Hybrid-Electric Vehicle Design and Applications Eric Adams
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Rochester Institute of Technology RIT Scholar Works Theses Thesis/Dissertation Collections 1995 Hybrid-electric vehicle design and applications Eric Adams Follow this and additional works at: http://scholarworks.rit.edu/theses Recommended Citation Adams, Eric, "Hybrid-electric vehicle design and applications" (1995). Thesis. Rochester Institute of Technology. Accessed from This Thesis is brought to you for free and open access by the Thesis/Dissertation Collections at RIT Scholar Works. It has been accepted for inclusion in Theses by an authorized administrator of RIT Scholar Works. For more information, please contact [email protected]. Hybrid-Electric Vehicle Design and Applications by Eric E. Adams A Thesis Submitted in Partial Fulfillment of the Requirements for the Master of Science in Mechanical Engineering Approved by: Professor Alan Nige Thesis Advisor Professor _ Professor _ Professor _ Department Head Department of Mechanical Engineering College of Engineering Rochester Institute of Technology December 1995 I, Eric Adams, hereby grant permission to the Wallace Memorial Library of the Rochester Institute. of Technology in Rochester, NY, to reproduce my thesis entitled, Hybrid Electric Vehicle Design and Applications, in whole or in part. Any and all reproductions will not be for commercial use or profit. Eric E. Adams Abstract: This paper discusses the considerations involved in hybrid-electric vehicle design. The tradeoffs between issues such as drive scheme/arrangement, motor choice, batteries, and temperature control are investigated. The technologies and components which are currently available, and those which are likely in the near future, are described. A sport utility vehicle is taken as a specific case study because they are very popular and relatively inefficient. Calculations indicate that a hybrid sport utility vehicle with all wheel drive is feasible using existing components. The next generation vehicle using new technologies is also predicted. Preface: The past decades have made the internal combustion engine the standard power source for vehicles. However, at the turn of the twentieth century there was much more variety with steam, electric, and gasoline power competing nearly equally. Electric vehicles were popular because they were quiet and clean, but they had short range and were only common in cities. Steam power was used for heavy duty jobs, but both steam and gas powered vehicles were dirty and difficult to operate. Ironically, it was the development of the electric starter motor which allowed easy operation of gasoline powered vehicles, and thus sealed the fate of early electric vehicles. One hundred years later, the transportation industry is again facing change. The petroleum reserves which have kept gasoline inexpensive are dwindling, and the air pollution which has been a constant side effect of internal combustion is now affecting the health of the population. This has brought electric vehicles back to the forefront of vehicle development, despite the fact that they still suffer from some of the same energy storage problems as their ancestors. The hybrid-electric vehicle has been developed as an method of addressing energy storage issues and improving the usefulness of the electric drivetrain. The delay in electric vehicle development is partly technical (batteries), but is mostly political. The petroleum industry and the Big 3 automakers have invested enormous amounts of money developing the current system, and they are loathe to change the business they have dominated for so long. Many small companies are rushing to fill the demand that the major automakers are stubbornly ignoring, and the next few years will bring many unique vehicles from a variety of sources. Table of Contents: Abstract: i Preface: ii Table of Contents: iii List of Figures: vi List of Tables: vii List of Abbreviations: viii Introduction: 1 Hybrid Design Overview: 5 Fundamental Question: 5 APU: 6 Drive Schemes: 9 Series: 9 Parallel: 13 EV Comparison: 16 Regeneration: 17 Battery Configuration: 19 Motors: 21 Climate Control: 24 Chassis: 27 Summary: 28 Technology Overview: 29 Batteries: 29 Electrochemical: 31 Flywheels: 41 Ultracapacitors: 42 Others: 44 Battery Comparison: 45 Motors: 46 DC Motors: 46 AC Motors: 49 Special Motors: 52 Alternative Fuels: 53 Reformulated Gasoline: 53 Natural Gas: 54 Propane: 55 Alcohol Fuels: 56 Hydrogen: 57 Summary: 58 Auxiliary Power Units: 60 Combustion Engines: 60 Fuel Cells: 66 Direct Conversion: 69 Summary: 70 Case Study: 72 All Wheel Drive: 74 Sport Utility Vehicle Definition: 76 Hybrid SUV: 78 Hybrid All Wheel Drive: 81 Series Scheme #1 : 82 Series Scheme #2; 85 Series Scheme #3: 89 IV Series Scheme #4: 91 Parallel Scheme #1 93 Parallel Scheme #2. 95 Parallel Scheme #3. 