Fuel cell system

Abstract

To solve the problem of a fuel cell system in which accurate control of a flow quantity of cathode gas is impossible because of generation of a gap between an actual pressure loss and a pressure loss at the time of designing.SOLUTION: A fuel cell system comprises a system suction part to which a suction pipe is connected, a system exhaust part to which an exhaust pipe is connected, a fuel cell stack, an atmospheric pressure sensor, an air compressor, an air flow meter, a pressure sensor, and a controller. The controller actuates the air compressor and creates an exhaust pipe pressure loss map and a suction pipe pressure loss map in a state in which the suction pipe and the exhaust pipe are connected before power generation and refers to the exhaust pipe pressure loss map and the suction pipe pressure loss map on the basis of a target value of a stack flow quantity, determines an exhaust pipe pressure loss and a suction pipe pressure loss, determines the number of rotation for implementing the target value in a pressure ratio between inlet pressure and outlet pressure, and controls the air compressor using the determined number of rotation in power generation.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to fuel cell systems. [Background technology]

[0002] As described in Patent Document 1, a fuel cell system is connected to an intake line including an intake pipe that supplies cathode gas to a fuel cell stack, and an exhaust line including an exhaust pipe that discharges cathode gas from the fuel cell stack. The fuel cell system is equipped with an air compressor that supplies cathode gas to the fuel cell stack, and an intercooler that adjusts the temperature of the cathode gas. The outlet of the intercooler is connected to the inlet of the cathode flow path of the fuel cell stack. That is, the cathode gas is sucked in by the air compressor, and is supplied to the fuel cell stack via the intake line and the intercooler.

[0003] Patent Document 1 describes that the pressure at the outlet of the intercooler is affected by pressure loss in the intake line and from the intake line to the intercooler. The pressure loss depends on the length of the pipe, the shape of the pipe, and the friction coefficient of the inner surface of the pipe. Therefore, the specifications of the pipes in the intake line and exhaust line affect the amount of cathode gas flowing into the fuel cell stack and the amount of cathode gas discharged from the fuel cell stack. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-126792 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors have developed a fuel cell system including a fuel cell stack, an air compressor, a control device, and the like. The inventors' fuel cell system does not include an intake line and an exhaust line and can be used universally. More specifically, the inventors' fuel cell system can be connected to intake lines and exhaust lines appropriate for passenger cars, trucks, ships, stationary power generation facilities, and the like. The inventors' fuel cell system used fixed values ​​for the pressure loss in the intake line and exhaust line.

[0006] However, pipe specifications vary depending on the product in which the fuel cell system is installed. This causes changes in the pressure loss in the intake and exhaust lines. As a result, there is a discrepancy between the actual pressure loss and the fixed value of the pressure loss at the time of design, making it difficult to accurately control the flow rate of the cathode gas, which has been an issue. [Means for solving the problem]

[0007] The present disclosure can be realized in the following forms.

[0008] (1) According to one aspect of the present disclosure, there is provided a fuel cell system comprising: a system intake section through which cathode gas supplied to the fuel cell system flows and to which an intake pipe having an intake pipe pressure loss is connected; a system exhaust section through which cathode gas discharged from the fuel cell system flows and to which an exhaust pipe having an exhaust pipe pressure loss is connected; a fuel cell stack that generates electricity using the cathode gas supplied via the system intake section and discharges the cathode gas used for the electricity generation via the system exhaust section; an atmospheric pressure sensor that acquires atmospheric pressure; an air compressor that compresses the cathode gas flowing through the system intake section and can discharge the cathode gas to the fuel cell stack; an air flow meter that acquires an air flow meter flow rate that is the flow rate of the cathode gas taken into the air compressor; a pressure sensor that acquires an outlet pressure that is the pressure on the outlet side of the air compressor; and a control device that controls the fuel cell system, wherein the control device operates the air compressor at a plurality of mutually different air flow meter flow rates while the intake pipe and the exhaust pipe are connected to the fuel cell system prior to power generation in the fuel cell system. an exhaust pipe pressure loss map corresponding to the air flow meter flow rate based on the difference between the atmospheric pressure, which is the pressure of the cathode gas at the outlet of the exhaust pipe, and the outlet pressure; an intake pipe pressure loss map corresponding to the air flow meter flow rate based on the difference between a calculated value of an inlet pressure, which is the pressure on the inlet side of the air compressor, which is determined based on the outlet pressure and the rotational speed of the air compressor, and the atmospheric pressure, which is the pressure of the cathode gas at the inlet of the intake pipe; and, in power generation by the fuel cell system, referring to the exhaust pipe pressure loss map and the intake pipe pressure loss map based on a target value of a stack flow rate supplied to the fuel cell stack to achieve a target current, determine the exhaust pipe pressure loss at the target value and the intake pipe pressure loss at the target value; determine a rotational speed to achieve the target value at a pressure ratio between the inlet pressure, which is determined based on the difference between the atmospheric pressure and the intake pipe pressure loss at the target value, and an outlet pressure, which is determined based on the sum of the atmospheric pressure and the exhaust pipe pressure loss at the target value; and control the air compressor using the determined rotational speed. Fuel cell systems are installed in a variety of products, including passenger cars, trucks, ships, and stationary power generation facilities. The exhaust manifold pressure loss and intake manifold pressure loss vary depending on the product in which the fuel cell system is installed. By adopting this configuration, the fuel cell system determines the intake manifold pressure loss map and the exhaust manifold pressure loss map before generating power. This allows the fuel cell system to control the air compressor rotation speed while taking into account the intake manifold pressure loss and the exhaust manifold pressure loss during power generation. Therefore, the fuel cell system can more accurately control the flow rate of cathode gas circulating in the fuel cell stack than a configuration that uses fixed pressure losses regardless of the specifications of the intake manifold and exhaust manifold. (2) The fuel cell system of the above aspect may further include a first valve provided on the inlet side of the fuel cell stack for changing the flow rate of cathode gas supplied to the fuel cell stack, a second valve provided on the outlet side of the fuel cell stack for changing the flow rate of cathode gas discharged from the fuel cell stack, a bypass pipe connecting the inlet side of the first valve and the outlet side of the second valve, and a third valve for changing the flow rate of cathode gas flowing through the bypass pipe, and the control device may create the intake manifold pressure loss map and the intake manifold pressure loss map while the first valve and the second valve are closed and the third valve is open. By adopting this configuration, when determining the intake pipe pressure loss map and the exhaust pipe pressure loss map, the cathode gas does not flow through the fuel cell stack, which means that the fuel cell system can more accurately determine the pressure loss in the intake pipe and the exhaust pipe by excluding the pressure loss caused by the fuel cell stack. (3) In the fuel cell system of the above aspect, the air compressor may further include a bearing intake pipe that circulates a portion of the cathode gas discharged by the air compressor through a bearing of the air compressor and has a bearing intake pipe pressure loss as a pressure loss, and a bearing exhaust pipe that circulates the cathode gas that has circulated through the bearing to the system exhaust section and has a bearing exhaust pipe pressure loss as a pressure loss, and the control device may further, prior to power generation in the fuel cell system, create a flow rate map of stack flow rate corresponding to the air flow meter flow rate based on the intake pipe pressure loss, the exhaust pipe pressure loss, the bearing exhaust pipe pressure loss, the bearing intake pipe pressure loss, and the pressure loss of the fuel cell system while the air compressor is operating, and during power generation in the fuel cell system, determine the exhaust pipe pressure loss and the intake pipe pressure loss based on the target value and the flow rate map. In this configuration, the fuel cell system circulates cathode gas through the bearing of the air compressor. The air compressor bearing becomes hot due to the rotation of the motor while the air compressor is operating. This causes the shaft and bearing to weld together, changing the characteristics of the air compressor. Therefore, even if the control device performs control by referring to a predetermined intake manifold pressure loss map and exhaust manifold pressure loss map, the flow rate of cathode gas may deviate from the ideal value. The fuel cell system cools the bearing by flowing cathode gas through the air compressor bearing. Therefore, the fuel cell system can control the flow rate of cathode gas circulating in the fuel cell stack more accurately than a configuration in which the bearing is not cooled. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the characteristics of an air compressor. [Figure 3] FIG. 2 is a block diagram showing the configuration of a control device. [Figure 4] 4 is a flowchart showing a method for setting a fuel cell system. [Figure 5] FIG. 4 is an explanatory diagram showing a pressure loss map. [Figure 6] 10 is a flowchart showing a method for determining a map. DETAILED DESCRIPTION OF THE INVENTION

