JP2016134348A - Fuel battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel battery system that can control a fuel battery according to a condition matched with the degree of puddle.SOLUTION: In a fuel battery system for controlling the flow rate and pressure of cathode gas based on a request output required to a fuel battery 10, and an output flow rate characteristic and an output pressure characteristic that represent the relationship between the output of the fuel battery determined every temperature of cooing water flowing in the fuel battery and the flow rate and pressure of cathode gas, when an actual measurement value of the valve opening of a back pressure adjusting valve 72 for adjusting the pressure of the cathode gas on the basis of a pressure sensor 68P in a cathode gas flow path is larger, by a predetermined value, than a reference valve opening which is specified on the basis of a reference valve opening characteristic for setting the reference valve opening of the back pressure adjusting valve for the flow rate and pressure of the cathode gas stored every temperature of cooling water in a storage unit 22, and the actual measurement values of the temperature of the cooling water and the flow rate and pressure of the cathode gas, the output pressure characteristic is changed so that the pressure to a predetermined output is lowered. When the actual measurement value is smaller by the predetermined value, the output pressure characteristic is changed so that the pressure to the predetermined output is increased.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  A fuel cell that generates electricity by an electrochemical reaction between an anode gas and a cathode gas has attracted attention as an energy source. In a fuel cell system equipped with such a fuel cell, the flow rate of the cathode gas supplied to the cathode is controlled to a target flow rate corresponding to the required power generation amount in accordance with the change in the power generation amount of the fuel cell. It is known to control pressure. In addition, as a method for controlling the pressure of the cathode gas, the pressure of the cathode gas is determined based on the output-pressure characteristic that defines the relationship between the output of the fuel cell and the pressure of the cathode gas and the required output required for the fuel cell. There is known a method for controlling the above (for example, see Patent Document 1). In addition, since water may accumulate in the fuel cell depending on the operating state of the fuel cell, a method for performing appropriate power generation control when water is accumulated in the fuel cell is known (for example, patents). Reference 2).

JP 2014-82115 A JP 2011-90886 A

  As in Patent Document 1, the cathode gas pressure control using a predetermined output-pressure characteristic (operating point MAP) may not be a control corresponding to the actual state of the fuel cell. This is because the amount of water accumulated in the fuel cell changes depending on the operating state of the fuel cell. For example, when the fuel cell system is mounted on a fuel cell vehicle or the like, depending on the actual vehicle driving conditions (for example, how the driver operates (how to press the accelerator pedal, etc.)) This is because of changes.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fuel cell system capable of controlling the fuel cell according to conditions according to the amount of water in the fuel cell.

  The present invention relates to a required output required for a fuel cell, a relationship between an output of the fuel cell and a flow rate of cathode gas supplied to the fuel cell, which is determined for each temperature of cooling water flowing through the fuel cell, and In the fuel cell system that controls the flow rate and pressure of the cathode gas based on the relationship between the output of the fuel cell and the pressure of the cathode gas, the fuel cell system is provided in a supply path of the cathode gas supplied to the fuel cell. A back pressure adjusting valve for adjusting the pressure of the cathode gas, and a reference valve opening degree of the back pressure adjusting valve with respect to the flow rate and pressure of the cathode gas for each temperature of the cooling water based on the pressure sensor. A storage unit that stores a reference valve opening characteristic; an acquisition unit that acquires an actual measurement value of the cooling water temperature, the cathode gas flow rate, the cathode gas pressure, and the valve opening of the back pressure regulating valve; Using the temperature of the cooling water acquired by the acquisition unit, the flow rate of the cathode gas, and the pressure of the cathode gas, and the reference valve opening characteristic stored in the storage unit, the back pressure adjustment valve When the valve opening of the back pressure regulating valve acquired by the acquiring unit is greater than a predetermined value with respect to the reference valve opening specified by the specifying unit, The change between the output of the fuel cell and the pressure of the cathode gas is performed to lower the pressure with respect to a predetermined output, and the valve opening degree of the back pressure regulating valve acquired by the acquiring unit is specified by the specifying unit. A change unit that changes the relationship between the output of the fuel cell and the pressure of the cathode gas to increase the pressure with respect to a predetermined output when the reference valve opening is smaller than a predetermined value. It is a battery system.

  According to the present invention, it is possible to control the fuel cell according to conditions according to the amount of water accumulated in the fuel cell, and efficient power generation becomes possible.

