Abstract: A fuel-cell system is provided, which includes a fuel cell, a reactive-gas supply unit and a control unit. The reactive-gas supply unit supplies the reactive gases to the fuel cell. The control unit includes an average stoichiometric flow-ratio calculation part and a reactive-gas reduction part. The average stoichiometric flow-ratio calculation part calculates an average stoichiometric flow ratio by averaging stoichiometric flow ratios. A stoichiometric flow ratio is a ratio of an amount of the reactive gases supplied to the fuel cell with respect to a required amount of the reactive gases of the fuel cell in accordance with a required amount of power generation. When the average stoichiometric flow ratio is equal to or greater than a first predetermined value, the reactive-gas reduction part reduces the amount of the reactive gases supplied to the fuel cell so as to lower the stoichiometric flow ratio.

Abstract: A fuel cell system includes: a fuel cell to which a reaction gas is supplied to generate electricity; a circulating system which returns unreacted reaction gas discharged from the fuel cell to an upstream of the fuel cell to thereby circulate the unreacted reaction gas; a discharge device which discharges the unreacted reaction gas from the circulating system; a first pressure detector which detects a pressure at a downstream of the discharge device; and a controller which controls an amount of discharged gas to be discharged from the circulating system by the discharge device, based on the pressure detected by the first pressure detector.

Abstract: A fuel cell system is provided which includes a fuel cell to which fuel gas and oxidizing gas are supplied to generate electricity, a purge valve which purges fuel gas discharged from the fuel cell, a dilutor which mixes the purged fuel gas with the oxidizing gas and purges the purged fuel gas mixed with the oxidizing gas into the atmosphere, and an ECU which stops supply of the oxidizing gas to the fuel cell so as to cause an idle stop and determines whether to permit the idle stop depending on a concentration of the fuel gas in the dilutor.

Abstract: A fuel cell system includes a control device for setting an oxygen-containing gas operating pressure target value on the cathode side using a relative pressure relative to atmospheric pressure, setting a fuel gas operating pressure target value on the anode side using an absolute pressure, and controlling a power generation current of the fuel cell using as command values the relative pressure and the absolute pressure. The control device controls operation of the entire fuel cell system.

Abstract: A fuel cell system includes: a fuel cell that generates an electric power and heat by a reaction of a reaction gas; a heat exchanger; a coolant circuit for a coolant between the fuel cell and the heat exchanger; a coolant circulating pump for circulating the coolant in the coolant circuit; and a drive motor for driving the coolant circulating pump, the coolant receiving and carrying the heat to the heat exchanger by the coolant circuit, the coolant circulating pump, and the drive motor. A rotational speed of the drive motor is controlled according to an upper limit of the rotational speed of the drive motor which may be determined on the basis of a cooling capacity of the heat exchanger, a speed of the vehicle mounting the fuel cell system, a generated electric power, and a flow rate of the reaction gas.

Abstract: A controllable range of an air flow rate and an air pressure in a fuel cell system is calculated from air flow rates and air pressures when the air back pressure valve is fully open and fully closed. A target generation current is calculated from an accelerator position or an auxiliary unit to calculate a target air flow rate and a target air pressure as target values. If the target values are outside the controllable range, it is judged whether the target values exceed an upper limit the controllable range, the target values are decreased onto the upper limit, and if no, the target values are increased onto the lower limit of the controllable range.

Abstract: There is provided a fuel cell for generating a electric power by a reaction of a reaction gas, a reaction gas flow path through which the reaction gas passes, purge section for purging the reaction gas flow path with a purging gas, a purge judging section for judging as to whether or not a purging operation by the purge section is required, and a failure detecting section for detecting a failure of a judgment support device. When the failure of the judgment support device is detected by the failure detecting section, there action gas flow path is purged by the purge section when stopping the power generation of the fuel cell.