[0010] A. First embodiment: A-1. System configuration: FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system 1 according to a first embodiment. The fuel cell system 1 is mounted, for example, as a power source on passenger cars, trucks, ships, stationary power generation facilities, and the like. To receive a supply of cathode gas required for power generation, the fuel cell system 1 is connected to an intake pipe Li and an exhaust pipe Lo provided on the product on which the fuel cell system 1 is mounted. In FIG. 1, solid lines with arrows indicate piping. The arrows indicate the flow direction of the cathode gas. That is, the intake pipe Li on the lower left of FIG. 1 is upstream, and the exhaust pipe Lo on the lower right of FIG. 1 is downstream.

[0011] The intake pipe Li circulates the cathode gas to be supplied to the fuel cell system 1 (see the lower left part of FIG. 1). More specifically, the intake pipe Li is a pipe that connects the fuel cell system 1 to the atmosphere outside the product in which the fuel cell system 1 is installed. That is, the pressure at the inlet Lie of the intake pipe Li is atmospheric pressure Pa. The system intake section 10 to which the intake pipe Li is connected is controlled to be lower than atmospheric pressure Pa by an air compressor 60, which will be described later. Therefore, the cathode gas flows through the intake pipe Li and is supplied to the fuel cell system 1.

[0012] The intake pipe Li is connected to a system intake section 10 of the fuel cell system 1 via an air cleaner 100, which will be described later. In this specification, the intake pipe Li located upstream of the air cleaner 100 is referred to as a first intake pipe Li1. The intake pipe Li located downstream of the air cleaner 100 is referred to as a second intake pipe Li2.

[0013] The exhaust pipe Lo circulates the cathode gas discharged from the fuel cell system 1 (see the lower right part of FIG. 1). More specifically, the exhaust pipe Lo is connected to the system exhaust section 20 of the fuel cell system 1. That is, the exhaust pipe Lo is a pipe that connects the fuel cell system 1 to the atmosphere outside the product in which the fuel cell system 1 is installed. That is, the pressure at the outlet Loe of the exhaust pipe Lo is atmospheric pressure Pa. The pressure of the system exhaust section 20 to which the exhaust pipe Lo is connected is controlled by the air compressor 60 to be higher than atmospheric pressure Pa. Therefore, the cathode gas flows through the exhaust pipe Lo and is discharged from the fuel cell system 1.

[0014] The specifications of the intake pipe Li and the exhaust pipe Lo vary depending on the product in which the fuel cell system 1 is installed. Specifically, the specifications of the intake pipe Li and the exhaust pipe Lo include the length of the pipe, the shape of the pipe, and the friction coefficient of the inner surface of the pipe. In this specification, the pressure loss in the intake pipe Li is defined as the intake pipe pressure loss Di. The pressure loss in the exhaust pipe Lo is defined as the exhaust pipe pressure loss Do.

[0015] The fuel cell system 1 includes a system intake section 10, a system exhaust section 20, a fuel cell stack 30, a stack intake section 40, an atmospheric pressure sensor 50, an air compressor 60, an air flow meter 70, a pressure sensor 80, a control device 90, an air cleaner 100, a first valve 110, a second valve 120, a third valve 130, a bypass pipe 140, an intercooler 150, a first temperature sensor 160, a second temperature sensor 170, and a third temperature sensor 180.

[0016] 1, the components of the fuel cell system 1 other than the atmospheric pressure sensor 50, air flow meter 70, air cleaner 100, and first temperature sensor 160 are configured as one module M1 regardless of the positions of the intake pipe Li and exhaust pipe Lo. The atmospheric pressure sensor 50, air flow meter 70, air cleaner 100, and first temperature sensor 160 are illustrated separately from the module M1 because they are arranged according to the positions of the intake pipe Li and exhaust pipe Lo.

[0017] The fuel cell stack 30 is configured by stacking a plurality of unit cells, each of which can serve as a power generation element (see the upper part of Figure 1). Each unit cell is a so-called solid polymer fuel cell, and generates power by receiving a supply of hydrogen gas as an anode gas and air as a cathode gas. Each unit cell has a membrane electrode assembly in which electrodes are arranged on both sides of an ion-conductive polymer electrolyte membrane, and a pair of separators that sandwich the membrane electrode assembly. An anode flow path (not shown) through which hydrogen gas flows is formed between the membrane electrode assembly and the separator on the anode side. A cathode flow path 31 through which cathode gas flows is formed between the membrane electrode assembly and the separator on the cathode side. In Figure 1, only the cathode flow path 31 is shown to facilitate understanding of the technology.

