JP2010003509A - Fuel cell vehicle and its control method in highlands - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell vehicle inhibiting decrease of output of a fuel cell when running in highlands and capable of supplying power necessary for driving to the fuel cell. <P>SOLUTION: The fuel cell vehicle 1 provided with a fuel cell 5 generating power by receiving a supply of anode gas and cathode gas is equipped with an external atmospheric pressure obtaining means 4 for obtaining an external atmospheric pressure outside the fuel cell vehicle, a gas-liquid separation unit 7 for separating water from anode offgas exhausted from the fuel cell 5 and storing the same, a drain valve 8 for exhausting the water stored in the gas-liquid separation unit 7, a bypass passage 19 for returning the anode offgas after separating water to an anode supplying passage for supplying the anode gas to the fuel cell 5, and a control part 3 for controlling exhausting of the water exhausted from the drain valve 8. The control part 3 performs exhaust control so that an exhausting amount of the water exhausted from the drain valve 8 may be decreased as the external atmospheric pressure decreases. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell vehicle including a fuel cell that is supplied with an anode gas and a cathode gas to generate electric power, and a control method for the fuel cell vehicle.

When traveling on high altitude with a fuel cell vehicle, the output from the fuel cell may be lower than when traveling on flat ground, and the output required for traveling may not be obtained. Air (strictly speaking, oxygen contained in air) is used as the cathode gas of the fuel cell provided in the fuel cell vehicle. Air is taken in from the outside air of the fuel cell vehicle by an air compressor and pumped to the fuel cell. When the fuel cell vehicle travels on high altitudes, the outside air is thin, so the load of the air compressor that tries to supply the same amount of air as on the flat ground becomes large, and the power for the travel becomes insufficient. By the way, in traveling on flat ground, an excess amount of air exceeding the amount necessary for power generation is supplied to the fuel cell by the air compressor for the purpose of discharging generated water. Therefore, in highland travel, a method has been proposed in which the amount of excess air exceeding the amount necessary for power generation is reduced to reduce the amount of air supply (see, for example, Patent Document 1).
JP 2008-91257 A

  However, in the conventional method, the cathode side of the fuel cell is dried, and the output of the fuel cell may be reduced.

  In view of the above, the present invention provides a fuel cell vehicle capable of suppressing a decrease in the output of a fuel cell and allowing the fuel cell to supply power necessary for traveling when traveling on a high altitude, and a control method for the high altitude. The purpose is to do.

A first aspect of the present invention is a fuel cell vehicle including a fuel cell that is supplied with anode gas and cathode gas (air) to generate power,
External pressure acquisition means for acquiring the external air pressure of the outside air of the fuel cell vehicle, a gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell, and is stored in the gas-liquid separator A drain valve for discharging the moisture, a bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell, and discharge control of the moisture discharged from the drain valve A control unit,
The said control part performs discharge | emission control which reduces the discharge | emission amount of the said water | moisture content discharged | emitted from the said drain valve, so that the said external pressure falls.

  First, why the cathode side of the fuel cell was dry in the highland will be explained.

  The pressure on the suction side of the air compressor decreases as the altitude increases. On the other hand, the pressure on the discharge side of the air compressor is increased to a pressure that is substantially the same as that on flat ground even at high altitudes. For this reason, the compression ratio represented by (pressure on the discharge side) / (pressure on the suction side) is higher in the highlands than in the flat ground. For this reason, the temperature rise by adiabatic compression becomes larger in the highlands than the flat ground, and the temperature of the air discharged from the air compressor is higher in the highlands than the flat ground.

  In order to cool the air (cathode gas) discharged from the air compressor, an intercooler may be provided after the air compressor. However, the cooling capacity of the intercooler decreases at higher altitudes. It becomes difficult to lower the temperature of the compressed air. In particular, when the intercooler is air-cooled, the cooling capacity at high altitudes is much lower than that of the water-cooled intercooler. For this reason, the temperature of the air discharged from the intercooler does not change higher in the highlands than in the flatlands, the temperature of the air in the highlands stays high, and the temperature difference from the temperature of the air in the flatlands becomes even larger. .

