JP2009076243A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system in which a breakdown due to a surging in an air-compressor connected with an air supply tube is controlled or prevented. <P>SOLUTION: In the fuel cell system 100, a controlling unit 70 judges whether a surging occurs or not in an air-compressor 32 based on a variation ratio of a pressure detected by a pressure sensor 37. When it is judged that the surging occurs in the air-compressor 32, the controlling unit 70 lowers a rotating frequency of a motor 32m provided on the air-compressor 32 to cancel the surging. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system.

  A fuel cell that generates electricity by an electrochemical reaction between a fuel gas (for example, hydrogen) and an oxidant gas (for example, oxygen) has attracted attention as an energy source. In a fuel cell system including this fuel cell, hydrogen as a fuel gas is generally supplied to the anode of the fuel cell, for example, from a hydrogen tank via a hydrogen supply pipe in response to an output request for the fuel cell. In general, compressed air compressed by an air compressor is supplied to the cathode of the fuel cell as an oxidant gas via an air supply pipe in response to an output request to the fuel cell. Conventionally, various techniques for adjusting the pressure in the air supply pipe have been proposed in the fuel cell system.

JP-A-8-78035 JP-A-11-303653 JP-A-7-105963 JP 2005-98255 A JP-A-7-208200

  By the way, in an air compressor, it is known that surging occurs under operating conditions of low flow rate and high compression. If surging occurs in the air compressor, the air compressor or the fuel cell system may be damaged.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to suppress or prevent failure due to surging in an air compressor connected to an air supply pipe in a fuel cell system.

  The present invention can be realized as the following forms or application examples in order to solve at least a part of the above-described problems.

  [Application Example 1] A fuel cell system, wherein a fuel cell generates power by an electrochemical reaction between hydrogen and oxygen, an air supply pipe for supplying air containing oxygen to the cathode of the fuel cell, An air compressor connected to the air supply pipe for compressing the air and flowing it through the air supply pipe, and a motor control for controlling the number of revolutions of a motor provided in the air compressor in response to an output request to the fuel cell A surging detector that detects occurrence of surging in the air compressor, and a pressure in the air supply pipe so as to eliminate the surging when the occurrence of surging is detected by the surging detector And a pressure control unit for controlling the fuel cell system.

  As described above, in the air compressor, surging occurs under operating conditions of low flow rate and high compression. In the air compressor, the operating condition in which surging occurs can be known in advance according to the specifications and performance of the air compressor.

  In the fuel cell system of Application Example 1, when the surging detection unit detects the occurrence of surging in the air compressor, the pressure control unit controls the pressure in the air supply pipe so as to eliminate the surging. Therefore, when surging occurs in the air compressor, the operating condition of the air compressor at that time can be prevented from satisfying the operating condition where surging occurs. As a result, in the fuel cell system, failure due to surging in the air compressor connected to the air supply pipe can be suppressed.

  [Application Example 2] The fuel cell system according to Application Example 1, wherein the pressure control unit detects the occurrence of the surging by the surging detection unit regardless of the output request. A fuel cell system that controls a pressure in the air supply pipe by controlling a rotation speed.

  In the fuel cell system of Application Example 2, when surging occurs in the air compressor, the pressure in the air supply pipe is controlled by controlling the rotation speed of the motor included in the air compressor regardless of the output request to the fuel cell. To do. Therefore, the operating condition of the air compressor can be prevented from satisfying the operating condition where surging occurs.

  [Application Example 3] The fuel cell system according to Application Example 2, wherein the pressure control unit detects the occurrence of surging when the surging detection unit detects the occurrence of surging. The pressure in the air supply pipe and the flow rate of air flowing in the air supply pipe are acquired, and the rotation speed of the motor is less than a predetermined rotation speed defined based on the pressure and the flow rate. A fuel cell system that reduces the rotational speed to a rotational speed other than 0 revolutions / minute.

  [Application Example 4] The fuel cell system according to Application Example 2, wherein the pressure control unit detects the occurrence of the surging when the surging detection unit detects the occurrence of the surging. The pressure in the air supply pipe and the flow rate of the air flowing in the air supply pipe are acquired, and the rotational speed of the motor is set to be higher than a predetermined rotational speed defined based on the pressure and the flow rate. A fuel cell system that increases the rotational speed.

  In the air compressor, the operating region (operating condition) where surging occurs can be known in advance according to the specifications and performance of the air compressor. Further, in the air compressor, the number of rotations of the motor that generates surging varies depending on the pressure in the air supply pipe and the flow rate of the air flowing in the air supply pipe.

  In the fuel cell system of Application Example 3 or Application Example 4, when surging occurs in the air compressor, the operating condition of the air compressor is reduced by increasing or decreasing the rotation speed of the motor included in the air compressor. It is possible to prevent the operating condition for generating surging from being satisfied.

  [Application Example 5] The fuel cell system according to Application Example 1, wherein the pressure control unit is branched and connected from the air supply pipe and exhausts the air flowing through the air supply pipe to the outside. A pipe and an exhaust valve disposed in the exhaust pipe, and when the occurrence of the surging is detected by the surging detection unit, the exhaust valve is controlled to be opened and closed to thereby control the air. A fuel cell system that controls the pressure in the supply piping.

  In the fuel cell system of Application Example 5, when surging occurs in the air compressor, the pressure in the air supply pipe is reduced by performing opening / closing control of the exhaust valve. By doing so, the operating condition of the air compressor can be prevented from satisfying the operating condition in which surging occurs.

  Application Example 6 The fuel cell system according to Application Example 5, wherein the opening / closing control of the exhaust valve includes control of at least one of an opening degree and a valve opening time of the exhaust valve.

  [Application Example 7] The fuel cell system according to Application Example 6, wherein the pressure control unit detects the occurrence of the surging when the surging detection unit detects the occurrence of the surging. Obtaining the pressure in the air supply pipe and the flow rate of air flowing through the air supply pipe, and based on the pressure and the flow rate, at least the opening degree of the exhaust valve and the valve opening time One side is set to the predetermined value prescribed | regulated based on the said pressure and the said flow volume, The fuel cell system.

  In the fuel cell system of Application Example 7, when surging occurs in the air compressor, at least one of the opening degree of the exhaust valve and the valve opening time is controlled to be set to a predetermined value, thereby controlling the air supply pipe. Reduce the pressure inside. By doing so, the operating condition of the air compressor can be prevented from satisfying the operating condition in which surging occurs. Note that at least one of the opening degree and the valve opening time of the exhaust valve can be arbitrarily set within a range in which surging in the air compressor can be eliminated.

  Application Example 8 In the fuel cell system according to any one of Application Examples 5 to 7, the surging detection unit includes a pressure sensor that detects a pressure in the air supply pipe, and the exhaust pipe includes The fuel cell system connected to the site | part between the said pressure sensor and the said fuel cell in air supply piping.

  By doing so, surging in the air compressor can be detected with higher precision than in the case where the pressure sensor is disposed in a portion between the exhaust valve and the fuel cell in the air supply pipe.

  Application Example 9 In the fuel cell system according to any one of Application Examples 1 to 7, the surging detection unit flows through the pressure sensor that detects the pressure in the air supply pipe and the air supply pipe. A fuel cell system comprising at least one of a flow sensor for detecting a flow rate of air and a vibration sensor for detecting vibration of the air compressor.

  When surging occurs in the air compressor, the absolute value of the rate of change in pressure in the air supply pipe is larger than when surging does not occur. Further, when surging occurs in the air compressor, the absolute value of the rate of change of the flow rate of the air flowing through the air supply pipe becomes larger than when surging does not occur. Further, when surging occurs in the air compressor, the vibration frequency of the motor included in the air compressor is smaller than that in the case where surging does not occur.