[0018] In the fuel cell stack 30, a stack intake section 40 is connected to the inlet of the cathode flow path 31. In the fuel cell stack 30, a system exhaust section 20 is connected to the outlet of the cathode flow path 31. That is, the fuel cell stack 30 generates power using cathode gas supplied via the stack intake section 40. In the fuel cell stack 30, the cathode gas used for power generation is discharged via the system exhaust section 20. Therefore, for the cathode gas, the inlet of the cathode flow path 31 is the inlet side of the fuel cell stack 30, and the outlet of the cathode flow path 31 is the outlet side of the fuel cell stack 30. In this specification, the flow rate supplied to the fuel cell stack 30 is defined as a stack flow rate Qs.

[0019] The air cleaner 100 removes foreign matter from the cathode gas supplied to the fuel cell system 1. The air cleaner 100 is provided in the intake pipe Li. That is, the air cleaner 100 prevents foreign matter in the atmosphere from being mixed into the fuel cell system 1 together with the cathode gas.

[0020] An intake pipe Li is connected to the system intake section 10 (see the lower center of Figure 1). The intake pipe Li connected to the system intake section 10 is the second intake pipe Li2 located downstream of the air cleaner 100. In other words, the system intake section 10 is a pipe connecting the second intake pipe Li2 and the air compressor 60. The system intake section 10 circulates the cathode gas purified by the air cleaner 100 to the air compressor 60.

[0021] The atmospheric pressure sensor 50 acquires the atmospheric pressure Pa (see the lower left part of FIG. 1). By acquiring the atmospheric pressure Pa, the atmospheric pressure sensor 50 acquires the pressure of the cathode gas at the inlet Lie of the intake pipe Li. Furthermore, by acquiring the atmospheric pressure Pa, the atmospheric pressure sensor 50 acquires the pressure of the cathode gas at the outlet Loe of the exhaust pipe Lo. In other words, the atmospheric pressure sensor 50 acquires the pressure of the cathode gas upstream of the intake pipe Li and downstream of the exhaust pipe Lo. The atmospheric pressure sensor 50 sends information about the acquired atmospheric pressure Pa to the control device 90.

[0022] The air flow meter 70 acquires the air flow meter flow rate Qi, which is the flow rate of the cathode gas taken into the air compressor 60 (see the lower left part of FIG. 1). The air flow meter 70 is provided in the second intake pipe Li2 between the air cleaner 100 and the system intake section 10. As shown in FIG. 1, the cathode gas flowing through the system intake section 10 flows to the air compressor 60. The air flow meter 70 sends information about the acquired air flow meter flow rate Qi to the control device 90.

[0023] The first temperature sensor 160 acquires the temperature of the cathode gas taken into the air compressor 60. The first temperature sensor 160 sends the acquired temperature to the control device 90.

[0024] The air compressor 60 compresses the cathode gas flowing through the system intake section 10 and discharges the cathode gas to the fuel cell stack 30 (see the lower center part of FIG. 1). Specifically, the air compressor 60 is a two-stage boost turbo compressor. The air compressor 60 includes a first compressor 61, a second compressor 62, a motor 63, a bearing (not shown), a relay pipe 64, a bearing intake pipe 65, and a bearing exhaust pipe 66.

[0025] The first compressor 61 includes a first impeller (not shown) and a first impeller housing (not shown) that houses the first impeller. The first impeller is connected to one end of a rotary shaft 63s of a motor 63 and is rotated by the motor 63. The first impeller housing is connected to the system intake section 10 and a relay pipe 64. That is, the first compressor 61 draws in cathode gas from the system intake section 10 as the first impeller rotates. Furthermore, the first compressor 61 compresses the cathode gas within the first impeller housing. Furthermore, the first compressor 61 discharges the compressed cathode gas to the relay pipe 64.

[0026] The second compressor 62 includes a second impeller (not shown) and a second impeller housing (not shown) that houses the second impeller. The second impeller is connected to the other end of the rotary shaft 63s of the motor 63 and is rotated by the motor 63. The second impeller housing is connected to the relay pipe 64 and the stack intake section 40. That is, the second compressor 62 draws in cathode gas from the relay pipe 64 as the second impeller rotates. Furthermore, the second compressor 62 compresses the cathode gas within the second impeller housing. Furthermore, the second compressor 62 discharges the compressed cathode gas to the stack intake section 40.

[0027] That is, the cathode gas is taken in from the side of the first compressor 61 and discharged from the side of the second compressor 62. Therefore, for the cathode gas, the inlet of the first compressor 61 is the inlet side of the air compressor 60, and the outlet of the second compressor 62 is the outlet side of the air compressor 60. In this specification, the pressure of the cathode gas on the inlet side of the air compressor 60 is defined as the inlet pressure Pci. The pressure of the cathode gas on the outlet side of the air compressor 60 is defined as the outlet pressure Pco. The ratio of the outlet pressure Pco to the inlet pressure Pci obtained by equation (1) is defined as the pressure ratio R. R = Pco / Pci … (1)

[0028] It should be noted that the outlet pressure Pco is not the pressure at the outlet of the second compressor 62. The outlet pressure Pco is acquired by a pressure sensor 80, which will be described later. In the cathode gas flow path, the intercooler 150, the bearing intake pipe 65, and the first stack intake section 41 are provided between the pressure sensor 80 and the air compressor 60. For this reason, the outlet pressure Pco is lower than the pressure at the outlet of the second compressor 62 due to pressure losses caused by the intercooler 150, the bearing intake pipe 65, and the first stack intake section 41.

[0029] The motor 63 rotates the first impeller and the second impeller. The motor 63 is located between the first impeller and the second impeller, and rotates the first impeller and the second impeller via a rotation shaft 63s. The motor 63 rotates at a rotation speed n per unit time in accordance with a command from the control device 90.

[0030] Fig. 2 is an explanatory diagram showing the characteristics of the air compressor 60. The air compressor 60 has a relationship between the pressure ratio R, the air flow meter flow rate Qi, and the rotation speed n, as shown in Fig. 2. In other words, the relationship between the pressure ratio R and the air flow meter flow rate Qi varies depending on the rotation speed n. A control device 90, which will be described later, controls the rotation speed n based on the characteristics of the air compressor 60.

