JP5255338B2 - Fuel cell system and control method in case of failure - Google Patents

Description

  The present invention relates to a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas and generates power, and a control method in the event of a failure.

  In the fuel cell, when power is generated, the anode gas and the cathode gas chemically react to generate water. This moisture stays in the gas flow paths of the anode gas and the cathode gas of the fuel cell, closes the gas flow path, and causes so-called flooding. Flooding hinders the progress of the chemical reaction and lowers the output voltage of the fuel cell.

  Therefore, in order to discharge moisture from the anode and cathode gas flow paths, a purge valve is provided in the anode off-gas flow path discharged from the fuel cell, and together with the anode off-gas by opening the purge valve. The water can be discharged and the water can be purged. However, the purge valve, as well as other parts, does not necessarily fail, and a fail-safe concept that assumes a failure has been proposed. If the purge valve breaks down, flooding occurs, so the purge valve needs to be repaired, but a fuel cell system control method that allows a fuel cell vehicle equipped with the fuel cell system to self-propelled to a service factory is proposed (For example, see Patent Document 1 and Patent Document 2).

Further, when the purge valve is opened, unreacted anode gas contained in the anode off-gas is also discharged. Therefore, in order to discharge moisture while reusing the unreacted anode gas, a circulation path, a gas-liquid separator, and a drain are used. A valve is attached to the purge valve. Since moisture is flowed from the fuel cell to the anode off-gas flow path and accumulated in the gas-liquid separator, and the accumulated moisture is discharged from the drain valve, the frequency of moisture purge (anode off-gas discharge) by the purge valve can be reduced. However, since the flooding occurs when the purge valve fails, the purge valve needs to be repaired. Therefore, if repair is not possible immediately, opening the drain valve not only discharges the water stored in the gas-liquid separator, but also purges the water remaining in the anode gas path and anode. A fuel cell system control method has been proposed (see, for example, Patent Document 3).
JP 2006-156282 A JP 2003-92125 A JP 2007-35436 A

  However, in the conventional control method, although it is a temporary travel at the time of failure, the power output from the fuel cell may not be sufficient for the travel, which may adversely affect drivability. In addition, failure can occur not only with the purge valve but also with the drain valve. Therefore, even if the drain valve breaks down based on the fail-safe concept, the power output from the fuel cell is ensured by the amount necessary for driving and is good. Must have a good drivability.

  In view of the above, the present invention provides a fuel cell system and a fuel cell system that can secure electric power output from a fuel cell as much as necessary for traveling and realize good drivability when a purge valve or a drain valve fails. It aims at providing the control method at the time of failure of.

The present invention relates to a fuel cell system including a fuel cell that is supplied with an anode gas and a cathode gas and generates electric power.
A gas-liquid separator that separates and stores water from the anode off-gas discharged from the fuel cell, a drain valve that discharges the water stored in the gas-liquid separator, and the anode off-gas after the water separation, A bypass for returning to the anode supply path for supplying the anode gas to the fuel cell; a control unit for controlling a valve opening time of the drain valve; a purge valve for discharging the anode off-gas after the moisture separation; and the purge A failure determination unit that determines whether or not the valve has failed, and a power generation state measurement device that measures a power generation state of the fuel cell,
When the failure determination unit determines that the purge valve has failed, the control unit controls to increase the valve opening time of the drain valve from before the determination, and whether the power generation state has reached a state threshold value And determining the supply amount of the cathode gas to be supplied to the fuel cell when the power generation state has not reached the state threshold value, after the opening time of the drain valve is increased. It is characterized by controlling to increase more than before.

  According to the present invention, since the anode off gas can be continuously discharged after the moisture stored in the gas-liquid separator is discharged by increasing the valve opening time of the drain valve, the drain valve also functions as a purge valve that has failed. I can also serve. Prior to increasing the supply amount of cathode gas, increasing the drain valve opening time is because the deterioration of the fuel cell due to drying after excessive drainage of water at the drain valve is caused by excessive increase in the supply amount of cathode gas. This is because it is smaller than the deterioration of the fuel cell due to drying. That is, the options are selected in order from the lowest risk of deterioration of the fuel cell. Further, by increasing the opening time of the drain valve, the increase in the supply amount of the cathode gas can be reduced, and the supply amount of the cathode gas can be increased without deteriorating the fuel cell. The state threshold is a value of the start completion voltage for determining whether or not the start is normally completed, and it is determined that stable operation of the fuel cell is possible when this value is exceeded.