  In the fuel cell system of Application Example 9, since the surging detection unit includes at least one of the pressure sensor, the flow rate sensor, and the vibration sensor, surging in the air compressor can be easily detected. it can.

  Application Example 10 In a fuel cell system, a fuel cell that generates power by an electrochemical reaction between hydrogen and oxygen, an air supply pipe for supplying the oxygen-containing air to the cathode of the fuel cell, An air compressor connected to the air supply pipe for compressing the air and flowing it through the air supply pipe, and a controller for controlling the number of revolutions of a motor included in the air compressor in response to an output request to the fuel cell And the pressure in the air supply pipe and the flow rate of the air flowing in the air supply pipe are acquired, and the air is avoided so as to avoid surging in the air compressor based on the pressure and the flow rate. And a pressure control unit that controls the pressure in the supply pipe.

  As described above, in the air compressor, surging occurs under operating conditions of low flow rate and high compression. In the air compressor, the operating condition in which surging occurs can be known in advance according to the specifications and performance of the air compressor.

  In the fuel cell system of Application Example 10, the pressure control unit prevents surging from occurring in the air compressor based on the pressure in the air supply pipe and the flow rate of the air flowing in the air supply pipe. The pressure in the air supply pipe is controlled so that the operating condition of the air compressor does not satisfy the operating condition in which surging occurs. Therefore, in the fuel cell system, failure due to surging in the air compressor connected to the air supply pipe can be prevented.

  [Application Example 11] The fuel cell system according to Application Example 10, wherein the pressure control unit determines whether the rotation speed of the motor corresponding to the output request is the rotation speed at which the surging occurs in the air compressor. Whether or not the rotation speed of the motor corresponding to the output request is the rotation speed at which the surging occurs in the air compressor, regardless of the output request. The fuel cell system which controls the pressure in the said air supply piping by controlling.

  In the fuel cell system of Application Example 11, when the air compressor is operated at a rotation speed corresponding to the required output for the fuel cell, it is determined that surging occurs in the air compressor, regardless of the output request for the fuel cell. The pressure in the air supply pipe is controlled by controlling the number of rotations of the motor included in. Therefore, it is possible to prevent the operating condition of the air compressor from satisfying the operating condition in which surging occurs in advance.

  Application Example 12 In the fuel cell system according to Application Example 11, in the pressure control unit, the rotation speed of the motor corresponding to the output request is a rotation speed at which the surging occurs in the air compressor. When judged, based on the pressure and the flow rate, the rotational speed of the motor is less than a predetermined rotational speed defined based on the pressure and the flow rate, and is 0 rotation A fuel cell system that reduces the rotational speed to less than / min.

  Application Example 13 In the fuel cell system according to Application Example 11, in the pressure control unit, the rotation speed of the motor corresponding to the output request is a rotation speed at which the surging occurs in the air compressor. A fuel that, when determined, increases the rotational speed of the motor based on the pressure and the flow rate to a rotational speed higher than a predetermined rotational speed defined based on the pressure and the flow rate; Battery system.

  In the fuel cell system of Application Example 12 or Application Example 13, when it is determined that surging occurs in the air compressor when the air compressor is operated at a rotational speed corresponding to the required output for the fuel cell, the motor included in the air compressor The operating condition of the air compressor can be prevented from satisfying the operating condition for generating surging in advance by lowering or increasing the rotating speed of the air compressor below the rotational speed corresponding to the output request for the fuel cell. .

  [Application Example 14] The fuel cell system according to Application Example 10, wherein the pressure control unit is branched and connected from the air supply pipe and exhausts the air flowing in the air supply pipe to the outside. And when the rotational speed of the motor corresponding to the output request is determined to be the rotational speed at which the surging occurs in the air compressor. In addition, the fuel cell system controls the pressure in the air supply pipe by controlling the opening and closing of the exhaust valve.

  In the fuel cell system of Application Example 14, when the air compressor is operated at a rotational speed corresponding to the required output for the fuel cell, when it is determined that surging occurs in the air compressor, the opening / closing control of the exhaust valve is performed. Reduce the pressure in the air supply piping. By doing so, it is possible to prevent the operating condition of the air compressor from satisfying the operating condition in which surging occurs in advance.

  Application Example 15 The fuel cell system according to Application Example 14, wherein the opening / closing control of the exhaust valve includes control of at least one of an opening degree and a valve opening time of the exhaust valve.

  Application Example 16 In the fuel cell system according to Application Example 15, in the pressure control unit, the rotation speed of the motor corresponding to the output request is a rotation speed at which the surging occurs in the air compressor. A fuel cell system that, when determined, sets at least one of an opening degree and a valve opening time of the exhaust valve to a predetermined value defined based on the pressure and the flow rate.

  In the fuel cell system of Application Example 16, when it is determined that surging occurs in the air compressor when the air compressor is operated at a rotational speed corresponding to the required output for the fuel cell, the opening degree of the exhaust valve and the valve opening are determined. By controlling at least one of the times by setting to a predetermined value, the pressure in the air supply pipe is reduced. By doing so, it is possible to prevent the operating condition of the air compressor from satisfying the operating condition in which surging occurs in advance. Note that at least one of the opening degree and the valve opening time of the exhaust valve can be arbitrarily set within a range in which surging in the air compressor can be avoided.

  Application Example 17 The fuel cell system according to any one of Application Examples 1 to 16, wherein the air compressor is a turbo type air compressor.

  Since surging is likely to occur in a turbo type air compressor, this application example is particularly effective.

  [Application Example 18] The fuel cell system according to any one of Application Examples 1 to 17, wherein the fuel cell system is for vehicle use.

  In the fuel cell system for in-vehicle use, the output requirement for the fuel cell changes abruptly according to the accelerator operation of the driver of the vehicle, so that the output requirement for the fuel cell is less likely to change abruptly. , Surging is likely to occur. Therefore, it is particularly suitable to use the above-described fuel cell system for in-vehicle use.

  The present invention can be configured as an invention of a control method of a fuel cell system in addition to the above-described configuration as a fuel cell system. Further, the present invention can be realized in various modes such as a computer program that realizes these, a recording medium that records the program, and a data signal that includes the program and is embodied in a carrier wave. In addition, in each aspect, it is possible to apply the various additional elements shown above.

  When the present invention is configured as a computer program or a recording medium storing the program, the entire program for controlling the operation of the fuel cell system may be configured, or only the portion that performs the function of the present invention is configured. It is good also as what to do. The recording medium includes a flexible disk, a CD-ROM, a DVD-ROM, a magneto-optical disk, an IC card, a ROM cartridge, a punch card, a printed matter on which a code such as a barcode is printed, a computer internal storage device (RAM or Various types of computer-readable media such as a memory such as a ROM and an external storage device can be used.

Hereinafter, embodiments of the present invention will be described based on examples.
A. First embodiment:
A1. Configuration of fuel cell system:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system 100 as a first embodiment of the present invention. The fuel cell system 100 is mounted on a so-called electric vehicle as a power source.

  In the fuel cell system 100, the fuel cell stack 10 is a stacked body in which a plurality of cells that generate power by an electrochemical reaction between hydrogen and oxygen are stacked. Each cell has a configuration in which an anode (hydrogen electrode) and a cathode (oxygen electrode) are arranged with an electrolyte membrane having proton conductivity interposed therebetween (not shown). In this embodiment, a solid polymer type cell using a solid polymer membrane such as Nafion (registered trademark) is used as the electrolyte membrane, but the present invention is not limited to this, and various types can be used.

