JP5201308B2 - Fuel cell system - Google Patents

Description

  The present invention provides a fuel cell system including a variable gas supply device that adjusts a gas state on the upstream side and supplies it to the downstream side in a supply channel for flowing fuel gas supplied from a fuel supply source to the fuel cell. About.

  Currently, a fuel cell system including a fuel cell that receives a supply of reaction gas (fuel gas and oxidizing gas) and generates electric power has been proposed and put into practical use. Such a fuel cell system is provided with a fuel supply channel for flowing fuel gas supplied from a fuel supply source such as a hydrogen tank to the fuel cell.

  By the way, when the supply pressure of the fuel gas from the fuel supply source is extremely high, a pressure regulating valve (regulator) for reducing the supply pressure to a certain value is generally provided in the fuel supply flow path. In the pressure regulating valve, it is difficult to quickly change the supply pressure of the fuel gas (that is, the response is low), and it is impossible to perform high-precision pressure regulation that changes the target pressure in multiple stages.

For this reason, a technique has been proposed in which an injector (variable gas supply device) that changes the supply pressure of fuel gas in multiple stages is provided in the fuel supply flow path (see, for example, Patent Document 1).
JP 2005-302563 A

  However, in the fuel cell system in which the injector described in Patent Document 1 is provided in the fuel supply flow path, the injector in the valve-open state is closed when, for example, a foreign object bites into the injector. However, there is a possibility that a valve opening abnormality that cannot be closed while the valve is open may occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a fuel cell system that can cancel a valve opening abnormality of a variable gas supply device during operation.

In order to achieve the above object, a fuel cell system according to the present invention includes a fuel cell, a supply channel for flowing a fuel gas supplied from a fuel supply source to the fuel cell, and an upstream side of the supply channel. of a variable gas supply device for supplying to the downstream side by adjusting the gas state, in the variable gas supply device comprising and a control unit for controlling driving the fuel cell system, the fuel off-gas discharged from the fuel cell A circulation passage for returning to the supply passage; and a discharge passage connected to the circulation passage through a discharge valve . It is an electromagnetically driven on-off valve that is driven at a driving cycle and is separated from the valve seat, and the control device detects a valve opening abnormality in which the variable gas supply device does not return from a valve opening state to a valve closing state during operation. Then, the variable gas supply device Respect, to repeat several times the opening and closing driving control consisting opening command and closing command, further, when the state in which the outlet pressure of the variable gas supply device exceeds a predetermined first threshold value continues for a predetermined time Is configured to reduce the outlet pressure by opening the discharge valve, and repeat the opening / closing drive control a plurality of times after the outlet pressure has decreased to a predetermined second threshold value that is smaller than the first threshold value. is there.

  According to this configuration, when a valve opening abnormality that cannot be closed while the valve is open due to, for example, foreign matter biting into the variable gas supply device, the control device performs open / close drive control on the variable gas supply device. As a result, the driving force in the opening direction and the driving force in the closing direction opposite to the driving force are repeatedly generated in the variable gas supply device. Therefore, for example, it is possible to alternately apply the force in the biting release direction and the force in the biting direction to the foreign matter caught in the variable gas supply device, and remove the foreign matter from the biting position.

In the fuel cell system of the present invention, in order to detect the valve opening abnormality of the variable gas supply device with higher accuracy and avoid unnecessary repetition of the opening / closing drive control, the control device supplies the variable gas supply at the earliest. after state outlet pressure of the device exceeds the first threshold continues for a predetermined time, and repeat several times the opening and closing drive control.

Here, when the variable gas supply device is abnormal in valve opening, the outlet pressure and the inlet pressure are the same, but when the inlet pressure exceeds a predetermined pressure, the valve body is opened and closed depending on the electromagnetic driving force. There is a risk that it will not be possible. Therefore, in the fuel cell system of the present invention, in order to ensure the opening / closing operation of the variable gas supply device, the control device has a predetermined value at which the outlet pressure of the variable gas supply device is smaller than the first threshold value. after lowered to the second threshold value, so that repeated a plurality of times the opening and closing drive control.

