = IRSA CALL GETADR(IPARM(1),LI ST(1 START)) CALL WTQIO("400,3, 10, 1 ,I STAT,IPARM,IDS) read back CALL • GETADR(IPARM(1), I DAT(ISTRT)) CALL WTQIO("1000,3,10,1,1 STAT,IPARM,IDS) p r i n t any d i s c r e p a n c i e s I ERR = 0 DO 20 1 = 1STRT,I LAST IF (IDAT(I) .EQ. L I S T ( I ) ) GO TO 20 I ERR = I ERR + 1 WRITE(5,203) LI ST(I ),I DAT(I) CONTINUE WRITE(5,204 ) I ERR WRITE(5,202) I S T A T ( l ) , I S T A T ( 2 ) , IDS IF (I ERR .GT. 0) GO TO 999 a c q u i r e data IWCT = NDTOT + 1 CALL I DATE(ID 1 , ID2, ID3) WR1TE(5,205) ID1, ID2, ID3 calibration PCPPSI CHMUPV PCPMU GAIN C1P  of P r e s s u r e Measurement  = = =  0.830 1000.0 1.415 =1.0 = CHMUPV * PCPMU / PCPPSI / SCALE * GAIN  DO 600 1600=1,100 WRITE(5,270) READ(5,170) SPEED FREQRQ = SPEED / 60.0 / 2.0 * FLOAD(NPCYC) * 2 DWELL = 1. / FREQRQ HERTZ = 1. / XRATE(DWELL, I RATE, IPRSET, 1) CALL CLOCKBCIRATE, IPRSET, 1, IND, 1) DELT = 1. / HERTZ * 2 DTPDEG = DELT WRITE(5,200) IND, HERTZ NCYCLE =10  151  Listing  of APP.PROG2 at 22:10:05 on APR  1 7 1 8 1 9  20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 46 49 50 51  52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 66 69 70 71 72 73 74  610  C  11, 1984 f o r CCid=AFPH  WRITE(5,271) NCYCLE READ(5,171) NCYCLE IPMAX = 0 FNCYC = FLOAT(NCYCLE) NSET = 1 DO 610 1610=1,NPC1 PMEAN(1610) = 0.0 CONTINUE PMAX0 = 0.0 DPDTM0 = 0.0 RPMIN0 = 0.0 RIMEP0 = 0.0 SUMRP = 0.0 SUM2RP = 0.0 SUMIM = 0.0 SUM2IM = 0.0 SUMPX = 0.0 SUM2PX = 0.0 SUMPN = 0.0 SUM2PN = 0.0 SUMDN = 0.0 SUM2DN = 0.0 WRITE(5,269) READ(5,170) PINTAK PINTAK >= PINTAK + 14.7 WRITE(5,210) READ(5,110) CR DO 650 M650=1,500 IF (NSET .GT. NCYCLE) GO TO 651 CALL GETADR(I PARK(1 ) , I DAT) IPARM(2) = IWCT *2 IPARM(3) = IRSA CALL WTQIOC3001 ,3,1 0, 1 ,I STAT,IPARM,IDS)  C  682  681  680 663  MB = 3 MF =751 DO 680 M680=1 ,2 DO 661 M=MB,MF,2 S = IDAT(M) S = ABS(S/SCALE) IF (S .LT. STHR) P = IDAT(M+359) P = P * C1P IF (P .LT. PTHR) IBDC(1) = M GO TO 683 CONTINUE MB = M + 680 MF = MB + 80 GO TO 680 CONTINUE CONTINUE GO TO 650 CONTINUE INDXBD = 2 MB = IBDC(1) + 680 MF = MB + 80  GO TO 681 GO TO 68 2  152  Listing 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232  of APP.PR0G2 a t 22: 10:05 on APR  686 685  621  625 626  1 1  632 914  1 1, 1984 f o r CCi d=AFPH  DO 685 M685=1,2 DO 686 M=MB,MF,2 S = 1DAT(M) S = ABS(S/SCALE) IF (S .LT. STHR) GOTO 686 IBDC(INDXBD) = M MB = M + 680 MF = MB + 80 INDXBD = INDXBD + 1 GO TO 685 CONTINUE GO TO 650 CONTINUE IDIFFA = IBDC(2) - I B D C ( 1 ) IDIFFB = IBDC(3) - IBDC(2) MB = IBDC(2) + 681 MF = MF + 80 PMIN = 0.0 CONTINUE IDIFF = IDIFFA + IDIFFB RPMIND = 60.0 / (FLOAT(IDIFF) * DELT) * 4.0 MM = IBDC(3) - 81 DO 625 M= 1 ,40 PM = I DAT(MM) PMIN = PMIN + PM MM = MM + 2 CONTINUE PMIN = PMIN / 40.0 *C1P CONTINUE IBDC1P = IBDC(1) - 1 IBDC3P = IBDC(3) - 1 PMAX = 0.0 DPDTMX=0.0 RIMEP =0.0 THETA =-180.0 DTHETA = 720. / FLOAT(IDIFF) * 2.0 DO 632 J1=IBDC1P,1BDC3P,2 PJ1P1 = IDAT(J1+2) PJ1 IDAT(J1) PJ1P1 - PJ1P1 * C1P - PMIN + PINTAK PJ1 = PJ1 * C 1 P - PMIN + PINTAK DPDT = ABS((PJ1P1-PJ1) / DELT) * DTPDEG IF (DPDT .GT. DPDTMX) DPDTMX = DPDT RAD1 = THETA * RDPDEG RAD2 = (THETA + DTHETA) * RDPDEG X1 = -ARM * COS(RADI) SQRT(ROD*ROD - (ARM * SIN(RADI)) ** 2) X2 = -ARM * COS(RAD2) ~ SQRT(ROD*ROD - (ARM * SIN(RAD2)) ** 2) PAVER = (PJ1 + PJ1P1) / 2.0 RIMEP = RIMEP + PAVER / STROKE * (X2 - X1) I F (PJ1 .GT. PMAX) PMAX = PJ1 THETA = THETA + DTHETA CONTINUE WRITE(5,914) IBDC1P, IBDC3P FORMAT*' C y c l e l i e s between ',15,' < > ',15,' d e g r e e s WRITE(5,272) NSET, ID1FF, RPMIND WRITE(5,273)  ')  153  Listing 233 234 235 236 237 2 38 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 2 54 2 55 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 2B5 286 287 288 289 290  of APP.PROG2  a t 22:10:05 on APR  11, 1984 f o r CCid=AFPH  WRITE(5,274) PMAX, PINTAK, RIMEP, DPDTMX C  637  650 651  WRITE(5,279) READ(5,120) ANS IF (ANS .EQ. NO) GO TO 650 FI BDC 1 «= FLOAT(IBDCIP) DO 637 JI=1,721 F J J 1 - F L O A T ( J I - l ) / DTHETA * 2.0 + FIBDC1 INDX - ( F J J 1 / 2.0) INDX - INDX * 2 RINDX = (FJJ1 - FLOAT(INDX)) / 2.0 PINDX = IDAT(INDX) PINDX1 = IDAT(INDX+2) PINDX = PINDX *C1P - PMIN + PINTAK PINDX1 = PINDX1 * C1P - PMIN + P.1NTAK P = PINDX * RINDX * (PINDX1 - PINDX) PMEAN(J1) = PMEAN(J1) + P / FNCYC CONTINUE PMAX0 = PMAX0 + PMAX RIMEP0 = RIMEP0 + RIMEP DPDTM0 = DPDTM0 + DPDTMX RPMIN0 = RPMIN0 + RPMIND SUMRP = SUMRP + RPMIND SUM2RP « SUM2RP + RPMIND*RPMIND SUMIM « SUMIM + RIMEP SUM2IM = SUM2IM + RIMEP*RIMEP SUMPX n SUMPX • PMAX SUM2PX - SUM2PX + PMAX*PMAX SUMPN • SUMPN + PMIN SUM2PN = SUM2PN + PMIN*PMIN SUMDP = SUMDP + DPDTMX SUM2DP = SUM2DP + DPDTMX*DPDTMX NSET = NSET + 1 CONTINUE WRITE(5,299) GO TO 652 CONTINUE PMAX0 = PMAX0 / FNCYC DPDTM0 ' DPDTMO / FNCYC RPMIN0 « RPMINO / FNCYC RIMEPO « RIMEPO / FNCYC FNCYC1 = FNCYC - 1 IF (FNCYC1 .EQ. 0) FNCYC1=1 SDIMEP = SQRT((SUM2IM-SUMIM*SUMIM/FNCYC)/FNCYC1) SDPMAX •= SQRT((SUM2PX-SUMPX*SUMPX/FNCYC)/FNCYC1) SDPMIN «= SQRT( (SUM2PN-SUMPX*SUMPN/FNCYC )/FNCYC 1 ) SDDPDT = SQRT((SUM2DP-SUMDP*SUMDP/FNCYC)/FNCYC1) SDRPM = SQRT((SUM2RP-SUMRP*SUMRP/FNCYC)/FNCYC1) WR1TE(5,275) WRITE(5,276) NCYCLE, SPEED, HERTZ WRITE(5,277) WRITE(5,27B) RPMINO, PMAXO, PINTAK, RIMEPO, DPDTMO WRITE(5,286) SDRPM, SDPMAX, SDPMIN, SDIMEP, SDDPDT  C 652  CONTINUE WRITE(5,290) READ(5,120) ANS I F (ANS .EQ. NO)  GO TO 998  154  Listing 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 3 08 309 310 311 312 313 314 315 316  of APP.PROG2 a t 22:10:05 on APR 600  CONTINUE  C C 998  317  318 3 19 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 34 0 •34 1 342 343 344 345 34 6 34 7 348  1 1, 1984 f o r CCi d = AFPH  661 660  670  CONTINUE WRITE(5,29l) READ(5,120) ANS IF (ANS •EQ. NO) GO TO 999 CALL ASSIGN(2, 'P.DAT') WRITE(5,292) READ(5,192) NDEG IPVDGM = NO INTERD = NDEG / 180 IF (IPVDGM .EQ. YES) INTERD = INTERD * 2 NDAT = NDEG / INTERD + 1 NDEG2 = NDEG / 2 ITDC = 181 IPBEG = ITDC - NDEG2 IPEND = ITDC + NDEG2 IF '(NEG .EQ. 720) IPBEG = 1 IF (NEG .EQ. 720) IPEND = 721 WRITE(2,700) PMAX = 0.0 NSKIP = 5 * INTERD DO 660 1660=IPBEG,IPEND,NSKIP JB = 1660 J F - 1660 + NSKIP -1 JL = 1 DO 661 J=JB,JF,INTERD P = PMEAN(J) IPARR(JL) = P JL = JL + 1 