Abstract: A fuel cell system includes a fuel cell stack, an ejector in fluid communication with the fuel cell stack and having a converging-diverging (CD) nozzle with a hydrogen feed nozzle and a recirculation conduit upstream of a throat of the CD nozzle, and a thermal source configured to heat the ejector. A hydrogen supply assembly for a fuel cell system includes an ejector having a converging-diverging (CD) nozzle and a mixing chamber upstream of the CD nozzle. The mixing chamber has a recirculation conduit and a hydrogen feed nozzle. A thermal source is configured to heat the ejector. A method of controlling a hydrogen supply device for a fuel cell includes, in response to detecting a heating condition at fuel cell start up, controlling a thermal source to heat an ejector upstream of an anode stack to prevent ice formation in the ejector.

Abstract: A fuel cell system includes a fuel cell stack, an ejector in fluid communication with the fuel cell stack and having a converging-diverging (CD) nozzle with a hydrogen feed nozzle and a recirculation conduit upstream of a throat of the CD nozzle, and a thermal source configured to heat the ejector. A hydrogen supply assembly for a fuel cell system includes an ejector having a converging-diverging (CD) nozzle and a mixing chamber upstream of the CD nozzle. The mixing chamber has a recirculation conduit and a hydrogen feed nozzle. A thermal source is configured to heat the ejector. A method of controlling a hydrogen supply device for a fuel cell includes, in response to detecting a heating condition at fuel cell start up, controlling a thermal source to heat an ejector upstream of an anode stack to prevent ice formation in the ejector.

Abstract: A fuel cell system may include a cathode loop having an operating pressure during fuel cell system operation. The cathode loop may include a normally open mechanical check valve disposed at a water pooling location within the loop and having a cracking pressure approximately equal to the operating pressure.

Abstract: A fuel cell system has a compressor delivering compressed gas to a fuel cell stack and a control valve affecting the flow of compressed gas. A load dump condition is determined for the fuel cell stack. The flow through the compressor is increased and the additional flow diverted away from the fuel cell stack by the control valve to provide additional load for the fuel cell stack. The fuel cell stack may then be operated at a higher output power for the purpose of generating more waste heat to more rapidly warm itself.

Abstract: A fuel cell system has a compressor delivering compressed gas to a fuel cell stack and a control valve affecting the flow of compressed gas. A load dump condition is determined for the fuel cell stack. The flow through the compressor is increased and the additional flow diverted away from the fuel cell stack by the control valve to provide additional load for the fuel cell stack. The fuel cell stack may then be operated at a higher output power for the purpose of generating more waste heat to more rapidly warm itself.

Abstract: A fuel cell system has a compressor delivering compressed gas to a fuel cell stack and a control valve affecting the flow of compressed gas. A load dump condition is determined for the fuel cell stack. The flow through the compressor is increased and the additional flow diverted away from the fuel cell stack by the control valve to provide additional load for the fuel cell stack. The fuel cell stack may then be operated at a higher output power for the purpose of generating more waste heat to more rapidly warm itself.

Abstract: A fuel cell system may include a cathode loop having an operating pressure during fuel cell system operation. The cathode loop may include a normally open mechanical check valve disposed at a water pooling location within the loop and having a cracking pressure approximately equal to the operating pressure.

Abstract: A system and method for delivering an input fluid stream through a fuel cell stack and discharge an unused fluid stream is provided. An inlet of the fuel cell stack is adapted to receive the fluid stream. An ejector is configured to combine the supply fluid stream and the unused fluid stream to generate the input fluid stream and control the flow of the input fluid stream to the fuel cell stack. A blower is configured to control the flow of the unused fluid stream to the ejector. A bypass valve is configured to control the flow of the unused fluid stream to the blower and to the ejector.

Abstract: A fuel cell system has a compressor delivering compressed gas to a fuel cell stack and a control valve affecting the flow of compressed gas. A load dump condition is determined for the fuel cell stack. The flow through the compressor is increased and the additional flow diverted away from the fuel cell stack by the control valve to provide additional load for the fuel cell stack. The fuel cell stack may then be operated at a higher output power for the purpose of generating more waste heat to more rapidly warm itself.

Abstract: A system and method for delivering an input fluid stream through a fuel cell stack and discharge an unused fluid stream is provided. An inlet of the fuel cell stack is adapted to receive the fluid stream. An ejector is configured to combine the supply fluid stream and the unused fluid stream to generate the input fluid stream and control the flow of the input fluid stream to the fuel cell stack. A blower is configured to control the flow of the unused fluid stream to the ejector. A bypass valve is configured to control the flow of the unused fluid stream to the blower and to the ejector.