AIR VALVE AND FUEL CELL SYSTEM THAT USES AN AIR VALVE

Abstract

Air valve (50, 150) arranged in an air system (30) of a fuel cell stack (20) and designed to control a flow of air gas to be supplied to the fuel cell stack (20), comprising: a supply valve (60) designed to provide an air supply passage (34, 34a, 34b), through which the air gas, which is to be supplied to the fuel cell stack (20) from the outside, flows, to open and close; a switching valve (64) configured to switch between a state in which the air gas supplied from the outside flows through the air supply passage (34, 34a, 34b) and a state in which the air gas supplied from the outside flows through a bypass passage (35, 36), in which the bypass passage (35, 36) branches off from the air supply passage (34, 34a, 34b) and bypasses a component arranged downstream of the air valve (50, 150); and a connecting mechanism (70, 170) which is connected to the supply valve (60) and the changeover valve (64) and is designed to actuate the supply valve (60) and the changeover valve (64), in which the connecting mechanism (70, 170) has: an arm section (80, 82, 181) which is attached to the supply valve (60); and a cam plate (78, 178) which has a guide section (180) with which the arm section (80, 82, 181) is to be contacted, where the guide section (180) has: a first area (191), which is an area where the arm section (80, 82, 181) moves for an opening / closing movement of the supply valve (60); and a second area (192) which is independent of the first area (191) and is an area where the arm section (80, 82, 181) moves for an opening / closing movement of the changeover valve (64).

Description

Technical area

[0001] This specification relates to an air valve and a fuel cell system using an air valve. background

[0002] In a fuel cell system, an oxygen source (air gas) and a hydrogen source (hydrogen gas) are supplied to a fuel cell stack to generate electricity. Gas not used in electricity generation is discharged to the outside of the fuel cell system as air exhaust and hydrogen exhaust. JP 2018-137150 A discloses a configuration of an air system (passage for supplying air gas to a fuel cell stack) in a fuel cell system. In the fuel cell system of JP 2018-137150 A, air gas (outside air) is supplied to a fuel cell stack using a compressor. A valve (an inlet seal valve) is disposed on an air supply passage connecting the compressor to the fuel cell stack, and a flow rate of the air gas to be supplied to the fuel cell stack is thereby adjusted.Another valve (an exhaust-integrated valve) is disposed on an air discharge passage for discharging air exhaust, and a flow rate of the air exhaust is thereby adjusted. Further, the air supply passage is connected to the air discharge passage via a bypass passage, and a valve (a bypass valve) is disposed on the bypass passage. In JP 2018-137150 A, the air gas is supplied from the air supply passage to the air discharge passage through the bypass passage to adjust the pressure in the air supply passage (adjusting the difference between the pressure before the inlet sealing valve and the pressure after the inlet sealing valve). JP 2018-97951 A discloses another fuel cell system. JP 2013-44410 A discloses a valve for switching a flow path. JP 2012-122425 A discloses an exhaust gas circulation system. Summary of the invention

[0003]

[0003] As disclosed in JP 2018-137150 A, connecting the bypass passage to the air supply passage allows the air gas in the air supply passage to be supplied not only to the fuel cell stack but also to a component other than the fuel cell stack. However, supplying the air gas in the air supply passage to multiple locations (the fuel cell stack and the component other than the fuel cell stack) requires a valve to be disposed on the bypass passage and also requires an actuator (a motor, etc.) that operates the valve. This increases the number of components in the fuel cell system and also increases the size of the fuel cell system.

[0004] It is an object of the present invention to provide a valve (an air valve) that can achieve a compact fuel cell system.

[0005] A first technique for achieving the above-mentioned object disclosed in the present specification is an air valve according to claim 1.

[0006] A second technique disclosed in the present specification is the air valve according to the first technique, in which a third region may be arranged between the first region and the second region, and the third region is a region where neither the opening / closing movement of the supply valve nor the opening / closing movement of the switching valve is performed.

[0007] A third technique disclosed in the present specification is the air valve according to the first or second technique, in which the cam plate may be attached to a cam gear connected to a motor. The cam gear may be biased in a direction in which the cam gear rotates when the supply valve is opened, so that the arm portion is in contact with the first region while the supply valve is closed.

[0008] A fourth technique disclosed in the present specification is the air valve according to any one of the first to third techniques, wherein the second region may include a contact portion having an arc shape whose distance from a rotation center of the cam plate is constant. The arm portion may move in contact with the contact portion while the switching valve is actuated.

[0009] A fifth technique disclosed in the present specification is the air valve according to any one of the first to fourth techniques, wherein the cam plate may have a fitting portion configured to fit with the arm portion when the supply valve is closed. The fitting portion may be a groove recessed in a radially inward direction of the cam plate.

[0010] A sixth technique disclosed in the present specification is the air valve according to any one of the first to fifth techniques, wherein the first region may include a straight portion configured to contact the arm portion while the supply valve is closed. The straight portion may be maintained in contact with the arm portion for a predetermined period of time from the start of opening of the supply valve.

[0011] A seventh technique disclosed in the present specification is the air valve according to any one of the first to fifth techniques, in which a length of the second portion may be longer than a length of the first portion.

[0012] An eighth technique disclosed in the present specification is a fuel cell system including the air valve according to any one of the first to seventh techniques. In the fuel cell system, a humidifier may be disposed between the air valve and the fuel cell stack, and the bypass passage may be connected to the air supply passage and bypass the humidifier. Further, the switching valve may contact an inner wall of the air supply passage to block the air supply passage between the supply valve and the humidifier when the supply valve is closed.

