Bayerische Motoren Werke Aktiengesellschaft

Marcel Sterzenbach

Stefan Haase

Marco Schwarze

An exhaust air guide of a fuel cell stack is provided, in particular in a motor vehicle, with a cooling device which belongs to the functional environment of the fuel cell stack and is in the form of a cooler structure through which ambient air flows. At least some of the exhaust air of the fuel cell stack is guided into the cooler structure or behind the cooler structure, as viewed in the direction of flow of the ambient air through the cooler structure, to such an extent that, at the cooler structure, the exhaust air flow brings about an increase in the mass flow of the ambient air through the cooler structure in accordance with the jet pump principle or, at the cooler structure, the exhaust air flow, in accordance with the jet pump principle, brings about a pressure difference conveying at least a portion of the ambient air through the cooler structure.

Exhaust air guide of a fuel cell stack in a motor vehicle

An operating method is provided for a fuel cell system with a radiator structure which is flowed through by ambient air and a fuel cell stack, at least part of the outgoing air flow of the fuel cell stack can be guided onto the radiator structure such that, at the radiator structure, the guided outgoing air flow causes an increase in mass flow of the ambient air through the radiator structure according to the jet pump principle. At least part of the outgoing air flow of the fuel cell stack can be guided through a gas expansion machine. The division of energy which is contained in the outgoing air flow and can be recovered in the gas expansion machine and/or at the radiator structure according to the jet pump principle is changed by an electronic control unit in a manner which is adapted to boundary conditions. This division is set and changed, in particular, using the temperature of the medium to be cooled in the radiator structure and the required electrical power of the fuel cell stack, by the pressure drop in the gas expansion machine being set by targeted setting of the flow conditions prevailing therein and/or the magnitude of the outgoing air flow which is guided through the gas expansion machine being set via a controllable bypass of the gas expansion machine.

Growing community of inventors

Landshut, Germany

Marcel Sterzenbach