  A humidifier may be provided after the intercooler. Since moisture is generated as a by-product of a chemical reaction accompanied by power generation at the cathode of the fuel cell, the humidifier humidifies the air using the cathode off-gas containing this moisture. The temperature of the air coming into the humidifier from the air compressor is higher in the highlands than on the flat ground, but the higher the temperature, the higher the saturated water vapor amount and the relative humidity (= humidity amount / saturated water vapor amount). ) Will go down. An increase in the amount of saturated water vapor is considered to be an improvement in the ability to take water away from others. And humidification can be said to reduce the ability to deprive this moisture. Here, if the humidifier is humidified to the same level as the flat ground, the ability to deprive this moisture in the higher ground is higher than the flat ground. In the case of high altitudes, the cathode off-gas is returned to the humidifier while being more capable of depriving moisture than the flat ground, so the cathode off-gas has a high capability of depriving moisture (in other words, the ability to release moisture is low). Inability to move moisture to the air (cannot humidify), the ability to take away moisture from the air at high altitudes remains high, and the difference from the ability to take away moisture from the air on flat ground becomes even greater End up.

  The fuel cell cathode is placed after the humidifier, and in high altitudes, air that has a high capacity to take moisture away from the flat ground (air with insufficient humidification) is supplied to the cathode from the cathode side of the fuel cell. , Dehydrated and dry. This is the reason why the cathode side of the fuel cell dries at high altitude. For whatever reason, the temperature of the air toward the humidifier becomes high at high altitude. Moreover, whatever the reason, the air after leaving the humidifier becomes damp underhumidity at high altitude.

  Next, when the control unit performs discharge control to reduce the amount of water discharged from the drain valve as the outside air pressure decreases, that is, as the altitude rises, the fuel cell cathode side is dried. I will explain how we can prevent this.

  Moisture generated as a by-product of a chemical reaction involving power generation is generated at the cathode and stays in the cathode gas flow channel, diffuses from the cathode to the anode (diffuse), and stays in the anode gas flow channel. To do. And when the cathode side of the fuel cell dries at high altitude, the moisture concentration gradient reverses and the moisture concentration becomes lower on the cathode side than on the anode side, so that the moisture diffused to the anode is back-diffused (back diffusion) It can be returned to the cathode, and drying on the cathode side can be prevented. If the discharge control is performed to reduce the amount of moisture discharged from the drain valve, the amount of moisture remaining on the anode side becomes larger, and more moisture can be returned to the cathode by back diffusion. Can be prevented from drying. Whatever the reason, the amount of moisture diffusing from the cathode to the anode is reduced.

  In summary, the higher the altitude, the lower the external air pressure, the lower the external air pressure, the higher the air temperature, the higher the air temperature, the more dry the cathode side, and the more dry the cathode side, the greater the amount of moisture that will diffuse back. The amount of water discharged from the drain valve is decreased as the amount of water to be back-diffused is increased.

The second aspect of the present invention is a fuel cell vehicle including a fuel cell that generates power by being supplied with an anode gas and a cathode gas (air),
An outside air pressure obtaining means for obtaining an outside air pressure of the outside air of the fuel cell vehicle, a gas-liquid separator that separates moisture from the anode off gas discharged from the fuel cell, and the anode off gas after the moisture separation A bypass path for returning to the anode supply path for supplying the anode gas to the battery, a purge valve for discharging the anode off-gas after the moisture separation, and a controller for controlling the discharge of the anode off-gas discharged from the purge valve. Prepared,
The control unit performs discharge control for reducing the discharge amount of the anode off-gas discharged from the purge valve as the external pressure decreases.

  In the first invention described above, moisture liquefied by gas-liquid separation is discharged from the drain valve to the outside. In the second aspect of the invention, vaporized water and the like are discharged from the purge valve together with the anode off gas. If the discharge amount of the anode off-gas is decreased, the amount of water remaining on the anode side can be increased, so that the amount of water that is back-diffused increases and drying on the cathode side can be prevented. Moreover, if the discharge amount of the anode off gas is reduced, the supply amount of the dried anode gas supplied from the high-pressure hydrogen tank can be reduced. This also allows the anode side to be kept moist and increases the amount of water to be back-diffused, thereby preventing the cathode side from being dried.

  In the first aspect of the present invention, a purge valve for discharging the anode off-gas after the moisture separation is provided, and the control unit discharges from the purge valve as the external pressure decreases in the discharge control. It is preferable to reduce the discharge amount of the anode off gas. Both the drain valve and the purge valve can reduce the amount of water to be discharged more, increase the amount of water to be back-diffused (reduce the amount of water to be diffused), and prevent drying on the cathode side.

