Abstract: In at least one embodiment, a purge system for a fuel cell stack is provided. The system comprises a blower, a differential pressure sensor and a purge valve. The blower delivers a recirculated gas back to the stack at varying electrical power levels and blower speeds. The differential pressure sensor senses pressure of the recirculated gas across the blower. The purge valve purges the recirculated gas based on at least one of a blower power level, a blower speed, and the pressure of the recirculated gas.

Abstract: An apparatus for providing a humidified cathode fluid stream to a fuel cell stack is disclosed. The apparatus comprising a first humidifier including membranes and a compressor. The first humidifier is configured to receive a cathode fluid stream and to humidify the cathode fluid stream with water from a recirculated fluid stream to provide a first humidified cathode stream. The compressor is configured to receive the first humidified cathode stream and to provide a first pressurized humidified cathode stream. The compressor is further configured to generate a pressure differential across the first humidifier such that the membranes are humidified with the water.

Abstract: In at least one embodiment, a purge system for a fuel cell stack is provided. The system comprises a blower, a differential pressure sensor and a purge valve. The blower delivers a recirculated gas back to the stack at varying electrical power levels and blower speeds. The differential pressure sensor senses pressure of the recirculated gas across the blower. The purge valve purges the recirculated gas based on at least one of a blower power level, a blower speed, and the pressure of the recirculated gas.

Abstract: In at least one embodiment, a purge system for a fuel cell stack is provided. The system comprises a blower, a differential pressure sensor and a purge valve. The blower delivers a recirculated gas back to the stack at varying electrical power levels and blower speeds. The differential pressure sensor senses pressure of the recirculated gas across the blower. The purge valve purges the recirculated gas based on at least one of a blower power level, a blower speed, and the pressure of the recirculated gas.

Abstract: A fuel cell system comprising a fuel cell which contains an anode and a cathode, further comprising a cathode compressor to supply process air to the fuel cell, and an anode compressor to supply fuel gas to the fuel cell, whereby the cathode compressor and the anode compressor can be driven by a common motor drive, and whereby an automatic clutch is provided to couple and decouple the driving of the cathode compressor and the anode compressor.

Abstract: In a process and apparatus for two-stage supercharging of process air for a fuel cell, in one of the two charging stages, supercharging taking place by means of a displacement machine. In the other charging stage, supercharging is performed by means of a combined expansion and compression machine. Energy is recovered from the exhaust gas of a fuel cell by means of the combined expansion and compression machine.

Abstract: In a process and apparatus for two-stage supercharging of process air for a fuel cell, in one of the two charging stages, supercharging taking place by means of a displacement machine. In the other charging stage, supercharging is performed by means of a combined expansion and compression machine. Energy is recovered from the exhaust gas of a fuel cell by means of the combined expansion and compression machine.

Abstract: In a process and apparatus for two-stage supercharging of process air for a fuel cell, in one of the two charging stages, supercharging taking place by means of a displacement machine. In the other charging stage, supercharging is performed by means of a combined expansion and compression machine. Energy is recovered from the exhaust gas of a fuel cell by means of the combined expansion and compression machine.