[0031] The bearing rotatably supports the rotary shaft 63s of the motor 63. Specifically, the bearing is an air bearing. A bearing intake pipe 65 and a bearing exhaust pipe 66 are connected to the bearing portion of the air compressor 60 (see the lower center of FIG. 1). That is, a portion of the cathode gas discharged by the air compressor 60 flows into the bearing. As a result, the bearing is cooled by the cathode gas.

[0032] The bearings become hot due to the rotation of the motor 63 while the air compressor 60 is in operation. Welding between the rotating shaft 63s and the bearings changes the characteristics of the air compressor 60. Therefore, even if the control device 90 performs control by referring to a predetermined intake pipe pressure loss map and an exhaust pipe pressure loss map, the cathode gas flow rate may deviate from the ideal value. The intake pipe pressure loss map and the exhaust pipe pressure loss map will be described later. The fuel cell system 1 of this embodiment cools the bearings of the air compressor 60 by flowing cathode gas through them. Therefore, the fuel cell system 1 of this embodiment can more accurately determine the pressure loss in the intake pipe Li and the exhaust pipe Lo than a configuration in which the bearings are not cooled. In this specification, the flow rate flowing through the bearings is defined as the bearing cooling flow rate Qb. The pressure loss in the bearing portion is defined as the bearing pressure loss Dtb.

[0033] The bearing intake pipe 65 circulates a portion of the cathode gas discharged by the air compressor 60 to the bearing of the air compressor 60. More specifically, the bearing intake pipe 65 is a pipe that connects the first stack intake section 41 and the bearing portion of the air compressor 60. In this specification, the pressure loss in the bearing intake pipe 65 is defined as the bearing intake pipe pressure loss Dtbi.

[0034] The bearing exhaust pipe 66 allows the cathode gas that has circulated through the bearing to circulate to the system exhaust section 20. More specifically, the bearing exhaust pipe 66 is a pipe that connects the bearing portion of the air compressor 60 and the system exhaust section 20. In this specification, the pressure loss in the bearing exhaust pipe 66 is defined as the bearing exhaust pipe pressure loss Dtbo.

[0035] The stack intake section 40 distributes the cathode gas discharged from the air compressor 60 to the fuel cell stack 30. The stack intake section 40 is composed of a first stack intake section 41, a second stack intake section 42, and a third stack intake section 43.

[0036] The first stack intake section 41 is a pipe connecting the second compressor 62 and the intercooler 150 (see the lower center of Figure 1). The first stack intake section 41 is also connected to the bearing intake pipe 65. Therefore, a portion of the cathode gas discharged from the air compressor 60 flows into the bearing intake pipe 65. The second stack intake section 42 is a pipe connecting the intercooler 150 and the first valve 110 (see the middle center of Figure 1). The second stack intake section 42 is also connected to a bypass pipe 140 in which the third valve 130 is provided. Therefore, depending on the open / close states of the first valve 110 and the third valve 130, the cathode gas in the second stack intake section 42 flows into the bypass pipe 140. The third stack intake section 43 is a pipe connecting the first valve 110 and the cathode flow path 31 (see the upper center of Figure 1).

[0037] The intercooler 150 cools the cathode gas discharged from the air compressor 60 (see the middle center of FIG. 1). The temperature of the cathode gas increases when it is compressed by the air compressor 60. High-temperature cathode gas, for example, dries out the electrolyte membrane of the fuel cell stack 30, accelerating deterioration of the fuel cell stack 30. The intercooler 150 cools the cathode gas using cooling water supplied from a cooling system (not shown). The intercooler 150 cools the cathode gas under the control of the control device 90 based on the temperatures of the cathode gas acquired by the first temperature sensor 160 to the third temperature sensor 180.

[0038] The second temperature sensor 170 acquires the temperature of the cathode gas discharged from the intercooler 150 (see the center of the middle row in FIG. 1). The second temperature sensor 170 sends the acquired temperature to the control device 90.

[0039] The pressure sensor 80 acquires the outlet pressure Pco, which is the pressure on the outlet side of the air compressor 60 (see the middle center of FIG. 1 ). The pressure sensor 80 is provided in the second stack intake section 42. That is, the pressure sensor 80 is provided downstream of the intercooler 150 and upstream of the first valve 110 and the third valve 130. That is, the pressure sensor 80 acquires the pressure of the cathode gas cooled by the intercooler 150 as the outlet pressure Pco. The pressure sensor 80 sends the acquired outlet pressure Pco to the control device 90.

[0040] The first valve 110 is provided on the inlet side of the fuel cell stack 30, and changes the flow rate of the cathode gas supplied to the fuel cell stack 30 (see the middle center part of FIG. 1). More specifically, the first valve 110 is provided downstream of the intercooler 150 and upstream of the cathode flow path 31. The first valve 110 opens and closes in response to commands from the control device 90. The first valve 110 is also referred to as a sealing valve 110.

[0041] An exhaust pipe Lo is connected to the system exhaust section 20 (see the right part of FIG. 1). The system exhaust section 20 includes a first system exhaust section 21 and a second system exhaust section 22. The first system exhaust section 21 is a pipe connecting the cathode flow path 31 and the second valve 120. The second system exhaust section 22 is a pipe connecting the second valve 120 and the exhaust pipe Lo. That is, the system intake section 10 causes the cathode gas discharged from the cathode flow path 31 to flow into the exhaust pipe Lo. The second system exhaust section 22 is also connected to the bypass pipe 140. Therefore, the cathode gas discharged from the bypass pipe 140 flows into the exhaust pipe Lo via the second system exhaust section 22.

[0042] The third temperature sensor 180 acquires the temperature of the cathode gas discharged from the cathode flow channel 31 (see the upper right part of FIG. 1). The third temperature sensor 180 sends the acquired temperature to the control device 90.

[0043] The second valve 120 is provided on the outlet side of the fuel cell stack 30 and changes the flow rate of the cathode gas discharged from the fuel cell stack 30 (see the middle right part of FIG. 1). The second valve 120 is provided in the system exhaust section 20. The second valve 120 opens and closes in response to commands from the control device 90. The second valve 120 is also called a pressure regulating valve 120.