[0013] A ninth technique disclosed in the present specification is the fuel cell system according to the eighth technique, wherein the air valve may include a tubular first flow portion connected to the air supply passage at a position upstream of the supply valve; and an air flow portion having one end connected to the air supply passage at a position downstream of the supply valve, another end connected to the bypass passage, and an intermediate portion connected to the first flow portion. Further, a downstream end of the supply valve may be closer to one end of the air flow portion than an upstream end of the supply valve when the supply valve is fully open. Advantageous effects of the invention

[0014] According to the first technique, it is possible to control both the flow rate of fluid flowing in the air supply passage and the flow rate of fluid flowing in the bypass passage with the single air valve. That is, the number of actuators can be reduced compared to a configuration in which valves (valve bodies and actuators that operate the valves) are separately arranged on the air supply passage and the bypass passage. Thus, the number of components in the fuel cell system can be reduced, and downsizing of the fuel cell system can be achieved. As long as one end of the bypass passage is connected to the air supply passage (the bypass passage branches off from the air supply passage), another end thereof can be connected to any suitable position. For example, in a case where a device, etc.connected to the air supply passage between the air valve and the fuel cell stack, the other end of the bypass passage may be connected to a position downstream of the device, etc. (connected to the air supply passage between the device, etc., and the fuel cell stack). That is, the bypass passage may bypass the device, etc. arranged on the air supply passage between the air valve and the fuel cell stack. Alternatively, the other end of the bypass passage may be connected to a position downstream of the fuel cell stack (air discharge passage). That is, the bypass passage may bypass the fuel cell stack.

[0015] According to the second technique, it is ensured that the supply valve and the switching valve are prevented from being operated simultaneously. As a result, the amount of air gas to migrate to the fuel cell stack through the air supply passage and the amount of air gas to flow through the bypass passage can be adjusted after the amount of air gas introduced from the outside to the air supply passage has stabilized.

[0016] According to the third technique, it is ensured that the arm portion is in contact with the cam plate while the supply valve is closed. In other words, according to the third technique, there is no gap (no play) between the arm portion and the cam plate, and the opening degree of the valve (the supply valve, the changeover valve) can be accurately detected. The cam gear can be biased in the rotation direction (the direction in which the cam gear rotates when the supply valve is opened) by a biasing member such as a coil spring, etc., or by using the output of the motor. That is, the motor can apply torque in the rotation direction of the cam gear while the supply valve is closed.

[0017] According to the fourth technique, the structure of the air valve (cam plate) can be simplified. As described, according to the teachings disclosed in the present specification, the supply valve and the switching valve are actuated at different times (they are not actuated simultaneously). Thus, while the supply valve is not actuated (while the arm portion moves in the second range), the air valve simply needs to maintain the posture of the arm portion. With the second range having the arc shape whose distance from the rotation center of the cam plate is constant, the arm portion moves in the second range without changing its posture. Since the posture of the arm portion does not change, a structure for maintaining the engagement of the arm portion with the cam plate while the arm portion moves in the second range can be omitted, and thus the structure of the cam plate can be simplified.

[0018] According to the fifth technique, it is possible to prevent the arm portion from deviating from the cam plate (prevent the arm portion from disengaging from the cam plate) when the arm portion moves to one end of the first range (the position where the supply valve closes). Furthermore, since the fitting portion (fitting groove) is a groove recessed in the radially inward direction of the cam plate, the size of the cam plate can be reduced compared to a configuration in which the fitting portion is arranged in the circumferential direction of the cam plate.

[0019] According to the sixth technique, it is possible to reduce the change in the force applied from the cam plate to the arm portion (torque for operating the supply valve) in the early stage of opening the supply valve (for a predetermined period from the opening start).

[0020] According to the seventh technique, it is possible to control the flow rate of the air gas flowing through the air supply passage and the flow rate of the air gas flowing through the bypass passage (ratio of the flow rates) with high precision.

[0021] According to the eighth technique, it is possible to reduce the adhesion of moisture (condensation water) generated by the humidifier to the supply valve while the supply valve is closed (while the fuel cell system is not operating). It is possible to reduce corrosion of the valve body, valve seat, sealing material, etc., and also to reduce freezing of the valve body. Reducing freezing of the valve body (the valve body sticking to the valve seat) reduces the torque required to operate the valve body and reduces power consumption when the supply valve is opened.

[0022] According to the new technique, it is possible to make the discharge coefficient when the air gas flows through the air supply passage larger than the discharge coefficient when the air gas flows through the bypass passage. The air supply passage causes a larger pressure drop (passage resistance) than the bypass passage because the humidifier is arranged on the air supply passage. By making the discharge coefficient of the air supply passage larger than the discharge coefficient of the bypass passage, it is possible to reduce a difference between the flow rates of air gas flowing through the passages (the air supply passage, the bypass passage) when the opening degree of the switching valve for the passages is the same. That is, according to the ninth technique, it is possible to compensate for the pressure drop in the air supply passage due to the humidifier arranged thereon. Short description of drawings Fig. 1 shows a schematic diagram of a fuel cell system; Fig. 2 illustrates an internal structure of an air supply valve; Fig. 3 is a schematic diagram of a linkage mechanism configured to actuate valve bodies; Fig. 4 shows explanatory diagrams for operations of the air supply valve; Fig. 5 illustrates passage switching timings for an air supply passage and a bypass passage; Fig. 6 shows a schematic diagram of a fuel cell system according to a variant; Fig. 7 illustrates an internal structure of an air supply valve according to the variant; Fig. 8 shows a schematic diagram of a connection mechanism according to the variant; Fig. Figure 9 shows an enlarged view of the area shown in Fig. 8 is enclosed by a dashed line IX; and Fig. 10 represents a cross-sectional view along a line XX in Fig. 10. Description of embodiments (fuel cell system)

[0023] Referring to Fig. 1, a fuel cell system 100 is described. The fuel cell system 100 includes a fuel cell stack 20, a hydrogen system 10 that supplies hydrogen gas to the fuel cell stack 20, an air system 30 that supplies air gas (outside air) to the fuel cell stack 20, and a controller 25. In the fuel cell system 100, electricity is generated using hydrogen gas supplied by the hydrogen system 10 and oxygen gas (air gas) supplied by the air system 30. The hydrogen system 10 includes a hydrogen gas supply device 2, a hydrogen supply passage 4, and a hydrogen discharge passage 8. The hydrogen gas supply device 2 includes a hydrogen tank, a regulator, an injection device, etc. The hydrogen gas supply device 2 is controlled by the controller 25.The hydrogen gas supply device 2 supplies hydrogen gas to the fuel cell stack 20 through the hydrogen supply passage 4 based on a control signal from the controller 25. Hydrogen gas discharged from the fuel cell stack 20 (hydrogen off-gas) is discharged to the outside of the fuel cell system 100 through the hydrogen discharge passage 8. Although details will be described later, the hydrogen discharge passage 8 is connected to a diluter 42. The hydrogen off-gas is discharged to the outside of the fuel cell system 100 after being diluted in the diluter 42.