  Hydrogen as fuel gas is supplied to the anode of the fuel cell stack 10 from a hydrogen tank 20 that stores high-pressure hydrogen via a hydrogen supply pipe 23. Instead of the hydrogen tank 20, for example, a hydrogen generator that generates hydrogen by a reforming reaction using alcohol, hydrocarbon, aldehyde, or the like as a raw material may be used.

  The high pressure hydrogen stored in the hydrogen tank 20 is supplied to the anode of the fuel cell stack 10 after the pressure and supply amount are adjusted by a shut valve 21, a regulator 22, and the like provided at the outlet of the hydrogen tank 20. Exhaust gas from the anode (hereinafter referred to as anode off gas) is introduced into the gas-liquid separator 25 via the pipe 24. The gas-liquid separator 25 separates water contained in the anode off-gas from unconsumed hydrogen generated by the power generation by the fuel cell stack 10. The hydrogen separated by the gas-liquid separator 25 can be recirculated to the hydrogen supply pipe 23 via the circulation pipe 26. A piping 28 is branched and connected between the gas-liquid separator 25 and the circulation pump 27 in the circulation piping 26, and a purge valve 29 is disposed in the piping 28. While the purge valve 29 is closed, the anode off-gas, that is, hydrogen separated by the gas-liquid separator 25 is circulated again to the fuel cell stack 10 via the circulation pipe 26. In this way, hydrogen can be used effectively. 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 stack 10, and therefore the anode off gas is added to the circulation pipe 26 when the anode off gas is recirculated. A circulation pump 27 for pressure is provided.

  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 through the electrolyte membrane remains without being consumed. The concentration of impurities inside increases gradually. At this time, when the purge valve 29 is opened, the anode off-gas is introduced into the diluter 50 via the pipe 28 and is diluted with the cathode off-gas in the diluter 50, as will be described later. It is discharged outside the system 100. By doing so, the concentration of impurities in the anode off-gas can be reduced. However, at this time, since hydrogen is also discharged at the same time, it is preferable to suppress the opening frequency of the purge valve 29 as much as possible from the viewpoint of improving fuel efficiency.

  The cathode of the fuel cell stack 10 is supplied with compressed air as an oxidant gas containing oxygen. Air is taken in from the air cleaner 30, compressed by an air compressor 32 including a motor 32 m, and supplied from the air supply pipe 34 to the cathode of the fuel cell stack 10. In this embodiment, the air supply pipe 34 includes a pressure sensor 37 for detecting the pressure in the air supply pipe 34, and a flow rate sensor 38 for detecting the flow rate of air flowing in the air supply pipe 34. Is arranged. Exhaust gas from the cathode (hereinafter referred to as cathode off gas) flows out to the pipe 36. The pipe 36 is provided with an air pressure regulating valve 35, and the air pressure in the fuel cell stack 10 can be controlled by controlling the air pressure regulating valve 35.

  The cathode offgas that has flowed into the pipe 36 and the anode offgas that has flowed into the pipe 28 when the purge valve 29 is opened are introduced into the diluter 50. The diluter 50 dilutes the concentration of hydrogen contained in the anode off gas by mixing the anode off gas and the cathode off gas. The exhaust gas discharged from the diluter 50 is discharged to the outside of the fuel cell system 100 via the pipe 60.

  Since the fuel cell stack 10 generates heat by the above-described electrochemical reaction, cooling water is also supplied to the fuel cell stack 10. The cooling water flows through the cooling water pipe 42 by the circulation pump 41, is cooled by the radiator 40, and is supplied to the fuel cell stack 10. In addition, as shown in the drawing, a bypass pipe 43 for circulating the cooling water without passing through the radiator 40 is connected to the pipe 42, and further, at one connection portion between the pipe 42 and the bypass pipe 43. Is provided with a three-way valve 44. Therefore, by switching the three-way valve 44, it is possible to circulate the cooling water through the pipe 42 and the bypass pipe 43 without passing through the radiator 40. Further, an ion exchanger 45 is connected to the pipe 42 via a pipe 46 as shown in the figure. The ion exchanger 45 removes various ions contained in the cooling water that cause an increase in the conductivity of the fuel cell stack 10.

  The operation of the fuel cell system 100 is controlled by the control unit 70. The control unit 70 is configured as a microcomputer having a CPU, a RAM, a ROM, and the like inside, and in accordance with a program stored in the ROM, based on output requests to the fuel cell stack 10, outputs from various sensors, and the like. Control of system operation such as driving of valves, circulation pumps 27 and 41, and air compressor 32 is controlled. The control unit 70 corresponds to a motor control unit and a pressure control unit in the present invention.

  In the fuel cell system 100 of the present embodiment, the air compressor 32 is a turbo type air compressor, and surging is likely to occur under low flow and high compression operating conditions. Therefore, in the fuel cell system 100 of the present embodiment, when surging occurs in the air compressor 32, operation control for eliminating this surging is performed. Hereinafter, operation control for eliminating surging in the air compressor 32 will be described.

A2. Operation control processing:
FIG. 2 is a flowchart showing a flow of operation control processing of the fuel cell system 100 of the first embodiment. This process is performed during operation of the fuel cell system 100, that is, when hydrogen and air are supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10, respectively. This process is repeatedly executed by the CPU of the control unit 70.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow sensor 38, respectively (step S100). Store the value in RAM. As will be described later, these detection values are used to determine whether surging has occurred in the air compressor 32 and to control the number of revolutions of the motor 32m included in the air compressor 32 when surging has occurred in the air compressor 32. Used for.

  Next, the CPU calculates a change rate ΔP of the pressure P in the air supply pipe 34 (step S110), and determines whether or not the absolute value | ΔP | of the change rate of the pressure P is larger than a predetermined threshold value Pth. Judgment is made (step S120). When the absolute value | ΔP | of the rate of change of the pressure P is larger than the threshold value Pth (step S120: YES), the CPU determines that surging has occurred in the air compressor 32 and determines that the fuel cell stack 10 Regardless of the output request, the rotational speed of the motor 32m provided in the air compressor 32 is reduced to a predetermined rotational speed (excluding 0 rotation / minute) (step S130). In the present embodiment, the pressure sensor 37 and the control unit 70 correspond to a surging detection unit in the present invention.

  In this embodiment, when it is determined that surging has occurred in the air compressor 32 as the number of rotations of the motor 32m at this time, that is, when surging in the air compressor 32 is detected, A value defined in advance based on the pressure P and the flow rate Fr of the air flowing in the air supply pipe 34 is used. This value changes according to the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and is set within a range in which surging in the air compressor 32 can be eliminated. In this embodiment, a map in which the relationship between the pressure P in the air supply pipe 34, the flow rate Fr of the air flowing through the air supply pipe 34, and the rotation speed of the motor 32m to be set is stored in the ROM in advance. It was supposed to be.

  In step S120, when the absolute value | ΔP | of the rate of change of the pressure P in the air supply pipe 34 is equal to or less than the threshold value Pth (step S120: NO), the CPU is surging in the air compressor 32. It is determined that there is no operation, the operation control process described above is terminated, and the process returns to step S100.

  According to the fuel cell system 100 of the first embodiment described above, when the occurrence of surging in the air compressor 32 is detected, the air so as to eliminate the surging regardless of the output request to the fuel cell stack 10. The rotational speed of the motor 32m provided in the compressor 32 is reduced to a predetermined rotational speed. By so doing, surging in the air compressor 32 can be quickly eliminated, and in the fuel cell system 100, failure due to surging of the air compressor 32 can be suppressed.

