LNG Vehicle Fuel Pressure Strategy Alternatives
Liquefied natural gas (LNG) use as a heavy-duty vehicle fuel is increasing. Current generation high-horsepower natural gas engines used in trucks and buses typically require fuel supply pressures in the range 75 to 120 psig. LNG delivered to the fueling station usually has a saturation pressure of roughly 10 psig. A variety of approaches may be used to provide the required fuel pressure increase. Each approach involves a different on-vehicle fuel system design, and LNG station capabilities must accommodate vehicle fuel system requirements. This paper describes various LNG vehicle fuel system design strategies including key tradeoffs, implications on station requirements, and developmental status. The most commonly used fuel system design receives and stores the LNG in the vehicle tank at a saturation pressure at least equal to the engine fuel supply pressure requirement.