  Strictly speaking, 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. For this reason, when the supply amount of the cathode gas is increased, the moisture remaining in the cathode gas flow passage can be pushed out (purged) and discharged to the outside more than when no failure has occurred. In this way, reducing the moisture remaining in the cathode gas flow channel and the cathode not only reduces the amount of moisture diffusing from the cathode to the anode, but also reverses the concentration gradient of the moisture and lowers the moisture concentration at the cathode than at the anode. Therefore, the water once diffused to the anode can be returned to the cathode by back diffusion (back diffusion). And the water | moisture content in the gas flow path of an anode and anode gas can be reduced. As a result, the interval between the opening of the purge valve and the drain valve becomes longer, so it is not necessary to perform the opening of the purge valve during the time of self-running to the service factory. Operation close to normal operation is possible.

Further, in the present invention, when the failure determination unit determines that the purge valve has failed , the control unit increases the opening time of the drain valve as compared to before the determination, and at each interval of the drain valve. After gradually increasing the valve opening time, determining whether the power generation state has reached a state threshold value for determining the power generation state of the fuel cell, and gradually increasing the valve opening time of the drain valve, Preferably, when the power generation state does not reach the state threshold, the supply amount of the cathode gas supplied to the fuel cell is increased from before the determination .

In the present invention, the control unit controls to increase the supply amount of the cathode gas supplied to the fuel cell more than before the determination, and then determines again whether the power generation state has reached the state threshold value. When the power generation state does not reach the state threshold value in the determination again, it is preferable to reduce the state threshold value and reduce the upper limit value of the electric power that the fuel cell supplies to the load.
Since the start threshold voltage can be set low by reducing the state threshold or by reducing the upper limit value of the power supplied to the load by the fuel cell, the chemical reaction in the fuel cell is limited, so that it is generated. The amount of moisture remaining in the anode gas path and the anode can be reduced. As a result, the interval between the opening of the purge valve and the drain valve can be lengthened, so that it is not necessary to perform the opening of the purge valve during the time of self-propelling to the service factory. Operation close to normal operation is possible.

Further, the present invention provides a fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
A gas-liquid separator that separates and stores water from the anode off-gas discharged from the fuel cell, a drain valve that discharges the water stored in the gas-liquid separator, and the anode off-gas after the water separation, A bypass for returning to the 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 a valve opening time of the purge valve, and the drain A failure determination unit that determines whether or not the valve has failed, and a power generation state measurement device that measures a power generation state of the fuel cell ,
When the failure determination unit determines that the drain valve has failed, the control unit controls to increase the valve opening time of the purge valve from before the determination , and the power generation state is the power generation state of the fuel cell. After determining whether or not the state threshold value is reached and increasing the purge valve opening time, the fuel cell is supplied to the fuel cell when the power generation state has not reached the state threshold value. Control is performed to increase the supply amount of the cathode gas before the determination .

According to the present invention, by increasing the opening time of the purge valve, the anode off-gas can be continuously discharged after part of the water stored in the gas-liquid separator is discharged. It can also serve as a function.
Further, when the supply amount of the cathode gas is increased, more moisture remaining in the cathode gas gas passage can be pushed out (purged) and discharged to the outside than when no failure has occurred. Thus, by reducing the moisture remaining in the cathode gas channel and the cathode, the moisture diffused from the cathode to the anode can be reduced, and the moisture diffused to the anode can be returned to the cathode by back diffusion. And the water | moisture content in the gas flow path of an anode and anode gas can be reduced. As a result, the interval between the opening of the purge valve and the drain valve can be lengthened, so that it is not necessary to perform the opening of the drain valve during the self-propelled operation to the service factory. Operation close to normal operation is possible.

Further, in the present invention, when the failure determination unit determines that the drain valve has failed, the control unit increases the opening time of the purge valve from before the determination, and at each interval of the purge valve. After gradually increasing the valve opening time, determining whether the power generation state has reached a state threshold value for determining the power generation state of the fuel cell, and gradually increasing the valve opening time of the purge valve. When the power generation state does not reach the state threshold value, it is preferable that the supply amount of the cathode gas supplied to the fuel cell is controlled to be increased from before the determination.

  In the present invention, the control unit controls to increase the supply amount of the cathode gas supplied to the fuel cell more than before the determination, and then determines again whether the power generation state has reached the state threshold value. When the power generation state does not reach the state threshold value in the determination again, it is preferable to reduce the state threshold value and reduce the upper limit value of the electric power that the fuel cell supplies to the load.

  Since the start threshold voltage can be set low by reducing the state threshold or by reducing the upper limit value of the power supplied to the load by the fuel cell, the chemical reaction in the fuel cell is limited, so that it is generated. Thus, the amount of moisture remaining in the anode gas flow path and the anode can be reduced. As a result, the interval between the opening of the purge valve and the drain valve becomes longer, so it is not necessary to perform the opening of the drain valve during the time of self-propelling to the service factory. Operation close to normal operation is possible.