In order to reduce the outlet pressure to the second threshold, for example, a circulation channel for returning the fuel off-gas discharged from the fuel cell to the supply channel, and a connection to the circulation channel via a discharge valve a discharge passage which is, in the system configuration wherein the control device is so as to open the discharge valve.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which can cancel | release the valve opening abnormality of a variable gas supply apparatus during driving | operation can be provided.

  Hereinafter, a fuel cell system 1 according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an example in which the present invention is applied to an in-vehicle power generation system of a fuel cell vehicle (moving body) will be described, but the present invention is applied to various moving bodies (robots, ships, aircrafts, etc.) other than the fuel cell vehicle. The fuel cell system according to the invention can also be mounted. Further, the fuel cell system according to the present invention may be applied to a stationary power generation system used as a power generation facility for a building (house, building, etc.).

  First, the configuration of the fuel cell system 1 according to the embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the fuel cell system 1 according to the present embodiment includes a fuel cell 10 that generates electric power upon receiving a supply of reaction gas (oxidation gas and fuel gas), and the fuel cell 10 has an oxidant gas. An oxidizing gas piping system 2 for supplying the air, a hydrogen gas piping system 3 for supplying hydrogen gas as a fuel gas to the fuel cell 10, a control device 4 for integrated control of the entire system, and the like.

  The fuel cell 10 has a stack structure in which a required number of unit cells that receive a reaction gas and generate electric power through an electrochemical reaction are stacked. The electric power generated by the fuel cell 10 is supplied to a PCU (Power Control Unit) 11. The PCU 11 includes an inverter, a DC-DC converter, and the like that are disposed between the fuel cell 10 and the traction motor 12. Further, the fuel cell 10 is provided with a current sensor 13 for detecting a current during power generation.

  The oxidant gas piping system 2 includes an air supply passage 21 that supplies the oxidant gas (air) humidified by the humidifier 20 to the fuel cell 10, and an air exhaust that guides the oxidant off-gas discharged from the fuel cell 10 to the humidifier 20. A flow path 22 and an exhaust flow path 23 for guiding the oxidizing off gas from the humidifier 21 to the outside are provided. The air supply passage 21 is provided with a compressor 24 that takes in the oxidizing gas in the atmosphere and pumps it to the humidifier 20.

  The hydrogen gas piping system 3 includes a hydrogen tank 30 as a fuel supply source storing high-pressure (for example, 70 MPa) hydrogen gas, and hydrogen as a fuel supply passage for supplying the hydrogen gas from the hydrogen tank 30 to the fuel cell 10. A supply flow path 31 and a circulation flow path 32 for returning the hydrogen off-gas discharged from the fuel cell 10 to the hydrogen supply flow path 31 are provided.

  Instead of the hydrogen tank 30, a reformer that generates a hydrogen-rich reformed gas from a hydrocarbon-based fuel, a high-pressure gas tank that stores the reformed gas generated by the reformer in a high-pressure state, and Can also be employed as a fuel supply source. A tank having a hydrogen storage alloy may be employed as a fuel supply source.

  The hydrogen supply flow path 31 is provided with a shutoff valve 33 that shuts off or allows the supply of hydrogen gas from the hydrogen tank 30, a regulator 34 that adjusts the pressure of the hydrogen gas, and an injector 35. A primary pressure sensor 41 and a temperature sensor 42 that detect the pressure and temperature of the hydrogen gas in the hydrogen supply flow path 31 are provided on the upstream side of the injector 35.

  Further, on the downstream side of the injector 35 and upstream of the junction between the hydrogen supply flow path 31 and the circulation flow path 32, a secondary pressure sensor 43 that detects the pressure of the hydrogen gas in the hydrogen supply flow path 31. And the relief valve 44 opened when the inside of the hydrogen supply flow path 31 reaches a predetermined operating pressure is provided.

  The regulator 34 is a device that regulates the upstream pressure (primary pressure) to a preset secondary pressure. In the present embodiment, a mechanical pressure reducing valve that reduces the primary pressure is employed as the regulator 34. The mechanical pressure reducing valve has a structure in which a back pressure chamber and a pressure adjusting chamber are formed with a diaphragm therebetween, and the primary pressure is reduced to a predetermined pressure in the pressure adjusting chamber by the back pressure in the back pressure chamber. Thus, a publicly known configuration for the secondary pressure can be employed.