FIG. 1 is a diagram illustrating a schematic configuration of a fuel cell system according to a first embodiment. FIG. 2 is a flowchart illustrating an example of output-pressure characteristic change processing. FIG. 3 is a diagram illustrating a reference valve opening characteristic of the back pressure valve. FIG. 4 is a flowchart showing an example of output-pressure characteristic changing processing.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of a fuel cell system 100 according to the first embodiment. The fuel cell system 100 is mounted on, for example, a fuel cell vehicle or an electric vehicle as a system for supplying driving power. In the fuel cell system 100, the fuel cell 10 is a fuel that generates electric power by an electrochemical reaction between a fuel gas (anode gas, for example, hydrogen) supplied to the anode and an oxidant gas (cathode gas, for example, oxygen) supplied to the cathode. A stacked body in which a plurality of battery cells are stacked.

  Hydrogen as fuel gas is supplied to the anode of the fuel cell 10 from the hydrogen tank 42 storing high-pressure hydrogen via the anode gas supply flow path 40. The anode gas supply channel 40 is, for example, a pipe (pipe). Instead of the hydrogen tank 42, a hydrogen generator that generates hydrogen by a reforming reaction using, for example, alcohol, hydrocarbon, aldehyde or the like as a raw material may be used.

  The pressure and supply amount of the high-pressure hydrogen stored in the hydrogen tank 42 are adjusted by a shut valve 44 provided at the outlet of the hydrogen tank 42 and a regulator 46 and an injector 48 disposed in the anode gas supply channel 40. It is supplied to the anode of the fuel cell 10. The anode gas supply channel 40 is provided with a pressure sensor 40P for detecting the pressure in the anode gas supply channel 40.

  Exhaust gas from the anode (hereinafter referred to as anode off gas) is discharged to the anode gas discharge channel 50. The anode gas discharge channel 50 is a pipe (pipe), for example. The anode off-gas containing unconsumed hydrogen generated by power generation discharged to the anode gas discharge channel 50 can be recirculated to the anode gas supply channel 40 via the circulation channel 52. The circulation channel 52 is a pipe (pipe), for example. Note that the pressure of the anode off gas is relatively low as a result of the consumption of hydrogen by power generation in the fuel cell 10. For this reason, the circulation flow path 52 is provided with a circulation pump 54 for pressurizing the anode off gas when the anode off gas is recirculated. The circulation pump 54 is provided with a flow rate sensor 54F for detecting the circulation flow rate of the anode off gas.

  A flow path 56 (for example, a pipe) is branched and connected to the anode gas discharge flow path 50. A purge valve 58 is disposed in the flow path 56. While the purge valve 58 is closed, the anode off gas containing hydrogen that has not been consumed by power generation is supplied to the fuel cell 10 again via the circulation channel 52. Thereby, hydrogen can be used effectively.

  During the recirculation of the anode off gas, hydrogen is consumed by power generation, while impurities other than hydrogen (for example, nitrogen permeated from the cathode side to the anode side) remain without being consumed. For this reason, the impurity concentration in the anode off gas gradually increases. At this time, when the purge valve 58 is opened, the anode off-gas is discharged to the outside of the fuel cell system 100 together with the cathode off-gas to be described later via the flow paths 56 and 76. Thereby, the impurity concentration in the anode off gas can be reduced.

  The cathode of the fuel cell 10 is supplied with compressed air as an oxidant gas containing oxygen. Air is sucked from the air cleaner 60, compressed by the air compressor 62, and introduced into the humidifier 66 via the flow path 64 (for example, a pipe (pipe)). The compressed air introduced into the humidifier 66 is humidified by the humidifier 66 and then supplied from the cathode gas supply channel 68 to the cathode of the fuel cell 10. The air compressor 62 is provided with a flow rate sensor 62F for detecting the supply flow rate of air. The cathode gas supply channel 68 is provided with a pressure sensor 68P for detecting the pressure in the cathode gas supply channel 68. In addition, the structure in which the humidification apparatus 66 is not provided may be sufficient.

  Exhaust gas from the cathode (hereinafter referred to as “cathode off gas”) is discharged to a cathode gas discharge channel 70 (for example, a pipe). A back pressure adjusting valve 72 for adjusting the pressure of the cathode off gas is disposed in the cathode gas discharge channel 70. The high-humidity cathode off-gas discharged from the fuel cell 10 to the cathode gas discharge channel 70 is introduced into the humidifier 66 and used for humidifying the air, and then the channels 74 and 76 (for example, pipes) are used. And discharged to the outside of the fuel cell system 100.

