Abstract: A method and apparatus for thermal control of air flow in a fuel cell system, capable of accurately controlling the temperature of the air stream entering the water vapor transfer unit, maintaining a desired temperature set-point, and minimizing the time required for the air stream to reach the optimum operating temperature.

Abstract: A system and method for quickly heating a fuel cell stack at fuel cell system start-up. The fuel cell system includes a three-way valve positioned in the anode exhaust that selectively directs the anode exhaust gases to the cathode input of the fuel cell stack so that hydrogen in the anode exhaust gas can be used to heat the fuel cell stack. During normal operation when the fuel cell stack is at the desired temperature, the three-way valve in the anode exhaust can be used to bleed nitrogen to the cathode exhaust.

Abstract: A process for controlling the length of a purge and the purge rate of a fuel cell stack at system shut-down so as to provide the desired amount of stack humidity. The membrane humidification is measured at system shut-down by a high frequency resistance sensor that detects membrane humidification and provides the measurement to a controller. The controller controls the compressor that provides cathode input air to the fuel cell stack so that the time of the purge and the flow rate of the purge provide a desired membrane humidity for the next start-up.

Abstract: A set of fuel cell system heat exchangers that have been modified to incorporate thermal-to-electric devices is disclosed. These devices convert a portion of the thermal energy flowing through each heat exchanger to electric energy. Methods for operating the fuel cell system are also disclosed.

Abstract: A method for quickly and efficiently heating a fuel cell stack at system start-up. The method uses and prioritizes various stack heat sources based on their efficiency to heat the stack. A thermal set-point for heating the stack to the desired temperature is determined based on the ambient temperature and, the stack cooling fluid temperature. The set-point is then compared-to the stack heating provided by the heat sources that are operating through normal system start-up operation. If more heat is necessary to reach the set-point, the method may first charge a system battery using stack power where the load causes the fuel cell stack to heat up. If additional heating is still required, the method may then turn on a cooling fluid heater, then flow a small amount of hydrogen into the cathode inlet stream to provide combustion, and then increase the compressor load as needed.

Abstract: A heat exchanger design is provided for optimal transfer of thermal energy between a primary reactor-out reformate and a primary reactor-in steam and air. In particular, one embodiment of the present invention comprises a prime-surface true counter axial flow heat exchanger positioned around the primary reactor.

Abstract: A fuel processor for rapid start and operational control. The fuel processor includes a reformer, a shift reactor, and a preferential oxidation reactor for deriving hydrogen for use in creating electricity in a plurality of H2—O2 fuel cells. A heating and cooling mechanism is coupled to at least the shift reactor for controlling the critical temperature operation of the shift reactor without the need for a separate cooling loop. This heating and cooling mechanism produces or removes thermal energy as a product of the temperature of the combustion of air and fuel. Anode effluent and cathode effluent or air are used to control the temperature output of the heating mechanism. A vaporizer is provided that heats the PrOx reactor to operating temperature.

Abstract: A thermally-activated exhaust treatment device, such as a catalytic converter, for vehicles includes a core having an inner housing and a catalytic material. A jacket includes an outer housing enclosing the inner housing, but characteristically not contacting the inner housing. The inner and outer housings include walls forming a vacuum-drawn sealed insulation cavity around the inner housing. A temperature-activated variable insulator device is positioned within the outer housing and includes a hydrogen source and controls for controlling the variable insulator device. A vacuum-maintenance device is incorporated into the insulation cavity, and includes a small container, getter material positioned in the container, and a porous member allowing gas in the insulation cavity to communicate with the getter material. A multi-layered radiation shield is positioned in the vacuum space and is loosely coupled to the inner housing. A vacuum detector includes a visible indicator of the vacuum in the insulation cavity.

Abstract: A method and apparatus for thermal control of air flow in a fuel cell system, capable of accurately controlling the temperature of the air stream entering the water vapor transfer unit, maintaining a desired temperature set-point, and minimizing the time required for the air stream to reach the optimum operating temperature.

Abstract: A fuel cell system that employs a heat exchanger and a charge air cooler for reducing the temperature of the cathode inlet air to a fuel cell stack during certain system operating conditions so that the cathode inlet air is able to absorb more moisture in a water vapor transfer unit. The system can include a valve that selectively by-passes the heat exchanger if the cathode inlet air does not need to be cooled to meet the inlet humidity requirements. Alternately, the charge air cooler can be cooled by an ambient airflow.

Abstract: A method for starting a cold or frozen fuel cell stack as efficiently and quickly as possible in a vehicle application is based upon a state of charge of a first power source such as a high voltage battery. Power flow between the first power source and fuel cell system is coordinated in conjunction with a specific load schedule and parallel control algorithms to minimize the start time required and optimize system warm-up.

Abstract: A fuel cell system that employs a recuperative heat exchanger to provide additional cooling for the compressed charge air applied to the cathodes of the fuel cells in the fuel cell stack. The cathode exhaust gas is applied to the recuperative heat exchanger so that the cathode exhaust gas cools the charge air heated by the compressed air. A cathode exhaust gas expander is provided in combination with the recuperative heat exchanger that uses the energy in the heated cathode exhaust gas to power the charge air compressor. An anode exhaust gas combustor can be provided that burns residual hydrogen in the anode exhaust gas to further heat the cathode exhaust gas before it is applied to the expander.

