Abstract: A straddled vehicle, including: an engine, which includes a combustion chamber; a three-way catalyst, which is configured to purify exhaust gas exhausted from the combustion chamber; an upstream oxygen sensor, which is provided upstream of the three-way catalyst in a flow direction of the exhaust gas, and is configured to detect an oxygen concentration in the exhaust gas; a downstream oxygen sensor, which is provided downstream of the three-way catalyst in the flow direction of the exhaust gas, and is configured to detect the oxygen concentration in the exhaust gas; and a controller, which includes a processor, and a non-transitory storage medium containing program instructions, execution of which by the processor causes the controller to execute a detachment determination process of determining whether the three-way catalyst is detached at least based on a signal input as a signal of the downstream oxygen sensor.

Abstract: A fuel cell system includes a removal treatment execution unit configured to execute an oxide layer removal treatment that removes an oxide layer generated on a catalyst of a fuel cell. The removal treatment execution unit is configured to execute the oxide layer removal treatment by adjusting a voltage of the fuel cell to be within a predetermined second voltage range lower than a predetermined first voltage range that is lower than an open-circuit voltage, when an operation of the fuel cell system shifts from a first operation, where a current value of the fuel cell is zero and the flow rate is controlled to maintain the voltage of the fuel cell within the first voltage range, to a second operation, where the current value is larger than zero and the flow rate is controlled in response to an output request to the fuel cell.

Abstract: A fuel cell system includes a controller configured to execute refreshing control for removing an oxide film on a catalyst during an operation of a fuel cell, and an impedance measurer configured to measure an impedance of the fuel cell during the operation of the fuel cell. The impedance measurer executes a calculation process for calculating the impedance by using measurement values of a current and a voltage of the fuel cell in a predetermined measurement time, and outputs a substitute value prepared in advance as the impedance when the start of the refreshing control during the measurement time is detected.

Abstract: A fuel cell system includes: a flow sensor configured to measure an actual flow rate of air which is introduced into an oxidizing gas supply passage via a compressor when a fuel cell generates electric power; and a wind speed deriving unit configured to acquire a flow rate of air measured by the flow sensor in a state in which air flows from the oxidizing gas supply passage to an oxidizing gas discharge passage via the compressor and a bypass flow passage and to derive an actual wind speed of wind which is received by the fuel cell system, when the compressor stops.

Abstract: When electric power requested from a load exceeds a predetermined reference value, an operating state of the fuel cell system is controlled so as to enable a normal operation mode where the fuel cell generates electric power corresponding to the requested electric power. When the requested electric power is the reference value or less, the operating state is controlled to enable an intermittent operation mode. A refresh process for sweeping current from the fuel cell and lowering the voltage of the fuel cell to a reduction voltage is executed during a shift from the intermittent operation mode to the normal operation mode. The current swept from the fuel cell at the start of the refresh process is reduced more as an oxygen amount in the fuel cell at the end of the intermittent operation mode is smaller.

Abstract: A device for monitoring electricity generation comprising: an acquirer that acquires a total value of cell voltage from multiple cells including fuel cells; an increaser that increases the anode gas now rate to the multiple cells when the total value shows a possibility of negative voltage occurring in some of the multiple cells; and a judger that judges if negative voltage occurred in some of the multiple cells based on the total value following the increase of the anode gas flow rate.

Abstract: A fuel cell system includes a removal treatment execution unit configured to execute an oxide layer removal treatment that removes an oxide layer generated on a catalyst of a fuel cell. The removal treatment execution unit is configured to execute the oxide layer removal treatment by adjusting a voltage of the fuel cell to be within a predetermined second voltage range lower than a predetermined first voltage range that is lower than an open-circuit voltage, when an operation of the fuel cell system shifts from a first operation, where a current value of the fuel cell is zero and the flow rate is controlled to maintain the voltage of the fuel cell within the first voltage range, to a second operation, where the current value is larger than zero and the flow rate is controlled in response to an output request to the fuel cell.

Abstract: A fuel cell system includes: a flow sensor configured to measure an actual flow rate of air which is introduced into an oxidizing gas supply passage via a compressor when a fuel cell generates electric power; and a wind speed deriving unit configured to acquire a flow rate of air measured by the flow sensor in a state in which air flows from the oxidizing gas supply passage to an oxidizing gas discharge passage via the compressor and a bypass flow passage and to derive an actual wind speed of wind which is received by the fuel cell system, when the compressor stops.

Abstract: At an ordinary stop time of a fuel cell system, a controller of the fuel cell system completes an ordinary stop process that includes at least one of a water drainage process that discharges water from at least one of the fuel gas flow path and the oxidizing gas flow path and a cathode sealing process that seals the oxidizing gas flow path, and subsequently stops the fuel cell system. When the fuel cell system satisfies a predetermined emergency stop condition, the controller does not perform at least part of the ordinary stop process but performs an emergency stop process that sets the fuel cell system to be restarted after elapse of a first time period since a stop of the fuel cell system and subsequently stops the fuel cell system. The controller restarts the fuel cell system after elapse of the first time period since stop of the fuel cell system and performs a restart process that performs the ordinary stop process.

Abstract: A fuel cell system, comprising: a measurer that measures an impedance of the fuel cell; a controller that controls an operation state of the fuel cell; and an acquirer that acquires a dryness degree of the fuel cell from the measured impedance when the operation state is a first operation state, and acquires the dryness degree of the fuel cell as a wet state when the operation state is a second operation state in which a water balance is more than the first operation state.

