Abstract: A device is used to meter a gaseous medium, in particular air, by means of a plurality of metering valves, into a plurality of components of a fuel cell system used in a motor vehicle. All of the metering valves are arranged on a central middle block. The central middle block has at least one inlet opening for the gaseous medium, which is connected, via at least one passage, to in each case one connection point for each of the metering valves.

Abstract: A combined component consists of a heat exchanger and a reactor. The heat exchanger is designed in a plate form, and flow spaces for a first medium and a second medium are alternately defined between successive plates. The plates of the heat exchanger are configured as essentially annular. The heat exchanger has, substantially perpendicularly to the plates, a tubular outer wall and a tubular inner wall. The reactor is surrounded by the inner wall of the heat exchanger. The product of the reactor is conducted through supply orifices on the inner wall of the heat exchanger into the flow spaces for one of the two fluids in the heat exchanger.

Abstract: In a voltage measuring circuit for a composite fuel cell system, the potential of at least one point of the composite fuel cell system is detected by tapping the potential of such point, and feeding it to an input of an arrangement for evaluating the voltage. A potential shifting element is interposed between the at least one point of the composite fuel cell system and the input of the arrangement, which element is connected in series with a current sink or current source. A voltage supply circuit for such voltage measuring circuit of a composite fuel cell system comprising a plurality of individual fuel cells connected in series includes at least one voltage stabilization element connected in parallel with the circuit which is to be supplied with voltage by the composite fuel cell system. At least one current source or current sink is connected in series with this parallel circuit.

Abstract: A device for compensating for fluctuations in the concentration of a gaseous constituent in the fuel gas stream of a dynamically operated fuel cell system, has a buffer component arranged in the fuel gas stream, provided downstream of a component of the fuel cell system which is to be protected. The buffer component takes up the gaseous constituent from the fuel gas stream in the event of the partial pressure rising and releases the gaseous constituent back into the fuel gas stream in the event of the partial pressure dropping. According to the invention, the buffer component contains a material for the adsorption or absorption of the gaseous constituent that has a take-up capacity which is dependent on the partial pressure.

Abstract: A fuel cell system includes a fuel cell with a cathode space and an anode space that are separated by a polymer electrolyte membrane. The cathode space is supplied with an oxygen-containing gas, and the anode space is supplied with a hydrogen-containing gas. A gas-generation device is provided in which a hydrogen-rich reformate containing carbon monoxide, is produced from a fuel with the aid of steam reforming and/or partial oxidation. A gas-cleaning stage selectively oxidizes the carbon monoxide in the reformate on a suitable catalyst while oxygen is added; and a heat exchanger which is arranged in the gas-cleaning stage, has a cooling medium flowing through it and serves to dissipate thermal energy. According to the invention, to dissipate the thermal energy, the anode off-gas and/or cathode off-gas emerging from the fuel cell and/or a starting-material gas which is present in the fuel cell system flows through the heat exchanger.

Abstract: In a process for operating a fuel cell system with a water balance, a hydrogen-containing medium or a mixture of mediums is reformed in a reforming reactor with a water requirement, by adding water to a hydrogen rich reformate. The reformate is fed to an anode region of a fuel cell and reacts with oxygen from a cathode region of the fuel cell, forming water in the fuel cell. The the water required for the reforming reaction and/or the water balance of the fuel cell system is coupled directly to the oxidation rate of the partial combustion of the hydrogen-containing medium or the mixture of mediums in an oxidizing unit upstream of the reforming reactor.

Abstract: A fuel cell system comprises a fuel cell having an anode and a cathode, a fuel feed line connected to the anode, an oxidant feed line connected to the cathode and a cathode exhaust line. A water collecting unit is connected to the cathode exhaust line, and a cooling circuit comprising a radiator is configured to cool the fuel cell. A nozzle is connected to the water collecting unit and configured to spray water onto the radiator.

Abstract: A fuel cell system comprises a fuel cell unit and facility for humidifying process gases to provide a fuel for the fuel cell unit, wherein water-carrying media conduits of the fuel cell unit are provided at least in part as heatable media conduits.

Abstract: A vehicle includes a traction unit for delivering mechanical power from a combustion engine to a vehicle drive shaft and driving wheels, electric loads and a vehicle cooling loop for cooling vehicle components and/or said combustion engine. A fuel cell system, which supplies the electric loads with electric power, includes a fuel cell stack, an anode fuel input, a anode exhaust, a cathode fuel input, a cathode exhaust, and a fuel cell cooling loop for cooling the fuel cell stack via an input line which delivers a cooling medium into the fuel cell stack and an output line which removes the heated cooling medium from the fuel cell stack. A compression/expansion unit is provided between the output line of the fuel cell stack and the vehicle cooling loop. The expansion side of the compression/expansion unit in thermal contact with the heated cooling medium, which is at a first temperature level, so that heat is transferred from the heated cooling medium to the expansion side of the compression/expansion unit.

