Abstract: A coolant pump includes a conveying channel, a drive shaft, a coolant pump impeller arranged on the drive shaft, a control slide which controls a flow cross-section of an annular gap between an exit of the coolant pump impeller and the conveying channel, a side channel pump which includes a side channel pump impeller arranged on the drive shaft and a side channel having an inlet and an outlet where a pressure can be generated by the side channel pump impeller rotating, a pressure channel having a flow cross section which fluidically connects the outlet to a first pressure chamber of the control slide, a valve which closes the flow cross-section, a second pressure chamber arranged on a side of the control slide facing the coolant pump impeller, and a connection channel arranged from the side channel into the second pressure chamber between the inlet and the outlet.

Abstract: A coolant pump includes a conveying channel, a drive shaft, a coolant pump impeller arranged on the drive shaft, a control slide which controls a flow cross-section of an annular gap between an exit of the coolant pump impeller and the conveying channel, a side channel pump which includes a side channel pump impeller arranged on the drive shaft and a side channel having an inlet and an outlet where a pressure can be generated by the side channel pump impeller rotating, a pressure channel having a flow cross section which fluidically connects the outlet to a first pressure chamber of the control slide, a valve which closes the flow cross-section, a second pressure chamber arranged on a side of the control slide facing the coolant pump impeller, and a connection channel arranged from the side channel into the second pressure chamber between the inlet and the outlet.

Abstract: An anode gas circuit of a fuel cell system. The anode gas circuit includes a return line leading from an anode gas outlet of a fuel cell stack to an anode gas inlet of the fuel cell stack, a recirculation blower disposed in the return line, a first valve disposed in the return line upstream of the recirculation blower, and a second valve disposed in the return line downstream of the recirculation blower. The first valve and the second valve are configured to close a cross section of the return line.