Fuel cell system

Abstract

To provide a fuel cell system capable of supplying a necessary amount of reaction gas to a fuel cell in a high output area of the fuel cell without enlarging a physical constitution of an injecting device.SOLUTION: A fuel cell system 1 includes a control unit 14 for controlling an injector 51 and a linear solenoid valve 52. In the case of stipulating areas of output of an FC stack 11 as a low output area AR1, a middle output area AR2, and a high output area AR3 in order from a lower area toward a higher area, the control unit 14 makes the injector 51 perform injection in the low output area AR1, makes at least one of the injector 51 and the linear solenoid valve 52 perform injection in the middle output area AR2, and makes the injector 51 and the linear solenoid valve 52 perform injection at the same time in the high output area AR3.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a fuel cell system having a fuel cell that generates electricity by receiving supplies of a fuel gas and an oxidant gas.

Background Art

[0002] Patent Document 1 discloses a fuel cell system having an injector and a linear solenoid valve as an injection device for injecting a reaction gas (gaseous fuel) supplied to a fuel cell.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the fuel cell system disclosed in Patent Document 1, in the high output region of the fuel cell, the injector is stopped and only the linear solenoid valve is used for injection. However, in the high output region of the fuel cell, the supply flow rate of the reaction gas to the fuel cell increases, so there is a risk that the size of the linear solenoid valve has to be increased in order to increase the injection flow rate of the linear solenoid valve.

[0005] Therefore, the present disclosure has been made to solve the above-described problems, and an object thereof is to provide a fuel cell system that can supply a required amount of reaction gas to a fuel cell without increasing the size of an injection device in a high output region of the fuel cell.

Means for Solving the Problems

[0006] One aspect of the present disclosure made to solve the above problems is a fuel cell system having a fuel cell, a first injection device that intermittently injects a reaction gas supplied to the fuel cell, and a second injection device that continuously injects the reaction gas, the fuel cell system having a control unit that controls the first injection device and the second injection device, and when defining the output region of the fuel cell as a low output region, a medium output region, and a high output region in order from the lower to the higher, the control unit causes the first injection device to inject in the low output region, causes at least one of the first injection device and the second injection device to inject in the medium output region, and causes the first injection device and the second injection device to inject simultaneously in the high output region.

[0007] According to this aspect, in the high output region where the power generation amount of the fuel cell increases and thus the supply flow rate of the reaction gas to the fuel cell increases, the reaction gas is injected not only from the second injection device but also from the first injection device. Therefore, in the high output region, it is not necessary to expand the size of the second injection device to increase the injection flow rate from the second injection device. Thus, in the high output region, the amount of reaction gas necessary for power generation of the fuel cell can be supplied to the fuel cell without expanding the size of the second injection device.

[0008] In the above aspect, when defining the medium output region as a first medium output region and a second medium output region in order from the lower to the higher of the output of the fuel cell, it is preferable that the control unit causes the first injection device and the second injection device to inject simultaneously in the first medium output region, and causes the second injection device to inject in the second medium output region.

[0009] According to this aspect, in the first medium output region, since the first injection device and the second injection device are caused to inject simultaneously, the necessary flow rate can be ensured more accurately by adjusting the injection flow rate of the first injection device and the injection flow rate of the second injection device. In particular, in the second medium output region, by causing only the second injection device to inject, the injection of the first injection device can be stopped and the number of operating times of the first injection device can be suppressed, so that the durability of the first injection device can be improved.

[0010] In the above aspect, in the high output region, it is preferable that the control unit adjusts the flow rate of the reaction gas supplied to the fuel cell by keeping the injection flow rate of the second injection device constant while changing the injection flow rate of the first injection device.

[0011] According to this aspect, in the high output region, the injection flow rate of the first injection device can be finely adjusted, so that the flow rate of the reaction gas supplied to the fuel cell can be accurately adjusted. In addition, since the number of operations of the second injection device can be suppressed, the durability of the second injection device can be improved.

[0012] In the above aspect, in the high output region, it is preferable that the control unit adjusts the flow rate of the reaction gas supplied to the fuel cell by keeping the injection flow rate of the first injection device constant while changing the injection flow rate of the second injection device.

