Gas detector

Abstract

To increase the response speed of a gas sensor.SOLUTION: The gas detector includes: a housing with a first opening; a housing portion disposed inside the housing and having a second opening at a position overlapping the first opening; a gas sensor disposed inside the housing portion, for detecting a predetermined gas; and a filter covering the second opening, for allowing the predetermined gas to pass therethrough. An end portion of the filter is fixed by an insert portion provided around the second opening of the housing portion. The inner wall of the housing portion is located inside the end portion of the filter fixed by the insert portion when viewed from above.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a gas detection device. [Background technology]

[0002] Vehicles powered by fuel cells are equipped with a gas detection device for detecting, for example, hydrogen gas leaks. For example, Patent Document 1 discloses that a gas sensor is surrounded by a partition wall. This allows the air around the gas sensor to be quickly replaced, improving the response speed of the gas sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-027499 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, the inner shape of the cavity surrounded by the partition wall is configured to be larger than the area of ​​the filter for replacing the atmosphere inside the cavity, which makes it impossible to sufficiently increase the response speed of the gas sensor.

[0005] The present invention has been made in view of the above, and an object of the present invention is to provide a gas detection device that can increase the response speed of a gas sensor. [Means for solving the problem]

[0006] The gas detection device of the embodiment comprises a housing having a first opening, a storage unit installed in the housing and having a second opening at a position overlapping the first opening, a gas sensor installed in the storage unit and capable of detecting a predetermined gas, and a filter covering the second opening and allowing the predetermined gas to pass through, wherein an end of the filter is fixed by an insert portion that the storage unit has around the second opening, and the inner wall of the storage unit is located inside the end of the filter fixed by the insert portion when viewed from above.

[0007] The gas detection device according to the embodiment can increase the response speed of the gas sensor. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a gas detection device according to an embodiment. [Figure 2] FIG. 2 is a perspective view showing an example of the configuration of the gas detection device according to the embodiment. [Figure 3] FIG. 3 is a top view including a container provided in the gas detection device according to the embodiment. [Figure 4] FIG. 4 is a top view including a container provided in the gas detection device according to the embodiment. [Figure 5] FIG. 5 is a cross-sectional view including a housing portion provided in the gas detection device according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view including a housing portion provided in a gas detection device according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions, results, and advantages brought about by the configurations, are merely examples. The present invention can be realized using configurations other than those disclosed in the following embodiments, and it is possible to obtain at least one of the various advantages and derivative advantages based on the basic configurations.

[0010] (Example of gas detection device configuration) 1 and 2 are perspective views showing an example of the configuration of gas detection device 1 according to an embodiment. More specifically, Fig. 1 is a perspective view of the upper side of gas detection device 1, showing a part of housing 10 exploded. Fig. 2 is a perspective view of the lower side of gas detection device 1.

[0011] The gas detection device 1 of the embodiment is mounted on a vehicle or the like powered by a fuel cell, for example, and is configured to be able to detect hydrogen gas.

[0012] As shown in FIGS. 1 and 2, gas detection device 1 includes housing 10, housing portion 20, gas sensor 30, printed circuit board (PCB) 40, and filter 50.

[0013] The housing 10 is made of resin and includes a top cover 11 and a case 12. The case 12 is configured in a box shape that can store therein an accommodating section 20, a gas sensor 30, a printed circuit board 40, a filter 50, etc. The top cover 11 is configured to be attachable to the top surface of the case 12 so as to close the inside of the case 12.

[0014] Mounting sections 12s are provided on both side surfaces of case 12, allowing gas detection device 1 to be mounted at a predetermined position on the vehicle using mounting fixtures such as screws. Opening section 14 is provided on the back surface of case 12. Opening section 14 is configured to allow outside air to be taken in from gas detection device 1.

[0015] Case 12 houses a printed circuit board 40 that is installed throughout the entire interior of case 12 so as to separate the interior of case 12 into upper and lower sections. Printed circuit board 40 controls gas sensor 30 and the like, acquires detection results of hydrogen gas and the like from gas sensor 30, and outputs the results to a device external to gas detection device 1. The external device to gas detection device 1 is, for example, an electronic control unit (ECU) that monitors for hydrogen gas leaks.

[0016] The accommodation unit 20 is attached to, for example, a printed circuit board 40 and is accommodated in a lower space within the case 12 separated by the printed circuit board 40. That is, the accommodation unit 20 is disposed in the space between the printed circuit board 40 and the bottom surface of the case 12. The accommodation unit 20 has, for example, a circular outer shape and is made of resin so that the gas sensor 30 and the like can be accommodated therein. The accommodation unit 20 also has an opening 24 at a position that overlaps in the vertical direction with the opening 14 provided on the back surface of the case 12. A filter 50 is fitted into the opening 24 of the accommodation unit 20.

