Abstract: A process for manufacturing a compressed gas tank that includes a combination of an injection molding process and a rotomolding process. In a first step, a boss to be positioned in the opening of an outer structural layer of the tank is provided and a thin portion of the liner is injection molded to the boss so that a channel within the boss is filled with the liner material to increase the seal integrity between the boss and the liner. Once the liner material is hardened, the surface of the injection molding liner portion is cleaned. Next, a rotomolding process is performed to mold the remaining portion of the liner to the boss. During the rotomolding process, the injection molded portion of the liner melts to be part of the liner made during the rotomolding process.

Abstract: A heated O-ring that has particular application for providing sealing in the connector region of a compressed hydrogen storage tank in a fuel cell system. In one embodiment, an electrical heating wire is wound through the O-ring so that resistive heating is provide by applying an electrical potential to the wire so that the temperature of the O-ring does not decrease below a predetermined temperature. In another embodiment, electrical heating elements are provided adjacent to and in contact with the O-ring, where an electrical potential applied to the heating elements causes the heating elements to maintain the temperature of the O-ring.

Abstract: A liquid hydrogen tank assembly that employs a level sensor inductively coupled through the tank walls so as to minimize one conductive heat path through the tank walls. The tank assembly includes an inner tank and an outer tank having a vacuum layer therebetween to maintain the liquid hydrogen within the inner tank under cryogenic temperatures. A capacitive level sensor is positioned within the inner tank and provides an electrical indication of the level of the liquid hydrogen within the inner tank. The level sensor is electrically coupled to an inner coil within the inner tank. An outer coil is provided proximate the outer tank wall and is electrically coupled to a signal processing and conditioning circuit.

Abstract: A shut-off valve that has particular application for opening and closing a compressed hydrogen storage tank. In one embodiment, the valve includes two valve sealing members where one side of one valve sealing member is on the high pressure side of the valve and an opposing side of the other valve sealing member is on the high pressure side of the valve. Therefore, the pressure applied to the two valve sealing members offset each other so that less force is required to open the valve against the high pressure. In another embodiment, one of the sealing members is replaced with a bellows.

Abstract: A pressure regulator that has particular application for an anode input side of a fuel cell system to provide the desired large turn-down ratio. The pressure regulator includes at least two valves positioned in parallel where the first valve is smaller than the second valve. The first valve is opened and closed and the second valve is maintained closed at low flow rates. Once the flow rate is high enough, the first valve is maintained completely open, and the second valve is opened and closed to control the flow at high flow rates.

Abstract: A fluid supply system is provided which includes a filling station operable to provide a fluid to a fuel storage vessel. The fluid supply system is operable in a first mode to provide a fluid in a liquid phase from the filling station to the storage vessel and is operable in a second mode to prevent the supply of the fluid to the storage vessel. The storage vessel is in fluid communication with the fluid supply system and is operable to receive the fluid in the liquid phase when the fluid supply system is in the first mode and discharge the fluid in a gaseous phase to the filling station. At least one sensor is in communication with the discharge passage and the fluid supply, and operates to cause the fluid supply to operate in the second mode in response to a detected pressure drop.

Abstract: A fuel cell system utilizes at least one flow restricting device to vary the stoichiometric quantity of cathode reactant flowing to two discrete cathode sides of the fuel cell system. The varying of the stoichiometric quantity of cathode reactant can be between two predetermined values. The varying of the stoichiometric quantity can be during a steady state power demand placed on the system and/or during transients in a power demand placed on the system. The airmover that supplies the cathode reactant stream can be operated in a substantially continuous manner during a continuous power demand placed on the fuel cell system.

Abstract: A hydrogen distribution valve for alternately distributing gaseous and liquid hydrogen from a tank is disclosed. The hydrogen distribution valve includes a valve housing having a gaseous hydrogen inlet, a liquid hydrogen inlet, a hydrogen outlet and a reference pressure port for receiving a reference hydrogen pressure. A rocker valve is provided in the valve housing for alternately sealing the gaseous hydrogen inlet and the liquid hydrogen inlet. A bias mechanism engages the rocker valve for biasing the rocker valve in sealing engagement with said liquid hydrogen inlet. A valve membrane is provided in fluid communication with the reference pressure port and engages the valve head for biasing the valve head in sealing engagement with the gaseous hydrogen inlet.

