Abstract: The present invention provides a technique capable of satisfying both the restoration of an output voltage of a fuel cell and an improvement of electric power responsiveness in a fuel cell system in a situation in which its operation status is restored to a normal operation from an operation having low power generation efficiency. A controller updates a lower limit voltage threshold in accordance with the restoration of an FC voltage until the operation status is restored to a normal operation from an operation having low power generation efficiency, such as an intermittent operation and a warmup operation (step S1). The controller increases an FC current in accordance with the updated lower limit voltage threshold (steps S2 and S3) to thereby satisfy both the requirements of the restoration of the output voltage of the fuel cell stack and the improvement of the electric power responsiveness.

Abstract: The present invention provides a fuel cell system capable of suppressing the accumulation of impurities in a hydrogen system even when a hydrogen pump stops. A fuel cell system 100 includes a hydrogen pump 4, which is provided in a hydrogen gas circulation flow path 3 and which circulates a hydrogen off-gas discharged from the outlet side of a hydrogen electrode 1a of a fuel cell 1 to the inlet side of the hydrogen electrode 1a, a discharge valve 61, through which the hydrogen off-gas flowing in the hydrogen gas circulation flow path 3 is discharged out of the hydrogen gas circulation flow path 3, a determination section 81, which determines whether the hydrogen pump 4 is stopped, and a control unit 80, which controls the opening/closing of the discharge valve 61.

Abstract: A fuel cell system includes: a fuel cell; a fuel gas path supplied with fuel and allowing a part of fuel gas discharged from the fuel cell to circulate; an exhaust mechanism discharging the reacted fuel gas to an outside; a circulation mechanism circulating the fuel gas; and a control unit configured to temporarily stop circulation of the fuel gas by the circulation mechanism when determining that discharge from the exhaust mechanism is not normal, drive the circulation mechanism so that the fuel gas circulates at a first circulation speed when determining that the discharge is not normal and a parameter relating to water vapor in the fuel gas path is equal to a predetermined value or greater, and drive the circulation mechanism so that the fuel gas circulates at a second circulation speed greater than the first circulation speed when determining that the discharge is normal.

Abstract: An objection is to provide a technology by which a decline in the starting performance of a fuel cell system may be controlled in a low-temperature environment. A control method of a fuel cell system includes a temperature acquisition step of acquiring a temperature of the fuel cell at start-up of the fuel cell; and an exhaust gas control step of restricting, when the temperature of the fuel cell is below a predetermined value, a flow rate of an exhaust gas flowing into a flow path configuring portion that configures at least a part of a flow path of the exhaust gas of the fuel cell as compared to the flow rate of the exhaust gas flowing into the flow path configuring portion when the temperature of the fuel cell is equal to or less than the predetermined value.

Abstract: A valve control apparatus controls a valve for adjusting a pressure of a reaction gas supplied to a fuel cell. The valve control apparatus includes: an estimation portion that estimates a valve effective cross-sectional area of the valve; and an opening adjustment portion that adjusts opening degree of the valve with control amount corrected based on the valve effective cross-sectional area estimated by the estimation portion.

Abstract: An object is to provide a technique that a current state of a fuel cell may be detected more accurately. A fuel cell system includes a controller, a fuel cell, and an impedance measurer that may measure an impedance of the fuel cell. The controller obtains a first impedance value that expresses the impedance of the fuel cell in a predetermined state, acquires a second impedance value that expresses the impedance of the fuel cell that is measured by the impedance measurer during operation control of the fuel cell, and performs operation control of the fuel cell using the first impedance value and the second impedance value.

Abstract: There is provided a fuel cell system, wherein a controller configured to set the flow volume of a fluid in an anode flow path at an outlet of an anode of the fuel cell to a first flow volume, then set thereafter the flow volume of the fluid in the anode flow path at the outlet of the anode to a second flow volume which is smaller than the first flow volume, and discharge the water in the hydrogen discharge flow path by opening an exhaust and drain valve while the fluid is flowing at the second flow volume.

Abstract: A fuel cell system comprises: a fuel cell; a cooling liquid supply flow path for supplying cooling liquid to the fuel cell; a radiator for cooling the cooling liquid; a first temperature sensor, provided at an outlet of the radiator, for measuring a temperature of the cooling liquid; an ambient temperature sensor; and a controller. The controller executes: estimating a temperature of the cooling liquid inside the cooling liquid supply flow path based on an ambient temperature measured by the ambient temperature sensor; acquiring a temperature of the cooling liquid inside the cooling liquid supply flow path based on the temperature measured by the first temperature sensor after it is determined that the cooling liquid within the radiator has reached the first temperature sensor; and adjusting a flow rate of the cooling liquid based on the estimated temperature or the acquired temperature of the cooling liquid.

Abstract: An object is to provide a technique that suppresses excessive water drainage from a fuel cell. A water drainage device for fuel cell that drains water from inside of a fuel cell, includes: a purge gas supply system; an operation unit; a water drainage controller; and a water content acquirer. The operation unit receives a water drainage command from a user to give an instruction of purging out water from inside of the fuel cell by the purge gas supply system. When the water content obtained by the water content acquirer is equal to or lower than a predetermined value, the water drainage controller performs either one of: (i) a process of invalidating the water drainage command received by the operation unit; and (ii) a process of changing a processing condition of the purge process to decrease an amount of water drained by the purge process, compared with an amount of water drainage when the obtained water content is higher than the predetermined value.

