Sensor mounting device

Abstract

To improve the detection accuracy of sensors used in fuel cells. [Solution] The sensor mounting device 101 comprises a connecting pipe 20 made of an insulating material that forms a gas flow path through which reaction gas for a fuel cell flows, a spacer member 30 made of a conductive material that is fitted into a hole provided in the connecting pipe 20, a pressure sensor 15 attached to the spacer member 30, and a ground wire attached to the spacer member. The spacer member 30 has one end with a communication opening that is placed in the hole and the other end with a sensor mounting portion to which the pressure sensor 15 is attached, and extends substantially upward from one end to the other, forming a closed space that communicates with the gas flow path through the communication opening.

Description

Technical Field

[0001] The present invention relates to a sensor mounting device for mounting a sensor used in a fuel cell.

Background Art

[0002] In recent years, in order to enable more people to have access to affordable, reliable, sustainable, and advanced energy, technological development related to fuel cells that contribute to energy efficiency has been carried out. As a mounting structure for sensors used in this type of fuel cell, conventionally, a structure has been known in which a sensor is grounded via an earth wire to prevent abnormal sensor output due to electrostatic charging (see, for example, Patent Document 1). In the structure described in Patent Document 1, a sensor is attached to an insulating resin pipe, and a plate-shaped attachment member made of metal to which an earth wire is connected is provided by connecting to a metal sensor body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the structure described in Patent Document 1 above, since the tip of the sensor is located along the inner wall surface of the insulating resin pipe, water vapor or the like contained in the gas passing through the pipe may adhere to the tip of the sensor, which may deteriorate the detection accuracy of the sensor.

Means for Solving the Problems

[0005] A sensor mounting device according to one aspect of the present invention comprises a flow path forming member made of an insulating material that forms a gas flow path for reaction gas for a fuel cell, a spacer member made of a conductive material that is attached to a connection hole provided in the flow path forming member, a sensor attached to the spacer member, and a ground wire attached to the spacer member. The spacer member has one end provided with a communication opening that is placed in the connection hole, and the other end provided with a sensor mounting portion to which the sensor is attached, and extends substantially upward from one end to the other, and is configured to form a closed space that communicates with the gas flow path through the communication opening. The other end of the spacer member has a pair of sensor mounting portions, and the ground wire is positioned between the pair of sensor mounting portions. [Effects of the Invention]

[0006] According to the present invention, the detection accuracy of sensors used in fuel cells can be improved. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing a part of the configuration of a fuel cell system to which a sensor mounting device according to an embodiment of the present invention is applied. [Figure 2] Figure 1 shows a schematic diagram illustrating the configuration of the ejector included in the fuel cell system. [Figure 3] Figure 1 is a perspective view showing the external shape of the fuel gas supply and discharge section included in the fuel cell system. [Figure 4] An exploded perspective view showing the main components of a sensor mounting device according to an embodiment of the present invention. [Figure 5] A perspective view showing the external shape of a sensor mounting device according to an embodiment of the present invention. [Figure 6] A cross-sectional view of the main part of the sensor mounting device along the line VI-VI in Figure 4. [Figure 7] A cross-sectional view of the main part of the sensor mounting device along the line VII-VII in Figure 4. [Figure 8] A cross-sectional view of the main part of the sensor mounting device along a vertical plane passing through a predetermined axis in Figure 4. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to Figures 1 to 8. The sensor mounting device according to the embodiment of the present invention is applied to a fuel cell. A fuel cell is configured to generate electricity through an electrochemical reaction between a fuel gas containing hydrogen and an oxidizer gas containing oxygen. The fuel gas and oxidizer gas are sometimes collectively referred to as reaction gases. The sensor mounting device is used to attach a sensor that detects the physical quantities (temperature and pressure) of the reaction gas to a fuel cell. Below, as an example of a sensor mounting device, the configuration of the mounting part for a pressure sensor that detects the pressure of the fuel gas will be described.

[0009] Figure 1 is a schematic diagram showing the configuration of a fuel cell system 100 to which a sensor mounting device according to an embodiment of the present invention is applied. The fuel cell system 100 is mounted, for example, on a vehicle and generates electricity for driving the vehicle. Figure 1 mainly shows the configuration relating to the flow of fuel gas. As shown in Figure 1, the fuel cell system 100 has a fuel cell stack (FC stack) 1 and a fuel gas supply and discharge unit 10 that supplies fuel gas to the fuel cell stack 1 and discharges fuel gas from the fuel cell stack 1.

