Patent ID: 8563191

Claim:
A fuel cell system equipped with fuel cells, the fuel cell system being operated at least in a gas leakage detection mode for detection of a leakage of a fuel gas, the fuel cell system comprising: a fuel gas supplier configured to supply the 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; 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; a high pressure regulator provided in an upstream of the variable pressure regulator on the flow path in the flow direction of the fuel gas supply to regulate the pressure of the fuel gas supply to a preset pressure value, a first pressure sensor configured to measure a pressure between the variable pressure regulator and the high pressure regulator on the flow path; a shutoff valve controller configured to close the shutoff valve in the gas leakage detection mode; a variable pressure regulator controller configured to set the pressure value of the variable pressure regulator to a higher value than a previous pressure value prior to setting of the gas leakage detection mode, after closure of the shutoff valve; and a gas leakage detector configured to perform leakage detection of the fuel gas from the shutoff valve with reference to the pressure measured by the first pressure sensor, after setting of the higher pressure value in the variable pressure regulator; wherein when the pressure measured by the first pressure sensor decreases below the preset pressure value regulated by the high pressure regulator, the gas leakage detector is programmed to perform the leakage detection of the fuel gas from the shutoff valve with reference to the pressure measured by the first pressure sensor.