  The injector 35 is an electromagnetically driven on-off valve capable of adjusting the gas flow rate and gas pressure by driving the valve body directly with a predetermined driving cycle with an electromagnetic driving force and separating it from the valve seat. The injector 35 includes a valve seat having an injection hole for injecting gaseous fuel such as hydrogen gas, a nozzle body for supplying and guiding the gaseous fuel to the injection hole, and an axial direction (gas flow direction) with respect to the nozzle body. And a valve body that is movably accommodated and opens and closes the injection hole.

  In the present embodiment, the valve body of the injector 35 is driven by a solenoid which is an electromagnetic drive device, and the opening area of the injection hole is set in two stages, multiple stages or by turning on and off the pulsed excitation current supplied to the solenoid. It can be switched infinitely.

  Since the gas flow rate is adjusted by opening and closing the valve body of the injector 35 and the gas pressure supplied downstream of the injector 35 is reduced from the gas pressure upstream of the injector 35, the injector 35 is controlled by a pressure regulating valve (pressure reducing valve). , Regulator). Further, in the present embodiment, a variable pressure control valve capable of changing the pressure adjustment amount (pressure reduction amount) of the upstream gas pressure of the injector 35 so as to match the required pressure within a predetermined pressure range in accordance with the gas requirement. Can also be interpreted.

  As described above, the injector 35 adjusts the gas state (gas flow rate, hydrogen molar concentration, gas pressure) on the upstream side of the hydrogen supply flow path 31 and supplies it to the downstream side. The variable gas supply device according to the present invention. It corresponds to.

  In the present embodiment, as shown in FIG. 1, the injector 35 is disposed on the upstream side of the junction A <b> 1 between the hydrogen supply flow path 31 and the circulation flow path 32. Further, as shown by a broken line in FIG. 1, when a plurality of hydrogen tanks 30 are employed as the fuel supply source, the hydrogen gas supplied from each hydrogen tank 30 joins more than the part (hydrogen gas joining part A2). The injector 35 is arranged on the downstream side.

  A discharge flow path 38 is connected to the circulation flow path 32 via a gas-liquid separator 36 and an exhaust drain valve (discharge valve) 37. The gas-liquid separator 36 collects moisture from the hydrogen off gas. The exhaust / drain valve 37 operates according to a command from the control device 4 to discharge (purge) the moisture collected by the gas-liquid separator 36 and the hydrogen off-gas containing impurities in the circulation flow path 32 to the outside. Is.

  In addition, the circulation channel 32 is provided with a hydrogen pump 39 that pressurizes the hydrogen off gas in the circulation channel 32 and sends it to the hydrogen supply channel 31 side. The hydrogen off-gas discharged through the exhaust / drain valve 37 and the discharge passage 38 is diluted by the diluter 40 and merges with the oxidizing off-gas in the exhaust passage 23.

  The control device 4 detects an operation amount of an acceleration operation device (accelerator or the like) provided in the vehicle, receives control information such as an acceleration request value (for example, a required power generation amount from a load device such as the traction motor 12), Control the operation of various devices in the system.

  In addition to the traction motor 12, the load device is an auxiliary device (for example, a compressor 24, a hydrogen pump 39, a cooling pump motor, or the like) necessary for operating the fuel cell 10, and various types of vehicles involved in traveling of the vehicle. It is a collective term for power consumption devices including actuators used in devices (transmissions, wheel control devices, steering devices, suspension devices, etc.), occupant space air conditioners (air conditioners), lighting, audio, and the like.

  The control device 4 is configured by a computer system (not shown). Such a computer system includes a CPU, ROM, RAM, HDD, input / output interface, display, and the like, and various control operations are realized by the CPU reading and executing various control programs recorded in the ROM. It is like that.

  Specifically, as shown in FIG. 2, the control device 4 is consumed by the fuel cell 10 based on the operating state of the fuel cell 10 (current value during power generation of the fuel cell 10 detected by the current sensor 13). The amount of hydrogen gas (hereinafter referred to as “hydrogen consumption”) is calculated (fuel consumption calculation function: B1). In the present embodiment, the hydrogen consumption is calculated and updated for each calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the current value of the fuel cell 10 and the hydrogen consumption.