[0010] The fuel cell stack 1 is constructed by stacking multiple power generation cells. Although not shown in the diagram, each power generation cell has a sheet-like or film-like membrane electrode structure formed by integrating a membrane electrode assembly and a film member having a substantially rectangular opening covered by the membrane electrode assembly, an anode separator positioned opposite one side of the membrane electrode structure, and a cathode separator positioned opposite the other side of the membrane electrode structure. The membrane electrode assembly has an electrolyte membrane (e.g., a solid polymer electrolyte membrane), an anode electrode formed on one side of the electrolyte membrane, and a cathode electrode formed on the other side of the electrolyte membrane.

[0011] The anode electrode is formed on one side of the electrolyte membrane and has an electrode catalyst layer that serves as the reaction field for the electrode reaction, and a gas diffusion layer provided in the electrode catalyst layer for diffusing and supplying fuel gas. The cathode electrode is formed on the other side of the electrolyte membrane and has an electrode catalyst layer that serves as the reaction field for the electrode reaction, and a gas diffusion layer provided in the electrode catalyst layer for diffusing and supplying oxidizing gas. An anode channel is formed between the anode electrode and the anode separator, and fuel gas is supplied to the anode channel. A cathode channel is formed between the cathode electrode and the cathode separator, and oxidizing gas is supplied to the cathode channel. A cooling channel is formed between adjacent anode separators, through which a cooling medium flows.

[0012] At the anode electrode, fuel gas (hydrogen) supplied via the anode separator is ionized by the action of a catalyst and moves to the cathode electrode side through the electrolyte membrane. The electrons generated at this time pass through an external circuit and are extracted as electrical energy. At the cathode electrode, oxidizing gas (oxygen) supplied via the cathode separator reacts with hydrogen ions introduced from the anode electrode and electrons that have moved from the anode electrode to produce water. The generated water provides appropriate humidity to the electrolyte membrane, and excess water is discharged to the outside.

[0013] The fuel cell stack 1 is provided with a fuel gas supply port 1a and a fuel gas discharge port 1b. The fuel gas supply and discharge section 10 has a fuel gas supply channel PA11 through which fuel gas flows toward the supply port 1a, and a fuel gas discharge channel PA12 through which fuel gas (fuel exhaust gas) discharged from the discharge port 1b flows. The fuel gas that has flowed through the fuel gas supply channel PA11 is supplied to the anode channel in the fuel cell stack via the supply port 1a. The fuel gas that has flowed through the anode channel is guided to the fuel gas discharge channel PA12 via the discharge port 1b.

[0014] The fuel gas supply channel PA10 includes a tank 11 that stores high-pressure fuel gas, an on-off valve 12 that allows or blocks the flow of fuel gas from the tank 11, an injector (INJ) 13 that injects the fuel gas supplied from the tank 11, and an ejector (EJ) 14 that supplies the fuel gas injected from the injector 13 to the fuel cell stack 1. A pair of pressure sensors 15, each with the same configuration, are connected to the connecting channel PA13 between the ejector 14 and the supply port 1a, and the fuel gas inlet pressure is detected by the pair of pressure sensors 15. One of the pair of pressure sensors 15 is the main sensor, and the other is a redundant sensor provided to improve the reliability of the detection value of the main sensor.

[0015] A gas-liquid separator 16 is connected to the fuel gas exhaust channel PA12. In the gas-liquid separator 16, water contained in the fuel exhaust gas is separated from the fuel exhaust gas and stored. A drain valve 17 is connected to the gas-liquid separator 16. When the drain valve 17 is opened, the water stored in the gas-liquid separator 16 is discharged to the outside. The gas-liquid separator 16 is connected to the ejector 14 via the circulation channel PA14. The fuel exhaust gas separated in the gas-liquid separator 16 is recirculated to the ejector 14 via the circulation channel PA14.

[0016] Figure 2 is a schematic diagram showing the configuration of the ejector 14. As shown in Figure 2, the ejector 14 has a case 140, a nozzle section 141, a suction section 142, a confluence section 143, and a diffuser section 144, each provided within the case 140. The case 140 is connected to an injector 13, a circulation pipe 18 that constitutes the circulation channel PA 14, and a connecting pipe 20 that constitutes the connecting channel PA 13.