CONTINUE JLM1 = J L -1 WRITE(2,70l) (IPARR(LL), LL=1,JLM1) CONTINUE MINX = IPBEG - 181 MAXX = IPEND - 181 WRITE(2,702) IF (IPVDGM .EQ. YES)- GO TO 670 WRITE(2,703) NDAT, MINX, INTERD WRITE(2,704) MINX, MAXX WRITE(2,705) WRITE(2,706) RPMIN0 WRITE(2,707) GO TO 674 CONTINUE WRITE(2,710) THETA = MINX FINTER = FLOAT(INTERD) THETA = THETA - FINTER DO 662 I 662 = IPBEG,IPEND,NSKIP JB = 1662 J F = 1662 + NSKIP -1 JL = 1 DO 663 J=JB,JF,INTERD THETA = THETA + FINTER RAD = THETA * RDPDEG X «= ROD + ARM - ARM * COS(RAD)  155  Listing 349 3 50 351 352 353 354 355 356 357 356 359 360 361 362 363 364 365 366 367 366 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406  of APP.PROG2 a t 22: 10:05 on APR  1 1 , 1964  f o r C C i d = AFPH  - SQRT(ROD * ROD - (ARM * SIN(RAD)) ** 2) VOLUME(JL) = X * PTAREA + VCLEAR J L = JL + 1 CONTINUE JLM1 = J L - 1 WRITE(2,711) (VOLUME(LL), LL=1,JLM1) CONTINUE WRITE(2,702) WRITE(2,714) WRITE(2,715) WRITE(2,706) RPMINO WRITE(2,717) CONTINUE WRITE(2,708) WRITE(2,709) CONTINUE STOP  1 663 662  674 999 C C 100 101 102 103 110 120 150 170 17 1 180 192 195 C C  200 201 202 203 204 205 210 225 269 270 271 272 273 274 275 276 277 278 279  FORMAT(1X,F16.5) FORMAT(1X,I 2) FORMAT(1X,I 4) FORMAT(05) FORMAT(A5) FORMAT(11) FORMAT(F12.4) FORMAT(F7.2) FORMAT(I 2) FORMAT(F5.1,1X.F5.3,IX,F5.1) FORMAT(13,1X,I 2) FORMAT(II) FORMAT(IX,' IND CODE = ', 13,', F r e q u e n c y = ' , F 8 . 1 , ' Hz') FORMAT(1X,' SERIES 500 BUS RESET!!!',/) FORMAT(1X,' DRIVER COMPLETION CODE =',06,' (OCTAL)',/ 1, 1X,' LAST RESPONSE =',06,' (OCTAL)',/ 2, 1X,' DIRECTIVE STATUS =',06,' (OCTAL)',/) FORMAT(IX,'XXXX RAM ERRORXXXXXXXXXXXXXXXXXXXXXXXXXX',/ 1, 1X,' OUTPUT = ',05,' ; READ BACK = ',05,/) FORMAT(1X,' WRITE TO RAM AND READBACK COMPLETE*,I 3,' ERRORS', FORMAT(//,IX,' d a t e : ' , I 3,1X,I 2,IX,I 2,//) FORMAT(IX,'?? To s t a r t s c a n i n g , e n t e r RETURN!',$) FORMAT(1X,I5,2X,E14.6) FORMAT(IX,' >> > Enter Intake P r e s s u r e i n ( p s i ) : ' , $ ) FORMAT(IX," >> > Enter Engine Speed i n RPM:',$) FORMAT(1X,' I d e a l * o f C y c l e s i s ',12,', E n t e r d e s i r e d * 12 ', FORMAT(10X,' # of d a t a p o i n t s i n ',13,'th c y c l e i s ',14,/, 1 10X,' I n d i c a t e d E n g i n e Speed i s ',F6.1,' rpm') FORMAT(IX,' P max ( p s i ) P i n t a k e IMEP dpdt max ( p s i / d e g FORMAT(1X,3(2X,FB.3),4X,F11.2) F0RMAT(15X,' # of C y c l e s E n g i n e Speed Data a q u s i t F r e q ' , / , 1 15X,' (cycles) (rpm) (Hz) ') FORMAT(15X,BX,I 2,3X,5X,F6.1,4X,7X,F8.1) FORMAT(IX,' Mean: I n d i c a t e d Speed P max P i n t a k e IMEP 1 ' dPdt max ') FORMAT(IX,1IX,F8.3,5X,5(F11.2)) FORMAT(IX,' Do you want t o s e l e c t t h i s c y c l e ? ( 1 / 0 ) : ' , $ )  156  Listing 407 408 409 410 411 412 413 414 4 15 4 16 417 418 4 19 420 421 422 423 424 425 426 427  4 28 429  o f APP.PP0G2 a t 2 2 : 1 0 : 05 on APR 2 8 ~ 8 2 5 2 9 ? 9 7 9 299 7 00 710 701 7 11 7 02 "i*3 7;.4 7U 705  7 •, 5 706  707 7-.7 "0=  709  0 u 0 : 2 5  11, 1984 f o r C C i d = AFPH  F O R M A T ( 1 X , ' >> > E n t e r M.U. p e r V , p C p e r M.U., G a i n : ' , ? ) F O R M A T * I X , ' S t a n d . D e v L ' , F 8 . 3 , 5X , 5 ( F 1 1 . 3 ) ) F O R M A T ( / / , ? ? ? ? ? ? To R e r u n e n t e r l o r 0 ' , S ) FORMAT(1X,'To save d a t a f o r p l o t , E n t e r 1 o r 0 : ' , S ) FORMAT!1X,'Enter Crank A n g l e Range 13:',$) F O R M A T * I X . ' D o y o u w a n t a P-V d i a g r a m ? Enter l or 0 : ' , S ) FORMAT*' <======> C y c l e N O T f o u n d . <======> ') FORMAT(1X,'EN PRES f) F O R M A T * I X , ' E N VOL &') FORMAT*IX,5(15,IX),'I') FORMAT*1X,5(F5.1,1X),'') FORMAT(IX,';') F O R M A T ( I X , ' E N A N G L SHOR ' , 1 3 , I X , 1 4 , I X , 1 2 ) F O R M A T ( 1X , ' GR A N G L P R E S ; YR - 2 0 0 1 6 0 0 ; X R ' , I 4 , 1X , I 3 , ' ; £ ' ) F O R M A T ( I X , ' GR V O L P R E S ; YR - 2 0 0 1 6 0 0 ; X R 5 1 1 5 ; i ' ) FORMAT ( l X , ' T I ''Cylinder pressure vs C r a n k A n g l e ' ';(,') FORMAT ( l X , ' T I ' ' C y l i n d e r p r e s s u r e vs Volume'';i') FORMAT*IX,'DA ' ' ' , F 6 . l , ' rpm'';&') FORMAT ( I X , ' X T I T ' ' C r a n k Angle ( d e g ) '';(>') FORMAT* I X , ' X T I T ' ' V o l u m e ( c u . i n . )'';&') FORMAT*ix,'YTIT ' ' P r e s s u r e p s i '';&') 1  FORMAT*IX,'YG;XG') END  157  APPENDIX  D - COMPUTER  PROGRAM  FOR  DATA  PROCESSING  158  Listing 1 2  3 4 5 6  7 8 9 10 1 1 12  13 14 15 16 1 7 18 19 20 21  22 23 24 25 26 27 28 29 30  C C C C C  C  c  c c c c c  31  32 33 34 35  36 37  c  38 39  40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58  6, 1984 f o r C C i d = AFPH  of APP.PROG 1 a t 22:58:59 on APR  c  T h i s program p r o c e s s e s  data  from d i e s e l  engine  EXTERNAL WTQIO EXTERNAL GETADR EXTERNAL ASNLUN INTEGER INTEGER REAL  LISTC200), IDATC200), IPARM(6), I STAT(2) YES, NO, ANS, IACTIV(2) LOAD  YES = 1 NO = 0 SCALE = 32768.0 calibration  constants  f o r gas flow  C1GAS = 2 . 2 2 C2GAS = -0.0194 CALL 1  PERFRM(VOLDSL,VOLGAS,VOLAIR,SPEED,LOAD,QINPPW,BM; POWER,THRMEF,VOLEFF,PERDSL,RAF,RAD,RAG,0)  WRITE(5,248) READ(5,150) VLOAD LOAD = 5.0 * VLOAD WRITE(5,249) READ(5,150) SPEED WRITE(5,247) READ(5,150) DPQAIR VOLAIR = 2.173 + 0.221 * DPQAIR WRITE(5,245) READ(5,150) DPQGAS c o n v e r t p a s c a l t o i n water VOLGAS = DPQGAS / 248.8 VOLGAS = CI GAS * VOLGAS + C2GAS * VOLGAS * VOLGAS WRITE(5,246) READ(5,150) VOLDSL VOLDSL = VOLDSL * 60.0 CALL PERFRM(VOLDSL,VOLGAS,VOLAIR,SPEED,LOAD,QINPPW,BMEP 1 POWER,THRMEF,VOLEFF,PERDSL,RAF,RAD,RAG,1) WRITE(5,250) WRITE(5,251) SPEED, LOAD, VOLAIR, VOLDSL WRITE(5,254) WRITE(5,255) QINPPW, POWER, BMEP, THRMEF, VOLEFF WRITE(5,256) WRITE(5,257) VOLGAS, PERDSL WRITE(5,258) WRITE(5,259) RAF, RAD, RAG save data i n a f i l e ? WRITE(5,224) READ(5,120) ANS IF (ANS .EQ. NO) GO TO 70 IF (L .EQ. 1) CALL ASSIGN(2, 'OUT.DAT') WRITE(2,250) WRITE(2,251) SPEED, LOAD, VOLAIR, VOLDSL  159  Listing 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 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  of APP.PROG 1 a t 22:58: 59 on APR WRITE(2,252) WRITE(2,253) WRITE(2,254) WRITE(2,255) WRITE(2,256) WRITE(2,257) WRITE(2,258) WRITE(2,259)  6,  1984 f o r C C i d = AFPH  