[0013] According to this aspect, since the injection flow rate of the first injection device is kept constant, the pulsation of the pressure of the reaction gas generated during the injection of the first injection device can be suppressed. In addition, since the number of operations of the first injection device can be suppressed, the durability of the first injection device can be improved.

[0014] In the above aspect, in the medium output region, it is preferable that the control unit simultaneously injects the first injection device and the second injection device, and in the medium output region and the high output region, the control unit adjusts the flow rate of the reaction gas supplied to the fuel cell by keeping the injection flow rate of the first injection device constant while changing the injection flow rate of the second injection device.

[0015] According to this aspect, since the injection flow rate of the first injection device is made constant, it is possible to suppress the pulsation of the pressure of the reaction gas generated during the injection of the first injection device. In addition, since the number of operating times of the first injection device can be suppressed, the durability of the first injection device can be improved. And not only in the high output region, but also in a wide region including the medium output region, it is possible to suppress the pulsation of the pressure of the reaction gas generated during the injection of the first injection device, and also to suppress the number of operating times of the first injection device to improve the durability of the first injection device.

[0016] In the above aspect, it has an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, and the control unit preferably injects the first injection device in synchronization with the timing of opening the exhaust and drainage valve in the high output region.

[0017] According to this aspect, in the high output region, without increasing the size of the second injection device, the shortage of the supply flow rate of the reaction gas to the fuel cell due to opening the exhaust and drainage valve can be compensated by the first injection device.

[0018] In the above aspect, it has an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, and the control unit preferably injects the second injection device in synchronization with the timing of opening the exhaust and drainage valve in the high output region.

[0019] According to this aspect, in the high output region, without increasing the size of the first injection device, the shortage of the supply flow rate of the reaction gas to the fuel cell due to opening the exhaust and drainage valve can be compensated by the second injection device.

[0020] In the above aspect, it has an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, and the control unit preferably injects the second injection device in synchronization with the timing of opening the exhaust and drainage valve in the low output region.

[0021] According to this aspect, in the low-output region, without expanding the size of the first injector, the shortage of the supply flow rate of the reaction gas to the fuel cell due to opening the exhaust and drain valve can be compensated by the second injector.

Advantages of the Invention

[0022] According to the fuel cell system of the present disclosure, in the high-output region of the fuel cell, the required amount of reaction gas can be supplied to the fuel cell without expanding the size of the injector.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0024] Embodiments of the fuel cell system of the present disclosure will be described.

[0025] <Regarding the Outline of the Fuel Cell System> First, the outline of the fuel cell system 1 of the present embodiment will be described. The fuel cell system 1 is a system that is mounted on a fuel cell vehicle and supplies electric power to its drive motor (not shown).

[0026] (Regarding the schematic configuration of the fuel cell system) As shown in FIG. 1, the fuel cell system 1 includes an FC stack 11, a hydrogen system 12, an air system 13, and a control unit 14. Note that the FC stack 11 is an example of the "fuel cell" of the present disclosure.

[0027] The FC stack 11 generates electricity by receiving the supply of fuel gas and oxidant gas. In the present embodiment, the fuel gas is hydrogen gas and the oxidant gas is air. That is, the FC stack 11 generates electricity by receiving the supply of hydrogen gas from the hydrogen system 12 and the supply of air from the air system 13. Then, the electric power generated by the FC stack 11 is supplied to the drive motor (not shown) via an inverter (not shown). Note that the fuel gas and hydrogen gas are examples of the "reaction gas" of the present disclosure.

[0028] The hydrogen system 12 is provided on the anode side of the FC stack 11. This hydrogen system 12 includes a hydrogen supply passage 21, a hydrogen discharge passage 22, and a hydrogen circulation passage 23. The hydrogen supply passage 21 is a passage for supplying hydrogen gas from the hydrogen tank 31 to the FC stack 11. The hydrogen discharge passage 22 is a passage for discharging the hydrogen gas discharged from the FC stack 11 (hereinafter referred to as "hydrogen off-gas") to the outside of the fuel cell system 1. The hydrogen circulation passage 23 is a passage for circulating at least a part of the hydrogen off-gas from the hydrogen discharge passage 22 to the hydrogen supply passage 21. Note that the hydrogen off-gas is an example of the "reaction off-gas" of the present disclosure.