[0017] The fuel gas injected from the injector 13 passes through the small-diameter nozzle portion 141 and then flows into the diffuser portion 144 through the confluence portion 143, as shown by the solid-line arrow in FIG. 2. At this time, as shown by the dotted-line arrow in FIG. 2, fuel gas (fuel exhaust gas) is sucked into the ejector 14 from the circulation passage PA14 through the suction portion 142. The sucked fuel gas merges with the fuel gas that has passed through the nozzle portion 141 at the confluence portion 143, and after being made into a uniform flow in the diffuser portion 144, it is led to the connection passage PA13.

[0018] The injector 13 in FIG. 1 may be constituted by a single injector or may be constituted by a plurality of injectors. For example, a small injector with a small injection amount and a large injector with a large injection amount may be provided in parallel. When the injector 13 is constituted by a plurality of injectors, the ejector 14 may be constituted by a plurality of ejectors. For example, a small ejector connected to the small injector and a large ejector connected to the large injector may be provided in parallel within the case 140 (FIG. 2).

[0019] FIG. 3 is a perspective view showing the external shape of the fuel gas supply / discharge unit 10. Hereinafter, for the sake of convenience, as shown in the drawing, the three axial directions orthogonal to each other are defined as the front-rear direction, the left-right direction, and the up-down direction, and the configuration of each part will be described according to this definition. The lower side in the up-down direction corresponds to the gravitational direction. The front in the front-rear direction corresponds to, for example, the front of the vehicle. In FIG. 3, the external shape of the fuel cell stack 1 is shown by a two-dot chain line. As shown in FIG. 3, the fuel cell stack 1 as a whole has a substantially rectangular parallelepiped shape. The fuel gas supply / discharge unit 10 is provided on the left side surface of the fuel cell stack 1.

[0020] More specifically, an ejector 14 is positioned in front of the injector 13, and one end (rear end) of a connecting pipe 20 is connected to the front end of the ejector 14. The connecting pipe 20 extends forward and then to the right, forming a roughly L-shaped connecting channel PA 13 in plan view, and the other end (right end) of the connecting pipe 20 is connected to the left end face of the fuel cell stack 1. A pair of pressure sensors 15 are positioned in front of and above the connecting pipe 20. A gas-liquid separator 16 is positioned below the ejector 14. One end (lower end) of a circulation pipe 18 is connected to the upper end of the gas-liquid separator 16. The other end (upper end) of the circulation pipe 18 bends to the right and is connected to the left side of the case 140 of the ejector 14.

[0021] Figure 4 is an exploded perspective view (viewed from above and diagonally in front) showing the main components of the sensor mounting device 101 according to this embodiment. Figure 4 shows the ejector 14, connecting pipe 20, and circulation pipe 18 as a single unit. Furthermore, Figure 4 shows the pressure sensor 15 separated from the connecting pipe 20.

[0022] As shown by the dotted line in Figure 4, the connecting pipe 20 has a roughly L-shaped connecting channel PA13 that bends from the front to the right at an angle of approximately 90 degrees. The right end of the connecting pipe 20 is provided with a roughly rectangular flange portion 21 that extends in the front-rear and up-down directions. The flange portion 21 is fixed to the left side of the fuel cell stack 1 (Figure 3).

[0023] A flange portion 22 is provided at the top of the connecting pipe 20, in front of the connecting channel PA 13. A flange surface 22a extending in a substantially horizontal direction is provided on the upper surface of the flange portion 22. A substantially circular opening 23 is provided in the center of the flange surface 22a. A spacer member 30 is attached to the flange portion 22, and a pair of pressure sensors 15 are attached to the spacer member 30. The connecting pipe 20 is made of an electrically insulating resin material (insulating material). The spacer member 30 is made of a conductive metal (conductive material).

[0024] Figure 4 shows a virtual horizontal plane PL1 extending in the front-rear, left-right, and right directions along the connecting channel PA13, and a virtual vertical plane PL2 extending in the up-down, left-right, and right directions along the connecting channel PA13. Furthermore, Figure 4 shows a pair of reference lines L1 and L2 extending on the same horizontal plane above the pressure sensor 15. Figure 5 is a perspective view showing the external shape of the sensor mounting device 101 with the pressure sensor 15 attached. As shown in Figure 5, the reference line L1 is a straight line passing through the centers of the pair of pressure sensors 15, and the pair of pressure sensors 15 are positioned on the reference line L1. As shown in Figure 4, the reference line L2 extends in the left-right direction, and the reference line L1 intersects the reference line L2 at a predetermined angle θ of 45 degrees or less. The direction in which the reference line L1 extends is defined as the X1-X2 direction. The reference line L1 passes through the center of the opening 23 of the flange portion 22 of the connecting pipe 20.