Abstract: A fuel cell system comprising: an acquirer that acquires a total value of cell voltages of two or more cells included in a fuel cell; and a determiner that determines, when the total value is a first voltage value, abnormal power generation in which power generation by at least a part of the two or more cells is abnormal, that determines, when the total value is a second voltage value higher than the first voltage value, normal power generation in which power generation by the two or more cells is normal and that determines, when the total value is a third voltage value higher than the first voltage value but lower than the second voltage value, the normal power generation if a cathode gas is deficient or the abnormal power generation if the cathode gas is not deficient.

Abstract: A fuel cell system includes a fuel cell including an electrolyte membrane, a sensor configured to measure a temperature of the fuel cell, and a controller. The controller is configured to cause the fuel cell to perform a wet operation to increase a water balance at a cathode of the fuel cell to a value higher than a water balance at the cathode during a normal operation of the fuel cell, when the temperature of the fuel cell measured by the sensor is maintained at a first threshold temperature or higher for a prescribed period of time or longer and then the temperature of the fuel cell decreases to below a second threshold temperature that is equal to or lower than the first threshold temperature.

Abstract: The fuel cell system includes: a fuel cell 40 that receives supply of reactant gas to generate power; output characteristic updating means for updating an output characteristic of the fuel cell 40 based on output current and output voltage measured by a current sensor 140 and a voltage sensor 150; maximum power calculation means for calculating, using the output characteristic, the maximum power available at the fuel cell 40; and determination means for determining whether a value of the output characteristic is in an assumed situation where the output characteristic value is assumed to be temporarily lowered, wherein while the output characteristic value is determined by the determination means to be in the assumed situation, the maximum power calculation means calculates the maximum power using the output characteristic updated by the output characteristic updating means just before transition to the assumed situation.

Abstract: At an ordinary stop time of a fuel cell system, a controller of the fuel cell system completes an ordinary stop process that includes at least one of a water drainage process that discharges water from at least one of the fuel gas flow path and the oxidizing gas flow path and a cathode sealing process that seals the oxidizing gas flow path, and subsequently stops the fuel cell system. When the fuel cell system satisfies a predetermined emergency stop condition, the controller does not perform at least part of the ordinary stop process but performs an emergency stop process that sets the fuel cell system to be restarted after elapse of a first time period since a stop of the fuel cell system and subsequently stops the fuel cell system. The controller restarts the fuel cell system after elapse of the first time period since stop of the fuel cell system and performs a restart process that performs the ordinary stop process.

Abstract: A fuel cell system includes a fuel cell including an electrolyte membrane, a sensor configured to measure a temperature of the fuel cell, and a controller. The controller is configured to cause the fuel cell to perform a wet operation to increase a water balance at a cathode of the fuel cell to a value higher than a water balance at the cathode during a normal operation of the fuel cell, when the temperature of the fuel cell measured by the sensor is maintained at a first threshold temperature or higher for a prescribed period of time or longer and then the temperature of the fuel cell decreases to below a second threshold temperature that is equal to or lower than the first threshold temperature.

Abstract: A fuel cell system, comprising: a measurer that measures an impedance of the fuel cell; a controller that controls an operation state of the fuel cell; and an acquirer that acquires a dryness degree of the fuel cell from the measured impedance when the operation state is a first operation state, and acquires the dryness degree of the fuel cell as a wet state when the operation state is a second operation state in which a water balance is more than the first operation state.

Abstract: An amount of power generation is increased in the case where a difference in water content between some and others of the cells is greater than a predetermined value. In the case of satisfaction of a first condition that the difference in water content between some and others of the cells is greater than the predetermined value, a fuel battery may be caused to perform an operation in which the amount of power generation exceeds that in the normal operation to reduce a cell voltage difference ?V between an average cell voltage Va and a minimum cell voltage Vb. The first condition is, for example, that the cell voltage difference ?V, which is a difference between the average cell voltage Va and the minimum cell voltage Vb, is greater than a first threshold value.

Abstract: A fuel cell system comprising: an acquirer that acquires a total value of cell voltages of two or more cells included in a fuel cell; and a determiner that determines, when the total value is a first voltage value, abnormal power generation in which power generation by at least a part of the two or more cells is abnormal, that determines, when the total value is a second voltage value higher than the first voltage value, normal power generation in which power generation by the two or more cells is normal and that determines, when the total value is a third voltage value higher than the first voltage value but lower than the second voltage value, the normal power generation if a cathode gas is deficient or the abnormal power generation if the cathode gas is not deficient.

Abstract: The fuel cell system includes: a fuel cell 40 that receives supply of reactant gas to generate power; output characteristic updating means for updating an output characteristic of the fuel cell 40 based on output current and output voltage measured by a current sensor 140 and a voltage sensor 150; maximum power calculation means for calculating, using the output characteristic, the maximum power available at the fuel cell 40; and determination means for determining whether a value of the output characteristic is in an assumed situation where the output characteristic value is assumed to be temporarily lowered, wherein while the output characteristic value is determined by the determination means to be in the assumed situation, the maximum power calculation means calculates the maximum power using the output characteristic updated by the output characteristic updating means just before transition to the assumed situation.

Abstract: A device for monitoring electricity generation comprising: an acquirer that acquires a total value of cell voltage from multiple cells including fuel cells; an increaser that increases the anode gas now rate to the multiple cells when the total value shows a possibility of negative voltage occurring in some of the multiple cells; and a judger that judges if negative voltage occurred in some of the multiple cells based on the total value following the increase of the anode gas flow rate.