Abstract: A plurality of catalyst disks pressed from porous catalyst material are stacked one on the other and together sintered with the application of pressure to make a stacked reactor for hydrogen production from hydrocarbons. To form especially tight seams the catalyst disks have projections formed in the area of contact with an adjacent catalyst disk. Hollow spaces formed in the catalyst disk or formed by two adjacent catalyst disks have a system for supporting the hollow spaces, as for example a cooper grid placed in the hollow space, which can be covered at least partially by a metal sheet or supporting bars pressed onto the catalyst disk.

Abstract: A device for the production of hydrogen-containing gas for a fuel cell system, in particular in a motor vehicle, is disclosed. Suitable feed materials are water and at least one hydrocarbon-containing starting material, in particular a hydrocarbon derivative, such as methanol or ethanol. The device comprises an evaporator to evaporate the feed material; a superheater to superheat the feed material vapor; a high temperature reformer in which steam reforming of the superheated feed material is carried out; a burner which provides the thermal energy required for the steam reforming by burning a gas stream that contains fuel and oxygen; a water gas shift stage to reduce the carbon monoxide content of the reformate stream produced in the steam reforming; and a cooler to reduce the temperature of the reformate stream between the point where the reformate stream is discharged out of the high temperature reformer and the point where the reformate stream enters into the water gas shift stage.

Abstract: A respective bipolar junction transistor is coupled across pairs of fuel cells in a fuel cell stack to monitor the voltage across each fuel cell pairs for a drop in voltage below a threshold voltage. A respective optoisolator coupled to each of the transistors produces a digital signal corresponding to the status of the respective pair of fuel cells. An “AND” circuit produces a single digital signal corresponding to the status of one or more pairs of fuel cells.

Abstract: A fuel cell system includes fuel cells forming a fuel cell stack, having a fuel passage and an oxidant passage. A purge valve is coupled to the fuel passage to exhaust contaminants, and a controller is coupled to temporarily increase the oxidant stream flow rate through the oxidant passage, and to temporarily open the fuel purge valve, if a voltage across a pair of fuel cells is less than a defined threshold voltage. In this resuscitation step, the oxidant flow rate can be temporarily increased by increasing a duty cycle of an air compressor by approximately 50% for a duration of between approximately 5 to 10 seconds. The controller can further shut down fuel cell operation if a voltage across a pair of fuel cells is less than a defined threshold voltage in an inter-resuscitation period immediately following the resuscitation step.

Abstract: An electric power generating system is provided that comprises a fuel cell stack having at least one solid polymer fuel cell, a cooling system having a coolant flow path that directs coolant to and from the stack, a fuel regulating system having a fuel flow path and for regulating the supply of fuel from a fuel supply to the stack via the fuel flow path, and a hydrogen concentration sensor. The sensor is located in the vicinity of the fuel regulating system and in the coolant flow path at a location downstream of the stack to detect hydrogen that may have been discharged by components of the power generating system in the coolant flow path upstream of the sensor, or by the fuel regulating system. In the event the measured hydrogen concentration exceeds a threshold level, steps are taken to reduce or stop the discharge of hydrogen from the power generating system.

Abstract: A fuel cell system includes a fuel cell stack, a battery, and a control system. A power circuit couples the fuel cell system selectively between the fuel cell stack and the battery. The power circuit includes a battery supply switch responsive to a voltage across the fuel cell stack, and a stack supply switch responsive to an operating state of the fuel cell system. The battery supply switch uncouples the battery from an on-board power supply when a voltage across the fuel cell stack exceeds a first threshold voltage and couples the battery to the on-board power supply when the fuel cell stack voltage is less than a second threshold voltage. The stack supply switch couples power the fuel cell stack to the on-board power supply when in a running state. A diode-OR circuit couples the source with the highest potential to the on-board power supply.

Abstract: A reactor is provided for the catalytic conversion of a mixture of a reactants, such as fuel, into at least one reaction product, the reactor having a reaction chamber containing at least one catalytically active substance for the conversion. The reactor chamber further has a reaction area that at start-up is not yet reactive at ambient temperature, and an ignition area that is already capable of ignition at ambient temperature. Ignition area is in only partial contact with reaction area, and the ignition area is porous and contains one or more noble metals. The thermal contact between the two different areas is such that the heat output dissipated from the ignition area at ambient temperature is less than the heat output generated in this area.

Abstract: An electrochemical power generation system includes a fuel cell stack having an oxidant delivery system for delivering air from the ambient environment to the oxidant inlet of the stack, an oxygen sensor for measuring the oxygen concentration of ambient air in the vicinity of the power generation system. A controller coupled to the oxygen sensor is configured to cease operation of the power generation system when the oxygen concentration of the ambient air in the vicinity of the power generation system falls below an oxygen concentration threshold. The power generation system may also include a purge valve associated with a fuel outlet from the stack.

Abstract: A purge system for fuel cell stack includes a purge valve to regulate exhaust from the fuel cell stack in response control signals from a controller in response to a voltage across a purge cell portion of a fuel cell stack. The purge valve is opened when the voltage across the purge cell portion falls below a defined percentage of a threshold voltage. The threshold voltage can be equal to an average cell voltage of some or all of the fuel cells of the fuel cell stack. The purge may include one or more successive openings of the purge valve of controlled purge durations.

Abstract: A controller in a fuel cell system performs various operating parameter checks at a predefined schedule, including one or more of a stack current check; a stack voltage check; a cell voltage check; a purge cell check; an oxygen concentration check; a hydrogen concentration check; a stack temperature check; an ambient air temperature check; a fuel pressure check; and an airflow rate check; a hydrogen sensor heater check; a battery voltage check; a microcontroller self-check; and/or toggling a watchdog. The frequency of the checks are set relative to achieve an efficient control of the fuel cell system by selectively distributing the load on the microcontroller.

