Abstract: In certain configurations and applications, fuel cell stacks can be subject to damage arising from resonance. For instance, the natural frequency of lengthy automotive fuel cell stacks can be low enough to be problematic. Incorporating appropriate support bars between the compression straps holding such stacks together and the fuel cells in the stack can suitably increase the natural frequency in a relatively compact manner.

Abstract: In certain configurations and applications, fuel cell stacks can be subject to damage arising from resonance. For instance, the natural frequency of lengthy automotive fuel cell stacks can be low enough to be problematic. Incorporating appropriate support bars between the compression straps holding such stacks together and the fuel cells in the stack can suitably increase the natural frequency in a relatively compact manner.

Abstract: A Coanda flow amplifier has a suction intake, an outlet, a fluid channel extending between the suction intake and the outlet, and a drive-flow inlet, which is fluidly connected to the fluid channel via a drive-flow discharge slit, whereby the flow cross section of the drive-flow discharge slit is variably adjustable. In a method to operate the Coanda flow amplifier, the variably adjustable flow cross section of the drive-flow discharge slit is chosen such that a pressure ratio between an output pressure of the drive flow when it leaves the drive-flow discharge slit, and an intake pressure of the drive flow when it enters the drive-flow discharge slit, does not exceed a critical pressure ratio. A fuel cell system comprises at least one fuel cell, a fluid source, a fluid line, and a Coanda flow amplifier arranged in the fluid line, whereby the Coanda flow amplifier is equipped with a drive-flow discharge slit with a variably adjustable flow cross section.

Abstract: A Coanda flow amplifier has a suction intake, an outlet, a fluid channel extending between the suction intake and the outlet, and a drive-flow inlet, which is fluidly connected to the fluid channel via a drive-flow discharge slit, whereby the flow cross section of the drive-flow discharge slit is variably adjustable. In a method to operate the Coanda flow amplifier, the variably adjustable flow cross section of the drive-flow discharge slit is chosen such that a pressure ratio between an output pressure of the drive flow when it leaves the drive-flow discharge slit, and an intake pressure of the drive flow when it enters the drive-flow discharge slit, does not exceed a critical pressure ratio. A fuel cell system comprises at least one fuel cell, a fluid source, a fluid line, and a Coanda flow amplifier arranged in the fluid line, whereby the Coanda flow amplifier is equipped with a drive-flow discharge slit with a variably adjustable flow cross section.

Abstract: A fuel cell system comprising a fuel cell which contains an anode and a cathode, further comprising a cathode compressor to supply process air to the fuel cell, and an anode compressor to supply fuel gas to the fuel cell, whereby the cathode compressor and the anode compressor can be driven by a common motor drive, and whereby an automatic clutch is provided to couple and decouple the driving of the cathode compressor and the anode compressor.

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 fuel cell system includes at least one fuel cell unit which is accommodated in a fuel cell enclosure. A cathode gas delivery line, cold-start gas delivery line, a cathode off-gas return line, anode off-gas return line may also be provided. According to the invention, the system is equipped with at least one Coanda flow amplifier in order to amplify the air stream for the purpose of ventilating the fuel cell enclosure, a cathode gas stream, a cold-start gas stream, a recirculated cathode off-gas stream or a recirculated anode off-gas stream. The may be equipped with a ventilating means for a housing outside the fuel cell enclosure. In the housing are components of the fuel cell system, said ventilating means including a Coanda flow amplifier.

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 flow body has a wall and a flow channel inside the wall for a fluid. The flow channel has in an entry region of the fluid into the flow body in the direction of flow, along a central axis, a first region with a convergent cross-sectional profile. Adjoining the first region is a second region with a divergent cross-sectional profile. The flow body is made up along its axis of at least a first segment and a second segment, the first segment having a convergent cross-sectional profile and the second segment having a divergent cross-sectional profile. The segments are connected together at abutting surfaces.

Abstract: A fuel cell system includes at least one fuel cell unit which is accommodated in a fuel cell enclosure. A cathode gas delivery line, cold-start gas delivery line, a cathode off-gas return line, anode off-gas return line may also be provided. According to the invention, the system is equipped with at least one Coanda flow amplifier in order to amplify the air stream for the purpose of ventilating the fuel cell enclosure, a cathode gas stream, a cold-start gas stream, a recirculated cathode off-gas stream or a recirculated anode off-gas stream. The may be equipped with a ventilating means for a housing outside the fuel cell enclosure. In the housing are components of the fuel cell system, said ventilating means including a Coanda flow amplifier.

Abstract: A valve with a Laval nozzle, a valve needle movable axially in the Laval nozzle, and an inlet chamber which receives the valve needle foot, in which chamber a radially extended inlet opening terminates. The inlet chamber is separated axially from the inlet plane of the Laval nozzle by a flow channel located therebetween. The inlet chamber is delimited by the valve needle on one side and by one of the valve needle housing sections surrounding the valve needle on the other side. This valve can be used in particular as a metering valve for metering a process gas for a reaction process in a motor vehicle operated by a fuel cell.