Fuel cell system and gas leakage detection device

Abstract

A fuel cell system according to one aspect of the invention is operated in an ordinary mode and in a gas leakage detection mode. The fuel cell system includes fuel cells, a fuel gas supplier configured to supply a fuel gas to the fuel cells, a shutoff valve provided in a flow path for leading a flow of the fuel gas supply from the fuel gas supplier to the fuel cells and configured to shut off the fuel gas supply, and a variable pressure regulator provided in the flow path between the shutoff valve and the fuel cells to regulate a pressure of the fuel gas in a downstream in a flow direction of the fuel gas supply to a variable pressure value. In the ordinary mode, the fuel cell system sets the pressure value of the variable pressure regulator to an ordinary power generation pressure value for ordinary power generation. In the gas leakage detection mode, on the other hand, the fuel cell system closes the shutoff valve, sets the pressure value of the variable pressure regulator to a higher value than the ordinary power generation pressure value, and performs leakage detection of the fuel gas from the shutoff valve. Such setting of the pressure value in the variable pressure regulator desirably enables high-speed reduction of the fuel gas pressure in the flow path between the shutoff valve and the variable pressure regulator.