Patent ID: 7297427

Claim:
A process for controlling a fuel cell system comprising a fuel cell, which generates power by reacting anode gas and cathode gas supplied to the fuel cell, a compressor which varies a rotation number thereof to thereby control an amount of the cathode gas to be supplied to the fuel cell, and a pressure control valve which varies an opening thereof to thereby control a pressure of the cathode gas, wherein the pressure control valve is provided downstream of a cathode of the fuel cell, said process comprising: first controlling said compressor to change an amount of the cathode gas supplied to the fuel cell at a start of a transition period of said fuel cell, and thereafter changing an opening of said pressure control valve, depending on the changed amount of the cathode gas, to thereby regulate the pressure of the cathode gas, wherein an amount of power generated from the fuel cell is changed during the transition period, wherein the opening of the pressure control valve for controlling the pressure of the cathode gas is decreased during a first period of the transition period, and thereafter the opening of the pressure control valve is increased following an increase of the cathode gas flow amount.