Hydrogen fuel supply system

Abstract

A fuel supply system is provided for engines which are adapted to operate on gaseous hydrogen fuel and which utilize a fuel tank containing a metal hydride for the storage of hydrogen. The system provides for high pressure operation when the hydride in the fuel tank is fully charged with hydrogen, as well as for operation at low pressures to allow maximum utilization of the hydrogen stored in the hydride. A supply conduit, which can supply the hydrogen needed during normal operation of the engine with minimal pressure drop, connects the storage tank to the fuel intake of the engine. A bypass conduit is provided having one end thereof connected to the supply conduit and its other end reconnected to the supply conduit downstream of the first connection. Valve means are adapted to direct the flow of hydrogen either directly through the supply conduit or to divert the flow of hydrogen from the supply conduit through the bypass conduit and back to the supply conduit downstream from the valve means. A pressure regulator is included in the bypass conduit which is capable of regulating downstream pressure at a preset pressure when the upstream pressure is greater than the preset pressure. A controller monitors the downstream pressure and when the monitored pressure falls sufficiently below the preset pressure of the regulator, the controller changes the valve means so that the hydrogen flows directly through the supply conduit. Thus, when the storage tank supplies high pressure hydrogen to the supply conduit, the hydrogen is routed through pressure regulating means in the bypass conduit, and when the pressure from the storage tank decreases below the regulated pressure, the hydrogen is routed through the supply conduit thereby avoiding substantial pressure drops as it flows from the storage tank to the engine.