Patent ID: 7892682

Claim:
A method for controlling air-flow rate in a fuel cell system comprising: an electricity generation step in which hydrogen and air are supplied to a fuel cell for allowing a chemical reaction between the supplied hydrogen and air to generate electricity; a hydrogen dilution step in which hydrogen in a diluter discharged from the fuel cell is diluted with air discharged from the fuel cell; a request load air amount calculation step in which an amount of air required for generating electricity in the fuel cell which meets request load is calculated; a dilution air amount calculation step in which an amount of air to be supplied to the fuel cell that provides an amount of discharged gas required for diluting hydrogen discharged from the fuel cell to a specific concentration is calculated; and an air supply step in which air is supplied to the fuel cell based on the request load of the fuel cell decreasing, the air supply step: comparing the amount of air calculated in the request load air amount calculation step with the amount of air calculated in the dilution air amount calculation step, and selecting, as a result of the comparing, the larger of the amounts of air calculated in the request load air amount calculation step and the dilution air amount calculation step for supply to the fuel cell.