Further, in the present invention, after the supply of the anode gas at the time of scavenging is stopped, the valve is opened, and a scavenging introduction valve for supplying the cathode gas to the fuel cell instead of the anode gas, and the scavenging at the time of the scavenging A scavenging discharge valve that opens after the anode gas supply is stopped, and discharges the anode gas from the fuel cell without going through the gas-liquid separator;
When the failure determination unit determines that both the purge valve and the drain valve have failed, the control unit opens the scavenging discharge valve while supplying the anode gas to the fuel cell. It is preferable to control so that it does. Even when the scavenging discharge valve is opened, the anode off-gas is discharged, but moisture can be purged and flooding can be prevented.

  Further, in the present invention, the fuel cell system includes a pressure gauge that measures the pressure in the fuel cell, and the failure determination unit controls the opening of the purge valve for a predetermined time when the fuel cell is stopped, It is preferable to determine whether or not a decrease pressure of the pressure in the fuel cell before and after the opening of the purge valve exceeds a pressure threshold value. Further, in the present invention, the fuel cell system includes a pressure gauge that measures the pressure in the fuel cell, and the failure determination unit controls the opening of the drain valve for a predetermined time when the fuel cell is stopped, It is preferable to determine whether or not a decrease pressure of the pressure in the fuel cell before and after the drain valve is opened exceeds a pressure threshold value.

  According to the present invention, when the fuel cell is stopped, that is, when the fuel cell system is stopped, the gas flow path in the fuel cell is sealed at a pressure higher than atmospheric pressure by scavenging or the like. When the drain valve opens and closes normally and the gas is released into the atmosphere and the pressure in the fuel cell decreases, it can be determined that the purge valve and the drain valve are not malfunctioning. Conversely, by measuring the pressure decrease, it can be determined whether or not the purge valve and the drain valve have failed. If the pressure does not exceed the pressure threshold, it can be determined that there is a failure. . In addition, before the pressure in the fuel cell is reduced to the atmospheric pressure, the purge valve failure determination and the drain valve failure determination can be performed separately.

  In the present invention, the fuel cell system includes a voltmeter that measures a voltage output from the fuel cell, and the failure determination unit controls the purge valve to open for a predetermined time when the fuel cell is activated. It is preferable that the inside of the fuel cell is replaced with an anode gas, and it is determined whether or not the voltage after the opening of the purge valve exceeds a voltage threshold value. In the present invention, the fuel cell system includes a voltmeter that measures a voltage output from the fuel cell, and the failure determination unit controls the drain valve to open for a predetermined time when the fuel cell is activated. It is preferable to replace the inside of the fuel cell with anode gas and determine whether or not the voltage after the drain valve is open exceeds a voltage threshold value.

  According to the present invention, when the fuel cell is started, that is, when the fuel cell system is started, the inside of the fuel cell is replaced with the anode gas, so that the output voltage of the fuel cell increases. In order to replace the inside of the fuel cell with the anode gas, it is necessary not only to introduce the anode gas into the fuel cell but also to open the purge valve and the drain valve to discharge the gas enclosed in the fuel cell. is there. From this, conversely, it can be confirmed that the gas enclosed in the fuel cell is discharged from the rise in the output voltage of the fuel cell, and the purge valve and the drain valve are opened. If the output voltage does not exceed the voltage threshold value, it can be determined that the valve is not fully opened and a failure has occurred.

The present invention also provides a fuel cell that generates power by being supplied with an anode gas and a cathode gas, a gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell, and the gas-liquid separator. A drain valve for discharging the stored water, 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 a valve opening time of the drain valve are controlled. A control unit that performs the operation, a purge valve that discharges the anode off-gas after the water separation, a failure determination unit that determines whether or not the purge valve has failed, and a power generation state measurement device that measures the power generation state of the fuel cell A control method at the time of failure of a fuel cell system comprising:
When the failure determination unit determines that the purge valve has failed, the control unit controls to increase the valve opening time of the drain valve from before the determination, and the power generation state is the power generation state of the fuel cell. After determining whether or not the state threshold value is reached and increasing the opening time of the drain valve , the fuel cell is supplied to the fuel cell when the power generation state has not reached the state threshold value. Control is performed to increase the supply amount of the cathode gas before the determination.

  As described above, according to the present invention, by increasing the opening time of the drain valve, the anode off gas can be continuously discharged after the water stored in the gas-liquid separator is discharged. It can also serve as a function. In addition, reducing the moisture accumulated in the cathode gas channel and the cathode not only reduces the moisture diffusing from the cathode to the anode, but also reverses the moisture concentration gradient so that the moisture concentration is lower at the cathode than at the anode. Therefore, the water once diffused to the anode can be returned to the cathode by back diffusion. And the water | moisture content in the gas flow path of an anode and anode gas can be reduced. As a result, the interval between the opening of the purge valve and the drain valve becomes longer, so it is not necessary to perform the opening of the purge valve during the time of self-running to the service factory. Operation close to normal operation is possible.