  In the first and second aspects of the present invention, the control unit determines whether or not the cathode gas supplied to the fuel cell is in a dry state, and the cathode gas is in a dry state. It is preferable to perform the discharge control when it is determined. Thereby, the dry state on the cathode side can be specified, and the discharge control can be performed when the cathode side is dry.

  In the first and second aspects of the present invention, the fuel cell vehicle includes a power generation state measuring device that measures a power generation state of the fuel cell, and the control unit is based on the measured power generation state. It is preferable to determine whether or not the cathode gas supplied to the fuel cell is in a dry state. Since the power generation state measuring device can be easily installed in the fuel cell, the dry state determination result can be easily obtained.

  In the first and second aspects of the present invention, the fuel cell vehicle includes a hygrometer for measuring the humidity of the cathode gas supplied to the fuel cell, and the control unit is configured to measure the humidity. Based on the above, it is preferable to determine whether or not the cathode gas supplied to the fuel cell is in a dry state. According to the hygrometer, the dry state can be directly specified, and an accurate determination result of the dry state can be acquired.

  In the first and second aspects of the present invention, the control unit determines whether or not to reduce the supply amount of the cathode gas (air) supplied to the fuel cell, and the cathode gas When it is determined that the cathode gas supply amount is reduced and it is determined that the cathode gas supply amount is reduced, it is preferable to perform control to reduce the cathode gas supply amount as the external pressure decreases.

  By reducing the amount of air supplied, the power consumption of the air compressor can be reduced, as well as the amount of moisture taken away from the cathode side by air (insufficient humidification) can be reduced, preventing drying of the cathode side. be able to. Note that reducing the amount of air supplied is considered to reduce the amount of power generated by the fuel cell. However, the amount of air supplied includes an excess supply amount that is a surplus in addition to the essential supply amount essential for power generation. The amount of excess supply is reduced, and by reducing this excess supply amount, if the air supply amount is reduced, the required supply amount has not been reduced. Absent. The purpose of adding the excess supply amount is to push out the moisture generated and retained at the cathode on the flat ground to the discharge side. The supply amount can be reduced.

  In the first and second aspects of the present invention, the fuel cell vehicle includes a load state measuring device that measures a load state of the fuel cell, and the control unit determines that the measured load state is a load state threshold value. When it is smaller, it is preferable to determine that the supply amount of the cathode gas (air) is reduced. The excess supply amount varies depending on the load state of the fuel cell. The smaller the load, the larger the excess supply rate, and the larger the load, the smaller the excess supply rate. In other words, so-called stoichiometry, stoichiometry is expressed by (excess supply amount + essential supply amount) / (essential supply amount). The stoichiometry increases as the load decreases and decreases as the load increases. . This is because when the load increases, the amount of essential supply necessary for power generation also increases, so that moisture can be pushed out to the discharge side with the amount of essential supply necessary for power generation.

  In the first and second aspects of the invention, the fuel cell vehicle includes a diluter that dilutes and discharges the anode off gas with the cathode off gas discharged from the fuel cell, and the control unit includes the anode off gas. It is preferable to determine whether or not the supply amount of the cathode gas is reduced when it is determined whether or not the off-gas is discharged and it is determined that the anode off-gas is not discharged. A decrease in dilution rate can be suppressed.

Further, the third aspect of the present invention is a fuel cell that generates power by being supplied with an anode gas and a cathode gas;
An outside air pressure acquisition means for acquiring the outside air pressure of the fuel cell vehicle;
A gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell;
A drain valve for discharging the water stored in the gas-liquid separator;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A control unit for controlling the discharge of the water discharged from the drain valve, in a high altitude of a fuel cell vehicle,
The said control part performs discharge | emission control which reduces the discharge | emission amount of the said water | moisture content discharged | emitted from the said drain valve, so that the said external pressure falls. According to the third aspect of the present invention, the same effect as that of the first aspect of the present invention can be obtained.

Further, the fourth aspect of the present invention is a fuel cell that generates electricity by being supplied with an anode gas and a cathode gas;
An outside air pressure acquisition means for acquiring the outside air pressure of the fuel cell vehicle;
A gas-liquid separator that separates moisture from the anode off-gas discharged from the fuel cell;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A purge valve for discharging the anode off-gas after the moisture separation;
A control unit for controlling the discharge of the anode off-gas discharged from the purge valve at a high altitude of a fuel cell vehicle,
The control unit performs discharge control for reducing the discharge amount of the anode off-gas discharged from the purge valve as the external pressure decreases. According to the fourth aspect of the present invention, the same effect as that of the second aspect of the present invention can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, when drive | working a high altitude, the fuel cell vehicle which can suppress the fall of the output of a fuel cell and can supply electric power required for driving | running | working to a fuel cell, and the control method in the high altitude can be provided.

  Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a configuration diagram of a fuel cell vehicle 1 according to an embodiment of the present invention. The fuel cell vehicle 1 includes a fuel cell system 2, and the fuel cell system 2 includes a fuel cell (stack) 5 that is supplied with an anode gas and a cathode gas and generates electric power. In the fuel cell 5, when power is generated, the anode gas and the cathode gas undergo an electrochemical reaction to generate water. Moisture is generated at the cathode, stays in the gas flow path of the cathode gas, diffuses (diffuses) from the cathode to the anode, and stays in the gas flow path of the anode gas.

As the anode gas, for example, hydrogen (H ₂ ) can be used. The anode gas is supplied to the anode gas path of the fuel cell 5 and further to the anode via the ejector 6. Unreacted anode gas at the anode, moisture generated and retained, and the like are discharged from the gas path of the anode gas of the fuel cell 5 as anode off-gas. In the gas-liquid separator (catch tank) 7, a part of the moisture of the anode off gas is separated from the gas component such as the anode gas as a liquid component. The separated water is stored in the gas-liquid separator 7. The stored water is discharged outside the fuel cell system 2 via the diluter 10 when the drain valve 8 is opened.

  The anode off gas after the moisture separation is sucked into the ejector 6 by the negative pressure generated in the ejector 6, and is returned to the anode supply path for supplying the anode gas to the fuel cell 5 via the bypass path 19. By so-called anode circulation, unreacted anode gas is reacted and reduced to increase the reaction efficiency of the anode gas.

  A part of the water is contained in the anode off-gas after the water separation as a gas component. Since the uncirculated anode gas is dry and tends to take moisture away from the anode and dry it, the moisture contained in the anode off-gas will return to the anode, keeping the anode moist and preventing drying. it can. Further, if the anode off gas is discharged without being circulated, dried uncirculated anode gas is supplied from a high-pressure hydrogen tank or the like as a substitute for the discharged amount, and moisture is deprived from the anode and the remaining moisture is reduced. When the anode off-gas is circulated, neither of these occur, so the anode can be kept moist and dryness can be prevented. That is, since it is dry at high altitudes, purging and draining can be reduced, which reduces the discharge of the anode gas to the outside and further prevents drying, which is convenient from the viewpoint of fuel consumption.

  As the cathode gas, for example, air (Air), strictly speaking, oxygen contained in air can be used. Air (cathode gas) is taken in from the atmosphere outside the fuel cell system 2, is pumped by the air compressor 11, passes through the intercooler 12 and the humidifier 14, and the gas path of the cathode gas of the fuel cell 5 and further the cathode. To be supplied. The intercooler 12 cools the cathode gas heated by the adiabatic compression by the air compressor 11.

  Unreacted cathode gas and remaining moisture at the cathode are discharged from the cathode gas gas path of the fuel cell 5 as cathode off-gas. The cathode off gas is sent to the humidifier 14. The humidifier 14 humidifies the cathode gas supplied to the fuel cell 5 with moisture contained in the cathode off gas. Since the unhumidified cathode gas has a tendency to take moisture away from the cathode and dry it, the cathode gas is humidified to prevent drying of the cathode. However, even if it humidifies with the humidifier 14, it is humid in highland. The back pressure valve 15 stably increases the pressure in the gas path of the cathode gas of the fuel cell 5. The cathode off gas is discharged to the outside of the fuel cell system 2 via the humidifier 14, the back pressure valve 15, and the diluter 10. The diluter 10 dilutes the anode off gas flowing in from the purge valve 9 and the drain valve 8 with the cathode off gas and discharges it to the outside. Further, a hygrometer 13 is provided in the subsequent stage of the humidifier 14 and in the previous stage of the fuel cell 5 in order to measure the humidity of the cathode gas. This hygrometer 13 is provided to measure the dry state on the cathode side. Therefore, if the dry state on the cathode side can be specified, it is arranged as shown in FIG. The dry state on the cathode side may be specified, or a hygrometer may be arranged at the rear stage of the fuel cell 5 to measure the humidity of the cathode off gas, and the dry state on the cathode side may be specified from the humidity of the cathode off gas.