Abstract: A liquid hydrogen tank assembly that employs a level sensor inductively coupled through the tank walls so as to minimize one conductive heat path through the tank walls. The tank assembly includes an inner tank and an outer tank having a vacuum layer therebetween to maintain the liquid hydrogen within the inner tank under cryogenic temperatures. A capacitive level sensor is positioned within the inner tank and provides an electrical indication of the level of the liquid hydrogen within the inner tank. The level sensor is electrically coupled to an inner coil within the inner tank. An outer coil is provided proximate the outer tank wall and is electrically coupled to a signal processing and conditioning circuit.

Abstract: A Z-shaped, multi-channel conduit segment configured to transfer cryogenic fluid into and out of a cryogenic storage tank with minimal heat transfer. The conduit segment comprises a first channel operable to transport a cryogenic liquid from a supply source to the storage tank, and a second channel operable to transport gas from the storage tank to an end user. The conduit is preferably formed from a single piece of material, such that the first channel is separated from the second channel.

Abstract: A fuel cell system that employs one or more injectors in an anode inlet unit for providing hydrogen flow control to a fuel cell stack in the system. At a low flow rate, the duty cycle of one of the injectors is controlled and the other injectors are closed. As the flow rate requirements increase, the duty cycle of the first injector is increased until it is completely open. The duty cycles of the other injectors are then controlled in the same manner in succession. The anode inlet unit may include a valve for directing the hydrogen supply gas to other devices in the fuel cell system. Additionally, a valve can be provided in the unit that receives a flow of air to purge the anode side of the fuel cell stack.

Abstract: A fuel cell system including a combined injector/ejector system. The pressure of a hydrogen gas being injected into the fuel cell system by the injector acts as a pump that draws an anode exhaust gas being carried by the ejector back into the fuel cell system. The respective gases mix together in proximity to the ejector prior to being introduced back into the fuel cell system. A pressure controller can be provided to control the pressure of the hydrogen gas applied to the injector to more effectively draw the anode exhaust gas. In this manner, the need for a separate pump for the ejector, and the energy required for its operation, is eliminated or at least lessened, thus increasing the overall energy efficiency of the fuel cell system.

Abstract: A coolant reservoir for use in a coolant system of a fuel cell stack is provided, and includes a catalyst element disposed in the vessel and being capable of reacting hydrogen within the vessel with oxygen from outside air. The catalyst element includes a heating system for heating the catalyst element to a predetermined temperature.

Abstract: A mechanization of a fuel cell system and a method of operating the same is provided which simplifies the start-up of the fuel cell system. The fuel cell system can be started up without using any battery derived high voltage power to drive a high voltage compressor. The present invention provides for the use of a low voltage blower to provide oxygen to the cathode side of the fuel cell stack to enable start-up of the fuel cell stack without the initial use of a high voltage compressor. The low voltage blower can be powered by a low voltage power source and/or the voltage produced by the fuel cell stack.

Abstract: A fuel cell system comprising a plurality of fuel cells combined together to form a fuel cell stack, with the fuel cell stack having an anode side with an inlet for a fuel and an outlet for non-consumed fuel and exhaust gases arising at the anode side as well as a cathode side with an inlet for a gaseous oxidising agent such as air and an outlet for exhaust gases which arise at the cathode side, and a compressor having a compressor inlet and a compressor outlet, the compressor outlet of which is connected to the oxidising agent inlet of the fuel cell stack provided at the cathode side, is characterised in that a gas dynamic pressure wave machine having a driven rotor is provided, with an inlet for exhaust gases arising at the cathode side, an inlet for fresh oxidizing agent, an outlet for oxidising agent compressed by the cathode side exhaust gases and also an outlet for the cathode side exhaust gases being associated with the rotor and with the outlet for the oxidising agent compressed by the cathode side ex