[0044] The bypass pipe 140 connects the inlet side of the first valve 110 and the outlet side of the second valve 120. More specifically, the bypass pipe 140 is a pipe that connects the second stack intake section 42 and the second system exhaust section 22.

[0045] The third valve 130 changes the flow rate of the cathode gas flowing through the bypass pipe 140. That is, the third valve 130 is provided in the bypass pipe 140. The third valve 130 opens and closes in response to commands from the control device 90. The third valve 130 is also called a flow dividing valve 130.

[0046] In this specification, the total pressure loss of the system intake section 10, stack intake section 40, system exhaust section 20, and cathode flow path 31 is defined as the pressure loss of the fuel cell system 1, and is referred to as the system pressure loss Dtf.

[0047] FIG. 3 is a block diagram showing the configuration of the control device 90. The control device 90 is configured as a logic circuit centered around a microcomputer. More specifically, the control device 90 includes a CPU 91, a ROM 92, and a RAM 93. The CPU 91 executes a preset control program. The ROM 92 stores in advance control programs and control data required for the CPU 91 to execute various arithmetic processes. The RAM 93 temporarily reads and writes various data required for the CPU 91 to execute various arithmetic processes. The functions of the control device 90 will be described below.

[0048] A-2. How to set up a fuel cell system: 4 is a flowchart showing a method for setting up the fuel cell system 1. The following describes the setting method up to the point where power generation is performed by the fuel cell system 1. As mentioned above, the fuel cell system 1 is mounted on a passenger car, truck, ship, stationary power generation facility, or the like.

[0049] 4, the fuel cell system 1 is connected to an intake pipe Li and an exhaust pipe Lo of a product in which the fuel cell system 1 is to be installed. Specifically, the user connects the intake pipe Li to the system intake section 10 and the exhaust pipe Lo to the system exhaust section 20. Furthermore, the user also installs an atmospheric pressure sensor 50, an air flow meter 70, an air cleaner 100, and a first temperature sensor 160.

[0050] FIG. 5 is an explanatory diagram showing a pressure loss map. In step S2 of FIG. 4, the control device 90 creates a pressure loss map. Specifically, the pressure loss map is information shown in FIG. 5. The pressure loss map is a general term for an intake pipe pressure loss map and an exhaust pipe pressure loss map. The intake pipe pressure loss map shows the relationship between the air flow meter flow rate Qi and the intake pipe pressure loss Di. The exhaust pipe pressure loss map shows the relationship between the air flow meter flow rate Qi and the exhaust pipe pressure loss Do. The creation of the pressure loss map will be explained in detail later.

[0051] Furthermore, the control device 90 creates a flow rate map of the stack flow rate Qs and the air flow meter flow rate Qi in step S2 of Fig. 4. The flow rate map will also be described in detail later.

[0052] 4, the control device 90 determines a target value Qst of the stack flow rate Qs. The control device 90 determines a target current that the fuel cell stack 30 should output in response to the power required by the load of the fuel cell system 1, in order to generate power in the fuel cell system 1. The control device 90 determines the target value Qst, for example, based on a predetermined stack flow rate Qs for achieving the target current.

[0053] In step S4 of FIG. 4, the control device 90 refers to the exhaust pipe pressure loss map and the intake pipe pressure loss map shown in FIG. 5 based on the target value Qst of the stack flow rate Qs and the flow rate map, and determines the exhaust pipe pressure loss Do and the intake pipe pressure loss Di at the target value Qst.

[0054] More specifically, the control device 90 refers to a flow rate map based on the target value Qst of the stack flow rate Qs and determines the air flow meter flow rate Qi at the target value Qst. Furthermore, the control device 90 refers to an exhaust pipe pressure loss map and an intake pipe pressure loss map based on the air flow meter flow rate Qi at the target value Qst and determines the exhaust pipe pressure loss Do and the intake pipe pressure loss Di at the target value Qst.

[0055] In step S5 of FIG. 4, the control device 90 acquires the atmospheric pressure Pa from the atmospheric pressure sensor 50.

[0056] In step S6 of Fig. 4, the control device 90 determines the pressure ratio R of the air compressor 60. The control device 90 determines the inlet pressure Pci based on the difference between the atmospheric pressure Pa and the intake pipe pressure loss Di at the target value Qst of the stack flow rate Qs. The control device 90 determines the outlet pressure Pco based on the sum of the atmospheric pressure Pa and the exhaust pipe pressure loss Do at the target value Qst of the stack flow rate Qs. That is, the pressure ratio R is calculated using equation (2). R=Pco / Pci=(Pa+Do) / (Pa-Di) …(2)

[0057] In step S7 of Fig. 4, the control device 90 determines the rotation speed n of the air compressor 60. More specifically, the control device 90 determines the rotation speed n by referencing the information on the characteristics of the air compressor 60 shown in Fig. 2 based on the air flow meter flow rate Qi at the target value Qst and the pressure ratio R. That is, the control device 90 determines the rotation speed n for achieving the target value Qst based on the characteristics of the air compressor 60 and the pressure ratio R. Note that the information on the characteristics of the air compressor 60 is determined in advance, for example, when the fuel cell system 1 is manufactured, and is stored in the control device 90.

[0058] 4, the control device 90 performs power generation. That is, the control device 90 controls the air compressor 60 at the rotation speed n determined to achieve the target value Qst. As a result, cathode gas that satisfies the target value Qst is supplied to the fuel cell stack 30. Furthermore, anode gas that achieves the target current is supplied to the fuel cell stack 30, allowing the fuel cell stack 30 to generate power.

[0059] That is, the control device 90 refers to an exhaust pipe pressure loss map and an intake pipe pressure loss map based on the target value Qst of the stack flow rate Qs for achieving the target current in power generation by the fuel cell system 1, and determines the exhaust pipe pressure loss Do at the target value Qst and the intake pipe pressure loss Di at the target value Qst. A method for creating maps including the pressure loss map in step S2 of Fig. 4 will be described below.

[0060] A-3. How to create a pressure loss map: Fig. 6 is a flowchart showing a method for creating the map. In step S21 of Fig. 6, the control device 90 fully closes the first valve 110 and the second valve 120. Furthermore, the control device 90 fully opens the third valve 130. In other words, the control device 90 does not allow the cathode gas discharged from the air compressor 60 to flow through the fuel cell stack 30. The control device 90 allows the cathode gas discharged from the air compressor 60 to flow through the bypass pipe 140 and the bearing exhaust pipe 66 to the system exhaust section 20.