  Further, the control device 4 determines the target pressure value of the hydrogen gas (the fuel cell 10 at the downstream position of the injector 35) based on the operating state of the fuel cell 10 (the current value during power generation of the fuel cell 10 detected by the current sensor 13). Target gas supply pressure) (target pressure value calculation function: B2). In the present embodiment, a position (pressure) where the secondary pressure sensor 43 is arranged for each calculation cycle of the control device 4 using a specific map representing the relationship between the current value of the fuel cell 10 and the target pressure value. The target pressure value at the pressure adjustment position where adjustment is required is calculated and updated.

  Further, the control device 4 calculates the feedback correction flow rate based on the deviation between the calculated target pressure value and the detected pressure value at the downstream position (pressure adjustment position) of the injector 35 detected by the secondary pressure sensor 43. (Feedback correction flow rate calculation function: B3). The feedback correction flow rate is a hydrogen gas flow rate (pressure difference reduction correction flow rate) added to the hydrogen consumption in order to reduce the deviation between the target pressure value and the detected pressure value. In the present embodiment, the feedback correction flow rate is calculated and updated every calculation cycle of the control device 4 using a target tracking control law such as PI control.

  Moreover, the control apparatus 4 calculates the feedforward correction | amendment flow volume corresponding to the deviation of the target pressure value calculated last time and the target pressure value calculated this time (feedforward correction | amendment flow volume calculation function: B4). The feedforward correction flow rate is a change in the hydrogen gas flow rate due to the change in the target pressure value (correction flow corresponding to the pressure difference). In the present embodiment, the feedforward correction flow rate is calculated and updated every calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the deviation of the target pressure value and the feedforward correction flow rate. .

  Further, the control device 4 determines the static flow rate upstream of the injector 35 based on the gas state upstream of the injector 35 (hydrogen gas pressure detected by the primary pressure sensor 41 and hydrogen gas temperature detected by the temperature sensor 42). (Static flow rate calculation function: B5). In the present embodiment, the static flow rate is calculated for each calculation cycle of the control device 4 using a specific calculation formula representing the relationship between the pressure and temperature of the hydrogen gas upstream of the injector 35 and the static flow rate. We are going to update.

  Further, the control device 4 calculates the invalid injection time of the injector 35 based on the gas state upstream of the injector 35 (pressure and temperature of hydrogen gas) and the applied voltage (invalid injection time calculation function: B6). Here, the invalid injection time means the time required from when the injector 35 receives a control signal from the control device 4 until the actual injection is started. In the present embodiment, the invalid injection time is calculated for each calculation cycle of the control device 4 using a specific map representing the relationship between the pressure and temperature of the hydrogen gas upstream of the injector 35, the applied voltage, and the invalid injection time. I am going to update it.

  Further, the control device 4 calculates the injection flow rate of the injector 35 by adding the hydrogen consumption amount, the feedback correction flow rate, and the feedforward correction flow rate (injection flow rate calculation function: B7). Then, the control device 4 calculates the basic injection time of the injector 35 by multiplying the value obtained by dividing the injection flow rate of the injector 35 by the static flow rate by the drive cycle of the injector 35, and the basic injection time and the invalid injection time. Are added to calculate the total injection time of the injector 35 (total injection time calculation function: B8).

  Here, the drive cycle means a stepped (on / off) waveform cycle representing the open / close state of the injection hole of the injector 35. In the present embodiment, the drive period is set to a constant value by the control device 4.

  And the control apparatus 4 controls the gas injection time and gas injection timing of the injector 35 by outputting the control signal for implement | achieving the total injection time of the injector 35 computed through the above procedure, and fuel cell The flow rate and pressure of the hydrogen gas supplied to 10 are adjusted.

  Next, the valve opening abnormality canceling control of the fuel cell system 1 will be described using the time chart of FIG.

  During normal operation of the fuel cell system 1, hydrogen gas is supplied from the hydrogen tank 30 to the fuel electrode of the fuel cell 10 through the hydrogen supply channel 31, and the air that has been subjected to humidification adjustment passes through the air supply channel 21. Then, power is generated by being supplied to the oxidation electrode of the fuel cell 10. At this time, the power (required power) to be drawn from the fuel cell 10 is calculated by the control device 4, and hydrogen gas and air in an amount corresponding to the amount of power generation are supplied into the fuel cell 10.

