Patent ID: 7300717

Claim:
A control device for a fuel cell system having a fuel cell stack with an oxidizing electrode supplied with oxidizing gas and a fuel electrode supplied with fuel gas to generate an electric power, the control device comprising: an estimating section estimating occurrence of a water-clogging phenomenon wherein condensed water stays in a fuel gas flow passage through which fuel gas is supplied to a fuel electrode of the fuel cell stack; a control section controlling a fuel gas exhaust valve, which is disposed downstream of the fuel cell stack to allow the fuel gas to be exhausted from the fuel cell stack, to be brought into an open condition in a case that the estimating section estimates the occurrence of the water-clogging phenomenon; and a coolant temperature detecting section detecting a temperature of coolant that cools the fuel cell stack, wherein the estimating section is configured to estimate the occurrence of the water-clogging phenomenon responsive to a degree by which the temperature of the coolant is lowered during electric power generation of the fuel cell stack.