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UBC Theses and Dissertations

Evaluation of a partially stratified charge insert in a natural gas engine Logan, Jean-Michel 2011

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EVALUATION OF A PARTIALLY STRATIFIED-CHARGE INSERT IN A NATURAL-GAS ENGINE by Jean-Michel Logan Diploma Tech., Camosun College, Victoria, British Columbia, Canada, 2002 B.Sc., University of Victoria, Victoria, British Columbia, Canada, 2005 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF  THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES (Mechanical Engineering) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) April, 2011 © Jean-Michel Logan, 2011 Abstract Partially Stratified Charge (PSC) technology is one of many ideas that can be used to ex- tend the lean limit of operation.  It is accomplished by introducing a small quantity of pure natural gas, usually on the order of 5% of weight or less of the overall fuel quantity, in the local area of the spark plug electrode, whereas the rest of the mixture in the com- bustion cylinder is homogenous and very lean.  This creates opportunity for more stable ignition, which in turn increases the likelihood of flame propagation throughout the com- bustion cylinder.  The PSC insert technology herein requires neither engine nor spark plug modification, as the insert itself provides the passageway to move natural gas from the injector to the spark plug electrode. 2 different PSC inserts and corresponding spark plug sizes were tested, one accepting an 8mm spark plug with different injection configurations possible, and one accepting a 14mm spark plug with only injections aimed directly at the spark plug gap possible. It was demonstrated that PSC insert technology can successfully extend the lean limit of operation with both spark plug sizes.  It was also demonstrated that different injection patterns and electrode offsets can be more beneficial than others.  Using the herein defined homogenous lean limit cut off range of 5% coefficient of variation, an 8mm spark plug using an injection pattern creating more "swirl" in the local area and offset slightly from the electrode is able to decrease the created nitrous oxide emissions by up to 71% at 2500rpm, and an extended lean limit of lambda = 1.67 at 2000rpm versus the homogenous limit of 1.47.  This same PSC geometry also increased brake mean effective pressures by up to 9.7%. The PSC insert using a 14mm spark plug achieved an extended lean limit of lambda = 1.71 at 2000rpm versus the homogenous limit of 1.56, brake specific fuel consumption improvements of 4%, and brake mean effective pressure improvements of up to 4%.  At the extended relative air-fuel ratio, nitrous oxide values were higher than, but still very close to, the homogenous lean limit values. ii Table of Contents Abstract ii.............................................................................................................. Table of Contents iii............................................................................................. List of Tables v..................................................................................................... List of Figures vii.................................................................................................. List of Symbols xii................................................................................................ List of Abbreviations xiii..................................................................................... Acknowledgements xiv.........................................................................................  1. INTRODUCTION 1................................................................................. 1.1. Background 1.......................................................................................... 1.1.1. CNG as a Fuel 1................................................................................... 1.2. Lean Burning Engines 3.......................................................................... 1.3. Local Charge Stratification 6.................................................................. 1.4. Research Objectives 7.............................................................................  2. EXPERIMENT 8...................................................................................... 2.1. Ricardo Hydra Engine 8.......................................................................... 2.2. PSC Insert System 10.............................................................................. 2.2.1. PSC Natural Gas Supply 10................................................................. 2.2.2. Injection Solenoids 11.......................................................................... 2.2.3. Back-Flow Prevention - LEE Micro Check Valve 11.......................... 2.2.4. Original PSC Insert Design 12............................................................. 2.2.5. New PSC Insert Design 15................................................................... 2.2.6. Spark Plugs 18...................................................................................... 2.3. DAQ and Instrumentation Interface 19................................................... 2.4. Uncertainties 20....................................................................................... 2.5. Repeatability 21.......................................................................................  3. RESULTS AND DISCUSSION 26......................................................... 3.1. Injection Timing 26................................................................................. 3.2. Ideal Tube Length Timing Tests 29........................................................ 3.3. Baseline Test Results 31......................................................................... 3.3.1. Coefficient of Variation 34.................................................................. 3.3.2. BSFC, Thermal Efficiency, and BMEP 35.......................................... 3.3.3. Emissions 37........................................................................................ 3.4. Original PSC Low Flow Results 40........................................................ 3.4.1. Lean Limit Extension 40...................................................................... 3.4.2. BSFC, Thermal Efficiency, and BMEP 41.......................................... 3.4.3. Emissions 45........................................................................................ 3.5. Original PSC High Flow Results 48....................................................... iii 3.5.1. Lean Limit Extension 48...................................................................... 3.5.2. BSFC, Thermal Efficiency, and BMEP 49.......................................... 3.5.3. Emissions 51........................................................................................ 3.6. New PSC Low Flow Results 54.............................................................. 3.6.1. Lean Limit Extension 54...................................................................... 3.6.2. BSFC, Thermal Efficiency, and BMEP 56.......................................... 3.6.3. Emissions 61........................................................................................ 3.7. New PSC High Flow Results 66............................................................. 3.7.1. Lean Limit Extension 66...................................................................... 3.7.2. BSFC, Thermal Efficiency, and BMEP 68.......................................... 3.7.3. Emissions 71........................................................................................ 3.8. New PSC - AFC Injector Tests 74.......................................................... 3.8.1. Lean Limit Extension 74...................................................................... 3.8.2. BSFC, Thermal Efficiency, and BMEP 75.......................................... 3.8.3. Emissions 77........................................................................................ 3.9. Natural Gas Dead Volume 79.................................................................  4. CONCLUSIONS 81................................................................................. 4.1. Conclusions 81........................................................................................ 4.2. Recommendations for Future Work 83................................................... References 85....................................................................................................... Appendices 87...................................................................................................... Appendix A: Drawings 87................................................................................ Appendix B: Additional Graphs of Data Results 95........................................ Appendix C: Engine Operating Procedures 121.............................................. iv List of Tables Table 1: Natural Gas Composition, % Mol 2..................................................... Table 2: Ricardo Hydra Geometry 8.................................................................. Table 3: Distance of Original PSC Spark Gap to Fire Deck 14......................... Table 4: Original PSC Setup Terminologies 15................................................. Table 5: Distance of New PSC Spark Gap to Fire Deck 17............................... Table 6: New PSC Prototype Setup Terminologies 18...................................... Table 7: Spark Plug Dimensions 19................................................................... Table 8: Ricardo Hydra Main Instrumentation Specifications 20...................... Table 9: Repeatability Analysis for RAFR = 1.34 22........................................ Table 10: Repeatability Analysis for RAFR = 1.53 22........................................ Table 11: Lean Limit Extension, Original PSC, Low Flow 41............................ Table 12: BMEP Improvements, Original PSC, Low Flow 44............................ Table 13: % Change in NOx Emissions, Original PSC, Low Flow 45................ Table 14: % Increase in tHC and CH4 Emissions, Original PSC, Low Flow 47. Table 15: Lean Limit Extension, Original PSC, High Flow 49........................... Table 16: BMEP Improvements, Original PSC, High Flow 50........................... Table 17: % Change in NOx Emissions, Original PSC, High Flow 52............... Table 18: % Increase in tHC and CH4 Emissions, Original PSC, High Flow53 Table 19: Lean Limit Extension, New PSC, Low Flow 55.................................. Table 20: New PSC, Low Flow - BSFC and Thermal Efficiency Improvements .........................................................................................................59 Table 21: New PSC, Low Flow - BMEP Improvements 60................................ Table 22: New PSC NOx Differences, Low Flow 62.......................................... Table 23: % Change in tHC and CH4 Emissions, New PSC-A, Low Flow 64... Table 24: % Change in tHC and CH4 Emissions, New PSC-B, Low Flow 64... Table 25: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-A, Low Flow 64........................................................................... Table 26: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-B, Low Flow 65........................................................................... Table 27: Lean Limit Extension, New PSC, Low Flow 67.................................. Table 28: New PSC, High Flow - BSFC and Thermal Efficiency Improvements .........................................................................................................69 Table 29: New PSC, High Flow - BMEP Improvements 70................................ Table 30: New PSC NOx Differences, High Flow 72.......................................... Table 31: % Change in tHC and CH4 Emissions, New PSC-A, High Flow 73... v Table 32: % Change in tHC and CH4 Emissions, New PSC-B, High Flow 73... Table 33: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-A, High Flow 73.......................................................................... Table 34: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-B, High Flow 74.......................................................................... Table 35: Lean Limit Extension, New PSC, AFC Solenoid 75........................... Table 36: BSFC Improvements, New PSC, AFC Solenoid 76............................ Table 37: BMEP Improvements, New PSC, AFC Solenoid 76........................... Table 38: NOx Differences, New PSC, AFC Solenoid 77................................... Table 39: tHC and CH4 Differences, New PSC, AFC Solenoid 79..................... Table 40: Dead Volume Calculation 80............................................................... Table 41: Dead Volume CH4 Contribution Calculation (g/kw-hr) 80................. vi List of Figures Figure 1: Ratio of Specific Heats of Unburned Gasoline, Air, Burned Gas Mixtures as Function of Temperature, Equivalence Ratio, and Burned Gas Fraction 3...................................................................................... Figure 2: Variation of HC, CO and NO Concentration in the Exhaust of a Conventional Spark-Ignition Engine with Fuel/Air Equivalence Ratio. Source: Heywood 5.............................................................................. Figure 3: PSC Spark Plug 6................................................................................. Figure 4: Ricardo Hydra Test Engine and PSC Insert Schematic 9.................... Figure 5: PSC Supply Pressure Diagram 10........................................................ Figure 6: LEE Micro Check Valve Body and Connectors 11............................. Figure 7: LEE Micro Check Valve Body Cross-Section 12................................ Figure 8: LEE Micro Valve 12............................................................................ Figure 9: Original PSC Insert with Spark Plug 13.............................................. Figure 10: Original PSC Insert Injection Pattern 13.............................................. Figure 11: Original PSC Insert Design with Spacer Dimension 14...................... Figure 12: Original PSC Spark Gap to Fire Deck Distance X 14.......................... Figure 13: New PSC Insert with Spark Plug 15.................................................... Figure 14: Injection Patterns A (radial) and B (swirl) 16...................................... Figure 15: Injection Pattern C (penetrative) 17..................................................... Figure 16: New PSC Insert Design with Spacer Dimension 17............................ Figure 17: New PSC Spark Gap to Fire Deck Distance X 18............................... Figure 18: Spark Plug Dimensions 19................................................................... Figure 19: Baseline Repeatability - Coefficient of Variability 23......................... Figure 20: Baseline Variability - BSFC 23............................................................ Figure 21: Baseline Variability - BMEP 24........................................................... Figure 22: Baseline Variability - Nitrous Oxide Generation 24............................ Figure 23: Baseline Variability - Total Hydrocarbon Generation 25.................... Figure 24: Baseline Variability - Methane Generation 25..................................... Figure 25: Schlieren SOI and EOI Examples 27................................................... Figure 26: Effect of Pulse Width on Start of Injection 27..................................... Figure 27: Omega Solenoid, Effect of Pulse Width on Fuel Flow Rate, 1500rpm .........................................................................................................28 Figure 28: Omega Solenoid, Fuel Flowrate vs Injection Duration, 1500rpm 28.. Figure 29: Ideal Length PSC Insert 29.................................................................. Figure 30: Ideal PSC Tube Length Injection Duration Analysis 30...................... vii Figure 31: Ideal Tube Length Mass Flowrate Analysis 30.................................... Figure 32: Effect of Original PSC Geometry on Flame Propagation 32............... Figure 33: Effect of NEW PSC Geometry on Flame Propagation 32................... Figure 34: Baseline Coefficient of Variation of IMEP, 2000rpm 34.................... Figure 35: Baseline Coefficient of Variation of IMEP, 2500rpm 34.................... Figure 36: Baseline BSFC, 2000rpm 35................................................................ Figure 37: Baseline BSFC, 2500rpm 35................................................................ Figure 38: Baseline BMEP, 2000rpm 36............................................................... Figure 39: Baseline BMEP, 2500rpm 36............................................................... Figure 40: Baseline Total Hydrocarbon Emissions, 2000rpm 37.......................... Figure 41: Baseline Total Hydrocarbon Emissions, 2500rpm 37.......................... Figure 42: Baseline Methane Emissions, 2000rpm 38.......................................... Figure 43: Baseline Methane Emissions, 2500rpm 38.......................................... Figure 44: Baseline Nitrous Oxide Emissions, 2000rpm 39................................. Figure 45: Baseline Nitrous Oxide Emissions, 2500rpm 39................................. Figure 46: Original PSC, Coefficient of Variation, Low Flow, 2000rpm 40........ Figure 47: Original PSC, BSFC, Low Flow, 2000rpm 41..................................... Figure 48: Original PSC, Thermal Efficiency, Low Flow, 2000rpm 43............... Figure 49: Original PSC, BMEP, Low Flow, 2000rpm 44................................... Figure 50: Original PSC, Nitrous Oxide Emissions, Low Flow, 2000rpm 45...... Figure 51: Original PSC, tHC Emissions, Low Flow, 2000rpm 46...................... Figure 52: Original PSC, Methane Emissions, Low Flow, 2000rpm 46............... Figure 53: Original PSC, Coefficient of Variation, High Flow, 2000rpm 48....... Figure 54: Original PSC, BSFC, High Flow, 2000rpm 49.................................... Figure 55: Original PSC, BMEP, High Flow, 2000rpm 50................................... Figure 56: Original PSC, Nitrous Oxide, High Flow, 2000rpm 51....................... Figure 57: Original PSC, Nitrous Oxide, High Flow, 2500rpm 51....................... Figure 58: Original PSC, Total Hydrocarbons, High Flow, 1500rpm 52.............. Figure 59: Original PSC, Methane, High Flow, 1500rpm 53................................ Figure 60: New PSC-A, Coefficient of Variation, Low Flow, 1500rpm 54.......... Figure 61: New PSC-B, Coefficient of Variation, Low Flow, 1500rpm 54.......... Figure 62: New PSC-A, BSFC, Low Flow, 1500rpm 56...................................... Figure 63: New PSC-B, BSFC, Low Flow, 1500rpm 56...................................... Figure 64: New PSC-A, BSFC, Low Flow, 2000rpm 57...................................... Figure 65: New PSC-B, BSFC, Low Flow, 2000rpm 57...................................... Figure 66: New PSC-A, BSFC, Low Flow, 2500rpm 58...................................... viii Figure 67: New PSC-A, BMEP, Low Flow, 2000rpm 59..................................... Figure 68: New PSC-B, BMEP, Low Flow, 2000rpm 60..................................... Figure 69: New PSC-A, Nitrous Oxide Emissions, Low Flow, 2500rpm 61........ Figure 70: New PSC-B, Nitrous Oxide Emissions, Low Flow, 2500rpm 61........ Figure 71: New PSC-A, Total Hydrocarbons, Low Flow, 2500rpm 62................ Figure 72: New PSC-B, Total Hydrocarbons, Low Flow, 2500rpm 63................ Figure 73: New PSC-A, Coefficient of Variation, High Flow, 2000rpm 66......... Figure 74: New PSC-B, Coefficient of Variation, High Flow, 2000rpm 66......... Figure 75: New PSC-A, BSFC, High Flow, 2000rpm 68..................................... Figure 76: New PSC-B, BSFC, High Flow, 2000rpm 68...................................... Figure 77: New PSC-A, BMEP, High Flow, 2000rpm 69.................................... Figure 78: New PSC-B, BMEP, High Flow, 2000rpm 70..................................... Figure 79: New PSC-A, Nitrous Oxide, High Flow, 2000rpm 71........................ Figure 80: New PSC-B, Nitrous Oxide, High Flow, 2000rpm 71......................... Figure 81: New PSC, Coefficient of Variation, AFC Solenoid, 2000rpm 74....... Figure 82: New PSC, BSFC, AFC Solenoid, 2000rpm 75.................................... Figure 83: New PSC, BMEP, AFC Solenoid, 2000rpm 76................................... Figure 84: New PSC, Nitrous Oxide Emissions, AFC Solenoid, 2000rpm 77..... Figure 85: New PSC, tHC Emissions, AFC Solenoid, 2000rpm 78...................... Figure 86: New PSC, Methane Emissions, AFC Solenoid, 2000rpm 78.............. Figure 87: Injection Schematic 79......................................................................... Figure 88: Original PSC, Coefficient of Variation, Low Flow, 2500rpm 95........ Figure 89: Original PSC, BSFC, Low Flow, 2500rpm 95..................................... Figure 90: Original PSC, Thermal Efficiency, Low Flow, 2500rpm 96............... Figure 91: Original PSC, BMEP, Low Flow, 2500rpm 96................................... Figure 92: Original PSC, tHC Emissions, Low Flow, 2500rpm 97...................... Figure 93: Original PSC, Methane Emissions, Low Flow, 2500rpm 97............... Figure 94: Original PSC, Coefficient of Variation, High Flow, 1500rpm 98....... Figure 95: Original PSC, Coefficient of Variation, High Flow, 2500rpm 98....... Figure 96: Original PSC, BSFC, High Flow, 2500rpm 99.................................... Figure 97: Original PSC, BMEP, High Flow, 1500rpm 99................................... Figure 98: Original PSC, BMEP, High Flow, 2500rpm 100................................. Figure 99: Original PSC, Total Hydrocarbons, High Flow, 2000rpm 100............ Figure 100: Original PSC, Total Hydrocarbons, High Flow, 2500rpm 101.......... Figure 101: Original PSC, Methane, High Flow, 2000rpm 101............................ Figure 102: Original PSC, Methane, High Flow, 2500rpm 102............................ ix Figure 103: New PSC-A, Coefficient of Variation, Low FLow, 2000rpm 102.... Figure 104: New PSC-B, Coefficient of Variation, Low Flow, 2000rpm 103...... Figure 105: New PSC-A, Coefficient of Variation, Low Flow, 2500rpm 103...... Figure 106: New PSC-B, Coefficient of Variation, Low Flow, 2500rpm 104...... Figure 107: New PSC-A, BMEP, Low Flow, 1500rpm 104................................. Figure 108: New PSC-A, BMEP, Low Flow, 2500rpm 105................................. Figure 109: New PSC-B, BMEP, Low Flow, 2500rpm 105.................................. Figure 110: New PSC-B, Total Hydrocarbons, Low Flow, 1500rpm 106............ Figure 111: New PSC-B, Total Hydrocarbons, Low Flow, 2000rpm 106............ Figure 112: New PSC-A, Coefficient of Variation, High Flow, 1500rpm 107..... Figure 113: New PSC-B, Coefficient of Variation, High Flow, 1500rpm 107..... Figure 114: New PSC-A, Coefficient of Variation, High Flow, 2500rpm 108..... Figure 115: New PSC-B, Coefficient of Variation, High Flow, 2500rpm 108..... Figure 116: New PSC-A, BSFC, High Flow, 1500rpm 109.................................. Figure 117: New PSC-B, BSFC, High Flow, 1500rpm 109.................................. Figure 118: New PSC-A, BSFC, High Flow, 2500rpm 110.................................. Figure 119: New PSC-B, BSFC, High Flow, 2500rpm 110.................................. Figure 120: New PSC-A, BMEP, High Flow, 1500rpm 111................................. Figure 121: New PSC-B, BMEP, High Flow, 1500rpm 111................................. Figure 122: New PSC-A, BMEP, High Flow, 2500rpm 112................................. Figure 123: New PSC-B, BMEP, High Flow, 2500rpm 112................................. Figure 124: New PSC-A, Nitrous Oxide, High Flow, 1500rpm 113..................... Figure 125: New PSC-B, Nitrous Oxide, High Flow, 1500rpm 113..................... Figure 126: New PSC-A, Nitrous Oxide, High Flow, 2500rpm 114..................... Figure 127: New PSC-B, Nitrous Oxide, High Flow, 2500rpm 114..................... Figure 128: New PSC-A, Total Hydrocarbons, High Flow, 1500rpm 115........... Figure 129: New PSC-B, Total Hydrocarbons, High Flow, 1500rpm 115............ Figure 130: New PSC-A, Total Hydrocarbons, High Flow, 2000rpm 116........... Figure 131: New PSC-B, Total Hydrocarbons, High Flow, 2000rpm 116............ Figure 132: New PSC-A, Total Hydrocarbons, High Flow, 2500rpm 117........... Figure 133: New PSC-B, Total Hydrocarbons, High Flow, 2500rpm 117............ Figure 134: New PSC-A, Methane, High Flow, 1500rpm 118.............................. Figure 135: New PSC-B, Methane, High Flow, 1500rpm 118.............................. Figure 136: New PSC-A, Methane, High Flow, 2000rpm 119.............................. Figure 137: New PSC-B, Methane, High Flow, 2000rpm 119.............................. Figure 138: New PSC-A, Methane Emissions, High Flow, 2500rpm 120............ x Figure 139: New PSC-B, Methane, High Flow, 2500rpm 120.............................. xi List of Symbols λ Relative Air-Fuel Ratio γ Specific Fuel Ratio WR Experimental Uncertainty Wx Individual Uncertainty xii List of Abbreviations ABDC After Bottom Dead Centre ATDC After Top Dead Centre BBDC Before Bottom Dead Centre BMEP Brake Mean Effective Pressure BSFC Brake Specific Fuel Consumption BTDC Before Top Dead Centre CH4 Methane CNG Compressed Natural Gas CO Carbon Monoxide CO2 Carbon Dioxide COV Coefficient of variation GHG Greenhouse Gas LML Lean Misfire Limit LNG Liquid Natural Gas MBT Minimum Advance for Best Torque MFB Mass Fraction Burned NOX Nitrogen Oxides PSC Partially Stratified Charge RAFR Relative Air-Fuel Ratio rpm Revolutions Per Minute tcf Trillion Cubic Feet tHC Total Hydrocarbons UBC University of British Columbia xiii Acknowledgements First and foremost, I would like to thank my friends and family who have been very supportive of my challenging decision to return to school after working in industry, and to keep on going when things seemed bleak - I couldn't have done it without all of you. Liz Willms, thank you for your love and support. I am very grateful to the amazing support staff that has helped me learn about and surpass the challenges I have met.  Roland Genschorek for the great discussions about machining, Erik Wilson for all the times I needed things from the shop, Benny Nimmervoll for getting straight to the point, Markus Fengler for how to approach people and teach students, Glenn Jolly and Sean Buxton for the electronics I knew nothing about, Perry Yabuno for always helping me find the things I need, Bob Parry for the countless times of advice and help in the CERC facility, Sarah Chen for making things run smoothly at CERC, and Yuki Matsumura for helping me with the terrible paperwork that no graduate student knows about.  Above all, thank you all for having the time to laugh. My lab mates who have helped me truly understand a topic I knew nothing about and being there to laugh with through those countless long days.  Edward Chan, Malcolm Shield, James Saunders, Eric Kastanis, Arminta Chicka, Chris Laforet, Amir Aliabadi and Mahdi Salehi - your discussions about food, life, religion, politics, technical matters and different kinds of coffees will be forever cherished. Last but not least, I would like to thank Dr. Robert Evans for the opportunity to complete a degree at the University of British Columbia.  It has been a privilege to learn from and work with so many people, and I wouldn't have had the opportunity without your assistance. xiv Chapter 1: INTRODUCTION 1.1 Background “Humanity is conducting an unintended, uncontrolled, globally pervasive experiment whose ultimate consequences could be second only to global nuclear war.  The Earth’s atmosphere is being changed at an unprecedented rate by pollutants resulting from human activities, inefficient and wasteful fossil fuel use, and the effects of rapid population growth in many regions.  These changes represent a major threat to international security and are already having harmful consequences over many parts of the globe.”(WMO et al. 1988) Another world issue today is that the heavy reliance on fossil fuels has created a pollution heavy automotive industry.  The only solution is to find alternative, clean(er) methods to provide transportation means to the consumer.  This has sparked interest in compressed natural gas (CNG) as an automotive fuel. 1.1.1 CNG as a Fuel Natural gas is a fossil fuel, historically a by-product of oil wells, but now ever-increasing amounts are provided from wells drilled explicitly for natural gas.  Though natural gas composition varies widely from field to field, it is composed mostly of methane and is usually processed to remove gases such as propane, butane, pentane, and other hydrocarbons.  Methane (CH4) itself is a very effective greenhouse gas (GHG), whose ability to trap heat in the atmosphere over 100 years is 23 times greater than that of carbon dioxide.  Over the short term of 20 years, it is 62 times more powerful (Dauncey and Mazza 2001, 7).  The typical American and British Columbian market compositions are provided in Table 1 (Ingersoll 1996, 44), (Westport Innovations 2010). 1 Table 1: Natural Gas Composition, % Mol Component Symbol Typical Ranges inField Marketed US Westport Innovations (Feb 2010) Methane CH4 70-90 94 94.9 Ethane C2H6 0-20 3 2.14 Propane C3H8 0.7 0.53 Butane C4H10 0.5 0.2 Carbon Dioxide CO2 0-8 1.2 0.2 Oxygen O2 0-0.2 trace trace Nitrogen N2 0-5 0.6 0.54 Hydrogen Sulphide H2S 0-5 trace trace Rare Gases A, He, Ne,Xe trace An important characteristic of natural gas is its high octane number, typically ranging from 115 to 130, compared to gasoline, with values typically in the 85-95 range (Heywood 1988, 915).   Higher octane values allow usage in high compression ratio engines, and to increase engine resistance to knock (Attar and Karim 2003, 500), (Malenshek and Olson 2009), (Rahmouni et al. 2004). The octane number is directly related to the auto-ignition of a fuel  (Rahmouni C. et al. 2004).  The lower the fuel octane rating, the lower the pressure necessary to auto-ignite the fuel.  As a flame propagates through the combustion chamber, the unburnt portion ahead of the flame front is compressed, increasing its pressure, temperature, and density characteristics.  The possibility exists that some of this fuel-air mixture may go through some chemical reactions before combustion actually takes place.  These new products may auto-ignite, burning very rapidly, the results of which are high frequency pressure oscillations that create the noise known as knock (Heywood 1988, 453-454). CNG use in the transportation sector has the potential to greatly decrease the high levels of local and atmospheric pollution.  Engines modified to function on CNG provide reductions in carbon monoxide (CO), carbon dioxide (CO2), nitrogen (NOX) and total hydrocarbons (tHC), Benzene, Formaldehyde and Acetaldehyde (Springer, Smith and Dickinson 1994).  Vehicles operating on CNG emit 58% lower nitrogen oxide emissions and 98% less particulate matter than comparable diesel vehicles (Frailey et al. 2000). When compared to gasoline, all emission levels are 5 to 50% lower for natural gas (Evans 2 and Blasczyk 1994, vi).  This can also be observed on engine startup, when CNG emits only 35% more total hydro-carbons (tHC’s) than when warmed up, as opposed to gasoline, which emits up to 160% more.  "Generally, it is found that gaseous fuels show less elevated hydrocarbon emissions at cold-start conditions" (Raine, Zhang and Pflug 1997, 46). 1.2 Lean Burning Engines An even better solution than adjusting pre-existing diesel and gasoline engines is to create an optimized, low emission design solely for natural gas use.  Technology that shows promise when used in combination with natural gas fuelling is the lean burn spark engine (Cho and He 2007, 613).   In a lean burning engine, the power output is varied by varying the relative air-fuel ratio (RAFR) λ, while keeping the throttle constant.  Leaner ratios have higher specific heat ratios (γ), as can be seen by the following Figure 1 from Heywood (Heywood 1988, 134) and the ratio of specific heats from Cheung and Heywood (Cheung and Heywood 1993, 3). Figure 1: Ratio of Specific Heats of Unburned Gasoline, Air, Burned Gas Mixtures as Function of Temperature, Equiv- alence Ratio, and Burned Gas Fraction 3 Equation 1: Specific Heat as a Function of Lambda Equation 2: Definition of Lambda Leaner ratios possibly increase the thermal efficiency of the engine as the pumping losses associated with throttling at part-load use are eliminated.  