B. Second embodiment:
The configuration of the fuel cell system of the second embodiment is the same as that of the fuel cell system 100 of the first embodiment described above, and detailed description of each part is omitted. In the fuel cell system of the second embodiment, the content of the operation control performed by the control unit 70, specifically, the surging detection method in the air compressor 32 is different from the first embodiment. Hereinafter, operation control of the fuel cell system of the second embodiment will be described.

  FIG. 3 is a flowchart showing a flow of operation control processing of the fuel cell system of the second embodiment. This process is performed during operation of the fuel cell system, that is, when hydrogen and air are respectively supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10. This process is repeatedly executed by the CPU of the control unit 70.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow rate sensor 38, respectively (step S200). Store the value in RAM. As will be described later, these detection values are used to determine whether surging has occurred in the air compressor 32 and to control the number of revolutions of the motor 32m included in the air compressor 32 when surging has occurred in the air compressor 32. Used for.

  Next, the CPU calculates a change rate ΔFr of the flow rate Fr of the air flowing in the air supply pipe 34 (step S210), and whether the absolute value | ΔFr | of the change rate of the flow rate Fr is greater than a predetermined threshold value Frth. It is determined whether or not (step S220). When the absolute value | ΔFr | of the rate of change of the flow rate Fr is larger than the threshold value Frth (step S220: YES), the CPU determines that surging has occurred in the air compressor 32 and determines that the fuel cell stack 10 Regardless of the output request, the rotation speed of the motor 32m provided in the air compressor 32 is reduced to a predetermined rotation speed (excluding 0 rotation / min) (step S230). In the present embodiment, the flow sensor 38 and the control unit 70 correspond to a surging detection unit in the present invention.

  Also in this embodiment, as in the first embodiment, when it is determined that surging has occurred in the air compressor 32, that is, surging in the air compressor 32 is detected as the rotation speed of the motor 32m at this time. In this case, a value defined in advance based on the pressure P in the air 34 and the flow rate Fr of the air flowing in the air supply pipe 34 is used. This value changes according to the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and is set within a range in which surging in the air compressor 32 can be eliminated. Also in this embodiment, a map in which the relationship between the pressure P in the air supply pipe 34 and the flow rate Fr of the air flowing in the air supply pipe 34 and the rotation speed of the motor 32m to be set is recorded in the ROM in advance. It was assumed that it was remembered.

  In step S220, when the absolute value | ΔFr | of the rate of change of the flow rate Fr of the air flowing in the air supply pipe 34 is equal to or less than the threshold value Frth (step S220: NO), the CPU performs surging in the air compressor 32. It judges that it has not generate | occur | produced, complete | finishes the driving | operation control process mentioned above, and returns to step S200.

  Also in the fuel cell system of the second embodiment described above, when the occurrence of surging in the air compressor 32 is detected, similarly to the fuel cell system 100 of the first embodiment described above, Regardless of the output request, the rotational speed of the motor 32m provided in the air compressor 32 is reduced to a predetermined rotational speed so as to eliminate the surging. By so doing, surging in the air compressor 32 can be quickly eliminated, and failure due to surging of the air compressor 32 can be suppressed in the fuel cell system.

C. Third embodiment:
FIG. 4 is an explanatory diagram showing a schematic configuration of a fuel cell system 100A as a third embodiment of the present invention. The configuration of the fuel cell system 100A of the third embodiment is substantially the same as that of the fuel cell system 100 of the first embodiment described above, and detailed description of each part is omitted. In 100A of the third embodiment, a vibration sensor 33 is provided in the air compressor 32, and surging in the air compressor 32 is detected using the vibration sensor 33. Further, in the fuel cell system 100A of the third embodiment, the content of the operation control executed by the control unit 70A is different from that of the first embodiment. Hereinafter, operation control of the fuel cell system 100A of the third embodiment will be described.

  FIG. 5 is a flowchart showing a flow of operation control processing of the fuel cell system 100A of the third embodiment. This process is performed during operation of the fuel cell system 100A, that is, when hydrogen and air are supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10, respectively. This process is repeatedly executed by the CPU of the control unit 70A.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow rate sensor 38, respectively (step S300). Store the value in RAM. As will be described later, these detected values are used to control the number of revolutions of a motor 32m provided in the air compressor 32 when surging occurs in the air compressor 32.

  Next, the CPU detects vibration of the motor 32m included in the air compressor 32 by the vibration sensor 33, calculates the frequency f (step S310), and determines whether the frequency f is less than a predetermined threshold fth. Is determined (step S320). When the frequency f is less than the threshold fth (step S320: YES), the CPU determines that surging has occurred in the air compressor 32, and the air compressor 32 regardless of the output request to the fuel cell stack 10. Is reduced to a predetermined number of rotations (excluding 0 rotations / minute) (step S330). In the present embodiment, the vibration sensor 33 and the control unit 70A correspond to a surging detection unit in the present invention.

  Also in this embodiment, as in the first and second embodiments, when it is determined that surging has occurred in the air compressor 32 as the rotational speed of the motor 32m at this time, that is, the air A value defined in advance based on the pressure P in the air supply pipe 34 when surging in the compressor 32 is detected and the flow rate Fr of the air flowing in the air supply pipe 34 is used. This value changes according to the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and is set within a range in which surging in the air compressor 32 can be eliminated. Also in this embodiment, a map in which the relationship between the pressure P in the air supply pipe 34 and the flow rate Fr of the air flowing in the air supply pipe 34 and the rotation speed of the motor 32m to be set is recorded in the ROM in advance. It was assumed that it was remembered.

  If the vibration frequency f of the motor 32m provided in the air compressor 32 is equal to or higher than the threshold value fth in step S320 (step S320: NO), the CPU determines that surging has not occurred in the air compressor 32. Then, the operation control process described above is terminated, and the process returns to step S300.

  Also in the fuel cell system of the third embodiment described above, when the occurrence of surging in the air compressor 32 is detected, similarly to the fuel cell system 100 of the first embodiment described above, Regardless of the output request, the rotational speed of the motor 32m provided in the air compressor 32 is reduced to a predetermined rotational speed so as to eliminate the surging. By so doing, surging in the air compressor 32 can be quickly eliminated, and failure due to surging of the air compressor 32 can be suppressed in the fuel cell system.

D. Fourth embodiment:
FIG. 6 is an explanatory diagram showing a schematic configuration of a fuel cell system 100B as a fourth embodiment of the present invention. The configuration of the fuel cell system 100B of the fourth embodiment is substantially the same as that of the fuel cell system 100 of the first embodiment described above, and a detailed description of each part is omitted. In the fuel cell system 100B of the fourth embodiment, an exhaust pipe 39 is branched and connected from a portion of the air supply pipe 34 between the pressure sensor 37 and the fuel cell stack 10, and the exhaust pipe 39 is connected to the exhaust pipe 39. Is provided with an exhaust valve 39Vr. In this embodiment, the exhaust valve 39Vr is an exhaust valve whose opening degree can be adjusted. Further, in the fuel cell system 100B of the fourth embodiment, the content of the operation control executed by the control unit 70B is different from that of the first embodiment. Hereinafter, operation control of the fuel cell system 100B of the fourth embodiment will be described.

  FIG. 7 is a flowchart showing a flow of operation control processing of the fuel cell system 100B of the fourth embodiment. This process is performed when the fuel cell system 100B is in operation, that is, when hydrogen and air are supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10, respectively. This process is repeatedly executed by the CPU of the control unit 70B.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow rate sensor 38, respectively (step S400). Store the value in RAM. As will be described later, these detected values are used to determine whether surging has occurred in the air compressor 32 and to control opening / closing of the exhaust valve 39Vr when surging has occurred in the air compressor 32.