DPTURB, DPCOMP, T1TURB, T2TURB, T1COMP, QINPPW, POWER, BMEP, VOLGAS,  THRMEF,  T2COMP  VOLEFF  PERDSL  RAF, RAD,  RAG  C 70  500  CONTINUE WRITE(5,226) READ(5,120) ANS IF (ANS .EQ. NO) CONTINUE  GO TO 999  C C 999  CONTINUE STOP  100 101 1 02 103 110 120 150  FORMAT(1X,F16.5) FORMAT(1X, I 2) FORMAT(IX, 12) FORMAT(05) FORMAT(A5) FORMAT(II) FORMAT(F12.4)  C  C C 224 225 226 245 246 247 248 249 250 251 253 254 255 256 257 258 259  FORMAT(IX,' ???? E n t e r 1 or 0 t o save d a t a ! ' , $ ) FORMAT(1X,I 5,2X,E14.6) FORMAT(//,'???? To r e r u n e n t e r 1-or 0',$) FORMAT(IX,' >> > E n t e r Gas Flow i n P a s c a l :',$) FORMAT(IX,' >> > E n t e r D i e s e l Flow i n l i t r e / m i n : ' , $ ) FORMAT(IX,' >> > E n t e r A i r Flow i n P a s c a l : ' , $ ) FORMAT(1X,' >> > E n t e r Load i n V o l t a g e : ' , $ ) FORMAT(IX,' >> > E n t e r E n g i n e Speed i n rpm:',?) FORMAT(1X,' Speed (rpm) Load ( l b ) A i r Flow (ft3/min) ', 1 ' D i e s e l Flow ( l t r / h r ) ' ) FORMAT(3X,F7.2,7X,F7.3,7X,F10.3,5X,F10.4) FORMAT(1X,6(F8.2,2X)) FORMAT(5X,'Heat cons Power out BMEP Therm e f f V o l e f f ', 1 5X,'(BTU/hr-hp) (hp) (psi) (%) (%) FORMAT(1X,F15.2,2X,F8.3,2X,F8.3,2X,F8.4,2X,F8.4) FORMAT(10X,'Gas Flow d i e s e l input p r o p o r t i o n (heat)',/, 1 10X,'(ft3/min) ( p e r c e n t t o t a l h e a t ) ') FORMAT(1 OX,F12.3,5X,F8.2,' %') FORMAT(10X,' LAMDA ( t o t ) LAMDA ( d s l ) LAMDA ( g a s ) ' ) FORMAT(1 OX, 3F16.2) END  C C C SUBROUTINE 1 C C C  PERFRM(VOLDSL,VOLGAS,VOLAIR,SPEED,LOAD,QINPPW, BMEP,POWER,THRMEF,VOLEFF,PERDSL,RAF,RAD,RAG,INDEX)  computes p e r f o r m a n c e REAL  characteristics  LOAD,LHVDSL,LHVGAS  160  ;ting of  1 17 1 IB 1 19 1 20 121 1 22  A P P . PROG 1 a t  IF C C C  (INDEX  .NE. 0)  initialize  6,  1984 f o r C C i d = A F P H  C C C  conv.  const  GO TO 10 values  = 1.669  V1SCAG DENDSL DENGAS DENAIR STCDSL HHVDSL STCGAS LHVDSL HHVGAS LHVGAS DSPLMT ARMLEN  131  = = = = =  0.8697 * 6 2 . 2 7 0.044386 0.07541 15.0 1058288.4 •= 16.7 = 1002560.0 = 1024.7 = 926.0 = 425.04 = 17.5 / 12.0  factors  F3PLTR HPPFPM BTUPHP PI  = 0.03531 = 1 . 0 / 33000. = 2 5 4 4 . 4 3 3 / 1.01387  / 0.986315  = 3.1415  C RETURN C  c c c  10  CONTINUE process  data  TQDYNO • LOAD * ARMLEN = TQDYNO * S P E E D * 2.0 * PI * HPPFPM POWER VSWEPT = DSPLMT * S P E E D / 2.0 BMEP = (POWER / HPPFPM * 12.0) / VSWEPT DSLFLW = VOLDSL * F3PLTR GASFLW = VOLGAS * V 1 S C A G = DENAIR * V O L A I R FMAIR = DENDSL * DSLFLW / 6 0 . 0 FMDSL = DENGAS * GASFLW FMGAS RAD = FMAIR / ( S T C D S L * F M D S L ) RAG = 0.0 IF (FMGAS .GT. 0.0) RAG = FMAIR / ( S T C G A S * FMGAS) RAF = FMAIR / ( S T C D S L * FMDSL + STCGAS * FMGAS) = V O L A I R / (VSWEPT / 12.0 / 12.0 / 12.0) * 100. 0 VOLEFF = LHVDSL*DSLFLW / (LHVDSL*DSLFLW+LHVGAS*GASFLW* 60 PERDSL PERDSL •= P E R D S L * 1 0 0 . 0  151  152 153 154  155 156 157 158  159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174  o n APR  C  123 124 125 126 127 128 129 1 30 132 133 1 34 135 136 137 138 1 39 140 141 142 143 144 145 146 147 148 149 1 50  22:58:59  G C C  b r a n c hi o u t n o - l o a d  ie.  idling  IF (ABS(LOAD) .LT. 0.00001) G O T O 11 QINPPW = ( L H V D S L * D S L F L W + LHVGAS*GASFLW* 6 0 . 0 ) / POWER THRMEF = BTUPHP / QINPPW * 1 0 0 . 0 RETURN C  c  1 1  CONTINUE QINPPW  = 0.0  161  Listing 175 176 177 178  of  APP.PROG 1 C  at  THEMEF RETURN END  22:58:59 = 0.0  o n APR  6,  1984 f o r  C C i d = AFPH  162  APPENDIX  E - COMPUTER  PROGRAM  FOR  APPARENT  ENERGY  RELEASE  163  Listing 1 2 3 4 5 6 7 8 9 10 1 1 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page C C C C  c c c c c c c c c c c c c c c  . Rate of Heat R e l e a s e A n a l y s i s  Program  w r i t t e n by : Seaho Song Dec / 1983  T h i s program r e a d s i n t h e c y l i n d e r p r e s s u r e data t o compute t h e r a t e o f heat r e l e a s e f o r e v e r y C A .  Cmmmnmmmmmmmmmmmnmmmnunmmmmmm m Cm Cm Main Routine m m Cm CiTunmmmmmmmrnmmmnimnunmmmmmmmmmmmmmnuninmrnrnmmmmmmmmrnmmnirnmmminrnmrn C C IMPLICIT REAL*8(A-H,0-Z) REAL*8 CYLVOL(180) REAL* 8 GAS ( 1 0 ) , GASNEWOO), P(180) REAL*8 HEATRT(180),ANGLE(180), GASNE0(10),DH01(10), REAL*8 F ( 2 ) , D F D X ( 2 , 2 ) , X ( 2 ) , D X ( 2 ) , F E P ( 2 ) , X E P ( 2 ) , 1 WORKAR(2,2) REAL*8 NTOT, SAVGAS(180,10) INTEGER I PERM(4) COMMON / GEOM / ARM, ROD, BORE, STROKE, VCLEAR COMMON / EXPMT/ SPEED, BMEP COMMON / PROP 1/ DENAIR, DENDSL, DENNG, WTDSL, WTNG, 1 WTAIR COMMON /THDYPR/ H0F(10), R0, WT(10), NGAS  c c c c c  c c c c c c c c  specify cylinder into metric. CONVF1 ARM ROD BORE STROKE VCLEAR To To To To  = 0.0254 =3.0 * = 9.595 * =4.75 * =6.0 * = 6.444 *  geometry  i n inches,  convert  CONVF1 CONVF1 CONVF1 CONVF1 CONVF1**3  smoothen p r e s s u r e d a t a SET use heat t r a n s f e r model SET consider d i s s o c i a t i o n SET o b t a i n output a p p r o p r i a t e f o r p l o t t i n g SET  Setting  then  I SOOT = 1 IHTRSF = 1 IDSSOC = 1 IPLOT  =  1  ISMOOT = 0; IHTRSF = 0; IDSSOC'= 0 w i l l  1  164  Listing 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 B6 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 1 04 1 05 1 06 107 108 109 110 1 1 1 112 1 13 1 14 115 116  of DIG.HEAT.N a t 20:48:34 on MAY C C  assume unsmoothed, a d i a b a t i c ISMOOT IHTRSF IDSSOC I PLOT  c  volume a t e v e r y  CALL GEOMTR(CYLVOL,  CA.  ANGLE)  a s s i g n c o e f f i c i e n t s f o r thermodynamic p r o p e r t i e s of v a r i o u s g a s e s . CALL READPR  c c c c c  read i n c y l i n d e r p r e s s u r e d a t a , i n j e c t e d d i e s e l amount, CH4 amount, and i n j e c t i o n & i g n i t i o n characteristics. CALL DATAIN(GAS,P,DSLAMT,INJBEG,INJEND,IGNBEG)  c c c  w r i t e out t h e mode of o p e r a t i o n and bmep i n kPa BMEPKP = BMEP * 6.8 95D0 IF (GAS(2) .LT. 0.1D-12) 1 WRITE(6,210) SPEED, BMEPKP IF (GAS(2) .GE. 0.1D-12) 2 WRITE(6,211) SPEED, BMEPKP  c c c  smooth t h e P d a t a IF  c  c c  1 1 1 1  compute c y l i n d e r  c c c c  c c c c c c c c c  = = = =  w i t h no d i s s o c i a t i o n .  