[0024] The air system 30 includes a compressor 32, an air supply passage 34, an air discharge passage 40, an FC bypass passage 36, an air supply valve 50, and an air discharge valve 38. The FC bypass passage 36 is an example of a bypass passage, and the air supply valve 50 is an example of an air valve. The compressor 32 pumps outside air as air gas to the air supply passage 34. An air purifier (not shown) is arranged upstream of the compressor 32. Thus, clean air gas is supplied to the air supply passage 34. The air supply passage 34 connects the compressor 32 to the fuel cell stack 20. The air supply valve 50 is arranged on the air supply passage 34.Specifically, the air supply passage 34 includes an upstream air supply passage 34a connecting the compressor 32 to the air supply valve 50, and a downstream air supply passage 34b connecting the air supply valve 50 to the fuel cell stack 20. When the compressor 32 is actuated and the air supply valve 50 connects the upstream air supply passage 34a to the downstream air supply passage 34b, the outside air is supplied to the fuel cell stack 20 as air gas. Details of the air supply valve 50 will be described later.

[0025] The air discharge passage 40 is connected to the fuel cell stack 20 and discharges air off-gas from the fuel cell stack 20. The air discharge passage 40 is connected to the diluter 42. In the diluter 42, the hydrogen off-gas supplied through the hydrogen discharge passage 8 is diluted by the air off-gas supplied through the air discharge passage 40. The diluted gas is discharged to the outside of the fuel cell system 100 through a discharge pipe 44. The air discharge valve 38 is arranged on the air discharge passage 40. The air discharge valve 38 is a butterfly valve and is controlled by the controller 25. By adjusting the opening degree of the air discharge valve 38, an amount of air off-gas to be supplied to the diluter 42 is adjusted, and thus the concentration of the hydrogen off-gas is adjusted.

[0026] The FC bypass passage 36 connects the air supply passage 34 to the air discharge passage 40. Specifically, one end of the FC bypass passage 36 is connected to the air supply valve 50, and the other end thereof is connected to the air discharge passage 40 at a position downstream of the air discharge valve 38. When the air supply valve 50 connects the air supply passage 34 (the upstream air supply passage 34a) to the FC bypass passage 36, the air gas in the air supply passage 34 is supplied to the air discharge passage 40. The FC bypass passage 36 is a passage that bypasses the fuel cell stack 20 and connects the air supply passage 34 to the air discharge passage 40. (air supply valve)

[0027] Referring to Fig. 2 and Fig. 3 the air supply valve 50 is described. Fig. 2 illustrates an internal structure of the air supply valve 50 (air flow section 52). Fig. 3 illustrates a valve actuator 70 that actuates valve bodies 60, 64 in the air flow section 52. The valve actuator 70 is an example of a linkage mechanism. As shown in Fig. 2 and Fig. As shown in Figure 3, the air supply valve 50 includes the air flow section 52 through which the air gas supplied from the compressor 32 flows, the valve bodies 60, 64 that change flow passages in the air flow section 52, and the valve actuator 70 that actuates the valve bodies 60, 64. The valve actuator 70 is disposed outside the air flow section 52. First, the structure in the air flow section 52 will be described.

[0028] As in Fig. As shown in Fig. 2, the air flow portion 52 includes a tubular first flow portion 52a connected to the upstream air supply passage 34a and a tubular second flow portion 52b. One end of the second flow portion 52b is connected to the downstream air supply passage 34b, and the other end is connected to the FC bypass passage 36. A flange 53a is formed at one end of the first flow portion 52a and is connected to the upstream air supply passage 34a. The other end of the first flow portion 52a is connected to an axially intermediate portion of the second flow portion 52b, specifically, to an axially intermediate portion of the second flow portion 52b. The first flow portion 52a and the second flow portion 52b are connected to each other, and their cross-sectional shape (flow passage shape) is substantially T-shaped.

[0029] The first valve body 60 is arranged on the other end side of the first flow section 52a. The first valve body 60 is an example of a supply valve. The first valve body 60 is connected to a first shaft 62 and rotates with rotation of the first shaft 62. The first valve body 60 can control the flow rate of the air gas to be supplied from the first flow section 52a to the second flow section 52b. That is, by rotating the first valve body 60, the flow rate of the air gas flowing through the first flow passage 54 in the first flow section 52a (flow rate of the air gas to be supplied to the second flow section 52b) can be varied. The first valve body 60 can be regarded as a valve that varies the total flow rate of the air gas to be supplied to the downstream air supply passage 34b and the FC bypass passage 36, which will be described later.

[0030] A flange 53b is formed at one end of the second flow portion 52b and is connected to the downstream air supply passage 34b. A flange 53c is formed at the other end of the second flow portion 52b and is connected to the FC bypass passage 36. The second valve body 64 is arranged at the middle portion of the second flow portion 52b. The second valve body 64 is an example of a switching valve. The second valve body 64 is connected to a second shaft 66 and rotates with rotation of the second shaft 66. The second valve body 64 can control the flow direction of the air gas supplied to the second flow portion 52b from the first flow portion 52a. The air supply valve 50 can be considered to include both a supply valve (the first valve body 60) and a switching valve (the second valve body 64).

[0031] When the second valve body 64 is in the state shown in Fig. 2 is indicated by the solid line, the air gas supplied to the second flow section 52b from the first flow section 52a flows through a second flow passage 56 and the downstream air supply passage 34b and is then supplied to the fuel cell stack 20. When the second valve body 64 is in the state shown in Fig. 2 is indicated by the dashed line, the air gas supplied to the second flow section 52b from the first flow section 52a flows through a third flow passage 58 and the FC bypass passage 36 and is then supplied to the air discharge passage 40 (see also Fig. 1). When the second valve body 64 is controlled to occupy a position intermediate between the solid line and the dashed line, the air gas can be supplied to both the fuel cell stack 20 and the air discharge passage 40. The second valve body 64 can be considered a valve that varies a percentage of air gas to be directly supplied to the fuel cell stack 20 from the air gas supplied to the air supply valve 50 from the compressor 32. (valve actuator)