  The fuel cell 10 generates heat by the above-described electrochemical reaction. For this reason, in order to make the temperature of the fuel cell 10 suitable for power generation, the fuel cell 10 is supplied with cooling water. The cooling water flows through a water channel 82 (for example, a pipe (pipe)) by a water pump 80, is cooled by a radiator 84, and is supplied to the fuel cell 10. A bypass water channel 86 (for example, a pipe (pipe)) for circulating the cooling water without passing through the radiator 84 is connected to the water channel 82. A rotary valve 88 is disposed at one connecting portion between the water channel 82 and the bypass water channel 86. By switching the rotary valve 88, the cooling water can be circulated through the water passage 82 and the bypass water passage 86 without passing through the radiator 84. A temperature sensor 90 for detecting the temperature of the cooling water discharged from the fuel cell 10 is provided in the water channel 82 at the discharge portion where the cooling water is discharged from the fuel cell 10. A temperature sensor 92 for detecting the temperature of the cooling water supplied to the fuel cell 10 is provided in the water channel 82 of the supply portion where the cooling water is supplied to the fuel cell 10.

  A cell monitor 32 is connected to the fuel cell 10. The cell monitor 32 detects cell voltage, current, impedance, etc. for each fuel cell in the fuel cell 10.

  The operation of the fuel cell system 100 is controlled by the control device 20. The control device 20 includes a microcomputer that includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and the like. The control device 20 controls the operation of the system according to a program stored in the storage unit 22 (for example, ROM). In addition to the above programs, the storage unit 22 also stores various maps used for controlling the fuel cell system 100. For example, the storage unit 22 stores, for each cooling water temperature, output-flow rate characteristics and output-pressure characteristics indicating the relationship between the output of the fuel cell 10 and the flow rate and pressure of the cathode gas supplied to the fuel cell 10. Has been. The storage unit 22 stores a reference valve opening characteristic that determines the reference valve opening of the back pressure adjusting valve 72 with respect to the flow rate and pressure of the cathode gas for each temperature of the cooling water. Details of the reference valve opening characteristic will be described later.

  The control device 20 includes, for example, various valves including the back pressure adjustment valve 72, a circulation pump 54, a water pump 80, an air compressor 62, and the like based on required outputs required for the fuel cell 10 and outputs of various sensors. The operation of the fuel cell system 100 including the process of driving and changing the output-pressure characteristics stored in the storage unit 22 is controlled.

  The control device 20 functions as the acquisition unit 24, the specification unit 26, the determination unit 28, and the change unit 30 in the process of changing the output-pressure characteristics. The acquisition unit 24 acquires the temperature of the cooling water, the flow rate of the cathode gas, the pressure of the cathode gas, and the valve opening degree of the back pressure adjustment valve 72. The specifying unit 26 uses the temperature of the cooling water acquired by the acquiring unit 24, the flow rate of the cathode gas, the pressure of the cathode gas, and the reference valve opening characteristic stored in the storage unit 22, to determine the back pressure adjustment valve. 72 reference valve openings are identified. The determination unit 28 determines the difference between the valve opening degree of the back pressure adjustment valve 72 acquired by the acquisition unit 24 and the reference valve opening degree specified by the specifying unit 26. The changing unit 30 changes the output-pressure characteristic stored in the storage unit 22 according to the result of the determination unit 28.

  FIG. 2 is a flowchart illustrating an example of a change process of the output-pressure characteristic stored in the storage unit 22. In FIG. 2, it is assumed that the flow rate and pressure of the cathode gas are controlled to the flow rate and pressure corresponding to the required output required for the fuel cell 10. That is, the control device 20 sets the required output based on the required output required for the fuel cell 10 and the output-flow rate characteristic, output-pressure characteristic, and reference valve opening characteristic stored in the storage unit 22. The flow rate and pressure of the corresponding cathode gas and the reference valve opening degree of the back pressure adjustment valve 72 are specified. Then, the control device 20 uses the air compressor 62 to control the flow rate of the cathode gas to a flow rate corresponding to the required output, and then sets the valve opening degree of the back pressure adjustment valve 72 to the reference valve opening degree. It is assumed that the valve opening of the back pressure adjusting valve 72 is adjusted based on the sensor 68P, and the cathode gas pressure is controlled to a pressure corresponding to the required output.