The present invention also provides a fuel cell that generates power by being supplied with an anode gas and a cathode gas, a gas-liquid separator that separates and stores moisture from the anode off-gas discharged from the fuel cell, and the gas-liquid separator. A drain valve for discharging the stored water, 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 an anode off-gas after the moisture separation. A purge valve that discharges, a control unit that controls a valve opening time of the purge valve, a failure determination unit that determines whether or not the drain valve has failed, and a power generation state measurement device that measures a power generation state of the fuel cell When a control method at the time of failure of the fuel cell system equipped with,
When the failure determination unit determines that the drain valve has failed, the control unit controls to increase the valve opening time of the purge valve from before the determination , and the power generation state is the power generation state of the fuel cell. After determining whether or not the state threshold value is reached and increasing the purge valve opening time, the fuel cell is supplied to the fuel cell when the power generation state has not reached the state threshold value. Control is performed to increase the supply amount of the cathode gas before the determination .

  According to the present invention, by increasing the opening time of the purge valve, the anode off-gas can be continuously discharged after part of the water stored in the gas-liquid separator is discharged. It can also serve as a function.

  ADVANTAGE OF THE INVENTION According to this invention, when a purge valve or a drain valve breaks down, the electric power output from a fuel cell is ensured for driving | running | working, and the failure of a fuel cell system and fuel cell system which can implement | achieve favorable drivability Can provide time control method.

  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 system 1 according to an embodiment of the present invention. The fuel cell system 1 includes a fuel cell (stack) 5 that is supplied with anode gas and 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 1 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 reduced and the reaction efficiency of anode gas is increased.

  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 returns to the anode, so that drying of the anode can be prevented. Note that this can be used to prevent flooding. Discharging the anode off-gas not only directly purges moisture, but also drains the anode off-gas, so that dry uncirculated anode gas is used instead. , Supplied from a high-pressure hydrogen tank or the like, deprives the anode of moisture, and reduces the accumulated moisture.

  The anode off-gas after the moisture separation is discharged outside the fuel cell system 1 via the diluter 10 when the purge valve 9 is opened. When the purge valve 9 is opened, the pressure in the gas path of the anode gas of the fuel cell 5 being pressurized is lowered at once, and an air flow is generated, so that the moisture remaining in the gas path and anode of the fuel cell 5 is retained. It can be purged and discharged to the outside.

  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 1, 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, humidifying the cathode gas can prevent drying of the cathode. When the cathode gas is increased, it goes in the direction of drying. 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 1 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, the drain valve 8, and the scavenging discharge valve 13 with the cathode off gas, and discharges it to the outside.

  Further, the fuel cell system 1 includes a scavenging introduction valve 18 that opens the valve after the supply of anode gas during scavenging is stopped and supplies the cathode gas to the fuel cell 5 instead of the anode gas, and an anode gas during scavenging. And the scavenging discharge valve 13 for discharging the anode gas from the fuel cell 5 without going through the gas-liquid separator 7.

  Further, the fuel cell system 1 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 5 a includes a thermometer 16 that measures the temperature of the fuel cell 5 and a voltmeter 17 that measures the output voltage of the fuel cell 5, and an ammeter that measures the output current of the fuel cell 5. Also good. The fuel cell system 1 is provided with a pressure gauge 20 that measures the pressure in the gas flow path of the anode gas of the fuel cell 5.

  The fuel cell system 1 includes an ECU (electronic control unit) 2, and the ECU 2 includes a control unit 3 and a failure determination unit 4. Although details will be described later, the control unit 3 can control the opening time of the drain valve 8 and the purge valve 9, and the failure determination unit 4 can determine whether or not the drain valve 8 and the purge valve 9 have failed.

  FIG. 2 shows a flowchart of a control method at the time of failure of the fuel cell system 1 according to the embodiment of the present invention.

  First, in step S1, for example, when the fuel cell system 1 is mounted on a vehicle, the control unit 3 determines whether or not the ignition switch (IG) is turned on. If the ignition switch is turned on (step S1, Yes), the process proceeds to step S2. If the ignition switch is not turned on (step S1, No), the control method at the time of failure of the fuel cell system 1 is stopped.

  Next, in step S2, the failure determination unit 4 determines whether or not the purge valve 9 has failed. The failure determination method by the failure determination unit 4 is the same for both the purge valve 9 and the drain valve 8. The failure determination unit 4 controls the opening of the purge valve 9 and the drain valve 8 for a predetermined time when the fuel cell 5 is stopped. And determining whether or not the reduced pressure of the pressure in the fuel cell 5 (measured by the pressure gauge 20 in FIG. 1) before and after the opening of the purge valve 9 and the drain valve 8 exceeds the pressure threshold value. Judgment is made. If the decrease pressure exceeds the pressure threshold, it is determined that there is no failure, and if the decrease pressure does not exceed the pressure threshold, it is determined that there is a failure.