[0032] As in Fig. 3, the valve actuator 70 is arranged outside the air flow section 52. In Fig. In Figure 3, the internal structure of the airflow section 52 (the valve bodies 60, 64, the flow passages 54, 56, 58) is indicated by dashed lines. The valve actuator 70 is housed in the same housing (not shown) in which the airflow section 52 is housed. The valve actuator 70 includes a motor gear 72 mounted on an output shaft of a motor (not shown), a first gear 74, a second gear 76, a cam (cam plate) 78, a first arm 82, and a second arm 84. The second gear 76 is an example of a cam gear. The first gear 74 is a dual gear in which a large-diameter gear 74a meshes with the motor gear 72, and a small-diameter gear 74b meshes with the second gear 76. The second gear 76 is attached to the cam 78.The number of teeth of the large-diameter gear 74a is greater than the number of teeth of the motor gear 72, and the number of teeth of the second gear 76 is greater than the number of teeth of the small-diameter gear 74b. Thus, the output torque of the motor can be increased (the speed of the motor can be reduced) by the motor gear 72, the first gear 74, and the second gear 76. The use of the gears 74, 76 allows the motor to actuate (rotate) the cam 78 even when the motor is small (low torque).

[0033] The cam 78 has a cam groove 78a, and a roller 80 is arranged in the cam groove 78a. The roller 80 is movable along the cam groove 78a and is rotatably supported on the first arm 82. The roller 80 and the first arm 82 are an example of an arm portion. The first arm 82 is fixed to the first shaft 62 and rotates in response to the movement (rotation) of the cam 78. When the first arm 82 rotates, the first shaft 62 rotates and the first valve body 60 rotates. The first arm 82 rotates in response to the rotation of the cam 78 until the cam 78 rotates a predetermined angle, whereas it does not rotate even if the cam 78 rotates after the rotation angle of the cam 78 exceeds the predetermined angle.Specifically, the first arm 82 rotates in response to the rotation of the cam 78 until the first valve body 60 rotates to shift from a state where the first valve body 60 closes the first flow passage 54 to a state where the first valve body 60 opens (fully opens) the first flow passage 54, whereas the first arm 82 does not rotate even if the cam 78 rotates after the first valve body 60 shifts to the state where it opens the first flow passage 54. That is, the first valve body 60 does not rotate after the rotation angle of the cam 78 exceeds the predetermined angle. The cam 78 has a second-arm actuating portion 78b for actuating the second arm 84, which will be described later.

[0034] The second arm 84 is fixed to the second shaft 66. The rotation axis of the second arm 84 (the second shaft 66) is the same as the rotation axis of the second gear 76. However, the second arm 84 is not fixed to the second gear 76 (nor to the cam 78, which is fixed to the second gear 76). Therefore, the second arm 84 does not rotate integrally with the second gear 76 or the cam 78. However, the second arm 84 rotates with the rotation of the cam 78 after the rotation angle of the cam 78 exceeds the predetermined angle. When the second arm 84 rotates, the second shaft 66 rotates and the second valve body 64 rotates. The valve actuator 70 actuates the first arm 82 and the second arm 84 with a single motor, without using separate motors to actuate the first arm 82 and the second arm 84.

[0035] The second arm 84 has a contact portion 84a configured to contact the second-arm actuating portion 78b. When the second gear 76 (the cam 78) rotates by the predetermined angle and the second-arm actuating portion 78b contacts the contact portion 84a, the second arm 84 rotates with the rotation of the second gear 76 (the cam 78). In particular, as shown in Fig. 3, when the first valve body 60 closes the first flow passage 54, the second-arm actuating portion 78b is offset from the contact portion 84a by an angle α1 with respect to the second shaft 66 (the rotational axis of the second gear 76). Thus, the second arm 84 (the second valve body 64) does not rotate until the second gear 76 (the cam 78) rotates by the angle α1, whereas it begins to rotate as soon as the rotational angle of the second gear 76 exceeds the angle α1. The second arm 84 is biased by a spring (not shown) such that the second valve body 64 is in the state shown in Fig. 3 (in the state where the second valve body 64 fully opens the second flow passage 56). Therefore, while the second-arm operating portion 78b is not in contact with the contact portion 84a, the second flow passage 56 is fully open. Next, an operation of the air supply valve 50 (how the first valve body 60 and the second valve body 64 move when the valve actuator 70 is operating) will be described in detail. (Operation of air supply valve)

[0036] Referring to Fig. 4, an operation 90 of the air supply valve 50 is described. In Fig. 4 are the gears 72, 74 in Fig. 3 is not shown. A state (A) represents a state in which the air supply valve 50 is closed. That is, in the state (A), the first valve body 60 closes the first flow passage 54, the air gas does not flow through the second flow passage 56 or the third flow passage 58, and the air gas is not supplied to the downstream air supply passage 34b or the FC bypass passage 36 (neither the fuel cell stack 20 nor the air discharge passage 40).

[0037] A state (B) represents a state in which the second gear 76 (the cam 78) has rotated by the angle α1 (see Fig. 3), the roller 78 has moved within the cam groove 78a, and the first valve body 60 has rotated so that the first flow passage 54 is fully open. In state (B), the second-arm actuating portion 78b is in contact with the contact portion 84a. Therefore, as the second gear 76 continues to rotate, the second arm 84 rotates, and the second valve body 64 rotates. In other words, during the transition from state (A) to state (B), the second flow passage 56 is open and the third flow passage 58 is closed because the second valve body 64 is not rotating. Thus, during the transition from state (A) to state (B), the air gas is only supplied to the downstream air supply passage 34b and is not supplied to the FC bypass passage 36. That is,, during the transition from the state (A) to the state (B), the air gas supplied to the air supply valve 50 from the compressor 32 is supplied only to the fuel cell stack 20.

[0038] A state (C) represents a state in which the second arm 84 (the second valve body 64) has rotated with the second gear 76 (the cam 78) so that the second flow passage 56 is closed and the third flow passage 58 is fully open. In the state (C), the air gas is supplied only to the FC bypass passage 36 and is not supplied to the downstream air supply passage 34b. That is, in the state (C), the air gas supplied to the air supply valve 50 from the compressor 32 is supplied only to the air discharge passage 40. During the transition from the state (B) to the state (C), the first valve body 60 does not rotate and the first flow passage 54 remains fully open.Therefore, during the transition from state (B) to state (C), the flow rate of the air gas flowing through the first flow passage 54 (the total flow rate of the air gas flowing through the second flow passage 56 and the third flow passage 58) does not change, whereas the ratio of the flow rate of the air gas supplied to the fuel cell stack 20 and the flow rate of the air gas supplied to the air discharge passage 40 changes.

