JP4613694B2 - Fuel cell vehicle and control method thereof - Google Patents

Description

  The present invention relates to a fuel cell vehicle and a control method thereof.

Conventionally, a fuel cell vehicle equipped with a fuel cell is known. This type of fuel cell vehicle includes a motor that rotates the wheel, a fuel cell that can supply the motor with the electric energy generated by the electrochemical reaction between the fuel gas and the oxidizing gas, and the discharged electric energy. And a power storage means that can be supplied to the motor. For example, Patent Document 1 includes a drive motor, a fuel cell, and a capacitor as a power storage unit, and determines whether or not idle stop is possible based on whether or not the required power is a predetermined value or less. When possible, the compressor that supplies air as oxidizing gas to the fuel cell is stopped to stop the power generation operation of the fuel cell, and the power supply to the drive motor is performed by the capacitor. A fuel cell vehicle that controls the output of a battery is disclosed. In Patent Document 1, when it is determined that the required power exceeds a predetermined value during the idle stop, for example, it is determined that the idle stop is not possible, the fuel cell in the power generation stop is restarted.
JP-A-2004-56868

  However, in Patent Document 1, in order to restart the fuel cell in the power generation operation stop, it is necessary to satisfy the condition that the required power exceeds a predetermined value, but the predetermined value at this time is Because it is always constant, for example, when the power generation performance of the fuel cell is deteriorated or when the charge amount of the capacitor is insufficient, it takes a long time to output the power required by the driver, etc. A phenomenon may occur.

  The present invention has been made to solve such a problem, and in a fuel cell vehicle for stopping and restarting a fuel cell and a control method thereof, a vehicle after restarting a fuel cell that has stopped power generation operation. It aims at suppressing that the motive power performance falls.

  The present invention adopts the following means in order to achieve the above-mentioned object.

The fuel cell vehicle of the present invention is
An electric energy consuming device mounted on a vehicle;
A fuel cell capable of supplying electric energy generated by an electrochemical reaction between a fuel gas and an oxidizing gas to the electric energy consuming device;
Power storage means capable of discharging charged electric energy and supplying the electric energy consuming device;
Electric energy supply control means for supplying electric energy of either one or both of the fuel cell and the power storage means to the electric energy consuming device based on a running state;
A predetermined restart condition including stopping the power generation operation of the fuel cell when a predetermined stop condition is satisfied, and the electric energy required for the vehicle during the stop of the power generation operation of the fuel cell exceeding a predetermined threshold A stop / restart control means for restarting the power generation operation of the fuel cell when
Threshold changing means for changing the threshold based on a parameter related to at least one of the fuel cell and the power storage means;
It is equipped with.

  In this fuel cell vehicle, the electric energy consuming device consumes the electric energy by supplying the electric energy consuming device with the electric energy of one or both of the fuel cell and the power storage means based on the running state. In addition, when the predetermined stop condition is satisfied, the fuel cell power generation operation is stopped, and the predetermined restart condition includes that the electric energy required for the vehicle during the fuel cell power generation operation stop exceeds a predetermined threshold value. When is established, the power generation operation of the fuel cell is restarted. Here, the threshold value included in the restart condition is changed based on a parameter related to at least one of the fuel cell and the power storage means. For this reason, for example, when the state of the fuel cell is not good or the state of the power storage means is not good, the electric energy from the fuel cell is reduced by lowering the threshold value and restarting the fuel cell in the power generation operation stop early. Electric energy can be supplied to the consuming device at an early stage. Therefore, it is possible to suppress a reduction in the power performance of the vehicle after restarting the fuel cell in which the power generation operation is stopped.

  Here, the “electric energy consuming device” is not particularly limited as long as it consumes electric energy. For example, motors for driving wheels, auxiliary devices for fuel cells (air compressors, hydrogen circulation pumps, etc.) ), One or more of electric steering, electric brake, air conditioner and the like.

  In the fuel cell vehicle according to the present invention, the threshold value changing unit may change the threshold value based on electric energy that can be discharged from the power storage unit. Here, the threshold value changing means may change the threshold value to a value lower than the normal time when the dischargeable electric energy of the power storage means is lower than the normal time. In this way, when the electric energy that can be discharged by the power storage means is lower than normal, the fuel cell that has stopped generating power restarts and starts supplying electric energy to the electric energy consuming device earlier than normal. Therefore, since the fuel cell replenishes insufficient electrical energy at an early stage, it is possible to suppress a decrease in power performance. The threshold value may be changed stepwise with respect to the electric energy that can be discharged by the power storage means, or may be changed continuously.

  In the fuel cell vehicle according to the present invention, the threshold value changing means may change the threshold value based on a current-voltage characteristic of the fuel cell. Here, the threshold value changing means may change the threshold value to a value lower than the normal time when the current-voltage characteristic of the fuel cell is deteriorated compared to the normal time. In this way, when the current-voltage characteristic of the fuel cell is deteriorated compared to the normal time, the fuel cell in the power generation operation stop is restarted and the timing to start supplying electric energy to the electric energy consuming device is higher than the normal time. Since the fuel cell itself can compensate for the deteriorated current-voltage characteristics of the fuel cell, it is possible to suppress a decrease in power performance. Since the product of the current and voltage of the fuel cell is the generated power, the current-voltage characteristic of the fuel cell can be said to be an indicator of the power generation capability of the fuel cell. The current-voltage characteristic of the fuel cell may be obtained using the current value and voltage value of the fuel cell immediately before stopping the power generation operation. Note that the threshold value may be changed stepwise or continuously with respect to the current-voltage characteristic of the fuel cell.

  The fuel cell vehicle of the present invention includes a voltage adjusting unit that is interposed between the power storage unit and the electric energy consuming device and adjusts an operating point of the fuel cell, and an electric energy that can pass through the voltage adjusting unit. Passing energy setting means for setting based on the state of the adjusting means, and the threshold value changing means may change the threshold value based on the electrical energy set by the passing energy setting means. The electric energy that can pass through the voltage adjusting means can be regarded as electric energy supplied from the power storage means to the electric energy consuming device. Here, the threshold value changing means may change the threshold value to a value lower than the normal time when the electric energy that can pass through the voltage adjusting means is limited as compared with the normal time. In this way, when the electric energy that can pass through the voltage adjusting means is lower than normal, the time when the fuel cell in the power generation operation stop restarts and starts supplying electric energy to the electric energy consuming device is lower than normal. Since the fuel cell is replenished early because the electrical energy is insufficient, it is possible to suppress a decrease in power performance. The threshold value may be changed stepwise with respect to the electric energy that can pass through the voltage adjusting means, or may be changed continuously.

