Hybrid Internal Combustion Engine: Driving a Vehicle Using Air Compressed in Braking

After the oil crisis of the 1970's, stringent government standards placed on automobile manufacturers have led the industry to explore more fuel efficient alternatives to the vehicle with a conventional internal combustion engine/transmission powertrain. This is the motivation behind Mr. David F. Moyer's hybrid internal combustion engine concept. A vehicle using this engine should attain higher fuel economy levels as a result of kinetic energy recovery and reuse (achieved by using the engine as an air compressor during braking, storing the compressed air, and then utilizing that air to turn the engine and drive the vehicle), cylinder disabling, and the elimination of idling losses. Data of transmission input power for Ford Motor Company's P2000 vehicle while driven through 1373 seconds of typical urban driving (CVS cycle) were used, combined with a model to estimate engine friction, to carry out an available energy analysis of the hybrid engine. An air processing efficiency was incorporated into the analysis to determine how irreversible the air storage/use processes were. Fuel economy was estimated for the different operating conditions of the concept by matching Ford's 1.8-litre Zetec engine to the vehicle and using the fuel consumption map for that engine. The vehicle with the baseline engine yields 32.6 mpg. Adding cylinder disabling raises this value to 36.8 mpg. Ultimately, if reversible hybrid operation is added, the best possible fuel economy this concept can achieve is 52.4 mpg, for a total maximum savings of 38% in fuel consumption. Using simple thermodynamic models of a braking and an air driving event, we predicted maximum values of 85% and 88% for the air processing efficiency in the braking and the air driving case, respectively. An overall value of 65% was chosen for the efficiency, resulting in a maximum fuel economy of 48.1 mpg and fuel savings of 32%. The analysis above led us to conclude that engine friction plays a significant role in reducing the benefit of this hybrid concept. Furthermore, fully variable valve timing and cylinder disabling improve fuel economy for a conventional engine significantly, and they are essential in minimizing the thermodynamic losses involved in hybrid operation. Therefore, we recommend that methods to reduce engine friction as well as means to implement fully variable valve timing modifications to an internal combustion engine be explored further. Thesis Supervisor: John B. Heywood Title: Sun Jae Professor of Mechanical Engineering Acknowledgments Having the opportunity to work on this project and obtain useful results has been a very pleasant and filling experience. I have always had a passion for automobiles, and my participation in this project has taught me a great deal and allowed me to contribute my two cents to the car industry. My supervisor, Professor John B. Heywood, has been an invaluable resource throughout these last two years. As a teacher, both in the classroom and in project discussions, and as a researcher, Prof. Heywood has taught me many things about real problem solving and research, internal combustion engines, thermodynamics, and the automotive industry. Most importantly, though, he has taught me to always keep things in perspective and persevere, no matter how difficult the task at hand seems. My gratitude goes to him for being so committed to education, being an excellent advisor who is always willing to listen and help, and for giving me the opportunity to work with him in this project. This project would have never happened had it not been for the impressive creativity of Mr. David F. Moyer. His hybrid internal combustion engine concept is an amazing display of ideas to improve performance, in all senses, of the automobile as we know it. I thank him very much for allowing me to benefit from his expertise and knowledge of the automobile industry. Throughout most of the duration of this project, we worked closely, and I very much appreciate his always being willing to be of assistance and the multiple times that he and his wife Pat received me at their home for discussions on the hybrid. I will always remember our conversations on all the interesting concepts he created and dealt with while working in the automobile industry. I am extremely grateful to Mr. Bradford Bates and to his corporation, Ford Motor Company, for sponsoring this project and for allowing me to play an important role in it. His support was extraordinary, and he always made sure we got the information we needed to continue with our tasks. I will always be appreciative of the time and effort of the people at the Ford Research Laboratory who provided the data needed for our project and who were always in the disposition to answer questions give us useful feedback. My time at the Sloan Automotive Laboratory would not have been the same without the people here. A major THANK YOU goes to my office mates, who are people I could always count on for help or advice. I thank you all for bearing with me throughout the job search process; I'm sure you are twice as happy as I am that the interviewing is all over! To my friend Robert Meyer, thanks for always listening to me and sharing your experience and wisdom. My buddies Mark Dawson and Cornelius O'Sullivan (the Irish Connection), thanks for your friendship and for all the innovative jokes. Norman Peralta... he has been gone for a year, but last year he was a wonderful source of moral support and still is a good friend. Ertan Yilmaz, I cannot thank you enough for all your useful lessons of the Turkish language; they have been very handy in defending myself... I promise Michaela Wiegel, whose name I still cannot pronounce correctly, that I'll work on my skills in German. Brad VanDerWege and Mike Shelby, I thank you guys for the help in I.C.E. related questions; you certainly know your stuff! Outside the office, everybody contributed to making the lab a better place for me. Jim Cowart has been a great friend and a very useful resource. His feedback was very valuable when the time to choose a job came around, and the discussions with him about his work in the auto industry have been very interesting. Chris O'Brien, Steven Casey, David Kayes, Derek Kim, Bertrand Lecointe, Helen Liu, Matt Rublewski, Alan Shihadeh, Dai Suzuki, and Benoist Thirouard have all been a pleasure to interact with. I would like to thank all the staff of the lab for their help and support. Karla Stryker and Nancy Cook were always helpful and friendly. Although I did not work in the lab area, I had the opportunity to get to know and interact with Brian Corkum and Peter Menard. I thank you both for your friendship and for all the things you taught me about real car work. Last, but certainly not least, I thank my family, particularly my mother, and all my friends for their confidence and faith in me. Carlos A. Herrera May 8, 1998