[0039] In the air supply valve 50, the state of the air supply valve 50 transitions from the state (A) through the state (B) to the state (C) in this order with the rotation of the single motor.Thus, in the air supply valve 50, the use of only one motor allows switching under the following states for the downstream air supply passage 34b and the FC bypass passage 36: the state in which the downstream air supply passage 34b and the FC bypass passage 36 are both closed (the state (A)); the state in which only the downstream air supply passage 34b is open and the FC bypass passage 36 is closed (from the state (A) to the state (B)); the state in which the downstream air supply passage 34b and the FC bypass passage 36 are both open and the ratio of the air gas flowing through the two passages 34b, 36 changes (from the state (B) to the state (C)); and the state in which only the FC bypass passage 36 is open and the downstream air supply passage 34b is closed (the state (C)).

[0040] As described, during the transition from state (B) to state (C), the roller 80 moves within the cam groove 78a while the second gear 76 (the cam 78) rotates, whereas the first arm 82 does not rotate. This occurs because the distance from the rotational axis of the second gear 76 (the cam 78) to the roller 80 does not change during the transition from state (B) to state (C) (since the cam groove 78a in which the roller 80 moves is on an arc of the rotational axis of the second gear 76). In contrast, during the transition from state (A) to state (B), the first arm 82 rotates while the roller 80 moves. This occurs because the distance from the rotational axis of the second gear 76 (the cam 78) to the roller 80 (the position of the cam groove 78a in which the roller 80 moves) gradually increases during the transition from state (A) to state (B). That is,, in the valve actuator 70, the cam groove 78a is formed to cause the roller 80 to move away from the rotational axis of the second gear 76 until the second gear 76 (the cam 78) rotates by the angle α1, and also to cause the roller 80 to be positioned at a constant distance from the rotational axis of the second gear 76 after the second gear 76 (the cam 78) has rotated by the angle α1.

[0041] The timings when the first valve body 60 and the second valve body 64 are actuated can be adjusted by changing the shape of the cam groove 78a. For example, it is possible to prevent the second valve body 64 from moving for a predetermined period of time (a period during which the second gear 76 rotates by a predetermined rotation angle) after the first valve body 60 has fully opened. Alternatively, adjustment may be made such that the second valve body 64 starts moving before the first valve body 60 fully opens (while the opening degree of the first valve body 60 increases). The timings when the first valve body 60 and the second valve body 64 are actuated can also be adjusted by changing the angle α1 between the second-arm actuating portion 78b and the contact portion 84a without changing the shape of the cam groove 78a. That is,, the timings when the first valve body 60 and the second valve body 64 are actuated can be adjusted more easily than changing the shape of the cam groove 78a. Hereinafter, as a variation of the valve actuator 70, the timings when the first valve body 60 and the second valve body 64 are actuated are adjusted by changing the angle α1 between the second-arm actuating portion 78b and the contact portion 84a to an angle α. (Variant)

[0042] A variant 92 of Fig. 5 illustrates relationships between rotation angles θ of the second gear 76 and flow rates of air gas supplied to the downstream air supply passage 34b and the FC bypass passage 36 (flow rates of air gas flowing through the second flow passage 56 and the third flow passage 58). Lines 94 indicate flow rates of air gas flowing through the second flow passage 56 (flow rates of air gas to be supplied to the fuel cell stack 20), and lines 96 indicate flow rates of air gas flowing through the third flow passage 58 (flow rates of air gas to be supplied to the air discharge passage 40) (see also Fig. 1, Fig. 2).

[0043] Example (a) shows a case where the angle α between the second-arm operating portion 78b and the contact portion 84a is smaller than the angle α1, example (b) shows a case where the angle α is equal to the angle α1 (i.e., the valve actuator 70), and example (c) shows a case where the angle α is greater than the angle α1. An angle θ0 is an angle at which the first valve body 60 closes the first flow passage 54 (corresponding to the state (A) in Fig. 4). An angle θ1 is an angle at which the opening degree of the first valve body 60 is its maximum, and the total flow rate of the air gas flowing through the second flow passage 56 and the third flow passage 58 is its maximum (corresponding to the state (B) in Fig. 4). An angle θ2 is an angle at which the second valve body 64 closes the second flow passage 56 and only opens the third flow passage 58 (corresponding to the state (C) in Fig. 4).

[0044] In example (a), when the second gear 76 rotates from its initial state (from the angle θ0) by the angle θ1, the opening degree of the first valve body 60 reaches the maximum, and the flow rate of the air gas flowing through the second flow passage 56 (the line 94) reaches the maximum. Between the angle θ0 and the angle θ1, the flow rate of the air gas flowing through the second flow passage 56 increases while the opening degree of the first valve body 60 increases. In example (a), the second-arm operating portion 78b does not contact the contact portion 84a even when the second gear 76 rotates by the angle θ1 (see state (B) in Fig. 4 for comparison). Therefore, even when the rotation angle of the second gear 76 reaches the angle θ1, the second valve body 64 does not begin to rotate, and the flow rate of the air gas flowing through the third flow passage 58 is "zero." The second valve body 64 begins to rotate after the rotation angle of the second gear 76 reaches the angle α. Between the angle α and the angle θ2, the flow rate of the air gas flowing through the second flow passage 56 decreases, and the flow rate of the air gas flowing through the third flow passage 58 (the line 96) increases. Then, when the rotation angle of the second gear 76 reaches the angle θ2, the air gas flows only through the third flow passage 58.

[0045] In example (a), switching between the second flow passage 56 and the third flow passage 58 is performed after the flow rate of the air gas introduced to the air supply valve 50 (the flow rate in the first flow passage 54) has been stabilized. Thus, example (a) facilitates the control of the ratio of the flow rate of the air gas to be supplied to the downstream air supply passage 34b and the flow rate of the air gas to be supplied to the FC bypass passage 36. Furthermore, since the period during which the air gas flows only through the second flow passage 56 can be extended, it is possible to supply the maximum amount of air gas to the fuel cell stack 20 without controlling the rotation angle of the second gear 76 with high precision.