  The fuel cell vehicle of the present invention includes an oxidizing gas supply means for sucking outside air and supplying the outside air as the oxidizing gas to the fuel cell, and the threshold value changing means changes the threshold value based on the pressure of the outside air. May be. When the outside air pressure is low and when the outside air pressure is high, even if the suction operation of the oxidizing gas supply means is the same, the substantial amount of oxidizing gas supply is lower when the pressure of the outside air pressure is lower than when it is higher. Therefore, it is meaningful to change the timing at which the fuel cell in which the power generation operation is stopped restarts based on the pressure of the outside air (and thus the timing at which electric energy is started to be supplied from the fuel cell to the electric energy consuming device). Here, the threshold value changing means may change the threshold value to a value lower than normal when the pressure of the outside air is lower than normal. In this way, when the outside air pressure is low and the substantial outside air intake amount is small, the time when the fuel cell in the power generation operation stop is restarted to start supplying electric energy to the electric energy consuming device is earlier than usual. Therefore, since the fuel cell replenishes the electrical energy that is deficient with a decrease in the supply amount of the oxidizing gas at an early stage, it is possible to suppress a decrease in power performance. Note that the threshold value may be changed stepwise or continuously with respect to the pressure of the outside air.

The fuel cell vehicle control method of the present invention includes:
An electric energy consuming device for rotating the wheel; a fuel cell capable of supplying electric energy generated by an electrochemical reaction between fuel gas and oxidizing gas to the electric energy consuming device; and discharging the charged electric energy to discharge the electric energy A method for controlling a fuel cell vehicle comprising a power storage means capable of being supplied to an electric energy consuming device,
At the time of traveling, the electric energy of either one or both of the fuel cell and the power storage means is supplied to the electric energy consuming device based on the traveling state, and the power generation operation of the fuel cell is performed when a predetermined fuel cell stop condition is satisfied. Stops and restarts the power generation operation of the fuel cell when a predetermined fuel cell restart condition is satisfied, including that the electric energy required for the vehicle exceeds a predetermined threshold while the fuel cell power generation operation is stopped Then, before the restart, the threshold value is changed based on a parameter related to at least one of the fuel cell and the power storage means.

  In this fuel cell vehicle control method, the threshold value included in the restart condition is changed based on a parameter related to at least one of the fuel cell and the power storage means. For this reason, for example, when the state of the fuel cell is not good or the state of the power storage means is not good, the electric energy from the fuel cell is reduced by lowering the threshold value and restarting the fuel cell in the power generation operation stop early. Electric energy can be supplied to the consuming device at an early stage. Therefore, it is possible to suppress a reduction in the power performance of the vehicle after restarting the fuel cell in which the power generation operation is stopped. Note that steps for realizing the functions of various means included in any of the fuel cell vehicles described above may be added to the control method of the fuel cell vehicle.

  Next, the best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of the configuration of a fuel cell vehicle 10 representing an example of the present invention, FIG. 2 is a cross-sectional view showing an outline of the configuration of a fuel cell 40, and FIG. It is a circuit diagram.

  The fuel cell vehicle 10 includes a fuel cell stack 30 in which a plurality of fuel cells 40 that generate electricity by an electrochemical reaction between hydrogen as a fuel gas and oxygen in the air as an oxidizing gas are stacked, and the fuel cell stack 30 and an inverter 54. , A battery 58 connected via a DC / DC converter 56 to a power line 53 connecting the inverter 54 and the fuel cell stack 30, and an electronic control unit 70 for controlling the entire system. It has. The drive shaft 64 is connected to the drive wheels 63 and 63 via the differential gear 62, and the power output from the motor 52 is finally output to the drive wheels 63 and 63 via the drive shaft 64. It is like that.

  The fuel cell stack 30 is formed by stacking a plurality (for example, several hundreds) of polymer electrolyte fuel cells 40. As shown in FIG. 2, the fuel cell 40 includes a solid electrolyte membrane 42, which is a proton conductive membrane formed of a polymer material such as a fluororesin, and a catalyst of platinum or an alloy made of platinum and other metals. The anode 43 and the cathode 44 as gas diffusion electrodes that sandwich the solid electrolyte membrane 42 on the surface formed by the carbon cloth in which the catalyst is kneaded and sandwich the sandwich structure, and sandwich the sandwich structure from both sides The fuel gas flow path 46 is formed between the anode 43 and the oxidant gas flow path 47 between the cathode 44 and the two separators 45 forming a partition wall with the adjacent fuel cell 40. ing. Then, hydrogen as the fuel gas passing through the fuel gas channel 46 is diffused in the anode 43 and separated into protons and electrons by the catalyst. Among them, protons are transferred to the cathode 44 through the wet solid electrolyte membrane 42, and electrons move to the cathode 44 through an external circuit. Further, oxygen contained in the air as the oxidizing gas that passes through the oxidizing gas channel 47 is diffused by the cathode 44, and protons, electrons, and oxygen in the air react on the catalyst to generate water. Due to the above electrochemical reaction, an electromotive force is generated in each fuel cell 40 to generate electric energy. Further, an ammeter 31 and a voltmeter 33 are attached to the fuel cell stack 30, the ammeter 31 detects a current output from the fuel cell stack 30, and the voltmeter 33 is output from the fuel cell stack 30. The voltage is detected.