It is observed that for leaner fuel ratios, CO concentrations decrease, tHC levels decrease to a point when cycle-to- cycle combustion becomes less reliable, then begin to increase again.  Also, the lower burned gas temperatures from lean burning allow for lower NOX emissions.  The effect of leaner fuel ratios on CO, NO, and tHC levels can be seen in Figure 2. Lean burning does have problems that must be addressed.  Leaning the mixture out too far can cause cyclic variations between combustion cycles, as well as increased  tHC levels. Cyclic variations can render a vehicle inoperable when the coefficient of variation(COV) is greater than 10%, which is also described as the lean misfire limit (LML).  4 Figure 2: Variation of HC, CO and NO Concentration in the Exhaust of a Conventional Spark-Ignition Engine with Fuel/Air Equivalence Ratio. Source: Heywood The increased emissions created by lean burning can be reduced by augmenting the turbulence created within the combustion chamber.  Turbulence is helpful as the mixing rates are several times greater than the rates due to molecular diffusion (Heywood 1988, 453-454).  One method used to accomplish this is through the use of the UBC squish jet (Raine, Zhang and Pflug 1997, 46).  When compared to traditional bowl in piston designs, the UBC squish jet combustion chamber demonstrated lower emission levels, as well as thermal efficiency gains of up to 5%  (Evans and Blasczyk 1998). Another method that has shown promise in stabilizing lean combustion is Local Charge Stratification.   This involves injection of a relatively rich fuel mixture near the spark plug to promote the formation of a stable flame kernel to ensure combustion of the surrounding lean mixture. 5 1.3 Local Charge Stratification Green and Zavier demonstrated the possibility of lean limit extension while showing improvements in fuel consumption at lean air-fuel ratios by using local charge stratification.  Their CO values were similar or slightly lower than the homogenous operation, while tHC values increased.  They believed the increase was due to incomplete combustion of quenched fuel in the injection tube and burning the injected fuel at the rich flammability limit (Green and Zavier 1992). Local Charge Stratification was further explored by Reynolds, who designed the PSC sparkplug system shown in Figure 3 to use in the lean combustion process of a natural gas engine (Reynolds 2001). Figure 3: PSC Spark Plug Reynolds injected natural gas through a capillary tube to the spark area.  For tests at full load, and speeds of 2000 and 2500 rpm, improved engine performance was observed when compared to lean air-fuel ratios for homogenous fuelling.  Air-fuel ratios greater than λ = 1.5 point toward improved brake specific fuel consumption (BSFC), up to 7% at λ = 1.65.  Reynolds also saw a 7% gain in brake mean effective pressure (BMEP) at λ = 1.65, as well as an extension of the lean misfire limit (LML) from λ = 1.6 to 1.7. A 7 6 degree decrease in ignition delay and a 4 degree decrease in combustion delay was observed at λ = 1.65.  Time to reach 95% mass fraction burned (MFB) from spark was reduced by 15%.  CO emissions were lower at all RAFR values, reaching a 25% decrease at λ = 1.65.  tHC values were similar both for PSC use and homogenous fuel mixtures up to λ = 1.65. NOX values were higher when using PSC up to λ = 1.65.  The extension of the lean limit past λ = 1.65 meant that lower overall NOX emissions were possible. tHC values, however, increased rapidly past λ = 1.65. 1.4 Research Objectives The research presented in this paper continues the successful work of previous UBC graduate students with the local charge stratification technique in lean burning engines through the use of PSC sparkplug technology in a Ricardo Hydra test engine operating on natural gas. The PSC technology tested herein was altered from a modified sparkplug, such as one used by Reynolds (Reynolds 2001), into a novel PSC insert design created at the Clean Energy Research Centre (CERC) of the University of British Columbia (UBC).  The PSC insert was designed to accept standard 14mm spark plugs and fit into a standard 18mm spark plug thread.  A second PSC insert prototype was designed to accept 3 different injection nozzle configurations and standard 8mm spark plugs. The objective of this thesis is to examine the capability of the PSC inserts to extend the lean misfire limit, decrease NOX emissions, and improve BSFC and BMEP results. It aims to do this as it is easier to fabricate new components that accept standard sparkplugs than modifying existing sparkplugs for use.  It also aims to determine the effect of offsetting the injection location from the spark plug electrode, and to determine which of 3 injection nozzle patterns function the best.  The methods to accomplish this are described in the next section entitled: Experiment. 7 Chapter 2: EXPERIMENT All experiments conducted for this thesis were performed on a Ricardo Hydra engine, serial number 30.  The Ricardo Hydra engine test bed is very flexible, and can be set to operate with a range of fuels and injection methods.  In the case of this thesis, natural gas was injected through a specially designed PSC insert into the combustion chamber, and ignited using a standard 14mm spark plug.  The injected quantity is controlled by changing the driving pulse duration, and adjusting the delivery pressure.  Carbon monoxide, carbon dioxide, nitrogen oxides, and total hydrocarbons were measured using a comprehensive emissions bench.  Experimental results such as cylinder pressures, air fuel ratios, fuel and air flow rate, were acquired using National Instrument digital acquisition (DAQ) systems, and controlled with a Labview interface previously developed for the Ricardo Hydra. 2.1 Ricardo Hydra Engine The Ricardo Hydra engine is a modular construction engine capable of functioning on a variety of fuels, including diesel, gasoline, CNG, and methanol.  The cylinder geometry and the DAQ system  have not changed since modifications performed by Gorby (Gorby 2007).  All of the relevant piston geometry is included in Table 2, a drawing of the piston crown is available in Appendix A, and a schematic of the engine setup is included in Figure 4 . Table 2: Ricardo Hydra Geometry Bore 81.5 mm Stroke 88.9 mm Clearance Volume 54.7 cc Displaced Volume 463.3 cc Compression Ratio 9.47:1 Inlet Valve Diameter 36 mm Inlet Valve Open 12˚ BTDC Inlet Valve Close 56˚ ABDC Exhaust Valve Diameter 33.5 mm Exhaust Valve Open 56˚ BBDC Exhaust Valve Close 12˚ ATDC 8 Figure 4: Ricardo Hydra Test Engine and PSC Insert Schematic 9 2.2 PSC Insert System The PSC system used in these experiments is very similar to that used on separate occasions in the past by Brown (Brown 2003), Reynolds (Reynolds 2001) and Gorby (Gorby 2007).  The main difference being that the original PSC system involved spark- plug modifications, whereas the new PSC insert system presented herein allows the use of standard spark plugs.  Also, an improved PSC gas supply was installed, as well as an improved backflow check valve. 2.2.1 PSC Natural Gas Supply A direct line natural gas (NG) supply was installed during the summer of 2008 to allow for more consistent, longer test periods.  This supply was thoroughly tested by Arminta Chicka, a fellow graduate student, for consistency.   The best option resulting in the least amount of pressure variations, which occur due to the use of an on site compressor to supply the gas, was chosen.  This option is a 2 stage regulator combination, which is a combination well known to smooth out pressure variations (Yaws 2001, 950). The installed NG supply system, shown in Figure 5, works as follows: The first regulator drops the pressure from 4500psi to 1800psi.  The gas then flows to a secondary regulator where the pressure is again dropped to the PSC supply pressure of 150psi. Figure 5: PSC Supply Pressure Diagram 10 2.2.2 Injection Solenoids The main test cases were performed using an Omega SV122 solenoid using a custom in- jection driver box supplying 100V and up to 6A of current. All dead volumes within the solenoid were decreased as much as possible by machining polytetrafluoroethylene (PTFE) parts to suit. It has been remarked upon by Gorby (Gorby 2007) and Reynolds (Reynolds 2001) that this model solenoid offers poor opening and closing times (heretofore referred to as reaction times) and is possibly a source of increased tHC and CH4 emissions. It has been the main challenge of these experiments to solve the prob- lems with solenoid reaction times and decrease the hydrocarbons emitted. An alternate solenoid, the AFC 121 was initially used for testing. Unfortunately, it suf- fered a premature breakdown, very likely due to the injection driver overloading the coils. This breakdown was demonstrated by loss of reliability in opening and closing times. 2.2.3 Back-Flow Prevention - LEE Micro Check Valve It was determined that the pressure created during the combustion process was forcing exhaust emissions back through the PSC insert and the injector. This problem was solved with the incorporation of a LEE Company Micro-Valve, part number CHRA1256501A. A custom stainless steel valve body was manufactured in house.! Flow Direction Valve Body Figure 6: LEE Micro Check Valve Body and Connectors 11 Figure 7: LEE Micro Check Valve Body Cross-Section Figure 8: LEE Micro Valve 2.2.4 Original PSC Insert Design The original PSC insert was designed and commissioned by David Gorby (Gorby 2008). It accepts a standard 14mm spark plug, model ZFR6A-11, and this interaction can be seen in Figure 9. The injection pattern, seen in Figure 10, is radial, and is aimed at the center of the PSC spark plug geometry. A 1mm spacer is also used in testing to determine if a slight offset of the injection to the spark plug electrodes will have any effect on com- bustion. Setups are described as using a 0mm or 1mm spacer, as seen in Figure 11. The 0mm spacer aligns the axis of the injection pattern with the center of the electrode gap. Distances from the center of the spark plug gap to the fire deck are listed in Table 3 and visually represented in Figure 12. A summary of the different spacer setup and injection pattern terminologies used throughout this thesis can be seen in Table 4. 12 Figure 9: Original PSC Insert with Spark Plug Figure 10: Original PSC Insert Injection Pattern 13  Gas Flow Spacer Figure 11: Original PSC Insert Design with Spacer Dimension Table 3: Distance of Original PSC Spark Gap to Fire Deck Brass Spacer Thickness (mm) Center of Spark Gap Distance from Fire Deck (X, mm) 0 2.02 1 2.92 Figure 12: Original PSC Spark Gap to Fire Deck Distance X 14 Table 4: Original PSC Setup Terminologies Terminology Description Original - 0 Original PSC Design, no spacer Original - 1 Original PSC Design, 1mm spacer 2.2.5 New PSC Insert Design The new design accepts a standard 8mm spark plug, model ER9EH. The new PSC insert prototype uses the same gas supply method as the original insert, the main difference is that injection patterns are quickly and easily interchangeable thanks to the use of a removable head. The insert is made of brass, and uses the action of the spark plug tight- ening to create a sandwiched face seal between the main insert body and the removable heads. The 8mm spark plug was necessary, as changeable injection patterns using the original 14mm spark plug would have necessitated modifications to the Ricardo engine head, which was not an option at the time of this work. Figure 13: New PSC Insert with Spark Plug Three injection hole layouts were designed for testing, all with 8 injection holes 15 1. Radial - Pattern A - Similar to the original PSC design, where gas is injected radi- ally directly to the axis.  This can be seen in Figure 14. 2. Swirl - Pattern B - Injection holes were offset by 2mm. This is to create a swirl motion, which may aid in turbulence generation and mixing of the air and fuel. This can be seen in Figure 14. 3. Penetrative - Pattern C - Pairs of opposing injection holes were angled in 15 de- gree increments towards the combustion cylinder. This is to aid the flame front movement by adding fuel as it progresses into the combustion cylinder. This can be seen in Figure 15. Schlieren imagery confirmed the predicted gas flow of these three patterns. Unfortunate- ly, Pattern C was damaged at the beginning of testing, and there is limited data available. A new one was not acquired due to time constraints within the lab. A 1mm and 3mm spacer is again used in testing to determine if there is an effect on combustion. Setups are described as using a 0mm, 1mm, or 3mm spacer, as shown in Figure 16. Ideally, a 1.5mm spacer would align the injection with the center of the spark gap. Distances from the center of the spark plug gap to the fire deck are listed in Table 5 and visually repre- sented in Figure 17. A summary of the different spacer setup and injection pattern termi- nologies used throughout this thesis can be seen in Table 6. Figure 14: Injection Patterns A (Radial) and B (Swirl) 16 Figure 15: Injection Pattern C (Penetrative) Spacer Gas Flow Figure 16: New PSC Insert Design with Spacer Dimension Table 5: Distance of New PSC Spark Gap to Fire Deck Brass Spacer Thickness (mm) Center of Spark Gap Distance from Fire Deck (X, mm) 0 1.35 1 2.25 3 4.05 17 Figure 17: New PSC Spark Gap to Fire Deck Distance X Table 6: New PSC Prototype Setup Terminologies Terminology Description New - 0 New PSC Prototype, no spacer New - 1 New PSC Prototype, 1mm spacer New - 3 New PSC Prototype, 3mm spacer New - A0 New PSC Prototype,  Injection Pattern A (radial), no spacer New - A1 New PSC Prototype,  Injection Pattern A (radial), 1mm spacer New - A3 New PSC Prototype,  Injection Pattern A (radial), 3mm spacer New - B0 New PSC Prototype,  Injection Pattern B (radial), no spacer New - B1 New PSC Prototype,  Injection Pattern B (swirl), 1mm spacer New - B3 New PSC Prototype,  Injection Pattern B (swirl), 3mm spacer New - C0 New PSC Prototype,  Injection Pattern C (penetrative), no spacer New - C1 New PSC Prototype,  Injection Pattern C (penetrative), 1mm spacer New - C3 New PSC Prototype,  Injection Pattern C (penetrative), 3mm spacer 2.2.6 Spark Plugs Due to the differences in design, different size spark plugs were used. A 14mm plug was used in the original PSC experiments, and a 8mm plug was used in the new PSC experi- ments. Their important qualities are mentioned in Figure 18 and Table 7. Though the sparkplugs and inserts are of different size preventing direct comparison, the optimal new hole pattern for the smaller insert could be recreated and used with the larger spark plug size. 18 !! "!#! $! Figure 18: Spark Plug Dimensions Table 7: Spark Plug Dimensions PSC DESIGN NEW ORIGINAL NGK # ER9EH ZFR6A-11 Size (mm) 8 14 a .030" .060" b .027" .044" c .060" .100" Electrode Style Flat V-Groove Image 2.3 DAQ and Instrumentation Interface The Ricardo Engine is fully equipped with low and high speed sampling instrumentation capabilities.  The low speed sampling, working at approximately 80 samples per minute, is used for determining fuel and air flow rates, component temperatures, and comprehensive exhaust emissions.  High speed sampling, functioning at 1440 samples per engine cycle, was used to measure the in-cylinder pressure.  A listing of the instrumentation specifications follows in Table 8. 19 Table 8: Ricardo Hydra Main Instrumentation Specifications Instrument Manufacturer Model Range Uncertainty Intake Air Flow Meriam 50MW 20-1.5 0-30 scfm ±1.0% of FS Intake Air and Exhaust Temperature Omega 1/8" K-Type -200 to 1250˚C ±0.75% FS Intake Manifold Pressure Differential Sensym (Honeywell) LX1803AZ 0-30 psia ±1.65% FS Pressure Transducer (Intake Air Flow Rate) AutTran 600 D-014 0-2" H2O ±1.0% FS Exhaust Relative Fuel-Air Ratio ECM 2400G RAFR = 0.4-10.0 ±0.9% FS In-Cylinder Pressure Transducer AVL QC33C 0-200 Bar ±0.25 Bar Main NG Mass Flow Meter MKS Instruments 1559A-100C-SV 0-100 slm ±0.6% of FS PSC NG Mass Flow Meter MKS Instruments 179A-24C-S3BM 0-20 slm ±0.6% of FS Optical Shaft Encoder (Engine Crank Angle / Speed) US Digital H1-360-1E 0-10,000rpm ± 5 rpm (speed) ± 1˚ (position) 2.4 Uncertainties It is necessary to determine the uncertainty of equations due to the propagation of the realization uncertainties.  