[0046] Example (b) corresponds to the valve actuator 70. When the rotation angle of the second gear 76 reaches the angle α (the angle α1), the opening degree of the first valve body 60 reaches the maximum, and the second valve body 64 starts to rotate. Thus, when the flow rate of the air gas flowing through the second flow passage 56 (the line 94) reaches the maximum, switching between the second flow passage 56 and the third flow passage 58 begins. That is, immediately after the flow rate of the air gas flowing through the first flow passage 54 reaches the maximum, control begins over the ratio of the flow rate of the air gas to be supplied to the downstream air supply passage 34b and the flow rate of the air gas to be supplied to the FC bypass passage 36 (the line 96).The example (b) is highly responsive to the flow passage switching (adjustment in the amount of air gas to be supplied to the downstream air supply passage 34b and the amount of air gas to be supplied to the FC bypass passage 36) in response to the rotation of the second gear 76 (driving the motor).

[0047] In example (c), when the rotation angle of the second gear 76 reaches the angle α, the second valve body 64 begins to rotate before the opening degree of the first valve body 60 reaches the maximum (before the rotation angle of the second gear 76 reaches the angle θ1). During a period from when the rotation angle of the second gear 76 reaches the angle α until it reaches the angle θ1, the flow rate of the air gas flowing through the second flow passage 56 (the line 94) remains constant, whereas the flow rate of the air gas flowing through the third flow passage 58 (the line 96) increases. After the angle θ1, the flow rate of the air gas flowing through the second flow passage 56 decreases, whereas the flow rate of the air gas flowing through the third flow passage 58 increases.Example (c) is useful when the flow rate of the air gas to be supplied to the downstream air supply passage 34b (the fuel cell stack 20) ​​needs to be limited.

[0048] As described, in the fuel cell system 100, the flange 53b is connected to the downstream air supply passage 34b, and the flange 53c is connected to the FC bypass passage 36. However, the flange 53b may be connected to the FC bypass passage 36, and the flange 53c may be connected to the downstream air supply passage 34b. In this case, when the engine starts, the state of the fuel cell system 100 transitions in the following order: a state in which both the downstream air supply passage 34b and the FC bypass passage 36 are closed; a state in which only the FC bypass passage 36 is open and the downstream air supply passage 34b is closed; a state in which both the downstream air supply passage 34b and the FC bypass passage 36 are open; and and a state in which only the downstream air supply passage 34b is open and the FC bypass passage 36 is closed. (Variant of the fuel cell system)

[0049] Referring to Fig. 6, a fuel cell system 200 is described. The fuel cell system 200 is a variant of the fuel cell system 100. Thus, elements of the fuel cell system 200 that are substantially the same as the elements of the fuel cell system 100 are denoted by the same reference numerals as those of the fuel cell system 100 or by reference numerals whose last two digits are the same as those of the fuel cell system 100, and a description thereof may be omitted. In the fuel cell system 200, a humidifier 37 is disposed in an air system 30. Further, an air supply valve 150 is disposed on an air supply passage 34, an air discharge valve 38 is disposed on an air discharge passage 40, and a bypass valve 39 is disposed on an FC bypass passage 36.

[0050] The humidifier 37 is arranged on the air supply passage 34 and the air discharge passage 40. Specifically, the humidifier 37 is connected to the air supply passage 34 at a position between the air supply valve 150 and a fuel cell stack 20, and is connected to the air discharge passage 40 at a position between the fuel cell stack 20 and the air discharge valve 38. The humidifier 37 adjusts a humidity (moisture content) of air to be supplied to the fuel cell stack 20 and a humidity of air off-gas to be supplied to a diluter 42.

[0051] A humidifier bypass passage 35 is connected to the air supply passage 34 (downstream air supply passage 34b). The humidifier bypass passage 35 is an example of a bypass passage. The humidifier bypass passage 35 bypasses the diluter 42 and is connected to the air supply passage 34 (downstream air supply passage 34b) at a position upstream of the diluter 42 and at a position downstream thereof. Specifically, in the fuel cell system 200, one end (upstream end) of the humidifier bypass passage 35 is connected to the air supply valve 150 (an example of an air valve). When the air supply valve 150 connects the air supply passage 34 (the downstream air supply passage 34b) with the humidifier bypass passage 35, air gas supplied to the air supply passage 34 is supplied to the fuel cell stack 20 without passing through the humidifier 37.On the other hand, when the air supply valve 150 communicates with the downstream air supply passage 34b, air gas supplied to the air supply passage 34 is supplied to the fuel cell stack 20 through the humidifier 37. (Variant of the air supply valve)

[0052] Referring to Fig. 7 to 10, the air supply valve 150 will be described. The air supply valve 150 is a warning variant of the air supply valve 50. Thus, elements of the air supply valve 150 that are substantially the same as the elements of the air supply valve 50 are denoted by the same reference numerals as those of the air supply valve 50, or by reference numerals whose last two digits are the same as those of the air supply valve 50, and a description thereof may be omitted. In the fuel cell system 200, the air supply valve 50 may be used instead of the air supply valve 150. In this case, the flange 53b may be connected to the downstream air supply passage 34b, and the flange 53c may be connected to the humidifier bypass passage 35. Alternatively, the flange 53b may be connected to the humidifier bypass passage 35, and the flange 53c may be connected to the downstream air supply passage 34b.

[0053] Fig. 7 illustrates the internal structure of the air supply valve 150. In the air supply valve 150, a flange 53b is connected to the humidifier bypass passage 35, and a flange 53c is connected to the downstream air supply passage 34b (see Fig. 2 for comparison). In Fig. 7, a state in which the air supply valve 150 is closed (air gas is not supplied to the fuel cell stack 20) ​​is indicated by solid lines, and a state in which a first valve body 60 has rotated (the air supply valve 150 is open) and a state in which a second valve body 64 has rotated (passage through which air gas flows has been switched) are indicated by dashed lines.

[0054] As in Fig. As shown in Fig. 7, in the state where the air supply valve 150 is closed (the first valve body 60 is closed), the second valve body 64 is in contact with an inner wall of a second flow portion 52b to block the air supply passage 34 (the downstream air supply passage 34b) between the first valve body 60 and the humidifier 37. The air supply valve 150 therefore prevents moisture generated in the humidifier 37 from adhering to the first valve body 60 when the fuel cell system 200 is not operating.