Abstract: A compact cylindrical vaporizer for simultaneous reduction of a reformate stream temperature and generation of a process stream is disclosed. The vaporizer utilizes counter flowing nested tubular portions that spiral between an outer section of the vaporizer and a central section of the vaporizer. The return spiral has a larger cross-sectional area than the inward spiral to accommodate a higher volumetric flow rate of the water flowing there through as it vaporizes while keeping the fluid velocity below erosion design constraints. The counter spiraling flow provides a substantially uniform spatial temperature profile of a reformate stream flowing on the exterior of the tubular portions. The vaporizer can be sized to be substantially the same as that of an upstream reactor to minimize velocity losses and pressure drops in the reformate stream flowing there through. A plurality of fins are positioned between the opposing tubular portion to enhance the heat transfer.

Abstract: A thermally-activated exhaust treatment device, such as a catalytic converter (20); for vehicles includes a core having an inner housing (21) and a catalytic material (27, 27?). A jacket includes an outer housing (22) enclosing the inner housing (21) but characteristically not contacting the inner housing (21). The inner and outer housings (21, 22) includes walls (30, 31) forming a vacuum-drawn scaled insulation cavity (26) around the inner housing (21). A temperature-activated variable insulator device is positioned within the outer housing (22) and includes a hydrogen source (32) and controls for controlling the variable insulator device. A vacuum-maintenance device is incorporated into the insulation cavity (26), and includes a small container, getter material positioned in the container, a porous member allowing gas in the insulation cavity (26) to communicate with the getter material. A multi-layered radiation shield is position in the vacuum space and is loosely coupled to the inner housing (21).

Abstract: A heat exchanger design is provided for optimal transfer of thermal energy between a primary reactor-out reformate and a primary reactor-in steam and air. In particular, one embodiment of the present invention comprises a prime-surface true counterflow heat exchanger positioned around the primary reactor. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.72(b).

Abstract: A method for designing a fuel processor having an optimized size (i.e., volume and mass) for use in a fuel cell system which provides electrical power in a plurality of power ranges. The method includes maximizing water availability in the fuel cell system and sizing the first CO reduction reactor to provide for peak fuel cell system operational efficiency in a most-used power range while sizing the second CO reduction reactor to ensure the fuel processor can components to operate at a desired maximum power. The method allows development of a fuel processor that has significantly lower total mass and volume, and shorter start-up time, than conventionally designed processors, yet can perform at a desired maximum power.

Abstract: A thermally-activated exhaust treatment device, such as a catalytic converter (20) adapted to control exhaust emissions in a vehicle, includes a core having an inner housing (21) and a catalytic material (27) chosen to reduce undesirable emissions from the exhaust of a combustion engine. A jacket includes an outer housing (22) enclosing the inner housing (21) but characteristically not contacting the inner housing (21). The inner and outer housings (21, 22) include walls (30, 31) forming a vacuum-drawn sealed insulation cavity (26) around the inner housing (21). A chamber (60) positioned adjacent the inner housing (21) includes low melting point metal phase change material (61). A thermal management system is operably connected to the insulation cavity (26) that is constructed to control heat flow from the inner housing (21) to maximize the time the catalytic material (27) is within a predetermined optimum temperature operating range or limit catalyst maximum temperature.

Abstract: A fuel processor for rapid start and operational control. The fuel processor includes a reformer, a shift reactor, and a preferential oxidation reactor for deriving hydrogen for use in creating electricity in a plurality of H2—O2 fuel cells. A heating and cooling mechanism is coupled to at least the shift reactor for controlling the critical temperature operation of the shift reactor without the need for a separate cooling loop. This heating and cooling mechanism produces or removes thermal energy as a product of the temperature of the combustion of air and fuel. Anode effluent and cathode effluent or air are used to control the temperature output of the heating mechanism. A vaporizer is provided that heats the PrOx reactor to operating temperature.

Abstract: A heat exchanger design is provided for optimal transfer of thermal energy between a primary reactor-out reformate and a primary reactor-in steam and air. In particular, one embodiment of the present invention comprises a prime-surface true counterflow heat exchanger positioned around the primary reactor. It is emphasized that this abstract is provided to comply with the rules requiring an abstract, which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that is will not be used to interpret or limit the scope or meaning of the claims.

Abstract: An improved fuel processor thermal management system for use with a fuel cell is disclosed. The process includes supplying an air stream and a fuel stream into a auto thermal reactor (ATR) and forming reformate gas therein. Then, preferentially oxidizing the reformate gas and the air stream in the preferential oxidizer reactor (PrOx). The temperature of the preferential oxidizer reaction is controlled with a water stream by vaporizing the water stream to form a first portion of vaporized water. Then, reacting the air stream with the reformate gas exiting the PrOx is reached in a fuel cell to form an anode exhaust stream which is subsequently combined with the air stream to heat the water stream to form a second portion of vaporized water. The first portion of vaporized water and the second portion of vaporized water form a steam fluid.