Abstract: A method for controlling a fuel cell system including a fuel cell which includes an anode electrode and a cathode electrode sandwiching a solid polymer electrolyte membrane therebetween, includes driving a pump to supply an oxidant gas to the cathode electrode. The pump has a minimum supply amount of the oxidant gas. A fuel gas is supplied to the anode electrode to generate electric power via an electrochemical reaction between the fuel gas and the oxidant gas. It is determined whether a target amount of the oxidant gas to be supplied to the cathode electrode is lower than the minimum supply amount. An opening degree of a pressure adjusting valve is adjusted to adjust an amount of the oxidant gas supplied to the cathode electrode to be the target amount when the target amount is determined to be lower than the minimum supply amount.

Abstract: A method for stopping a fuel cell system includes supplying a fuel gas containing a fuel to an anode of a fuel cell which is to generate electric power. An oxidant gas containing an oxidant is supplied to a cathode of the fuel cell. A concentration of the oxidant gas in the cathode is reduced. An output voltage of the fuel cell is lowered while a slope of a change in the output voltage with respect to elapsed time is controlled such that an output current of the fuel cell has a predetermined relationship with a predetermined current reference value.

Abstract: A method of shutting down a fuel cell system includes a first step of supplying hydrogen gas and air to a fuel cell stack to thereby cause the fuel cell stack to generate electricity, and a second step of stopping supply of the hydrogen gas, and then supplying air to the fuel cell stack so as to cause the fuel cell stack to generate electricity upon detection of a command to shut down the fuel cell stack. In the second step, when the pressure of the hydrogen gas is lowered to a preset lower-limit value based on an anode pressure, which actually is measured, the fuel cell stack is caused to stop generating electricity.

Abstract: A fuel cell system comprises: a turbo type oxidizing agent pump, the rotary shaft of which is pivotally supported by an air bearing to take in and supply an oxidizing agent gas to a fuel cell by the rotary motion; an actual flow rate detection means for the oxidizing agent gas; a pressure adjustment means for the oxidizing agent gas; a rotary speed monitoring means for the oxidizing agent pump; and a control means which, when the rotary speed of the oxidizing agent pump is within the range of the minimum rotary speed that allows the rotary shaft to be pivotally supported by the air bearing, if the actual flow rate of the oxidizing agent gas is larger than a target flow rate, increases the pressure of the oxidizing agent gas via the pressure adjustment means.

Abstract: A controller (control portion) of a fuel cell system is provided with a flow path switching control device that switches a thermostat valve (flow path switching valve) so that, after a fuel cell has stopped generating electric power, coolant is supplied to a radiator circulation path until the coolant temperature becomes a second temperature threshold value that is lower than a first temperature threshold value.

Abstract: A method of shutting down a fuel cell system includes a first step of supplying hydrogen gas and air to a fuel cell stack to thereby cause the fuel cell stack to generate electricity, and a second step of stopping supply of the hydrogen gas, and then supplying air to the fuel cell stack so as to cause the fuel cell stack to generate electricity upon detection of a command to shut down the fuel cell stack. In the second step, when the pressure of the hydrogen gas is lowered to a preset lower-limit value based on an anode pressure, which actually is measured, the fuel cell stack is caused to stop generating electricity.