Patent ID: 7875398

Claim:
A fuel cell system, comprising: a fuel cell configured to be fed with a reaction gas and generate electric power at a predetermined required output power; a reaction gas supply system configured to feed the reaction gas to the fuel cell at a feed rate; an output detection unit configured to detect an output current and an output voltage of the fuel cell; a storage unit which stores a standard current-voltage characteristic of the fuel cell, from which a standard voltage of the fuel cell at a given output current thereof is obtainable; a gas feed mismatch detection unit configured to detect a gas feed mismatch of the reaction gas, based on a comparison between the output voltage of the fuel cell detected by the output detection unit, and the standard voltage at the output current detected by the output detection unit, obtained from the standard current-voltage characteristic stored in the storage unit; and a gas feed control unit configured to control the gas feed of the reaction gas supply system, wherein the gas feed control unit is configured to change the feed rate of the reaction gas from a first feed rate to a second feed rate, according to a result of the comparison between the standard voltage and the detected output voltage, when the gas feed mismatch of the reaction gas is detected by the gas feed mismatch detection unit, wherein the first feed rate is determined as a first function of a product of the predetermined required output power and a first control stoichiometric ratio, and the second feed rate is determined as a second function of a product of the predetermined required output power and a second control stoichiometric ratio, and wherein the gas feed control unit is configured to change the feed rate from the first feed rate to the second feed rate under a condition that the power generated by the fuel cell fed with the reaction gas at the first feed rate and the power generated by the fuel cell fed with the reaction gas at the second feed rate are maintained at the predetermined required output power.