[0025] Figure 6 is a cross-sectional view of the main part of the sensor mounting device 101 along the horizontal plane PL1 (a cross-sectional view along the line VI-VI in Figure 4), and Figure 7 is a cross-sectional view of the main part of the sensor mounting device 101 along the vertical plane PL2 (a cross-sectional view along the line VII-VII in Figure 4). Figure 8 is a cross-sectional view of the main part of the sensor mounting device 101 along the vertical plane passing through the reference line L1 (Figure 5). Figures 6 to 8 are cross-sectional views of the state in which the pressure sensor 15 is attached to the connecting pipe 20 via the spacer member 30, and the connecting pipe 20 is attached to the fuel cell stack 1. That is, Figures 6 to 8 are cross-sectional views of the main part of the sensor mounting device 101 in the state in which the fuel gas supply and discharge section 10 is attached to the fuel cell stack 1, as shown in Figure 3.

[0026] As shown in Figure 6, the connecting pipe 20 is provided with a rear end opening 20a on its rear end face and a right end opening 20b on its right end face, forming a connecting flow path PA13 from the rear end opening 20a to the right end opening 20b. A curved section 24 with an arc-shaped inner wall surface is provided at the left front corner of the connecting pipe 20, and the curved section 24 changes the flow direction of the reaction gas that has passed through the ejector 14 (diffuser section 144) from front to the right, as indicated by the arrow. Specifically, the reaction gas collides with the gas collision region AR1 (dotted line) on the inner wall surface of the curved section 24 in front of the rear end opening 20a, causing the flow velocity to decrease and the flow direction to change to the right.

[0027] Let's explain the curved section 24 further. The curved section 24 has a portion where the inner wall surface of the connecting pipe 20 is not straight or flat, but smoothly curved, and by providing the curved section 24, gas flow loss is suppressed. As shown in Figure 6, if L11 is the straight line along the inner wall surface of the ejector 14 on the side in the flow direction of the reaction gas flowing out of the ejector 14, then the center point 25a of the opening 25 is located downstream (to the right) of the straight line L11 in the reaction gas.

[0028] As shown in Figures 6 and 7, an opening 25 is provided at the front end of the connecting pipe 20, above the vertical midpoint of the connecting flow path PA13, along the inner wall surface of the connecting pipe 20, and a hole 26 is provided behind (above) the opening 25. More specifically, a roughly circular or roughly elliptical opening 25 is provided on the front and upper inner wall surface of the connecting pipe 20 (the inner wall surface on the flange portion 22 side in Figure 3). The opening 25 is provided to the right of the gas impact region AR1, that is, downstream in the flow direction of the reaction gas, and offset from the gas impact region AR1. The shape of the opening 25 can be appropriately set according to the shape of the hole 26.

[0029] As shown in Figures 7 and 8, the hole 26 extends forward (or in the X2 direction) and upward from the opening 25. That is, as shown in Figure 8, a wall portion 27 is provided protruding from the opening 25 of the connecting pipe 20, and the wall portion 27 constitutes the hole 26. The wall portion 27 has a support portion 271 that supports the spacer member 30 and an inclined portion 272 below the support portion 271. The support portion 271 is provided at the upper end of the wall portion 27 and has a substantially cylindrical shape centered on the axis L3. The direction in which the axis L3 extends is the direction in which the hole 26 and the spacer member 30 extend, and in Figure 8, the axis L3 extends substantially in the vertical direction. The substantially vertical direction includes the vertical direction along the vertical line and the direction in which the angle from the vertical line is less than or equal to a predetermined angle (for example, 30 degrees or less or 45 degrees or less), i.e., the approximately vertical direction.