[0029] The hydrogen-based system 12 includes, in the hydrogen supply passage 21, a main stop valve 32, a pressure reducing valve 33, and a fuel supply device 34 in order from the hydrogen tank 31 side. The main stop valve 32 is a valve that switches between supplying and shutting off the supply of hydrogen gas from the hydrogen tank 31 to the hydrogen supply passage 21. The pressure reducing valve 33 is a pressure regulating valve for reducing the pressure of the hydrogen gas.

[0030] The fuel supply device 34 is a device that supplies hydrogen gas to the FC stack 11, and includes a fuel injection unit 41 and an ejector 42.

[0031] The fuel injection unit 41 is a mechanism for injecting hydrogen gas. In the present embodiment, as an injection device for injecting hydrogen gas, it includes an injector 51 and a linear solenoid valve 52. Note that the injector 51 is an example of the "first injection device" of the present disclosure, and the linear solenoid valve 52 is an example of the "second injection device" of the present disclosure.

[0032] The injector 51 is an on-off valve (ON / OFF valve) that can control the opening degree of its injection port 51a only between the fully closed opening degree and the fully open opening degree, and intermittently injects hydrogen gas.

[0033] The linear solenoid valve 52 is a valve that opens and closes the injection port 52a of hydrogen gas by driving a linear solenoid (not shown), and is a valve that continuously injects hydrogen gas. Further, this linear solenoid valve 52 is a valve that can control the opening degree of its injection port 52a to be maintained at a predetermined opening degree between the fully closed opening degree (opening degree is 100%) and the fully open opening degree (opening degree is 0%) so as to adjust the injection flow rate of hydrogen gas to a predetermined amount. Note that the "predetermined opening degree" is a value that changes depending on the operating conditions, and the "predetermined amount" is an amount corresponding to the required power generation amount in the FC stack 11.

[0034] The ejector 42 is provided at a position downstream of the fuel injection unit 41 (downstream in the flow direction of the hydrogen gas flowing through the hydrogen supply passage 21) and upstream of the FC stack 11 (upstream in the flow direction of the hydrogen gas flowing through the hydrogen supply passage 21). The ejector 42 includes an inlet 42a, an outlet 42b, and a suction port 42c.

[0035] The inlet 42a is an inlet for hydrogen gas injected from the fuel injection unit 41. In the example shown in FIG. 1, it is connected to the injection port 51a of the injector 51 and the injection port 52a of the linear solenoid valve 52. The outlet 42b is a part for discharging hydrogen gas and is connected to the FC stack 11. Further, the suction port 42c is a part for sucking hydrogen off-gas and is connected to the hydrogen circulation passage 23.

[0036] This ejector 42 sucks the hydrogen off-gas discharged from the FC stack 11 to the hydrogen discharge passage 22 through the hydrogen circulation passage 23 at the suction port 42c by the negative pressure generated by introducing the hydrogen gas injected from the fuel injection unit 41 through the inlet 42a. Then, the ejector 42 merges the hydrogen off-gas sucked from the suction port 42c with the hydrogen gas introduced from the inlet 42a and circulates it to the FC stack 11 from the outlet 42b. In this way, the hydrogen off-gas discharged from the FC stack 11 to the hydrogen discharge passage 22 is circulated to the FC stack 11 through the ejector 42.

[0037] Also, in the hydrogen discharge passage 22 of the hydrogen system 12, a gas-liquid separator 61 and an exhaust drain valve 62 are arranged. The gas-liquid separator 61 is a device for separating moisture in the hydrogen off-gas. The gas-liquid separator 61 is connected to the suction port 42c of the ejector 42 through the hydrogen circulation passage 23. The exhaust drain valve 62 controls the discharge of the hydrogen off-gas discharged from the FC stack 11 to the outside, and is a valve that switches between discharging and blocking the hydrogen off-gas and moisture from the gas-liquid separator 61 to the air discharge passage 72 (described later) of the air system 13.

