Demonstration of a Proton Exchange Membrane Fuel Cell as an Auxiliary Power Source for Heavy Trucks

Class 8 trucks idling consume significant amounts of diesel fuel each year in North America and abroad. Engine idling occurs to power sleeper compartment accessories (air conditioners, refrigerators, televisions), and to avoid start-up problems. The alternative power sources available to reduce the need for idling (i.e. battery packs, auxiliary generators, direct-fired heaters, absorption coolers) all have severe economic and technical drawbacks that have limited their market acceptance. Freightliner Corporation, in conjunction with its development partner XCELLSiS Corp. has constructed a fully functioning concept demonstration vehicle that utilizes Proton Exchange Membrane (PEM) fuel cell technology in an auxiliary power unit (FC APU). While fuel cell powertrains continue to face significant technical and economic barriers, with additional development truck auxiliary power applications may offer a viable near-term market for small (1 - 5 kW) fuel cells. This paper describes the program motivation as well as both the overall system configuration and integration of the APU. Also presented are preliminary estimates of the reduction in emissions, fuel consumption, and cost from reducing truck idling. Very conservative, preliminary estimates are that idling costs $3127 to $4169 in fuel alone per year. Idling is estimated to contribute 0.2 - 0.6 metric tons of nitrogen oxide emissions per vehicle over per year for late model tractors.