[0030] The inclined portion 272 is mainly composed of the lower wall portion 27 and extends from the lower end of the opening 25 to the support portion 271. The inclined portion 272 slopes upward towards the front, thereby gradually increasing the area inside the hole portion 26 (the area of ​​the plane perpendicular to the axis L3) upwards. The upper surface (inclined surface 272a) of the inclined portion 272 is inclined at a predetermined angle θ1 with respect to the horizontal line. The angle that the support portion 271, which is connected to the upper end of the inclined portion 272, makes with respect to the horizontal line is greater than the predetermined angle θ1, and the support portion 271 rises from the upper end of the inclined portion 272.

[0031] The spacer member 30 has a substantially cylindrical case portion 31 having an opening 31a at its lower end, and a pair of holder portions 32 projecting in the X1 and X2 directions from the upper end of the case portion 31. Inside the case portion 31, a cylindrical closed space SP1 is formed with an open lower end and centered on axis L3. The pair of holder portions 32 are configured symmetrically with respect to axis L3. A substantially cylindrical housing space SP2 is formed in the holder portion 32 with an open upper end and centered on axis L4. Axis L4 intersects axis L3 at a predetermined angle α. The larger the predetermined angle α, the larger the area of ​​the upper surface of the central apex 33 of the spacer member 30 above axis CL3 can be formed. The predetermined angle α is set, for example, in the range of 0° < α < 45° so as to form a predetermined upper surface area of ​​the apex 33.

[0032] The lower end of the housing space SP2 intersects with the corner of the upper end of the closed space SP1, and the housing space SP2 and the closed space SP1 communicate with each other. The lower ends of the holder on the X2 direction side and the lower ends on the X1 direction side are bent toward the axis L3. This allows the vertical length of the holder portion 32 to be shortened, and the vertical length of the case portion 31 to be lengthened accordingly. A recess 34 is provided on the outer circumferential surface near the lower end of the case portion 31, and a sealing member 35 such as an O-ring is fitted into the recess 34. A flange portion 36 is provided above the recess 34. As shown in Figures 5 and 7, the flange portion 36 extends in the left-right direction and is fastened to the flange surface 22a of the connecting pipe 20 via bolts 36a.

[0033] As shown in Figure 8, a pair of flange portions 37 are provided at the upper end of the spacer member 30 (holder portion 32) with the axis L3 in between. The upper surface 37a of the flange portion 37 on the X2 side slopes downward with a gentle gradient toward the X2 direction. The upper surface 37a of the flange portion 37 on the X1 side slopes downward with a gentle gradient toward the X1 direction. Therefore, the upper surface 37a of the flange portion 37 on the X2 side and the upper surface 37a of the flange portion 37 on the X1 side are not on the same plane, and the pair of extended surfaces obtained by extending these upper surfaces 37a, 37a intersect on the axis L3.

[0034] As shown in Figures 5 and 8, a pair of pressure sensors 15 are attached to a pair of flange portions 37. Each pressure sensor 15 has a sensor body 151 and a flange portion 152 that protrudes outward from the sensor body 151 (on the opposite side of the axis L3). Through holes are provided in the flange portion 152, and bolts 38 inserted through the through holes are screwed into threaded holes provided in the flange portion 37 of the spacer member 30, thereby fastening the pressure sensor 15 to the spacer member 30.

[0035] As shown in Figure 8, the sensor body 151 has a roughly cylindrical metal body portion 151a, which is fitted into the housing space SP2. A detection unit for detecting the pressure of the reaction gas is provided at the tip (lower end) of the body portion 151a. When the body portion 151a is fitted, the lower end of the sensor body 151 is located above the intersection of the closed space SP1 and the housing space SP2. A bottomed screw hole 33a is provided on the upper surface of the top portion 33 along the axis L3.

[0036] As shown in Figure 5, a bolt 42 is screwed into the screw hole 33a with the tip 41 of the ground wire 40 sandwiched in between, thereby fixing the ground wire 40 between the pair of pressure sensors 15. Although not shown in the figure, the end of the ground wire 40 is connected to the vehicle body, and the spacer member 30 is grounded via the ground wire 40. This allows static electricity at the tip of the pressure sensor 15 to be discharged to the ground via the spacer member 30 and the ground wire 40. As a result, static electricity buildup on the pressure sensor 15 can be suppressed, and abnormal output of the pressure sensor 15 can be prevented. A connection part 153 is provided at the upper end of the pressure sensor 15, facing rearward or to the left, and electrical wires 43 such as power lines and signal lines are connected to the connection part 153.

