Liquefied natural gas (LNG) use in heavy-duty vehicles provides important air quality and energy security benefits over gasoline and diesel fuels. However, high efficiency (e.g., direct-injection) natural gas engines are needed for economic viability, and some, like those employing direct injection, will require a high-pressure gas supply. This project will develop and evaluate the design of a 3000-psi LNG fuel system. The system stores LNG at conventionally-low pressures and utilizes an innovative waste-heat-driver reciprocating pump that minimizes cavitation, but can process liquid-vapor mixtures when necessary. The pump drive utilizes the higher temperature of the engine coolant; this makes the system self-powered because it requires no engine driveshaft connections and thus consumes no engine power. Phase I will include design analyses and tradeoff studies to determine the best suited configurations and operating conditions. Bench tests of critical components will be conducted, and a preliminary system design will be established. Prototype system fabrication, laboratory testing, and on-road demonstration is anticipated in Phase II.
Commercial Applications and Other Benefits as described by the awardee:This LNG fuel system solves the fuel supply pressure problem faced by heavy-duty vehicles using high-efficiency, low-emissions direct-injection natural gas engines. Studies indicate that this is an economically-viable natural gas vehicle application and that a commercial market will develop for this type of equipment.
