Abstract: A fuel cell system supplies anode and cathode gases, and generates power through an electrochemical reaction of the gases in accordance with a load. The system includes a compressor that supplies the cathode gas to a fuel cell stack, and a pressure regulator valve that adjusts the pressure of the cathode gas in the fuel cell stack. The system sets a target cathode pressure based on a power generation request to the fuel cell stack, and controls an operation amount of the compressor and an opening degree of a pressure regulator valve based on the target cathode pressure. The temperature of air discharged by the compressor is restricted to an upper temperature limit by restricting the operation amount of the compressor and/or the opening degree of the pressure regulator valve based on two parameters, i.e., the inlet temperature and the torque of the compressor.

Abstract: A fuel cell system includes: a cathode pressure control unit configured to control a pressure of a cathode gas to be supplied to the fuel cell stack on the basis of a load of the fuel cell stack; and an anode pressure control unit configured to control a pressure of an anode gas to be supplied to the fuel cell stack to become higher than the pressure of the cathode gas so that a differential pressure between the pressure of the anode gas and the pressure of the cathode gas becomes a predetermined differential pressure or lower. The anode pressure control unit controls, at a time of recovery from idle stop, the pressure of the anode gas to be supplied to the fuel cell stack to a recovery-time pressure, the recovery-time pressure being obtained by adding the predetermined differential pressure to a predetermined pressure corresponding to an atmosphere pressure.

Abstract: A fuel cell system includes a fuel cell, a control valve and a controller. The fuel cell is configured to receive anode gas and cathode gas to generate electric power. The control valve is configured to control pressure of the anode gas being fed to the fuel cell through an anode flow channel. The controller controls the control valve to periodically increase and decrease the pressure of the anode gas flowing through the anode flow channel in an area downstream of the control valve. The controller sets an anode pressure differential value for the anode gas resulting from periodic increasing and decreasing of the pressure of the anode gas based on a requested fuel cell output. The controller determines a quantity of liquid in the anode flow channel. The controller decreases the anode pressure differential value that was set based on the requested fuel cell output.

Abstract: A fuel cell system including a cathode gas supply system of a cathode gas bypass type includes a first flow rate sensor which detects a cathode gas flow rate to be supplied by the compressor, a second flow rate sensor which detects a cathode gas flow rate to be supplied to the fuel cell, a bypass valve which controls a cathode gas flow rate flowed in the bypass channel, a bypass valve controlling unit configured to execute an open/shut-off control of the bypass valve in accordance with an operation state of the fuel cell system, and a mismatch diagnosing unit configured to detect a mismatch of detected values of the first flow rate sensor and the second flow rate sensor based on the detected values of the both sensors during total shut-off of the bypass valve.

Abstract: A fuel cell system supplies anode gas and cathode gas to a fuel cell and generates electric power in accordance with a load. The fuel cell system configured to include a cathode gas control unit controls a pressure of the cathode gas on the basis of the load, an anode gas control unit configured to cause a pressure of the anode gas to pulsate on the basis of the pressure of the cathode gas and a pulsation amplitude. The pulsation amplitude is determined on the basis of an operating condition of the fuel cell. The fuel cell system includes an anode gas partial pressure maintenance control unit configured to increase the pressure of the anode gas in accordance with a condition of an impurity within the fuel cell. The cathode gas control unit configured to make the pressure of the cathode gas higher when a pressure difference between the pressure of the anode gas and the pressure of the cathode gas is large than when the pressure difference is small.

Abstract: A fuel cell system comprises a compressor configured to supply the cathode gas to the fuel cell, an intercooler provided downstream of the compressor and configured to cool the cathode gas discharged from the compressor, a pressure regulating valve configured to adjust a pressure downstream of the intercooler, and a controller. The controller computes a first target pressure of the intercooler downstream pressure according to a target output of the fuel cell and computes a second target pressure of the intercooler downstream pressure according to the intercooler downstream temperature. Then, the controller sets smaller one of the first and second target pressures as a target pressure of the intercooler downstream pressure and controls the compressor and the pressure regulating valve according to the target pressure.