  Next, the CPU calculates a change rate ΔP of the pressure P in the air supply pipe 34 (step S410), and determines whether or not the absolute value | ΔP | of the change rate of the pressure P is larger than a predetermined threshold value Pth. Judgment is made (step S420). When the absolute value | ΔP | of the change rate of the pressure P is larger than the threshold value Pth (step S420: YES), the CPU determines that surging has occurred in the air compressor 32 and opens the exhaust valve 39Vr. Valve (step S430) and reduce the pressure in the air supply pipe 34. In the present embodiment, the pressure sensor 37 and the control unit 70B correspond to a surging detection unit in the present invention.

  In the present embodiment, when surging occurs in the air compressor 32, that is, when surging in the air compressor 32 is detected as the opening degree and the valve opening time of the exhaust valve 39Vr at this time, the air supply pipe It is assumed that values specified in advance based on the pressure P in 34 and the flow rate Fr of air flowing in the air supply pipe 34 are used. These values vary depending on the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and are set within a range in which surging in the air compressor 32 can be eliminated. In this example, the relationship between the pressure P in the air supply pipe 34, the flow rate Fr of the air flowing in the air supply pipe 34, the opening degree of the exhaust valve 39Vr to be set, and the valve opening time was recorded. The map was previously stored in the ROM.

  In step S420, if the absolute value | ΔP | of the rate of change of the pressure P in the air supply pipe 34 is equal to or less than the threshold value Pth (step S420: NO), the CPU is surging in the air compressor 32. It is determined that there is no operation, the operation control process described above is terminated, and the process returns to step S400.

  According to the fuel cell system 100B of the fourth embodiment described above, when the occurrence of surging in the air compressor 32 is detected, the exhaust valve 39Vr is opened to eliminate the surging, and the air supply pipe The pressure in 34 is reduced. By so doing, surging in the air compressor 32 can be quickly eliminated, and failure due to surging of the air compressor 32 can be suppressed in the fuel cell system 100B.

E. Example 5:
The configuration of the fuel cell system of the fifth embodiment is the same as that of the fuel cell system 100B of the fourth embodiment described above, and a detailed description of each part is omitted. In the fuel cell system of the fifth embodiment, the content of the operation control executed by the control unit 70B, specifically, the surging detection method in the air compressor 32 is different from that of the fourth embodiment. Hereinafter, operation control of the fuel cell system of the fifth embodiment will be described.

  FIG. 8 is a flowchart showing a flow of operation control processing of the fuel cell system of the fifth embodiment. This process is performed during operation of the fuel cell system, that is, when hydrogen and air are respectively supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10. This process is repeatedly executed by the CPU of the control unit 70A.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow sensor 38, respectively (step S500). Store the value in RAM. As will be described later, these detected values are used to determine whether surging has occurred in the air compressor 32 and to control opening / closing of the exhaust valve 39Vr when surging has occurred in the air compressor 32.

  Next, the CPU calculates a change rate ΔFr of the flow rate Fr of the air flowing in the air supply pipe 34 (step S510), and whether the absolute value | ΔFr | of the change rate of the flow rate Fr is larger than a predetermined threshold value Frth. It is determined whether or not (step S520). When the absolute value | ΔFr | of the change rate of the flow rate Fr is larger than the threshold value Frth (step S520: YES), the CPU determines that surging has occurred in the air compressor 32 and opens the exhaust valve 39Vr. Valve (step S530) and reduce the pressure in the air supply pipe 34. In the present embodiment, the flow sensor 38 and the control unit 70 correspond to a surging detection unit in the present invention.

  Also in this embodiment, as in the fourth embodiment, when it is determined that surging has occurred in the air compressor 32 as the opening degree of the exhaust valve 39Vr and the valve opening time at this time, that is, the air The values defined in advance based on the pressure P in the air supply pipe 34 when surging in the compressor 32 is detected and the flow rate Fr of air flowing in the air supply pipe 34 are used. These values vary depending on the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and are set within a range in which surging in the air compressor 32 can be eliminated. Also in the present embodiment, the relationship between the pressure P in the air supply pipe 34, the flow rate Fr of the air flowing in the air supply pipe 34, the opening degree of the exhaust valve 39Vr to be set, and the valve opening time. It is assumed that a map in which is recorded in advance in the ROM.

  In step S520, when the absolute value | ΔFr | of the change rate of the flow rate Fr of the air flowing in the air supply pipe 34 is equal to or less than the threshold value Frth (step S520: NO), the CPU performs surging in the air compressor 32. It judges that it has not generate | occur | produced, complete | finishes the operation control process mentioned above, and returns to step S500.

  The fuel cell system of the fifth embodiment described above also eliminates the surging when the occurrence of surging in the air compressor 32 is detected, as in the fuel cell system 100B of the fourth embodiment described above. As described above, the exhaust valve 39Vr is opened, and the pressure in the air supply pipe 34 is reduced. By so doing, surging in the air compressor 32 can be quickly eliminated, and failure due to surging of the air compressor 32 can be suppressed in the fuel cell system.

F. Example 6:
FIG. 9 is an explanatory diagram showing a schematic configuration of a fuel cell system 100C as a sixth embodiment of the present invention. The configuration of the fuel cell system 100C of the sixth embodiment is substantially the same as that of the fuel cell system 100 of the fourth embodiment described above, and a detailed description of each part is omitted. In 100C of the sixth embodiment, a vibration sensor 33 is provided in the air compressor 32, and surging in the air compressor 32 is detected using the vibration sensor 33. Further, in the fuel cell system 100C of the sixth embodiment, the content of the operation control executed by the control unit 70C is different from that of the fourth embodiment. Hereinafter, operation control of the fuel cell system 100C of the sixth embodiment will be described.

  FIG. 10 is a flowchart showing a flow of operation control processing of the fuel cell system 100C of the sixth embodiment. This process is performed during operation of the fuel cell system 100C, that is, when hydrogen and air are respectively supplied to the anode and the cathode of the fuel cell stack 10 according to the output request to the fuel cell stack 10. This process is repeatedly executed by the CPU of the control unit 70C.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing through the air supply pipe 34 by the pressure sensor 37 and the flow rate sensor 38, respectively (step S600). Store the value in RAM. These detection values are used for opening / closing control of the exhaust valve 39Vr when surging occurs in the air compressor 32, as will be described later.

  Next, the CPU detects the vibration of the motor 32m included in the air compressor 32 by the vibration sensor 33, calculates the frequency f (step S610), and determines whether the frequency f is less than a predetermined threshold fth. Is determined (step S620). When the frequency f is less than the threshold fth (step S620: YES), the CPU determines that surging has occurred in the air compressor 32, opens the exhaust valve 39Vr (step S630), and supplies air. The pressure in the pipe 34 is reduced. In the present embodiment, the vibration sensor 33 and the control unit 70C correspond to a surging detection unit in the present invention.

  In the present embodiment as well, when surging occurs in the air compressor 32, that is, when surging in the air compressor 32 is detected as the opening degree and the valve opening time of the exhaust valve 39Vr at this time, The values specified in advance based on the pressure P in the supply pipe 34 and the flow rate Fr of the air flowing in the air supply pipe 34 are used. These values vary depending on the air supply condition by the air compressor 32, that is, the operating condition of the air compressor 32, and are set within a range in which surging in the air compressor 32 can be eliminated. Also in this embodiment, the relationship between the pressure P in the air supply pipe 34, the flow rate Fr of the air flowing through the air supply pipe 34, the opening degree of the exhaust valve 39Vr to be set, and the valve opening time is recorded. It is assumed that the map is stored in the ROM in advance.

