Abstract: A fuel cell system includes a fuel cell stack, a circulation circuit, a gas liquid separator section, a purge channel, a purge valve and an ECU. In a method of operating the fuel cell system at low temperature, after start-up of the fuel cell system, the ECU performs a freezing determination processing step of determining freezing or non-freezing of the gas liquid separator, and in the case where freezing of the gas liquid separator is determined in the freezing determination step, the ECU performs a freezing confirmation processing step of immediately opening the purge valve for predetermined time.

Abstract: A fuel cell system includes a fuel cell stack, a plurality of injectors capable of adjusting a flow rate of anode gas supplied to the fuel cell stack, and an ECU causing the plurality of injectors to operate. The plurality of injectors include a main injector, and a BP injector that operates when power that exceeds a prescribed power generation amount is generated. The ECU performs an operational check of causing the BP injector to operate at least once and judging whether the BP injector is normal or abnormal, during a period from when the fuel cell system is activated to when the fuel cell system stops.

Abstract: A fuel cell vehicle is mounted with a fuel cell system including a fuel cell stack and a battery. The fuel cell vehicle controls operation of the fuel cell system with an ECU, to perform standby power generation from activation to when travel is allowed and to perform power generation during operation of the fuel cell vehicle after travel has been allowed. In an activation method, the power generation current is increased in accordance with a low-temperature efficiency rate during the power generation during operation, the battery is charged and the power generation current is increased in accordance with a standby current increase rate that is lower than the low-temperature efficiency rate during the standby power generation.

Abstract: A fuel cell system includes a fuel cell stack, a circulation circuit, a gas liquid separator section, a purge channel, a purge valve and an ECU. In a method of operating the fuel cell system at low temperature, after start-up of the fuel cell system, the ECU performs a freezing determination processing step of determining freezing or non-freezing of the gas liquid separator, and in the case where freezing of the gas liquid separator is determined in the freezing determination step, the ECU performs a freezing confirmation processing step of immediately opening the purge valve for predetermined time.

Abstract: A fuel cell system includes a fuel cell stack, a plurality of injectors capable of adjusting a flow rate of anode gas supplied to the fuel cell stack, and an ECU causing the plurality of injectors to operate. The plurality of injectors include a main injector, and a BP injector that operates when power that exceeds a prescribed power generation amount is generated. The ECU performs an operational check of causing the BP injector to operate at least once and judging whether the BP injector is normal or abnormal, during a period from when the fuel cell system is activated to when the fuel cell system stops.

Abstract: A fuel cell vehicle is mounted with a fuel cell system including a fuel cell stack and a battery. The fuel cell vehicle controls operation of the fuel cell system with an ECU, to perform standby power generation from activation to when travel is allowed and to perform power generation during operation of the fuel cell vehicle after travel has been allowed. In an activation method, the power generation current is increased in accordance with a low-temperature efficiency rate during the power generation during operation, the battery is charged and the power generation current is increased in accordance with a standby current increase rate that is lower than the low-temperature efficiency rate during the standby power generation.

Abstract: A low-temperature startup method for a fuel cell, includes detecting a temperature of the fuel cell. It is determined whether the temperature is lower than a threshold temperature. A drying operation to dry the fuel cell is increased when the temperature is determined to be lower than the threshold temperature upon starting the fuel cell to generate electric power via an electrochemical reaction between fuel gas and oxidant gas.

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: Oxidant gas flows to the fuel cell stack through an oxidant gas supply channel. Oxidant off-gas is discharged from the fuel cell stack through an oxidant off-gas exhaust channel. A refrigerant is discharged from the fuel cell stack through a refrigerant exhaust channel. An outlet sealing valve is provided in the oxidant off-gas exhaust channel. The outlet sealing valve includes a main body, a valve seat, a valve body, and a refrigerant passage. The main body has a passage through which the oxidant off-gas flows. The valve seat is provided in the passage. The valve body is provided in the passage to be seated on the valve seat to close the passage. The refrigerant passage is branched off from the refrigerant exhaust channel. The refrigerant flows in a vicinity of at least one of the valve seat and the valve body through the refrigerant passage.

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 power generation stopping method for a fuel cell system including a fuel cell, includes continuing generating electric power by the fuel cell via electrochemical reaction between fuel gas and oxidant gas during a post running period after the fuel cell system is ordered to stop. A coolant is supplied at a first flow rate to the fuel cell during the post running period until temperature of the fuel cell reaches a threshold temperature. A coolant is supplied to the fuel cell at a second flow rate larger than the first flow rate during the post running period after the temperature of the fuel cell has reached the threshold temperature.

Abstract: A low-temperature startup method for a fuel cell, includes detecting a temperature of the fuel cell. It is determined whether the temperature is lower than a threshold temperature. A drying operation to dry the fuel cell is increased when the temperature is determined to be lower than the threshold temperature upon starting the fuel cell to generate electric power via an electrochemical reaction between fuel gas and oxidant gas.

Abstract: A fuel cell system includes a fuel cell stack having a membrane electrode assembly and an internal reactant gas passage, a unit that detects or estimates an actual retained water quantity (R.W.Q.), and a power generation control unit having a normal-time mode, a normal-time drying mode and a stop-time drying mode. In the normal-time drying mode, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time mode until the actual R.W.Q. is decreased to a target R.W.Q. In the stop-time drying mode, when the actual R.W.Q. is equal to or more than a flooding threshold at a time of detection of a system stop instruction, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time drying mode until the actual R.W.Q. is decreased to a target R.W.Q.

Abstract: Oxidant gas flows to the fuel cell stack through an oxidant gas supply channel. Oxidant off-gas is discharged from the fuel cell stack through an oxidant off-gas exhaust channel. A refrigerant is discharged from the fuel cell stack through a refrigerant exhaust channel. An outlet sealing valve is provided in the oxidant off-gas exhaust channel. The outlet sealing valve includes a main body, a valve seat, a valve body, and a refrigerant passage. The main body has a passage through which the oxidant off-gas flows. The valve seat is provided in the passage. The valve body is provided in the passage to be seated on the valve seat to close the passage. The refrigerant passage is branched off from the refrigerant exhaust channel. The refrigerant flows in a vicinity of at least one of the valve seat and the valve body through the refrigerant passage.

Abstract: A fuel cell system includes a fuel cell stack having a membrane electrode assembly and an internal reactant gas passage, a unit that detects or estimates an actual retained water quantity (R.W.Q.), and a power generation control unit having a normal-time mode, a normal-time drying mode and a stop-time drying mode. In the normal-time drying mode, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time mode until the actual R.W.Q. is decreased to a target R.W.Q. In the stop-time drying mode, when the actual R.W.Q. is equal to or more than a flooding threshold at a time of detection of a system stop instruction, the fuel cell stack is caused to generate electric power while being dried more than in the normal-time drying mode until the actual R.W.Q. is decreased to a target R.W.Q.

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.