CONTENTS ACKNOWLEDGEMENTS ...................................................................................................... x ACRONYMS AND ABBREVIATIONS ................................................................................. xi ABSTRACT .............................................................................................................................. 1 1 INTRODUCTION .............................................................................................................. 3 2 COVERAGE AND CHARACTERISTICS OF HEAVY-DUTY VEHICLE TYPES ....... 5 2.1 Conventional Heavy-Duty Vehicles .......................................................................... 5 2.1.1 Combination Long-Haul Trucks ..................................................................... 9 2.1.2 Combination Short-Haul Trucks .................................................................... 10 2.1.3 Refuse Trucks ................................................................................................. 11 2.1.4 Vocational Vehicles ........................................................................................ 11 2.1.5 Heavy-Duty Pickup Trucks and Vans ............................................................ 14 2.1.6 Transit Buses .................................................................................................. 14 2.1.7 Intercity Buses ................................................................................................ 15 2.1.8 School Buses .................................................................................................. 16 2.2 Alternative Fuel Heavy-Duty Vehicles ...................................................................... 16 2.2.1 Biodiesel ......................................................................................................... 17 2.2.2 Natural Gas ..................................................................................................... 17 2.2.3 Liquefied Petroleum Gas ................................................................................ 19 2.2.4 Hybrid Vehicles .............................................................................................. 19 2.2.5 Battery Electric Vehicles ................................................................................ 19 2.2.6 Ethanol ............................................................................................................ 20 2.2.7 Dimethyl Ether ............................................................................................... 20 2.2.8 Other Alternative-Fuel Vehicles ..................................................................... 20 3 FUEL CONSUMPTION AND EMISSIONS OF CONVENTIONAL DIESEL AND GASOLINE VEHICLES .................................................................................................... 25 3.1 Conventional Diesel and Gasoline Trucks and Vocational Vehicles ........................ 25 3.1.1 Fuel Consumption .......................................................................................... 25 3.1.2 Emissions ........................................................................................................ 32 3.2 Conventional Diesel Buses ........................................................................................ 45 3.2.1 Fuel consumption ........................................................................................... 45 3.2.2 Emissions ........................................................................................................ 46 4 FUEL CONSUMPTION AND EMISSIONS OF ALTERNATIVE-FUEL VEHICLES ......................................................................................................................... 49 4.1 Biodiesel .................................................................................................................... 49 4.1.1 Fuel Economy ................................................................................................. 49 iii CONTENTS (CONT.) 4.1.2 Emissions ........................................................................................................ 50 4.2 Compressed Natural Gas............................................................................................ 55 4.2.1 Fuel Economy ................................................................................................. 55 4.2.2 Emissions ........................................................................................................ 58 4.3 Liquefied Natural Gas ................................................................................................ 67 4.4 Liquefied Petroleum Gas ........................................................................................... 70 4.5 Hybrid Electric Vehicles ............................................................................................ 72 4.6 Hydraulic Hybrid Vehicles ........................................................................................ 77 4.7 Battery Electric Vehicles ........................................................................................... 79 4.8 Ethanol ....................................................................................................................... 79 4.9 Dimethyl Ether ........................................................................................................... 80 5 PROJECTION OF FUEL ECONOMY BY HDV SUBCATEGORY ............................... 83 6 DISCUSSION AND OUTSTANDING ISSUES ............................................................... 87 6.1 Fuel Consumption ...................................................................................................... 87 6.2 Air Pollutant Emissions ............................................................................................. 88 6.3 Alternative Fuel and Advanced Vehicles .................................................................. 89 7 REFERENCES ................................................................................................................... 92 APPENDIX A: CO2 EMISSIONS AND FUEL CONSUMPTION STANDARD FOR HEAVY-DUTY VEHICLES ......................................................................... 108 APPENDIX B: ANALYSIS OF 2002 VEHICLE INVENTORY AND USE SURVEY ........ 112 APPENDIX C: VIUS-BASED VEHICLE OPERATIONAL CHARACTERISTICS ............. 116 APPENDIX D: DRIVING CYCLES OF HEAVY-DUTY VEHICLES .................................. 132 FIGURES 1 Combination long-haul truck ........................................................................................... 9 2 Combination short-haul truck .......................................................................................... 10 3 Refuse truck ..................................................................................................................... 11 4 Heavy heavy-duty vocational vehicle – Class 8 dump truck ........................................... 12 iv FIGURES (CONT.) 5 Medium heavy-duty vocational vehicle – Class 6 delivery truck .................................... 13 6 Light heavy-duty vocational vehicle – Class 4 delivery truck......................................... 13 7 Heavy-duty pickup truck ................................................................................................. 14 8 Transit bus........................................................................................................................ 15 9 Intercity bus ..................................................................................................................... 15 10 School bus ........................................................................................................................ 16 11 HDPI fuel system on LNG trucks .................................................................................... 18 12 Recent trends in fuel economy of combination trucks and single-unit trucks ................. 30 13 EPA PM and NOx emission standards for heavy-duty engines, 1988–2010 ................... 35 14 EPA HDV emission standards, 1988–2010 ..................................................................... 36 A1 EPA CO2 target standards and NHTSA fuel consumption target standards for diesel heavy-duty pickups and vans................................................................................. 109 D1 Heavy Duty Urban Dynamometer Driving Schedule Drive Cycle.................................. 132 D2 Braunschweig Drive Cycle .............................................................................................. 133 D3 ADEME Drive Cycle ....................................................................................................... 133 D4 Orange County Transit Authority Drive Cycle................................................................ 134 D5 Central Business District Drive Cycle ............................................................................. 134 D6 SCAQMD Refuse Truck Cycle ....................................................................................... 135 D7 City-Suburban Heavy-Vehicle Cycle .............................................................................. 135 D8 Combined International Local and Commuter Cycle ...................................................... 136 D9 Rowan University Composite School Bus Cycle ............................................................ 136 D10 The Freeway Cycle .......................................................................................................... 137 v FIGURES (CONT.) D11 Mumbai Drive