[0037] The main operation of the sensor mounting device 101 according to this embodiment will now be described. When the fuel cell is operating, fuel gas is supplied to the fuel cell stack 1 via the fuel gas supply and discharge section 10. The fuel gas flows through a substantially L-shaped connecting channel PA13 inside the connecting pipe 20, along the arrow in Figure 6. An opening 25 is provided in the inner wall of the connecting pipe 20 along the connecting channel PA13, and a metal spacer member 30 is attached to a hole 26 at the back of the opening 25. The spacer member 30 has a substantially cylindrical closed space SP1, and the pressure sensor 15 is housed in a housing space SP2 above the closed space SP1. Therefore, the detection part at the tip of the pressure sensor 15 is not exposed to the gas channel (connecting channel PA13). Thus, it is possible to suppress direct contact between the fuel gas in the connecting channel containing water vapor and the detection part of the pressure sensor 15, and the pressure of the fuel gas can be accurately detected by the pressure sensor 15.

[0038] In particular, the fuel gas flowing from the diffuser section 144 into the connecting pipe 20 collides with the gas collision region AR1 (Figure 6), but the opening 25 of the hole section 26 is located downstream of the collision region. This prevents the fuel gas from flowing forcefully into the closed space SP1, and the pressure sensor 15 detects the pressure of the fuel gas with reduced flow velocity. This improves the accuracy of the fuel gas pressure detection by the pressure sensor 15. Since the closed space SP1 has a roughly cylindrical shape, a good swirling flow of fuel gas can be generated inside the spacer member 30. That is, a swirling flow can be generated that flows in through the opening 31a and flows out through the opening 31a, or more specifically, a swirling flow that is drawn into the gas flow of the connecting channel PA13. This prevents irregular flow from occurring within the closed space SP1, and allows for accurate detection of the fuel gas pressure.

[0039] In this embodiment, a pair of pressure sensors 15 are provided symmetrically with respect to the axis L3. The pair of pressure sensors 15 are respectively placed in a pair of containment spaces SP2 above the closed space SP1. As described above, a good swirling flow of fuel gas is generated in the closed space SP1, so that fuel gas with the same flow velocity flows into the pair of containment spaces SP2. As a result, the pair of pressure sensors 15 can detect the pressure of fuel gas under the same conditions, and differences in the detected values ​​of the pair of pressure sensors 15 can be suppressed.

[0040] An earth wire 40 is connected to the top 33 of the spacer member 30 at a position on the axis L3. This allows static electricity accumulated at the tip of the pressure sensor 15 to be discharged to the ground, preventing abnormal output of the pressure sensor 15. Furthermore, since the earth wire 40 is positioned midway between the pair of pressure sensors 15, a single earth wire 40 can provide equivalent grounding effects to both the pair of pressure sensors 15.

[0041] The opening 26 of the connecting pipe 20 is formed by a wall 27, which has an inclined surface 272a that slopes upward from the opening 25 at a predetermined angle θ1, and a spacer member 30 is positioned above the inclined surface 272a. This prevents generated water or condensed water in the connecting channel PA13 from entering the closed space SP1 and causing the pressure sensor 15 to be submerged in water when the vehicle is stopped in an inclined position, thereby improving the detection accuracy of the pressure sensor 15. Furthermore, the wall 27 has a support portion 271 that is connected to the inclined portion 272 and rises upward at an obtuse angle relative to the inclined portion 272. This makes it easier to generate a swirling flow of fuel gas in the closed space SP1, allowing the pressure sensor 15 to detect the fuel gas pressure accurately.

[0042] This embodiment can provide the following effects and advantages. (1) The sensor mounting device 101 comprises a connecting pipe 20 made of insulating material that forms a fuel gas supply channel PA11 (connecting channel PA13) through which reaction gas (fuel gas) for the fuel cell flows, a spacer member 30 made of conductive material that is mounted in a hole 26 provided in the connecting pipe 20, a pressure sensor 15 attached to the spacer member 30, and a ground wire 40 attached to the spacer member 30 (Figures 5-8). The spacer member 30 has a case portion 31 provided with an opening 31a located in the hole 26, and a flange portion 36 provided with a holder portion 32 to which the pressure sensor 15 is attached, and is configured to extend substantially upward from the lower end of the case portion 31 to the flange portion 36, forming a closed space SP1 that communicates with the connecting channel PA13 through the opening 31a (Figure 8).