[0055] In the air supply valve 150, when the first valve body 60 is fully open (in the state indicated by the dashed lines), a downstream end of the first valve body 60 is closer to the flange 53b (side connected to the downstream air supply passage 34b) than an upstream end thereof. This makes a discharge coefficient when the air gas flows through the downstream air supply passage 34b (when the second valve body 64 is in the solid line state) larger than a discharge coefficient when the air gas flows through the humidifier bypass passage 35 (when the second valve body 64 is in the dashed line state). The air gas experiences a pressure drop by flowing through the humidifier 37.The above configuration can reduce the difference between the fluid pressure when the air gas flows through the downstream air supply passage 34b and the fluid pressure when the air gas flows through the humidifier bypass passage 35, and thus improves bypass control while the second valve body 64 is actuated.

[0056] Fig. 8 illustrates a valve actuator 170 configured to actuate the valve bodies 60, 64. The valve actuator 170 is an example of a linkage mechanism. In the valve actuator 170, a second gear 176 meshes with a small-diameter gear 74b of a first gear 74. The second gear 176 is fixed to a cam 178 (an example of a cam plate). A magnet 65 is disposed on a surface of the second gear 176. The magnet 65 opposes a rotation angle detection sensor (not shown). The rotation angle detection sensor detects the rotation angle of the second gear 176. Furthermore, a support member 182 supporting an arm portion 181 is fixed to a first shaft 62. A roller 80 is rotatably supported at one end of the arm portion 181.

[0057] The cam 178 includes a fitting portion 179 into which the roller 80 is fitted when the air supply valve 150 is closed, and a guide portion 180 along which the roller 80 moves while contacting it when the air supply valve 150 is open (when the first valve body 60 or the second valve body 64 is actuated). The fitting portion 179 is a groove formed by a part of the circumference of the cam 178 that is recessed in a radially inward direction of the cam 178. The fitting portion 179 prevents the roller 80 from deviating from the cam 178 when the air supply valve 150 is closed (when the first valve body 60 is closed). The second gear 176 is biased in the direction indicated by an arrow 55 (in a direction that causes the air supply valve 150 to open) while the air supply valve 150 is closed.Thus, the roller 80 is held in contact with a wall surface of the fitting portion 179. A contact portion is disposed on a rear surface of the second gear 176, although not shown. The contact portion is mounted on a second shaft 66 and contacts the second gear 176 (the cam 178) when the second gear 176 (the cam 178) rotates by a predetermined angle.

[0058] A basic operation of the valve actuator 170 is essentially the same as that of the valve actuator 70. That is, when the second gear 176 (the cam 178) rotates, the first shaft 62 rotates and the first valve body 60 is actuated, while the roller 80 moves in a first region 191 where the distance from the rotational axis of the second gear 176 to the roller 80 gradually increases. Further, the first shaft 62 does not rotate and the first valve body 60 is not actuated, while the roller 80 moves in a second region 192 where the distance from the rotational axis of the second gear 176 is constant. While the roller 80 moves in the second region 192, the second shaft 66 rotates and the second valve body 64 is actuated. In the valve actuator 170, a third region 193 is arranged between the first region 191 and the second region 192.The third region 193 is not involved in the operation of the first valve body 60 or the operation of the second valve body 64. The third region 193 can be formed by adjusting the position of the above-described contact portion mounted on the second shaft 66.

[0059] Referring to Fig. 9, the first region 191, the second region 192, and the third region 193 will be described. The first region 191 is a region from an inner surface of the fitting portion 179 (a surface thereof closer to the rotational axis of the cam 178 (the second gear 176)) to a position where the distance from the rotational center of the cam 178 becomes constant. In the first region 191, its curvature is not constant, and the distance from the rotational center of the cam 178 varies. The second region 192 is independent (separate) from the first region 191 and has an arc shape whose distance from the rotational center of the cam 178 is constant. That is, the second region 192 has a constant curvature.The third portion 193 has an arc shape whose distance from the rotation center of the cam 178 is constant, and the length of the third portion 193 can be adjusted to adjust the timing when the second valve body 64 begins to move with the rotation of the second gear 176, as described above. As shown in FIG. Fig. 8 and Fig. As clearly shown in Figure 9, the length of the second region 192 is longer than the length of the first region 191.

[0060] The first region 191 includes a straight portion 191a and a curved portion 191b. The curved portion 191b is located between the straight portion 191a and the third region 193. While the valve actuator 70 is closed, the arm portion 181 (the roller 80) is in contact with the straight portion 191a. When the valve actuator 70 is started, the arm portion 181 (the roller 80) first moves along the straight portion 191a while maintaining contact with the first region 191. This stabilizes a force applied to the arm portion 181 (the roller 80) at an early stage after the valve actuator 70 is started (within a predetermined period of time from the start of the valve actuator 70). That is, a torque for operating the first valve body 60 is stabilized.For example, if the entire first portion 191 is curved, it is necessary to control the machining accuracy of the cam 178 with high precision to stabilize the force exerted on the arm portion 181 in the early stage after the valve actuator 70 is started (to reduce dimensional variation). The first portion 191 having the straight portion 191a facilitates the machining of the first portion 191 and easily stabilizes the drive torque for the first valve body 60.

[0061] Fig. 10 illustrates a cross-sectional view of the second gear 176. As described, the second gear 176 is biased in the direction of arrow 55 while the air supply valve 150 is closed (see also Fig.8). A coil spring 196 is arranged on the rear surface of the second gear 176. One end of the coil spring 196 is fixed to a protruding portion 177 on the rear surface of the second gear 176, and the other end thereof is fixed to a protruding portion 194 of a housing 190 of the air supply valve 150. The second gear 176 is biased by the coil spring 196 in the direction of arrow 55. Positioning the coil spring 196 between the second gear 176 and the housing 190 prevents the second gear 176 from moving in a direction of the rotation axis. The distance between the magnet 65 and the rotation angle detection sensor (not shown) is thereby stabilized, and the rotation angle of the second gear 176 can be accurately detected. (Other embodiments)

[0062] The above embodiments describe an example in which one end of the bypass passage is connected to the air supply passage and the other end thereof is connected to the air discharge passage, and an example in which one end of the bypass passage is connected to the air supply passage at a position upstream of the humidifier and the other end thereof is connected to the air supply passage at a position downstream of the humidifier. However, the bypass passage (the other end thereof) does not necessarily have to be connected as described in the embodiments.What is important in the teachings disclosed herein is that a single air valve (air supply valve) performs switching between a state in which the air supply passage and the bypass passage are both closed, a state in which the air supply passage is open and the bypass passage is closed, and a state in which the air supply passage is closed and the bypass passage is open.