[0038] The air system 13 is provided on the cathode side of the FC stack 11. This air system 13 includes an air supply passage 71, an air discharge passage 72, and an air bypass passage 73. The air supply passage 71 is a passage for supplying air from outside the fuel cell system 1 to the FC stack 11. The air discharge passage 72 is a passage for discharging the air (hereinafter referred to as "air off-gas") discharged from the FC stack 11 to the outside of the fuel cell system 1. The air bypass passage 73 is a passage that bypasses (detours around) the FC stack 11 and connects the air supply passage 71 and the air discharge passage 72.

[0039] In the air supply passage 71, the air system 13 includes, in order from the upstream side, an air cleaner 81, a blower 82, an intercooler 83, and a supply air valve 84. The air cleaner 81 is a device that purifies the air taken in from outside the fuel cell system 1. The blower 82 is a device that supplies air to the FC stack 11. The intercooler 83 is a device that cools the air. The supply air valve 84 is a valve that controls the flow rate of the air supplied from the air supply passage 71 to the FC stack 11.

[0040] Also, in the air discharge passage 72 of the air system 13, an exhaust air valve 91 is arranged. The exhaust air valve 91 is a valve that controls the flow rate of the air off-gas discharged from the FC stack 11 to the air discharge passage 72.

[0041] Furthermore, in the air bypass passage 73 of the air system 13, a bypass air valve 101 is arranged. The bypass air valve 101 is a valve that controls the flow rate of the air in the air bypass passage 73.

[0042] The control unit 14 is a device having, for example, an arithmetic processing unit such as a CPU, a storage unit such as a ROM that stores a control program and control data processed by the CPU, and a RAM used as various work areas for control processing, and an input / output interface unit. Then, the control unit 14 performs various controls of the fuel cell system 1 according to the control program stored in the storage unit.

[0043] Specifically, the control unit 14 controls, for example, the operation of switching the opening degree of the injection port 51a of the injector 51 between the fully closed opening degree and the fully open opening degree, and controls the opening degree of the injection port 52a of the linear solenoid valve 52 to be maintained at a predetermined opening degree. In addition, the control unit 14 also controls the main stop valve 32, the pressure reducing valve 33, the exhaust and drainage valve 62, the blower 82, the supply air valve 84, the discharge air valve 91, the bypass air valve 101, and the like.

[0044] (Regarding the operation of the fuel cell system) In the fuel cell system 1 configured as described above, in the hydrogen system 12, the hydrogen gas supplied from the hydrogen supply passage 21 to the FC stack 11 is discharged to the outside via the hydrogen discharge passage 22 as hydrogen off-gas after being used for power generation in the FC stack 11, or is sucked into the ejector 42 via the hydrogen discharge passage 22 and the hydrogen circulation passage 23. In the air system 13, the air supplied from the air supply passage 71 to the FC stack 11 is discharged to the outside via the air discharge passage 72 as air off-gas after being used for power generation in the FC stack 11. Note that, depending on the situation, in the air system 13, the air supplied from the air supply passage 71 is discharged to the outside via the air bypass passage 73 and the air discharge passage 72 so as to bypass the FC stack 11.

[0045] (Regarding the control of the injector and the linear solenoid valve in each output region of the fuel cell) In such a fuel cell system 1, as shown in FIG. 2, as the output of the FC stack 11 (that is, the power generated by the FC stack 11) increases, that is, as the power generation amount of the FC stack 11 increases, the required supply flow rate of hydrogen gas to the FC stack 11 (denoted as "required flow rate" in FIG. 2) increases.

[0046] Here, the output region of the FC stack 11 is defined, in order from the lower to the higher side, as a low-output region AR1, a medium-output region AR2 (i.e., a first medium-output region AR2-1 and a second medium-output region AR2-2), and a high-output region AR3. Therefore, the content of the control of the injector 51 and the linear solenoid valve 52 performed in each output region will be described below. In FIG. 2 and FIGS. 3 to 6 described later, the injector 51 is denoted as "INJ" and the linear solenoid valve 52 is denoted as "LSV".

[0047] (First Embodiment) First, the first embodiment will be described.

