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A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example on

A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

대표청구항 ▼

1. In a vehicle propulsion system powered by a fuel cell system, a method for rapidly rapidly shutting down the fuel cell system including a fuel cell stack with anode and cathode inlets, an H2 supply, an air supply, the method comprising: providing an anode bypass valve selectively permitting commu

1. In a vehicle propulsion system powered by a fuel cell system, a method for rapidly rapidly shutting down the fuel cell system including a fuel cell stack with anode and cathode inlets, an H2 supply, an air supply, the method comprising: providing an anode bypass valve selectively permitting communication between the H2 supply and the anode inlet, and a cathode bypass valve selectively permitting communication between the air supply and the cathode inlet; instantaneously venting the anode inlet; activating the anode and cathode bypass valves to divert H2 and air flows, respectively, from the anode and cathode inlets over a predetermined time period corresponding to a period of time over which the fuel cell stack is able to withstand a pressure differential; and, instantaneously venting the cathode inlet after the cathode bypass valve has diverted most or all of the air flow from the cathode inlet.