Abstract: To provide technology that is capable of inhibiting a decrease in starting properties of a pump in a low-temperature environment. A fuel cell system is equipped with a control unit, a fuel cell, and a pump. The control unit acquires the temperature of the fuel cell as a parameter expressing the temperature of the pump while operation of the fuel cell is stopped. The control unit rotates rotation body of the pump when it is detected that the temperature of the pump is a threshold value or less set within a predetermined range lower than the freezing point based on the detected temperature of the fuel cell.

Abstract: The present invention enables the determination of an operating point of a fuel cell so as to prioritize the fulfillment of an amount of required power generation while avoiding various limitations, such as a current limit, in a fuel cell system that warms up the fuel cell by a low efficiency operation. A controller 70 multiplies a voltage command value Vcom obtained in step S3 by a current command value Icom obtained in step S1, then, this is divided by a final voltage command value Vfcom obtained in step S4, thereby obtaining a final current command value Ifcom to determine an operating point (Ifcom, Vfcom) during a warm-up operation (step S5), and then the process ends.

Abstract: A fuel cell system 10 includes a fuel cell 20, gas supply systems 30, 40, which supply gases to the fuel cell 20, and a controller 60, which controls the gas supply systems 30, 40. During a non-operation period of the fuel cell 20, the controller 60 controls the gas supply systems 30, 40 to carry out the scavenging treatment. If the scavenging treatment is interrupted by an operation performed by a user, then the controller 60 controls the gas supply systems 30, 40 and restarts the scavenging treatment after a predetermined time elapses from the interruption.

Abstract: The problem is that a large force is required to open a flow-dividing shut valve provided in an air supply path for supplying the air to a fuel cell stack at a start of a fuel cell system. This problem is solved by reducing a pressure difference between upstream and downstream of the flow-dividing shut valve, before the flow-dividing shut valve is opened, at a start of the fuel cell system.

Abstract: The method comprises: determining whether or not an inlet temperature is equal to or above a lower-limit temperature of a temperature range in which generated water does not freeze within the fuel cell; and adjusting the flow rate of the cooling medium in the circulation flow path to become more than the normal flow rate when it is determined that the inlet temperature is equal to or above the lower-limit temperature, and adjusting the flow rate of the cooling medium in the circulation flow path to be equal to or below the normal flow rate when it is determined that the inlet temperature is not equal to or above the lower-limit temperature.

Abstract: A method includes predicting, while fuel cell system is operated, whether or not the outside temperature becomes equal to or less than a first predetermined temperature; performing, when it is predicted that the outside temperature becomes equal to or less than the first predetermined temperature, residual water scavenging processing on only an oxidizer gas supply/discharge mechanism and thereafter stopping the operation of the fuel cell system; predicting, after the stop of the operation of the fuel cell system, whether or not the temperature of a predetermined component included in the fuel cell system becomes equal to or less than a second predetermined temperature; and performing the residual water scavenging processing on the fuel gas supply/discharge mechanism when it is predicted that the temperature of the predetermined component becomes equal to or less than the second predetermined temperature.

Abstract: The operation control method of a fuel cell includes acquiring a startup temperature of the fuel cell; acquiring a present temperature of the fuel cell; setting a present target operation point of the fuel cell that is identified by an output voltage value and an output current value based on the startup temperature, or based on the startup temperature and the present temperature; controlling at least one of the flow of the reaction gas supplied to the fuel cell, and an output voltage of the fuel cell so that the operation point of the fuel cell becomes the target operation point, and setting the target operation point includes a process of setting an operation point having a low output voltage value as the target operation point when the startup temperature is low as compared to the case when the startup temperature is high, if the present temperature is the same.

Abstract: A fuel cell system includes: a fuel cell outputting a current; a supply unit supplying oxidant gas; a flow-amount measurement unit measuring a flow amount of the oxidant gas; and a controller that feed-back controls the supply unit such that a measured flow-amount value converges toward a target flow-amount value, wherein the controller determines an acceptable current value in accordance with the measured flow-amount value, restricts the current to the acceptable current value or less, controls the current in accordance with a requested current value of the fuel cell; and performs a changing-suppression processing, when a condition continues for a predetermined period, the condition including that a changing width of the requested current value is equal to or less than a first value and a difference between the requested current value and the acceptable current value is equal to or less than a second value.

Abstract: The problem is that a large force is required to open a flow-dividing shut valve provided in an air supply path for supplying the air to a fuel cell stack at a start of a fuel cell system. This problem is solved by reducing a pressure difference between upstream and downstream of the flow-dividing shut valve, before the flow-dividing shut valve is opened, at a start of the fuel cell system.

Abstract: A hydrogen tank is mounted on a roof so that a valve unit mounted to one end in a longitudinal direction of the hydrogen tank is separated as far apart as possible from a front platform and a middle platform of a fuel cell equipped bus and so that the longitudinal direction of the hydrogen tank is in a lateral direction of a vehicle. Thus, even if hydrogen leaks from the valve unit or a fusible plug valve of the valve unit is fused to discharge hydrogen from the tank, the influence of the leaking or discharged hydrogen on the front platform and the middle platform can be reduced.

Abstract: If a required voltage which corresponds to a required power has reached a boundary voltage, which is an oxidation-reduction potential of platinum, which constitutes a catalyst of a fuel cell, the fuel cell system performs crossover-avoidance control that holds an FC instruction voltage for the fuel cell at the boundary voltage, and absorbs the gap between the required voltage and the FC instruction voltage by using a secondary battery.