Patent ID: 9559371
Date: 2017-01-31
CPC Classifications: C01B,H01M,Y02E

Claim:
1. A fuel cell system comprising: a fuel cell that is supplied with an anode gas and a cathode gas to generate electricity; an evaporation unit that evaporates reforming water to generate water vapor; a reforming unit that reforms a raw material gas using the water vapor generated in the evaporation unit by a reforming reaction to form the anode gas; a water tank that stores the reforming water before being supplied to the evaporation unit; a water supply passage that allows the water tank and the evaporation unit to communicate with each other to supply the reforming water in the water tank to the evaporation unit; a water pump that supplies the reforming water in the water tank to the evaporation unit; a rotational speed sensor that detects number of rotations per unit time of the water pump based on a physical quantity concerning the rotational speed of the water pump; and a control unit that is programmed to input a detection signal of the rotational speed sensor and to control the water pump, the control unit is programmed to presume an influence that is caused by resonance of the water pump when the rotational speed of the water pump is abnormal or is expected to be abnormal with respect to a target rotational speed region during the power generation operation of the fuel cell, and to execute an S/C value averaging control that alternately repeats an increase in a short time (ΔT increase, within 10 seconds) and a decrease in a short time (ΔT decrease, within 10 seconds) of the rotational speed of the water pump with respect to the abnormal rotational speed while continuing the power generation operation of the fuel cell, and repeats the short time increase and the short time decrease of the rotational speed of the water pump and thus a short time increase and the short time decrease of an S/C value in the reforming reaction, thereby averaging the S/C value which is directly correlated to the rotational speed of the water pump, wherein the S/C value is a molar ratio of water vapor to a carbon component contained in the raw material gas.