  In step S620, when the vibration frequency f of the motor 32m included in the air compressor 32 is equal to or higher than the threshold value fth (step S620: NO), the CPU determines that surging has not occurred in the air compressor 32. Then, the operation control process described above is terminated, and the process returns to step S600.

  The fuel cell system of the sixth embodiment described above also eliminates the surging when the occurrence of surging in the air compressor 32 is detected, as in the fuel cell system 100B of the fourth embodiment described above. As described above, the exhaust valve 39Vr is opened, and the pressure in the air supply pipe 34 is reduced. By so doing, surging in the air compressor 32 can be quickly eliminated, and failure due to surging of the air compressor 32 can be suppressed in the fuel cell system.

G. Seventh embodiment:
The configuration of the fuel cell system of the seventh embodiment is the same as that of the fuel cell system 100 of the first embodiment described above, and detailed description of each part is omitted. In the fuel cell system of the seventh embodiment, the content of the operation control performed by the control unit 70 is different from that of the first embodiment. In the fuel cell systems of the first to sixth embodiments described above, when surging is detected in the air compressor 32, the operation control for eliminating this surging is performed. In the embodiment, operation control for avoiding surging in the air compressor 32 is performed in advance. Hereinafter, operation control of the fuel cell system of the seventh embodiment will be described.

  FIG. 11 is a flowchart showing a flow of operation control processing of the fuel cell system of the seventh embodiment. This process is performed during operation of the fuel cell system, that is, when hydrogen and air are respectively supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10. This process is repeatedly executed by the CPU of the control unit 70.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing in the air supply pipe 34 by the pressure sensor 37 and the flow rate sensor 38, respectively (step S700). Based on the value, the rotational speed Rs of the motor 32m where surging occurs in the air compressor 32 is predicted (step S710). Note that the rotational speed Rs of the motor 32m in which surging occurs in the air compressor 32 changes according to the pressure P and the flow rate Fr. In this embodiment, the rotational speed Rs is Rs1 ≦ Rs ≦ Rs2 (Rs1: The lower limit value and Rs2: the upper limit value).

  Next, the CPU determines whether or not the rotational speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is Rs1 ≦ R ≦ Rs2 (step S720). When the rotational speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is Rs1 ≦ R ≦ Rs2 (step S720: YES), the CPU sets the rotational speed of the motor 32m to the fuel cell stack 10. Assuming that the rotation speed R corresponds to the output request, it is determined that surging occurs in the air compressor 32, and surging occurs in the air compressor 32 regardless of the output request to the fuel cell stack 10 regardless of the output request to the fuel cell stack 10. Set the rotation speed not to be used. In this embodiment, the rotation speed R of the motor 32m is set to a value satisfying R <Rs1 (excluding 0 rotation / minute). The rotation speed R of the motor 32m may be a value that satisfies R> Rs2.

  In step S720, when the rotational speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is not Rs1 ≦ R ≦ Rs2 (step S720: NO), the CPU determines the rotational speed of the motor 32m as the fuel cell. Even if the rotation speed R is determined in response to the output request to the stack 10, it is determined that surging does not occur in the air compressor 32, the operation control process described above is terminated, and the process returns to step S700.

  According to the fuel cell system of the seventh embodiment described above, when the occurrence of surging in the air compressor 32 is predicted, the air compressor is avoided so as to avoid the surging regardless of the output request to the fuel cell stack 10. The rotational speed of the motor 32m included in the motor 32 is reduced to a predetermined rotational speed. By doing so, in the fuel cell system, failure due to surging of the air compressor 32 can be prevented.

H. Example 8:
The configuration of the fuel cell system of the eighth embodiment is the same as that of the fuel cell system 100B of the fourth embodiment described above, and a detailed description of each part is omitted. In the fuel cell system of the eighth embodiment, the content of the operation control executed by the control unit 70B is different from that of the fourth embodiment. Also in this embodiment, similarly to the seventh embodiment described above, operation control for avoiding surging in the air compressor 32 is performed in advance. Hereinafter, operation control of the fuel cell system of the eighth embodiment will be described.

  FIG. 12 is a flowchart showing a flow of operation control processing of the fuel cell system of the eighth embodiment. This process is performed during operation of the fuel cell system, that is, when hydrogen and air are respectively supplied to the anode and the cathode of the fuel cell stack 10 in response to the output request to the fuel cell stack 10. This process is repeatedly executed by the CPU of the control unit 70B.

  First, the CPU detects the pressure P in the air supply pipe 34 and the flow rate Fr of air flowing through the air supply pipe 34 by the pressure sensor 37 and the flow sensor 38, respectively (step S800). Based on the value, the rotational speed Rs of the motor 32m where surging occurs in the air compressor 32 is predicted (step S810). Note that the rotational speed Rs of the motor 32m in which surging occurs in the air compressor 32 changes according to the pressure P and the flow rate Fr. Also in this embodiment, the rotational speed Rs is Rs1 ≦ Rs ≦ Rs2 (Rs1 : Lower limit value, Rs2: upper limit value).

  Next, the CPU determines whether or not the rotational speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is Rs1 ≦ R ≦ Rs2 (step S820). When the rotation speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is Rs1 ≦ R ≦ Rs2 (step S820: YES), the CPU sets the rotation speed of the motor 32m to the fuel cell stack 10. Assuming that the rotation speed R corresponds to the output request, it is determined that surging occurs in the air compressor 32, the exhaust valve 39Vr is opened (step S830), and the pressure in the air supply pipe 34 is reduced. The opening of the exhaust valve 39Vr and the valve opening time at this time are such that the pressure in the air supply pipe 34 is the air pressure even when the rotation speed of the motor 32m is set to the rotation speed R corresponding to the output request to the fuel cell stack 10. Each is set within a range where the pressure is such that no surging occurs in the compressor 32.

  In step S720, when the rotational speed R of the motor 32m corresponding to the output request to the fuel cell stack 10 is not Rs1 ≦ R ≦ Rs2 (step S720: NO), the CPU determines the rotational speed of the motor 32m as the fuel cell. Even if the rotation speed R is determined in response to the output request to the stack 10, it is determined that surging does not occur in the air compressor 32, the operation control process described above is terminated, and the process returns to step S700.

  According to the fuel cell system of the eighth embodiment described above, when the occurrence of surging in the air compressor 32 is predicted, the exhaust valve 39Vr is opened so as to avoid the surging, and the air supply piping 34 Reduce the pressure inside. By doing so, in the fuel cell system, failure due to surging of the air compressor 32 can be prevented.

I. Variations:
As mentioned above, although several embodiment of this invention was described, this invention is not limited to such embodiment at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is. For example, the following modifications are possible.

I1. Modification 1:
In the first to third embodiments, in the operation control process, when surging in the air compressor 32 is detected, the rotation speed of the motor 32m is reduced to a predetermined rotation speed defined in advance. However, the present invention is not limited to this.

  FIG. 13 is a flowchart showing a flow of operation control processing as a modification of the first embodiment.

  First, the CPU detects the pressure P in the air supply pipe 34 by the pressure sensor 37 (step S100a), and stores the detected value in the RAM. As will be described later, this detected value is used to determine whether surging has occurred in the air compressor 32.

  Next, the CPU calculates a change rate ΔP of the pressure P in the air supply pipe 34 (step S110), and determines whether or not the absolute value | ΔP | of the change rate of the pressure P is larger than a predetermined threshold value Pth. Judgment is made (step S120). When the absolute value | ΔP | of the rate of change of the pressure P is equal to or less than the predetermined threshold value Pth (step S120: NO), the CPU determines that surging has not occurred in the air compressor 32 and operates. The control process ends, and the process returns to step S100a.

