Abstract: A fuel processor control system for a fuel cell stack includes water and fuel metering devices that control water and fuel provided to the fuel processor. An air flow rate sensor generates an air flow rate signal based on air flowing from a compressor to the fuel processor. A valve is located between the fuel processor and the fuel cell stack. A controller controls the valve and the water and fuel metering devices based on the air flow rate sensor. Other feedback signals such as stack voltage, stack cell voltage variation, pressure differential across the valve, and mass flow rate between the valve and the fuel cell stack can augment or be substituted for the air flow rate feedback signal. The fuel processor can be a partial oxidation reformer a steam reforming reactor, an auto thermal reformer or any combination thereof. The system may also include a water as shift reactor and a preferential oxidation reactor for carbon monoxide reduction.

Abstract: A venting methodology and pressure sensing and vent valving arrangement for monitoring anode bypass valve operating during the normal shutdown of a fuel cell apparatus of the type used in vehicle propulsion systems. During a normal shutdown routine, the pressure differential between the anode inlet and anode outlet is monitored in real time in a period corresponding to the normal closing speed of the anode bypass valve and the pressure differential at the end of the closing cycle of the anode bypass valve is compared to the pressure differential at the beginning of the closing cycle. If the difference in pressure differential at the beginning and end of the anode bypass closing cycle indicates that the anode bypass valve has not properly closed, a system controller switches from a normal shutdown mode to a rapid shutdown mode in which the anode inlet is instantaneously vented by rapid vents.