  In addition, the fuel cell system 2 is provided with a power generation state measuring device 5 a that measures the power generation state of the fuel cell 5. The power generation state measuring device 5a includes a thermometer 16 that measures the temperature of the fuel cell 5, a voltmeter 17 that measures the output voltage of the fuel cell 5, and an ammeter 18 that measures the output current of the fuel cell 5. . In addition, the fuel cell system 2 is provided with a load state measuring device 5 b that measures the load state of the fuel cell 5. The load state measuring device 5b may also serve as the power generation state measuring device 5a. That is, the power generation state measuring device 5a or the control unit 3 may acquire output power and output current indicating the load state from the output voltage and output current indicating the power generation state.

  The fuel cell system 2 is provided with an ECU (electronic control unit: control unit) 3. Although details will be described later, the control unit 3 controls the discharge of moisture discharged from the drain valve 8 and the purge valve 9. Further, the fuel cell system 2 is provided with an external air pressure acquisition unit 4 that acquires the external air pressure of the outside air of the fuel cell vehicle 1. The external air pressure acquisition means 4 is intended to acquire the pressure of the air sucked into the air compressor 11. For this reason, the air pressure (external air pressure) may be directly measured using a barometer as the external air pressure acquisition means 4. Further, using GPS navigation, the altitude may be obtained from the obtained position information based on the map database, and the atmospheric pressure may be calculated from the altitude. Moreover, you may calculate an external atmospheric pressure from the acquired altitude using an altitude measurement means.

  FIG. 2 shows a flowchart of a control method at a high altitude of the fuel cell vehicle 1 according to the embodiment of the present invention.

  First, in step S1, the control unit 3 determines whether or not the ignition switch (IG) is turned off. If the ignition switch is turned off (step S1, Yes), the control method in the high altitude of the fuel cell vehicle 1 is stopped. If the ignition switch is not turned off (step S1, No), the process proceeds to step S2.

  Next, in step S2, the external air pressure acquisition unit 4 acquires the external air pressure.

  In step S3, the control unit 3 determines whether or not the current position is a high altitude based on the acquired external atmospheric pressure. Specifically, if the outside air pressure is equal to or lower than a pressure threshold such as 90 kPa, for example, it is determined to be highland, and if the outside air pressure exceeds the pressure threshold, it is determined not to be highland. If it is a highland (step S3, Yes), it will progress to step S4, and if it is not a highland (step S3, No), it will progress to step S16, and the control part 3 will perform normal operation like a flat ground, and will return to step S1 after that.

  In step S4, the hygrometer 13 measures the humidity of the cathode gas. Alternatively, the power generation state measuring device 5a measures the power generation state. Specifically, the temperature of the fuel cell 5 is measured with the thermometer 16, the output voltage to the load is measured with the voltmeter 17, and the output current to the load is measured with the ammeter 18.

  In step S5, the control unit 3 determines whether or not the cathode side of the fuel cell 5 is in a dry state. If it is a dry state (step S5, Yes), it will progress to step S6, and if it is not a dry state (step S5, No), it will progress to step S16, and the control part 3 will perform normal operation like a flat ground, and then will go to step S1. Return.

  Then, for example, if the humidity of the cathode gas is measured in step S4, it is determined that the humidity is below a predetermined humidity threshold value, and the dry state is determined. If the humidity exceeds the predetermined humidity threshold value, It is determined that it is not dry.

  For example, if the power generation state is measured in step S4 and the temperature, output voltage, and output current of the fuel cell 5 are measured, the control unit 3 is given the temperature and the output voltage in advance. A database that can output a threshold current of an output current that can be determined whether the altitude is high or not. Based on the measured temperature and output voltage, the controller 3 acquires a corresponding threshold current using a database. And if the measured output current is below a threshold current, it will determine with it being a dry state, and if the measured output current exceeds the threshold current, it will determine with not being a dry state. The control unit 3 may store a database that can output a threshold voltage of an output voltage that can be determined whether or not the vehicle is at a high altitude when temperature and output current are given. Based on the measured temperature and output current, the control unit 3 acquires a corresponding threshold voltage using a database. And if the measured output voltage is below a threshold voltage, it will determine with it being a dry state, and if the measured output voltage exceeds the threshold voltage, it will determine with not being a dry state.