Abstract: A motor vehicle has a drive combustion engine and a power supply system for supplying electric consuming devices on-board the motor vehicle. The power supply system includes a fuel cell system and a battery coupled to the fuel cell system. The energy and/or material currents of the drive combustion engine and the fuel cell system are coupled together.

Abstract: An apparatus for generating and distributing electrical power in a vehicle which has at least one electric drive motor connected via a converter to a fuel cell unit, with the fuel cell unit being connected to at least one first, one second and one third voltage network, and with each voltage network having at least one associated electrical load and/or at least one associated energy store. The first voltage network is formed by the fuel cell voltage network and is connected via a first bidirectional DC/DC converter to the second voltage network and the first bidirectional DC/DC converter provides DC isolation between the first voltage network and the second voltage network. The second voltage network is connected via a second bidirectional converter to the third voltage network.

Abstract: A fuel cell section system has a media-cooled fuel cell with an anode space and a cathode space. A common delivery device is provided for introducing cooling medium into both the fuel cell and a condenser for condensation of water from outgoing cathode air.

Abstract: A circuit arrangement for supplying electrical energy to a power supply has a fuel cell and an accumulator arrangement. Electrical energy is delivered by the accumulator arrangement during the starting procedure, and is fed into the power supply by the accumulator arrangement via at least one DC/DC converter during starting of the circuit arrangement.

Abstract: A vehicle includes a traction unit capable of delivering mechanical power for driving the vehicle; electric loads; and a fuel cell system for supplying the electric loads with electric power. The fuel cell system includes a fuel cell stack with an anode input line, an anode exhaust line, a cathode input line, and an cathode exhaust line. A compression/expansion loop is employed in the cathode exhaust line. The expansion side of the compression/expansion loop is in thermal contact with the cathode exhaust to cool the cathode exhaust and to transfer the heat of the exhaust to the compression side of the compression/expansion loop at a higher temperature level. A water separator is arranged in the cathode exhaust line for collecting water vapor of product water that is carried in the cathode exhaust and is recycled to the fuel cell system.

Abstract: A fuel cell system and method for operating a fuel cell system have a water separator for extracting water contained in a fuel cell exhaust stream. The method comprises varying the pressure of the fuel cell exhaust stream in response to a change in ambient temperature in the vicinity of the fuel cell system. The pressure can be varied by the use of a flow control device positioned downstream of the fuel cell and operationally linked to an ambient temperature sensor.

Abstract: A starter device, preferably for cold-starting, for fuel cell systems, including a current generation system, for generating electrical energy, and a gas generation system, for generating H2-rich gas for the current generation system. An internal-combustion engine generates mechanical energy, which can be connected to an air compressor for supplying air to the gas generation system via a drive shaft.

Abstract: A fuel cell system, which may include a fuel processing subsystem for converting hydrocarbons into a hydrogen-rich gas, is designed so that at least some of the components of the fuel cell system are contained inside at least one housing. The housing contains a recombiner to convert hydrogen and oxygen into water. The housing may also contain a temperature sensor in the vicinity of the recombiner.

Abstract: A fuel cell system comprises a plurality of fuel cells arranged in a stack between two end plates. An electrical load is connected to the fuel cell stack via a load circuit, and a diode is arranged between the fuel cell stack and the electrical load in the load circuit. According to the invention, the diode is arranged directly on or in one of the end plates. Moreover, a cooling device, which is in thermal contact with the diode and dissipates the power loss from the diode, is provided in the region of the diode.

Abstract: A method and apparatus are provided for operating a fuel cell system. The method and apparatus can provide electrical power to a motor vehicle, the motor vehicle comprising a fuel cell, an electrical propulsion unit that is powered at least partially by the fuel cell, and a compressor to provide oxidant for the fuel cell. A target power demand may be determined based on an accelerator pedal demand. The power difference between the target power demand and the instantaneous power that is available from the fuel cell is compensated by power originating from an electrical energy storage device. Immediately after an increase in accelerator pedal demand, the electrical energy storage device first provides electrical power to drive the oxidant compressor, until a certain increase in the power available from the fuel cell has been detected. Once such an increase has been detected, the electrical energy storage device provides power to the electrical propulsion unit, such as a traction motor.

Abstract: A fuel cell system and associated method allows for continuous operation of the fuel cell system with fuel recirculation, without the necessity for periodic purging. A portion of the anode exhaust is not recirculated but is continuously bled from the anode exhaust line. Preferably, less than 5% by volume of the anode exhaust is allowed to bleed continuously from the anode exhaust. The bleed line may be connected to a catalytic reactor which combusts the unused fuel. The cathode exhaust may be used as the oxidant for the catalytic reactor. The flow of exhaust to the catalytic reactor may be controlled to ensure that the concentration of hydrogen in the catalytic reactor is no higher than 50% of the lower limit of inflammability for hydrogen.