List of Figures and Tables xiii
The Journey Begins xxxiii
About the Author xxxv
Acknowledgments xxxvii
Abbreviations xxxix
About the Companion Website xlvii
1 Hydrogen: A Promising Frontier for Energy-Environment Solutions 1
1.1 Introduction 1
1.2 Fossil Fuel Combustion: Energy Security and Environmental Impact 1
1.3 Alternative Fuels for Internal Combustion (IC) Engines 2
1.4 Pollution from Vehicles 3
1.5 Hydrogen Energy Pathways 6
1.6 Hydrogen in a Net Zero Emission (NZE) Scenario 7
1.7 Hydrogen Color Codes and Carbon Footprint 7
1.8 Green Hydrogen 9
1.9 Electrolysis Development: Energy Demand and Global Warming Potential 11
1.10 Emission Through Hydrogen Production by Different Routes 12
1.11 Exhaust Emissions from Hydrogen Combustion in Engines 13
Concluding Remarks and Perspectives 13
References 14
2 Hydrogenâs Properties and Fuel Induction in Engines 17
2.1 Introduction 17
2.2 Physical Properties 17
2.2.1 Density, Diffusivity, and Expansion Ratio 18
2.2.2 Joule-Thomson Effect 21
2.3 Combustive Properties of Hydrogen 21
2.3.1 Reactivity, Energy, and Energy Density 22
2.3.2 Higher Heating Value (HHV) and Lower Heating Value (LHV) 23
2.3.3 Flammability Limit 24
2.3.4 Flash Point 26
2.3.5 Minimum Ignition Energy (MIE) 26
2.3.6 Autoignition Temperature 27
2.3.7 Maximum Experimental Safe Gap (MESG) and Quenching Gap 27
2.3.8 Octane Number 28
2.3.9 Stoichiometric Composition 28
2.3.10 Flame Speed 29
2.3.11 Adiabatic Flame Temperature 31
2.4 Emissivity of the Hydrogen Flame 31
2.5 Hydrogen Embrittlement 32
2.6 Green Hydrogen and Hydrogen Use in Engines 32
2.7 Combustion Strategy 33
Concluding Remarks and Perspectives 35
References 36
3 The Hydrogen Engine: Performance, Emission, and Combustion 39
3.1 Introduction 39
3.2 Hydrogen Engines: A Historical Journey of Nearly Two Centuries 39
3.3 Mixture Formation and Fuel Induction Techniques 41
3.4 Port Fuel Injection: Performance, Combustion, and Emission Features 44
3.5 Timed Manifold Injection: Injector Development 50
3.5.1 Performance Characteristics 52
3.5.2 NOx Control: Lean Mixture, Exhaust as Recirculation 52
3.5.3 Exhaust Gas Recirculation for NOx Control 56
3.5.4 NOx Control Techniques at High Equivalence Ratio 59
3.5.5 Combustion Characteristics 61
3.6 Direct Injection 63
3.6.1 Injector for HPDI Operation 64
3.6.2 Spark-Activated Direct Injection 66
3.6.3 Injection Strategies: Energy Proportion, Exergy Efficiency 67
3.6.4 Glow Plugâ"Assisted Direct Injection 71
3.7 Hydrogen as a Fuel for the Compression Ignition Engine 72
3.7.1 Hydrogenâ"Diesel Dual Fuel Engine 73
3.8 Optimization of Dual Fuel Operation 84
3.8.1 Injection Timing 84
3.8.2 Exhaust Gas Recirculation 86
3.8.3 Effects of Compression Ratio 86
3.8.4 Water Induction for Knock Control 87
3.8.5 Charge Dilution 88
3.9 Liquid Hydrogen 89
Concluding Remarks and Perspectives 93
References 95
4 Undesirable Combustion Phenomena 109
4.1 Introduction 109
4.2 Hydrogenâ"Oxygen Reaction Mechanism 109
4.3 Flammability Range and Explosion Limit 111
4.4 Flame Propagation 113
4.5 Laminar Burning Velocity 114
4.6 Preferential Diffusion and Turbulent Burning Velocity 121
4.7 Undesirable Combustion Phenomena in a Hydrogen Engine 123
4.7.1 Preignition 124
4.7.2 Knock Fundamentals: Autoignition, Octane Rating, Methane Number 126
4.7.3 Parameters That Influence Knock 127
4.8 Backfire: Causes and Character 143
4.8.1 Comprehensive Monitoring of Backfire 144
4.8.2 Optimized Valve Timing: Effect on Backfire 145
4.8.3 Injection Strategy 148
4.8.4 Equivalence Ratio 153
4.8.5 Compression Ratio 154
4.8.6 Slow Combustion of Mixture, Cold Start Condition 154
4.8.7 Exergy Analysis 157
4.8.8 Misfire 158
4.8.9 High Coolant and Lubricating Oil Temperature 160
4.8.10 Abnormal Discharge of Spark Plugs 161
4.8.11 Injection System: Timing, Pressure, and Duration 162
Concluding Remarks and Perspectives 167
