The work in this paper presents techniques for design, development, and control of hybrid electric vehicles (HEV's), Toward these ends, four issues are explored. First, the development of HEV's is presented, This synopsis includes a novel definition of degree of hybridization for automotive vehicles, Second, a load-leveling vehicle operation strategy is developed. In order to accomplish the strategy, a fuzzy logic controller is proposed. Fuzzy logic control is chosen because of the need for a controller for a nonlinear, multidomain, and time-varying plant with multiple uncertainties, Third, a novel technique for system integration and component sizing is presented. Fourth, the system design and control strategy is both simulated and then implemented in an actual vehicle. The controller examined in this study increased the fuel economy of a conventional full-sized vehicle from 40 to 55.7 mi/h and increased the average efficiency over the Federal Urban Driving Schedule from 23% to 35.4%, The paper concludes with a discussion of the implications of intelligent control and mechatronic systems as they apply to automobiles.