98 Battery Enclosure: 100 Calculations: 102 Road Loads: 103 Aerodynamics: 103 Rolling Resistance: 106 Roadway Grades: 109 Total Road Load: 111 Acceleration: 113 Other Losses: 114 Towing: 115 Battery Storage: 116 ZEV Range: 116 AAWD: 117 Fuel Consumption: 119 Results: 120 Design Solutions: 122 Near-Term Hybrid: 122 Mid-Term Hybrid: 124 Long-term Solution: 127 Conclusions: 129 Bibliography: 131 References: 135 Appendix: 154 List of Figures: Figure 1 APU Load-Leveling 7 Figure 2 Schematic of Series Hybrid 9 Figure 3 Schematic of Engine-Electric Hybrid 12 Figure 4 Schematic of Parallel Hybrid 13 Figure 5 Light Truck Sales Distribution 72 Figure 6 Series Scheme #1 82 Figure 7 Series Scheme #2 85 Figure 8 Series Scheme #3 89 Figure 9 Series Scheme #4 91 Figure 10 Parallel Scheme #1 93 Figure 1 1 Parallel Scheme #2 95 Figure 12 Parallel Scheme #3 98 Figure 13 Road Load vs. Temperature 105 Figure 14 Road Load vs. Wind Speed 106 Figure 15 Rolling Resistance vs. Speed 109 Figure 16 Vehicle on Grade 110 Figure 17 Road Load vs. Highway Grade 111 Figure 18 Road Load vs. Speed 112 VI List of Tables: Table 1 Selected UQM Motor Data 23 Table 2 USABC Goals 31 Table 3 Summary of Electrochemical Batteries 40 Table 4 Summary of Battery Technologies 45 Table 5 Sport Utility Comparison 77 Table 6 HE-SUV Specifications 79 Table 7 Series Scheme #1 83 Table 8 Series Scheme #2 86 Table 9 Series Scheme #3 90 Table 10 UQM Motor Data 90 Table 1 1 Series Scheme #4 92 Table 12 Parallel Scheme #1 94 Table 13 Parallel Scheme #2 96 Table 14 Parallel Scheme #3 99 Table 15 Battery Enclosure Issues 100 Table 16 1995 Sport Utility Data 102 Table 17 Rolling Resistance Coefficients 108 Table 18 Fuel Consumption 120 Table 19 Near-term Hybrid Components 123 Table 20 Mid-term Hybrid Components 125 VII List of Abbreviations: ABS Anti-lock Brakes APU Auxiliary Power Unit AAWD Adaptive All Wheel Drive AWD All Wheel Drive CARB California Air Resources Board CNG Compressed Natural Gas DOE United States Department of Energy EV Electric Vehicle EPA Environmental Protection Agency FFV Flexible Fuel Vehicle HEV Hybrid-Electric Vehicle HEVC Hybrid Electric Vehicle Challenge, student competition ICE Internal Combustion Engine LEV Low Emission Vehicle, defined by CARB LNG Liquid Natural Gas MCFC Molten Carbonate Fuel Cell PAFC Phosphoric Acid Fuel Cell PEM Proton Exchange Membrane PNGV Partnership for a New Generation Vehicle RFG Reformulated Gasoline SOC State of Charge SOFC Solid Oxide Fuel Cell ULEV Ultra-Low Emission Vehicle, defined by CARB USABC United States Advanced Battery Consortium ZEV Zero-Emission Vehicle VIII Introduction: As the remaining stocks of petroleum are steadily depleted, and smog and air pollution become extremely serious concerns, pressure is growing to evaluate our transportation systems. Two key objectives have been identified in response to these issues: reduction of oil consumption, and reduction of air pollution levels. The problem of air pollution has received serious investigation, and the automobile industry is among the first to be regulated. The California Air Resources Board (CARB) is leading the way by setting strict standards for allowable vehicle emissions in the state of California. The emissions standards progressively toughen from low emission vehicle (LEV) down to zero emission vehicle (ZEV), and a timeline has been established which dictates how many vehicles of each level may be sold each year. Many other governing bodies have adopted the California regulations or passed similar legislation to control the environmental performance of new vehicles (exhaust emissions and fuel consumption). The implications of these regulations and their effectiveness in controlling the environmental issues which they address is still the subject of active debate. The questions raised by these debates and the arguments set forth by all involved parties are well documented in other sources, and will not be addressed in this paper. Regardless of the debate, a new generation of vehicles is coming, and they promise to be very different from current automobiles. Attaining the improvements which are mandated in these regulations represents a challenging task. Much of the research and subsequent development of the diverse technologies which will be required is beyond the means of any single company. Many groups and consortiums have been formed to help distribute the work load. Nearly all of these groups represent a cooperative effort between government and industry. Since the government is mandating the speed with which these changes must occur1, it is assuming a key role in their development. The Hybrid Propulsion Plan is one such cooperative effort between the U.S. Department of Energy (DOE) and the major U.S. automakers. The efforts of this group are aimed at the short term development of vehicles which can be available at the turn of the century. The main goal of all the projects is to increase the fuel economy and lower the exhaust emissions of new vehicles. Secondary goals involve the appropriate development of new technologies and alternative fuels to support future improvements in vehicle performance. Current research is laying the groundwork for the Partnership for a New Generation Vehicle (PNGV). This program is another joint venture between government and industry, and has ambitious goals such as tripling average fuel economy and improving safety and performance.