Patent ID: 8628888

Claim:
A fuel cell system comprising: a fuel cell that generates electricity by causing reaction between fuel gas and oxidant gas; an air compressor that supplies air, used as the oxidant gas, to the fuel cell; a shut-off valve that interrupts air, which is exhaust gas exhausted from the fuel cell, from being exhausted outside; an air flow meter that measures the flow rate of air supplied to the fuel cell; a pressure sensor that measures at least a pressure of the supplied air; and a control unit programmed to control power generation reaction of the fuel cell, the control unit being programmed i) to operate the air compressor for a predetermined period of time in a state where the shut-off valve is closed, and to record a value measured by the air flow meter and a value measured by the pressure sensor during then, ii) to calculate: a first calculated air flow rate based on the value measured by the air flow meter by integrating the value measured by the air flow meter by the predetermined period of time, iii) to calculate a second calculated air flow rate based on a system volume from the air compressor to the shut-off valve, a pressure increase of air in the system volume, calculated on the basis of the value measured by the pressure sensor, and an atmospheric pressure, and then iv) to calculate a ratio of the second calculated air flow rate to the first calculated air flow rate.