  Specifically, first, in the time chart of FIG. 3, (a) shows the normal and abnormal states of the injector 35, (b) shows the outlet pressure of the injector 35 detected by the secondary pressure sensor 43, ( (c) is a command value of the outlet pressure to the injector 35 of the control device 4, (d) is a drive permission status of the injector 35 by normal control which is not valve opening abnormality cancellation control by the control device 4, and (e) is a control device. (F) is an opening / closing command to the exhaust / drain valve 37 by the control device 4, and (g) is a minimum oxidation off gas in the diluter 40 controlled by driving the compressor 24 by the control device 4. (H) is a retry counter for valve opening abnormality release control stored in the control device 4, and (i) is an injector 3 stored in the control device 4. Shows the outlet pressure of the rising abnormality that is open abnormality occurs and the injector outlet pressure rises abnormality flag indicating that each.

  The control device 4 performs the normal control until the valve opening abnormality occurs in the injector 35 (time t4) and the valve opening abnormality release control is started (time t6). That is, until the time point t6, the command value of the outlet pressure to the injector 35 of the control device 4 shown in FIG. 3C is constant for convenience in FIG. It is calculated by the calculation function B2.

  Further, until time t6, the drive permission of the injector 35 by the normal control shown in FIG. 3D is ON, and the drive control of the injector 35 by the normal control can be performed. For this reason, the control device 4 turns ON the valve opening command to the injector 35 by the normal control shown in FIG. 3E (at time t1), and after the total injection time calculated by the total injection time calculation function B8 has elapsed, the valve opening command Is turned off (at time t2), the outlet pressure of the injector 35 detected by the secondary pressure sensor 43 shown in FIG.

  Further, until the time t6, the minimum oxidizing off-gas amount in the diluter 40 controlled by the driving of the compressor 24 by the control device 4 shown in FIG. 3 (g) is constant for convenience in FIG. The driving of the compressor 24 is controlled by a map in accordance with the amount of hydrogen gas supplied to the fuel electrode of the battery 10, and the amount is controlled accordingly.

  Furthermore, the exhaust / drain valve 37 is opened at an appropriate purge timing. In FIG. 3F, for convenience, the exhaust drain valve 37 is closed for a predetermined time before the time point t6 when the valve opening abnormality release control is started. It is assumed that the state was maintained.

  Then, as shown in FIG. 3E, the control device 4 controls the opening of the injector 35 by normal control, in other words, turns on the valve opening command to the injector 35 (at time t3), and in other words, supplies the solenoid to the solenoid. The total injection time calculated by the above-described total injection time calculation function B8 is issued by issuing a command to energize the solenoid with a valve-opening holding current that can maintain the valve-opened state separated from the valve seat by the electromagnetic driving force obtained by energization. After the lapse of time, the valve closing control of the injector 35, in other words, when the valve opening command to the injector 35 is turned off (at time t4), in other words, depending on the command or electromagnetic driving force for shutting off the energization to the solenoid, When a command to energize the solenoid with a current that cannot maintain the state of being separated from the valve seat is issued to the injector 35, If a valve opening abnormality that cannot be closed even if the injector 35 in the valve open state is controlled to be closed even if the injector 35 is in the valve open state is generated, the valve is closed in spite of the valve closing control. The outlet pressure of the injector 35 detected by the secondary pressure sensor 43 shown in FIG.

  At this time, the control device 4 monitors the outlet pressure of the injector 35. When the valve 35 is abnormally opened in the injector 35, the outlet pressure detected by the secondary side pressure sensor 43 cannot be generated in a normal state. When the degassing start threshold value (first threshold value) X1 is exceeded (at time t5), the following valve opening abnormality canceling control is performed after a predetermined degassing start waiting time T1 elapses (time t6).

  That is, when the predetermined degassing start waiting time T1 elapses from the time when the detected pressure of the secondary side pressure sensor 43 exceeds the predetermined degassing start threshold X1 (time t5) (time t6), the control device 4 The command value of the outlet pressure to the injector 35 shown in 3 (c) is not calculated by the target pressure value calculation function B2, but is raised to a predetermined constant value higher than the value calculated by the target pressure value calculation function B2.