[0048] In this embodiment, as shown in FIG. 2, in the low-output region AR1, the control unit 14 causes the injector 51 to inject while stopping the linear solenoid valve 52. Specifically, as the required output of the FC stack 11 increases, the control unit 14 increases the injection flow rate (of hydrogen gas) of the injector 51. Note that the low-output region AR1 is, for example, an output region having a size of less than 20% of the maximum output (100%) of the FC stack 11.

[0049] Next, in the first medium-output region AR2-1, the control unit 14 causes both the injector 51 and the linear solenoid valve 52 to inject simultaneously. At this time, the control unit 14 changes the injection flow rate of each of the injector 51 and the linear solenoid valve 52 to adjust the flow rate of hydrogen gas supplied to the FC stack 11. Specifically, as the required output of the FC stack 11 increases, the control unit 14 increases the injection flow rate of the linear solenoid valve 52 while decreasing the injection flow rate of the injector 51. Note that the first medium-output region AR2-1 is, for example, an output region having a size of 20% or more and less than 50% of the maximum output of the FC stack 11.

[0050] Next, in the second intermediate output region AR2-2, the control unit 14 causes the linear solenoid valve 52 to inject while stopping the injector 51. And at this time, the control unit 14 increases the injection flow rate of the linear solenoid valve 52 as the required output of the FC stack 11 increases. Note that the second intermediate output region AR2-2 is, for example, a region of an output having a magnitude of 50% or more and less than 80% of the maximum output of the FC stack 11.

[0051] Next, in the high output region AR3, the control unit 14 causes both the injector 51 and the linear solenoid valve 52 to inject simultaneously. Note that the high output region AR3 is, for example, a region of an output having a magnitude of 80% or more of the maximum output of the FC stack 11.

[0052] In this way, in the present embodiment, in the high output region AR3 where the power generation amount of the FC stack 11 increases and thus the supply flow rate of hydrogen gas to the FC stack 11 increases, hydrogen gas is injected not only from the linear solenoid valve 52 but also from the injector 51. Therefore, in the high output region AR3, it is not necessary to increase the size of the linear solenoid valve 52 to increase the injection flow rate from the linear solenoid valve 52. Thus, in the high output region AR3, the amount of hydrogen gas required for power generation of the FC stack 11 can be supplied to the FC stack 11 without increasing the size of the linear solenoid valve 52.

[0053] And also, in this high output region AR3, the control unit 14 adjusts the flow rate of the hydrogen gas supplied to the FC stack 11 by changing (i.e., adjusting) the injection flow rate of the injector 51 while keeping the injection flow rate of the linear solenoid valve 52 constant.

[0054] Here, the injector 51 can easily finely adjust its injection flow rate. Therefore, in the high-output region AR3, since the injection flow rate of the injector 51 can be finely adjusted, the flow rate of the hydrogen gas supplied to the FC stack 11 can be accurately adjusted. Also, since the number of operations of the linear solenoid valve 52 (i.e., the number of opening and closing operations of the injection port 52a) can be suppressed, the durability of the linear solenoid valve 52 can be improved.

[0055] As a modification, in the high-output region AR3, as shown in FIG. 3, the control unit 14 may cause the injector 51 to inject in synchronization with the timing of opening the exhaust and drain valve 62. That is, in FIG. 3, the injection flow rate of the injector 51 may be set to a predetermined amount (not zero) in synchronization with the timing of setting the discharge amount of the exhaust and drain valve 62 to a predetermined amount (not zero).

[0056] In this way, in the high-output region AR3, without increasing the size of the linear solenoid valve 52, the shortage of the supply flow rate of hydrogen gas to the FC stack 11 due to opening the exhaust and drain valve 62 can be compensated for by the injector 51. That is, when the hydrogen off-gas is discharged to the outside by opening the exhaust and drain valve 62, the flow rate of the circulated hydrogen off-gas decreases, and the shortage of the flow rate of the mixed gas of hydrogen gas and hydrogen off-gas supplied to the FC stack 11 can be compensated for by injecting hydrogen gas by the injector 51.