The theory of the “root of the sum of the squares” allows the estimation of the overall experimental uncertainty WR. Equation 3: Experimental Uncertainty Where WX is the individual uncertainties and  is the sensitivity coefficient of R with respect to Xi. 20 Using BMEP as an example, Equation 4: Brake Mean Effective Pressure (N/m2) The experimental uncertainty is defined as: Equation 5: Experimental Uncertainty Where It will be observed herein that larger error bars are present at the higher RAFR values for BSFC, and emissions data.  These are typically when the COV has increased past 5%, and represents an increase in misfiring.  Although these higher than 5% COV values are not typically examined, they are included in the graphs for completeness of the trends post 5% COV. 2.5 Repeatability Repeatability, or test-retest reliability, is the variation of independent results obtained by one person while measuring the same subject using the same methods in the same 21 conditions, and is very important to the experiments presented here.  If the Ricardo baseline results are repeatable, then it is safe to assume that any changes while using the PSC insert technology will be due to the PSC technology itself.  This will provide a good signal of the results of parameter changes when using the PSC.  It is also assumed that the repeatability of any other test condition when using the PSC will be similar to the results from this baseline repeatability analysis.  Following is a series of results from 3 separate baseline test days. Visual inspection of Figures 19 to 24 show good agreement in general. There are a couple of exceptions, however.  One BSFC point in Figure 20 shows large error bars at RAFR = 1.53.  Also, the offsets present in the CH4, and to a lesser degree, tHC graphs (Figures 23 and 24).  The AVL emissions bench would sometimes have substantial CH4 and tHC calibration differences at the end of a testing day.  These calibration offsets are included in all CH4 and tHC graphs, and this offset problem needs to be dealt with in some manner in order to prevent this uncertainty in the future.  One proposal is to re-calibrate numerous times throughout the testing day.  This would greatly increase the required test time, but allow for more accurate numbers in the final data. Table 9: Repeatability Analysis for RAFR = 1.34 BMEP BSFC tHC CH4 NOX Average 6.04 241.93 11.10 5.59 5.12 Standard Deviation 0.09 4.61 0.30 1.35 0.56 95% Confidence Interval 0.11 5.21 0.33 1.52 0.63 Table 10: Repeatability Analysis for RAFR = 1.53 BMEP BSFC tHC CH4 NOX Average 5.39 243.13 13.68 7.56 1.16 Standard Deviation 0.34 15.72 0.45 1.68 0.27 95% Confidence Interval 0.38 17.78 0.51 1.91 0.31 22 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ Figure 19: Baseline Repeatability - Coefficient of Variability !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% Figure 20: Baseline Variability - BSFC 23 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% Figure 21: Baseline Variability - BMEP !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ Figure 22: Baseline Variability - Nitrous Oxide Generation 24 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& Figure 23: Baseline Variability - Total Hydrocarbon Generation !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ Figure 24: Baseline Variability - Methane Generation 25 Chapter 3: RESULTS AND DISCUSSION Baseline and Partially Stratified Charge tests were performed at minimum advance for best torque (MBT) at speeds of 1500, 2000 and 2500 RPM. The MBT style of deter- mining the test point is consistent with past work performed in the same lab using the same test engine. In each case, PSC injection fuel was always less than 4% of the overall fuel flow. Low and high PSC flow tests were performed for each RAFR value. Low flow rate is defined as anything up to 10g/hr, and high flow is any injection above that, typical- ly beginning at 14g/hr and ranging up to 24g/hr, depending on the engine speed. Once low flow ceased functioning at leaner RAFR values, higher flow values were added onto the test matrix. All tests were performed with the OMEGA solenoid described in Section 2.2.2. 3.1 Injection Timing A high speed camera in conjunction with schlieren technology was used to determine when and what happens with the injector and PSC combination. This allowed the quantification of injection start and end time with respect to both the signal start and du- ration. The signal duration had some small effect on injection delay, with visible start of injection varying from 5.7ms to 4.5 ms after signal start using pulse widths of 1.6ms to 1.85 ms, respectively. The change in signal length had a large effect on overall injection duration, and therefore total injected fuel, varying from 4g/hr to 30g/hr for pulse widths of 1.6ms to 1.85 ms, respectively. It was seen that upon viewable start of injection in the insert, it typically took between 2.5 and 3ms for the leading edge to reach the center of the viewing area, or where the elec- trodes would likely be located. Reynolds (Reynolds 2001) studied and described the effects of varying the PSC injection timing relative to the ignition, and this was not a major focus of this thesis. The timing used a PSC supply pressure of 15bar being exhausted to atmospheric condi- tions, so of course actual timing would be slightly different due to the pressure buildup in the combustion cylinder. 26  Figure 25: Schlieren SOI and EOI Examples !" #" $" %" &" '" (" )" #*''" #*(" #*('" #*)" #*)'" #*+" #*+'" #*," !" #$ %& !' " () &* +& (, $- *. (/0 12 ( 34-)$(5!,&6(/012( Figure 26: Effect of Pulse Width on Start of Injection 27 !" #" $!" $#" %!" %#" &!" &#" '!" '#" #!" $(##" $()" $()#" $(*" $(*#" $(+" $(+#" $(," !" # $ %& '( )*+ ,- ./ ) 01"2()$34'5)*67/) Figure 27: Omega Solenoid, Effect of Pulse Width on Fuel Flow Rate, 1500rpm !" #" $!" $#" %!" %#" &!" &#" '!" '#" #!" !" #" $!" $#" %!" %#" &!" &#" '!" '#" #!" !" # $ %& '( )*+ ,- ./ ) 012(3'0#1)45%&'0#1)*67/) Figure 28: Omega Solenoid, Fuel Flowrate vs Injection Duration, 1500rpm 28 Large fuel flow rate deviations are present using the Omega solenoid. This may be due to the presence of a sac volume after the solenoid valve. When the valve opens, the NG does not immediately get released. Instead, the pressure increases inside this sac volume until the pressure is sufficiently large, in which case the gas finally exits the injection nozzle. Another potential reason is that while the supply voltage from the ECU ‪to the injector was increased to ensure a rapid valve opening time, it does not close rapidly due to the lack of ability to control this aspect. 3.2 Ideal Tube Length Timing Tests Timing tests were performed with an "ideal length" PSC insert representation (Figure 29) to determine if there is a difference in gas injection duration versus the actual in use length, or "current length", and quantify this difference if it exists. This "ideal length" merely removed the 6 inches of extra capillary tube between the LEE micro valve and the insert itself. This test series was performed with the AFC series solenoid, which was not used extensively in the final tests due to its loss of repeatability. The results shown in Figure 30 demonstrate a significant timing improvement when injection tube lengths are minimized. Figure 31 also shows that there is a decrease in variability with the injection flow rate, and that the average flow rate stays in the same range. This improvement would likely carry across through the use of different injectors. This confirms the thought that removing "dead" volume after the solenoid valve does indeed increase the quality of the injection. Figure 29: Ideal Length PSC Insert 29 0 2 4 6 8 10 12 14 16 18 20 200 250 300 350 400 450 IN JE C TI O N  D U R AT IO N  (m s)  PULSE LENGTH (us) Ideal Tube Length Current Tube Length Figure 30: Ideal PSC Tube Length Injection Duration Analysis 0 10 20 30 40 50 60 200 250 300 350 400 450 M A SS  F LO W  R AT E (g /h r)  PULSE LENGTH (us) Ideal Tube Length Current Tube Length Figure 31: Ideal Tube Length Mass Flowrate Analysis 30 3.3 Baseline Test Results Baseline tests of the two general PSC setups were compared to quantify the plug and PSC geometry differences and their possible effect on engine performance. Baseline testing used the insert geometries to hold the spark plugs, but there was no PSC technology used. In all baseline cases, the original PSC insert design using the 14mm spark plug extends the lean limit of operation further than the new prototype PSC insert design using the 8mm spark plug, and an example of this can be seen in Figures 34. The effect can be attributed to a few reasons. Gap size, tip configuration, edge sharpness, and electrode projection into the chamber have been shown to have an effect on unburnt HC's and COV (Craver, Podiak and Miller 1970);(Burgett, Leptich and Sangwan 1972);(Alger et al. 2006). The differences between the original (14mm) PSC spark plug and the new (8mm) PSC spark plug are in good accordance with these past studies by Burgett et al. (1972), Craver et al. (1970) and Alger et al. (2006). The original 14mm plug has a larger electrode, wider gap, and a V-Groove in the cathode (for increased edges), and these items can ac- count for better unburnt tHC and COV values than the 8mm plug. Also, in both cases, the increased penetration (no spacers) provided similar or better COV and tHC results. This is apparent at all speeds with the new (8mm) PSC spark plug, but only becomes ap- parent at the highest speed of 2500rpm with the original (14mm) spark plug, as shown in Figures 41. The geometry of the PSC units can also affect ignition reliability. By examining general geometry differences of the PSC constraining the electrode, we can examine the flame kernel that forms when the spark plug is fired. Following are cross section images of both the original (14mm) PSC spark plug and the new (8mm) PSC spark plug with visual representations of the flame kernel and flame fronts. The original PSC has an opening di- ameter into the main combustion chamber of 10.6mm, whereas the new prototype has an opening diameter of 8.1mm. 31 Figure 32: Effect of Original PSC Geometry on Flame Propagation Figure 33: Effect of NEW PSC Geometry on Flame Propagation A smaller opening possibly minimizes the flame front surface area, therefore decreasing the exposure to ignitable fuel. Also, heat transfer at the PSC wall, which is, in effect, the same temperature as the cylinder wall, removes energy that would have been used for the 32 flame propagation. The effects of this on NOX formation can be observe in Figures 44 and 45 at the leanest RAFR points. 33 3.3.1 Coefficient of Variation !" #" $!" $#" %!" %#" $&'" $&'#" $&(" $&(#" $&#" $&##" $&)" $&)#" $&*" $&*#" !" # $%& '( $)* +$ ,-.,$ +,-./01."2"340501,/"2"!" +,-./01."2"340501,/"2"$" +,-./01."2"1.6"2"!" +,-./01."2"1.6"2"$" +,-./01."2"1.6"2"'" Figure 34: Baseline Coefficient of Variation of IMEP, 2000rpm !" #" $!" $#" %!" %#" $&'" $&'#" $&(" $&(#" $&#" $&##" $&)" $&)#" $&*" $&*#" !" # $%& '( $)* +$ ,-.,$ +,-./01."2"340501,/"2"!" +,-./01."2"340501,/"2"$" +,-./01."2"1.6"2"!" +,-./01."2"1.6"2"$" +,-./01."2"1.6"2"'" Figure 35: Baseline Coefficient of Variation of IMEP, 2500rpm 34 3.3.2 BSFC, Thermal Efficiency, and BMEP !!"# !$"# !%"# !&"# '""# '!"# '$"# '%"# ()'# ()'*# ()$# ()$*# ()*# ()**# ()%# ()%*# ()+# ()+*# !" #$ %&' () * +, -. % /0#/% ,-./012/#3#451612-0#3#"# ,-./012/#3#451612-0#3#(# ,-./012/#3#2/7#3#"# ,-./012/#3#2/7#3#(# ,-./012/#3#2/7#3#'# Figure 36: Baseline BSFC, 2000rpm !!"# !$"# !%"# !&"# '""# '!"# '$"# '%"# ()'# ()'*# ()$# ()$*# ()*# ()**# ()%# ()%*# ()+# ()+*# !" #$ %&' () * +, -. % /0#/% ,-./012/#3#451612-0#3#"# ,-./012/#3#451612-0#3#(# ,-./012/#3#2/7#3#"# ,-./012/#3#2/7#3#(# ,-./012/#3#2/7#3#'# Figure 37: Baseline BSFC, 2500rpm 35 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" )*+,-./,"0"12.3./*-"0"'" )*+,-./,"0"/,5"0"4" )*+,-./,"0"/,5"0"'" )*+,-./,"0"/,5"0"!" Figure 38: Baseline BMEP, 2000rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" )*+,-./,"0"12.3./*-"0"'" )*+,-./,"0"/,5"0"4" )*+,-./,"0"/,5"0"'" )*+,-./,"0"/,5"0"!" Figure 39: Baseline BMEP, 2500rpm 36 3.3.3 Emissions !"# $# "# %# &# '# ($# ("# (%# (&# ('# ()*# ()*+# ()%# ()%+# ()+# ()++# ()&# ()&+# (),# (),+# !" #$ %& '( )* + ,- ./ & 0120& -./01230#!#452623.1#!#$# -./01230#!#452623.1#!#(# -./01230#!#307#!#$# -./01230#!#307#!#(# -./01230#!#307#!#*# Figure 40: Baseline Total Hydrocarbon Emissions, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( )* + ,- ./ & 0120& ,-./012/"3"451612-0"3"!" ,-./012/"3"451612-0"3"'" ,-./012/"3"2/7"3"!" ,-./012/"3"2/7"3"'" ,-./012/"3"2/7"3")" Figure 41: Baseline Total Hydrocarbon Emissions, 2500rpm 37 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" ,-./012/"3"451612-0"3"'" ,-./012/"3"2/7"3"!" ,-./012/"3"2/7"3"'" ,-./012/"3"2/7"3")" Figure 42: Baseline Methane Emissions, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" ,-./012/"3"451612-0"3"'" ,-./012/"3"2/7"3"!" ,-./012/"3"2/7"3"'" ,-./012/"3"2/7"3")" Figure 43: Baseline Methane Emissions, 2500rpm 38 !" #" $" %" &" '" (" )" #*%" #*%'" #*&" #*&'" #*'" #*''" #*(" #*('" #*)" #*)'" ! " #$ %& '( ) *+ ,- $ ./0.$ +,-./01."2"340501,/"2"!" +,-./01."2"340501,/"2"#" +,-./01."2"1.6"2"!" +,-./01."2"1.6"2"#" +,-./01."2"1.6"2"%" Figure 44: Baseline Nitrous Oxide Emissions, 2000rpm !" #" $" %" &" '" (" )" #*%" #*%'" #*&" #*&'" #*'" #*''" #*(" #*('" #*)" #*)'" ! " #$ %& '( ) *+ ,- $ ./0.$ +,-./01."2"340501,/"2"!" +,-./01."2"340501,/"2"#" +,-./01."2"1.6"2"!" +,-./01."2"1.6"2"#" +,-./01."2"1.6"2"%" Figure 45: Baseline Nitrous Oxide Emissions, 2500rpm 39 3.4 Original PSC Low Flow Results Reynolds previously demonstrated that optimum increases in efficiency required flow rates of at least 14g/h, higher than the 1% of the total fuel flow at RAFR of 1.5, or about 7g/h at 1500rpm, presented in this section. These low flow tests were still performed in order to obtain comprehensive characterization of the original PSC insert and its differ- ences to the new PSC insert. 3.4.1 Lean Limit Extension !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"049":049";'<"4:":=/0"->"'(*"5-:5?" 7.8"3"451612-0"3"'"3"049":049";'<"4:":=/0"->"'(*"5-:5?" Figure 46: Original PSC, Coefficient of Variation, Low Flow, 2000rpm At 1500 rpm, there is no extension of the lean limit, and no improvement of COV values at the <5% baseline cases.  Figure 46 demonstrates that both spacer options extend the lean limit to similar values of RAFR = 1.575 - 1.58 at 2000rpm. The 1mm spacer extends the 2500rpm lean limit the furthest to RAFR of 1.58. 40 The BMEP results also confirm the stabilization at the lean limit for the 2000 and 2500rpm test cases. Table 11: Lean Limit Extension, Original PSC, Low Flow Speed (rpm) HomogenousRAFR at 5% COV Spacer Extended RAFR or 5% COV 1500 1.57 0 No COV Extension1 No COV Extension 2000 1.56 0 1.581 1.575 2500 1.54 0 1.561 1.58 3.4.2 BSFC, Thermal Efficiency, and BMEP Figure 47: Original PSC, BSFC, Low Flow, 2000rpm Improvements in BSFC are most apparent at 2000rpm and can be seen in Figure 47. At an RAFR of 1.54, the PSC insert with a 1mm spacer has an improvement in BSFC of ap- proximately 3.8% over the homogenous case, and with no spacer has a 1% improvement. For the 2500rpm test case, there is also a decrease in BSFC past the homogenous lean !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$451612-0$3$#$ 7.8$3$451612-0$3$#$3$049$:049$;*<$4:$:=/0$->$*+%$5-:5?$ 7.8$3$451612-0$3$*$3$049$:049$;*<$4:$:=/0$->$*+%$5-:5?