Abstract: A microcontroller in a fuel cell system performs at least a portion of a self-test of general registers while the system is in a starting state, and at least a portion of a self-test while in a running state. The self-test includes setting the general purpose registers to a first bit pattern, complementing the bits of one of the general registers, copying the complemented general register to a special register, determining if each bit in special register was complemented, and producing a notification. The microcontroller also verifies that the other general registers are not affected. The microcontroller again complements the previously complemented general purpose register, copies the complemented general register to the special register, determines if the special register matches the predefined pattern, and produces a notification. The microcontroller again verifies that the other general purpose registers were not affected.

Abstract: An electric power generation system includes a fuel cell stack and a product water pumping system from the stack to pump product water away from the power generation system. A reactant exhaust chamber is coupled to a product water pumping chamber by a drain, and a valve controls the flow of water through the drain. An oxidant exhaust inlet provides an oxidant exhaust flow to the reactant exhaust chamber from the stack, while an oxidant exhaust outlet discharges oxidant exhaust from the reactant exhaust chamber. A pump fluid inlet provides a pump fluid flow to product water pumping chamber from the stack to pump collected product water out of the product water pumping chamber via a product water outlet. The pump fluid flow can take the form of a fuel stream or by a purge discharge containing fuel.

Abstract: A heat exchanger has a plurality of fluidically parallel first layers which define first heat exchanger ducts through which a first medium is capable of flowing, and in each case has a second layer between the two first layers. The respective second layer is in thermal contact with the two adjacent first layers and defines at least one second heat exchanger duct through which a second medium is capable of flowing in parallel. The respective second layer comprises two fluidically parallel layer plies. A controllable supply of the second medium to the one and/or the other layer ply in each case is provided. Such a heat exchanger can be used, in particular, as an evaporator with an integrated starting and main evaporator part, and particularly as an evaporator in a reforming plant of a fuel-cell vehicle.

Abstract: A pressure regulator for a fuel cell unit includes a membrane that separates the pressure regulator into an anode-side region and a cathode-side region. The membrane is acted in the anode-side region by the pressure of the anode side of the fuel cell unit and in the cathode-side region by the pressure of the cathode side of the fuel cell unit. The pressure regulator further includes an actuator connected to the membrane, wherein the actuator sets a predetermined pressure on at least one of the anode and cathode sides.

Abstract: The activity of catalysts used in promoting the oxidation of certain oxidizable species in fluids can be enhanced via electrochemical methods, e.g., NEMCA. In particular, the activity of catalysts used in the selective oxidation of carbon monoxide can be enhanced. A purification system that exploits this effect is useful in purifying reformate supplied as fuel to a solid polymer electrolyte fuel cell stack. The purification system comprises an electrolytic cell with fluid diffusion electrodes. The activity of catalyst incorporated in the cell anode is enhanced.

Abstract: Method for manufacturing a metal foil consisting of several metals in which at least one galvanic bath of several different bath types is prepared. Each bath type contains an electrolyte solution suitable for the deposition of one of the metals involved. A layer stack is then formed for the metal foil by successive alternate galvanic deposition of one layer at a time of the metals contained in the various bath types, on the circumference of a rotating deposition roller which is wired as a cathode in the corresponding galvanic bath. This step is followed by a tempering process that converts the layer stack is converted into a homogeneous alloy of the metals. Thereby, a metal membrane foil is produced for hydrogen separation from a process gas of a methanol reformation system in a fuel-cell-operated motor vehicle.

Abstract: A self-inerting fuel processing system is provided. In one embodiment, the present fuel processing system comprises a fuel processor comprising a reformer, at least one self-reducing catalyst bed, a recycle loop for circulating a gas stream through the fuel processor and the self-reducing catalyst bed(s) during shutdown of the fuel processing system, and an oxidant supply for introducing oxidant into the recycle loop during shutdown of the fuel processing system. A method for shutting down the fuel processing system is provided. A fuel cell electric power generation system incorporating the present fuel processing system is also provided.

Abstract: A method and apparatus for controlling a permanent magnet synchronous motor (8) coupled to a turbo engine such that transient current and steady state current are minimized. The method comprises the steps of, for a given DC bus voltage, determining an acceleration profile as a function of a voltage-offset value, a low-speed rated speed value, a high-speed rated speed value, a first desired speed for warming up the turbo engine, and a second desired speed where the turbo engine has sufficient torque to accelerate to its rated speed without the aid of the permanent magnet synchronous motor (8).

Abstract: The electrocatalysts in certain fuel cell systems can be poisoned by impurities in the fuel stream directed to the fuel cell anodes. Introducing a variable concentration of oxygen into the impure fuel stream supplied to the fuel cells can reduce or prevent poisoning without excessive use of oxygen. The variation may be controlled based on the voltage of a carbon monoxide sensitive sensor cell incorporated in the system. Further, the variation in oxygen concentration may be periodic or pulsed. A variable air bleed method is particularly suitable for use in solid polymer fuel cell systems operating on fuel streams containing carbon monoxide.

Abstract: Stripped porous polymer film and a method for making such film from substantially heterogeneous porous polymer film are described. The heterogeneous film has surface characteristics that are different from the characteristics of the interior bulk material, and the method comprises mechanically stripping at least a portion of at least one surface layer from the heterogeneous film. The stripped porous polymer film may be incorporated into composite membranes. Such composite membranes are particularly suitable for incorporation into membrane electrode assemblies for use in electrochemical cells, including electrochemical fuel cells.