Abstract: A fuel cell system includes: a compressor configured to adjust a flow rate of a cathode gas to be supplied to a fuel cell; a pressure regulating valve configured to adjust a pressure of the cathode gas to be supplied to the fuel cell; a target pressure calculating unit configured to calculate a target pressure of the cathode gas to be supplied to the fuel cell while taking into consideration a load of the fuel cell and a heat protecting requirement of the fuel cell system; a target pressure calculating unit configured to calculate a target pressure of the cathode gas to be supplied to the fuel cell while taking into consideration a load of the fuel cell and a heat protecting requirement of the fuel cell system; a target flow rate calculating unit configured to calculate a target flow rate of the cathode gas to be supplied to the fuel cell in accordance with the load of the fuel cell and the target pressure of the cathode gas; and a control unit configured to control the compressor and the pressure regulating

Abstract: A fuel cell stack obtained by stacking a plurality of fuel cells has an internal manifold that extends in a stacking direction of the fuel cells to externally discharge a gas used in the fuel cell, and an extension member that adjoins an inner wall surface of the internal manifold and extends in the stacking direction. The extension member is a bar-shaped member provided in an opposite side to a side where a gas from the fuel cells flows to the inside of the internal manifold and has a sloping surface making an acute angle with an inner-wall lower surface of the internal manifold.

Abstract: A fuel cell system calculates a target value of a flow rate of cathode gas to be supplied to a fuel cell stack according to a request of the fuel cell stack, controls a flow rate of the cathode gas to be supplied by the compressor according to an operating state of the fuel cell system, controls a bypass valve based on a target fuel cell supply flow rate so that the flow rate of the cathode gas to be supplied from the compressor to the fuel cell stack reaches the target fuel cell supply flow rate, and limits the flow rate of the cathode gas to be supplied by the compressor when the bypass valve has a predetermined opening and the flow rate of the cathode gas to be supplied to the fuel cell stack is not smaller than the target fuel cell supply flow rate.

Abstract: A fuel cell system includes a compressor provided in a cathode gas supply passage configured to feed the cathode gas under pressure to the fuel cell, a bypass passage configured to discharge the cathode gas fed under pressure by the compressor to a cathode gas discharge passage while bypassing the fuel cell, a bypass valve provided in the bypass passage and configured to adjust a flow rate of the cathode gas flowing in the bypass passage, a system stopping unit configured to stop the fuel cell system by performing a predetermined stop sequence process when a request to stop the fuel cell system is made, and a stop-time bypass valve control unit configured to control a valve body of the bypass valve to a predetermined initialization position in parallel with the sequence process during the stop sequence process.

Abstract: A fuel cell system includes a target pressure setting unit configured to periodically and repeatedly set a target upper limit pressure and a target lower limit pressure as a target pressure of anode gas. An upper limit pressure setting unit is configured to set the smaller one of an upper limit value based on durability performance and an upper limit value based on output performance as an upper limit pressure of the anode gas. The target pressure setting unit sets a value smaller than the upper limit value as the target upper limit pressure when the upper limit value based on the durability performance of the fuel cell is selected as the upper limit pressure of the anode gas, and sets a pressure higher than the upper limit value as the target upper limit pressure when the upper limit value based on the output performance is selected.

Abstract: A fuel cell stack includes a heat exchange unit that performs heat exchange between a gas mixture containing source hydrogen and a circulating gas and cooling water used for controlling the temperature of the fuel cell stack. A system controller adjusts the temperature of the cooling water by controlling a temperature control unit on the basis of the temperature of source hydrogen flowing into a junction at which the source hydrogen and a circulating gas are mixed such that the temperature of a source/recirculated hydrogen mixture that is mixed at the junction and that is supplied to the fuel cell stack is kept within a managed temperature range.

Abstract: A fuel cell system supplies a fuel cell with an anode gas and a cathode gas, thereby generating electric power. The fuel cell system includes: a control valve for controlling a pressure of the anode gas in the fuel cell; a buffer part for accumulating an anode off-gas discharged from the fuel cell; an off-gas discharge passage for connecting the fuel cell and the buffer part with each other; a purge passage connected to the off-gas discharge passage; a purge valve; a purge unit configured to open the purge valve to discharge the gas in the buffer part to an outside of the fuel cell system; and a pressure control unit configured to decrease the pressure of the anode gas in the fuel cell from a first predetermined pressure to a second predetermined pressure, thereby controlling the gas in the buffer part to flow backward to the fuel cell side.

Abstract: For implementing a stop control which extracts a current from a fuel cell and consumes a cathode side oxygen at a system stop, the current extraction from the fuel cell is ended in a state that a certain quantity of oxygen smaller than when the current extraction is started remains on a cathode side of the fuel cell. With this, the hydrogen movement to the cathode side after the system stop can be effectively suppressed and thereby a cathode internal hydrogen concentration at the system start can be kept low, thus making it possible to properly process the cathode side hydrogen at the system start.