  The fuel cell stack 30 is provided with a hydrogen cylinder 12 for supplying hydrogen and an air compressor 22 for sucking outside air and feeding it. The hydrogen cylinder 12 stores high-pressure hydrogen of several tens of MPa, and supplies hydrogen adjusted in pressure by the regulator 14 to the fuel cell stack 30. The hydrogen supplied to the fuel cell stack 30 passes through the fuel gas passage 46 (see FIG. 2) of each fuel cell 40 and then is led out to the fuel gas discharge pipe 32. An anode purge valve 18 used for increasing the hydrogen concentration in the fuel cell stack 30 is attached to the fuel gas discharge pipe 32. The hydrogen concentration in the fuel gas flow path 46 shown in FIG. 2 decreases as nitrogen in the air in the oxidizing gas flow path 47 flows into the anode 43 side, so that the anode purge is performed for a predetermined open time every predetermined interval. The valve 18 is opened to expel nitrogen in the fuel gas passage 46. The hydrogen circulation pump 20 also supplies the hydrogen-containing gas in the fuel gas discharge pipe 32 from between the fuel cell stack 30 and the anode purge valve 18 in the fuel gas discharge pipe 32 to between the fuel cell stack 30 and the regulator 14. The hydrogen supply amount can be adjusted by changing the rotation speed.

  On the other hand, the air compressor 22 pressure-feeds air sucked from the atmosphere through an air cleaner (not shown) to the fuel cell stack 30, and the oxygen supply amount can be adjusted by changing the rotation speed. A humidifier 24 is provided between the air compressor 22 and the fuel cell stack 30, and the humidifier 24 humidifies the air fed by the air compressor 22 and supplies it to the fuel cell stack 30. The air supplied to the fuel cell stack 30 passes through the oxidizing gas passage 47 (see FIG. 2) of each fuel cell 40 and is then discharged from the oxidizing gas discharge pipe 34. An air pressure regulating valve 26 is provided in the oxidizing gas discharge pipe 34, and the pressure in the oxidizing gas flow path 47 is adjusted by the air pressure regulating valve 26. Note that the air discharged from the fuel cell stack 30 to the oxidizing gas discharge pipe 34 is humid due to water generated by the electrochemical reaction, but the humidifier 24 is an air pumped from the air compressor 22 from this humid air. It plays a role in exchanging water vapor.

  1 are the regulator 14, the anode purge valve 18, the hydrogen circulation pump 20, the air compressor 22, the humidifier 24, the air pressure regulating valve 26, and the like. These are from the fuel cell stack 30 or the battery 58. Receive power supply.

  The motor 52 is connected to a drive shaft 64 and is configured as a well-known synchronous generator motor that can be driven as a generator and can also be driven as an electric motor. A battery 58 and a fuel cell stack are connected via an inverter 54. Exchange power with 30.

  The battery 58 is configured as a well-known nickel hydride secondary battery, and is connected in parallel with the fuel cell stack 30 via a DC / DC converter 56. The battery 58 absorbs regenerative energy at the time of deceleration of the vehicle and electric energy generated in the fuel cell stack 30, or discharges the accumulated electric energy to supply the motor 52 with power that is insufficient only by the fuel cell stack 30. To do. The latter operation is to supply the motor 52 with electric power that is insufficient by the fuel cell stack 30 alone, and is therefore referred to as assist of the fuel cell stack 30 by the battery 58, or simply referred to as battery assist or power assist. A capacitor may be employed instead of the battery 58.

  As shown in FIG. 3, the DC / DC converter 56 boosts and lowers the voltage of the battery 58 by repeatedly storing and discharging energy to and from the reactor 56c by switching of the IGBT power system transistor housed in the step-up IPM 56a. It is. The DC / DC converter 56 serves to adjust the operating point of the fuel cell stack 30. Further, when the temperature of the step-up IPM 56a or the reactor 56c of the DC / DC converter 56 rises excessively, that is, when it overheats, the electric power passing through the DC / DC converter 56 is limited by the electronic control unit 70. The temperature of the step-up IPM 56a and the temperature of the reactor 56c are detected by the IPM temperature sensor 56b and the reactor temperature sensor 56d, respectively, and output to the electronic control unit 70.

  The electronic control unit 70 is configured as a one-chip microprocessor mainly composed of a CPU 72, and includes a ROM 74 that stores a processing program, a RAM 76 that temporarily stores data, and an input / output port (not shown). It has. The electronic control unit 70 includes an output current Ifc and output voltage Vfc of the fuel cell stack 30 detected by the ammeter 31 and the voltmeter 33, and hydrogen supplied to the fuel cell stack 30 from a flow meter and a thermometer (not shown). And signals related to the flow rate and temperature of air, signals related to the operating state of the humidifier 24 and the air compressor 22, signals necessary for controlling the motor 52 (for example, the rotational speed Nm of the motor 52 and the phase current applied to the motor 52, etc. ), A charge / discharge current necessary for managing the battery 58 is input via the input port. Further, the vehicle speed V from the vehicle speed sensor 88, the shift position SP from the shift position sensor 82 that detects the position of the shift lever 81, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake The brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the pedal 85, the IPM temperature sensor 56b of the DC / DC converter 56, the IPM temperature and the reactor temperature from the reactor temperature sensor 56d, etc. are also input via the input port. Is done. On the other hand, from the electronic control unit 70, a drive signal to the air compressor 22, a control signal to the humidifier 24, a control signal to the regulator 14, the anode purge valve 18 and the air pressure regulating valve 26, a control signal to the inverter 54, DC A control signal to the DC converter 56 is output through the output port.

  Next, the operation of the fuel cell vehicle 10 of the embodiment configured as described above will be described. FIG. 4 is a flowchart showing an example of a drive control routine of the fuel cell vehicle 10.

  When this drive control routine is executed, the CPU 72 of the electronic control unit 70 firstly has the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Nm of the motor 52, the ammeter 31. A process for inputting data necessary for control, such as the output current Ifc of the fuel cell stack 30 from, the output voltage Vfc of the fuel cell stack 30 from the voltmeter 33, and the charge / discharge current of the battery 58 is executed (step S100). The CPU 72 calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current of the battery 58, and is output from the current fuel cell stack 30 based on the output current Ifc and output voltage Vfc of the fuel cell stack 30. Power, that is, the current FC output power Pfc is calculated.

  Subsequently, a travel request torque Tdr * to be output to the drive shaft 64 connected to the drive wheels 63 and 63 is set as a torque required for the vehicle based on the input accelerator opening Acc and the vehicle speed V. Based on the travel request torque Tdr *, a travel request power Pdr * to be output to the drive shaft 64 is set (step S110). In the present embodiment, the required travel torque Tdr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required travel torque Tdr * in the ROM 74 as a required torque setting map. When the vehicle speed V is given, the corresponding travel request torque Tdr * is derived and set from the stored map. FIG. 5 shows an example of the travel request torque setting map. The travel request power Pdr * is calculated as a value obtained by multiplying the set travel request torque Tdr * by the rotational speed Ndr of the drive shaft 64. In this embodiment, since the rotation shaft of the motor 52 is directly connected to the drive shaft 64, the rotation speed Ndr of the drive shaft 64 matches the rotation speed Nm of the motor 52.