[0057] As another modification, in the low-output region AR1, as shown in FIG. 4, the control unit 14 may cause the linear solenoid valve 52 to inject in synchronization with the timing of opening the exhaust and drain valve 62. That is, in FIG. 4, the injection flow rate of the linear solenoid valve 52 may be set to a predetermined amount (not zero) in synchronization with the timing of setting the discharge amount of the exhaust and drain valve 62 to a predetermined amount (not zero).

[0058] As a result, in the low output region AR1, without increasing the size of the injector 51, the shortage of the supply flow rate of hydrogen gas to the FC stack 11 due to opening the exhaust and drain valve 62 can be compensated for by the linear solenoid valve 52. That is, when the exhaust and drain valve 62 is opened and hydrogen off-gas is discharged to the outside, the flow rate of the circulated hydrogen off-gas decreases, and the shortage of the flow rate of the mixed gas of hydrogen gas and hydrogen off-gas supplied to the FC stack 11 can be compensated for by injecting hydrogen gas by the linear solenoid valve 52.

[0059] (Second Embodiment) Next, the second embodiment will be described. Differences from the first embodiment will be described, and descriptions of points common to the first embodiment will be omitted.

[0060] In this embodiment, as shown in FIG. 5, in the high output region AR3, the control unit 14 causes both the injector 51 and the linear solenoid valve 52 to inject simultaneously. At this time, while keeping the injection flow rate of the injector 51 constant, the injection flow rate of the linear solenoid valve 52 is changed (i.e., adjusted) to adjust the flow rate of hydrogen gas supplied to the FC stack 11.

[0061] In this way, since the injection flow rate of the injector 51 is kept constant, the pulsation of the pressure of the hydrogen gas generated during injection of the injector 51 can be suppressed. Also, since the number of operating times of the injector 51 can be suppressed, the durability of the injector 51 can be improved.

[0062] As a modification, the control unit 14 may cause the linear solenoid valve 52 to inject in synchronization with the timing of opening the exhaust and drain valve 62 in the high output region AR3 in the same manner as in FIG. 4 described above.

[0063] As a result, in the high output region AR3, without increasing the size of the injector 51, the shortage of the supply flow rate of hydrogen gas to the FC stack 11 due to opening the exhaust and drain valve 62 can be compensated for by the linear solenoid valve 52. That is, when the exhaust and drain valve 62 is opened, hydrogen off-gas is discharged to the outside, so the flow rate of the circulated hydrogen off-gas decreases, and the shortage of the flow rate of the mixed gas of hydrogen gas and hydrogen off-gas supplied to the FC stack 11 can be compensated for by injecting hydrogen gas by the linear solenoid valve 52.

[0064] Also, in this embodiment as well, as another modification, in the low output region AR1, as shown in FIG. 4, the linear solenoid valve 52 may be injected in synchronization with the timing of opening the exhaust and drain valve 62.

[0065] (Third Embodiment) Next, the third embodiment will be described. Differences from the first and second embodiments will be described, and descriptions of points common to the first and second embodiments will be omitted.

[0066] In this embodiment, as shown in FIG. 6, in the medium output region AR2 (that is, the first medium output region AR2-1 and the second medium output region AR2-2) and the high output region AR3 where the required supply flow rate is greater than the injection flow rate of the injector 51 when the opening degree of the injection port 51a is the fully open degree, both the injector 51 and the linear solenoid valve 52 are injected simultaneously.

[0067] At this time, while keeping the injection flow rate of the injector 51 constant with the opening degree of the injection port 51a being the fully open degree, the flow rate of the hydrogen gas supplied to the FC stack 11 is adjusted by changing the opening degree of the injection port 52a to change (that is, adjust) the injection flow rate of the linear solenoid valve 52.

[0068] In this way, in the medium output region AR2 and the high output region AR3, hydrogen gas is injected not only from the linear solenoid valve 52 but also from the injector 51. Therefore, in the medium output region AR2 and the high output region AR3, it is not necessary to increase the injection flow rate from the linear solenoid valve 52 by enlarging the size of the linear solenoid valve 52. Thus, in the medium output region AR2 and the high output region AR3, the amount of hydrogen gas required for the power generation of the FC stack 11 can be supplied to the FC stack 11 without enlarging the size of the linear solenoid valve 52.