$ 41 limit, in line with the PSC's ability to extend the lean limit. The benefit of the 1mm spac- er much more apparent when examining the BSFC graph at 2000rpm, than the COV data presented in Section 3.4.1. Since similar flow rates for the 0 and 1mm configurations are occurring, the decreased BSFC results could be due to increased power output, which points to more complete combustion. The 1mm spacer success is contrary to the data and information on spark plug projection presented in Section 3.3, which states that less spacers, and therefore more projection into the combustion chamber, provide better combustion results. One possible explanation is that the introduction of pure NG aimed directly at the electrode upon ignition could quench the flame, whereas offsetting the electrode from the PSC injection plane with the 1mm spacer could allow for more local mixing ahead of the electrode, and therefore a more easily ignitable area. Nakamura et al. (Nakamura et al. 1978) studied the effect of jet sizes on combustion by aiming a jet valve with different nozzle sizes directly at the spark plug. They found that weak jets and excessively strong jets did not aid the combustion process. The data from the PSC results herein could be a similar sign in that a strong jet is aimed directly at the electrode gap versus it being offset by the 1mm spacer. Data for 1500rpm was omitted, as there is no benefit from the use of the PSC insert tech- nology in low flow situations. 42 !"#$%& !'#(%& !'#$%& !)#(%& !)#$%& *(#(%& *(#$%& *+#(%& *+#$%& +#*& +#*$& +#,& +#,$& +#$& +#$$& +#-& +#-$& +#"& +#"$& !" #$ % & '( #) )* +* #, +- (./ 0( $&)$( ./012341&5&673834/2&5&(& 90:&5&673834/2&5&(&5&26;&<26;&=+%&6<&<>12&/?&+#$&7/<7@& 90:&5&673834/2&5&+&5&26;&<26;&=+%&6<&<>12&/?&+#$&7/<7@& Figure 48: Original PSC, Thermal Efficiency, Low Flow, 2000rpm Thermal efficiency results of Figure 48 confirm the BSFC results, with the largest im- provements at 2000rpm. At an RAFR of 1.54, the PSC insert with a 1mm spacer has a best improvement in thermal efficiency of approximately 1% over the homogenous case, and with no spacer has a 0.15% improvement. For the 2500rpm test case, there is also an increase in thermal efficiency past the homogenous lean limit. 43 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" 5+6"0"12.3./*-"0"4"0"-17"8-17"9':"18"8;,-"*<"'#$"2*82=" 5+6"0"12.3./*-"0"'"0"-17"8-17"9':"18"8;,-"*<"'#$"2*82=" Figure 49: Original PSC, BMEP, Low Flow, 2000rpm BMEP results demonstrate improvements in the 2000rpm test cases when compared to the homogenous <5% COV RAFR cutoff. These gains are listed in Table 12. The 2500rpm test cases experience no improvements. Table 12: BMEP Improvements, Original PSC, Low Flow Speed (rpm) Spacer % Improvement 2000 0 2 - 61 1 - 7 44 3.4.3 Emissions !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"562723.1"4"!" 8/9"4"562723.1"4"!"4"15:";15:"<#="5;";>01".?"#,'"6.;6@" 8/9"4"562723.1"4"#"4"15:";15:"<#="5;";>01".?"#,'"6.;6@" Figure 50: Original PSC, Nitrous Oxide Emissions, Low Flow, 2000rpm There are no improvements in NOx emissions with the low flow test cases. In the 2000rpm and 2500rpm test cases, there is a 13% to 76% gain in NOx. It is interesting to again note that the use of the 1mm spacer seems to be enabling more complete combus- tion, as the elevated NOX levels demonstrate. Table 13: % Change in NOx Emissions, Original PSC, Low Flow Speed (rpm) Homogenous NOx at5% COV (g/kw-hr) Spacer NOx at Lean Limit or 5% COV (g/kw-hr) % difference 1500 0.535 0 No COV Extension1 No COV Extension 2000 0.617 0 0.819 33% more1 1.09 76% more 2500 1.298 0 1.52 17% more1 1.47 13% more 45 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"562723.1"4"'" 8/9"4"562723.1"4"'"4"15:";15:"<#="5;";>01".?"#,+"6.;6@" 8/9"4"562723.1"4"#"4"15:";15:"<#="5;";>01".?"#,+"6.;6@" Figure 51: Original PSC, tHC Emissions, Low Flow, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"049":049";'<"4:":=/0"->"'(*"5-:5?" 7.8"3"451612-0"3"'"3"049":049";'<"4:":=/0"->"'(*"5-:5?" Figure 52: Original PSC, Methane Emissions, Low Flow, 2000rpm 46 Figures 51 and 52 confirm work as seen in past work by Reynolds (Reynolds, 2001), in which there are increases in total hydrocarbons and methane emissions when using the PSC. This increase is present up until the lean misfire limit, where homogenous misfires increase rapidly while PSC cases remain approximately consistent. Overall tHC and CH4 increases are shown in Table 14. The 1mm spacer demonstrates the least amount of in- creased tHC and CH4 in both 2000rpm and 2500rpm test cases. This again could be a sign of more complete combustion resulting from the offset of the injection plane to the spark plug electrode. Table 14: % Increase in tHC and CH4 Emissions, Original PSC, Low Flow Speed (rpm) Spacer % Increase tHC CH4 Min Max Min Max 2000 0 22.0 29.3 12.5 19.41 19.2 27.0 9.7 15.5 2500 0 26.6 29.2 21.6 23.31 21.9 22.0 17.9 18.3 47 3.5 Original PSC High Flow Results 3.5.1 Lean Limit Extension !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<#="4:":>/0"-?"'(%*"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<#="4:":>/0"-?"'(%*"5-:5@" Figure 53: Original PSC, Coefficient of Variation, High Flow, 2000rpm Extension of the lean limit is apparent at all 3 test speeds, and can be observed in Figures 53, 94, and 95.  Similar to the results from Section 3.4, the data is contradictory to the in- formation presented in Section 3.3, which is the use of the 1mm spacer gives more suc- cessful lean limit extensions in all cases.  1500rpm experiences no significant changes in BSFC. Values of 1.70 and 1.71 are obtained with the 0 and 1mm spacers, respectively, at 1500rpm.  Values of 1.68 and 1.70 are obtained with the 0 and 1mm spacers, respective- ly, at 2000rpm.  The details are summed up in Table 15. 48 Table 15: Lean Limit Extension, Original PSC, High Flow Speed (rpm) HomogenousRAFR at 5% COV Spacer Extended RAFR or 5% COV 1500 1.57 0 1.701 1.71 2000 1.56 0 1.681 1.70 2500 1.54 0 1.591 1.62 3.5.2 BSFC, Thermal Efficiency, and BMEP !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$451612-0$3$#$ 7.8$3$451612-0$3$#$3$9169$:04;$<!=$4:$:>/0$-?$*+'%$5-:5@$ 7.8$3$451612-0$3$*$3$9169$:04;$<!=$4:$:>/0$-?$*+'%$5-:5@$ Figure 54: Original PSC, BSFC, High Flow, 2000rpm The 1mm spacer use is again more beneficial than the use of no spacer, similar to results from section 3.4.2 Improvements in BSFC are most apparent at the 2000rpm test cases, as seen in Figure 54. At an RAFR of 1.54, the PSC insert with a 1mm spacer has an im- provement in BSFC of approximately 4% over the homogenous case, and the no spacer has a 1% improvement. For the 2500rpm test cases in Figure 96, there is also a decrease 49 in BSFC past the homogenous lean limit, in line with the PSC's ability to extend the lean limit.  1500rpm experiences no significant changes in BSFC. Thermal efficiency results confirm the BSFC results, with the most improvements being at 2000rpm. At an RAFR of 1.54, the PSC insert with a 1mm spacer has a best improve- ment in thermal efficiency of approximately 1.2% over the homogenous case, and the no spacer has a 0.15% improvement. For the 2500rpm test case, there is also an increase in thermal efficiency past the homogenous lean limit. !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" 5+6"0"12.3./*-"0"4"0"7.37"8-19":;<"18"8=,-"*>"'#&$"2*82?" 5+6"0"12.3./*-"0"'"0"7.37"8-19":;<"18"8=,-"*>"'#&$"2*82?" Figure 55: Original PSC, BMEP, High Flow, 2000rpm BMEP results demonstrate improvements in the 2000rpm test cases of Figure 55 when compared to the homogenous <5% COV RAFR cutoff . These gains are listed in Table 16. Table 16: BMEP Improvements, Original PSC, High Flow Speed (rpm) Spacer % Improvement 2000 0 2 - 2.51 1.5 - 4 50 3.5.3 Emissions !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"562723.1"4"!" 8/9"4"562723.1"4"!"4":27:";15<"=$>"5;";?01".@"#,('"6.;6A" 8/9"4"562723.1"4"#"4":27:";15<"=$>"5;";?01".@"#,('"6.;6A" Figure 56: Original PSC, Nitrous Oxide, High Flow, 2000rpm !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"562723.1"4"!" 8/9"4"562723.1"4"!"4":27:";15<"=$>"5;";?01".@"#,(%"6.;6A" 8/9"4"562723.1"4"#"4":27:";15<"=#,)>"5;";?01".@"#,(%"6.;6A" Figure 57: Original PSC, Nitrous Oxide, High Flow, 2500rpm 51 There are almost no improvements in NOX emissions with the high flow test cases, the exception being the 0mm spacer at 2500rpm from Figure 57.  Other values are very close to the homogenous limit NOX however, and "if it were decided to optimize the PSC tech- nology for minimum NOX, the spark could be retarded from MBT until peak cylinder pressures and temperatures were lowered sufficiently to achieve this end" (Reynolds, 2001).  Figure 56 is the clearest in demonstrating the increased NOX levels due to better combustion arising from the use of the 1mm spacer. Table 17: % Change in NOx Emissions, Original PSC, High Flow Speed (rpm) Homogenous NOx at5% COV (g/kw-hr) Spacer NOx at Lean Limit (g/kw-hr) % difference 1500 0.535 0 0.642 20% more1 0.542 1% more 2000 0.617 0 0.68 10% more1 0.687 11% more 2500 1.298 0 1.122 14% less1 1.584 22% more !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"562723.1"4"'" 8/9"4"562723.1"4"'"4":27:";15<"=(,#>"5;";?01".@"#,)+"6.;6A" 8/9"4"562723.1"4"#"4":27:";15<"=(,#>"5;";?01".@"#,)+"6.;6A" Figure 58: Original PSC, Total Hydrocarbons, High Flow, 1500rpm 52 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<)('="4:":>/0"-?"'(%*"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<)('="4:":>/0"-?"'(%*"5-:5@" Figure 59: Original PSC, Methane, High Flow, 1500rpm Overall tHC and CH4 increases are shown in Table 18 and have increases in all cases when compared to homogenous test cases.  As in the low flow cases from Section 3.4.3, the 1mm spacer demonstrates the least amount of increased tHC and CH4 in most test cases. Figures 58 and 59 are good examples of this. Table 18: % Increase in tHC and CH4 Emissions, Original PSC, High Flow RPM Spacer % Increase tHC CH4 Min Max Min Max 1500 0 40.7 43.9 31.4 34.41 35.0 37.0 29.5 32.3 2000 0 28.9 35.8 20.7 29.31 25.4 33.4 18.7 24.4 2500 0 31.5 36.9 26.9 31.91 27.5 32.5 25.4 29.7 53 3.6 New PSC Low Flow Results 3.6.1 Lean Limit Extension !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"074"8074"9':"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-'"3"074"8074"9':"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-)"3"074"8074"9':"78"8;/0"-<"'(*"=-8=>" Figure 60: New PSC-A, Coefficient of Variation, Low Flow, 1500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"074"8074"9!(+*:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",'"3"074"8074"9':"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",)"3"074"8074"9':"78"8;/0"-<"'(*"=-8=>" Figure 61: New PSC-B, Coefficient of Variation, Low Flow, 1500rpm 54 COV decrease and extension of the lean limit is apparent at all 3 test speeds. The A in- jection pattern provides more stability in more cases. The 3mm spacer provided the best extension of the lean limit in 3 of the 6 injection pattern / speed combinations, the most significant increase being in conjunction with the A injection pattern to achieve an ex- tended COV of 1.62, as seen in Figure 60 and compared to Figure 61, the B injection pat- tern at 1500rpm. One could remark that the extended COV values are really quite close to one another, and as seen in the repeatability study, can vary a small amount from day to day.  This was also observed in Brown's repeatability analysis (Brown 2003, 47-52). Table 19: Lean Limit Extension, New PSC, Low Flow Speed (rpm) Homogenous RAFRat 5% COV Spacer Extended RAFR or 5% COV  cutoff A Pattern B Pattern 1500 1.57 0   1.575 No Extension 1 1.58 No Extension 3 1.62 1.58 2000 1.47 0 1.59 1.59 1 1.58 1.54 3 1.57 1.58 2500 1.46 0 1.56 1.53 1 1.58 1.54 3 1.56 1.57 55 3.6.2 BSFC, Thermal Efficiency, and BMEP !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$074$8074$9*:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-*$3$074$8074$9*:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-"$3$074$8074$9*:$78$8;/0$-<$*+%$=-8=>$ Figure 62: New PSC-A, BSFC, Low Flow, 1500rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$,#$3$074$8074$9#+(%:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$,*$3$074$8074$9*:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$,"$3$074$8074$9*:$78$8;/0$-<$*+%$=-8=>$ Figure 63: New PSC-B, BSFC, Low Flow, 1500rpm 56 !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$074$8074$9#+):$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-*$3$074$8074$9#+):$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-"$3$074$8074$9#+):$78$8;/0$-<$*+%$=-8=>$ Figure 64: New PSC-A, BSFC, Low Flow, 2000rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$,#$3$074$8074$9#+):$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$,*$3$074$8074$9#+(%:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$,"$3$074$8074$9#+(%:$78$8;/0$-<$*+%$=-8=>$ Figure 65: New PSC-B, BSFC, Low Flow, 2000rpm 57 !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$074$8074$9#+(%:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-*$3$074$8074$9#+(:$78$8;/0$-<$*+%$=-8=>$ 5.6$3$2/4$3$-"$3$074$8074$9#+':$78$8;/0$-<$*+%$=-8=>$ Figure 66: New PSC-A, BSFC, Low Flow, 2500rpm Improvements in BSFC and thermal efficiency are most apparent at the 1500 and 2000rpm test cases, with no improvements at the 2500rpm test cases. The PSC insert shows improvements both in BSFC before the homogenous lean limit and at the equiva- lent of the new extended lean limit. 2500rpm BSFC graphs are shown for pattern A only, as pattern B is very similar and also shows no improvements with respect to BSFC. Table 20 summarizes the BSFC and thermal efficiency improvements demonstrated for 1500 and 2000rpm, with no gains at 2500rpm. The B1 pattern is best, although marginal- ly, in 1500rpm cases with a 1.3% BSFC improvement, and the B0 is best in 2000rpm test cases with a 5.5% improvement in BSFC. In examining Figures 62 to 66, it is difficult to determine a combination resulting in best BSFC values. The B pattern does provide better BSFC values overall, as seen in Table 20, and its best combination is with the use of the 1mm spacer and use of no spacer for 1500rpm and 2000rpm test cases, respectively. Since the nozzle ports in pattern B are not aimed directly at the electrode, it could be that the penetration depth is again of benefit. 58 Table 20: New PSC, Low Flow - BSFC and Thermal Efficiency Improvements Speed (rpm) Spacer A Pattern B Pattern BSFC ThermalEfficiency BSFC Thermal Efficiency 1500 0 No Improvement 0.13% No Improvement 1 0.5% 0.09% 1.3% 0.35% 3 0.4% 0.06% 0.5% 0.12% 2000 0 3.83% 1.62% 5.5% 1.6% 1 5.5% 1.1% 4.5% 1.3% 3 3.3% 0.92% 4.0% 1.1% !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"-51"6-51"72#89"56"6:,-"*;"'#$"<*6<=" 3+4"0"/,1"0"*'"0"-51"6-51"72#89"56"6:,-"*;"'#$"<*6<=" 3+4"0"/,1"0"*!"0"-51"6-51"72#89"56"6:,-"*;"'#$"<*6<=" Figure 67: New PSC-A, BMEP, Low Flow, 2000rpm 59 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0")2"0"-51"6-51"72#89"56"6:,-"*;"'#$"<*6<=" 3+4"0"/,1"0")'"0"-51"6-51"72#($9"56"6:,-"*;"'#$"<*6<=" 3+4"0"/,1"0")!"0"-51"6-51"72#($9"56"6:,-"*;"'#$"<*6<=" Figure 68: New PSC-B, BMEP, Low Flow, 2000rpm Table 21 summarizes the BMEP improvements demonstrated for 2000 and 2500rpm test cases when compared to the homogenous <5% COV RAFR cutoff. The B0 pattern is best in both the 2000rpm and 2500rpm test cases with 3.6 - 9.7% and 3.1 - 3.3% im- provements, respectively. Figures 67 and 68 provide a good example of the BMEP curves. Table 21: New PSC, Low Flow - BMEP Improvements Speed (rpm) Spacer % Improvement RangeA Pattern B Pattern 2000 0 1.1 - 5.5 3.6 - 9.7 1 1.5 - 6.5 2.4 - 7.6 3 2.6 - 7.6 2.8 - 7.6 2500 0 0.6 - 1.0 3.1 - 3.3 1 1.8 - 2.2 1.6 - 3.3 3 2.5 1.9 - 2.5 60 3.6.3 Emissions !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4".!"4"185"9185":!,)';"89"9<01".="#,'">.9>?" 6/7"4"305"4".#"4"185"9185":!,);"89"9<01".="#,'">.9>?" 6/7"4"305"4".%"4"185"9185":!,(;"89"9<01".="#,'">.9>?" Figure 69: New PSC-A, Nitrous Oxide Emissions, Low Flow, 2500rpm !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4"-!"4"185"9185":!,(;"89"9<01".="#,'">.9>?" 6/7"4"305"4"-#"4"185"9185":!,(;"89"9<01".="#,'">.9>?" 6/7"4"305"4"-%"4"185"9185":!,(;"89"9<01".="#,'">.9>?" Figure 70: New PSC-B, Nitrous Oxide Emissions, Low Flow, 2500rpm 61 Improvements in NOX are only seen at the 2500rpm test cases of Figures 69 and 70, and the best overall gains are with the use of the B0 injection pattern with a value of 1.2 g/ kw-hr. Mostly, the B injection pattern decreases NOX the most or is very close to the low- er A injection pattern values. Table 22: New PSC NOx Differences, Low Flow Speed (rpm) Homogenous NOx at 5% COV (g/kw-hr) Spacer A Injection Pattern B Injection Pattern NOx at Lean Limit or 5% COV (g/kw-hr) % difference NOx at Lean Limit or 5% COV (g/kw-hr) % difference 1500 1.09 0 1.39 27% more No COV extension 1 1.361 25% more No COV extension 3 1.178 8% more 1.119 3% more 2000 0.662 0 1.134 71% more 0.959 35% more 1 1.119 69% more 1.142 72% more 3 1.017 53% more 1.046 58% more 2500 2.57 0 1.73 33% less 1.2 53% less 1 1.37 46% less 1.74 32% less 3 1.13 56% less 1.57 21% less !