  Further, a failure determination method described later may be employed, and the failure determination unit 4 controls opening of the purge valve 9 and the drain valve 8 for a predetermined time when the fuel cell 5 is started, and uses the anode gas for the fuel cell 5. It is determined whether or not the output voltage (measured by the voltmeter 17 in FIG. 1) after the purge valve 9 and the drain valve 8 are open exceeds the voltage threshold value. If the output voltage exceeds the voltage threshold, it is determined that there is no failure, and if the output voltage does not exceed the voltage threshold, it is determined that there is a failure.

  If the purge valve 9 has failed (step S2, Yes), the process proceeds to step S4. If the purge valve 9 has not failed (step S2, No), the process proceeds to step S3.

  In step S4, the failure determination unit 4 determines whether or not the drain valve 8 has failed. If the drain valve 8 has failed (step S4, Yes), the process proceeds to step S5. If the drain valve 8 has not failed (step S4, No), the process proceeds to step S8.

  In step S8, although the purge valve 9 has failed but the drain valve 8 has not failed, the control unit 3 increases the valve opening time of the drain valve 8 from before the failure determination.

  FIG. 3 shows the state of the fuel cell system 1 when the purge valve 9 is closed. The drain valve 8 is disposed at a lower height than the purge valve 9. The height connected to the gas-liquid separator 7 is also lower in the drain valve 8 than in the purge valve 9. The scavenging exhaust valve 13 is disposed higher than the drain valve 8 and the purge valve 9. Also, the pipe connecting the fuel cell 5 and the gas-liquid separator 7 is arranged so as to become lower as it approaches the gas-liquid separator 7 from the fuel cell 5, and the liquefied moisture from the fuel cell 5 to the gas-liquid separator 7 is arranged. It is designed not to interfere with the move to. Similarly, the pipes connected to both ends of the purge valve 9 are also arranged so as to become lower toward the diluter 10 from the gas-liquid separator 7, and movement of liquefied water from the gas-liquid separator 7 to the diluter 10 is performed. Is not disturbed.

  And as shown in FIG. 3, the water | moisture content stored in the gas-liquid separator 7 is discharged | emitted by increasing the valve opening time of the drain valve 8, and the water level of the water | moisture content stored to the height of the piping which the drain valve 8 connects to Since the anode off-gas can be continuously discharged after being lowered, the drain valve 8 can also function as the purge valve 9 that has failed.

  As shown in FIG. 4 (a), since the amount of moisture generated per hour is constant, both the purge valve 9 and the drain valve 8 are opened at intervals, and the valve opening time in the valve opening is Is set. In order to increase the valve opening time of the drain valve 8, the same applies to the case of increasing the valve opening time of the purge valve 9, which will be described later. However, as shown in FIG. Should be lengthened. Further, as shown in FIG. 4B to FIG. 4C, it is also effective to change and increase the valve opening time for each interval with the transition of time. When the valve opening time finally matches the interval time, the normally open state can be fixed to the fully open state. If the valve opening time is gradually lengthened in this way, it may be possible to supply power before the valve is fully opened, so that it is more difficult to dry the anode than when the valve is fully opened from the beginning. it can.

  In step S5, since both the purge valve 9 and the drain valve 8 are out of order, the control unit 3 opens the scavenging exhaust valve 13 during the supply of the anode gas to the fuel cell 5. Even when the scavenging discharge valve 13 is opened, the anode off-gas is discharged, but moisture can be purged and flooding can be prevented.

  In step S3, the failure determination unit 4 determines whether or not the drain valve 8 has failed. If the drain valve 8 has failed (step S3, Yes), the process proceeds to step S6. If the drain valve 8 has not failed (step S3, No), both the purge valve 9 and the drain valve 8 have failed. There is no state, and the process proceeds to step S9.

  In step S <b> 6, the control unit 3 determines whether or not it is necessary to open the valve to discharge moisture from the drain valve 8. The control unit 3 stores whether or not scavenging is performed when the fuel cell system 1 is stopped immediately before. The control unit 3 determines that the drain valve 8 is not required to be opened when scavenging is performed when the immediately preceding fuel cell system 1 is stopped, and if the scavenging is not performed when the immediately preceding fuel cell system 1 is stopped, the drain valve 8 8 is determined to be required. If it is not necessary to open the drain valve 8 (step S6, unnecessary), the process proceeds to step S9. If it is necessary to open the drain valve 8 (step S7, necessary), the process proceeds to step S7.

  In step S7, the drain valve 8 has failed, but the purge valve 9 has not failed. Therefore, the control unit 3 increases the opening time of the purge valve 9 from before the failure determination.

