Development of Auxiliary Power Units for Electric Hybrid Vehicles.

Electric drive is being considered for a wide variety of urban vehicles. Larger urban commercial vehicles such as shuttle and transit buses, various delivery and service vehicles such as panel and step vans, and garbage trucks and school buses are particularly well suited for this type of propulsion system due to their relatively short operating routes, operation and maintenance from central sites. Furthermore, these vehicles contribute a proportionately large amount to metropolitan air pollution by virtue of their continuous operation in those areas. Thus, reductions of emissions from these vehicles can have a large impact on urban air quality. It is, therefore, a necessity to develop auxiliary power units APUs that minimize emissions and in addition, increase range of electric vehicles. This report focuses on the first phase study of the development of APUs for large, electric drive commercial vehicles, intended primarily for metropolitan applications. This paper 1 summarizes the differences between available mobile APUs and Electric Vehicle APU requirements, 2 describes the major components in APUs, and 3 discusses APU integration issues. During this phase, three potential APU manufacturers were identified and selected for development of prototype units at 25 kW and 50 kW power levels.