Electric and Hybrid Electric Vehicle Study Utilizing a Time-Stepping Simulation 929136

Advanced power technologies are being investigated by the Power Technology Division (PTD) of the NASA Lewis Research Center (LeRC). These technologies are varied and the applications are diverse. Among these technologies are batteries, high efficiency induction motors, high frequency electric power distribution, dynamic energy storage, and Stirling cycle machines. While the emphasis of the PTD research is the application of these technologies to fulfill space power requirements, terrestrial applications may also exist.

Future regulation of vehicular emission levels has prompted a recent increase in interest in electric and hybrid vehicles. Electric vehicles have been limited in range and performance by the storage capability of currently available batteries. As an alternative, the hybrid vehicle may render a more near term solution to provide an environmentally safe, full performance vehicle. With proper optimization and integration of the subsystems, a hybrid vehicle has the potential for reduced emissions and increased fuel economy, with comparable range and performance relative to the present day automobile.

This paper describes a study performed to assess the applicability of NASA's advanced power technologies to electric and hybrid vehicles. In support of this study, a time-stepping computer simulation was developed to model electric and hybrid vehicles operating over the Federal Urban Driving Schedule (FUDS). Variations in vehicle configuration and subsystem specifications are possible. By the nature of a time-stepping simulation, both the energy and power demands of the FUDS are taken into consideration, consequently vehicle economy, range and performance are addressed simultaneously. Features of the LeRC simulation include options to evaluate abrupt power requirements such as 0-30 mph and 0-60 mph acceleration times, and for the user to create, store and edit alternate driving cycles. A description of simulation is presented along with initial results of the study.