  FIG. 5 shows the state of the fuel cell system 1 when the drain valve 8 is closed. As shown in FIG. 5, by increasing the valve opening time of the purge valve 9, the water stored in the gas-liquid separator 7 is discharged, and the water level of the stored water is lowered to the height of the pipe connected to the purge valve 9. Since the anode off-gas can subsequently be discharged later, the purge valve 9 can also function as the failed drain valve 8.

  In step S9, the power generation state measurement device 5a measures the power generation state of the fuel cell 5. Specifically, the stack voltage (OCV: open circuit voltage) is measured by the voltmeter 17, the temperature of the fuel cell 5 is measured by the thermometer 16, and the output current is measured by the ammeter as necessary.

  In step S10, the control unit 3 determines whether or not the power generated by the fuel cell 5 can be supplied to the load based on the measured power generation state. If power supply is possible (step S10, Yes), the process proceeds to step S11. If power supply is not possible (step S10, No), the process proceeds to step S12. Specifically, it is determined whether or not the power generation state (stack voltage) has reached a state threshold (startup completion voltage). If it has reached, it is determined that power can be supplied, and if it has not reached, it is determined that power cannot be supplied. A value obtained by correcting the measured stack voltage with the measured temperature of the fuel cell 5 may be used for the determination. Moreover, when restrict | limiting the output of the fuel cell 5 mentioned later, it can restrict | limit based on the output electric power calculated from the stack voltage and the measured output current.

  In step S <b> 11, for example, the control unit 3 transmits a power supply start signal to turn on the contactor, and stops the control method when the fuel cell system 1 fails.

  In step S12, the supply amount of the cathode gas is increased from before the failure determination. When the supply amount of the cathode gas is increased, the moisture staying in the cathode gas flow path can be discharged (purged). In this way, if the moisture staying in the cathode gas channel and the cathode is reduced, the moisture concentration gradient is reversed and the moisture concentration is lower at the cathode than at the anode, so that the moisture diffused to the anode is back-diffused (FIG. 1). It can be returned to the cathode by reference, back diffusion). And the water | moisture content in the gas flow path of an anode and anode gas can be reduced. As a result, the interval between the opening of the purge valve 9 and the drain valve 8 becomes longer, so that the opening of the purge valve 9 and the drain valve 8 does not have to be performed during the time of self-running to the service factory. Despite the failure of the fuel cell 9 and the drain valve 8, the power output from the fuel cell 5 can be ensured by the amount necessary for traveling, and operation close to normal operation is possible. And you can achieve good drivability

  In step S13, as in step S9, the power generation state measurement device 5a measures the power generation state of the fuel cell 5.

  In step S14, as in step S10, the control unit 3 determines whether or not the electric power generated by the fuel cell 5 can be supplied to the load based on the measured power generation state. If power can be supplied (step S14, Yes), the process proceeds to step S11. If power cannot be supplied (step S14, No), the process proceeds to step S15.

  When the failure determination unit 4 determines that the purge valve 9 or the drain valve 8 has not failed in step S15, the control unit 3 reduces the state threshold and the power and current that the fuel cell 5 supplies to the load. Limit and reduce. Specifically, the control unit 3 generates (ON) an output restriction signal of the fuel cell 5 and performs the restriction based on the output restriction signal. Since the electrochemical reaction in the fuel cell 5 is limited by reducing the state threshold or reducing the power supplied to the load by the fuel cell 5, the generated water is reduced, and the anode gas flow path and The amount of water staying at the anode can be reduced. As a result, the opening interval between the purge valve 9 and the drain valve 8 can be set longer, so that when the travel distance is not long, the opening of the purge valve 9 and the drain valve 8 is not performed during the time during which the service factory self-runs. In spite of the failure of the purge valve 9 and the drain valve 8, the operation close to the normal operation becomes possible.

  In step S16, as in step S9, the power generation state measurement device 5a measures the power generation state of the fuel cell 5.

  In step S17, as in step S10, the control unit 3 determines whether or not the electric power generated by the fuel cell 5 can be supplied to the load based on the measured power generation state. If power supply is possible (step S17, Yes), the process proceeds to step S11. If power supply is not possible (step S17, No), the process proceeds to step S18.

  In step S18, the control unit 3 warns the user of the fuel cell system 1 by displaying, for example, on the display unit that the fuel cell 5 is not in a state in which power can be supplied to the load. Stop the method.

  FIG. 6 shows an example of a time chart when the purge valve 9 is closed. Until step S8, the stack voltage (output voltage of the fuel cell 5) has not increased due to the failure of the purge valve 9, as shown in FIG. After step S8, as shown in FIG. 6B, the valve opening time of the drain valve 8 is increased. In step S10, as shown in FIG. 6 (a), the stack voltage has not reached the start completion voltage (state threshold), so in step S12 and thereafter, as shown in FIG. 6 (c), the increase of the air compressor 11 is increased. The supply time of the cathode gas is increased by increasing the ON time of the speed signal. In step S14, as shown in FIG. 6 (a), the stack voltage has not reached the start completion voltage. Therefore, in step S15 and thereafter, as shown in FIG. 6 (d), the output restriction signal of the fuel cell 5 is turned on. (ON), and the start completion voltage (state threshold) is reduced as shown in FIG. In step S17, as shown in FIG. 6 (a), the stack voltage reaches the reduced start-up completion voltage. In step S11, as shown in FIG. 6 (e), a power generation permission command signal (power supply start signal) is sent. The power supply from the fuel cell 5 to the load can be started by turning it on.