[0017] The opening 14 of the housing 10 is an example of a first opening, and the opening 24 of the housing 20 is an example of a second opening.

[0018] The filter 50 is made of a resin such as polytetrafluoroethylene (PTFE) and is configured to block water droplets and the like from outside the housing 10 and allow outside air to communicate between the inside and outside of the housing 10.

[0019] The gas sensor 30 is configured to detect the hydrogen gas concentration using, for example, a thermal conductivity detection (TCD) method. The TCD method utilizes differences in thermal conductivity depending on the gas species, and detects changes in the temperature of the filament due to differences in the thermal conductivity of the hydrogen gas being detected as changes in electrical resistance. This makes it possible to identify the hydrogen gas concentration in the atmosphere surrounding the gas sensor 30. For this reason, the gas sensor 30 includes an integrated circuit (IC) chip equipped with a TCD-type hydrogen gas detection mechanism and an IC chip for measuring temperature and humidity, which affect the thermal conductivity of hydrogen gas, etc.

[0020] With the above configuration, one or more gas detection devices 1 of the embodiment are installed in locations where hydrogen gas leakage may occur, such as near a fuel tank in a vehicle or near a hydrogen gas flow path inside the vehicle.

[0021] Global Technical Regulation No. 13 (GTR13), an international standard for hydrogen and fuel cell vehicles, stipulates that in the event of a hydrogen gas leak, a warning must be issued if the hydrogen gas concentration reaches 2 vol% or higher, and the main stop valve of the fuel tank must be closed if the hydrogen gas concentration reaches 3 vol% or higher. The ECU that monitors hydrogen gas leaks performs control that satisfies the provisions of GTR13 based on the detection results from gas detection device 1.

[0022] (Example of storage unit configuration) Next, a detailed configuration example of accommodating section 20 included in gas detection device 1 of the embodiment will be described with reference to Figures 3 and 4. Figures 3 and 4 are top views including accommodating section 20 included in gas detection device 1 according to the embodiment.

[0023] In order to quickly detect and respond to hydrogen gas leakage, gas detection device 1 of the embodiment is devised to improve response speed, as will be described below.

[0024] 3 and as described above, the housing 20 has, for example, a circular outer shape and has an internal space 22 capable of housing the gas sensor 30. The internal space 22 of the housing 20 is surrounded by an inner wall 21 of the housing 20 that is provided to fit along the outer shape of the gas sensor 30. An opening 24, for example, having a circular shape, is provided in the center of the bottom surface of the housing 20 so as to overlap vertically with the opening 14 of the housing 10 described above. A filter 50 is fitted into the opening 24 of the housing 20.

[0025] As described above, the gas sensor 30 is provided in the internal space 22 of the housing 20. The gas sensor 30 has an IC chip 31 for detecting hydrogen gas and an IC chip 33 for measuring temperature and humidity. These IC chips 31, 33 have, for example, a rectangular shape when viewed from above, and leads 32 extending outward from the IC chip 31 for detecting hydrogen gas protrude from two opposing end sides.

[0026] When viewed from above, the rectangular main body of IC chip 31, excluding leads 32, is disposed inside the outer edge of opening 24 of housing portion 20, into which filter 50 is fitted. This arrangement enables IC chip 31 to detect with high accuracy hydrogen gas in the outside air introduced into housing portion 20 via filter 50.

[0027] The IC chip 33 is disposed adjacent to the IC chip 31 at a position partially removed from the opening 24 of the housing section 20. This allows the IC chip 33 to detect the temperature and humidity around the IC chip 31 with high accuracy.

[0028] 4, the inner wall 21 of the housing 20 is indicated by a thick line, and other components are indicated by dashed lines. As shown in FIG. 4 and as described above, the inner wall 21 of the housing 20 is provided so as to follow the outer shape of the gas sensor 30, without following the circular outer shape of the housing 20.

[0029] More specifically, inner wall 21 of accommodating section 20 is disposed in the center of opening 24, and has two protruding portions 211 that protrude toward the corners of IC chip 31 at portions facing two of the four corners of rectangular IC chip 31 adjacent to IC chip 33. Furthermore, inner wall 21 of accommodating section 20 has one protruding portion 211 that protrudes toward one of the four edges of rectangular IC chip 31, facing the edge opposite IC chip 33. Furthermore, inner wall 21 of accommodating section 20 has three recessed portions 212 that are recessed from the remaining three edges of rectangular IC chip 31, i.e., the two edges from which leads 32 protrude and the edge adjacent to IC chip 33. As a result, inner wall 21 of accommodating section 20 has a generally T-shaped outline when viewed from above.