Abstract: A reaction gas is supplied to a cathode side of a fuel cell at a flow rate higher than that for a usual operation of the fuel cell to thaw the fuel cell system at startup in a freezing state of the system when the system has experienced a temperature lower than an operation temperature of an anode off-gas. A thawing state of the system is detected on the basis of at least two of temperatures of the anode off-gas, a cathode off gas, and a radiator liquid of the fuel cell to control supplying the reaction gas to the cathode side at a usual operation flow rate. An actual increase rate of the temperature of the anode off-gas is obtained and an increase rate of the temperature of the anode off-gas is calculated from the self-heating value to be compared to determine the thawing state.

Abstract: A fuel cell system wherein even if the fuel cell is exposed to a cold environment, stabilization of power generation is possible. The fuel cell system comprises: a fuel cell in which electric power is generated by a reaction of reaction gases; purging means for purging at least one of reaction gas flow paths through which reaction gases flow; thermal detecting means for detecting a temperature of the fuel cell; low-temperature determining means, which determines that the temperature of the fuel cell is low every time it is below a predetermined temperature; and purging control means for purging the fuel cell when the low-temperature determining means determines, after an input of a power generation stop signal, that the temperature of the fuel cell is low.

Abstract: A fuel cell system includes a fuel cell having a fuel gas flow path and an oxidant gas flow path; a compressor for supplying humidified air to the oxidant gas flow path; a back-pressure regulating valve for controlling pressure of humidified air in the oxidant gas flow path; a pressure sensor for measuring the pressure of the humidified air in the oxidant gas flow path; and a control section for controlling the compressor and the back-pressure regulating valve. In this system, the pressure of humidified air in the oxidant gas flow path is regulated to become equal or approximate to a target pressure by the back-pressure regulating valve. When the pressure difference between the pressure measured by the pressure sensor and the target pressure is larger than a predetermined pressure difference, the control section corrects operating conditions of the compressor, so that the measured pressure becomes the target pressure.

Abstract: A fuel cell system enables time required for purging to be reduced without a major increase in discharge gas concentration at a time of purging. It comprises a fuel cell; a fuel gas supply path for supplying the fuel gas to an anode; an oxidizing gas supply path for supplying an oxidizing gas to a cathode; a fuel gas circulating path for returning an unreacted fuel gas to an anode inlet side; a dilution box for diluting the fuel gas by the oxidizing gas and for discharging it to outside; and a fuel gas discharge path connecting the fuel gas circulating path and a dilution box discharge gas inlet. A drain valve, a purge valve and an air discharge valve are provided, opening areas of which are different from one another. The drain valve with a smallest opening area is initially opened.

Abstract: A fuel cell system and an idle stop controlling method for the fuel cell system. The fuel cell system includes: a fuel gas supply means for supplying fuel gas; an oxidant gas supply means for supplying oxidant gas; a fuel cell to which the fuel gas and the oxidant gas are supplied for generation of electricity; an idle stop means for stopping generation of electricity by the fuel cell to perform idle stop; and an unstable state detection means for detecting whether the generation of electricity by the fuel cell is unstable. If the unstable state detection means detects that generation of electricity by the fuel cell is unstable, idle stop by the idle stop means is prohibited so that the fuel cell continues to generate electricity.

Abstract: The following control is performed. During startup of a fuel cell 1, a fuel gas is supplied to an anode 1b of the fuel cell 1 and an oxidant gas is supplied to a cathode 1c of the fuel cell 1, thereby starting power generation. Fuel gas externally emitted from the abode 1b is diluted with an oxidant gas externally emitted from the cathode 1c. From a start to end of discharge of a fuel gas from the anode 1b, a flow rate required for dilution of the oxidant gas, and a flow rate required for an external output, being calculated on the basis of the power requested for the fuel cell 1, are respectively calculated. The flow rate required for dilution and the flow rate required for an external output are compared, and a larger flow rate is set as a flow rate of the oxidant gas.