  Subsequently, the system required power Psys * required for the entire fuel cell vehicle 10 is set (step S120). The system required power Psys * is calculated as the sum of the travel required power Pdr * set previously and the load required power Px * required for the electric load mounted on the fuel cell vehicle 10 other than traveling. Here, the required load power Px * is a sum of required auxiliary power required for operation of auxiliary machinery, required charging power required when the SOC of the battery 58 is reduced, and the like.

  Subsequently, the FC maximum output power Pfcmax that is the upper limit power that can be output from the fuel cell stack 30 and the battery maximum output power Pbmax that is the upper limit power that can be output from the battery 58 are calculated (step S130). The FC maximum output power Pfcmax is calculated on the basis of power-current characteristics (PV characteristics, see FIG. 6) periodically corrected by fluctuation factors such as the temperature of the fuel cell stack 30 and the supply fuel pressure. Battery maximum output power Pbmax is calculated based on the SOC of battery 58. In the present embodiment, the battery maximum output power Pbmax is assumed to be electric energy that can be discharged from the battery 58.

  Subsequently, a power distribution routine for determining how to distribute the system required power Psys * to the fuel cell stack 30 and the battery 58 is executed (step S140). By executing this power distribution routine, the FC required power Pfc * required for the fuel cell stack 30 and the discharge required power Pb * required for the battery 58 are set, which will be described in detail later.

  Subsequently, the operating point of the fuel cell stack 30 is calculated so that the FC required power Pfc * is output from the fuel cell stack 30 (step S150). FIG. 6 is an explanatory diagram showing the characteristics of the fuel cell stack, where (a) shows the PI characteristics and (b) shows the IV characteristics. The operating point of the fuel cell stack 30 is calculated by first determining the target current Ifc * for outputting the FC required power Pfc * from the PI characteristics shown in FIG. 6A, and then FIG. 6B. The target voltage Vfc * corresponding to the target current Ifc * is determined from the IV characteristics shown in FIG. Then, PI control is performed so that the voltage on the output side of the DC / DC converter 56 becomes the target voltage Vfc *, and the rotational speed of the air compressor 22 is set so that the FC required power Pfc * is output from the fuel cell stack 30. The opening degree of the air pressure regulating valve 26 is controlled (step S160). As a result, the power corresponding to the FC required power Pfc * is output from the fuel cell stack 30 to the inverter 54. When the FC required power Pc * is zero, the power generation operation of the fuel cell stack 30 is stopped. That is, by stopping the rotation of the air compressor 22 and closing the air pressure regulating valve 26, the supply of air to the fuel cell stack 30 is stopped, and the regulator 14 and the anode purge valve 18 are closed to supply the fuel cell stack 30. Hydrogen supply is also stopped.

  Subsequently, a torque command Tm * for the motor 52 is set (step S170). The torque command Tm * is set to a torque value corresponding to the travel request power Pdr * when the travel request power Pdr * can be output from the fuel cell stack 30 and the battery 58 to the motor 52, and the travel request power Pdr * is set to the motor. If the torque cannot be output to 52, the torque value is set within a possible output range. Then, switching control of the inverter 54 is executed so that the torque of the set torque command Tm * is output from the motor 52 (step S180), and this drive control routine is ended.

  Next, the power distribution routine in step S140 will be described in detail. FIG. 7 is a flowchart showing an example of the power distribution routine. When this power distribution routine is started, the CPU 72 of the electronic control unit 70 first supplies the system required power Psys * to the fuel cell stack 30 within a range not exceeding the battery maximum output power Pb and the FC maximum output power Pmax. Is distributed to the FC required power Pfc *, which is the required power, and the discharge required power Pb *, which is the required power to the battery (step S200). In the present embodiment, of the system required power Psys *, the travel required power Pdr * is basically output from the fuel cell stack 30, and the output power of the fuel cell stack 30 alone is insufficient during acceleration transients and high load operation. In such a case, the battery 58 is distributed so that power assist is performed. Subsequently, it is determined whether or not the acceleration transient flag F is 1 (step S202). Here, the acceleration transient flag F is a flag indicating that control during acceleration transient is being performed when the value is 1, and indicating that control during acceleration transient is not being performed when the value is zero. The control at the time of acceleration transition means that when a large travel demand power Pdr * is set, the travel demand power Pdr * cannot be immediately output from the fuel cell stack 30 due to a follow-up delay of the air compressor 22 or the like. This refers to assisting processing, and specifically refers to processing after step S216 described later.

  When the acceleration transient flag F is zero in step S202, it is determined whether the power generation operation of the fuel cell stack 30 is stopped (step S204). When the power generation operation is in progress, the fuel cell stack 30 is stopped. It is determined whether or not a condition (FC stop condition) is satisfied (step S206). In the present embodiment, the FC stop condition is that the system required power Psys * is equal to or less than the threshold value Pref, and the battery 58 can output the system required power Psys * alone (that is, the battery maximum output power Pbmax is equal to or higher than the system required power Psys *). ). If the FC stop condition is not satisfied in step S206, the power distribution routine is terminated as it is. That is, when the power generation operation of the fuel cell stack 30 is performed and the FC stop condition is not satisfied, not during the acceleration transition, the FC required power Pfc * and the discharge required power Pb * set in step S200 are employed.

  On the other hand, when the FC stop condition is satisfied in step S206, the threshold value Pref is set based on the battery maximum output power Pbmax (step S208). For the threshold value Pref, the relationship between the battery maximum output power Pbmax and the threshold value Pref is determined in advance and stored in the ROM 74 as a threshold setting map. When the battery maximum output power Pbmax is given, the corresponding threshold value Pref is derived from the stored map. And set it. FIG. 8 shows an example of the threshold setting map. That is, when the battery maximum output power Pbmax is in the range from zero to the reference value Pstd, the threshold value Pref is set to the value Pref0, and when it is in the range exceeding the reference value Pstd, the threshold value Pref is set to the value Pref1 (<Pref0). The threshold value Pref is set to the value Pref0 when the system is started. Further, the reference value Pstd is a value that is felt that acceleration by the power assist of the battery 58 is not sufficient, and is a value obtained empirically. After setting the threshold value Pref in this manner, the FC required power Pfc * is set to zero, the discharge required power Pb * is set to the system required power Psys * (step S210), and this power distribution routine is terminated. That is, when the FC stop condition is satisfied, the FC required power Pfc * is set to zero, and the discharge required power Pb * is set to the system required power Psys *.