[0069] Also, since the injection flow rate of the injector 51 is made constant, the pulsation of the pressure of the hydrogen gas generated during the injection of the injector 51 can be suppressed. Further, since the number of operations of the injector 51 can be suppressed, the durability of the injector 51 can be improved. And, not only in the high output region AR3 but also in a wide region including the medium output region AR2, the pulsation of the pressure of the hydrogen gas generated during the injection of the injector 51 can be suppressed, and the number of operations of the injector 51 can be suppressed to improve the durability of the injector 51.

[0070] As a modification, the control unit 14 may inject the linear solenoid valve 52 in synchronization with the timing of opening the exhaust and drainage valve 62 in at least one of the low output region AR1, the medium output region AR2, and the high output region AR3 in the same manner as in FIG. 4 above.

[0071] Note that the above-described embodiments are merely examples and do not limit the present disclosure in any way. It goes without saying that various improvements and modifications are possible without departing from the gist thereof.

Explanation of Reference Numerals

[0072] 1 Fuel cell system 11 FC stack 12 Hydrogen system 13 Air system 14 Control unit 21 Hydrogen supply passage 22 Hydrogen discharge passage 23 Hydrogen circulation path 31 Hydrogen tank 34 Fuel supply device 41 Fuel injection section 42 Ejector 42c Suction port 51 Injector (INJ) 52 Linear solenoid valve (LSV) 62 Exhaust and drain valve AR1 Low output region AR2 Medium output region AR2-1 First medium output region AR2-2 Second medium output region AR3 High output region

Claims

1. A fuel cell, a first injection device for intermittently injecting a reaction gas supplied to the fuel cell, a second injection device for continuously injecting the reaction gas, In a fuel cell system having: It has a control unit for controlling the first injection device and the second injection device, When defining the output region of the fuel cell in order from the lower to the higher as a low output region, a medium output region, and a high output region, The control unit: In the low output region, causes the first injection device to inject, In the medium output region, causes at least one of the first injection device and the second injection device to inject, In the high output region, causes the first injection device and the second injection device to inject simultaneously, A fuel cell system characterized by the above.

2. In the fuel cell system according to Claim 1, When defining the medium output region in order from the lower to the higher of the output of the fuel cell as a first medium output region and a second medium output region, The control unit: In the first medium output region, causes the first injection device and the second injection device to inject simultaneously, In the second medium output region, causes the second injection device to inject, A fuel cell system characterized by the above.

3. In the fuel cell system according to Claim 1 or 2, The control unit: In the high output region, while keeping the injection flow rate of the second injection device constant, adjusts the flow rate of the reaction gas supplied to the fuel cell by changing the injection flow rate of the first injection device, A fuel cell system characterized by the above.

4. In the fuel cell system according to Claim 1 or 2, The control unit: In the high output region, while keeping the injection flow rate of the first injection device constant, adjusts the flow rate of the reaction gas supplied to the fuel cell by changing the injection flow rate of the second injection device, A fuel cell system characterized by the above.

5. In the fuel cell system according to Claim 1, The control unit: In the medium output region, causes the first injection device and the second injection device to inject simultaneously, In the medium output region and the high output region, while keeping the injection flow rate of the first injection device constant, adjusts the flow rate of the reaction gas supplied to the fuel cell by changing the injection flow rate of the second injection device, A fuel cell system characterized by the above.

6. In the fuel cell system according to Claim 1 or 2, It has an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, The control unit: In the high output region, causing the first injector to inject in synchronization with the timing of opening the exhaust and drainage valve. A fuel cell system characterized by the above. **Claim 7** In the fuel cell system according to Claim 1 or 2, having an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, wherein the control unit in the high output region, causing the second injector to inject in synchronization with the timing of opening the exhaust and drainage valve. A fuel cell system characterized by the above. **Claim 8** In the fuel cell system according to Claim 1 or 2, having an exhaust and drainage valve for controlling the discharge of the reaction off-gas discharged from the fuel cell to the outside, wherein the control unit in the low output region, causing the second injector to inject in synchronization with the timing of opening the exhaust and drainage valve. A fuel cell system characterized by the above.

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