  At the same time (at time t6), the control device 4 turns off the drive permission of the injector 35 by the normal control shown in FIG. 3D, and restricts the drive control of the injector 35 by the normal control. At time t6), in order to lower the outlet pressure detected by the secondary side pressure sensor 43, the exhaust / drain valve 37 is opened as shown in FIG.

  At the same time (at time t6), in order to reduce the concentration of hydrogen gas discharged from the exhaust / drain valve 37 to a predetermined value or less, the control device 4 controls the drive of the compressor 24 to reduce the minimum oxidizing off-gas amount in the diluter 40 to the hydrogen As shown in FIG. 3 (g), the gas concentration is increased as shown in FIG.

  As described above, the outlet pressure of the injector 35 detected by the secondary pressure sensor 43 shown in FIG. 3B decreases from the time point t6 when the exhaust / drain valve 37 is opened. When the outlet pressure of the injector 35 falls to a predetermined retry start threshold (second threshold) X2 that falls within the normal range during normal operation (at time t7), the control device 4 passes a predetermined retry start waiting time T2. (Time t8), the opening / closing drive control for the first injector 35 for releasing the valve opening abnormality shown in FIG. Repeat only once.

  That is, the valve opening command is turned ON to control the opening of the injector 35 (at time t8), and then the valve opening command is turned OFF to control the closing of the injector 35 (time t9). The valve command is turned on (at time t10), the valve opening command to the injector 35 is subsequently turned off (time t11), the valve opening command to the injector 35 is turned on again (time t12), and the valve 35 is opened to the injector 35. The valve command is turned OFF (time t13).

  Here, in the opening / closing drive control for releasing the valve opening abnormality, the injector 35 is ON / OFF controlled with the minimum drive cycle. FIG. 3 shows a case where the valve opening abnormality is canceled by the valve closing control after the third valve opening control of the injector 35 in the first opening / closing drive control for releasing the valve opening abnormality. When the valve opening command to the first injector 35 is turned ON (at time t8) and the outlet pressure of the injector 35 detected by the secondary pressure sensor 43 is increased, the valve opening command is turned OFF (time t9). The reason why the outlet pressure of the injector 35 subsequently decreases despite the fact that the valve opening abnormality has not been released is that the exhaust / drain valve 37 is open. Similarly, the outlet pressure of the injector 35 decreases after the valve opening command to the second and third injectors 35 is turned ON and OFF.

  Then, after the first opening / closing drive control end time (time t14) for releasing the valve opening abnormality, the control device 4 once returns to the normal control. That is, the command value of the outlet pressure to the injector 35 of the control device 4 shown in FIG. 3C is constant for convenience in FIG. 3C, but is actually calculated by the target pressure value calculation function B2 described above. Moreover, the drive permission of the injector 35 by the normal control shown in FIG. 3D is turned on, and the drive control of the injector 35 by the normal control can be performed.

  The exhaust / drain valve 37 is opened at an appropriate purge timing. In FIG. 3 (f), for convenience, the valve closing state is maintained for a predetermined time after the time point t14. Further, after the time point t14, the minimum oxidizing off-gas amount in the diluter 40 controlled by the driving of the compressor 24 by the control device 4 shown in FIG. 3 (g) is constant for convenience in FIG. The driving of the compressor 24 is controlled by a map according to the amount of hydrogen gas supplied to the 10 fuel electrodes, and the amount is accordingly.

  Then, the control device 4 turns ON the valve opening command shown in FIG. 3E to the injector 35 by the normal control (at time t14), and issues the valve opening command after the total injection time calculated by the total injection time calculation function B8 described above. When turned OFF (at time t15), the valve opening abnormality of the injector 35 is canceled by the first opening / closing drive control as described above. Accordingly, the secondary side pressure sensor 43 shown in FIG. The detected outlet pressure of the injector 35 rises normally after it rises despite the exhaust drain valve 37 being closed.

  At the end of the first opening / closing drive control for releasing the valve opening abnormality (at time t14), the control device 4 changes the retry counter for the valve opening abnormality releasing control shown in FIG. .