  As shown in FIG. 2, in step S10, the controller 20 measures the temperature of the cooling water, the flow rate of the cathode gas, the pressure of the cathode gas, and the pressure measured using the temperature sensor 90, the flow rate sensor 62F, the pressure sensor 68P, and the like. An actual measurement value of the valve opening degree of the back pressure adjusting valve 72 is acquired.

  After step S10, the process proceeds to step S12, and the control device 20 obtains the obtained cooling water temperature, the cathode gas flow rate, the cathode gas pressure, and the reference valve opening characteristic stored in the storage unit 22. And the reference valve opening degree S0 of the back pressure regulating valve 72 is specified.

  Here, a method for specifying the reference valve opening degree S0 of the back pressure adjusting valve 72 will be described. FIG. 3 is a diagram illustrating the reference valve opening characteristic of the back pressure adjustment valve 72 stored in the storage unit 22. As shown in FIG. 3, the reference valve opening characteristic is a back pressure with the cathode gas pressure and the cathode gas flow rate as axes at each cooling water temperature T (T = T1, T2, T3,...). The characteristic of the reference valve opening degree of the regulating valve 72 is shown (a specific line is not shown in FIG. 3), and one reference valve opening degree S0 for a specific pressure P1 and flow rate F1 of the cathode gas. Has come to be determined. Therefore, the control device 20 uses the reference valve opening characteristic stored in the storage unit 22 by using the temperature of the cooling water, the flow rate of the cathode gas, and the pressure of the cathode gas acquired in step S10, and the reference valve opening characteristic. The opening degree S0 can be specified.

  In step S14, the control device 20 determines whether or not the difference between the valve opening S1 of the back pressure regulating valve 72 acquired in step S10 and the reference valve opening S0 specified in step S12 is larger than a predetermined value α. To do. That is, the control device 20 determines whether or not | valve opening S1−reference valve opening S0 |> α is satisfied. The reason for making such a determination will be described next.

  As described above, the control device 20 determines the flow rate and pressure of the cathode gas based on the required output required for the fuel cell 10 and the output-flow rate characteristics and output-pressure characteristics stored in the storage unit 22. 62 and the back pressure regulating valve 72 are used for control. Here, when the fuel cell 10 is operated, water is generated in the fuel cell 10 (for example, in the cathode gas flow path). The amount of water accumulated in the fuel cell 10 depends on the operation status of the fuel cell 10 (for example, when the fuel cell system 100 is mounted on a fuel cell vehicle or the like, how the driver operates (for example, how to depress the accelerator pedal)). It depends on. Further, the pressure loss of the cathode gas flowing in the fuel cell 10 varies depending on the amount of water accumulated in the fuel cell 10. As water accumulates in the fuel cell 10, the pressure loss of the cathode gas increases.

  As described above, the control for setting the pressure of the cathode gas to the pressure corresponding to the required output required for the fuel cell 10 is performed by using the reference valve opening characteristic stored in the storage unit 22 as the valve opening of the back pressure regulating valve 72. Is performed by adjusting the valve opening degree of the back pressure adjusting valve 72 based on the pressure sensor 68P. In a state where the valve opening degree of the back pressure adjusting valve 72 is set to the reference valve opening degree, the pressure is detected by the pressure sensor 68P as the pressure loss of the cathode gas increases as the water is accumulated in the fuel cell 10. Is done. For this reason, the control device 20 performs control to increase the valve opening degree of the back pressure adjustment valve 72 in order to set the pressure at the pressure sensor 68P to a pressure corresponding to the required output required for the fuel cell 10. On the other hand, when the amount of water accumulated in the fuel cell 10 is small, the pressure is detected by the pressure sensor 68P so that the pressure at the pressure sensor 68P is required for the fuel cell 10. In order to obtain a pressure corresponding to the required output, control is performed to reduce the valve opening of the back pressure adjustment valve 72. For this reason, it is possible to estimate the amount of water accumulated in the fuel cell 10 by performing the determination in step S14, and determine whether the amount of water generated in the fuel cell 10 is within an allowable range. can do.

  When the difference between the valve opening S1 of the back pressure adjusting valve 72 and the reference valve opening S0 is equal to or smaller than the predetermined value α (No in step S14), the process proceeds to step S16. In step S <b> 16, the control device 20 does not change the output-pressure characteristic stored in the storage unit 22 because the amount of water in the fuel cell 10 is estimated to be within the allowable range.