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4".'"4"185"9185":',%+;"89"9<01".="#,+">.9>?" 6/7"4"305"4".#"4"185"9185":',%;"89"9<01".="#,+">.9>?" 6/7"4"305"4".("4"185"9185":',);"89"9<01".="#,+">.9>?" Figure 71: New PSC-A, Total Hydrocarbons, Low Flow, 2500rpm 62 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"185"9185":',);"89"9<01".="#,+">.9>?" 6/7"4"305"4"-#"4"185"9185":',);"89"9<01".="#,+">.9>?" 6/7"4"305"4"-("4"185"9185":',);"89"9<01".="#,+">.9>?" Figure 72: New PSC-B, Total Hydrocarbons, Low Flow, 2500rpm tHC and CH4 values increase in almost every test case with the use of the PSC insert as seen in Figures, the exception being 2500rpm and the B1 setup, where a decrease in CH4 of between 1.1% to 3.2% occurs. The B style test results have consistently less average increases of tHC and CH4 increases than the A style head, as demonstrated by comparing the values from Tables 25 and 26, with more specific details available in Tables 23 and 24. This could be a sign of more complete combustion resulting from better mixing thanks to the swirl effect of pattern B, which has been studied and shown to promote mixing between the air and injected fuel (Heywood 1988, 342-343), and can indeed pro- mote the burning rate (Zhang 1995). One could liken the comparison of patterns A and B to the work performed by Gete (Gete 1991, 62), in which he concluded that offset config- urations of jet ports (pattern B) "generated more slowly decaying flow" than the radially opposed jet arrangements (pattern A), which "were not effective because of the counter flow resulting in quick turbulence breakdown and dissipation". 63 Table 23: % Change in tHC and CH4 Emissions, New PSC-A, Low Flow Speed (rpm) InjectionPattern % Increase tHC CH4 Min Max Min Max 1500 A0 23.5 24.7 33.1 33.6 A1 10.6 11.7 21.2 25.2 A3 20.0 20.6 17.3 21.5 2000 A0 20.2 25.7 32.5 38.8 A1 9.9 14.5 28.3 34.9 A3 26.6 31.0 25.0 28.6 2500 A0 20.2 21.9 38.3 47.8 A1 11.1 15.8 31.9 45.2 A3 23.9 25.4 24.5 36.2 Table 24: % Change in tHC and CH4 Emissions, New PSC-B, Low Flow Speed (rpm) InjectionPattern % Increase tHC CH4 Min Max Min Max 1500 B0 18.2 21.3 10.7 15.0 B1 16.3 17.7 0.4 3.9 B3 12.7 13.6 12.0 18.7 2000 B0 16.2 16.9 2.6 5.7 B1 17.4 22.9 0.5 4.5 B3 13.0 14.8 6.1 7.1 2500 B0 16.7 19.7 4.3 4.5 B1 8.6 12.3 -1.1 -3.2 B3 15.2 19.3 21.3 23.7 Table 25: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-A, Low Flow Speed (rpm) Average % IncreasetHC CH4 1500 18.5 25.3 2000 21.3 31.4 2500 19.7 37.3 64 Table 26: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-B, Low Flow Speed (rpm) Average % IncreasetHC CH4 1500 16.6 10.1 2000 16.9 4.4 2500 15.3 8.3 65 3.7 New PSC High Flow Results 3.7.1 Lean Limit Extension !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";'(+<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";'(+*<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";'(%<":9"9=/0"->"'(%"?-9?@" Figure 73: New PSC-A, Coefficient of Variation, High Flow, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";#(+*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";'(+*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";'(+*<":9"9=/0"->"'(**"?-9?@" Figure 74: New PSC-B, Coefficient of Variation, High Flow, 2000rpm 66 Good examples of COV decrease and extension of the lean limit is apparent at all 3 test speeds, and are seen in Figures 73 and 74. Lean limits are much more extended using higher gas flow than lower gas flow, up to values of RAFR = 1.67 in multiple instances. This time, the B injection pattern provides more stability in 8 out of 9 cases. In 4 of the 6 nozzle pattern and speed combinations, the 0mm spacer provides the best extension. The BMEP results also confirm these extensions of the lean limit. One could theorize that a positive combination arises from the spark plug chamber penetration as discussed in Sec- tion 3.3, and swirl effect of the B injection pattern, as discussed in Section 3.6.3. Table 27: Lean Limit Extension, New PSC, Low Flow Speed (rpm) Homogenous RAFR at 5% COV Spacer Extended RAFR or 5% COV cutoff A Pattern B Pattern 1500 1.57 0 1.63 1.65 1 1.64 1.67 3 1.64 1.67 2000 1.47 0 1.63 1.67 1 1.60 1.63 3 1.59 1.60 2500 1.46 0 1.62 1.60 1 1.57 1.58 3 No extension 1.53 67 3.7.2 BSFC, Thermal Efficiency, and BMEP !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$7187$90:4$;*+(<$:9$9=/0$->$*+'$?-9?@$ 5.6$3$2/4$3$-*$3$7187$90:4$;*+(%<$:9$9=/0$->$*+'$?-9?@$ 5.6$3$2/4$3$-"$3$7187$90:4$;*+'<$:9$9=/0$->$*+'$?-9?@$ Figure 75: New PSC-A, BSFC, High Flow, 2000rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$,#$3$7187$90:4$;!+(%<$:9$9=/0$->$*+'%$?-9?@$ 5.6$3$2/4$3$,*$3$7187$90:4$;*+(%<$:9$9=/0$->$*+'%$?-9?@$ 5.6$3$2/4$3$,"$3$7187$90:4$;*+(%<$:9$9=/0$->$*+%%$?-9?@$ Figure 76: New PSC-B, BSFC, High Flow, 2000rpm 68 Improvements in BSFC are apparent at the 1500rpm and 2000rpm test cases, with no im- provements at the 2500rpm test cases. The PSC insert shows improvements both in BSFC before the homogenous lean limit and at the equivalent of the new extended lean limit, as in Figures 75 and 76. Table 28 summarizes the BSFC and thermal efficiency improvements demonstrated for 1500 and 2000rpm. The B3 pattern has the best at 1500rpm with a 1.2% improvement in BSFC. At 2000rpm, the A1 and B0 patterns are very close with 5.7% and 5.5% improve- ments in BSFC. Table 28: New PSC, High Flow - BSFC and Thermal Efficiency Improvements Speed (rpm) Spacer A Pattern B Pattern BSFC ThermalEfficiency BSFC Thermal Efficiency 1500 0 No Improvement 0.20% 0.06% 1 1.1% 0.29% 0.83% 0.19% 3 No Improvement 1.2% 0.31% 2000 0 4.5% 1.3% 5.5% 1.6% 1 5.7% 1.7% 4.5% 1.4% 3 2.7% 0.73% 4.0% 1.3% !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"5.65"7-81"9'#(:"87"7;,-"*<"'#&"=*7=>" 3+4"0"/,1"0"*'"0"5.65"7-81"9'#($:"87"7;,-"*<"'#&"=*7=>" 3+4"0"/,1"0"*!"0"5.65"7-81"9'#&:"87"7;,-"*<"'#&"=*7=>" Figure 77: New PSC-A, BMEP, High Flow, 2000rpm 69 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0")2"0"5.65"7-81"9:#($;"87"7<,-"*="'#&$">*7>?" 3+4"0"/,1"0")'"0"5.65"7-81"9'#($;"87"7<,-"*="'#&$">*7>?" 3+4"0"/,1"0")!"0"5.65"7-81"9'#($;"87"7<,-"*="'#$$">*7>?" Figure 78: New PSC-B, BMEP, High Flow, 2000rpm Table 29 summarizes the BMEP improvements demonstrated when compared to the ho- mogenous <5% COV RAFR cutoff. At 2000rpm, as seen in Figures 77 and 78, the B0 pattern has the best improvement with 4.2 - 9.7% change in BMEP. At 2500, the B0 pat- tern is again the best with 3.2 - 4.3% improvement. In these cases, the B injection pattern generally provides better BMEP results. Table 29: New PSC, High Flow - BMEP Improvements Speed (rpm) Spacer % ImprovementA Pattern B Pattern 1500 0 None None 1 None 0.9 - 6.1 3 None 0.9 - 6.1 2000 0 1.4 - 6.5 4.2 - 9.7 1 3.7 - 8.2 2.3 - 7.6 3 1.4 - 5.5 3.4 - 7.6 2500 0 0.6 - 1.0 3.2 - 4.3 1 1.5 - 2.6 2.8 - 4.5 3 1.9 - 2.7 1.9 - 3.5 70 3.7.3 Emissions !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4".!"4"8298":1;5"<#,)=";:":>01".?"#,("@.:@A" 6/7"4"305"4".#"4"8298":1;5"<#,)'=";:":>01".?"#,("@.:@A" 6/7"4"305"4".%"4"8298":1;5"<#,(=";:":>01".?"#,("@.:@A" Figure 79: New PSC-A, Nitrous Oxide, High Flow, 2000rpm !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4"-!"4"8298":1;5"<$,)'=";:":>01".?"#,('"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<#,)'=";:":>01".?"#,('"@.:@A" 6/7"4"305"4"-%"4"8298":1;5"<#,)'=";:":>01".?"#,''"@.:@A" Figure 80: New PSC-B, Nitrous Oxide, High Flow, 2000rpm 71 When compared to the homogenous lean limit, improvements in NOX are seen at the 1500 and 2500rpm test cases. Mostly, the B injection pattern decrease NOX the most or are very close to the lower A injection pattern values. At 1500rpm, the best improvement in NOX is seen with the A3 pattern for a 44% decrease. At 2000rpm, the best result is the B1 pattern with a 1% gain in NOX. At 2500rpm, the best improvement in NOX is seen with the B1 pattern for a 71% decrease. These details are summed up in Table 30. Test cases of 2000rpm can be seen in Figures 79 and 80. Table 30: New PSC NOx Differences, High Flow Speed (rpm) Homogenous NOX at 5% COV (g/kw-hr) Spacer A Pattern B Pattern NOX at Lean Limit or 5% COV (g/kw-hr) % difference NOX at Lean Limit or 5% COV (g/kw-hr) % difference 1500 1.09 0 1.03 5% less 1.01 7% less 1 0.629 42% less 0.713 35% less 3 0.614 44% less 0.68 38% less 2000 0.66 0 1.08 63% more 0.959 35% more 1 0.955 44% more 0.672 1% more 3 0.451 32% more 0.75 13% more 2500 2.57 0 1.39 46% less 0.983 62% less 1 1.47 43% less 0.736 71% less 3 2.24 13% less 1.59 38% less tHC and CH4 values increase in every test case with the use of the PSC insert. The B style test results have consistently less average increases of CH4 increases than the A style head, and the average tHC increases are very close to the A pattern increases. These can be quantified by examining Tables 33 and 34, where the B pattern has average tHC and CH4 increases of 26.3% and 17.0%, respectively, while the A pattern has average tHC and CH4 increases of 24.7% and 37.3%, respectively. The details can be seen in Ta- bles 31 and 32. 72 Table 31: % Change in tHC and CH4 Emissions, New PSC-A, High Flow Speed (rpm) InjectionPattern % Increase tHC CH4 Min Max Min Max 1500 A0 35.0 35.7 46.6 47.6 A1 18.2 22.0 33.6 37.0 A3 27.4 27.8 23.8 28.0 2000 A0 23.4 29.0 36.1 42.0 A1 14.3 16.8 34.1 40.0 A3 29.8 35.0 35.4 36.0 2500 A0 23.3 24.9 40.7 42.1 A1 14.6 17.6 37.9 39.8 A3 27.1 28.1 28.4 29.0 Table 32: % Change in tHC and CH4 Emissions, New PSC-B, High Flow Speed (rpm) InjectionPattern % Increase tHC CH4 Min Max Min Max 1500 B0 28.3 31.4 21.2 28.0 B1 30.7 32.0 10.7 16.9 B3 22.3 23.5 25.2 27.1 2000 B0 23.0 29.9 9.3 15.2 B1 23.8 29.0 6.8 12.1 B3 24.6 27.6 29.1 29.3 2500 B0 20.0 23.3 7.9 9.3 B1 13.9 14.9 2.2 2.6 B3 19.5 22.4 26.1 27.2 Table 33: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-A, High Flow Speed (rpm) Average % IncreasetHC CH4 1500 27.7 36.1 2000 24.7 37.3 2500 22.6 36.3 73 Table 34: Average % Change in tHC and CH4 Emissions Based on Speed, New PSC-B, High Flow Speed (rpm) Average % IncreasetHC CH4 1500 28.0 21.5 2000 26.3 17.0 2500 19.0 12.6 3.8 New PSC - AFC Injector Tests One set of tests were performed at 2000rpm using the AFC solenoid. As mentioned, the AFC solenoid suffered from premature failure, most likely due to the high voltage being supplied to this component regularly powered by 12V. 3.8.1 Lean Limit Extension !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7'()8"9:":;/0"-<"'(*"=-:=>" 5.6"3"2/4"3",!"3"7#('8"9:":;/0"-<"'(*"=-:=>" 5.6"3"2/4"3"6!"3"7'(&8"9:":;/0"-<"'(*"=-:=>" Figure 81: New PSC, Coefficient of Variation, AFC Solenoid, 2000rpm Extension of the lean limit using the AFC solenoid is present with all 3 injection patterns. The best extensions occurs when using the C0 penetrative style head, as seen in Table 35 74 and Figure 81. This could arise from the generation of turbulence not only locally around the spark plug electrode, but also within the remainder of the combustion chamber. Table 35: Lean Limit Extension, New PSC, AFC Solenoid Speed (rpm) Homogenous RAFR at 5% COV Injection Pattern Extended RAFR or 5% COV 2000 1.47 A0 1.58 B0 1.56 C0 1.61 3.8.2 BSFC, Thermal Efficiency, and BMEP !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$7*+"8$9:$:;/0$-<$*+%$=-:=>$ 5.6$3$2/4$3$,#$3$7!+*8$9:$:;/0$-<$*+%$=-:=>$ 5.6$3$2/4$3$6#$3$7*+)8$9:$:;/0$-<$*+%$=-:=>$ Figure 82: New PSC, BSFC, AFC Solenoid, 2000rpm Results with the AFC solenoid show that the B0 injection pattern creates the greatest im- provements in BSFC with a value of 6.6%, as shown in Figure 82 and in Table 36. 75 Table 36: BSFC Improvements, New PSC, AFC Solenoid Speed (rpm) Spacer BSFC 2000 A0 5.8% B0 6.6% C0 5.0% !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"5'#!6"78"89,-"*:"'#$";*8;<" 3+4"0"/,1"0")2"0"5=#'6"78"89,-"*:"'#$";*8;<" 3+4"0"/,1"0"42"0"5'#>6"78"89,-"*:"'#$";*8;<" Figure 83: New PSC, BMEP, AFC Solenoid, 2000rpm The best results for BMEP are again with the B0 injection pattern, with an improvement of 2.3% - 7.9%, as shown in Figure 83 and 37. Table 37: BMEP Improvements, New PSC, AFC Solenoid Speed (rpm) Injection Pattern % Improvement 2000 A0 1.7 - 7.7 B0 2.3 - 7.9 C0 0.1 - 5.7 76 3.8.3 Emissions !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4".!"4"8#,%9":;";<01".="#,'">.;>?" 6/7"4"305"4"-!"4"8$,#9":;";<01".="#,'">.;>?" 6/7"4"305"4"7!"4"8#,*9":;";<01".="#,'">.;>?" Figure 84: New PSC, Nitrous Oxide Emissions, AFC Solenoid, 2000rpm Looking at NOX in Figure 84 and Table 38, the C0 pattern has the smallest increase by only 10% thanks to its extended lean limit. Table 38: NOx Differences, New PSC, AFC Solenoid Speed (rpm) Homogenous NOx at5% COV (g/kw-hr) Injection Pattern NOx at Lean Limit or 5% COV (g/kw-hr) % difference 2000 0.66 A0 1.08 93% more B0 1.38 108% more C0 0.726 10% more 77 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4".'"4"8#,(9":;";<01".="#,+">.;>?" 6/7"4"305"4"-'"4"8&,#9":;";<01".="#,+">.;>?" 6/7"4"305"4"7'"4"8#,!9":;";<01".="#,+">.;>?" Figure 85: New PSC, tHC Emissions, AFC Solenoid, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7'()8"9:":;/0"-<"'(*"=-:=>" 5.6"3"2/4"3",!"3"7#('8"9:":;/0"-<"'(*"=-:=>" 5.6"3"2/4"3"6!"3"7'(&8"9:":;/0"-<"'(*"=-:=>" Figure 86: New PSC, Methane Emissions, AFC Solenoid, 2000rpm 78 At the RAFR values of 1.56-1.58, where the A0 and B0 have their last values, the C0 pat- tern has a best CH4 value, and a tHC value in between the A0 and B0 values. At the C0 extended lean limit, the tHC and CH4 increase dramatically due to the increases in misfiring. Table 39: tHC and CH4 Differences, New PSC, AFC Solenoid Speed (rpm) InjectionPattern % Increase tHC CH4 Min Max Min Max 2000 A0 9.5 13.5 34.1 43.1 B0 12.3 13.5 18.1 18.4 C0 19.4 41.9 29.1 57.0 3.9 Natural Gas Dead Volume As has been noted, there is an increase in CH4 when using the PSC insert. It is very like- ly that this is due to a portion of natural gas being trapped in the section between the in- jector and the PSC insert injection holes during combustion. Once combustion is com- plete, this unburnt gas is exhausted and read by the emissions bench. An approximation of this gas follows for 3 different cases using the non-ideal gas law. All cases are at a value of 100F, 1500rpm, and use the corresponding brake power in kW from the original PSC insert tests with no spacer. A schematic from the injection solenoid valve to the PSC Insert is included in Figure 87 for clarity. Figure 87: Injection Schematic 79 PV = nZRT   Equation 6: Non-Ideal Gas Law 1. The gas pressure is at 15 Bar, and the section from the LEE micro check valve to the insert injection area is approximated. 2. The gas pressure is at 15 Bar, and the entire section from the injector to the insert injection area is approximated. Table 40: Dead Volume Calculation Case Pressure(bar) Z Factor Calculated Density (kg/m3) Gas (g/hr) 1 15 0.975 10.01 26.9 2 15 0.975 10.01 114.1 Table 41: Dead Volume CH4 Contribution Calculation (g/kw-hr) Brake Power (kW) 3.52 3.25 3.05 2.91 2.80 2.71 2.62 Lambda 1.32 1.43 1.53 1.58 1.63 1.67 1.70 Case 1 7.65 8.27 8.83 9.25 9.60 9.92 10.26 Case 2 32.45 35.09 37.45 39.24 40.73 42.06 43.51 Though this is simply an approximation, it demonstrates that there can be significant CH4 leftover in the experimental setup after combustion. This in turn contributes to the in- creased count when using the PSC, although it is unlikely that all of the CH4 observed is contributed from this, as case 2 would infer. 80 Chapter 4: CONCLUSIONS 4.1 Conclusions Partially Stratified Charge insert technology is one of many ideas that can be used to extend the lean limit of operation.  This is accomplished by introducing a small quantity of pure natural gas, usually on the order of 5% or less of the overall fuel quantity, in the local area of the spark plug electrode, whereas the rest of the mixture in the combustion cylinder is homogenous and very lean.  