Hydrogen Fuel Pressure Energy Recovery for Hydrogen Engine Vehicles

A fuel system for a hydrogen-fueled internal combustion engine vehicle. A compressor/expander is installed in fluid connection between the fuel tank and the engine's fuel delivery system. The compressor/expander operates in compressor mode when the hydrogen fuel in the fuel tank is below a pressure desired for fuel delivery. It operates in expander mode when the hydrogen fuel in the fuel tank is above the desired pressure. The compressor/expander has inlet and outlet metering valves. A controller receives fuel tank pressure and temperature measurements and calculates timing of the metering valves to maintain the desired pressure into the fuel delivery system.