Toyota Jidosha Kabushiki Kaisha

Hiromi Tanaka

Osamu Yumita

Yoshiaki Naganuma

Nobukazu Mizuno

Masashi Fuji

Takayoshi Tezuka

Masaaki Matsusue

Tomotaka Ishikawa

Yasushi Araki

Kyo Hattori

Masaaki Yamaoka

Keigo Suematsu

Tatsuo Sugitani

Shigeto Kajiwara

Takahide Izutani

Yuichi Sakajo

Yoshimasa Negishi

Kazumasa Takada

Kouji Yotsuya

Kohsei Yoshida

A fuel cell system includes a fuel cell, an injection device configured to inject anode gas, an ejector mechanism through which the anode gas injected from the injection device flows, a circulation path configured to return the anode gas, discharged from the fuel cell, to the ejector mechanism, a supply path configured to supply the anode gas, discharged from the fuel cell together with the anode gas injected from the injection device from the ejector mechanism, to the fuel cell, and a controller.

Fuel cell system

A fuel cell includes: a membrane electrode assembly; cathode and anode-side water-repellent layers; a cathode-side separator that includes a cathode gas passage and an air exhaust manifold communicated to the cathode gas passage. The cathode gas passage includes a water exhaust inhibiting portion and a water storage portion. The water exhaust inhibiting portion is provided on a lowermost passage positioned on a lowermost side in a gravity direction. The water storage portion is provided upstream of the water exhaust inhibiting portion such that liquid water is stored in the water storage portion by the water exhaust inhibiting portion. A liquid water connection portion is provided in the water-repellent layer so as to pass through the water-repellent layer such that liquid water flows between the catalyst layer and the water storage portion.

Fuel cell and fuel cell system

An exhaust state control device for a fuel cell for a mobile unit includes an exhaust gas temperature sensor () that measures the temperature of exhaust gas in a discharge passage that discharges the exhaust gas from the main body of the fuel cell, and an ambient temperature sensor (A) that measures the temperature of ambient air to which exhaust gas is to be discharged. If, based on the difference between the exhaust gas temperature and the ambient temperature, it is determined that white smoke is generated, it is determined whether a condition to reduce white smoke is satisfied. When a first condition is satisfied, a process to reduce white smoke is activated. When a second condition, which requires further reduction of white smoke than under the first condition, is satisfied, a process to suppress the generation of white smoke is activated.

Exhaust state control device for fuel cell for mobile unit

A fuel cell system suppresses the deterioration of an electrolyte membrane of a fuel cell. The fuel cell system comprises: a temperature rise speed calculation unit for calculating a target temperature rise speed of the fuel cell using a temperature of the fuel cell and a water content of the fuel cell; and a drive control unit for controlling a drive of the cooling water pump using the temperature rise speed of the fuel cell and the target temperature rise speed calculated by the temperature rise speed calculation unit. The drive control unit controls the drive of the cooling water pump such that a circulation amount of the cooling water is decreased when the temperature rise speed of the fuel cell is below the target temperature rise speed and controls the drive of the cooling water pump such that the circulation amount of the cooling water is increased when the temperature rise speed of the fuel cell is equal to or greater than the target temperature rise speed.

A fuel cell system includes a fuel cell stack and a fuel gas piping system which supplies a fuel gas to the fuel cell stack, and is capable of, at starting below a freezing point, selectively performing a rapid warm-up operation to generate electric power at an air stoichiometric ratio lower than that at starting at ordinary temperature, while revolving a circulating pump, and the fuel cell system further includes a clogging determination unit which determines whether or not clogging arises from freezing in a fuel gas passage of the fuel cell stack, or the fuel gas piping system, wherein when the clogging arises, the circulating pump is stopped in the rapid warm-up operation, and termination conditions of the rapid warm-up operation are changed in accordance with a clogging volume.

Fuel cell system and control method at starting in the fuel cell system

A fuel cell system includes a fuel cell, an operation controller and an air-conditioning mechanism. In response to a heating request for the air-conditioning mechanism during ordinary operation where the fuel cell is operated at an operating point on a current-voltage characteristic curve of the fuel cell, the operation controller compares a heat value-based required current value with an output-based required current value. When the output-based required current value is equal to or greater than the heat value-based required current value, the operation controller causes the fuel cell to be operated at an operating point on the current-voltage characteristic curve. When the output-based required current value is smaller than the heat value-based required current value, the operation controller controls the operating point of the fuel cell to an operating point of lower power generation efficiency than that of the operating point on the current-voltage characteristic curve.

