Abstract: A fuel cell having a cathode and an anode. The cathode has an inlet and an outlet. The fuel cell also includes at least one of a first valve and a second valve. The first valve is situated at and connected to the cathode inlet. The second valve is situated at and connected to the cathode outlet. The fuel cell system also includes a controller configured to control the first and second valves during a first operating condition and a second operating condition. The first operating condition includes the transition of the fuel cell system from an operational state to a non-operational state. The second operating condition includes the transition from a non-operational state to an operational state.

Abstract: In at least one embodiment, a fuel cell anode exhaust system includes a fuel cell anode having an input and an output. The system also includes a first conduit loop communicating with the anode input and output. The system also includes a second conduit loop having an input and an output. The input and output communicate with the first conduit loop. A gas separator is disposed on the second conduit loop for purifying an exhaust stream fed into the gas separator.

Abstract: A fuel cell system may include a fuel cell stack, a manifold in fluid communication with the stack, and a pressure sensor. The pressure sensor may include a housing defining a chamber in fluid communication with the manifold, a pressure sensing element disposed within the chamber, and a heating element disposed within the chamber.

Abstract: A fuel cell system includes a primary hydrogen source capable of communicating with a fuel cell anode. The system also includes a secondary hydrogen source communicating with the primary hydrogen source. A first valve is positioned downstream of the secondary hydrogen source. The valve allows hydrogen from the secondary source to communicate with hydrogen from the primary source downstream of the valve and upstream of the fuel cell anode.

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 system for delivering an input fuel stream to a fuel cell stack to generate electrical current and to discharge an unused fuel stream is provided. A supply produces a supply fuel stream. An ejector combines a purged fuel stream and the supply fuel stream and controls the flow of the input fuel stream to the fuel cell stack. A purging arrangement receives the unused fuel stream which includes impurities and purges the impurities from the unused fuel stream to generate the purged fuel stream. A bypass valve is capable of delivering the purged fuel stream to the ejector. A blower is capable of delivering the purged fuel stream to the ejector. A controller controls one of the bypass valve and the blower for delivering the purged fuel stream to the ejector based on the amount of electrical current generated by the fuel cell stack.