This creates opportunity for more stable initial ignition, which in turn increases the likelihood of flame propagation throughout the combustion cylinder.  It aims to do this as it is easier to fabricate new components that accept standard sparkplugs than modifying existing sparkplugs for use. The objective of this thesis was to examine the capability of the PSC inserts to extend the lean misfire limit, decrease NOX emissions, and improve BSFC and BMEP results.  It also aimed to determine the effect of offsetting the injection location from the spark plug electrode, and to determine which of 3 injection nozzle patterns function the best. It was found that PSC insert technology is able to extend the lean limit of operation in all speed cases, including 1500rpm, whereas modified spark plug technology created by Reynolds only improved operation at 2000 and 2500rpm.  This extended lean limit is successful in decreasing NOX values.  This comes with a trade-off however, as lower temperatures resulting from the lean fuel mixture result in large increases in unburnt CH4. If desired, the ignition timing could be adjusted from MBT to a position to either decrease NOX even more or attempt to decrease the amount of unburnt CH4,. The following conclusions have been made after investigation of the data presented herein: 1. Concerning the new PSC insert using the 8mm spark plug with the Omega solenoid, the best results in BMEP,  NOX, tHC and CH4 levels are accomplished through the use of the B style injection pattern.  BSFC results are very similar in both A and B 81 pattern injections.   The best results obtained from the B-style injection pattern could be a result of the ideas from section 3.6.  More complete combustion resulting from better mixing thanks to the swirl effect, which has been studied and shown to promote mixing between the air and injected fuel (Heywood 1988, 342-343), and can indeed promote the burning rate (Zhang 1995).  Also, it could be that the offset configurations of jet ports (pattern B) "generated more slowly decaying flow" than the radially opposed jet arrangements (pattern A), which "were not effective because of the counter flow resulting in quick turbulence breakdown and dissipation" (Gete 1991, 62). It is difficult to decide on an optimal spacer height to associate with the best injection pattern, as both the 1mm and 3mm spacers increase positive results in similar fashions.  Using the B0 PSC setup at 2000rpm, it is possible to achieve a relative air fuel ratio of 1.67 versus the homogenous limit of 1.47, and BMEP improvements of up to 9.7%. Using the A1 PSC setup, it was possible to achieve BSFC improvements of 5.7%.  Using the B1 PSC setup at 2000rpm at the extended relative air-fuel ratio location, NOX were matched to the homogenous lean limit values.  At 1500rpm and 2500rpm, it was possible to decrease the NOX values by up to 44% and 71%, using the A1 and B1 PSC setups, respectively. 2. Concerning the original 14mm spark plug and the 18mm insert designed by David Gorby, the best gains are mostly consistently achieved when using a 1mm spacer to offset the location of the electrode in relation to the injected gas.  As mentioned in section  3.4, it could be that the introduction of pure NG aimed directly at the electrode upon ignition could quench the flame, whereas offsetting the electrode from the PSC injection plane with the 1mm spacer could allow for more local mixing ahead of the electrode, and therefore a more easily ignitable area.  Using the 1mm spacer at 2000rpm, it is possible to achieve a relative air fuel ratio of 1.70 versus the homogenous limit of 1.56, BSFC and thermal efficiency improvements of 4%, and BMEP improvements of up to 4%.  At the extended relative air-fuel ratio, NOX values were higher than, but still very close to, the homogenous lean limit values. 3. High flow fuel setups, ranging from 14g/hr up to 24g/hr, consistently resulted with more extended lean limits, better BSFC and BMEP values in all PSC test cases, as seen previously with Reynolds (Reynolds 2001). 4. As seen in sections 3.1 and 3.2, infeed tube length between the injector and the insert injection location has a large effect on mass flow and injection duration.  A shorter length decreases the mass flow duration.  It has also been noted in section 3.9 that injection tube dead volume between the solenoid and the PSC injection location could 82 be a significant contributor to post combustion CH4 levels. 5. Initial testing of the C style injection pattern using the AFC injection solenoid showed promise.  The C0 setup at 2000rpm extended the lean limit to 1.61 from the homogenous lean limit of 1.47, and decreased the NOX the most to a value only 10% above the homogenous.  With these preliminary tests however, the B style injection pattern still had the best results in BSFC and BMEP. 4.2 Recommendations for Future Work 1. It should be a very important aim of the next student to optimize the PSC design and eliminate the dead volume gap as best as possible, as this was demonstrated to have a large effect on timing: namely injection duration and mass flow control. Better con- trol of the timing and possible elimination of the dead volume could see more accu- rate data results of emissions based on the combustion. In terms of the CERC Ricar- do Hydra, this would involve the design of a new cylinder head to allow for increased space around the spark plug / PSC insert location so that the long injection tube length could be decreased as much as possible. It would also be possible to include an extra valve system that would clear the dead volume natural gas located between the check valve and the solenoid to atmosphere immediately after injection cessation, therefore preventing this gas from entering the combustion cylinder and being includ- ed in the emissions results. 2. Research should continue on finding more optimal natural gas injectors and their dri- vers. Results could become much more accurate with more accurate control of the in- jection mechanism. The model solenoid used herein, Omega SV122, offers poor re- action times and is possibly a source of increased tHC and CH4 emissions. One company, Vaporpro, has designed a prototype spark plug fuel injector (US Patent 6955154B1 and US Patent Pending 11/713,355) that may be worth investigating. Also, an injection control box could be designed to not only charge the coils of and open the injector, but also discharge the coils and therefore refine the controllability of reaction times. 3. More designs of injection patterns should be explored, perhaps integrating the con- cept of the swirl (B pattern) and the penetrative (C pattern). 83 4. A double injection pattern should be investigated, promoting the initial kernel forma- tion, and possibly supplying the combustion process with a fresh "dose" of natural gas.  Preliminaries for this idea were explored by Ed Chan (Chan 2010). 84 References Alger, Terry, Barrett Manglod, Darius Mehta, and Charles Roberts. April 2006. “The Effect of Sparkplug Design on Initial Flame Kernel Development and Sparkplug Performance.” Paper presented at the SAE 2006 World Congress, Detroit. Attar, A.A., and G.A. Karim. April 2003. “Knock Rating of Gaseous Fuels.” Eng. Gas Turbines Power Vol 125, no. 2 : 500-04. Brown, Greg. 2003. “Performance of a Partially Stratified-Charge Gasoline Engine.” MASc diss., University of British Columbia. Burgett, Richard R., Joseph M. Leptich, and Karma V. S. Sangwan. 1972. “Measuring the Effect of Spark Plug and Ignition System Design on Engine Performance.” SAE Technical Paper 720007. Chan, Edward. 2010. “Spark Ignition of Partially Stratified Gaseous Fuel-Air Mixtures.” PhD diss., University of British Columbia. Cheung, Hon M., and John B. Heywood. 1993. “Evaluation of a One-Zone Burn-Rate Analysis Procedure Using Production Si Engine Pressure Data.” SAE Technical Paper 932749. Cho, H.M., and B-Q He. 2007. “Spark Ignition Natural Gas Engines - a Review.” Energy Conversion and Management 48, no. 2 : 608-18. Craver, Robert J., Richard S. Podiak, and Reginald D. Miller. February 1970. “Spark Plug Design Factors and Their Effect on Engine Performance.” SAE Technical Paper 700081. Dauncey, Guy, and Patrick Mazza. 2001. Stormy Weather: 101 Solutions to Global Climate Change. Vancouver: New Society Publishers. Evans, R.L., and J. Blasczyk. 1998. “Fast-Burn Combustion Chamber Design for Natural Gas Engines.” ICE, Transactions of the ASME 120 : 232-36. Evans, R.L., and J. Blasczyk. 1994. “Comparison of Engine Performance and Emissions From Natural Gas and Gasoline Fuelled Spark Ignition Engines.” Transport Canada Publication TP 12145E. Frailey, M., P. Norton, N.N. Clark, and D.W. Lyons. October 2000. “An Evaluation of Natural Gas in Medium-Duty Buses.” Paper presented at the SAE International Fall Fuels and Lubricants Meeting and Exposition, Baltimore. 85 Gete, Zenebe. 1991. “Jet-Enchanced Turbulent Combustion.” MASc diss., University of British Columbia. Gorby, David. 2007. “An Evaluation of Partially Stratified Charge Ignition in a Direct Injection Natural Gas Engine.” MASc diss., University of British Columbia. Gorby, David. 2008. “PSC Design.” Labwork, University of British Columbia. Green, R.K., and C.C. Zavier. 1992. “Charge Stratification in a Spark Ignition Engine.” Proceedings of the Institution of Mechanical Engineers 206, Part A : 59-64. Heywood, John. 1988. Internal Combustion Engine Fundementals. Edited by Anne Duffy, and John M. Morris. New York: McGraw-Hill Book Company. Ingersoll, J. G. 1996. Natural Gas Vehicles. Georgia: The Fairmont Press. Malenshek, Martin, and Daniel B. Olsen. April 2009. “Methane Number Testing of Alternative Gaseous Fuels.” Fuel 88 : 650-56. Nakamura, H., T. Ohinouye, Kenji Hori, Yuhiko Kiyota, Tatsuro Nakagami, Katsuo Akishino, and Yutaka Tsukamoto. 1978. “Development of a New Combustion System (Mca-Jet) in Gasoline Engine.” SAE Technical Paper 780007. Rahmouni, C., Brecq G., M. Tazerout, and O. Le Corre. 2004. “Knock Rating of Gaseous Fuels in a Single Cylinder Spark Ignition Engine.” Fuel 83 : 327-36. Raine, R.R., G. Zhang, and A. Pflug. 1997. “Comparison of Emissions From Natural Gas and Gasoline Fuelled Engines - Total Hydrocarbon and Methane Emissions and Exhaust Recirculation Effects.” SAE 970743 : 41-49. Reynolds, Conor. 2001. “Performance of a Partially Stratified-Charge Natural Gas Engine.” MASc diss., University of British Columbia. Innovations, Westport. June, 2010. “Gas Composition Summary.” WMO, UNEP, and Environment Canada. June 27-30, 1988. Paper presented at the The Changing Atmosphere, Implications for Global Security, Toronto, Ontario. Yaws, Carl L., and William Braker. 2001. Matheson Gas Data Book. 7th Edition ed. New York: McGraw-Hill. Zhang, Dehong. 1995. “Turbulent Swirling Combustion of Premixed Natural Gas and Air.” PhD diss., University of British Columbia. 86 Appendix A: Drawings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ppendix B: Additional Graphs of Data Results !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"049":049";!(%<"4:":=/0"->"'(*"5-:5?" 7.8"3"451612-0"3"'"3"049":049";!(%<"4:":=/0"->"'(*"5-:5?" Figure 88: Original PSC, Coefficient of Variation, Low Flow, 2500rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$451612-0$3$#$ 7.8$3$451612-0$3$#$3$049$:049$;#+'<$4:$:=/0$->$*+%$5-:5?$ 7.8$3$451612-0$3$*$3$049$:049$;#+'<$4:$:=/0$->$*+%$5-:5?$ Figure 89: Original PSC, BSFC, Low Flow, 2500rpm 95 !"#$%& !'#(%& !'#$%& !)#(%& !)#$%& *(#(%& *(#$%& *+#(%& *+#$%& +#*& +#*$& +#,& +#,$& +#$& +#$$& +#-& +#-$& +#"& +#"$& !" #$ % & '( #) )* +* #, +- (./ 0( $&)$( ./012341&5&673834/2&5&(& 90:&5&673834/2&5&(&5&26;&<26;&=(#-%&6<&<>12&/?&+#$&7/<7@& 90:&5&673834/2&5&+&5&26;&<26;&=(#-%&6<&<>12&/?&+#$&7/<7@& Figure 90: Original PSC, Thermal Efficiency, Low Flow, 2500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" 5+6"0"12.3./*-"0"4"0"-17"8-17"94#&:"18"8;,-"*<"'#$"2*82=" 5+6"0"12.3./*-"0"'"0"-17"8-17"94#&:"18"8;,-"*<"'#$"2*82=" Figure 91: Original PSC, BMEP, Low Flow, 2500rpm 96 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"562723.1"4"'" 8/9"4"562723.1"4"'"4"15:";15:"<',)="5;";>01".?"#,+"6.;6@" 8/9"4"562723.1"4"#"4"15:";15:"<',)="5;";>01".?"#,+"6.;6@" Figure 92: Original PSC, tHC Emissions, Low Flow, 2500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"049":049";!(%<"4:":=/0"->"'(*"5-:5?" 7.8"3"451612-0"3"'"3"049":049";!(%<"4:":=/0"->"'(*"5-:5?" Figure 93: Original PSC, Methane Emissions, Low Flow, 2500rpm 97 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<)('="4:":>/0"-?"'(%*"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<)('="4:":>/0"-?"'(%*"5-:5@" Figure 94: Original PSC, Coefficient of Variation, High Flow, 1500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<#="4:":>/0"-?"'(%)"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<'(+="4:":>/0"-?"'(%)"5-:5@" Figure 95: Original PSC, Coefficient of Variation, High Flow, 2500rpm 98 !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$451612-0$3$#$ 7.8$3$451612-0$3$#$3$9169$:04;$<!=$4:$:>/0$-?$*+'"$5-:5@$ 7.8$3$451612-0$3$*$3$9169$:04;$<*+(=$4:$:>/0$-?$*+'"$5-:5@$ Figure 96: Original PSC, BSFC, High Flow, 2500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" 5+6"0"12.3./*-"0"4"0"7.37"8-19":!#';"18"8<,-"*="'#&$"2*82>" 5+6"0"12.3./*-"0"'"0"7.37"8-19":!#';"18"8<,-"*="'#&$"2*82>" Figure 97: Original PSC, BMEP, High Flow, 1500rpm 99 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"12.3./*-"0"4" 5+6"0"12.3./*-"0"4"0"7.37"8-19":;<"18"8=,-"*>"'#&!"2*82?" 5+6"0"12.3./*-"0"'"0"7.37"8-19":'#(<"18"8=,-"*>"'#&!"2*82?" Figure 98: Original PSC, BMEP, High Flow, 2500rpm !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"562723.1"4"'" 8/9"4"562723.1"4"'"4":27:";15<"=&>"5;";?01".@"#,)+"6.;6A" 8/9"4"562723.1"4"#"4":27:";15<"=&>"5;";?01".@"#,)+"6.;6A" Figure 99: Original PSC, Total Hydrocarbons, High Flow, 2000rpm 100 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"562723.1"4"'" 8/9"4"562723.1"4"'"4":27:";15<"=&>"5;";?01".@"#,)("6.;6A" 8/9"4"562723.1"4"#"4":27:";15<"=#,%>"5;";?01".@"#,)("6.;6A" Figure 100: Original PSC, Total Hydrocarbons, High Flow, 2500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<#="4:":>/0"-?"'(%*"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<#="4:":>/0"-?"'(%*"5-:5@" Figure 101: Original PSC, Methane, High Flow, 2000rpm 101 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"451612-0"3"!" 7.8"3"451612-0"3"!"3"9169":04;"<#="4:":>/0"-?"'(%)"5-:5@" 7.8"3"451612-0"3"'"3"9169":04;"<'(+="4:":>/0"-?"'(%)"5-:5@" Figure 102: Original PSC, Methane, High Flow, 2500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"074"8074"9!(&:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-'"3"074"8074"9!(&:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-)"3"074"8074"9!(&:"78"8;/0"-<"'(*"=-8=>" Figure 103: New PSC-A, Coefficient of Variation, Low FLow, 2000rpm 102 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"074"8074"9!(&:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",'"3"074"8074"9!(+*:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",)"3"074"8074"9!(+*:"78"8;/0"-<"'(*"=-8=>" Figure 104: New PSC-B, Coefficient of Variation, Low Flow, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"074"8074"9!(+*:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-'"3"074"8074"9!(+:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3"-)"3"074"8074"9!(%:"78"8;/0"-<"'(*"=-8=>" Figure 105: New PSC-A, Coefficient of Variation, Low Flow, 2500rpm 103 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"074"8074"9!(%:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",'"3"074"8074"9!(%:"78"8;/0"-<"'(*"=-8=>" 5.6"3"2/4"3",)"3"074"8074"9!(%:"78"8;/0"-<"'(*"=-8=>" Figure 106: New PSC-B, Coefficient of Variation, Low Flow, 2500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"-51"6-51"7'8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0"*'"0"-51"6-51"7'8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0"*!"0"-51"6-51"7'8"56"69,-"*:"'#$";*6;<" Figure 107: New PSC-A, BMEP, Low Flow, 1500rpm 104 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"-51"6-51"72#($8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0"*'"0"-51"6-51"72#(8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0"*!"0"-51"6-51"72#&8"56"69,-"*:"'#$";*6;<" Figure 108: New PSC-A, BMEP, Low Flow, 2500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0")2"0"-51"6-51"72#&8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0")'"0"-51"6-51"72#&8"56"69,-"*:"'#$";*6;<" 3+4"0"/,1"0")!"0"-51"6-51"72#&8"56"69,-"*:"'#$";*6;<" Figure 109: New PSC-B, BMEP, Low Flow, 2500rpm 105 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"185"9185":',%+;"89"9<01".