[0063] Other important points in the teachings disclosed herein are that the supply valve configured to open and close the air supply passage and the switching valve configured to switch the air supply passage and the bypass passage are operated by the arm portion attached to the supply valve and the link mechanism including the cam plate attached to the switching valve, and that the link mechanism includes the guide portion including the first region where the arm portion moves for the opening / closing movement of the supply valve and the second region where the arm portion moves for the opening / closing movement of the switching valve, the second region being independent of the first region. Thus, the first region and the second region may be adjacent to each other, for example. That is,It is not always necessary to place the third section, where neither the opening / closing movement of the supply valve nor the opening / closing movement of the switching valve occurs, between the first section and the second section. Without the third section, the size of the cam plate can be reduced.

[0064] Apart from a coil spring, a biasing member such as a leaf spring, a rubber block, etc. may be used to bias the cam gear (second gear) in the direction in which the cam gear rotates when the supply valve is opened. Alternatively, the biasing member may be omitted, and the cam gear may be biased by the motor applying torque to the cam gear in the direction in which the cam gear rotates when the supply valve is opened while the supply valve is closed. Alternatively, the biasing member may be omitted, and a shape(s) of the cam plate and / or the arm portion for preventing a positional change of the cam plate and the roller (arm portion) while the air supply valve is closed may be changed.

[0065] The configuration of the cam plate is not limited to those described in the embodiments. For example, the fitting portion configured to fit with the roller (arm portion) when the supply valve is closed, the straight portion of the first portion, etc., may be omitted if necessary. The length of the first portion may be longer than the length of the second portion, so that the actuation speed of the supply valve is made slower than that of the switching valve.

Claims

[1] An air valve (50, 150) arranged in an air system (30) of a fuel cell stack (20) and configured to control a flow of air gas to be supplied to the fuel cell stack (20), comprising: a supply valve (60) adapted to form an air supply passage (34, 34a, 34b), to open and close through which the air gas to be supplied to the fuel cell stack (20) from the outside flows; a switching valve (64) configured to switch between a state in which the air gas supplied from the outside flows through the air supply passage (34, 34a, 34b) and a state in which the air gas supplied from the outside flows through a bypass passage (35, 36), in which the bypass passage (35, 36) branches off from the air supply passage (34, 34a, 34b) and bypasses a component arranged downstream of the air valve (50, 150); and a connecting mechanism (70, 170) connected to the supply valve (60) and the switching valve (64) and designed to actuate the supply valve (60) and the switching valve (64), wherein the connecting mechanism (70, 170) comprises: an arm portion (80, 82, 181) attached to the supply valve (60); and a cam plate (78, 178) having a guide portion (180) with which the arm portion (80, 82, 181) is to be contacted, in which the guide section (180) comprises: a first region (191) which is a region where the arm portion (80, 82, 181) moves for an opening / closing movement of the supply valve (60); and a second region (192) which is independent of the first region (191) and is a region where the arm portion (80, 82, 181) moves for an opening / closing movement of the changeover valve (64). [2] Air valve (50, 150) according to claim 1, wherein a third region (193) is arranged between the first region (191) and the second region (192), and the third region (193) is a region where neither the opening / closing movement of the supply valve (60) nor the opening / closing movement of the changeover valve (64) is carried out. [3] Air valve (50, 150) according to claim 1 or 2, wherein the cam plate (78, 178) is attached to a cam gear (76, 176) connected to a motor, and the cam gear (76, 176) is biased in a direction in which the cam gear (76, 176) rotates when the supply valve (60) is opened, so that the arm portion (80, 82, 181) is in contact with the first region (191) while the supply valve (60) is closed. [4] Air valve (50, 150) according to one of claims 1 to 3, in which the second region (192) has a contact portion having an arc shape whose distance from a center of rotation of the cam plate (78, 178) is constant, and the arm portion (80, 82, 181) moves into contact with the contact portion while the changeover valve (64) is actuated. [5] Air valve (150) according to one of claims 1 to 4, in which the cam plate (178) has a fitting portion (179) adapted to fit with the arm portion (80, 181) when the supply valve (60) is closed, and the fitting portion (179) is a groove recessed in a radially inward direction of the cam plate (178). [6] The air valve (150) according to any one of claims 1 to 5, wherein the first region (191) has a straight portion (191a) configured to contact the arm portion (80, 181) while the supply valve (60) is closed, and the straight portion (191a) is maintained in a contact state with the arm portion (80, 181) for a predetermined period of time from an opening start of the supply valve (60). [7] The air valve (50, 150) according to any one of claims 1 to 6, wherein a length of the second portion (192) is longer than a length of the first portion (191). [8] Fuel cell system (200) with the air valve (150) according to one of claims 1 to 7, in which a humidifier (37) is arranged between the air valve (150) and the fuel cell stack (20), the bypass passage (35) is connected to the air supply passage (34, 34a, 34b) and bypasses the humidifier (37), and the switching valve (64) contacts an inner wall of the air supply passage (34, 34a, 34b) to block the air supply passage (34, 34a, 34b) between the supply valve (60) and the humidifier (37) when the supply valve (60) is closed. [9] Fuel cell system (200) with the air valve (150) according to one of claims 1 to 7, in which a humidifier (37) is arranged between the air valve (150) and the fuel cell stack (20), the bypass passage (35) is connected to the air supply passage (34, 34a, 34b) and bypasses the humidifier (37), and the air valve (150) has: a tubular first flow section (52a) connected to the air supply passage (34a) at a position upstream of the supply valve (60); and an air flow section (52) having one end connected to the air supply passage (34b) at a position downstream of the supply valve (60), another end connected to the bypass passage (35), and an intermediate portion connected to the first flow section (52a), and a downstream end of the supply valve (60) is closer to one end of the air flow section (52) than an upstream end of the supply valve (60) when the supply valve (60) is fully open.

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