[0030] Of the three recessed portions 212 that inner wall 21 of accommodating portion 20 has, two recessed portions 212 that face each other with IC chip 31 in between, and the protruding portion 211 adjacent to these recessed portions 212, in the space surrounded by these recessed portions 212. In the space surrounded by the remaining recessed portion 212 of the three recessed portions 212 and the protruding portion 211 adjacent to it, IC chip 33 adjacent to IC chip 31 is disposed.

[0031] In this way, by providing the inner wall 21 of the housing 20 close to the outer shape of the gas sensor 30, the volume of the internal space 22 of the housing 20 can be reduced, and replacement of the atmosphere in the internal space 22 can be promoted. As a result, in the event of a hydrogen gas leak, for example, the gas sensor 30 can successively detect changes in the gradually increasing hydrogen gas concentration, improving the response speed of the gas sensor 30.

[0032] At this time, it is preferable that the distance between the gas sensor 30 and the inner wall 21 of the accommodating section 20 at a portion closer to the gas sensor 30, such as a protruding portion 211 that protrudes toward the IC chip 31, is determined taking into consideration the assembly tolerance of the gas sensor 30 within the accommodating section 20. In other words, it is preferable that the inner wall 21 of the accommodating section 20 and the gas sensor 30 are close to each other while maintaining a distance that allows the gas sensor 30 to be assembled within the accommodating section 20.

[0033] The accommodating section 20 having the above-described configuration is integrally molded, including the inner wall 21 having a complex shape, by, for example, injection molding using a mold. More specifically, the accommodating section 20 having the above-described shape is formed by, for example, injecting a resin material into a mold in which the filter 50 is placed.

[0034] In this way, by integrally molding the accommodating section 20, including the inner wall 21 with a complex shape, it is possible to eliminate complicated processes such as filling the internal space 22 of the accommodating section 20 with material to match the external shape of the gas sensor 30, and it is possible to inexpensively manufacture a gas detection device 1 including a accommodating section 20 with a reduced internal space 22.

[0035] (Comparative Example) Next, the detailed configuration of accommodating section 20 included in gas detection device 1 of the embodiment will be further described in comparison with a gas detection device of a comparative example using Figures 5 and 6. Figure 5 is a cross-sectional view including accommodating section 20 included in gas detection device 1 of the embodiment. Figure 6 is a cross-sectional view including accommodating section 20x included in a gas detection device of the comparative example.

[0036] As shown in Figures 5 and 6, gas detection device 1 of the embodiment and the gas detection device of the comparative example are attached to printed circuit board 40 via O-ring 23 and include accommodating portions 20, 20x each having openings 24, 24x on the lower surface, filter 50 whose end is fixed by insert portions 241, 241x provided at the lower end of accommodating portions 20, 20x and covers each opening 24, 24x, and gas sensor 30 accommodated in internal spaces 22, 22x of accommodating portions 20, 20x.

[0037] As described above, the housing portions 20, 20x are airtightly attached to the printed circuit board 40 via the O-ring 23. Therefore, the atmosphere inside the housing portions 20, 20x is exchanged solely via the filter 50 on the underside of the housing portions 20, 20x. Furthermore, the insert portions 241, 241x that secure the ends of the filter 50 are formed by injection molding the housing portions 20, 20x with the filter 50 inserted into a mold, as described above. Fixing the filter 50 around the openings 24, 24x of the housing portions 20, 20x using this method is also referred to as insert molding of the filter 50.

[0038] 6, the internal space 22x provided in the housing portion 20x of the comparative example is provided with a relatively large margin compared to the size of the gas sensor 30. In other words, the inner wall 21x surrounding the internal space 22x of the housing portion 20x of the comparative example is disposed at a position away from the gas sensor 30, for example, at a distance exceeding the assembly tolerance of the gas sensor 30 to the housing portion 20x.

[0039] For this reason, the inner wall 21x of the accommodating portion 20x of the comparative example has an outer shape, when viewed in the horizontal direction, larger than the outer shape of the entire filter 50. In other words, when viewed from above, the inner wall 21x of the accommodating portion 20x of the comparative example is located outward from the end of the filter 50 fixed by the insert portion 241x at the lower end of the accommodating portion 20x.

