Fuel cell system and method of controlling the same

A fuel cell system, comprising:

• a fuel cell that generates power by electrochemical reaction between anode gas and cathode gas;
• an exhaust pipe that has an exhaust port for discharging exhaust gas including the cathode gas and the anode gas discharged from the fuel cell;
• a cathode gas supply flow path that supplies the cathode gas to the fuel cell;
• a compressor that is provided in the cathode gas supply flow path to feed the cathode gas to the fuel cell;
• an anode gas detector that is provided outside a flow path of the anode gas to detect the anode gas;
• and
• a control unit configured to perform, when an exhaust port inundation condition is satisfied, prevention control for preventing the anode gas detector from detecting the anode gas as leakage of the anode gas, the prevention control includes a gas amount increase control for increasing a supply flow rate of the cathode gas to the exhaust pipe, as compared with a case without the prevention control, wherein
• the control unit is configured to determine the exhaust port inundation condition is satisfied when at least one of
• (i) a flow rate proportion, found by dividing a measured flow rate that is a flow rate of cathode gas introduced by the compressor by an assumed flow rate of the cathode gas estimated on a basis of an outside air pressure and a rotation speed of the compressor, is smaller than a predetermined flow rate proportion threshold,
• (ii) a pressure proportion, found by dividing a measured gas pressure that is a pressure at a cathode gas inlet or cathode gas outlet of the fuel cell by an assumed gas pressure estimated on the basis of the outside air pressure and the rotation speed of the compressor, is larger than a predetermined pressure proportion threshold, and
• (iii) a voltage proportion, found by dividing a measured voltage that is an outlet voltage of the fuel cell by an assumed voltage of the fuel cell estimated on the basis of a measured current that is an output current of the fuel cell and the rotation speed of the compressor, is smaller than a predetermined voltage proportion threshold,
• is satisfied.