  On the other hand, when the difference between the valve opening degree S1 of the back pressure regulating valve 72 and the reference valve opening degree S0 is larger than the predetermined value α (Yes in step S14), the process proceeds to step S18. In step S18, the control device 20 determines whether or not the difference between the valve opening S1 of the back pressure adjusting valve 72 and the reference valve opening S0 continues to be larger than the predetermined value α. This is not caused by the water generated in the fuel cell 10, but the difference between the valve opening of the back pressure regulating valve 72 and the reference valve opening is larger than a predetermined value due to some other accidental factor. The case is excluded.

  When the difference between the valve opening degree S1 of the back pressure adjusting valve 72 and the reference valve opening degree S0 does not continue to be larger than the predetermined value α (No in step S18), the process proceeds to step S16, and the control device 20 Does not change the output-pressure characteristics stored in the storage unit 22. This is because it is estimated that the difference between the valve opening S1 of the back pressure adjustment valve 72 and the reference valve opening S0 is larger than the predetermined value α due to another factor other than the water pool.

  On the other hand, when the difference between the valve opening degree S1 of the back pressure regulating valve 72 and the reference valve opening degree S0 continues to be larger than the predetermined value α (Yes in step S18), the process proceeds to step S20. When the process proceeds to step S20, the control device 20 determines whether or not the valve opening S1 of the back pressure adjustment valve 72 is larger than a predetermined value α with respect to the reference valve opening S0. That is, the control device 20 determines whether or not the valve opening S1−the reference valve opening S0> α is satisfied.

  When the valve opening degree S1 of the back pressure adjusting valve 72 is larger than the predetermined value α with respect to the reference valve opening degree S0 (Yes in step S20), the process proceeds to step S22. If transfering it to step S22, the control apparatus 20 will change the output-pressure characteristic memorize | stored in the memory | storage part 22 so that the pressure with respect to a predetermined output may fall. This is because when the valve opening S1 of the back pressure adjusting valve 72 is larger than the predetermined value α with respect to the reference valve opening S0, the fuel cell 10 has a larger amount of water in the fuel cell 10 than the allowable range. It has occurred and is estimated to be in a state of surplus water. For this reason, the pressure of the cathode gas is lowered to promote the removal of water from the fuel cell 10.

  On the other hand, if the valve opening degree S1 of the back pressure adjusting valve 72 is not larger than the predetermined value α with respect to the reference valve opening degree S0 (No in step S20), the process proceeds to step S24. That is, considering that it is determined in step S14 that | valve opening S1−reference valve opening S0 |> α is satisfied, the valve opening S1 of the back pressure regulating valve 72 is greater than the reference valve opening S0. If it is smaller than the predetermined value α (when the reference valve opening degree S0−valve opening degree S1> α), the process proceeds to step S24. If transfering it to step S24, the control apparatus 20 will change the output-pressure characteristic memorize | stored in the memory | storage part 22 so that the pressure corresponding to a predetermined output may go up. This is because when the valve opening S1 of the back pressure adjustment valve 72 is smaller than the predetermined value α with respect to the reference valve opening S0, the fuel cell 10 has an amount of water in the fuel cell 10 that is less than the allowable range. There are few, and it is estimated that it is in the dry state. For this reason, the pressure of the cathode gas is increased so that water can easily accumulate in the fuel cell 10.

  As described above, according to the first embodiment, the control device 20 acquires measured values of the temperature of the cooling water, the flow rate and pressure of the cathode gas, and the valve opening of the back pressure regulating valve 72 (see FIG. 2, the reference valve opening degree S0 is specified using the acquired cooling water temperature, the flow rate and pressure of the cathode gas, and the reference valve opening characteristic stored in the storage unit 22 (FIG. 2). Step S12). And the control apparatus 20 is with respect to the output-pressure characteristic memorize | stored in the memory | storage part 22, when the valve opening degree S1 of the acquired back pressure adjustment valve 72 is larger than predetermined value (alpha) with respect to the reference valve opening degree S0. Thus, the pressure for the predetermined output is changed (step S22 in FIG. 2). As a result, when a large amount of water is generated in the fuel cell 10 and there is a surplus of water, the removal of water from the fuel cell 10 can be promoted. As described above, according to the first embodiment, the fuel cell 10 can be controlled according to the condition corresponding to the amount of water accumulated in the fuel cell 10. Moreover, since the fuel cell 10 is controlled according to the conditions according to the amount of water accumulated, the fuel cell 10 can be efficiently generated.