  Here, in FIG. 3, the case where the valve opening abnormality is canceled by the first opening / closing drive control performed when the valve opening abnormality occurs is described as an example, but the first time when the valve opening abnormality occurs is performed. If the valve opening abnormality is not canceled by the opening / closing drive control, the outlet pressure detected by the secondary side pressure sensor 43 again exceeds the predetermined degassing start threshold value X1 similarly to the time point t5. When the outlet pressure detected by the secondary pressure sensor 43 exceeds the degassing start threshold value X1, the control device 4 performs the opening / closing drive control from the time t5 to the time t14 a predetermined number of times, specifically three times thereafter ( Repeat a total of 4 times) until the valve opening abnormality is cleared.

  At that time, at the end of the second opening / closing drive control for releasing the valve opening abnormality (time t16), the retry counter for the valve opening abnormality releasing control shown in FIG. In addition, at the end of the third opening / closing drive control (time t17) for canceling the valve opening abnormality, the retry counter for the valve opening abnormality canceling control shown in FIG. Further, at the end of the fourth opening / closing drive control for releasing the valve opening abnormality (at time t18), the retry counter for the valve opening abnormality releasing control shown in FIG. Will be.

  Here, the control device 4 determines that the valve opening abnormality cannot be canceled when the opening / closing drive control for releasing the valve opening abnormality is performed four times as the predetermined number of retries and the retry counter becomes 4 (at time t18). Then, the valve opening abnormal stop control of the injector 35 is performed.

  Hereinafter, the valve opening abnormal stop control will be described with reference to the time chart of FIG. In FIG. 4, the same parts as those in the time chart of FIG.

  In the time chart of FIG. 4, (j) is an opening / closing command to the shutoff valve 33 by the control device 4, (k) is an inlet pressure of the injector 35 detected by the primary side pressure sensor 42, and (l) is a fuel cell. The operation states of the system 1 are shown respectively. Until the valve opening abnormality cannot be canceled and the abnormal state continues and valve opening abnormality stop control is started (t21 to t26), the control device 4 performs the normal control similar to the above (t1 to t26 in FIG. 3). )I do.

  And the control apparatus 4 does not cancel the valve opening abnormality of the injector 35 based on the outlet pressure of the injector 35, the abnormal state continues, and the outlet pressure detected by the secondary side pressure sensor 43 is normal. When a predetermined degassing start threshold value X1 that cannot sometimes occur is exceeded (at time t25), after a predetermined degassing start waiting time T1 elapses (time t26), the outlet of the injector 35 shown in FIG. An injector outlet pressure increase abnormality flag indicating a pressure increase abnormality, that is, a valve opening abnormality is turned ON, and the following valve opening abnormality stop control is performed.

  That is, when the predetermined degassing start waiting time T1 elapses from the time when the detected pressure of the secondary side pressure sensor 43 exceeds the predetermined degassing start threshold X1 (time t25) (time t26), the control device 4 By turning OFF the outlet pressure command to the injector 35 shown in FIG. 4C, the drive of the injector 35 is turned OFF as shown in FIG.

  At the same time (at time t26), as shown in FIG. 4 (j), in order to stop the supply of the hydrogen gas from the hydrogen tank 30, the shutoff valve 33, which is the main stop valve of the hydrogen tank 30, is closed to supply the hydrogen gas. In order to reduce the outlet pressure detected by the secondary pressure sensor 43, the exhaust / drain valve 37 is opened as shown in FIG.

  At the same time (at time t26), in order to lower the concentration of hydrogen gas discharged from the exhaust / drain valve 37 to a predetermined value or less, the control device 4 controls the drive of the compressor 24 to reduce the minimum oxidizing off-gas amount in the diluter 40 to the hydrogen The gas concentration is increased as shown in FIG. 4 (g) so as to ensure an amount that can be diluted below a predetermined value.

  As described above, the outlet pressure of the injector 35 detected by the secondary pressure sensor 43 shown in FIG. 4B from the time t26 when the shut-off valve 33 is closed and the exhaust / drain valve 37 is opened. In addition, the inlet pressure of the injector 35 detected by the primary pressure sensor 42 shown in FIG. 4 (k) decreases, and the value of the inlet pressure of the injector 35 is lower than the operating pressure of the relief valve 44. When the pressure falls to X3 (at time t27), the control device 4 waits for a predetermined non-relief pressure drop time T3 to elapse (at time t28). ).