EPSIL = 0.1E-1  c c c  c  28, 1984 f o r CCid=AFPH Page  (ISMOOT .NE. 1)  GO TO 10  CALL SMOOTP(P, ANGLE, IGNBEG, IPOK) IF (IPOK .EQ. 0) WRITE(6,914) IF (IPOK .EQ. 0) STOP 10  CONTINUE set  up f o r i n i t i a l  stage  FRREM keeps t r a c k of f r a c t i o n of f u e l FRBURN .. ..  remaining. burnt.  The  step  FRREM FRBURN QCACCM PI . V1 Tl  subscript = = = = = =  1 r e f e r s t o the p r e v i o u s 2 .. present  1.0 0.0 0.0 P(1) CYLVOL(1) P1 * VI / R0  .TOTMAS - t o t a l mass o f gases p r e s e n t  2  165  Listing 1 17 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 1 34 135 136 137 138 139 140 141 1 42 143 144 145 146 147 148 1 49 150 151 152 153 1 54 1 55 156 157 158 159 160 161 162 163 164 165 166 167  168  169 170 171 172 173 174  of DIG.HEAT.N a t 20:48:34 NTOT  C  c c c c  - total  on MAY 28, 1984 f o r CCid=AFPH Page number  of Kmoles of gases p r e s e n t  GASM-10) - # of Kmoles of each gas p r e s e n t GASNEW(I-IO) - used t o update GAS(I-IO)  29 C C C C  TOTMAS = 0.D0 NTOT = 0.D0 DO 29 J=1,NGAS GASNEW(J) = GAS(J) TOTMAS = TOTMAS + GAS(J) * WT(J) NTOT = NTOT + GAS(J) CONTINUE DH0TOT - E n t h a l p y a t T1 minus the E n t h a l p y a t 25 f o r t h e t o t a l gas  31  CALL DH0FN(T1,DH01) DH0TOT = 0.0 DO 31 1=1,NGAS DH0TOT = DH0TOT + GASNEW(I) * DH01(I) CONTINUE U2 = DH0TOT - NTOT * R0 * T1  C C  w r i t e headings f o r the output  c  WRITE(6,200)  c  c  c a l c u l a t i o n of r a t e of heat r e l e a s e out f o r each C A . d e g r e e .  c  c  DO 50 ITH=2,180 P2 = P(ITH) V2 = CYLVOL(ITH)  c c c c  update t h e number injected. 1  c  732 750 C  c c. c  25  C  i s carried  of Kmoles of d i e s e l  IF  (ITH .EQ. INJBEG) GAS(1) = GAS(1) + DSLAMT IF (ITH .NE. INJBEG) GOTO 750  TOTMAS = 0.D0 NTOT = 0.D0 DO 732 J=1,NGAS TOTMAS = TOTMAS + GAS(J)*WT(J) NTOT = NTOT + GAS(J) CONTINUE CONTINUE IF (ITH .GE. INJBEG) GO TO 55 no c o m b u s t i o n . processes compression CONTINUE FRAC = 0.0 RN = NTOT * R0 T2 = P2 * V2 / RN  stroke.  166  Listing 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 1 93 1 94 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 21 1 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232  of DIG.HEAT.N C C  C  28, 1984 f o r CCid=AFPH Page  compute r a t e of heat 1  C C C C  a t 20:48:34 on MAY  transfer,  internal  CALL UPROD(P1,P2,T1,T2,V1,V2,GAS,GASNEW,DHO1,FRAC, DHO,NTOT,TOTMAS,U2RES,QC,QHT,0,1HTRSF) GO TO 58 combustion i s t a k i n g p l a c e , p r o c e s s e s combustion and e x p a n s i o n  c55  c c c  c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c c  energy.  stroke.  CONTINUE a s s i g n i n i t i a l guess v a l u e s f o r f r a c t i o n of f u e l b u r n t and t h e gas m i x t u r e t e m p e r a t u r e . IF (FRAC .LT.0.1D-20) FRAC X(1) = FRAC X(2) = P2 * V2 / R0 / NTOT  0.1D-6  u s e i n g m o d i f i e d Newton's method, t h e f o l l o w i n g two a r e c a l c u l a t e d i t e r a t i v e l y : FRAC f r a c t i o n of f u e l b u r n t T2 gas m i x t u r e t e m p e r a t u r e the are  following solved P  system  of two n o m l i n e a r e q a t i o n s  - (nRT/V) 2  U  2 - U + work - Qhtr 2 11 2 1 2  for X  FRAC T2  DO 650 L650=1,50 g i v e n X, compute F CALL GETF(X;F,GAS,T1,P1,P2,V1,V2,NTOT, GASNEW,QHT,QC,TOTMAS,DH 01,DH 0,1HTRSF,IDS SOC) if IF  solution  i s found, terminate the i t e r a t i o n .  ((DABS(F(1)).LT.1.0).AND.(DABS(F(2)).LT.0.1E-4)) GO TO 59 formulate the J a c o b i a n matrix of F a s :  dF/dX  dF / dX 1 1  dF / dX 1 2  dF / dX 2 1  dF / dX 2 2  167  Listing 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250, 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 263 284 285 286 287 288 289 290  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  - 5  C  652 1  653 651 C C C C C  DO 651 LJ=1,2 DO 652 LI=1,2 XEP(LI) = X ( L I ) CONTINUE X E P ( L J ) = X E P ( L J ) + EPSIL CALL GETF(XEP,FEP,GAS,T1,P1,P2,V1,V2,NTOT, GASNEW,QHT,QC,TOTMAS,DH01,DH0,IHTRSF,IDSSOC) DO 653 LI=1,2 DFDX(LI,LJ) = ( F E P ( L I ) - F ( L I ) ) / E P S I L CONTINUE CONTINUE the  iteration X i+1  c c c c c c c  scheme i s as f o l l o w s :  = X + DX i  DX i s o b t a i n e d by s o l v i n g (dFdX) i F(1) F(2)  c c c c  DX = -F i  = -F( 1 ) = -F(2)  the r o u t i n e SLE i a a UBC L i b r a r y s u b r o u t i n e which s o l v e s a system of l i n e a r e q u a t i o n s . 1  c 654 650 66 C C C  c c c  DO 654 LI=1,2 X(LI) = X ( L I ) + DX(LI) CONTINUE CONTINUE CONTINUE iteration  failed,  terminate the execution.  WRITE(6,913) L650, X ( 1 ) , X ( 2 ) GO TO 850 solution 59 58  C C C C  CALL SLE(2,2,DFDX,1,2,F,DX,I PERM,2,WORKAR, DET,JEXP)  found  CONTINUE FRAC = X ( 1 ) T2 = X(2) CONTINUE compute t h e a c c u m u l a t e d h e a t r e l e a s e , a c c u m u l a t e d f r a c t i o n of f u e l b u r n t . QCACCM IANGLE FRBURN FRREM  = QCACCM + QC = ITH - 90 = FRBURN + FRAC * FRREM = 1 . 0 - FRBURN  168  Listing  of DIG.HEAT.K  291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315  C C C  317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348  C C C C  316  a t 20:48:34 on MAY  28, 1984 f o r CCid=AFPH Page  w r i t e out the s o l u t i o n 1  C C C  f o r the c u r r e n t  6  CA.  WRITE(6,201) IANGLE, P2, T2, QHT, QC, QCACCM, FRAC, FRBURN, V2 shift  index f o r next C A .  computation.  T1 P1 V1 DO 71  C C C  C  w r i t e out the s o l u t i o n  851  C C C C C C C C C  C  = T2 = P2 = V2 71 1=1,NGAS DH01(I) = DHO(I) CONTINUE IF (ITH .LT. 80) GO TO 851 IF (ITH .GT. 170) GO TO 851 for plotting  purpose.  IF (IPLOT .NE. 1) GO TO 851 WRITE(1,205) ANGLE(ITH), P2 WRITE(2,205) ANGLE(ITH), T2 WR1TE(3,205) ANGLE(ITH), QCACCM WRITE(4,205) ANGLE(ITH), QC CONTINUE save the i n s t a n t a n e o u s gas m i x t u r e c o m p o s i t i o n t o w r i t e out a t the end of the r a t e of heat r e l e a s e output.  61  IF (ITH .LT. ( I N J B E G - 1 ) ) DO 61 J=1,NGAS GAS(J) = GASNEW(J) SAVGAS(ITH,J) = GAS(J) CONTINUE  GO TO 50  t h i s i s t h e end of t h e p r o c e s s f o r one C.A.. C A . i s i n c r e m e n t e d end the p r o c e s s proceeds t o the next C A . . 50 850  CONTINUE CONTINUE end of a l l the p r o c e s s e s e . w r i t e out the gas m i x t u r e c o m p o s i t i o n f o r each C A . from the C A . j u s t p r i o r t o the d i e s e l i n j e c t i o n .  