  In step S <b> 6, the control unit 3 performs the discharge control for reducing the water discharge amount on the purge valve 9 and the drain valve 8. In step S6, the discharge control by the purge valve 9 in step S7 and the discharge control by the drain valve 8 in step S8 are performed.

  As shown in FIG. 3A, in the discharge control by the purge valve 9 in step S7, the purge valve 9 is opened at every interval, and the valve opening time is set. And in order to reduce the discharge | emission amount (purge amount) of water in the highland shown in FIG.3 (b) compared with the flat land shown in Fig.3 (a), what is necessary is just to shorten the valve opening time for every interval.

  As shown in FIG. 4A, in the discharge control by the drain valve 8 in step S8, the drain valve 8 is opened at every interval, and the valve opening time in the valve opening is set. And in order to reduce water discharge | emission amount (drain amount) in the highland shown in FIG.4 (b) compared with the flat ground shown in Fig.4 (a), the valve opening time for every interval should just be shortened.

  Then, as shown in FIG. 5, the relationship between the opening time of the drain valve and the purge valve (drain amount, purge amount) with respect to the external air pressure is stored in the control unit 3 as a database. According to this database, it can be set so that the opening time of the drain valve and the purge valve becomes shorter as the external air pressure becomes lower. Note that, for example, 90 kPa or less corresponds to a highland, and if it exceeds 90 kPa, it can be determined that it corresponds to a flat land (step S3). However, as shown in FIG. In addition, by storing the opening times of the drain valve and the purge valve in the database of the control unit 3, it is possible to omit the determination as to whether or not the ground is high in step S3 and the normal operation in step S16. In this case, in the case of a negative determination (No) in the determination of whether or not the drying state in Step S5 and Step S10 which will be described later, it is only necessary to return to Step S1.

  In step S9, as in step S4, the hygrometer 13 measures the humidity of the cathode gas. Alternatively, the power generation state measuring device 5a measures the power generation state. Specifically, the temperature of the fuel cell 5 is measured with the thermometer 16, the output voltage to the load is measured with the voltmeter 17, and the output current to the load is measured with the ammeter 18.

  In step S10, as in step S5, the control unit 3 determines whether or not the cathode side of the fuel cell 5 is in a dry state. If it is a dry state (step S10, Yes), it will progress to step S11, and if it is not a dry state (step S10, No), it will progress to step S16, and the control part 3 will perform normal operation like a flat ground, and then will go to step S1. Return.

  In step S <b> 11, the control unit 3 acquires the discharge state of the anode off gas based on the opening / closing signals of the purge valve 9 and the drain valve 8.

  In step S12, the control unit 3 determines whether or not the anode off gas is being discharged based on the discharge state. If the anode off gas is being discharged (step S12, Yes), the process returns to step S1, and if the anode off gas is not being discharged (step S12, No), the process proceeds to step S13.

  In step S13, the load state measuring device 5b acquires the load state of the fuel cell 5, for example, output power or output current.

  In step S14, the control unit 3 determines whether or not the fuel cell 5 is in a low load state based on the acquired load state. Specifically, if the acquired output power or output current is below a predetermined threshold, it is determined that the load is low, and if the acquired output power or output current exceeds a predetermined threshold, the load is not low. judge.

  In step S15, the control unit 3 performs discharge control for reducing the discharge amount of water by reducing the supply amount of the cathode gas.

  The relationship of the air supply amount (cathode gas supply amount) supplied from the air compressor 11 to the fuel cell 5 with respect to the external air pressure as shown in FIG. 6 is stored in the control unit 3 as a database. According to this database, the air supply amount can be set to decrease as the external air pressure decreases.

1 is a configuration diagram of a fuel cell vehicle according to an embodiment of the present invention. It is a flowchart of the control method in the high ground of the fuel cell vehicle which concerns on embodiment of this invention. (A) is a time chart which shows the opening timing in the flat ground of a purge valve, (b) is a time chart which shows the opening timing in the high ground of a purge valve. (A) is a time chart which shows the opening timing in the flat ground of a drain valve, (b) is a time chart which shows the opening timing in the high ground of a drain valve. It is a graph which shows the relationship of the valve opening time (drain amount, purge amount) of a drain valve and a purge valve with respect to external pressure. It is a graph which shows the relationship of the air supply amount supplied to a fuel cell from an air compressor with respect to external pressure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell vehicle 2 Fuel cell system 3 ECU (control part)
4 External pressure acquisition means 5 Fuel cell (stack)
5a Power generation state measuring device 5b Load state measuring device 6 Ejector 7 Gas-liquid separator (catch tank)
8 Drain valve 9 Purge valve 10 Diluter 11 Air compressor 12 Intercooler 13 Hygrometer 14 Humidifier 15 Back pressure valve 16 Thermometer 17 Voltmeter 18 Ammeter 19 Bypass path