  Thereafter, when the value of the outlet pressure of the injector 35 falls to a predetermined stop processing start threshold value X4 that is sufficiently lower than the operating pressure of the relief valve 44 within the normal range of the outlet pressure of the injector 35 during normal operation (at time t29). Then, it waits for a predetermined stop start waiting time T4 to elapse (at time t30).

  At the same time (at time t30), the control device 4 turns off the system as shown in FIG. 4 (l), thereby turning off the drive permission of the injector 35 as shown in FIG. 4 (d). As shown in (f), the exhaust / drain valve 37 is closed, and as shown in FIG. 4 (g), the drive of the compressor 24 is stopped, and the minimum oxidizing off-gas amount in the diluter 40 is set to 0 to operate the fuel cell 10. Stop completely.

  In the fuel cell system 1 that has been stopped as described above, since the injector outlet pressure increase abnormality flag is ON, the injector outlet pressure increase abnormality flag is turned ON from the control device 4 after maintenance. By reading whether or not, it is possible to confirm the cause history that the fuel cell system 1 has stopped due to the occurrence of valve opening abnormality, and it is possible to immediately take action to replace or repair the injector 35.

  According to the fuel cell system 1 according to the embodiment described above, the control device 4 detects this when a valve opening abnormality that cannot be closed while the valve is open due to, for example, foreign matter biting into the injector 35. Thus, the opening / closing drive control for the injector 35 is repeated a plurality of times, whereby the valve body of the injector 35 is repeatedly applied with an opening direction driving force and a closing direction driving force opposite to the same direction. Will occur.

  Therefore, it is possible to alternately apply a force in the biting release direction and a force in the biting direction to the foreign matter and the like bitten by the valve body of the injector 35 and remove the foreign matter from the biting position. Therefore, the valve opening abnormality of the injector 35 can be canceled during operation.

  In the above embodiment, an example in which the exhaust drain valve 37 that realizes both exhaust and drainage is provided in the circulation flow path 32 is shown. However, the moisture recovered by the gas-liquid separator 36 is discharged to the outside. A drain valve and an exhaust valve for discharging the gas in the circulation flow path 32 to the outside can be provided separately, and the exhaust valve can be controlled by the control device 4.

1 is a configuration diagram of a fuel cell system according to an embodiment of the present invention. It is a control block diagram for demonstrating the control aspect of the control apparatus of the fuel cell system shown in FIG. 3 is a time chart for explaining valve opening abnormality canceling control of the fuel cell system shown in FIG. 1. 3 is a time chart for explaining valve opening abnormal stop control in the fuel cell system shown in FIG. 1.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 3 ... Hydrogen gas piping system (fuel supply system), 4 ... Control apparatus (control means), 10 ... Fuel cell, 30 ... Hydrogen tank (fuel supply source), 31 ... Hydrogen supply flow path (fuel) (Supply flow path), 32 ... circulation flow path, 35 ... injector (variable gas supply device, on-off valve), 37 ... exhaust drain valve (discharge valve), 38 ... discharge flow path, 43 ... secondary pressure sensor, X1 ... Degassing start threshold (first threshold), X2... Retry start threshold (second threshold).

Claims (1)

A fuel cell, a supply channel for flowing fuel gas supplied from a fuel supply source to the fuel cell, and a variable gas supply device that adjusts the gas state upstream of the supply channel and supplies the gas downstream And a fuel cell system comprising a control device for driving and controlling the variable gas supply device,
A circulation flow path for returning the fuel off-gas discharged from the fuel cell to the supply flow path, and a discharge flow path connected to the circulation flow path via a discharge valve,
The variable gas supply device is an electromagnetically driven on / off valve that drives the valve body at a predetermined driving cycle by an electromagnetic driving force to separate the valve body from the valve seat,
When the valve opening abnormality in which the variable gas supply device does not return from the valve opening state to the valve closing state is detected during operation, the control device performs a valve opening command and a valve closing command to the variable gas supply device. the opening and closing control made to repeat a plurality of times, further, when the state where the outlet pressure of the variable gas supply device exceeds a predetermined first threshold value continues for a predetermined time, said by opening the discharge valve A fuel cell system in which the opening / closing drive control is repeated a plurality of times after the outlet pressure is reduced and the outlet pressure is reduced to a predetermined second threshold value smaller than the first threshold value .

Images