[0061] With this configuration, when determining the intake pipe pressure loss map and the exhaust pipe pressure loss map, the cathode gas does not flow through the fuel cell stack 30. In other words, the fuel cell system 1 of this embodiment can more accurately determine the pressure losses in the intake pipe Li and the exhaust pipe Lo by excluding the pressure loss caused by the fuel cell stack 30.

[0062] In steps S22 to S25 of Fig. 6, the control device 90 determines the pressure loss corresponding to the air flow meter flow rate Qi by changing the rotation speed n of the air compressor 60. For example, the control device 90 sets the rotation speed n of the air compressor 60 based on a plurality of predetermined, mutually different air flow meter flow rates Qi. For example, the control device 90 increases the rotation speed n of the air compressor 60 from the minimum rotation speed to the maximum rotation speed, and proceeds to step S26 for each unit flow rate. The process for each step will be described below.

[0063] 6, the control device 90 sets the rotation speed n of the air compressor 60. For example, when executing step S22 for the first time, the control device 90 sets the rotation speed n to the minimum rotation speed of the air compressor 60. In step S22 from the second time onwards, the control device 90 sets the rotation speed n of the air compressor 60 to a rotation speed greater than the previous rotation speed.

[0064] 6, the control device 90 operates the air compressor 60 at the set rotation speed, thereby drawing the cathode gas into the fuel cell system 1.

[0065] In step S24 of FIG. 6, the control device 90 obtains the air flow meter flow rate Qi from the air flow meter 70.

[0066] In step S25 of Fig. 6, the control device 90 determines whether the air flow meter flow rate Qi has already been acquired. If the acquired air flow meter flow rate Qi is an acquired value, the control device 90 returns the process to step S22. As a result, the control device 90 changes the rotation speed n so as to obtain a different air flow meter flow rate Qi. If the acquired air flow meter flow rate Qi is a value that has not already been acquired, the control device 90 proceeds to step S26.

[0067] The process of step S26 in FIG. 6 is the same as the process of step S5 in FIG.

[0068] In the process of step S27 in FIG. 6, the control device 90 acquires the outlet pressure Pco from the pressure sensor 80.

[0069] 6, the control device 90 determines the exhaust pipe pressure loss Do corresponding to the air flow meter flow rate Qi based on the difference between the atmospheric pressure Pa and the outlet pressure Pco. That is, the exhaust pipe pressure loss Do is calculated using equation (3). Do = Pa - Pco …(3)

[0070] In step S29 of Fig. 6, the control device 90 determines the inlet pressure Pci based on the outlet pressure Pco and the rotation speed n of the air compressor 60. More specifically, the control device 90 determines the pressure ratio R corresponding to the air flow meter flow rate Qi and the rotation speed n based on information representing the characteristics of the air compressor 60 in Fig. 3. The control device 90 determines the calculated value of the inlet pressure Pci using equation (1) based on the determined pressure ratio R and outlet pressure Pco.

[0071] 6, the control device 90 determines the intake pipe pressure loss Di corresponding to the air flow meter flow rate Qi based on the difference between the calculated value of the inlet pressure Pci and the atmospheric pressure Pa. That is, the intake pipe pressure loss Di is calculated from equation (4) based on equation (2). Di = Pa - Pci = Pa - (Pa + Do) / R … (4)

[0072] 6, the control device 90 determines the bearing cooling flow rate Qb from equation (5). As described above, the pressure loss in the bearing intake pipe 65 is defined as Dtbi, the pressure loss in the bearing exhaust pipe 66 as Dtbo, the pressure loss in the bearing portion of the motor 63 as Dtb, and the pressure loss in the exhaust pipe Lo as Do. The total pressure loss in the fuel cell system 1 between the system intake section 10, stack intake section 40, system exhaust section 20, and cathode flow path 31 is defined as Dtf. Qb=((Dtbi+Dtbo+Dtb+Do) / (Dtf+Do))×Qi …(5)

[0073] The bearing intake pipe pressure loss Dtbi, the bearing exhaust pipe pressure loss Dtbo, the bearing pressure loss Dtb, and the system pressure loss Dtf are determined in advance when the fuel cell system 1 is manufactured, for example, and are stored in the control device 90.

[0074] 6, the control device 90 determines the stack flow rate Qs. Because the sum of the bearing cooling flow rate Qb and the stack flow rate Qs is the air flow meter flow rate Qi, the control device 90 determines the stack flow rate Qs using equation (6). Qs = Qi - Qb …(6)

[0075] In step S33 of FIG. 6, the control device 90 determines whether or not there is an unset rotation speed n of the air compressor 60. If there is an unset rotation speed, the control device 90 returns the process to step S22. If there is no unset rotation speed, the control device 90 ends the process. For example, the control device 90 repeats the process while gradually increasing the rotation speed n of the air compressor 60 from the minimum rotation speed to the maximum rotation speed. If the rotation speed n reaches the maximum rotation speed, the control device 90 ends the process.

[0076] As described above, the control device 90 creates various maps by determining the exhaust pipe pressure loss Do, the intake pipe pressure loss Di, and the stack flow rate Qs according to the air flow meter flow rate Qi.

[0077] That is, the control device 90 creates a pressure loss map while changing the air flow meter flow rate Qi with the first valve 110 and the second valve 120 closed and the third valve 130 open. Specifically, the control device 90 creates an exhaust pipe pressure loss map corresponding to the air flow meter flow rate Qi based on the difference between the atmospheric pressure Pa and the outlet pressure Pco. The control device 90 creates an intake pipe pressure loss map corresponding to the air flow meter flow rate Qi based on the difference between the calculated value of the inlet pressure Pci and the atmospheric pressure Pa.

[0078] Furthermore, the control device 90 creates a flow rate map while changing the air flow meter flow rate Qi. Specifically, the control device 90 creates a flow rate map of the stack flow rate Qs according to the air flow meter flow rate Qi based on the intake manifold pressure loss Di, the exhaust manifold pressure loss Do, the bearing exhaust manifold pressure loss Dtbo, the bearing intake manifold pressure loss Dtbi, and the system pressure loss Dtf.

