Patent ID: 8268501

Claim:
A fuel cell system in which an amount of gas to be supplied to a fuel cell is limited to perform a low-efficiency operation, comprising: a fuel cell; a fuel gas supply system for supplying a fuel gas to the fuel cell; an oxidizing gas supply system for supplying an oxidizing gas to the fuel cell; and a control unit programmed to perform the low-efficiency operation, the control unit further comprising: a produced water amount detection device that detects an amount of water produced in the fuel cell during the low-efficiency operation; and a gas supply limitation device that limits an amount of gas to be supplied to the fuel cell, based on the detected amount of water, wherein the produced water amount detection device is programmed to calculate the amount of water based on an integrated amount of an output current of the fuel cell from a start of the low-efficiency operation, and wherein the gas supply limitation device is programmed to calculate an estimated output current of the fuel cell at a predetermined time later based on an output voltage of the fuel cell, a temperature of the fuel cell, and the calculated amount of water, and is programmed to estimate the amount of gas to be supplied to the fuel cell based on the calculated, estimated output current of the fuel cell at the predetermined time later.