  On the other hand, when the absolute value | ΔP | of the rate of change of the pressure P is larger than the threshold value Pth (step S120: YES), the CPU determines that surging has occurred in the air compressor 32, and the fuel Regardless of the output request to the battery stack 10, the rotational speed of the motor 32m provided in the air compressor 32 is reduced (step S130a). At this time, the number of rotations to be reduced can be arbitrarily set.

  Then, the CPU again detects the pressure P in the air supply pipe 34 by the pressure sensor 37 (step S140), calculates the change rate ΔP of the pressure P (step S150), and the absolute value of the change rate of the pressure P. It is determined whether or not | ΔP | is larger than a predetermined threshold value Pth (step S160). When the absolute value | ΔP | of the change rate of the pressure P is equal to or less than the threshold value Pth (step S160: NO), the CPU determines that the surging in the air compressor 32 has been eliminated, and the above-described operation control. The process ends, and the process returns to step S100a.

  In step S160, when the absolute value | ΔP | of the rate of change of the pressure P is larger than the threshold value Pth (step S160: YES), the CPU determines that surging in the air compressor 32 has not been eliminated. Returning to step S130a, the operation control process described above is continued.

  FIG. 14 is a flowchart showing a flow of operation control processing as a modification of the second embodiment.

  First, the CPU detects the flow rate Fr of air flowing through the air supply pipe 34 by the flow rate sensor 38 (step S200a), and stores the detected value in the RAM. As will be described later, this detected value is used to determine whether surging has occurred in the air compressor 32.

  Next, the CPU calculates a change rate ΔFr of the flow rate Fr of the air flowing in the air supply pipe 34 (step S210), and whether the absolute value | ΔFr | of the change rate of the flow rate Fr is greater than a predetermined threshold value Frth. It is determined whether or not (step S220). When the absolute value | ΔFr | of the change rate of the flow rate Fr is equal to or less than the threshold value Frth (step S220: NO), the CPU determines that surging has not occurred in the air compressor 32, and operates the operation control process. Is finished, and the process returns to step S200a.

  On the other hand, when the absolute value | ΔFr | of the change rate of the flow rate Fr is larger than the threshold value Frth (step S220: YES), the CPU determines that surging has occurred in the air compressor 32, and the fuel Regardless of the output request to the battery stack 10, the rotational speed of the motor 32m provided in the air compressor 32 is reduced (step S230a). At this time, the number of rotations to be reduced can be arbitrarily set.

  The CPU again detects the flow rate Fr of the air flowing through the air supply pipe 34 by the flow rate sensor 38 (step S240), calculates the change rate ΔFr of the flow rate Fr (step S250), and changes the flow rate Fr. It is determined whether or not the absolute value | ΔFr | is greater than a predetermined threshold value Frth (step S260). If the absolute value | ΔFr | of the change rate of the flow rate Fr is equal to or less than the threshold value Frth (step S260: NO), the CPU determines that surging in the air compressor 32 has been eliminated, and performs the operation control process. End and return to step S200a.

  If the absolute value | ΔFr | of the change rate of the flow rate Fr is larger than the threshold value Frth in step S260 (step S260: YES), the CPU determines that surging in the air compressor 32 has not been eliminated. Returning to Step S230a, the operation control process described above is continued.

  FIG. 15 is a flowchart showing a flow of operation control processing as a modification of the third embodiment.

  First, the CPU detects vibration of the motor 32m included in the air compressor 32 by the vibration sensor 33, calculates the frequency f (step S310), and determines whether the frequency f is less than a predetermined threshold fth. Judgment is made (step S320). If the frequency f is greater than or equal to the predetermined threshold fth (step S320: NO), the CPU determines that surging has not occurred in the air compressor 32, ends the operation control process, and proceeds to step S310. Return.

  On the other hand, when the frequency f is less than the threshold value fth (step S320: YES), the CPU determines that surging has occurred in the air compressor 32, regardless of the output request to the fuel cell stack 10. Then, the rotational speed of the motor 32m provided in the air compressor 32 is reduced (step S330a). At this time, the number of rotations to be reduced can be arbitrarily set.

  Then, the CPU again detects the vibration of the motor 32m included in the air compressor 32 by the vibration sensor 33, calculates the frequency f (step S340), and determines whether the frequency f is less than the predetermined threshold fth. Is determined (step S350). If the frequency f is greater than or equal to the predetermined threshold fth (step S350: NO), the CPU determines that surging has been eliminated in the air compressor 32, ends the operation control process, and returns to step S310. .

  In step S350, when the frequency f is less than the threshold value fth (step S350: NO), the CPU determines that surging in the air compressor 32 has not been eliminated, and returns to step S330a to perform the above-described operation. Continue the control process.

  Also by the operation control process of the fuel cell system as the modified example described above, the failure due to the surging of the air compressor 32 can be suppressed as in the fuel cell systems of the first to third examples described above. it can.

I2. Modification 2:
In the first to third embodiments and the first modification, when the surging in the air compressor 32 is detected in the operation control process of the fuel cell system, the rotational speed of the motor 32m is decreased. However, it may be increased.

I3. Modification 3:
In the fourth to sixth embodiments and the eighth embodiment, the opening degree and the valve opening time of the exhaust valve 39Vr are controlled in the operation control process of the fuel cell system. It suffices to control at least one of them.

I4. Modification 4:
In the fuel cell system 100B shown in FIG. 6 and the fuel cell system 100C shown in FIG. 9, the exhaust pipe 39 branches from a portion between the pressure sensor 37 and the fuel cell stack 10 in the air supply pipe 34. However, the present invention is not limited to this.

I5. Modification 5:
In the above embodiment, the air compressor 32 is a turbo type air compressor. However, the present invention is not limited to this, and other types of air compressors may be applied.

I6. Modification 6:
In the above embodiment, the fuel cell system is mounted on an electric vehicle. However, the present invention is not limited to this, and may be, for example, a stationary fuel cell system. However, in the in-vehicle fuel cell system, since the output request for the fuel cell stack 10 changes abruptly according to the accelerator operation of the driver of the vehicle, the fuel that the output request for the fuel cell stack 10 hardly changes abruptly. Surging is likely to occur compared to battery systems. Therefore, it is particularly preferable to use the above-described fuel cell system for in-vehicle use.

I7. Modification 7:
In the above embodiment and the modification, the pressure in the air supply pipe 34 is reduced by reducing the rotational speed of the motor 32m provided in the air compressor 32 or by opening the exhaust valve 39Vr. Alternatively, by increasing the rotation speed of the motor 32m provided in the air compressor 32, the pressure in the air supply pipe 34 is increased, and surging in the air compressor 32 is eliminated or avoided. The present invention is not limited to this. In general, the present invention eliminates or avoids surging in the air compressor 32 by controlling the pressure in the air supply pipe 34, and the means in the air supply pipe 34 by means other than those described above. By controlling the pressure, surging in the air compressor 32 may be eliminated or avoided.