WRITE(6,202) INJBM1 = INJBEG - 1 DO 72 ITH=INJBM1,180 IANGLE = ITH - 90 WRITE(6,203) IANGLE, (SAVGAS(ITH,J), J=1,NGAS) 72 CONTINUE STOP 200 FORMAT('CA P kPa T deg K, Q htr.(kJ), Q r' 1 'elease , Q accum Frac F r a c cum Vol') 201 FORMAT ( I X , 1 5 , 1 O E M . 5 ) 202 FORMAT( IGas Comp(Kmol) D s l CH4 N2 02 1  169  Listing 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390  391  392 393 394 395 396 397 398 399 400 401 402 403 404 405 406  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  7  1 ' C02 H20 H2 OH CO 2 NO ' ) 203 FORMAT(1X,I 3,7X,10E10.4) 205 FORMAT(1X,2E14.6) FORMATCl S-D O p e r a t i o n Speed = ',F6.1,' rpm, ', 210 1 ' bmep = ',F5.1,' kPa ') FORMATCl D-F O p e r a t i o n Speed = ',F6.1,' rpm, ', 211 1 ' bmep = *,F5.1,' kPa ' ) 913 FORMATC- NO Conv i n fr&T L, f r , T = ',I5,2E14.5) 914 FORMATC- F a i l e d t o Smooth P data ') END C Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c SUBROUTINE READPR s c Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c T h i s r o u t i n e a s s i g n s v a l u s e , f o r v a r i o u s gases, s c d e n s i t y , m o l e c u l a r w e i g h t , e n t h a l p y of f o r m a t i o n , s c number of d i f f e r e n t k i n d of gases c o n s i d e r e d , s c i d e a l gas c o n s t a n t . s c s c Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c c c c  c c c c c c c c c c  IMPLICIT REAL*8(A-H,0-2) COMMON /PROP 1/ DENAIR,DENDSL,DENNG,WTDSL,WTNG,WTAIR COMMON /THDYPR/ H0F(10),RO,WT(10),NGAS density DENAIR = 0.337600E-01 DENDSL = 0.848900E+00 DENNG = 0.1B5760E-01 molecular WTDSL WTNG WTAIR  weight o f i n t a k e gases  = 0.170000E+03 = 0.160000E+02 = 0.137280E+03  number o f d i f f e r e n t k i n d o f gases c o n s i d e r e d , and the i d e a l gas c o n s t a n t . NGAS R0  = 10 = 0.831425E+01  enthalpy H0F(1) H0F(2) H0F(3) H0F(4) H0F(5) H0F(6) H0F(7) H0F(8)  = = = = = = = =  of formation a t standard c o n d i t i o n .  -.290871E+06 -.748730E+05 0.000000E+00 0.000000E+00 -.393522E+06 -.241827E+06 0.000000E+00 0.394630E+05  170  Listing 407 408 409 410 41 1 412  413 414 41 5 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464  of DIG.HEAT.N a t 20:48:34 on MAY  28, 1984 f o r CCid=AFPH Page  8  H0FC9) = -.110529E+06 H0F(10)= 0.905920E+05 C C C  molecular WT( 1) WT(2) WT(3) WT(4) WT(5) WT(6) WT(7) WT(8) WT(9) WT(10)  C C  weight  0. 170000E+03 0.160400E+02 0.280130E+02 0.319990E+02 0.440100E+02 0.180150E+02 0.201600E+01 0.170070E+02 0.280100E+02 0.460000E+02  RETURN END  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss C s SUBROUTINE GEOMTR(CYLVOL, ANGLE) C s Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss C s C T h i s r o u t i n e a s s i g n s v a l u s e f o r the engine geometry s C and computes c y l i n d e r volume a t each C A . s C s Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c  IMPLICIT REAL*8(A-H,0-Z) COMMON / GEOM / ARM, ROD, BORE, STROKE, VCLEAR REAL*B C Y L V O L O 8 0 ) , ANGLE(180)  c c c c c  Computes  in XAREA ARMSQ RODSQ RADPDG compute  100 C C  V, ANGLE  f o r Theta=-90,89 (Crank  Angle)  c u . meter  3.14* BORE * BORE / 4.0 ARM * ARM ROD * ROD 3.14 / 180.0 cylinder  volume  ITH1 = -89 ITH2 = 90 DO 100 ITH=ITH1,ITH2 TH = DFLOAT(ITH) RD = TH * RADPDG X = ROD+ARM*(1.O-DCOS(RD))-DSQRT(RODSQ-ARMSQ*DSIN(RD)**2) CYLVOL(ITH+90) = XAREA * X + VCLEAR ANGLE(ITH+90) = TH CONTINUE  171  Listing 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 51 1 512 513 514 515 516 517 518 519 520 521 522  of DIG.HEAT.N  a t 20:4B:34 on MAY 28, 1984 f o r CCid=AFPH Page  _ 9  RETURN END C Cssssssssssssssssssssssssssssssssssssssss5sssssssssssssssssss  c  S  SUBROUTINE DATAIN(GAS, P,  c  DSLAMT,INJBEG,INJEND,IGNBEG) s  CSSSSSSSSS5SSSSSSSSSSSSSSSSSSSSSSSSSSSSS5SSSSSSSSSSSSSSSSS5SS  c c c c c c c  S  T h i s r o u t i n e r e a d s i n t h e d a t a f o r i n j e c t i o n and i g n i t i o n c h a r a c t e r i s t i c s , c y l i n d e r p r e s s u r e , engine speed, BMEP, flow r a t e s of a i r , g a s , d i e s e l . The flow r a t e s a r e c o n v e r t e d t o number of Kmoles per c y c l e r .  CSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS5SS5  c  IMPLICIT REAL*8(A-H,0-Z)  c  c c c c c c c c c c c c c c" c c c  c  c c c  c c  10  COMMON / EXPMT / SPEED, BMEP COMMON / PROP 1 / DENAIR, DENDSL, DENNG, WTDSL, 1 VJTNG, WTAIR REAL*8 GAS(10), P(180) Reads i n from  Log U n i t 10  SPEED BMEP  -  engine speed i n rpm load i n p s i  QAIR QDSL QNG  -  a i r flow i n f t 3 / m i n d i e s e l flow i n l t r / h r n a t gas flow i n f t 3 / m i n  INJBEG INJEND IGNBEG  -  b e g i n n i n g of d i e s l i n j i n deg C A . end of d i e s e l i n j i n deg C A . b e g i n n i n g of i g n i t i o n i n deg C A .  P(1-180) READ(10,100) READ(10,101) READ(10,102)  cylinder  in psi  SPEED, BMEP QAIR, QDSL, QNG INJBEG,INJEND,IGNBEG  JA = 1 DO 10 L=1,36 JB = JA + 4 READ(10,103) ( P ( J ) , J=JA,JB) JA = L * 5 + 1 CONTINUE c o n v e r t p r e s s u r e data  20  pressure  from  p s i t o kPa  DO 20 J=1,180 P ( J ) = P ( J ) * 6.895 CONTINUE compute # o f moles p e r c y c l e :  s s s s s s  172  Listing 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page C C  GAS(2) (3) (4)  c c c  c c c  30  n a t gas N2 02  DO 30 L=1,20 GAS(L) = 0.0 CONTINUE making sure of # o f c y l i n d e r = 4 GAS(2) AIRMOL GAS(3) GAS(4)  c c c  = = = =  QNG * DENNG / SPEED * 2.0 / WTNG / 4.0 QAIR * DENAIR / SPEED * 2.0 / WTAIR 3.76 * AIRMOL / 4.0 AIRMOL /4.0  compute amount of d i e s e l  injected  i n kmoles  DSLAMT = QDSL / 60.0 * DENDSL / SPEED * 2.0 / WTDSL / 4.1  c c 100 101 102 103  c  -  10  RETURN FORMAT(1X, F6.1, 1X, F5.1) FORMAT(IX, F5.1, 1X, F5.2, 1X, FORMAT(IX,3(13,IX)) FORMAT(IX, 5(F6.1,1X)) END  F5.2)  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c SUBROUTINE UPROD(P1,P2,T1,T2,V1,V2,GAS,GASNEW,DHO1,FRAC, 1 DHO,NTOT,TOTMAS,U2RES,QC,QHT,ICOMB,IHTRSF) s c Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c T h i s r o u t i n e c h e c k s out whether t h e f i r s t law i s met. s c The d e v i a n c e from t h e f i r s t law i s d e s i g n a t e d by U2RES.S c s c Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c  c c c c c c c  IMPLICIT REAL*8(A-H,0-Z) REAL*8 GAS(10),GASNEW(10),R1(10),DH01(10),DH0(10),NTOT COMMON /THDYPR/ H 0 F ( 1 0 ) , R0, WT(10), NGAS WORK  = 0.5D0 * (PI + P2) * <V2 - V1)  CALL DH0FN(T2,DH0) IF  (ICOMB .EQ. 0)  GOTO 5  compute t h e heat r e l e a s e due t o combustion the c u r r e n t C A . i n t e r v a l . QC = O.ODO DO 20 1=1,NGAS QC = QC + (GASNEW(I) - G A S ( I ) ) 1 * (H0F(I) + DH0(I) - R0 * T2)  during  173  Listing 581 582 583 584 585 586 587 588 589 590  of DIG.HEAT.N a t 20:48:34 on MAY 20  59B  599 600 601 602 603 604 605 606 607 608 609 610 61 1 612 613 614  615  616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638  11  CONTINUE  C QC = -QC C 5  CONTINUE IF (I COMB .EQ. 0)  QC = 0.0  C C  591  592 593 594 595 596 597  28, 1984 f o r CCid=AFPH Page  30 C C C C C  C  c c  DU = 0.D0 R0DT = R0 * (T2 - T l ) DO 30 1=1,NGAS DU = DU + GAS(I) * (DHO(I) - DHO1(1) - R0DT) CONTINUE comput heat t r a s f e r . i f IHTRSF i s s e t t o 0, a d i a b a t i c assumed. QHT IF QHT  10  processe i s  = 0.D0 (IHTRSF .NE. 1) GO TO 10 = QHTRSF(T2,V2,GASNEW,TOTMAS)  CONTINUE U2RES = DU + WORK - QC - QHT RETURN END  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c  c  s SUBROUTINE  STCHPD(GAS,FRAC,GASNEW)  s  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c c c c c  T h i s r o u t i n e computes the number of Kmoles of s t o i c h i o m e t r i c combustion p r o d u c t , and y i e l d the updated c o m p o s i t i o n of t h e gas m i x t u r e i n t h e cylinder.  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c c c c c c  IMPLICIT REAL*8(A-H,0-2) COMMON /THDYPR/ H O F ( l O ) , R0, WT(10), NGAS REAL*8 GAS(10), GASNEW(lO), N, M M - number o f moles o f d i e s e l N .. CH4  burnt at current C A .  M = GAS(1) * FRAC N = GAS(2) * FRAC GASNEW(1) GASNEW(2) GASNEW(3) GASNEW(4) GASNEW(5) GASNEW(6)  = = = = = =  GAS(1) GAS(2) GAS(3) GAS(4) GAS(5) GAS(6)  - M - N - 18.5*M - 2.0*N + 12.0*M + N + 13.0*M + 2.0*N  s s s s s s  174  Listing 639 640 641 642 64 3 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 67 3 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690  691  692 693 694 695 696  of DIG.HEAT.N a t  20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  DO 10 C  10 1=7,NGAS GASNEW(I) = GAS(I) CONTINUE RETURN END  C Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssss C s SUBROUTINE SMOOTP(P, ANGLE, IGNBEG, IPOK) C s Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssss C s C T h i s r o u t i n e uses C u b i c - S p l i n e - L e a s t - S q u a r e s - F i t s C t o smooth the c y l i n d e r p r e s s u r e d a t a . s C The r a t e of p r e s s u r e r i s e i s n u m e r i c a l l y computed s C from the UNSMOOTHED d a t a , and t h i s i s used i n s C weight t o c o n t r o l the degree of l o c a l smoothness. s C The w e i g h t i n g i s based on s c a t t e r n e s s t h e of s l o p o f s C of the p r e s s u r e d a t a . s C s Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssss C IMPLICIT REAL*8(A-H,0-Z) C REAL* 8 P ( 1 8 0 ) , DPDTHO80), T O L ( l B O ) , ANGLE ( 1 80) REAL*8 P D l ( l B O ) , PD2(180) REAL*8 W(2000) C C compute dp/dTheta by f i t t i n g a q u a d r a t i c through C 3 points C DO 5 J=2,179 DPDTH(J) = (P(J+1) - P ( J - l ) ) / 2.DO 5 CONTINUE DPDTH(1) = (4.D0*P(2) -3.D0*P(1) - P ( 3 ) ) /2.D0 DPDTHC180) = (3.D0*P(180)-4.D0*P(179)+P(17B))/2.DO C C TOL0 c o n t r o l s the l o c a l smoothness. C SVAL .. the g l o b a l C TOL0 = 1.0 SVAL = 1000.0 IPOK = 1 DO 10 1=4,177 JS = I - 3 JF = I + 2 AV = 0.0 DO 11 J=JS,JF AV = AV + DPDTH(J) 11 CONTINUE AV = AV / 10.0 C C SD i s a measure of s c a t t e r n e s s i n t h e s l o p of C of t h e p r e s s u r e d a t a . T h i s i s computed by C c o n s i d e r i n g 4 adjacent p o i n t s . C SD = 0.0  12  175  Listing 697 698 699 700 701 702 703 704 705 706 707 708 709 710 71 1 712 713 714 715 716 717 718  of DIG.HEAT.N a t 20:48:34 on MAY  13  DO 12 C C C C  12 J=JS,JF SD = SD + DABS(DPDTH(J) - AV)**2 CONTINUE T O L ( I ) = TOL0 * DABS(SD / AV / AV) The the  10 20 30 C C C C C  c c c c  degree of smoothness i s l e s s f o r c e d f o r p o i n t s b e f o r the s t a r t of i g n i t i o n .  IF (DABS(DFLOATCI-IGNBEG)).LT.5.0) T O L ( I ) = T O L ( I ) / 1 0 CONTINUE DO 20 1=1,3 TOL(I) = TOL(4) CONTINUE DO 30 1=178,180 TOL(I) = TOL(177) CONTINUE The r o u t i n e s DSPLFT and DSPLN a r e UBC L i b r a r y s u b r o u t i n e s , which p e r f o r m s Least-Squares-Fit w i t h C u b i c - S p l i n e as b a s i s f u n c t i o n s . CALL DSPLFT (ANGLE, P, TOL, SVAL, 180,W,5,613) CALL DSPLN (ANGLE, P,PD1 ,PD2, 180,5.61 3) RETURN  719  720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754  28, 1984 f o r CCid=AFPH Page  613  c  CONTINUE The  f i t has  failed  IPOK = 0 RETURN END  CSSSSSSSS5SSSS5SS5SSSSSSSSSSSSSSSSSSSSSSS5SSSSSSSSSSSSSSS5  c c  s SUBROUTINE VISCST(T,GAS,VISC)  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c c  computes mean v i s c o u s i t y  of gas m i x t u r e s .  Csssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c  c c  c  IMPLICIT  REAL*8(A-H,0-Z)  REAL*8 GAS(10) COMMON /THDYPR/ TM = VISC VISC VISC VISC VISC VISC  T**0.645 = = VISC + = VISC + = VISC + = VISC + = VISC +  H0F(10),R0,WT(10),NGAS  GASO) GAS(2) GASO) GAS(4) GAS(5) GAS(6)  * * * * * *  WT(1) WT(2) WT(3) WT(4) WT(5) WT(6)  * * * * * *  1.33 3.35 4.57 5.09 3.71 3.26  TOTW = GAS(1)*WT(1)+GAS(2)*WT(2)+GAS(3)*WT(3) 1 + GAS(4)*WT(4)+GAS(5)*WT(5)+GAS(6)*WT(6)  s s s s  176  Listing 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCicUAFPH Page C  14  VISC = VISC / TOTW * 10.**(-7) * TM RETURN END  C C C Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff f c DOUBLE PRECISION FUNCTION QHTRSF(T2,V2,GASNEW,TOTMAS) f c Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff f c T h i s r o u t i n e computes t h e heat t r a n s f e r a t c u r r e n t f c Annand's model i s used. f c f c Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff  c  IMPLICIT REAL*8(A-H,0-Z)  c  COMMON COMMON REAL*8  c c c c  T h i s r o u t i n e employees Annand's model t o compute t h e r a t e of heat t r a n s f e r .  