  On the other hand, when the power generation operation of the fuel cell stack 30 is stopped in step S204, it is determined whether or not the restart condition (FC restart condition) of the fuel cell stack 30 is satisfied (step S212). In the present embodiment, the FC restart condition is that the system required power Psys * exceeds the threshold value Pref and the battery 58 cannot output the system required power Psys * alone (that is, the battery maximum output power Pbmax is less than the system required power Psys *). It is assumed that it will be established. If the FC restart condition is not satisfied in step S212, the processing of steps S208 and S210 is executed and the power distribution routine is terminated. That is, when the power generation operation of the fuel cell stack 30 is stopped, the FC required power Pfc * is set to zero, and the discharge required power Pb * is set to the system required power Psys *.

  On the other hand, when the FC restart condition is satisfied in step S212, it is determined whether or not the driver is requesting rapid acceleration (step S214). This determination is made, for example, based on whether or not the rate of change of the accelerator opening Acc with respect to time (for example, the difference ΔAcc obtained by subtracting the previous accelerator opening Acc from the current accelerator opening Acc) exceeds a predetermined change rate. The predetermined change rate at this time is empirically set as an upper limit value that allows the fuel cell stack 30 to output the FC required power Pfc * without much delay. If it is determined in step S214 that the acceleration is not abrupt, the power distribution routine is terminated as it is. That is, if the rapid acceleration is not required when restarting the fuel cell stack 30 in which the power generation operation is stopped, the FC required power Pfc * and the discharge required power Pb * set in step S200 are employed.

  On the other hand, when it is determined in step S214 that the driver is requesting rapid acceleration, a value 1 is set to the acceleration transient flag F (step S216), and rate processing for releasing the power assist of the battery 58 (step S216). It is determined whether or not step S228 described later is being executed (step S218). Considering immediately after it is determined that the acceleration is abrupt in step S214, since the rate process is not executed, a negative determination is made in step S218, and the FC required power Pfc * is the value set in step S200. The discharge required power Pb * is set to the battery maximum output power Pbmax (step S220). Since it takes time until the fuel cell stack 30 outputs the FC required power Pfc * due to a delay in the follow-up of the air compressor 22, the battery 58 can quickly output the discharge required power Pb *. The discharge request power Pb * is set to the battery maximum output power Pbmax to meet the driver's acceleration request. Thereafter, the current FC output power Pfc is calculated from the output current Ifc and output voltage Vfc of the fuel cell stack 30, and the difference obtained by subtracting the sum of the current FC output power Pfc and the battery maximum output power Pbmax from the system required power Psys *. ΔP is calculated (step S222), and it is determined whether or not the difference ΔP has become substantially zero, that is, whether or not the system required power Psys * is output from the fuel cell stack 30 and the battery 58 ( Step S224). Now, since the driver is thinking immediately after requesting rapid acceleration, a negative determination is made in step S224, and this power distribution routine ends. In the subsequent power distribution routine, since it is determined in step S202 after step S200 that the acceleration transient flag F is a value 1, the process proceeds to step S218. However, since rate processing has not yet been executed, a negative result is obtained in step S218. A determination is made, and after steps S220 and S222, a negative determination is made in step S224, and this routine is repeated. That is, the system required power Psys * at the time of sudden acceleration can be output from the fuel cell stack 30 and the battery 58 immediately after the sudden acceleration is requested when restarting the fuel cell stack 30 in the power generation operation stop. During this time, the value set in step S200 is adopted as the FC required power Pfc *, and the battery maximum output power Pbmax is adopted as the discharge required power Pb *.

  If the difference ΔP becomes substantially zero while such processing is repeated, a positive determination is made in step S224 to determine whether or not the current FC output power Pfc substantially matches the FC required power Pfc *. (Step S226). If the current FC output power Pfc does not coincide with the FC required power Pfc * in step S226, a rate process is performed to lower the required discharge power Pb * from the previous value at a predetermined rate (step S228). Exit. In the subsequent power distribution routine, since it is determined in step S202 after step S200 that the acceleration transient flag F is a value 1, the process proceeds to step S218. Since the rate is being processed, a positive determination is made, and step S226 is performed. In step S228, a negative determination is made because the current FC output power Pfc does not yet match the FC required power Pfc *. After the discharge required power Pb * is reduced at a predetermined rate in step S228, this routine is terminated. The process is repeated. That is, until the fuel cell stack 30 can output the FC required power Pfc * after the system required power Psys * at the time of rapid acceleration can be output by the fuel cell stack 30 and the battery 58, the FC The value set in step S200 is adopted as the required power Pfc *, and the rate-processed value is adopted as the required discharge power Pb *.

  If the current FC output power Pfc from the fuel cell stack 30 substantially coincides with the FC required power Pfc * while such processing is repeated, a positive determination is made in step S226, and the acceleration transient flag F is set to zero. (Step S230), and this routine is terminated. That is, after the processing during acceleration transition is completed, the FC required power Pfc * and the discharge required power Pb * set in step S200 are employed.

  Next, a specific example of the above-described processing during acceleration transition will be described with reference to FIG. FIG. 9 is an explanatory diagram of a specific example at the time of acceleration transient. (A) is a graph showing the transition of the system required power Psys * with respect to time, and (b) is the total output power of the fuel cell stack 30 and the battery 58 with respect to time. (C) is a graph showing the transition of the total output power of the fuel cell stack 30 and the battery 58 with respect to time (when the SOC is lowered).