It is explanatory drawing which shows schematic structure of the fuel cell system 100 as 1st Example of this invention. 3 is a flowchart showing a flow of operation control processing of the fuel cell system 100 of the first embodiment. It is a flowchart which shows the flow of the operation control process of the fuel cell system of 2nd Example. It is explanatory drawing which shows schematic structure of 100 A of fuel cell systems as 3rd Example of this invention. It is a flowchart which shows the flow of the operation control process of 100 A of fuel cell systems of 3rd Example. It is explanatory drawing which shows schematic structure of the fuel cell system 100B as 4th Example of this invention. It is a flowchart which shows the flow of the operation control process of the fuel cell system 100B of 4th Example. It is a flowchart which shows the flow of the operation control process of the fuel cell system of 5th Example. It is explanatory drawing which shows schematic structure of 100 C of fuel cell systems as 6th Example of this invention. It is a flowchart which shows the flow of the operation control process of 100 C of fuel cell systems of 6th Example. It is a flowchart which shows the flow of the operation control process of the fuel cell system of 7th Example. It is a flowchart which shows the flow of the operation control process of the fuel cell system of 8th Example. It is a flowchart which shows the flow of the operation control process as a modification of 1st Example. It is a flowchart which shows the flow of the operation control process as a modification of 2nd Example. It is a flowchart which shows the flow of the operation control process as a modification of 3rd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,100A, 100B, 100C ... Fuel cell system 10 ... Fuel cell stack 20 ... Hydrogen tank 21 ... Shut valve 22 ... Regulator 23 ... Hydrogen supply piping 24 ... Piping 25 ... Gas-liquid separator 26 ... Circulation piping 27 ... Circulation pump 28 ... Piping 29 ... Purge valve 30 ... Air cleaner 32 ... Air compressor 32m ... Motor 33 ... Vibration sensor 34 ... Air supply pipe 35 ... Air pressure regulating valve 36 ... Piping 37 ... Pressure sensor 38 ... Flow sensor 39 ... Exhaust pipe 39Vr ... Exhaust valve 40 ... Radiator 41 ... Circulating pump 42 ... Piping 43 ... Bypass piping 44 ... Three-way valve 45 ... Ion exchanger 46 ... Piping 50 ... Diluter 60 ... Piping 70, 70A, 70B, 70C ... Control unit

Claims (18)

A fuel cell system,
A fuel cell that generates electricity by an electrochemical reaction between hydrogen and oxygen;
An air supply pipe for supplying the oxygen-containing air to the cathode of the fuel cell;
An air compressor connected to the air supply pipe, for compressing the air and flowing it through the air supply pipe;
In response to an output request for the fuel cell, a motor control unit that controls the number of revolutions of a motor included in the air compressor;
A surging detector that detects the occurrence of surging in the air compressor;
A pressure control unit for controlling the pressure in the air supply pipe so as to eliminate the surging when the surging is detected by the surging detection unit;
A fuel cell system comprising: The fuel cell system according to claim 1, wherein
The pressure control unit controls the pressure in the air supply pipe by controlling the number of revolutions of the motor regardless of the output request when the occurrence of the surging is detected by the surging detection unit. A fuel cell system. The fuel cell system according to claim 2, wherein
The pressure control unit, when the occurrence of surging is detected by the surging detection unit, flows in the air supply pipe when the occurrence of surging is detected, and flows in the air supply pipe The flow rate of air is acquired, and the number of rotations of the motor is reduced to a number of rotations less than a predetermined number of rotations defined based on the pressure and the flow rate and excluding 0 rotations / minute. , Fuel cell system. The fuel cell system according to claim 2, wherein
When the occurrence of surging is detected by the surging detection unit, the pressure control unit flows through the pressure in the air supply pipe when the occurrence of surging is detected, and the air supply pipe A fuel cell system that acquires a flow rate of air and increases a rotational speed of the motor to a rotational speed higher than a predetermined rotational speed defined based on the pressure and the flow rate. The fuel cell system according to claim 1, wherein
The pressure controller is
An exhaust pipe that is branched from the air supply pipe and connected to exhaust the air flowing in the air supply pipe to the outside;
An exhaust valve disposed in the exhaust pipe,
A fuel cell system, wherein when the occurrence of surging is detected by the surging detection unit, the pressure in the air supply pipe is controlled by performing opening / closing control of the exhaust valve. The fuel cell system according to claim 5, wherein
The exhaust valve opening / closing control includes a control of at least one of an opening degree of the exhaust valve and a valve opening time. The fuel cell system according to claim 6, wherein
When the occurrence of surging is detected by the surging detection unit, the pressure control unit flows through the pressure in the air supply pipe when the occurrence of surging is detected, and the air supply pipe The flow rate of air is acquired, and based on the pressure and the flow rate, at least one of the opening degree and the valve opening time of the exhaust valve is determined based on the pressure and the flow rate. The fuel cell system to set to the value. A fuel cell system according to any one of claims 5 to 7,
As the surging detection unit, comprising a pressure sensor for detecting the pressure in the air supply pipe,
The said exhaust pipe is a fuel cell system connected to the site | part between the said pressure sensor and the said fuel cell in the said air supply piping. The fuel cell system according to any one of claims 1 to 7,
The surging detection unit
A pressure sensor for detecting the pressure in the air supply pipe;
A flow rate sensor for detecting a flow rate of air flowing in the air supply pipe;
A vibration sensor for detecting vibration of the air compressor;
A fuel cell system comprising at least one of the above. A fuel cell system,
A fuel cell that generates electricity by an electrochemical reaction between hydrogen and oxygen;
An air supply pipe for supplying the oxygen-containing air to the cathode of the fuel cell;
An air compressor connected to the air supply pipe, for compressing the air and flowing it through the air supply pipe;
In response to an output request for the fuel cell, a control unit that controls the number of revolutions of a motor included in the air compressor;
The pressure in the air supply pipe and the flow rate of the air flowing in the air supply pipe are acquired, and the air supply pipe is configured to avoid surging in the air compressor based on the pressure and the flow rate. A pressure control unit for controlling the pressure inside,
A fuel cell system comprising: The fuel cell system according to claim 10, wherein
The pressure control unit determines whether the rotation speed of the motor corresponding to the output request is a rotation speed at which the surging occurs in the air compressor, and the rotation speed of the motor corresponding to the output request. However, when it is determined that the surging occurs in the air compressor, the pressure in the air supply pipe is controlled by controlling the rotation speed of the motor regardless of the output request. Fuel cell system. The fuel cell system according to claim 11, wherein
The pressure control unit determines that the rotation speed of the motor corresponding to the output request is the rotation speed at which the surging occurs in the air compressor, based on the pressure and the flow rate, A fuel cell system, wherein the number of rotations of the motor is reduced to a number of rotations less than a predetermined number of rotations defined based on the pressure and the flow rate and excluding 0 rotations / minute. The fuel cell system according to claim 11, wherein
The pressure control unit determines that the rotation speed of the motor corresponding to the output request is a rotation speed at which the surging occurs in the air compressor, based on the pressure and the flow rate, A fuel cell system that increases the rotational speed of a motor to a rotational speed higher than a predetermined rotational speed defined based on the pressure and the flow rate. The fuel cell system according to claim 10, wherein
The pressure controller is
An exhaust pipe that is branched from the air supply pipe and connected to exhaust the air flowing in the air supply pipe to the outside;
An exhaust valve disposed in the exhaust pipe,
When it is determined that the rotation speed of the motor corresponding to the output request is the rotation speed at which the surging occurs in the air compressor, the pressure in the air supply pipe is controlled by performing opening / closing control of the exhaust valve. Control the fuel cell system. The fuel cell system according to claim 14, wherein
The exhaust valve opening / closing control includes a control of at least one of an opening degree of the exhaust valve and a valve opening time. The fuel cell system according to claim 15, wherein
When the pressure control unit determines that the rotation speed of the motor corresponding to the output request is the rotation speed at which the surging occurs in the air compressor, the opening degree of the exhaust valve and the valve opening time A fuel cell system in which at least one of is set to a predetermined value defined based on the pressure and the flow rate. The fuel cell system according to any one of claims 1 to 16,
The fuel cell system, wherein the air compressor is a turbo type air compressor. The fuel cell system according to any one of claims 1 to 17,
The fuel cell system is an on-vehicle fuel cell system.

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