  FIG. 7 shows an example of a time chart when the drain valve 8 is closed. Until step S7, the stack voltage (the output voltage of the fuel cell 5) has not increased due to the failure of the drain valve 8, as shown in FIG. After step S7, as shown in FIG. 7B, the opening time of the purge valve 9 is increased. In step S10, as shown in FIG. 7A, the stack voltage has not reached the start completion voltage (state threshold), so in step S12 and thereafter, as shown in FIG. The supply time of the cathode gas is increased by increasing the ON time of the speed signal. In step S14, as shown in FIG. 7A, the stack voltage has not reached the start completion voltage, so in step S15 and later, as shown in FIG. 7D, the output restriction signal of the fuel cell 5 is turned on. (ON), and as shown in FIG. 7A, the start completion voltage (state threshold) is reduced. In step S17, as shown in FIG. 7A, the stack voltage reaches the reduced start completion voltage. In step S11, as shown in FIG. 7E, a power generation permission command signal (power supply start signal) is sent. The power supply from the fuel cell 5 to the load can be started by turning it on.

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a flowchart of the control method at the time of failure of the fuel cell system which concerns on embodiment of this invention. FIG. 3 is a layout diagram of main valves of a fuel cell system showing a state of the fuel cell system when a purge valve closing failure occurs. (A) is a time chart showing the normal opening timing of the valve (purge valve, drain valve), (b) is a time chart showing the opening timing of the valve (purge valve, drain valve) increased in frequency, ( c) is a time chart showing the opening timing at which the frequency of the valves (purge valve, drain valve) is maximized (MAX). FIG. 3 is an arrangement diagram of main valves of a fuel cell system showing a state of the fuel cell system at the time of a drain valve closing failure. It is a time chart at the time of a purge valve closing failure, (a) is a graph which shows transition of the stack voltage of the fuel cell at the time of starting, (b) shows the opening timing of a drain valve, (c) is an air compressor. The transmission timing of the acceleration signal is shown, (d) shows the transmission timing of the output restriction signal of the fuel cell, and (e) shows the transmission timing of the power generation permission command signal. It is a time chart at the time of a drain valve acceleration close failure, (a) is a graph which shows transition of the stack voltage of the fuel cell at the time of starting, (b) shows the opening timing of a purge valve, (c) is air The timing of transmission of the acceleration signal of the compressor is shown, (d) shows the timing of transmission of the output limit signal of the fuel cell, and (e) shows the timing of transmission of the power generation permission command signal.

Explanation of symbols

1 Fuel cell system 2 ECU
3 Control unit 4 Failure determination unit 5 Fuel cell (stack)
5a Power generation 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 Scavenging exhaust valve 14 Humidifier 15 Back pressure valve 16 Thermometer 17 Voltmeter 18 Scavenging introduction valve 19 Bypass path 20 Pressure gauge

Claims (13)