When starting operation of a fuel cell below the freezing point, a fuel cell system adjusts the open degree of a hydrogen pressure adjusting valve, introduces hydrogen to a hydrogen entrance of the fuel cell so as to make the total pressure of the hydrogen entrance a first pressure, and starts a hydrogen circulation pump. If at least one of the cell voltages acquired by a cell voltmeter is below a predetermined voltage, the system determines that clogging is caused in a hydrogen flow channel in the fuel cell. When it is determined that clogging is present, the open degree of the pressure adjusting valve is adjusted and hydrogen is introduced to the hydrogen entrance so that the total pressure of the hydrogen entrance is a second pressure which is higher than the first pressure. Then, the hydrogen circulation pump is stopped and the fuel cell is warmed up to dissolve the clogging of the hydrogen flow channel. Thus, it is possible to suppress degradation of the fuel cell upon an operation start below the freezing point.

An object is to suppress the degradation of durability due to a heat concentration while performing a rapid warm-up operation as necessary, when starting a fuel cell system at temperatures below freezing point. In order to achieve such an object, the present invention stores in a memory an operation termination condition of the last operation of the system, data such as the start-up temperature, or the remaining amount of product water at the time of the last scavenging; calculates the remaining amount of product water based on data read out from the memory at the time of starting the system to make judgments, from the remaining amount and the start-up temperature, on whether or not a rapid warm-up of the system is necessary and whether to start without circulating the cooling water when a rapid warm-up is necessary; and conducts, based on the judgment result provided by the judgment means, with or without circulating the cooling water, a low-efficiency power generation where a reactant gas to be supplied to the fuel cell is less than that in a normal power generation and an electronic power loss is larger than that in a normal power generation. The data includes, for example, an impedance, a temperature of the fuel cell and a scavenging air amount at the last termination of the operation of the fuel cell.

Fuel cell system and start-up control method therefor

A fuel cell system includes a fuel cell, a secondary battery, an oxidizing gas supplier, a gas supply flow regulator, an oxidizing gas supply path, a cathode off-gas exhaust path, a bypass flow path, a flow regulator, an available power output acquirer, and an operation controller, wherein the gas supply flow regulator regulates the gas supply flow rate to cause the oxidizing gas supplier to supply an excess gas flow rate, which is set to be greater than a target fuel gas-requiring gas flow rate, wherein the target fuel gas-requiring gas flow rate is the fuel cell-requiring gas flow rate to be supplied to the fuel cell in order to achieve the target current value, when the available power output is less than a minimum amount of electric power required for the oxidizing gas supplier to increase the gas supply flow rate from 0 to a preset gas flow rate within a preset time period, and the operation controller controls the flow regulator to make the bypass flow rate equal to a difference gas flow rate between the excess gas flow rate and the target fuel cell-requiring gas flow rate.

Provided is a fuel cell system that performs a warm-up operation by reducing a supply of oxidant gas to a fuel cell, the system having: a fuel cell; and a control unit that regulates amounts of oxidant gas and fuel gas supplied to the fuel cell and controls a power-generation state of the fuel cell. During the warm-up operation with a reduced supply of oxidant gas to the fuel cell, the control unit varies a voltage of the fuel cell for a short period of time to obtain current-voltage characteristics which indicate a relationship of an output voltage and an output current of the fuel cell, calculates an effective catalyst area of the fuel cell based on the obtained current-voltage characteristics, and determines whether the warm-up operation of the fuel cell can be stopped or not based on the calculated effective catalyst area.

The invention constructs a system which vaporizes a liquid raw material in a vaporizing section and steam-reforms the vaporized raw material in a reforming section to generate hydrogen. A pressure regulating valve for regulating the pressure in the vaporizing section is disposed at anywhere from the vaporizing section to downstream of the reforming section. When a hydrogen requirement is increased, the pressure regulating valve is controlled to decrease the pressure in the vaporizing section. The pressure reduction makes it possible to promote vaporization in the vaporizing section such that the rate of generation of steam can be improved. Moreover, during start-up of the system, the control mode is changed to open the pressure regulating valve, thereby limiting the rate of increase in pressure just after the generation of reformed gas has started.

Hydrogen generating system

A braking force control device and method performs brake assist control. A timer CT begins to count the elapsed time, for example, from when the elevation gradient &Dgr;P,of a master cylinder pressure P,becomes equal to or greater than a first threshold value TH,. It is determined that an emergency brake operation is executed, when the master cylinder pressure P,becomes equal to or greater than a second threshold value TH,before a predetermined time has passed, and then the brake assist control starts.

Growing community of inventors

Toyota, Japan

Hiromi Tanaka