[0079] As described above, the fuel cell system 1 of this embodiment controls the flow rate of the cathode gas depending on the product in which the fuel cell system 1 is installed. The fuel cell system 1 of this embodiment is installed in various products such as passenger cars, trucks, ships, and stationary power generation facilities. The pressure loss in the intake pipe Li and the exhaust pipe Lo varies depending on the product in which the fuel cell system 1 is installed. By adopting this configuration, the fuel cell system 1 of this embodiment determines an intake pipe pressure loss map and an exhaust pipe pressure loss map before generating power. This allows the fuel cell system 1 of this embodiment to control the rotation speed n of the air compressor 60 taking into account the pressure loss in the intake pipe Li and the exhaust pipe Lo during power generation. Therefore, the fuel cell system 1 of this embodiment can more accurately control the flow rate of the cathode gas supplied to the fuel cell stack 30 than a configuration that uses a fixed pressure loss regardless of the specifications of the intake pipe Li and the exhaust pipe Lo.

[0080] Furthermore, the fuel cell system 1 of this embodiment creates a pressure loss map with the first valve 110 and the second valve 120 closed and the third valve 130 open. By adopting this configuration, as described above, the intake pipe pressure loss map and the exhaust pipe pressure loss map are determined, so that the cathode gas does not flow into the fuel cell stack 30 while it is flowing through the fuel cell system 1. In other words, the fuel cell system 1 of this embodiment can more accurately determine the pressure loss in the intake pipe Li and the exhaust pipe Lo by excluding the pressure loss due to the fuel cell stack 30.

[0081] Furthermore, as described above, the fuel cell system 1 of this embodiment circulates cathode gas through the bearing of the air compressor 60. The bearing of the air compressor 60 becomes hot due to the rotation of the motor 63 while the air compressor 60 is operating. This causes the shaft and bearing to weld together, changing the characteristics of the air compressor 60. Therefore, even if the control device 90 performs control by referring to a predetermined intake pipe pressure loss map and exhaust pipe pressure loss map, the flow rate of the cathode gas may deviate from the ideal value. The fuel cell system 1 of this embodiment cools the bearing of the air compressor 60 by flowing cathode gas through it. Therefore, the fuel cell system 1 of the present disclosure can control the flow rate of the cathode gas circulating in the fuel cell stack 30 more accurately than a configuration in which the bearing is not cooled.

[0082] The cathode gas flowing through the bearing is a portion of the cathode gas discharged by the air compressor 60. Therefore, the stack flow rate Qs is smaller than the air flow meter flow rate Qi. In other words, because the stack flow rate Qs is not considered to be the air flow meter flow rate Qi, the accurate exhaust pipe pressure loss Do and intake pipe pressure loss Di cannot be determined based solely on the target value Qst of the stack flow rate Qs to be supplied to the fuel cell stack 30. Furthermore, the flow rate of the cathode gas flowing through the bearing varies depending on the exhaust pipe pressure loss Do and the intake pipe pressure loss Di. For example, depending on the magnitude of the exhaust pipe pressure loss Do, the pressure in the system exhaust section 20 increases, making it difficult for the cathode gas to flow into the bearing. In other words, the intake pipe Li and exhaust pipe Lo affect the temperature of the bearing. Therefore, prior to power generation, the fuel cell system 1 of this embodiment creates a flow rate map that indicates the air flow meter flow rate Qi corresponding to the stack flow rate Qs based on the pressure losses in the intake pipe Li, exhaust pipe Lo, etc. As a result, in power generation, the fuel cell system 1 of the present disclosure can accurately control the flow rate of the cathode gas flowing through the fuel cell stack 30 based on the target value Qst of the stack flow rate Qs and the flow rate map, taking into account the flow rate of the cathode gas flowing through the bearing.

[0083] B. Other Embodiments: (1) In the above embodiment, the fuel cell system 1 determines the intake pipe pressure loss map and the intake pipe pressure loss map while the first valve 110 and the second valve 120 are closed and the third valve 130 is open. However, the fuel cell system 1 may determine the intake pipe pressure loss map and the intake pipe pressure loss map while the first valve 110 and the second valve 120 are open and the third valve 130 is closed. Alternatively, the fuel cell system 1 may not include the first valve 110 to the third valve 130 and the bypass pipe 140. In other words, the fuel cell system 1 may create a pressure loss map while the cathode gas is circulating through the cathode flow path 31. By adopting such a configuration, the fuel cell system 1 can more easily control the first valve 110 to the third valve 130 than by controlling the first valve 110 to the third valve 130.

[0084] (2) In the above embodiment, the air compressor 60 is provided with a bearing intake pipe 65 and a bearing exhaust pipe 66. However, the air compressor 60 does not have to be provided with the bearing intake pipe 65 and the bearing exhaust pipe 66. In this embodiment, the fuel cell system 1 can supply all of the cathode gas discharged by the air compressor 60 to the fuel cell stack 30. In other words, the air flow meter flow rate Qi is regarded as the stack flow rate Qs.

[0085] Therefore, the control device 90 may refer to an exhaust pipe pressure loss map and an intake pipe pressure loss map based only on the target value Qst of the stack flow rate Qs, and determine the exhaust pipe pressure loss Do and the intake pipe pressure loss Di at the target value Qst. In the first embodiment, the control device 90 determines the exhaust pipe pressure loss Do and the intake pipe pressure loss Di at the target value Qst of the stack flow rate Qs based on the target value Qst and the flow rate map. However, in this embodiment, the flow rate map is not used, and therefore there is no need to create a flow rate map. Therefore, the fuel cell system 1 can easily configure the air compressor 60. Furthermore, the fuel cell system 1 can be easily controlled.

[0086] (3) In the above embodiment, the air compressor 60 is a two-stage boost type turbo compressor. However, the air compressor 60 may be a one-stage boost type turbo compressor.

[0087] (4) In the above embodiment, the components of the fuel cell system 1 other than the atmospheric pressure sensor 50, the air flow meter 70, the air cleaner 100, and the first temperature sensor 160 are configured as one module M1 regardless of the positions of the intake pipe Li and the exhaust pipe Lo. However, the fuel cell system 1 does not have to be configured as one module M1, or one module M1 may be configured by a combination of components different from those in the above embodiment.

[0088] (5) In the above embodiment, the atmospheric pressure Pa is a pressure value acquired by the atmospheric pressure sensor 50. However, the atmospheric pressure Pa may be a predetermined value. For example, the atmospheric pressure Pa may be a standard atmospheric pressure.