  Moreover, in Example 1, the control apparatus 20 outputs the output memorize | stored in the memory | storage part 22, when the valve opening degree S1 of the acquired back pressure regulating valve 72 is smaller than predetermined value (alpha) with respect to the reference valve opening degree S0. -Change the pressure characteristic to increase the pressure for a predetermined output (step S24 in FIG. 2). As a result, when the amount of water in the fuel cell 10 is small and is in a dry state, the water can be easily collected in the fuel cell 10. Therefore, also in this case, the fuel cell 10 can be controlled according to conditions according to the amount of water accumulated in the fuel cell 10.

  In the first embodiment, the case where the predetermined value used in the determination in step 14 in FIG. 2 and the predetermined value used in the determination in step S20 in FIG. 2 are the same value α is shown as an example. It may be a value. For example, the predetermined value used in step S20 may be smaller than the predetermined value used in step S14.

  Since the configuration of the fuel cell system according to the second embodiment is the same as that of the fuel cell system 100 of the first embodiment shown in FIG. In the second embodiment, the determination unit 28 of the control device 20 determines the difference between the valve opening degree of the back pressure adjustment valve 72 acquired by the acquisition unit 24 and the reference valve opening degree specified by the specifying unit 26. In addition, the operation state of the fuel cell 10 is also determined.

  FIG. 4 is a flowchart showing an example of a change process of the output-pressure characteristic stored in the storage unit 22. As shown in FIG. 4, in step S30, the control device 20 determines whether or not the required output required for the fuel cell 10 and the flow rate and pressure of the cathode gas supplied to the fuel cell 10 are predetermined operations. To do. Such operation corresponds to, for example, when the fuel cell system 100 is mounted on a fuel cell vehicle or the like, or when the vehicle is in an idling state (for example, when the vehicle is stopped due to a signal waiting or traffic jam).

  When the required output and the cathode gas flow rate and pressure are not predetermined operations (No in step S30), the process proceeds to step S32, and the control device 20 displays the output-pressure characteristics stored in the storage unit 22. Not going to change.

  On the other hand, when the operation is such that the required output and the flow rate and pressure of the cathode gas are determined in advance (Yes in step S30), the process proceeds to step S34. In step S34, the controller 20 measures the temperature of the cooling water, the flow rate of the cathode gas, the pressure of the cathode gas, and the back pressure adjustment valve 72 measured using the temperature sensor 90, the flow rate sensor 62F, the pressure sensor 68P, and the like. Acquire the actual value of valve opening.

  After step S34, the process proceeds to step S36, and the control device 20 determines the acquired coolant temperature, the cathode gas flow rate, the cathode gas pressure, and the reference valve of the back pressure adjusting valve 72 stored in the storage unit 22. The reference valve opening degree S0 of the back pressure regulating valve 72 is specified using the opening degree characteristic. Since the method for specifying the reference valve opening degree S0 is the same as the method in the first embodiment, the description thereof is omitted.

  In step S38, the control device 20 determines whether or not the valve opening S1 of the back pressure regulating valve acquired in step S34 is larger than a predetermined value α with respect to the reference valve opening S0 specified in step S36. That is, the control device 20 determines whether or not the valve opening S1−the reference valve opening S0> α is satisfied.

  When the valve opening degree S1 of the back pressure regulating valve 72 is larger than the predetermined value α with respect to the reference valve opening degree S0 (in the case of Yes in step S38), as described in the first embodiment, it is allowed in the fuel cell 10. It is estimated that more water is generated than the range. Therefore, in this case, the process proceeds to step S40, and the control device 20 determines whether or not the valve opening degree S1 of the back pressure adjusting valve 72 continues to tend to be larger than the predetermined value α with respect to the reference valve opening degree S0. to decide. As described in the first embodiment, this is not caused by the water pool in the fuel cell 10, but the valve opening of the back pressure adjusting valve 72 is predetermined with respect to the reference valve opening due to some other accidental factor. The case where it becomes larger than the value is excluded.