Abstract: The fuel cell system is equipped with a fuel cell for generating power by a reaction of fuel and oxidizer gases; a fuel gas flow passage for passing the fuel gas; an oxidizer gas flow passage for passing the oxidizer gas; a sweeping gas supply mechanism for sweeping any of the fuel and oxidizer gas flow passages by a sweeping gas; a sweeping determination mechanism for determining whether to perform sweeping by the sweeping gas supply mechanism, when receiving a stop request for stopping the fuel cell system; a pressure reduction mechanism for reducing a pressure within one of the flow passages lower than when determined not to perform the sweeping, when determined to perform the sweeping by the sweeping determination mechanism; and an actuation mechanism for actuating the sweeping gas supply mechanism after the pressure within the flow passage is reduced by the pressure reduction mechanism.

Abstract: A fuel cell system is equipped with a fuel cell for generating power by an electrochemical reaction of a fuel gas and an oxidizer gas, a fuel gas supply mechanism for supplying the fuel gas to the fuel cell, a supply amount adjustment mechanism for adjusting a supply amount of the fuel gas, a fuel gas flow passage for passing the fuel gas, a purge valve for purging a gas within the fuel gas flow passage outside, and a control mechanism for opening the purge valve when a stop request of the fuel cell is output, wherein when an activation request of the fuel cell is output, the control mechanism controls the supply amount adjustment mechanism so that a pressure within the fuel gas flow passage becomes smaller than a minimum pressure in a normal power generation and larger than an atmospheric pressure.

Abstract: A fuel cell system of the present invention is mounted on a moving object and is equipped with a fuel cell for generating power by chemically reacting a fuel gas supplied to an anode and an oxidizer gas supplied to a cathode; a cooling mechanism for cooling the fuel cell by radiating heat of a refrigerant circulating in the fuel cell into an atmosphere; a speed detection mechanism for detecting a moving speed of the moving object; an outside air temperature detection mechanism for detecting an outside air temperature; a cooling amount estimation mechanism for estimating a cooling amount of the fuel cell by the cooling mechanism, based on the moving speed and the outside air temperature; and an upper limit value set mechanism for setting an upper limit value of a power generation current, based on an estimation result of the cooling amount estimation mechanism.

Abstract: A fuel cell system has a fuel cell, a fuel supply device, a gas discharge valve, a voltage detecting device and a control device. The fuel supply device supplies a fuel gas to the fuel cell. The gas discharge valve discharges the fuel gas into an external environment. The voltage detecting device detects an output voltage of the fuel cell. The control device controls a discharging process when a request for starting the fuel cell is given. The discharging process includes introducing the fuel gas from the fuel supply device into a predetermined passage, opening the gas discharge valve and discharging residuals staying in the passage into the external environment. When the control device receives the request and determines that the output voltage has reached a first threshold before the discharging process has not been completed, the control device starts power generation irrespective of completion of the discharging process.

Abstract: A current limiting system for fuel cells, which limits electric current generated by a fuel cell stack including a plurality of single cells generating electricity by a chemical reaction between fuel gas and oxidant.

Abstract: A fuel cell system includes: a fuel cell which generates electrical power from a chemical reaction of a reaction gas; a discharge path for discharging the reaction gas supplied to the fuel cell; a discharge valve which is provided in the discharge path and discharges the reaction gas from the discharge path; and valve control units for controlling opening of the discharge valve, wherein the valve control units are adapted such that, since the discharge valve has been opened by a valve open command issued by one of the valve control units, the valve control units prohibit the discharge valve from being opened by a valve open command issued by any of the other valve control units until a predetermined time period elapses.

Abstract: A reaction gas supply apparatus for a fuel cell is able to adapt to various kinds of operating states, and can provide improved responsiveness with respect to a required output. The apparatus has: a compressor 2 that supplies pressurized air to a cathode electrode of a fuel cell 1; a hydrogen supply device 30 that supplies hydrogen to an anode electrode of the fuel cell 1; a control device 10 that regulates the pressure of the cathode electrode by controlling the compressor 2 according to an operating state of the fuel cell 1; and a regulator 5 that is applied with the air pressure of the cathode electrode as a reference pressure, and regulates the supply pressure to the anode electrode based on this air pressure. Moreover there is provided a pressure regulator 39 that is capable of regulating the reference pressure that is applied to the regulator 5, by discharging air from an air flow passage for the air pressure that is applied to the regulator 5.