[0043] As a result, the pressure sensor 15 is positioned away from the connecting channel PA13 via the closed space SP1. Therefore, the detection part at the tip of the pressure sensor 15 is not exposed to the gas channel (connecting channel PA13), which prevents fuel gas containing water vapor from directly contacting the detection part of the pressure sensor 15. Consequently, the pressure sensor 15 can accurately detect the pressure of the fuel gas.

[0044] (2) The hole 26 is composed of a wall 27 (Figure 8). The wall 27 extends from the opening 25 facing the connecting channel PA13 to the opening 31a of the spacer member 30 (Figure 8). The wall 27 has an inclined surface 272a that slopes upward from the opening 25 to the opening 31a (Figure 8). This prevents generated water or condensed water in the connecting channel PA13 from entering the closed space SP1 and causing the pressure sensor 15 to be submerged in water when the vehicle is stopped in an inclined position, and improves the detection accuracy of the pressure sensor 15.

[0045] (3) The hole 26 is composed of a wall 27 (Figure 8). The wall 27 extends from the opening 25 facing the connecting channel PA13 to the opening 31a of the spacer member 30 (Figure 8). The wall 27 has an inclined portion 272 extending from the opening 25 and a support portion 271 that is connected to the inclined portion 272, rises higher than the inclined portion 272, and extends to the opening 31a (Figure 8). The inclined portion 272 and the support portion 271 intersect at an obtuse angle (Figure 8). This makes it easier to generate a swirling flow of fuel gas in the closed space SP1, and the pressure sensor 15 can accurately detect the pressure of the fuel gas.

[0046] (4) The connecting pipe 20 has a curved section 24 that curves the connecting flow path PA 13 (Figure 6). The opening 25 of the hole 26 facing the connecting flow path PA 13 is provided downstream of the curved section 24 (Figure 6). As a result, the pressure sensor 15 detects the pressure of the fuel gas whose flow velocity has decreased after colliding with the inner wall surface of the connecting pipe 20, thereby improving the accuracy of the fuel gas pressure detection by the pressure sensor 15.

[0047] (5) A pair of holder portions 32 are provided on the upper part of the spacer member 30 to form a housing space SP2 for the pressure sensor 15 (Figure 8). The ground wire 40 is placed between the pair of holder portions 32 (Figures 5, 8). This allows the pair of pressure sensors 15 to obtain the same grounding effect from each other with a single ground wire 40.

[0048] (6) The sensor mounting device 101 is applied to the pressure sensor 15 that detects the pressure of the fuel gas. This allows for accurate detection of the pressure of the fuel gas containing water vapor.

[0049] (7) The spacer member 30 is configured to form a closed space with a substantially cylindrical shape (Figure 8). This allows for good generation of swirling flow inside the spacer member 30, thereby improving the accuracy of pressure detection by the pressure sensor 15.

[0050] The above embodiment can be modified into various forms. Several modifications are described below. In the above embodiment, the sensor mounting device 101 was applied to the connecting pipe 20 between the ejector 14 and the fuel cell stack 1. However, the sensor mounting device of the present invention can be applied to other flow path forming members made of insulating material, as well as to gas flow paths through which reaction gas for the fuel cell flows. That is, it can be applied to other flow path forming members that constitute a flow path through which fuel gas flows, and it can also be applied to flow path forming members that constitute a flow path for oxidizer gas.

[0051] In the above embodiment, the pressure sensor 15 is attached to the spacer member 30, but other sensors (e.g., temperature sensors) may also be attached to the spacer member, and the sensors to which the sensor mounting device is applied are not limited to those described above. In the above embodiment, the ground wire 40 is connected to the top portion 33 of the spacer member 30 between the pair of holder portions 32 (sensor mounting portions), but the attachment position of the ground wire is not limited to those described above, as long as it is attached to a spacer member made of a conductive material. In the above embodiment, a pair of pressure sensors 15 are attached to the spacer member 30 via a pair of holder portions 32, but the number of sensors attached to the spacer member may be one or three or more. Therefore, the number of holder portions 32 is not limited to those described above.