[0089] (6) In the above embodiment, the air flow meter 70 is provided in the second intake pipe Li2, but it may be provided in the first intake pipe Li1.

[0090] (7) In the above embodiment, the control device 90 controls the stack flow rate Qs using the air compressor 60. However, the control device 90 may also control the stack flow rate Qs using the third valve 130. For example, the control device 90 may determine the stack flow rate Qs using equation (7) based on a predetermined relationship between the degree of opening and closing of the third valve 130 and the flow rate of the cathode gas flowing through the third valve 130. The flow rate of the cathode gas flowing through the third valve 130 is defined as the bypass flow rate Qd. Qs = Qi - Qb - Qd … (7)

[0091] (8) In steps S22 to S25 of Fig. 6 in the above embodiment, the control device 90 increases the rotation speed n of the air compressor 60 from the minimum rotation speed to the maximum rotation speed, and proceeds to step S26 for each unit flow rate. However, other methods may be used to set the rotation speed n. For example, the control device 90 may set the rotation speed n within a predetermined range of rotation speeds, regardless of the minimum or maximum rotation speed of the air compressor 60.

[0092] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit of the present disclosure. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above problems or achieve some or all of the above effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0093] 1... fuel cell system, 10... system intake section, 20... system exhaust section, 21... first system exhaust section, 22... second system exhaust section, 30... fuel cell stack, 31... cathode flow path, 40... stack intake section, 41... first stack intake section, 42... second stack intake section, 43... third stack intake section, 50... atmospheric pressure sensor, 60... air compressor, 61... first compressor, 62... second compressor, 63... motor, 63s... rotating shaft, 64... relay piping, 65... bearing intake pipe, 66... ​​bearing exhaust pipe, 70... air flow meter, 80... pressure sensor, 90... control device, 91... CPU, 92... ROM, 93... RAM, 100... air cleaner, 110... first valve, 120... second valve, 130...Third valve, 140...Bypass pipe, 150...Intercooler, 160...First temperature sensor, 170...Second temperature sensor, 180...Third temperature sensor, Di...Intake manifold pressure loss, Do...Exhaust manifold pressure loss, Dtb...Bearing pressure loss, Dtbi...Bearing intake manifold pressure loss, Dtbo...Bearing exhaust manifold pressure loss, Dtf...System pressure loss, Li...Intake manifold, Li1...First intake manifold, Li2...Second intake manifold, Lie...Inlet section, Lo...Exhaust manifold, Loe...Outlet section, M1...Module, Pa...Atmospheric pressure, Pci...Inlet pressure, Pco...Outlet pressure, Qb...Bearing cooling flow rate, Qd...Bypass flow rate, Qi...Air flow meter flow rate, Qs...Stack flow rate, Qst...Target value, R...Pressure ratio, n...Rotation speed

Claims

1. 1. A fuel cell system, comprising: a system intake section through which a cathode gas supplied to the fuel cell system flows and to which an intake pipe having an intake pipe pressure loss is connected; a system exhaust section through which a cathode gas discharged from the fuel cell system flows and to which an exhaust pipe having an exhaust pipe pressure loss is connected; a fuel cell stack that generates electricity using a cathode gas supplied via the system intake section and discharges the cathode gas used for power generation via the system exhaust section; an atmospheric pressure sensor for acquiring atmospheric pressure; an air compressor that compresses the cathode gas flowing through the system intake and discharges the cathode gas to the fuel cell stack; an air flow meter for acquiring an air flow rate, which is a flow rate of the cathode gas sucked into the air compressor; a pressure sensor for acquiring an outlet pressure, which is the pressure on the outlet side of the air compressor; a control device for controlling the fuel cell system, The control device Prior to power generation in the fuel cell system, the air compressor is operated at a plurality of different air flow meter flow rates while the intake pipe and the exhaust pipe are connected to the fuel cell system; creating an exhaust pipe pressure loss map according to the air flow meter flow rate based on a difference between the atmospheric pressure and the outlet pressure, which is the pressure of the cathode gas at the outlet of the exhaust pipe; creating an intake pipe pressure loss map corresponding to the air flow meter flow rate based on the difference between a calculated value of an inlet pressure, which is the pressure on the inlet side of the air compressor determined based on the outlet pressure and the rotation speed of the air compressor, and the atmospheric pressure, which is the pressure of the cathode gas at the inlet of the intake pipe; In the power generation of the fuel cell system, determining an exhaust pipe pressure loss at the target value and an intake pipe pressure loss at the target value by referring to the exhaust pipe pressure loss map and the intake pipe pressure loss map based on a target value of a stack flow rate supplied to the fuel cell stack to achieve a target current; a rotation speed for realizing the target value at a pressure ratio between the inlet pressure, which is determined based on a difference between the atmospheric pressure and an intake pipe pressure loss at the target value, and the outlet pressure, which is determined based on a sum of the atmospheric pressure and an exhaust pipe pressure loss at the target value, and the air compressor is controlled based on the determined rotation speed.

2. 10. The fuel cell system of claim 1, further comprising: a first valve provided on the inlet side of the fuel cell stack for changing the flow rate of the cathode gas supplied to the fuel cell stack; a second valve provided on the outlet side of the fuel cell stack to change the flow rate of the cathode gas discharged from the fuel cell stack; a bypass pipe connecting the inlet side of the first valve and the outlet side of the second valve; a third valve that changes the flow rate of the cathode gas flowing through the bypass pipe, The control device The fuel cell system creates the intake pipe pressure loss map and the intake pipe pressure loss map while the first valve and the second valve are closed and the third valve is open.

3. 3. The fuel cell system according to claim 2, The air compressor further comprises: a bearing intake pipe that circulates a portion of the cathode gas discharged by the air compressor through a bearing of the air compressor and has a bearing intake pipe pressure loss as a pressure loss; a bearing exhaust pipe that causes the cathode gas that has flowed through the bearing to flow through the system exhaust section and has a bearing exhaust pipe pressure loss as a pressure loss. The control device and creating a flow rate map of a stack flow rate corresponding to the air flow meter flow rate based on the intake pipe pressure loss, the exhaust pipe pressure loss, the bearing exhaust pipe pressure loss, the bearing intake pipe pressure loss, and a pressure loss of the fuel cell system while the air compressor is operating prior to power generation in the fuel cell system; In power generation in the fuel cell system, the exhaust pipe pressure loss and the intake pipe pressure loss are determined based on the target value and the flow rate map.

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