Abstract: A fuel cell system and a method for scavenging it are provided. The fuel cell system includes a fuel cell, a fuel gas passage, an oxidant gas passage, a communicating passage, a communicating valve, a monitoring device, a valve controller, a scavenging device and a computing device. The monitoring device monitors a state transition of the fuel cell after a termination of power generation. The valve controller opens the communicating valve when a signal indicative of the state transition meets a predetermined criterion. The scavenging device includes a first scavenging device for the oxidant gas passage, and a second scavenging device for the fuel gas passage. The computing device computes an amount of the oxidant gas required for scavenging according to a system shut off time. The scavenging device conducts scavenging with the amount of the oxidant gas obtained by the computing device.

Abstract: After an ignition switch is turned off, in order to suppress operation of an air compressor and thereby reduce noise, liquid droplets residing in an oxygen-containing gas flow field as well as liquid droplets residing in a fuel gas flow field are removed during separate time periods, such that the flow rate in the oxygen-containing gas flow field and the flow rate in the fuel gas flow field do not become large at the same time. Then, an electrolyte membrane is dried using an oxygen-containing gas, in order to improve the performance upon starting a next operation.

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 comprises a fuel cell stack, a cell voltage monitor, a hydrogen tank, a hydrogen supply channel, an ejector, a hydrogen off-gas channel, a purge valve, a compressor, an air supply channel, a pressure control unit for controlling air pressure, a pilot pressure input channel branching off from the air supply channel and inputting the air pressure to the ejector as pilot pressure, and a control unit for controlling the purge valve and the pressure control unit. The ejector includes a pressure control mechanism which increases the ejector's secondary-side pressure by increasing the area of the nozzle's ejecting hole when the pilot pressure input from the pilot pressure input channel rises. When electricity generation status of the fuel cell stack is judged to be poor, the control unit opens the purge valve after raising the air pressure and the pilot pressure by using the pressure control unit.

Abstract: A fuel cell system allows suppression of the deterioration of a fuel cell even if a part of a membrane configuring the fuel cell is unavailable for power production. The fuel cell is configured with a membrane, and an anode and a cathode provided so as to sandwich the membrane, and produces electric power from reaction of reactive gases via the membrane when the reactive gases are supplied to the anode and the cathode. The fuel cell system is configured with the fuel cell, an MEA power production effective area calculating means for calculating an area of the membrane surface available for power production, an upper limit power producing current calculating means for controlling the total power production of the fuel cell based on the power production effective area calculated by the MEA power production effective area calculating means, and a current controller.

Abstract: This invention provides a fuel cell system preventing from a first valve such as a purge valve exhausting gas outside. The fuel cell system includes a fuel cell stack, an anode off-gas channel, a purge valve and a scavenging gas exhaust valve connected to the anode off-gas channel and exhausting gas inside the anode off-gas channel outside, a drain valve connected to the anode off-gas channel arranged in an upstream side of a connecting point of the purge valve and the scavenging gas exhaust valve and exhausting the moisture exhausted from the anode channel 12 to the anode off-gas channel, and ECU. The control unit is designed to open only the drain valve in a closed condition of the purge valve and the scavenging gas exhaust valve, after the anode off-gas channel is filled with gas in a closed condition of the purge valve, the scavenging gas exhaust valve, and the drain valve during the stop of power generation of the fuel cell stack.

Abstract: A fuel cell system includes a replacing unit for replacing a gas remaining in the anode of the fuel cell with the anode gas supplied anew by the anode gas supply unit when starting up the fuel cell. The amount of the anode gas is set to be lower, if the operation condition determining unit determines that the last operation was performed in a low-temperature and short-time operation mode. The operation condition determining unit sets the amount of the anode gas so that the gas remaining in the anode can be replaced with the anode gas with an entire anode capacity if the anode was been scavenged while no electro-chemical reaction was progressing in the fuel cell. The present invention can set the amount of anode gas appropriately when starting up the fuel cell.

Abstract: When it is detected that the ignition switch is turned off a short period of time after the ignition switch turned on at the temperature below the freezing point, the charge threshold of a capacitor is changed to a larger charge threshold C for increasing the amount of electrical energy charged in the capacitor based on the charge threshold C. The capacitor is used for performing a scavenging process for a sufficient period of time. At the time of starting operation of the fuel cell system at the temperature below the freezing point the next time, using the electrical energy of the capacitor, a fuel cell is warmed rapidly by a heater or the like to start operation of the fuel cell system.

Abstract: A fuel cell system includes a fuel cell stack, a warming up status detector, a warming up completion threshold setter, an informing device, an estimator, and a threshold changer. The warming up status detector is configured to detect a warming up status of the fuel cell stack. The informing device is configured to inform of completion of warming up when a value corresponding to a warming up status detected by the warming up status detector is equal to or higher than a threshold value set by the warming up completion threshold setter. The estimator is configured to estimate whether generated water is frozen in the fuel cell stack. The threshold changer is configured to change the threshold value set by the warming up completion threshold setter in accordance with a freezing state of the generated water in the fuel cell stack estimated by the estimator.