  First, a normal case, that is, a case where the battery maximum output power Pbmax exceeds the reference value Pstd will be described with reference to FIG. 9B. In this case, the threshold value Pref is set to the value Pref0, and when the driver greatly depresses the accelerator pedal 83, the restart condition is satisfied at the time Ta when the system required power Psys * exceeds the value Pref0. Since it takes time until the power is output from the fuel cell stack 30 in the power generation operation stop, only the battery maximum output power Pbmax is output from the battery 58 at the time point Ta, and the delay time Tlag from the time point Ta is When the time has elapsed, power starts to be output from the fuel cell stack 30. Until the delay time Tlag elapses, the difference ΔPb obtained by subtracting the battery output power before the accelerator is depressed from the battery maximum output power Pbmax becomes a motor torque change and is used for acceleration of the vehicle. Further, after the delay time Tlag has elapsed, the sum of the difference ΔPb and the FC output power Pfc becomes a motor torque change and is used for acceleration of the vehicle. Thereafter, when the total output power of the fuel cell stack 30 and the battery 58 coincides with the system required power Psys * at the time Tc, the discharge required power Pb * is gradually rate-processed from the battery maximum output power Pbmax starting from the time Tc. The rate processing is terminated when the current FC output power Pfc of the fuel cell stack 30 coincides with the FC required output power Pfc *.

  Next, the case where the battery SOC is lowered, that is, the case where the battery maximum output power Pbmax is equal to or less than the reference value Pstd will be described with reference to FIG. In this case, the threshold value Pref is set to the value Pref1, and when the driver greatly depresses the accelerator pedal 83, the restart condition is satisfied at the time Tb (<Ta) when the system required power Psys * exceeds the value Pref1. Since it takes time until the power is output from the fuel cell stack 30 during the power generation operation stop, only the battery maximum output power Pbmax is output from the battery 58 at the time Tb, and the delay time Tlag from the time Ta is When the time has elapsed, power starts to be output from the fuel cell stack 30. Until the delay time Tlag elapses, the difference ΔPb obtained by subtracting the battery output power before the accelerator is depressed from the battery maximum output power Pbmax becomes a motor torque change and is used for acceleration of the vehicle. Further, after the delay time Tlag has elapsed, the sum of the difference ΔPb and the FC output power Pfc becomes a motor torque change and is used for acceleration of the vehicle. Here, the battery maximum output power Pbmax is lower than the normal time, but the time Tb when the restart condition is satisfied is earlier than the normal time, so the time when the power starts to be output from the fuel cell stack 30 is also earlier than the normal time. Become. As a result, the point in time when the total output power of the fuel cell stack 30 and the battery 58 coincides with the system required power Psys * is substantially the same as in normal times, and the drivability during acceleration is normal and when the battery SOC is low. There is no big difference. Then, starting from this point, the required discharge power Pb * is gradually reduced from the battery maximum output power Pbmax by rate processing, and when the current FC output power Pfc of the fuel cell stack 30 matches the FC required output power Pfc *. End rate processing.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be described. The battery 58 of this embodiment corresponds to the power storage means of the present invention, and the electronic control unit 70 corresponds to the electric energy supply control means, the stop / restart control means, and the threshold value changing means. The present embodiment also clarifies an example of a control method of the fuel cell vehicle 10 by explaining the operation of the fuel cell vehicle 10.

  As described above in detail, according to the fuel cell vehicle 10 of the present embodiment, the power generation operation of the fuel cell stack 30 is stopped when a predetermined stop condition is satisfied, and the system request is made while the power generation operation of the fuel cell stack 30 is stopped. When the restart condition including that the power Psys * exceeds the threshold value Pref is satisfied, the power generation operation of the fuel cell stack 30 is restarted, but the threshold value Pref is changed based on the magnitude of the battery maximum output power Pbmax. Therefore, it is possible to suppress a decrease in vehicle power performance after restarting the fuel cell stack 30 in which the power generation operation is stopped. That is, when the battery maximum output power Pbmax is lower than the reference value Pstd, the power assist of the battery 58 is weakened. However, since the threshold value Pref is changed from the normal value Pref0 to a lower value Pref1, the fuel during power generation operation stop The battery stack 30 restarts earlier than normal, and power is supplied from the fuel cell stack 30 to the motor and the like earlier than normal. For this reason, it can suppress that the vehicle motive power performance (especially feeling of acceleration) after restarting the fuel cell stack 30 in the power generation operation stop is reduced.

  By the way, in the case of the fuel cell vehicle 10 of the present embodiment, electric energy is supplied and consumed not only to the motor 52 that drives the vehicle but also to the air compressor 22 and the hydrogen circulation pump 20 as auxiliary devices of the fuel cell stack 30. . Further, if the electric energy is converted into voltage, it is also supplied to and consumed by an electric steering, an electric brake, an air conditioner, etc. (not shown). That is, the motor 52, the air compressor 22, the hydrogen circulation pump, and the like correspond to the electric energy consuming apparatus of the present invention. The fuel cell stack 30 and the battery 58 cover the total electric energy required by each consuming device, and the acceleration performance (drivability) of the vehicle may deteriorate depending on the status of the required electric energy of each consuming device. However, in this embodiment, the deterioration can be suppressed by adopting the power distribution routine described above.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the embodiment described above, the threshold value Pref is changed stepwise (step function) with respect to the battery maximum output power Pbmax, but may be changed continuously as shown in FIG. Good. At this time, it may be changed substantially linearly as shown in FIG. 10, but may be changed to an n-order curve (n is an integer of 2 or more).

  In the above-described embodiment, the battery maximum output power Pbmax, which is the upper limit power that can be output from the battery 58, is set as the electric energy that can be discharged from the battery 58. However, a predetermined power (for example, necessary in an emergency) from the battery maximum output power Pbmax. The value obtained by subtracting the power) may be the electric energy that can be discharged from the battery 58.

  Furthermore, in the above-described embodiment, one of the FC restart conditions is that the system required power Psys * exceeds the threshold value Pref. However, when the system required power Psys * exceeds the threshold value Pref, the travel required power Pdr * increases rapidly. Therefore, the travel request power Pdr * when the system request power Psys * matches the threshold value Pref is determined as the threshold value Pdrref, and instead of the system request power Psys * exceeding the threshold value Pref, the travel request power Pdr * is set to the threshold value Pdrref. One of the restart conditions may be exceeded.