[0052] In the above embodiment, the hole 26 (connection hole) of the connecting pipe 20 is formed by a wall portion 27 extending from the opening 25 facing the connecting flow path PA 13 to the opening 31a (communication hole) of the spacer member 30. More specifically, the wall portion 27 has an inclined surface 272a that slopes upward from the opening 25 to the opening 31a. The wall portion 27 also has an inclined portion 272 (first wall portion) extending from the opening 25 and a support portion 271 (second wall portion) that is connected to the inclined portion 272, rises higher than the inclined portion 272, and extends to the opening 31a, with the inclined portion 272 and the support portion 271 intersecting at an obtuse angle. However, the configuration of the wall portion of the flow path forming member can be anything as long as it is provided from the opening facing the gas flow path to the communication hole (lower end opening) of the spacer member.

[0053] In the above embodiment, the case portion 31 of the spacer member 30 is configured to form a substantially cylindrical closed space SP1, but the shape of the closed space formed by the spacer member is not limited to that described above. In the above embodiment, the spacer member 30 is configured to have a substantially cylindrical case portion 31 and a pair of holder portions 32, but the configuration of the spacer member, which is mounted in a hole (connection hole) provided in the flow path forming member and is made of a conductive material, is not limited to that described above. That is, the configuration of the spacer member can be anything as long as it has one end provided with a communication port (e.g., opening 31a) located in the connection hole and the other end provided with a sensor mounting portion (e.g., holder portion 32) to which a sensor (e.g., pressure sensor 15) is attached, and extends from one end to the other in a predetermined direction intersecting the flow direction of the reaction gas, forming a closed space that communicates with the gas flow path. Therefore, the predetermined direction intersecting the flow direction of the reaction gas is not limited to upward or substantially upward. In this context, "intersection" refers to both two or more linear lines meeting at a single point, and lines not meeting at a single point but intersecting in a certain region (i.e., being in a skew relationship).

[0054] In the above embodiment, an example of applying the fuel cell system 100 to a vehicle was described, but the fuel cell system to which the sensor mounting device of the present invention is applied can also be applied to mobile bodies other than vehicles such as aircraft and ships, robots, and various industrial machines.

[0055] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other.

[0056] 15 Pressure sensor, 20 Connecting pipe, 24 Curved section, 25 Opening, 26 Hole section, 27 Wall section, 30 Spacer member, 31 Case section, 31a Opening, 32 Holder section, 40 Ground wire, 100 Fuel cell system, 101 Sensor mounting device, 271 Support section, 272 Inclined section, 272a Inclined surface, PA13 Connecting channel, SP1 Closed space, SP2 Housing space

Claims

1. A flow path forming member made of insulating material, which forms a gas flow path through which the reaction gas for the fuel cell flows, A spacer member made of a conductive material is attached to a connection hole provided in the aforementioned flow path forming member, A sensor attached to the spacer member, The spacer member is equipped with an earth wire attached to the spacer member, The spacer member has one end provided with a communication port located in the connection hole, and the other end provided with a sensor mounting portion to which the sensor is attached, and extends from the one end to the other end in a predetermined direction intersecting the flow direction of the reaction gas, and is configured to form a closed space that communicates with the gas flow path through the communication port. The other end of the spacer member has a pair of sensor mounting portions, The sensor mounting device is characterized in that the ground wire is positioned between the pair of sensor mounting portions.

2. In the sensor mounting device according to claim 1, The connection hole portion has a wall portion that extends from the opening facing the gas flow path to the communication opening of the spacer member, The sensor mounting device is characterized in that the wall portion has an inclined surface that slopes upward from the opening toward the communication port.

3. In the sensor mounting device according to claim 1, The connection hole portion has a wall portion that extends from the opening facing the gas flow path to the communication opening of the spacer member, The wall portion comprises a first wall portion extending from the opening, and a second wall portion connected to the first wall portion, rising higher than the first wall portion and extending toward the communication opening. A sensor mounting device characterized in that the first wall portion and the second wall portion intersect at an obtuse angle.

4. In the sensor mounting device according to claim 1, The flow path forming member has a curved portion that curves the gas flow path, A sensor mounting device characterized in that the opening of the connection hole facing the gas flow path is provided downstream of the curved portion.

5. In the sensor mounting device according to Claim 1, The sensor mounting device is characterized in that the sensor is a pressure sensor that detects the pressure of the reaction gas.

6. In the sensor mounting device according to any one of claims 1 to 5, The sensor mounting device is characterized in that the spacer member is configured to form the closed space which is substantially cylindrical in shape.

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