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 calculates amount of fluid discharged from a fuel gas circulation path with water and fuel gas in accordance with an ordinary process map if inside an anode is not scavenged when a fuel cell stops electrochemical reaction; measures amount of water remaining in a fuel gas circulation path in accordance with cumulative electricity output, temperature, or elapsed time after starting the electrochemical reaction if the inside the anode is scavenged previously; and determines whether the inside the fuel gas circulation path is in dry condition or humid condition. The fuel cell system calculates amount of fluid discharged from the fuel gas circulation path with water or the fuel gas in accordance with a map predetermined for the dry condition if the fuel cell system determines that the inside the fuel gas circulation path is in the dry condition.

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: An object of the present invention is to provide a fuel cell system in which a noise and a vibration of a compressor can be suppressed. In order to achieve the above object, the present invention provides a fuel cell system including a fuel cell; a compressor for supplying an oxidant gas to the fuel cell, having a first rotational speed region within which as a rotational speed increases, a noise becomes greater than a predetermined value, and a second rotational speed region within which as the rotational speed increases, the noise becomes equal to or less than the predetermined value; and a compressor controller for controlling the compressor by calculating a command rotational speed for commanding the compressor based on a required amount of power generation.

Abstract: A fuel cell system is provided with a fuel cell that supplies fuel gas to an anode electrode and that supplies oxidant gas to a cathode electrode to generate electric power; a scavenging gas supply device that scavenges the inside of the fuel cell; a temperature detection device that detects a temperature of the inside of the fuel cell; a deterioration countermeasure scavenging device that executes deterioration countermeasure scavenging by the scavenging gas supply device and replaces the accumulated gas accumulated in the anode electrode with the scavenging gas; and a sub-zero countermeasure scavenging device that executes sub-zero countermeasure scavenging with a greater flow volume than the scavenging gas supplied during the deterioration countermeasure scavenging and to discharge the generated water in the inside of the fuel cell.

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: A fuel cell system including: a fuel cell including a fuel gas channel and an oxidant gas channel, which is configured to generate electricity using a fuel gas and an oxidant gas; a diluting unit configured to dilute gas discharged from the fuel gas channel by mixing the discharged gas with a dilution gas which is supplied from an oxidant gas supply unit and passed through and discharged from the fuel cell, and to exhaust the diluted gas to outside; a purge valve configured to purge gas in the fuel gas channel to the diluting unit; a scavenging unit configured to scavenge the fuel gas channel and the oxidant gas channel; and a dilution assist unit configured to supply a dilution assist gas to the diluting unit through an assist passage connected to the diluting unit to assist dilution in the diluting unit, during scavenging by the scavenging unit.

Abstract: A fuel cell system is provided that can suppress the degradation of the MEA and simultaneously assure the merchantability. The fuel cell system 1 includes: a fuel cell 10 that generates electric power by reacting hydrogen gas and oxidant gas; a temperature sensor 103 that detects the temperature of the fuel cell 10; a voltage lower limit calculation portion 31 that sets the voltage threshold to limit the output of the fuel cell 10 based on the temperature detected of the fuel cell 10; a current upper limit calculation portion 32 and the current limiting portion 33 that limits the output of the fuel cell in a case where the voltage generated by the fuel cell 10 is lower than the voltage threshold.

Abstract: The object of the present invention is to provide a fuel cell system enabling an improvement in fuel consumption and a method for controlling thereof. A fuel cell system 1 includes a fuel cell 10, an air pump 21, an air supply channel, a hydrogen supply channel, a hydrogen tank, a hydrogen discharge channel, a hydrogen reflux channel, an air discharge channel, a purge valve 441, and a control device 30. The control device 30 includes a dilution judgment portion 31 judging whether dilution of hydrogen gas has been completed; an air increase portion 33 for increasing an air mass in the air discharge channel; a power production calculation portion 34 calculating an amount of power production based on the air mass increased; and a fuel cell drive portion 35 driving the fuel cell 10 to produce electric power to obtain the amount of power production calculated.

Abstract: A fuel cell system includes a scavenging gas supply device for supplying a scavenging gas to a fuel cell stack; a scavenging switching valve for performing switching between first scavenging for performing scavenging by supplying the scavenging gas to one of a cathode gas passage and an anode gas passage, and second scavenging for performing scavenging by supplying the scavenging gas to the other gas passage; a pressure control device for controlling the pressure of the scavenging gas; and a control part for controlling operations of the scavenging gas supply device, the scavenging switching valve, and the pressure control device. When the scavenging is switched from the first scavenging to the second scavenging via the scavenging switching valve, the pressure of the scavenging gas at the upstream side with respect to the scavenging switching valve becomes lower than the pressure of the scavenging gas during the first scavenging.

Abstract: A fuel cell system including: a fuel cell which generates electrical power through the reaction of a reaction gas; a reaction gas supply device which supplies the reaction gas to the fuel cell; a cooling device which cools the fuel cell by circulating a coolant through the fuel cell; a fuel cell operating temperature output device which outputs a maximum temperature inside the fuel cell as an operating temperature of the fuel cell; and a fuel cell temperature adjustment device which adjusts a temperature inside the fuel cell so that the operating temperature inside the fuel cell is less than a preset upper temperature limit.