Abstract: A fuel cell system includes a pressure regulating valve for controlling a pressure of an anode gas, a purge valve for controlling a discharge amount of an anode off-gas, the purge valve being configured to change an opening area thereof at least on two stages, a pulsation operation control means configured to control the pressure regulating valve so that the pressure of the anode gas in a fuel cell when a load is high becomes higher than when the load is low, and so that the pressure of the anode gas is periodically increased and decreased at a predetermined load, and a purge valve control means configured to increase the opening area of the purge valve used during a descending transition operation so that the opening area becomes larger than the opening area used during other operations.

Abstract: A fuel cell system configured to generate power by supplying anode gas and cathode gas to a fuel cell includes a control valve for controlling a pressure of the anode gas to be supplied to the fuel cell, a buffer unit configured to store anode off-gas to be discharged from the fuel cell, a purge valve configured to adjust a flow rate of the anode off-gas discharged from the buffer unit, a pulsating operation unit configured to increase and vary the pressure of the anode gas downstream of the control valve according to a load of the fuel cell, and a purge unit configured to control an opening of the purge valve according to the load of the fuel cell. The purge unit increases the opening of the purge valve controlled according to the load of the fuel cell during a down transient operation in which the load of the fuel cell decreases.

Abstract: A fuel cell system that generates power by supplying anode gas and cathode gas to a fuel cell has a control valve that controls pressure of the anode gas supplied to the fuel cell, a pulsation operation unit that causes pulsation of pressure of anode gas in the fuel cell in accordance with a predetermined pressure by controlling an opening degree of the control valve based on an operating condition of the fuel cell system, and a stagnation point determination unit that determines, based on a change in the pressure of the anode gas in the fuel cell, whether or not a stagnation point exists where an anode gas concentration is locally low in the fuel cell. When the stagnation determining unit determines that the stagnation point exists in the fuel cell, the pulsation operation unit increases the predetermined pressure in execution of a pulsation operation.

Abstract: In a fuel cell system including a load and a fuel cell stack connected to the load and supplying an anode gas and a cathode gas to the fuel cell stack to generate power according to the load, the fuel cell system includes, a pressure setting unit configured to set a pressure of the anode gas higher when the load is high as compared with when the load is low, a stagnation point determination unit configured to determine, according to a state of power generation of the fuel cell stack, whether or not a nitrogen stagnation point is left in a reaction flow path within the fuel cell stack, and an operation control unit configured to performs an operation while preventing the pressure of the anode gas from being lowered when a required load is lowered in a state where the nitrogen stagnation point is left.

Abstract: A fuel cell system includes: a coolant circulation passage through which a coolant for cooling a fuel cell circulates; a pump that circulates the coolant; a radiation unit that cools the coolant by discharging heat from the coolant; a bypass passage connected to the coolant circulation passage so as to bypass the radiation unit; and an open/close valve that is provided in a convergence portion where low temperature coolant that has passed through the radiation unit and high temperature coolant that has passed through the bypass passage without passing through the radiation unit converge, and that opens when a temperature of the high temperature coolant reaches or exceeds a predetermined opening temperature, whereby the low temperature coolant and the high temperature coolant converge and are supplied thus to the fuel cell, wherein a basic discharge flow of the pump is calculated in accordance with a condition of the fuel cell, and when the temperature of the low temperature coolant is lower than a predetermin

Abstract: Deterioration at the start-up and deterioration during the leaving period are suppressed in a good balance. As a system shutdown process, a controller (30) causes consumption of the air (oxygen) present in an oxidant electrode of a fuel cell stack (1) (oxygen consumption control). Further, after the termination of the oxygen consumption control, the controller (30) performs control to set a medium pressure hydrogen valve (13) and a hydrogen pressure adjustment valve (14) in a closed state. The controller (30) thereby causes hydrogen to be held in a passage located between the medium pressure hydrogen valve (13) and the hydrogen pressure adjustment valve (14). During a system shutdown period, a predetermined amount of hydrogen (medium pressure hydrogen) held in the hydrogen supply passage (L1) at a position between the medium pressure hydrogen valve (13) and the hydrogen pressure adjustment valve (14) can be supplied to the fuel electrode of the fuel cell stack (1) through a bypass passage (L2).