="#,+">.9>?" 6/7"4"305"4"-#"4"185"9185":#;"89"9<01".="#,+">.9>?" 6/7"4"305"4"-("4"185"9185":#;"89"9<01".="#,+">.9>?" Figure 110: New PSC-B, Total Hydrocarbons, Low Flow, 1500rpm !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"185"9185":',!;"89"9<01".="#,+">.9>?" 6/7"4"305"4"-#"4"185"9185":',%+;"89"9<01".="#,+">.9>?" 6/7"4"305"4"-("4"185"9185":',%+;"89"9<01".="#,+">.9>?" Figure 111: New PSC-B, Total Hydrocarbons, Low Flow, 2000rpm 106 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";)(*<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";)(*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";#(#*<":9"9=/0"->"'(%*"?-9?@" Figure 112: New PSC-A, Coefficient of Variation, High Flow, 1500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";$<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";)()<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";#(#*<":9"9=/0"->"'(%*"?-9?@" Figure 113: New PSC-B, Coefficient of Variation, High Flow, 1500rpm 107 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()!" '()*" '($!" '($*" '(*!" '(**" '(%!" '(%*" '(+!" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";'()<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";'('*<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";'<":9"9=/0"->"'($*"?-9?@" Figure 114: New PSC-A, Coefficient of Variation, High Flow, 2500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()!" '()*" '($!" '($*" '(*!" '(**" '(%!" '(%*" '(+!" '(+*" !" # $%& '( $)* +$ ,-.,$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";'(#<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";'(#<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";'<":9"9=/0"->"'(**"?-9?@" Figure 115: New PSC-B, Coefficient of Variation, High Flow, 2500rpm 108 !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$7187$90:4$;"+%<$:9$9=/0$->$*+'$?-9?@$ 5.6$3$2/4$3$-*$3$7187$90:4$;"+%<$:9$9=/0$->$*+'%$?-9?@$ 5.6$3$2/4$3$-"$3$7187$90:4$;!+!%<$:9$9=/0$->$*+'%$?-9?@$ Figure 116: New PSC-A, BSFC, High Flow, 1500rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$,#$3$7187$90:4$;&<$:9$9=/0$->$*+'%$?-9?@$ 5.6$3$2/4$3$,*$3$7187$90:4$;"+"<$:9$9=/0$->$*+'%$?-9?@$ 5.6$3$2/4$3$,"$3$7187$90:4$;!+!%<$:9$9=/0$->$*+'%$?-9?@$ Figure 117: New PSC-B, BSFC, High Flow, 1500rpm 109 !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$-#$3$7187$90:4$;*+"<$:9$9=/0$->$*+'$?-9?@$ 5.6$3$2/4$3$-*$3$7187$90:4$;*+*%<$:9$9=/0$->$*+%%$?-9?@$ 5.6$3$2/4$3$-"$3$7187$90:4$;*<$:9$9=/0$->$*+&%$?-9?@$ Figure 118: New PSC-A, BSFC, High Flow, 2500rpm !"#$ !"%$ !&#$ !&%$ !%#$ !%%$ !'#$ !'%$ !(#$ !(%$ !)#$ !)%$ *+"$ *+"%$ *+&$ *+&%$ *+%$ *+%%$ *+'$ *+'%$ *+($ *+(%$ !" #$ %&' () * +, -. % /0#/% ,-./012/$3$2/4$3$#$ 5.6$3$2/4$3$,#$3$7187$90:4$;*+!<$:9$9=/0$->$*+%%$?-9?@$ 5.6$3$2/4$3$,*$3$7187$90:4$;*+!<$:9$9=/0$->$*+%%$?-9?@$ 5.6$3$2/4$3$,"$3$7187$90:4$;*<$:9$9=/0$->$*+%%$?-9?@$ Figure 119: New PSC-B, BSFC, High Flow, 2500rpm 110 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"5.65"7-81"9!#$:"87"7;,-"*<"'#&"=*7=>" 3+4"0"/,1"0"*'"0"5.65"7-81"9!#$:"87"7;,-"*<"'#&$"=*7=>" 3+4"0"/,1"0"*!"0"5.65"7-81"9?#?$:"87"7;,-"*<"'#&$"=*7=>" Figure 120: New PSC-A, BMEP, High Flow, 1500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0")2"0"5.65"7-81"9%:"87"7;,-"*<"'#&$"=*7=>" 3+4"0"/,1"0")'"0"5.65"7-81"9!#!:"87"7;,-"*<"'#&$"=*7=>" 3+4"0"/,1"0")!"0"5.65"7-81"9?#?$:"87"7;,-"*<"'#&$"=*7=>" Figure 121: New PSC-B, BMEP, High Flow, 1500rpm 111 !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0"*2"0"5.65"7-81"9'#!:"87"7;,-"*<"'#&"=*7=>" 3+4"0"/,1"0"*'"0"5.65"7-81"9'#'$:"87"7;,-"*<"'#$$"=*7=>" 3+4"0"/,1"0"*!"0"5.65"7-81"9':"87"7;,-"*<"'#%$"=*7=>" Figure 122: New PSC-A, BMEP, High Flow, 2500rpm !" !#$" %" %#$" $" $#$" &" &#$" '#!" '#!$" '#%" '#%$" '#$" '#$$" '#&" '#&$" '#(" '#($" !" #$ %&! '( )% *+,*% )*+,-./,"0"/,1"0"2" 3+4"0"/,1"0")2"0"5.65"7-81"9'#:;"87"7<,-"*="'#$$">*7>?" 3+4"0"/,1"0")'"0"5.65"7-81"9'#:;"87"7<,-"*="'#$$">*7>?" 3+4"0"/,1"0")!"0"5.65"7-81"9';"87"7<,-"*="'#$$">*7>?" Figure 123: New PSC-B, BMEP, High Flow, 2500rpm 112 !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4".!"4"8298":1;5"<%,'=";:":>01".?"#,("@.:@A" 6/7"4"305"4".#"4"8298":1;5"<%,'=";:":>01".?"#,('"@.:@A" 6/7"4"305"4".%"4"8298":1;5"<$,$'=";:":>01".?"#,('"@.:@A" Figure 124: New PSC-A, Nitrous Oxide, High Flow, 1500rpm !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4"-!"4"8298":1;5"<&=";:":>01".?"#,('"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<%,%=";:":>01".?"#,('"@.:@A" 6/7"4"305"4"-%"4"8298":1;5"<$,$'=";:":>01".?"#,('"@.:@A" Figure 125: New PSC-B, Nitrous Oxide, High Flow, 1500rpm 113 !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4".!"4"8298":1;5"<#,%=";:":>01".?"#,("@.:@A" 6/7"4"305"4".#"4"8298":1;5"<#,#'=";:":>01".?"#,''"@.:@A" 6/7"4"305"4".%"4"8298":1;5"<#=";:":>01".?"#,&'"@.:@A" Figure 126: New PSC-A, Nitrous Oxide, High Flow, 2500rpm !" #" $" %" &" '" (" )" *" +" #!" #,%" #,%'" #,&" #,&'" #,'" #,''" #,(" #,('" #,)" #,)'" ! " #$ %& '( ) *+ ,- $ ./0.$ -./01230"4"305"4"!" 6/7"4"305"4"-!"4"8298":1;5"<#,$=";:":>01".?"#,''"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<#,$=";:":>01".?"#,''"@.:@A" 6/7"4"305"4"-%"4"8298":1;5"<#=";:":>01".?"#,''"@.:@A" Figure 127: New PSC-B, Nitrous Oxide, High Flow, 2500rpm 114 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4".'"4"8298":1;5"<(,+=";:":>01".?"#,)"@.:@A" 6/7"4"305"4".#"4"8298":1;5"<(,+=";:":>01".?"#,)+"@.:@A" 6/7"4"305"4".("4"8298":1;5"<&,&+=";:":>01".?"#,)+"@.:@A" Figure 128: New PSC-A, Total Hydrocarbons, High Flow, 1500rpm !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"8298":1;5"<$=";:":>01".?"#,)+"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<(,(=";:":>01".?"#,)+"@.:@A" 6/7"4"305"4"-("4"8298":1;5"<&,&+=";:":>01".?"#,)+"@.:@A" Figure 129: New PSC-B, Total Hydrocarbons, High Flow, 1500rpm 115 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4".'"4"8298":1;5"<#,%=";:":>01".?"#,)"@.:@A" 6/7"4"305"4".#"4"8298":1;5"<#,%+=";:":>01".?"#,)"@.:@A" 6/7"4"305"4".("4"8298":1;5"<#,)=";:":>01".?"#,)"@.:@A" Figure 130: New PSC-A, Total Hydrocarbons, High Flow, 2000rpm !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"8298":1;5"<&,%+=";:":>01".?"#,)+"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<#,%+=";:":>01".?"#,)+"@.:@A" 6/7"4"305"4"-("4"8298":1;5"<#,%+=";:":>01".?"#,++"@.:@A" Figure 131: New PSC-B, Total Hydrocarbons, High Flow, 2000rpm 116 !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,('" #,(+" #,$'" #,$+" #,+'" #,++" #,)'" #,)+" #,%'" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4".'"4"8298":1;5"<#,(=";:":>01".?"#,)"@.:@A" 6/7"4"305"4".#"4"8298":1;5"<#,#+=";:":>01".?"#,++"@.:@A" 6/7"4"305"4".("4"8298":1;5"<#=";:":>01".?"#,$+"@.:@A" Figure 132: New PSC-A, Total Hydrocarbons, High Flow, 2500rpm !" ##" #$" #%" &'" &(" &)" &*" (&" (+" #,(" #,(+" #,$" #,$+" #,+" #,++" #,)" #,)+" #,%" #,%+" !" #$ %& '( )* + ,- ./ & 0120& -./01230"4"305"4"'" 6/7"4"305"4"-'"4"8298":1;5"<#,&=";:":>01".?"#,++"@.:@A" 6/7"4"305"4"-#"4"8298":1;5"<#,&=";:":>01".?"#,++"@.:@A" 6/7"4"305"4"-("4"8298":1;5"<#=";:":>01".?"#,++"@.:@A" Figure 133: New PSC-B, Total Hydrocarbons, High Flow, 2500rpm 117 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";)(*<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";)(*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";#(#*<":9"9=/0"->"'(%*"?-9?@" Figure 134: New PSC-A, Methane, High Flow, 1500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";$<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";)()<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";#(#*<":9"9=/0"->"'(%*"?-9?@" Figure 135: New PSC-B, Methane, High Flow, 1500rpm 118 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";'(+<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";'(+*<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";'(%<":9"9=/0"->"'(%"?-9?@" Figure 136: New PSC-A, Methane, High Flow, 2000rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";#(+*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";'(+*<":9"9=/0"->"'(%*"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";'(+*<":9"9=/0"->"'(**"?-9?@" Figure 137: New PSC-B, Methane, High Flow, 2000rpm 119 !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()!" '()*" '($!" '($*" '(*!" '(**" '(%!" '(%*" '(+!" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3"-!"3"7187"90:4";'()<":9"9=/0"->"'(%"?-9?@" 5.6"3"2/4"3"-'"3"7187"90:4";'('*<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3"-)"3"7187"90:4";'<":9"9=/0"->"'($*"?-9?@" Figure 138: New PSC-A, Methane Emissions, High Flow, 2500rpm !" #" $" %" &" '!" '#" '$" '%" '&" #!" '()" '()*" '($" '($*" '(*" '(**" '(%" '(%*" '(+" '(+*" !" #$ %& '( ) *+ ,- $ ./0.$ ,-./012/"3"2/4"3"!" 5.6"3"2/4"3",!"3"7187"90:4";'(#<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3",'"3"7187"90:4";'(#<":9"9=/0"->"'(**"?-9?@" 5.6"3"2/4"3",)"3"7187"90:4";'<":9"9=/0"->"'(**"?-9?@" Figure 139: New PSC-B, Methane, High Flow, 2500rpm 120 Appendix C: Engine Operating Procedures Ricardo Hydra Engine (NG) Operating Procedure Alternative Fuels Laboratory, UBC Mechanical Engineering The following is the start-up procedure for the Ricardo Hydro single-cylinder research engine in the UBC Alternative Fuels Laboratory. Please follow these steps carefully to avoid equipment damage or injury to personnel. Note: Steps preceded by the DI superscript are particular to the Natural Gas Direct Injection System. If the injector is not installed these steps are omitted. If the DI injector is installed, these steps must be followed regardless of whether or not DI will be used in current trials. Initial checks and engine warm-up: 1. Turn on ventilation in test cell (main fan - switch outside door - and fume hood). 2. Turn on emissions bench to allow sufficient warm-up (see separate procedure). 3. Check engine oil and coolant levels, and check around the engine for leaks. 4. Check that guards are on flywheel and timing belt. 5. Crank engine by hand once or twice (to ensure there has been no leak into the combustion chamber). 6. Check that there is no condensation in the exhaust (briefly open valves: engine out, muffler drain and horizontal run). Ensure all drains are closed before engine start. 7. Turn on engine cooling water (open tap fully). 8. Start pressure transducer cooling pump. 9. Turn on ignition/injection driver box (test-cell – by DAQ). 10. If the natural gas direct injector will be used, plug in the power supply first, then plug injector driver into power supply. (Not mandatory if injector will not be used) 11. Turn on thyristor drive unit in the test cell. (Main breaker on cell wall should be left on). 12. Turn on oil and water pumps/heaters. 13. Ensure that back pressure valve control box is powered and that valve is plugged in. 14. While oil and water are heating, calibrate emissions bench (see separate procedure). Starting the engine software: 15. Turn on the control room computer (password = “Ricardo”). 16. Open Dynoclient and select file to save data to (in D:\ drive). The file name should have 121 the following format: <date>_<user>_<speed>_<throttle%>_<test description>.csv, for example: “031121_CR_2000rpm_100%_homogeneous_lean_limit_noPSC.csv”. (Note: If not acquiring data, open “junkdynodata.csv”.) 17. Open Pressureclient. 18. Open VNC, (password = “Riccardo”). Run Timing Controller. 19. Open/run Ric_Emissions_Runtime for monitoring calculated values. (Start Menu, “Programs”, “Windows NT Explorer”, D:\…) Starting the Engine: 20. Reset emergency stop buttons (one on post by engine, one on control panel). 21. Open the two green NG valves in test cell, and the NG valve in the control room. 22. DI Turn on high-pressure supply at the test cell outer wall gas panel, and ensure that the supply pressure is between 2000 and 3000 psi - do not operate this panel without prior instruction. 23. DI Ensure that in-cell high-pressure supply valve is fully open, and vent valve on test cell outer wall is fully closed. 24. Turn on ignition switch (control panel). 25. Check oil temperature is greater than 60 °C 26. Check (control panel): • Speed setting is at 3.0 (1500 rpm) • Throttle setting is at 50% • Fuel setting is at 2.2 27. Make a note of the following in the Ricardo Logbook: • Date • Engine hours • Speed and Load • Operator Comment (test description) and initials 28. Press “reset” then immediately press green “start” button. (DI listen for pneumatic highpressure supply cut-off valve to energize upon pressing “reset”. Do not proceed if valve does not energize.) Firing the Engine: (Engine firing is always started at 1500rpm, 50% Throttle, Lambda 1.0 and MBT Spark) 29. In Timing Controller set spark timing to –23 deg, (“duration” should be set to 1.0 deg). Turn on ignition. 30. Check fuel control is set to “flow” (switch 1) then turn on (switch 2). Engine should fire. (Note that fuel flow output on DAQ should be 0.8 kg/h – this corresponds to lambda 1.0). 31. After one minute of firing, turn on AFRecorder (lambda sensor): • Press “sys”, “6” (says ‘enable’), “ENT”, “1” (says ‘measure’). 32. Wait until oil temperature is approx. 90 °C and coolant temperature is approx 95 °C 122 before beginning to acquire data. Important Note: If testing for a long time, may need to recalibrate the emissions bench, as the calibration of the instruments drifts with changing temperature. Recommended Practice: Before proceeding with the test, run the engine at the above “standard” conditions for at least 20 mins, and acquire data at this point (for repeatability). The emissions bench can be calibrated during this time. Acquiring Data: 33. Set test point. Note that when running very lean, the lambda based on mass flows is more accurate than lambda from the AFRecorder, (i.e. use Ric_Emissions_Runtime by pressing “Send data to Excel” button in Dynoclient). 34. In the paper “Test Sheet”, record details of test point for future reference. 35. Record Pressure data (must be done for every test point). The file name should have the following format: <date>_<test#>_<speed>_<throttle%>_<spark>_<Lambda>_<PSCdetails>_pr.csv, for example: “031121_t05_2000rpm_50%_S23 _L1.0_noPSC_pr.csv”. 36. Record Performance data: In Dynoclient, update: • Test number • Spark timing • PSC details (if running with PSC) Then click “Log data to File” and wait (approx. 2 mins.) 37. Set next test point and repeat data acquisition. 38. When testing is finished, return the engine to the start-up settings (1500rpm, 50% throttle, lambda 1.0). Shutting down the engine: 39. Turn off the NG supply at the flow-meter. 40. Turn off ignition (Timing Controller on computer. 41. Allow engine to motor briefly, until exhaust temperature drops below 130oC. 42. Press red “dyno” stop button. Engine will come to a complete stop. 43. Turn off ignition switch on control panel 44. Turn off oil/water heaters (but not the pumps). 45. About two minutes after firing stops, disable AFRecorder. • Press “sys”, “6” (says ‘enable’), “ENT”, “1” (says ‘measure’). • Display should now read ‘Sensor Disabled’ 46. Close all three NG valves on NG lines. 47. DI Turn off high-pressure supply at the test cell outer wall gas panel. 48. Turn off switch on ignition/injection box in test cell. 49. If plugged in, unplug natural gas direct injector power supply and driver box (order doesn’t matter). 50.When engine has cooled (after at least fifteen minutes): • Turn off oil and water pumps. 123 • Turn off the thyristor drive breaker. • Turn off cooling water tap and unplug pressure transducer cooling pump • Shut down emissions bench. • Stop all software and shut down control room computer. 51. When testing is complete and engine shut down, stop the Dynoclient – this closes the file you have been saving performance data to. (if you wish to continue monitoring engine conditions during the cool-down stage, start Dynoclient again and use “junkdynodata.csv”). 52. Comment on any important issues in the Ricardo Logbook, record engine hours and running time. 124

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