  Furthermore, in the above-described embodiment, control is performed to limit the power that can pass through the DC / DC converter 56 based on the temperature of the DC / DC converter 56 as compared with the normal time, and based on this limited power. The threshold value Pref may be changed. Specifically, in step S100 of the drive control routine of FIG. 4, the electronic control unit 70 inputs the temperature of the boost IPM 56a and the temperature of the reactor 56c from the IPM temperature sensor 56b and the reactor temperature sensor 56d of the DC / DC converter 56, respectively. When the battery maximum output power Pbmax is calculated in step S130, the maximum allowable power Pbmax is set to the reference value Pstd when either the temperature of the boost IPM 56a or the temperature of the reactor 56c exceeds a predetermined overheat determination reference temperature. Limit to below. Here, the overheat determination reference temperature is a temperature at which it is difficult to guarantee the operation of the step-up IPM 56a and the reactor 56c unless the power passing through the DC / DC converter 56 is limited, and is set empirically. . In this way, when the DC / DC converter 56 is in an overheated state and the battery maximum output power Pbmax is limited, the power assist of the battery 58 is weakened. However, in step S208 of the power distribution routine of FIG. Since it is set to <Pref0), the total output power changes in the same manner as in FIG. Therefore, it is possible to suppress a decrease in the power performance (particularly acceleration feeling) of the vehicle after restarting the fuel cell stack 30 in which the power generation operation is stopped.

  In the above-described embodiment, the threshold value Pref is set based on the battery maximum output power Pbmax in step S208 of the power distribution routine of FIG. 7, but instead, the following (1), (2) The threshold value Pref may be set as described above.

(1) The threshold value Pref may be set based on the IV characteristics of the fuel cell stack 30. Specifically, the output current Ifc and output voltage Vfc of the fuel cell stack 30 during the power generation operation in step S100 of the drive control routine of FIG. 3 are stored for a certain period, and the steps of the power distribution routine of FIG. When the FC stop condition is satisfied in S206, the FC stop condition is satisfied from the output current Ifc and the output voltage Vfc stored for a certain period instead of changing the threshold value Pref based on the battery maximum output power Pbmax in the subsequent step S208. The IV characteristic of the immediately preceding fuel cell stack 30 is obtained, and the threshold value Pref is set based on the IV characteristic. Here, the threshold value Pref is stored in the ROM 74 as a threshold setting table by predetermining the relationship between the IV characteristic and the threshold value Pref. When the IV characteristic is given, the corresponding threshold value Pref is obtained from the stored map. Derived and set. Table 1 below shows an example of the threshold setting table. In Table 1, the allowable range refers to a range from the initial characteristic (characteristic at the time of factory shipment) to the reference characteristic IVstd which is an allowable limit, and FIG. 11 shows the relationship between the reference characteristic IVstd and the allowable range. According to the table in Table 1, the threshold value Pref is set to the value Pref0 when the IV characteristic is in the range from the initial characteristic (characteristic at the time of factory shipment) to the reference characteristic IVstd that is the allowable limit, that is, within the allowable range. The threshold value Pref is set to the value Pref1 (<Pref0) when it is in the range exceeding the reference characteristic IVstd, that is, outside the allowable range.

  A specific example of the processing during acceleration transition at this time will be described with reference to FIG. FIG. 12 is an explanatory diagram of a specific example at the time of acceleration transient, where (a) is a graph showing the transition of the system required power Psys * with respect to time, and (b) is the total output power of the fuel cell stack 30 and the battery 58 with respect to time. (C) is a graph showing the transition of the total output power of the fuel cell stack 30 and the battery 58 with respect to time (when the IV characteristic is deteriorated). In addition, since it is the same as that of embodiment mentioned above about the normal time, the description is abbreviate | omitted. When the IV characteristic is deteriorated, the threshold value Pref is set to the value Pref1, and when the driver greatly depresses the accelerator pedal 83, the threshold value Pref is restarted at the time Tb (<Ta) when the system required power Psys * exceeds the value Pref1. The start condition is met. Since it takes time until the power is output from the fuel cell stack 30 during the power generation operation stop, at the time Tb, the battery 58 only outputs the battery maximum output power Pbmax (here, the same magnitude as in normal time). The power starts to be output from the fuel cell stack 30 when the delay time Tlag has elapsed from this point Ta. Until the delay time Tlag elapses, the difference ΔPb obtained by subtracting the battery output power before the accelerator is depressed from the battery maximum output power Pbmax becomes a motor torque change and is used for acceleration of the vehicle. Further, after the delay time Tlag has elapsed, the sum of the difference ΔPb and the FC output power Pfc becomes a motor torque change and is used for acceleration of the vehicle. Here, since the IV characteristic is deteriorated compared with the normal time, the rate of increase of the current FC output power Pfc with respect to the time is small, but the time Tb when the restart condition is satisfied is earlier than the normal time. The time at which power starts to be output from 30 is also earlier than the normal time. As a result, the time when the total output power of the fuel cell stack 30 and the battery 58 coincides with the system required power Psys * is substantially the same as the normal time, and the drivability during acceleration is normal and when the IV characteristics are deteriorated. There will be no big difference. Therefore, similarly to the above-described embodiment, it is possible to suppress a decrease in the power performance (particularly acceleration feeling) of the vehicle after restarting the fuel cell stack 30 in which the power generation operation is stopped.

  (2) An external air pressure sensor capable of measuring the external air pressure is installed near the air intake port of the air compressor 22, and the electronic control unit 70 inputs the external air pressure from the external air pressure sensor and changes the threshold value Pref based on the external air pressure. You may make it do. Specifically, the electronic control unit 70 inputs the external air pressure from the external air pressure sensor in step S100 of the drive control routine of FIG. 3, and the threshold value Pref is set based on the battery maximum output power Pbmax in step S208 of FIG. Instead of changing, the threshold value Pref is changed to a value Pref1 lower than the normal value Pref0 when the external air pressure is lower than normal. Here, when the external air pressure is low and high, even if the suction operation of the air compressor 22 is the same, the substantial air intake amount is smaller when the external air pressure is low than when it is high. By changing the threshold value Pref based on the outside air pressure, the time when the fuel cell stack 30 in the power generation operation stop is restarted (that is, the time when electric energy starts to be supplied from the fuel cell stack 30 to the motor 52, etc.) is changed. There is a meaning. In this way, when the external air pressure is low, such as at high altitudes, the rate of increase of the current FC output power Pfc with respect to time becomes small, but the threshold value Pref is set to the value Pref1 (<Pref0) in step S208 of the power distribution routine of FIG. Therefore, the total output power changes in the same manner as in FIG. Therefore, it is possible to suppress a decrease in the power performance (particularly acceleration feeling) of the vehicle after restarting the fuel cell stack 30 in which the power generation operation is stopped.