In a fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
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 opening time of the drain valve;
A purge valve for discharging the anode off-gas after the moisture separation;
A failure determination unit for determining whether or not the purge valve has failed;
A power generation state measuring device for measuring the power generation state of the fuel cell,
The controller is
When the failure determination unit determines that the purge valve has failed, it controls to increase the valve opening time of the drain valve from before the determination,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell;
Control is performed to increase the supply amount of the cathode gas supplied to the fuel cell from before the determination when the drain valve opening time is increased and the power generation state does not reach the state threshold. A fuel cell system. The controller is
When the failure determination unit determines that the purge valve has failed, while increasing the valve opening time of the drain valve than before the determination, gradually increasing the valve opening time for each interval of the drain valve,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell;
After gradually increasing the valve opening time of the drain valve, when the power generation state does not reach the state threshold, the supply amount of the cathode gas supplied to the fuel cell is increased from before the determination. The fuel cell system according to claim 1, wherein the fuel cell system is controlled as follows. The controller is
After controlling to increase the supply amount of the cathode gas supplied to the fuel cell from before the determination, it is determined again whether the power generation state has reached the state threshold,
In the determination again, when the power generation state has not reached the state threshold,
3. The fuel cell system according to claim 1, wherein the state threshold value is decreased and an upper limit value of electric power supplied to the load by the fuel cell is decreased. In a fuel cell system including a fuel cell that is supplied with anode gas and cathode gas to generate power,
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 purge valve for discharging the anode off-gas after the moisture separation;
A control unit for controlling a valve opening time of the purge valve;
A failure determination unit for determining whether or not the drain valve has failed ;
A power generation state measuring device for measuring the power generation state of the fuel cell,
The controller is
When the failure determination unit determines that the drain valve has failed , control to increase the valve opening time of the purge valve from before the determination ,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell;
Control is performed so that the supply amount of the cathode gas supplied to the fuel cell is increased from that before the determination when the purge valve opening time is increased and the power generation state does not reach the state threshold. A fuel cell system. The controller is
When the failure determination unit determines that the drain valve has failed, the valve opening time of the purge valve is increased more than before the determination, and the valve opening time for each interval of the purge valve is gradually increased,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell;
After gradually increasing the opening time of the purge valve, when the power generation state does not reach the state threshold, the supply amount of the cathode gas supplied to the fuel cell is increased from before the determination. The fuel cell system according to claim 4, wherein the fuel cell system is controlled as follows. The controller is
After controlling to increase the supply amount of the cathode gas supplied to the fuel cell from before the determination, it is determined again whether the power generation state has reached the state threshold,
In the determination again, when the power generation state has not reached the state threshold,
The fuel cell system according to claim 4 or claim 5 wherein the condition threshold is reduced, the fuel cell is characterized in that to reduce the upper limit value of power supplied to the load. A scavenging introduction valve for opening the valve after supply of the anode gas during scavenging and supplying the cathode gas to the fuel cell instead of the anode gas;
A scavenging discharge valve that opens after the supply of the anode gas during the scavenging, and discharges the anode gas from the fuel cell without going through the gas-liquid separator,
When the failure determination unit determines that both the purge valve and the drain valve have failed, the control unit opens the scavenging discharge valve while supplying the anode gas to the fuel cell. The fuel cell system according to any one of claims 1 to 6 , wherein the fuel cell system is controlled to perform. A pressure gauge for measuring the pressure in the fuel cell;
The failure determination unit
When the fuel cell is stopped, the purge valve is controlled to open for a predetermined time,
Decrease pressure in the pressure within the fuel cell before and after the opening of the purge valve, according to any one of claims 1 to 3, characterized in that to determine whether it exceeds a pressure threshold Fuel cell system. A pressure gauge for measuring the pressure in the fuel cell;
The failure determination unit
When the fuel cell is stopped, the drain valve is controlled to open for a predetermined time,
Decrease pressure in the pressure within the fuel cell before and after the opening of the drain valve, according to any one of claims 4 to 6, characterized in that to determine whether it exceeds a pressure threshold Fuel cell system. A voltmeter for measuring a voltage output from the fuel cell;
The failure determination unit
When the fuel cell is started, the purge valve is controlled to open for a predetermined time, and the inside of the fuel cell is replaced with anode gas.
The fuel cell system according to any one of claims 1 to 3 wherein the voltage after opening of the purge valve, and judging whether or exceeds the voltage threshold. A voltmeter for measuring a voltage output from the fuel cell;
The failure determination unit
When the fuel cell is activated, the drain valve is controlled to open for a predetermined time, and the inside of the fuel cell is replaced with an anode gas.
The fuel cell system according to any one of claims 4 to 6 , wherein it is determined whether or not the voltage after the drain valve is opened exceeds a voltage threshold value. A fuel cell that is supplied with anode gas and cathode gas to generate power;
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 opening time of the drain valve;
A purge valve for discharging the anode off-gas after the moisture separation;
A failure determination unit for determining whether or not the purge valve has failed;
A power generation state measuring device for measuring a power generation state of the fuel cell, and a control method at the time of failure of the fuel cell system,
The controller is
When the failure determination unit determines that the purge valve has failed, it controls to increase the valve opening time of the drain valve from before the determination,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell ;
Control is performed to increase the supply amount of the cathode gas supplied to the fuel cell from before the determination when the drain valve opening time is increased and the power generation state does not reach the state threshold. A control method in the event of a failure of a fuel cell system. A fuel cell that is supplied with anode gas and cathode gas to generate power;
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 purge valve for discharging the anode off-gas after the moisture separation;
A control unit for controlling a valve opening time of the purge valve;
A failure determination unit for determining whether or not the drain valve has failed ;
A power generation state measuring device for measuring a power generation state of the fuel cell , and a control method at the time of failure of the fuel cell system,
The controller is
When the failure determination unit determines that the drain valve has failed , control to increase the valve opening time of the purge valve from before the determination ,
Determining whether the power generation state has reached a state threshold for determining the power generation state of the fuel cell;
Control is performed so that the supply amount of the cathode gas supplied to the fuel cell is increased from that before the determination when the purge valve opening time is increased and the power generation state does not reach the state threshold. A control method in the event of a failure of a fuel cell system.

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