30  c c c c c c c  c c c c c c  / GEOM / ARM,ROD,BORE,STROKE,VCLEAR /EXPMT / SPEED, BMEP GASNEW(10)  A = 0.47D0 C = 1.6D-12 CP = CP0VAL(T2,GASNEW) / TOTMAS CONTINUE PISVEL = SPEED * STROKE / 30.0 CALL VISCST(T2,GASNEW,VISC) DENTOT = TOTMAS / V2 RENUM = DENTOT * PISVEL * BORE / VISC REKD = CP * VISC / 0.7 / BORE * RENUM**(0.7) The w a l l t e m p e r a t u r e i s assumed t o be p r o p o r t i o n a l to the a p p l i e d l o a d . TW  = 0.484 * BMEP + 540.0  The s u f a c e a r e o f t h e c y l i n d e r SURFA = (V2 - VCLEAR) * 4.DO / BORE + 0.0304D0 QCONVC = A * SURFA * REKD* (T2 - TW) QRAD = (1.6E-12)*(10.76)*C*SURFA*(T2**4-TW**4) QHTRSF = -(QCONVC + QRAD) *  (60./SPEED/360.)  RETURN END  Cssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss S C  177  Listing 813 814 B15 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870  o f DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  15  SUBROUTINE DSSOCN(P,T,GAS1,GAS2,NTOT) C  S  CS5SSSSSSSSSSSSSSSSSS5SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS5  c c c c c c c c c c c c c c c c c c c c  T h i s r o u t i n e computes the e q u i l i b r i u m d i s s o c i a t i o n p r o d u c t s . The t h e o r e t i c a l d e t a i l s i n c l u d i n g the n u m e r i c a l methods a r e d e s c r i b e d i n the e x t e r n a l documentation. The r e a c t i o n s c o n s i d e r e d 1. 2.  CO 2  <==>  HO 2  <==>  HO 2  <==>  are: CO  + 1/2 0 2  1/2 H  +  OH  2  s s s s s s s s s s s s s 5  3. 4.  1/2 N  2  H  + 1/2 O 2  + 1 / 2 0 <==> 2  2  NO  s s s s s  5 CSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS5  c  IMPLICIT  c  COMMON REAL*8 REAL*8 REAL*8 INTEGER  c  c  c c c c c c  c  5  REAL*8(A~H,O-Z)  /THDYPR/ HOF(10),R0,WT(10),NGAS GAS1(10), G A S 2 O 0 ) , NTOT K ( 4 ) , F ( 5 ) , FEP(5),KPOP(4), DX(5), X ( 5 ) , XEP(5) WORKDB(5,5), DXDBL(5), FDBL(5),DFDXDB(5,5),DETDBL I PERM(10)  SUMN = 0.0 DO 5 1=1,NGAS GAS2(I) = GAS 1(I) SUMN = SUMN + GAS 1(I) CONTINUE IF (GAS1(5) .GE. 0.1E-20) NTOT = SUMN RETURN  500  GO TO 500  CONTINUE compute the e q u i l i b r i u m c o n s t a n t s temperature. K(1) K(2) K(3) K(4) POP KP0P(1) KP0P(2) KP0P(3)  = = = =  f o r the g i v e n  DEXP(DLOG(T)**(-7.4721)*(-0.65549E+8)+10.53) DEXP(DLOG(T)**(-7.0457)*(-0.30372E+8)+l0.159) DEXP(DLOG(T)**(-6.8674)*(-0.18879E+8)+8.7095) DEXP(DLOG(T)**(-7.3355)*(-0.16593E+8)+1.80127)  = = = =  101.325DO/P K(1) * K(1)*P0P K(2) * K(2)*P0P K(3) * K(3)*P0P  178  Listing 871 872 873 674 B75 876 677 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 91 1 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928  of DIG.HEAT.N at.20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page K P O P U ) = K(4) * K(4) C C C  c c  if  the r e a c t i o n s a r e i n s i g n i f i c a n t ,  then  skip.  10  RMK =0.0 DO 10 1=1,4 IF (DABS(KP0P(I ) ) .GT. RMK) RMK = DABSCKPOPdi CONTINUE IF (RMK .GT. 0.1E-5) GO TO 20 NTOT = SUMN RETURN  20  CONTINUE  C C C  initial  40 C  c c c c c  X(1) = K(1)*DSQRT(P0P/SUMN/GAS1(4))*GAS1(5) X(1) = X(1) - GAS 1(9) / SUMN X(3) = K(3)*DSQRT(P0P/SUMN/GAS1(4))*GAS1(6) X(3) = X(3) - GAS 1(7) / SUMN X(2) = K(2)*DSQRT(P0P/SUMN)*GAS1(6) X(2) = X(2)/DSQRT(DABS(GAS1(7)+X(3)*SUMN)) X(2) = X(2) - GAS1(8)/SUMN X(4) = K(4)*DSQRT(GAS1(3)*GAS1(4))/SUMN X(4) = X(4) - GAS 1 (10)/SUMN X(5) = SUMN CONTINUE S o l v e f o r X u s i n g m o d i f i e d Newton's method. The method i s p r e c i s e l y t h e same a s t h a t i n the main r o u t i n e , and t h e n o t a i o n s a r e a l s o n e a r l y t h e same. TOL = DABS ( K P O P U ) ) * 0.1 D-4 DO 50 L=1,100 . CALL EVALF(X,GAS2,KP0P,SUMN,F)  c c c c  I t i s s u f f i c i e n t t o check o n l y t h e F ( 4 ) , s i n c e i t i s t h e most s l o w l y c o n v e r g i n g term. IF  c  (DABS(F(4)) .LT. TOL)  GOTO 300  53 51  DO 51 LJ=1,5 EPSIL = DSQRT(0.1D-12+0.1D0*DABS(X(LJ))) DO 52 LI=1,5 XEP(LI) = X(LI) CONTINUE X E P ( L J ) = X E P ( L J ) + EPSIL CALL EVALF(XEP,GAS2,KP0P,SUMN,FEP) DO 53 LI=1,5 DFDXDB(LI,LJ) = ( F E P ( L I ) - F ( L I ) ) / EPSIL CONTINUE CONTINUE  55  DO 55 LI=1,5 FDBL(LI) = CONTINUE  52  c  guess  .  -F(LI)  179  Listing 929 930 931 932 933 934 935 936 937 938 939 940 94 1 942 94 3 944 94 5 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 97 3 974 975 976 977 978 979 980 981 982 983 984 985 986  of DIG.HEAT.K a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page C C C C C C  A g a i n , SLE i s a UBC L i b r a r y s u b r o u t i n e , which s o l v e s a system of l i n e a r e q u a t i o n s . In s o l v i n g t h e systems of e q u a t i o n s , t h e r o u t i n e r e t a i n s t h e decomposed m a t r i x . CALL 1  SLE(5,5,DFDXDB,1,5,FDBL,DXDBL,I PERM,5,WORKDB, DETDBL,JEXB)  C 54  C C C C C  Here, once a J a c o b i a n m a t r i x i s formed f o r F, i t i s used f o r 3-4 i t e r a t i o n s , t h u s r e d u c i n g the c o s t .  71 C C C C C C  73 C C C  DO 54 LI=1,5 X ( L I ) = X ( L I ) + DXDBL(LI) CONTINUE NTOT = X ( 5 ) A = X(1) * NTOT B = X(2) * NTOT C = X(3) * NTOT D = X ( 4 ) * NTOT GAS2(3) = DABS(GAS1(3) - 0.5*D) GAS2(4) = DABS(GAS1(4) + 0.5MA+C-D)) GAS2(5) = DABS(GAS1(5) - A) GAS2(6) = DABS(GAS1(6) - B - C) GAS2(7) = DABS(GAS1(7) + 0.5*B + C) GAS2(8) = DABS(GAS1(8) + B) GAS2(9) = DABS(GAS1(9) + A) G A S 2 O 0 ) = DABS (GAS 1(10) + D)  DO 70 J70=1,3 CALL EVALF(X,GAS2,KP0P,SUMN,F) DO 71 LI=1,5 FDBL(LI) = - F ( L I ) CONTINUE The r o u t i n e DBS i s a l s o a UBC L i b r a r y r o u t i n e . The r o u t i n e uses t h e decomposed m a t r i x by t h e r o u t i n e SLE t o v e r y e c o n o m i c a l l y compute new s o l u t i o n w i t h newly g i v e n FDBL CALL DBS(5,1,5,FDBL,DXDBL,I PERM,5,WORKDB) DO 73 LI=1,5 X ( L I ) = X ( L I ) + DXDBL(LI) CONTINUE update t h e c o m p o s i t i o n NTOT = X ( 5 ) A = X ( 1 ) * NTOT B = X ( 2 ) * NTOT C = X ( 3 ) * NTOT D = X ( 4 ) * NTOT GAS2(3) = DABS(GAS1(3) GAS2(4) = DABS(GAS 1(4) GAS2(5) = DABS(GAS1(5) GAS2(6) = DABS(GAS1(6) GAS2(7) = DABS(GAS1(7)  of t h e gas m i x t u r e .  + +  0.5*D) 0.5*(A+C-D)) A) B - C) 0.5*B + C)  17  180  Listing 987 988 989 990 991 992 993 994 995 996 997 998 999 1 000 1001 1002 1003 1 004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1 023 1024 1025 1026 1027 1 028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1 040 1041 1042 1043 1044  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  70 50 C C  + B) + A) + D)  I t e r a t i o n has f a i l e d . The e x e c u t i o n w i t h a p r o p e r e r r o r message.  c c  c c c  GAS2(8) = DABS(GAS1(8) GAS2(9) = DABS(GAS1(9) G A S 2 O 0 ) = DABS (GAS 1(10) CONTINUE CONTINUE  18  will  terminate  WRITE(6,213) STOP mission completed. 300 213  c c  Exit.  CONTINUE RETURN FORMATC- xXxXxXxXxX F a i l END  t o Converge i n Dssocn  xXxXxX  Csssssssssssssssssssssssssssssssssssssssssssssssssssss s c SUBROUTINE EVALF(X,N,KP0P,SUMN,F) S c CSSSSSSSSSSSSSSSSSSSSSS5SSSSSSSSSSSSSSSSSSSSSSSS5SSSSS  c c c c c c  T h i s r o u t i n e c h e c k s t h e a p p r o p r i a t e n e s s of the g i v e n p o s s i b l e s o l u t i o n f o r t h e equilibrium dissociation. The d e v i a t i o n i s d e s i g n a t e d by t h e v e c t o r F.  s s s s. s s  CSSSSSSSSS5SSSSSSSSSSSSSSSSSSSSSSSSSSS5SSSSSSSSSSSSSSS  c c c c  c  c c c  IMPLICIT  REAL*8(A-H,0-Z)  REAL*8 X ( 5 ) , N ( 1 0 ) , KP0P(4), F ( 5 ) , NTOT NTOT = X(5) TERM1 = N(4)/NTOT+0.5*(X(1)+X(3)-X(4)) TERM2 = (N(7)/NTOT + 0.5*X(2) + X ( 3 ) ) TERM3 = (N(3)/NTOT-0.5*X(4))*(N(4)/NTOT 1 +0.5*(X(1)+X(3)-X(4))) F(1) 1 F(2) 1 F(3) 1 F(4) 1 F(5)-  = = = = =  RETURN END  (N(9)/NTOT+X(1))**2*TERM1/(N(5)/NTOT-X(1))**2 - KP0P(1) TERM2*(N(B)/NTOT+X(2))**2/(N(6)/NTOT-X(2)-X(3)) - KP0P(2) TERM2**2 * TERM1 / ( N ( 6 ) / N T O T - X ( 2 ) - X ( 3 ) ) * * 2 - KP0P(3) (N(10)/NTOT+X(4))**2/TERM3 -KP0P(4) (SUMN-NTOT)-0.5D0*(X(1)+X(2)+X(3))*NTOT  181  Listing 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1 064 1065 1 066 1067 1068 1069 1 070 1071 1072 1073 1 074 1075 1076 1 077 1078 1 079 1 080 1 081 1082 1083 1 084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1 100 1101 1 102  of DIG.HEAT.N a t 20:48:34 on MAY 28, 1984 f o r CCid=AFPH Page  19  C Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c SUBROUTINE GETF(X,F,GAS,T1,P1,P2,V1,V2,NTOT, 1 GASNEW,QHT,QC,TOTMAS,DHO1,DHO,IHTRSF,IDSSOC) s c Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c T h i s r o u t i n e c h e c k s t h e a p p r o p r i a t e n e s s of t h e g i v e n s c p o s s i b l e s o l u t i o n s f o r t h e requrements f o r t h e f i r s t s c law and t h e i d e a l gas law. T h i s r o u t i n e i s used i n s c the main r o u t i n e f o r computing t h e f r a c t i o n of f u e l s c b u r n t and T2. s c s c Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c  IMPLICIT REAL*8(A-H,0-Z)  c  REAL*8 X(2),F(2),GAS(10),GASNEW(10),DH0(10) ,DH01 (10) REAL*8 NTOT,GASNE0(20) COMMON /THDYPR/ H0F(10),R0,WT(10),NGAS  c  FRAC = X ( 1 ) T2 = X(2)  c  50 51  c c c  IF (IDSSOC .EQ. 0) GO TO 50 CALL STCHPD(GAS,FRAC,GASNE0) CALL DSSOCN(P2,T2,GASNE0,GASNEW,NTOT) GO TO 51 CONTINUE CALL STCHPD(GAS,FRAC,GASNEW) CONTINUE CALL UPROD(P1,P2,T1,T2,V1,V2,GAS.GASNEW,DHO1,FRAC, 1 DHO,NTOT,TOTMAS,U2RES,QC,QHT,1,IHTRSF) F(1) F(2)  = P2 - NTOT * R0 * T2 / V2 = U2RES  RETURN END  c Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffff f c c  DOUBLE PRECISION FUNCTION CP0VAL(T,GAS)  f Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffff f c T h i s r o u t i n e computes t h e mean v a l u e of t h e s p e c i f i c f c heat Cp. f c f c Cffffffffffffffffffffffffffffffffffffffffffffffffffffffffff  c  c c  IMPLICIT REAL*8(A-H,0-Z) COMMON /THDYPR/ H 0 F ( 1 0 ) , R0, WT(10),NGAS REAL*8 GAS(10), C P 0 ( 1 0 ) , NTOT  182  Listing 103 104 105 106 107 108 109 110 1 1 1 1 12 1 13 1 14 115 1 16 1 17  of DIG.HEAT.N a t 20:48:34 on MAY  138  1 39 140 141 142 143 144 145 146 147 148 149 1 50 151 152 153 154 1 155 1156 1 157 1 158 1 159 1 160  20  C TH = T / 100.0 TH2 = TH * TH TQ = TH**(0.25) TQ2 = TQ * TQ TQ2 = TQ * TQ * TQ TQ6 = TQ3*TQ3 C CP0C1) = CP0(2) = CP0(3) = CP0(4) = CP0(5) = CP0(6) = CP0(7) = CP0(8) = CP0(9) = CP0(10)=  118 1 19  120 121 122 123 124 125 126 1 27 1 28 1 29 1 30 131 132 133 134 135 136 137  28, 1984 f o r CCid=AFPH Page  104.18 + 465.5 * (T / 1000.0) -672.87 + 439.74*TQ - 24.875*TQ3 + 323.88/TQ2 39.06-512.79/TQ6+1072.7/TH2-820.4/(TH**3) 37.432 + 0.020102*TQ6-178.57/TQ6+236.88/TH2 -3.7357+30.529*TQ2-4.1034*TH+0.024198*TH2 143.05-183.54*TQ+82.751*TQ2-3.6989*TH 56.505-702.74/TQ3+1165.O/TH-560.7/TQ6 81.546-59.35*TQ+17.329*TQ3-4.266*TH 69.145-0.70463*TQ3-200.77/TQ2+l76.76/TQ3 46.045+216.1/TQ2-363.66/TQ3+232.55/TH2  C C  C C  20  CPOVAL = 0.0 DO 20 1=1,NGAS DO 20 I=2,NGAS CPOVAL = CPOVAL + C P 0 ( I ) * GAS(I) CONTINUE RETURN END  C C C Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c  c  SUBROUTINE  DH0FN(T,DH0)  5  s Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss s c T h i s r o u t i n e computes t h e change i n e n t h a l p y s c between t h e g i v e n t e m p e r a t u r e and 298 deg K. s c s c The u n i t f o r DH0O-10) i s kJ/Kmol-K s c s c Csssssssssssssssssssssssssssssssssssssssssssssssssssssssssss  c c c  c  IMPLICIT REAL*8(A-H,0-Z) REAL*8 T2 T3 TQ2 TQ TQ3 TQ5 TQ6 TQ7  = = = = = = = =  DH0(10) T*T T*T*T DSQRT(T) DSQRT(TQ2) TQ * TQ2 T * TQ T * TQ2 T * TQ3  DH0(1) = 104.18*T+0.23276*T2-51714.3  183  L i s t i n g of DIG.HEAT.N a t 20:48:34 on MAY 161 162 163 1 64 165 166 167 1 68 169 170 171 172 173 174 175 176 1 77 178 179 180 181 182 183 1 84 185 186 187 188 189 1 90 191  28, 1984 f o r CCid=AFPH Page  C DHO(2) =  -672.B7*T+111.25*TQ5-0.449495*TQ7+6477.6*TQ2 -39442.6  DH0(3) =  39.06*T+0.102558D7/TQ2-0.10727D8/T+0.4102D9/T2 -39672.7  C C DH0(4) = DHO(5) = DHO(6) • DH0(7) = DHO(8) DHO(9) =  C C  DHO(10)= RETURN END  37.432*T+0.0080408D-3*T2*TQ2+0.35714D6/TQ2 -0.23688D7/T - 23906.6 -3.7357*T+2.0353*TQ6-2.0517D-2*T2 +0.008066D-4*T3 - 7556.3 143.05*T-46.432*TQ5+5.51667*TQ6-0.0184 94 5*T2 - 11876.4 56.505*T-0.8889D5*TQ+0.1165D6*DLOG(T) + 0.11214D7/TQ2 - 376187.0 81.546*T-15.0144*T5+0.313137*TQ7-0.0213 3*T2 -10509.4 69.145*T-0.0127328*TQ7-0.40154D4*TQ2 +0.223586D5*TQ - 43912.9 59.283*T-0.11397 3*T6-0.141226D4*TQ2 - 0.149778D6/TQ2 + 15975.8  21  

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