Claims (11)

A fuel cell vehicle including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An external air pressure acquisition means for acquiring an external air pressure of the outside air of the fuel cell vehicle;
A gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell;
A drain valve for discharging the water stored in the gas-liquid separator;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A controller for controlling the discharge of the water discharged from the drain valve,
The fuel cell vehicle according to claim 1, wherein the control unit performs a discharge control for reducing a discharge amount of the water discharged from the drain valve as the external pressure decreases. A fuel cell vehicle including a fuel cell that is supplied with anode gas and cathode gas to generate power,
An external air pressure acquisition means for acquiring an external air pressure of the outside air of the fuel cell vehicle;
A gas-liquid separator that separates moisture from the anode off-gas discharged from the fuel cell;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A purge valve for discharging the anode off-gas after the moisture separation;
A controller for controlling the discharge of the anode off-gas discharged from the purge valve,
The fuel cell vehicle according to claim 1, wherein the control unit performs a discharge control to decrease a discharge amount of the anode off gas discharged from the purge valve as the external pressure decreases. A purge valve for discharging the anode off-gas after the moisture separation;
2. The fuel cell vehicle according to claim 1, wherein the control unit decreases the discharge amount of the anode off-gas discharged from the purge valve as the external pressure decreases in the discharge control. The controller is
Determining whether the cathode gas being supplied to the fuel cell is in a dry state;
The fuel cell vehicle according to any one of claims 1 to 3, wherein the discharge control is performed when it is determined that the cathode gas is in a dry state. A power generation state measuring device for measuring the power generation state of the fuel cell;
The fuel cell according to claim 4, wherein the control unit determines whether or not the cathode gas supplied to the fuel cell is in a dry state based on the measured power generation state. vehicle. Comprising a hygrometer for measuring the humidity of the cathode gas supplied to the fuel cell;
The fuel cell vehicle according to claim 4, wherein the control unit determines whether or not the cathode gas supplied to the fuel cell is in a dry state based on the measured humidity. . The controller is
Determining whether to reduce the amount of cathode gas supplied to the fuel cell;
When it is determined that the cathode gas is in a dry state and the supply amount of the cathode gas is reduced, control is performed to reduce the supply amount of the cathode gas as the external pressure decreases. The fuel cell vehicle according to any one of claims 4 to 6. A load state measuring device for measuring the load state of the fuel cell;
5. The fuel cell vehicle according to claim 4, wherein the control unit determines to reduce the supply amount of the cathode gas when the measured load state is smaller than a load state threshold. A diluter for diluting and discharging the anode off gas with the cathode off gas discharged from the fuel cell;
The controller is
Determining whether the anode off-gas has been exhausted;
The fuel cell vehicle according to claim 4, wherein when it is determined that the anode off gas is not discharged, it is determined that the supply amount of the cathode gas is reduced. A fuel cell that is supplied with anode gas and cathode gas to generate power;
An outside air pressure acquisition means for acquiring the outside air pressure of the fuel cell vehicle;
A gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell;
A drain valve for discharging the water stored in the gas-liquid separator;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A control unit for controlling the discharge of the water discharged from the drain valve, in a high altitude of a fuel cell vehicle,
A control method in a high altitude of a fuel cell vehicle, wherein the control unit performs discharge control for reducing the discharge amount of the water discharged from the drain valve as the outside air pressure decreases. A fuel cell that is supplied with anode gas and cathode gas to generate power;
An outside air pressure acquisition means for acquiring the outside air pressure of the fuel cell vehicle;
A gas-liquid separator that separates moisture from the anode off-gas discharged from the fuel cell;
A bypass path for returning the anode off-gas after the moisture separation to an anode supply path for supplying the anode gas to the fuel cell;
A purge valve for discharging the anode off-gas after the moisture separation;
A control unit for controlling the discharge of the anode off-gas discharged from the purge valve at a high altitude of a fuel cell vehicle,
A control method in a high altitude of a fuel cell vehicle, wherein the control unit performs a discharge control to decrease a discharge amount of the anode off-gas discharged from the purge valve as the external pressure decreases.

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