It is a block diagram which shows the outline of a structure of a fuel cell vehicle. It is a block diagram which shows the outline of a structure of a fuel cell. It is a circuit diagram which shows the outline of a DC / DC converter. It is a flowchart of a drive control routine. It is explanatory drawing which shows an example of the driving | running | working request torque setting map. It is explanatory drawing which shows the characteristic of a fuel cell stack. It is a flowchart of a power distribution routine. It is explanatory drawing which shows an example of the map for threshold value setting. It is explanatory drawing which shows the specific example at the time of acceleration transition. It is explanatory drawing which shows an example of the map for threshold value setting. It is explanatory drawing which shows the relationship between standard characteristic IVstd and tolerance | permissible_range. It is explanatory drawing which shows the specific example at the time of acceleration transition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell system, 12 Hydrogen cylinder, 14 Regulator, 18 Anode purge valve, 20 Hydrogen circulation pump, 22 Air compressor, 24 Humidifier, 26 Air pressure regulation valve, 30 Fuel cell stack, 31 Ammeter, 32 Fuel gas discharge pipe, 33 Voltmeter, 34 Oxidizing gas discharge pipe, 40 Fuel cell, 42 Solid electrolyte membrane, 43 Anode, 44 Cathode, 45 Separator, 46 Fuel gas channel, 47 Oxidizing gas channel, 52 Motor, 53 Power line, 54 Inverter, 56 DC / DC converter, 56a step-up IPM, 56b IPM temperature sensor, 56c reactor, 56d reactor temperature sensor, 58 battery, 62 differential gear, 63 drive wheel, 64 drive shaft, 70 electronic control unit, 72 CPU, 74 ROM, 76 RAM, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor.

Claims (6)

An electric energy consuming device mounted on a vehicle;
A fuel cell capable of supplying electric energy generated by an electrochemical reaction between a fuel gas and an oxidizing gas to the electric energy consuming device;
Power storage means capable of discharging charged electric energy and supplying the electric energy consuming device;
Electric energy supply control means for supplying electric energy of one or both of the fuel cell and the power storage means to the electric energy consuming device based on a vehicle state;
A predetermined restart condition including stopping the power generation operation of the fuel cell when a predetermined stop condition is satisfied, and the electric energy required for the vehicle during the stop of the power generation operation of the fuel cell exceeding a predetermined threshold A stop / restart control means for restarting the power generation operation of the fuel cell when
Threshold value changing means for changing the threshold value to a value lower than normal when the current-voltage characteristics of the fuel cell are degraded from normal ; and
Fuel cell vehicle equipped with. An electric energy consuming device mounted on a vehicle;
A fuel cell capable of supplying electric energy generated by an electrochemical reaction between a fuel gas and an oxidizing gas to the electric energy consuming device;
Oxidizing gas supply means for sucking outside air and supplying the outside air as the oxidizing gas to the fuel cell;
Power storage means capable of discharging charged electric energy and supplying the electric energy consuming device;
Electric energy supply control means for supplying electric energy of one or both of the fuel cell and the power storage means to the electric energy consuming device based on a vehicle state;
A predetermined restart condition including stopping the power generation operation of the fuel cell when a predetermined stop condition is satisfied, and the electric energy required for the vehicle during the stop of the power generation operation of the fuel cell exceeding a predetermined threshold A stop / restart control means for restarting the power generation operation of the fuel cell when
Threshold changing means for changing the threshold to a value lower than normal when the pressure of the outside air is lower than normal ;
Fuel cell vehicle equipped with. The threshold value changing means, the dischargeable electric energy storage means is when lower than the normal changes the threshold to the normal value lower than when the fuel cell vehicle according to claim 1 or 2. The fuel cell vehicle according to any one of claims 1 to 3 ,
Voltage adjusting means for adjusting an operating point of the fuel cell interposed between the power storage means and the electric energy consuming device;
Passing energy setting means for setting the electrical energy that can pass through the voltage adjusting means based on the state of the voltage adjusting means;
With
The threshold value changing means changes the threshold value to a value lower than normal time when the electric energy set by the passing energy setting means is restricted from normal time.
Fuel cell vehicle. An electric energy consuming device mounted on a vehicle; a fuel cell capable of supplying electric energy generated by an electrochemical reaction between a fuel gas and an oxidizing gas to the electric energy consuming device; and discharging charged electric energy to A method for controlling a fuel cell vehicle comprising a power storage means capable of being supplied to an electric energy consuming device,
At the time of traveling, the electric energy of either one or both of the fuel cell and the power storage means is supplied to the electric energy consuming device based on the traveling state, and the power generation operation of the fuel cell is performed when a predetermined fuel cell stop condition is satisfied. Stops and restarts the power generation operation of the fuel cell when a predetermined fuel cell restart condition is satisfied, including that the electric energy required for the vehicle exceeds a predetermined threshold while the fuel cell power generation operation is stopped And, when the current-voltage characteristics of the fuel cell are deteriorated than normal, the threshold value is changed to a value lower than normal before the restart.
Control method for fuel cell vehicle. An electric energy consuming device mounted on a vehicle, a fuel cell capable of supplying electric energy generated by an electrochemical reaction between fuel gas and oxidizing gas to the electric energy consuming device, and sucking outside air into the oxidizing gas As a control method for a fuel cell vehicle, comprising: an oxidizing gas supply means for supplying to the fuel cell; and a power storage means capable of discharging charged electric energy and supplying it to the electric energy consuming device,
At the time of traveling, the electric energy of either one or both of the fuel cell and the power storage means is supplied to the electric energy consuming device based on the traveling state, and the power generation operation of the fuel cell is performed when a predetermined fuel cell stop condition is satisfied. Stops and restarts the power generation operation of the fuel cell when a predetermined fuel cell restart condition is satisfied, including that the electric energy required for the vehicle exceeds a predetermined threshold while the fuel cell power generation operation is stopped When the outside air pressure is lower than normal, the threshold is changed to a value lower than normal before the restart.
Control method for fuel cell vehicle.

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