Fuel cell system working to control supply pressure of fuel accurately

摘要

A fuel cell system is provided which includes an off-gas recirculating mechanism working to mix an off-gas discharged from a fuel cell with a hydrogen gas supplied to the fuel cell. The off-gas recirculating mechanism is implemented by an ejector vacuum pump which is controllable of an area of an outlet thereof to bring an output pressure into agreement with a target one. Use of such a type of ejector vacuum pump ensures desired accuracy of recircualtion of the off-gas and regulation of the pressure of fuel supplied to the fuel cell.