References 167
5 Modeling and Simulation Studies on the Hydrogen Engine 175
5.1 Introduction 175
5.2 Chemical Kinetics Models 177
5.3 Thermodynamic Models 182
5.4 Computational Fluid Dynamics (CFD) Models 195
5.4.1 Turbulent Flame Speed Closure (TFC) Models 196
5.5 Heat Transfer Submodel 209
Concluding Remarks and Perspectives 221
References 221
6 Laser Diagnostics, Optical, and Other Sensing Techniques 227
6.1 Introduction 227
6.2 Key Laser Diagnostics and Optical Methods 227
6.3 Mixture Formation in a Hydrogen Engine 229
6.4 Laser-Induced Fluorescence (LIF), Planar Laser-Induced Fluorescence (PLIF), and Particle Image Velocimetry (PIV) 229
6.4.1 Planar Laser-Induced Fluorescence (PLIF) 229
6.4.2 Laser-Induced Fluorescence (LIF) 232
6.5 Particle Image Velocimetry 238
6.6 Laser-Induced Breakdown Spectroscopy (LIBS) 240
6.7 Spark-Induced Breakdown Spectroscopy (SIBS) 242
6.8 Plume Ignition Combustion Concept (PCC) 246
6.9 High-Speed Schlieren Imaging 246
6.10 Controlled Autoignition (Homogeneous Charge Compression Ignition) 247
Concluding Remarks and Perspectives 249
References 250
7 Design Criteria and Safety Features of a Dedicated Hydrogen Engine 253
7.1 Introduction 253
7.2 Safety-Related Properties for the Hydrogen Engine 254
7.3 Technical Features for Hydrogen Engine Design 255
7.4 Some Property-Based Benefits and Challenges 256
7.4.1 High Flame Speed 256
7.4.2 Quenching Distance 256
7.4.3 Diffusivity and Throttling 257
7.4.4 Hydrogen Leaks 257
7.4.5 Octane Number and Knock 257
7.5 NOx Emission 258
7.6 Load Control Strategy and Engine Components 258
7.6.1 Spark Plug 258
7.6.2 Ignition System 259
7.7 Emerging Ignition Technologies 259
7.8 Fuel Delivery System 261
7.9 Valves 264
7.10 Crankcase Ventilation 264
7.11 Hot Spots 265
7.12 Lubrication System 265
7.13 Piston Rings and Crevice Volumes 266
7.14 Combustion Chamber 266
7.15 Throttle, Compression Ratio 268
7.16 Materials 268
7.17 Rotary Engine Structure for Hydrogen Operation 270
7.18 Safety Features for Engine Tests in the Laboratory 270
7.19 Safety Considerations for H 2 IC Vehicles 271
Concluding Remarks and Perspectives 273
References 274
8 Hydrogen in Blends with Other Fuels 279
8.1 Introduction 279
8.2 Adding Hydrogen to CNG 279
8.2.1 Significant Research Results on Combustion, Emission, and Performance 281
8.2.2 Exhaust Gas Recirculation 291
8.2.3 Injection 295
8.2.4 Performance and Emission Characteristics During Long-Term Endurance Tests 299
8.3 Oil Analysis 300
8.3.1 Total Base Number (TBN) 301
8.3.2 Total Acid Number (TAN) 302
8.3.3 Spectrochemical Analysis for Wear Metals 302
8.3.4 Nitration 303
8.3.5 Deposits on Cylinder Head and Piston 303
8.4 Hydrogen Added to Biogas, Biodiesel 305
8.5 Hydrogenâ"Ethanol Blend 318
8.6 Hydrogenâ"DME 320
8.7 Hydrogen with LPG (Liquefied Petroleum Gas) and Propane 327
Concluding Remarks and Perspectives 340
References 342
9 Some Upgraded Strategies for Hydrogen Engines 349
9.1 Introduction 349
9.2 Supercharging and Turbocharging 349
9.2.1 Performance Features 351
9.2.2 Combustion Characteristics: Peak Pressure, Pressure Rise Rate, Heat Release Rate, Combustion Duration, Preignition, and Knock 353
9.3 Stratification and Injection Strategy 359
9.4 Homogeneous Charge Compression Ignition (HCCI) 368
9.4.1 Significant Features of HCCI Combustion 369
9.4.2 Modeling and Simulation Studies 371
9.4.3 Exhaust Emission in a HCCI Hydrogen Engine 373
9.5 Reactivity Controlled Compression Ignition (RCCI) 374
9.6 Hydrogen Rotary Engine 375
9.6.1 Leakage Issues in the Hydrogen Rotary Engine 379
Concluding Remarks and Perspectives 380
References 381
10 The Path Forward 389
10.1 Introduction 389
10.2 Hydrogen Engines for Land and Marine Transport 389
10.3 Heavy-Duty Engines, Trucks, and Generating Sets 393
10.4 The Rotary Engine 397
Concluding Remarks 398
References 398
Index 401