  When the valve opening S1 of the back pressure regulating valve 72 continues to tend to be larger than the predetermined value α with respect to the reference valve opening S0 (in the case of Yes in step S40), the process proceeds to step S42, and the control device 20 The output-pressure characteristic stored in the storage unit 22 is changed so that the pressure corresponding to the predetermined output decreases. As a result, the pressure of the cathode gas is lowered, so that the removal of water from the fuel cell 10 can be promoted.

  On the other hand, when the valve opening S1 of the back pressure adjusting valve 72 is smaller than the predetermined value α with respect to the reference valve opening S0 (No in step S38), the amount of water in the fuel cell 10 is within an allowable range. Since it is estimated that there is, the control device 20 proceeds to step S32 and does not change the output-pressure characteristic. In addition, if the valve opening S1 of the back pressure adjusting valve 72 does not continue to tend to be larger than the predetermined value α with respect to the reference valve opening S0 (No in step S40), it is determined by another factor other than the water pool. Since it is estimated that the value α is greater than the value α, the control device 20 proceeds to step S32 and does not change the output-pressure characteristic.

  As described above, according to the second embodiment, the control device 20 first performs an operation in which the required output required for the fuel cell 10 and the flow rate and pressure of the cathode gas supplied to the fuel cell 10 are determined in advance. (Step S30 in FIG. 4). When it is determined that the operation is determined in advance, the control device 20 stores the storage unit when the acquired valve opening S1 of the back pressure adjustment valve 72 is larger than the predetermined value α with respect to the reference valve opening S0. The output-pressure characteristic stored in 22 is changed to lower the pressure for a predetermined output (step S42 in FIG. 4). The valve opening S1 of the back pressure adjusting valve 72 with respect to the reference valve opening S0 in a situation where the required output required for the fuel cell 10 and the flow rate and pressure of the cathode gas supplied to the fuel cell 10 fluctuate. The determination as to whether or not the value is larger than the predetermined value α may not provide good determination accuracy. However, as in the second embodiment, it is determined whether the required output required for the fuel cell 10 and the flow rate and pressure of the cathode gas supplied to the fuel cell 10 are determined in advance. In this case, it is possible to improve the determination accuracy by determining whether or not the valve opening S1 of the back pressure adjusting valve 72 is larger than the predetermined value α with respect to the reference valve opening S0.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Fuel cell 20 Control apparatus 22 Memory | storage part 24 Acquisition part 26 Identification part 28 Judgment part 30 Change part 40 Anode gas supply flow path 50 Anode gas discharge flow path 54 Circulation pump 60 Air cleaner 62 Air compressor 62F Flow rate sensor 68 Cathode gas supply flow path 68P Pressure sensor 70 Cathode gas discharge passage 72 Back pressure regulating valve 80 Water pump 82 Water passage 84 Radiator 90, 92 Temperature sensor 100 Fuel cell system

Claims (1)

The relationship between the required output required for the fuel cell, the output of the fuel cell and the flow rate of the cathode gas supplied to the fuel cell, determined for each temperature of the cooling water flowing through the fuel cell, and the fuel cell In the fuel cell system for controlling the flow rate and pressure of the cathode gas based on the relationship between the output and the pressure of the cathode gas,
A back pressure adjusting valve that adjusts the pressure of the cathode gas based on a pressure sensor provided in a supply path of the cathode gas supplied to the fuel cell;
A storage unit that stores a reference valve opening characteristic that defines a reference valve opening of the back pressure regulating valve with respect to the flow rate and pressure of the cathode gas for each temperature of the cooling water;
An acquisition unit for acquiring an actual measurement value of the cooling water temperature, the flow rate of the cathode gas, the pressure of the cathode gas, and the valve opening of the back pressure regulating valve;
Using the temperature of the cooling water acquired by the acquisition unit, the flow rate of the cathode gas, and the pressure of the cathode gas, and the reference valve opening characteristic stored in the storage unit, the back pressure adjustment valve A specific part for specifying the reference valve opening of
When the valve opening of the back pressure regulating valve acquired by the acquiring unit is larger than a predetermined value with respect to the reference valve opening specified by the specifying unit, the output of the fuel cell and the pressure of the cathode gas A change is made to lower the pressure for a predetermined output with respect to the relationship, and the valve opening degree of the back pressure regulating valve acquired by the acquisition unit is smaller than a predetermined value with respect to the reference valve opening degree specified by the specifying unit A fuel cell system comprising: a change unit configured to change the relationship between the output of the fuel cell and the pressure of the cathode gas to increase a pressure with respect to a predetermined output.

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