[0040] 5, the internal space 22 provided in the housing portion 20 of the embodiment is provided as close as possible to the gas sensor 30, as described above. In other words, in the inner wall 21 surrounding the internal space 22 of the housing portion 20 of the embodiment, the distance from the gas sensor 30 is, for example, equal to or less than the assembly tolerance of the gas sensor 30 to the housing portion 20, as described above.

[0041] For this reason, the inner wall 21 of the accommodating portion 20 of the embodiment has an outer shape, when viewed in the horizontal direction, that is smaller than the outer shape of the entire filter 50. In other words, when viewed from above, the inner wall 21 of the accommodating portion 20 of the embodiment is located more inward than the end of the filter 50 that is fixed by the insert portion 241 at the lower end of the accommodating portion 20.

[0042] (Overview) In fuel cell vehicles and the like that use hydrogen gas as fuel, a gas detection device for detecting, for example, hydrogen gas leaks is installed. In order to immediately detect and respond to hydrogen gas leaks, the gas detection device is required to be quick to respond.

[0043] According to gas detection device 1 of the embodiment, inner wall 21 of housing 20, when viewed from above, is located inside the end of filter 50 fixed by insert 241 around opening 24. This reduces internal space 22 of housing 20, promoting the exchange of the atmosphere within internal space 22 and enabling the response speed of gas sensor 30 to be increased.

[0044] According to the gas detection device 1 of the embodiment, on the inner wall 21 of the housing 20, protruding portions 211 that face some corners and some edge sides of the IC chip 31, which is the main body of the gas sensor 30, protrude toward the IC chip 31. This makes it possible to further reduce the internal space 22 of the housing 20 and further increase the response speed of the gas sensor 30.

[0045] According to gas detection device 1 of the embodiment, protruding portion 211 of inner wall 21 of accommodating portion 20 protrudes to a position overlapping the outer edge of opening 24 when viewed from above. This makes it possible to reduce internal space 22 of accommodating portion 20 while avoiding interference with the exchange of the atmosphere inside accommodating portion 20 via filter 50, and to increase the response speed of gas sensor 30.

[0046] According to the gas detection device 1 of the embodiment, the IC chip 31 of the gas sensor 30 has leads 32 extending toward the recessed portion 212 of the inner wall 21 of the accommodating portion 20, on at least a part of the edge facing the recessed portion 212. By thus forming the inner wall 21 of the accommodating portion 20 in a shape that follows the outer shape of the gas sensor 30, the internal space 22 of the accommodating portion 20 can be reduced as much as possible, and the response speed of the gas sensor 30 can be increased.

[0047] Although the embodiments of the present invention have been described above, the above embodiments are presented as examples and are not intended to limit the scope of the invention. This novel embodiment can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. This embodiment and its modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as set forth in the claims. [Explanation of symbols]

[0048] 1...gas detection device, 10...housing, 14, 24...opening, 20...accommodation section, 21...inner wall, 22...internal space, 30...gas sensor, 31, 33...IC chip, 32...lead, 40...printed circuit board, 50...filter, 211...protruding section, 212...retracting section, 241...insertion section.

Claims

1. a housing provided with a first opening; a housing portion disposed within the housing and having a second opening portion overlapping the first opening portion; a gas sensor installed in the container and capable of detecting a predetermined gas; a filter that covers the second opening and allows the predetermined gas to pass through; The end of the filter is The housing portion is fixed by an insert portion provided around the second opening, The inner wall of the storage section is When viewed from above, the filter is located inside the end of the filter fixed by the insert portion. Gas detection equipment.

2. The second opening is It has a circular shape when viewed from above, The main body of the gas sensor comprises: The outer shape of the second opening has corners and edges when viewed from above, and is positioned inside the outer edge of the second opening, On the inner wall of the storage portion, a portion of the main body portion facing the corner or the end edge protrudes toward the main body portion; 2. The gas detection device according to claim 1.

3. On the inner wall of the storage portion, The portion protruding toward the main body portion protrudes to a position overlapping an outer edge of the second opening portion when viewed from above.

3. The gas detection device according to claim 2.

4. The main body of the gas sensor comprises: The outer shape has a plurality of end sides when viewed from above, On the inner wall of the storage portion, a portion of the body portion of the gas sensor that faces one of the plurality of end sides is recessed from the body portion, The gas sensor comprises: The inner wall has a lead extending toward the recessed inner wall of the accommodating portion at the one end side facing the recessed portion from the main body portion.

3. The gas detection device according to claim 2.

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