Development of a Small Multi-fuel Capability APU for Abrams, Bradley, and Stryker Vehicles

The Army is currently interested in obtaining small engines that are lightweight, reliable, durable, fuel efficient, and low cost for many applications. One application of this small engine technology is for use as an auxiliary power unit (APU) for the Abrams, Bradley, and Stryker vehicles. The APU would provide power for onboard electronics and reduce the need to run the main engine continuously. The proposed APU would also be an improvement over existing units in terms of weight, noise, and fuel consumption. In Phase I, Mainstream will perform a detailed simulation of the proposed engine using advanced software modeling that is a standard in the engine design industry. Using the results of this simulation, an initial design for the 8-kW engine will be obtained. Various technologies to improve performance of the engine will be demonstrated on Mainstream’s 2-kW diesel generator. Performance-enhancing technologies that will be investigated in Phase I include turbo/super-charging, electronic fuel injection, variable valve timing and camless valve actuation.