Gas sensor

Abstract

This application discloses a gas sensor, including a detection housing assembly and a detection component connected together. The detection housing assembly has a detection chamber, and the detection component includes a light source and a photodetector. The light source and the photodetector are at least partially located within the detection chamber. The detection housing assembly includes a first detection housing, which includes a first reflective surface. Light emitted from the light source can be reflected to the photodetector at least through the first reflective surface. The gas sensor is defined to have a height direction. On a projection plane perpendicular to the height direction, the projection of the first reflective surface is a U-shaped surface. In this application, the projection of the first reflective surface is a U-shaped surface. Compared to the projection of the first reflective surface as a U-shaped line segment, the reflective area of ​​the first reflective surface is larger, thereby improving the reflective effect of the first reflective surface.

Description

Technical Field

[0001] This application relates to the field of sensor technology, and more particularly to a gas sensor for vehicles. Background Technology

[0002] In related technologies, a gas sensor includes a detection housing assembly and a detection component, which are connected. The detection housing assembly has a detection chamber, and the detection component includes a light source and a photodetector. The light source is at least partially located in the detection chamber, and the photodetector is at least partially located in the detection chamber.

[0003] The detection housing assembly includes a first detection housing, which includes a first reflective surface. Light emitted by the light source can be reflected to the photodetector through the first reflective surface. On the projection surface perpendicular to the height direction of the gas sensor, the projection of the first reflective surface is a U-shaped line segment. The reflective area of ​​the first reflective surface is small, and the reflection effect of the first reflective surface is poor. Summary of the Invention

[0004] In view of the above-mentioned problems existing in related technologies, this application provides a gas sensor aimed at improving the reflection effect of the first reflecting surface.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A gas sensor includes a detection housing assembly and a detection component connected to each other. The detection housing assembly has a detection chamber, and the detection component includes a light source and a photodetector. The light source is at least partially located in the detection chamber, and the photodetector is at least partially located in the detection chamber.

[0007] The detection housing assembly includes a first detection housing, the first detection housing includes a first reflective surface, and the light emitted by the light source can be reflected to the photodetector at least through the first reflective surface;

[0008] The gas sensor is defined to have a height direction, and on a projection plane perpendicular to the height direction, the projection of the first reflective surface is a U-shaped surface.

[0009] In this application, the light emitted by the light source can be reflected to the photodetector through the first reflective surface. On the projection surface perpendicular to the height direction of the gas sensor, the projection of the first reflective surface is a U-shaped surface. Compared with the projection of the first reflective surface as a U-shaped line segment, the reflection area of ​​the first reflective surface is relatively large, thereby improving the reflection effect of the first reflective surface. Attached Figure Description

[0010] Figure 1 This is a three-dimensional structural schematic diagram of the gas sensor of this application;

[0011] Figure 2 yes Figure 1 The diagram shows an explosion of a gas sensor.

[0012] Figure 3 yes Figure 1 A schematic diagram of an explosion from another angle, showing the gas sensor;

[0013] Figure 4 yes Figure 1 A schematic cross-sectional view of the gas sensor shown.

[0014] Figure 5 yes Figure 1 A cross-sectional schematic diagram of the gas sensor shown;

[0015] Figure 6 yes Figure 1 A schematic diagram of the planar structure of the first detection housing in the gas sensor shown;

[0016] Figure 7 yes Figure 1 A three-dimensional structural diagram of the first detection housing in the gas sensor shown;

[0017] Figure 8 yes Figure 1 The diagram shows a planar structure of the first housing of the gas sensor.

[0018] In the figure, 10 is the detection housing assembly; 101 is the detection chamber; 11 is the first detection housing; 111 is the first reflective surface; 1111 is the sub-reflective surface; 112 is the second reflective surface; 113 is the third reflective surface; 114 is the fourth reflective surface; 115 is the fifth reflective surface; 116 is the sixth reflective surface; 117 is the top surface; 1171 is the limiting groove; 1172 is the first vent hole; 118 is the vent opening; 12 is the second detection housing; 121 is the first through hole; 122 is the first notch; 20 is the detection assembly; 21 is the light source; 22 is the photodetector; 23 is the circuit board; 30 is the outer shell assembly; 301 is the mounting cavity; 31 is the first outer shell; 311 is the second vent hole; 312 is the third vent hole; 32 is the second outer shell; 40 is the waterproof and breathable membrane; L is the length direction of the gas sensor; W is the width direction of the gas sensor; H is the height direction of the gas sensor. Detailed Implementation

[0019] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0020] In recent years, people have paid increasing attention to air quality. Carbon dioxide is one of the important indicators for air quality monitoring. In the fields of heating, ventilation and air conditioning, gas sensors are used to monitor the carbon dioxide content in indoor or vehicle rooms. When the carbon dioxide content exceeds the set limit, fresh air is introduced through the ventilation system in the heating, ventilation and air conditioning system, which can effectively improve energy utilization efficiency and is of great significance for energy conservation and environmental protection.

[0021] Carbon dioxide, a key component of the novel refrigerant R744, is an ideal refrigerant for future air conditioning technology due to its minimal ozone layer depletion potential (ODP value of zero and GWP value of very low). However, in practical applications, R744 refrigerant leaks directly impact cooling efficiency and could potentially lead to safety hazards such as asphyxiation. Therefore, gas sensors are essential for monitoring refrigerant leaks. This presents a significant market opportunity for R744 refrigerant leak detection using gas sensors. For monitoring R744 refrigerant in heat pump air conditioners, the high carbon dioxide concentration after a leak poses a significant safety risk, necessitating the use of high-range, high-precision gas sensors.

[0022] Non-dispersive infrared spectroscopy (NDIR) is an important gas analysis method, commonly used for quantitative gas analysis and frequently applied in the design of gas sensors. The principle of using NDIR to analyze a gas is as follows: when infrared light illuminates the gas, the gas absorbs light at specific wavelengths. According to Beer-Lambert's absorption law, under ideal conditions, given the effective absorption path length and the absorption coefficient of the molecules at a specific wavelength, the concentration of the gas can be calculated using the ratio of the light signal before absorption to the light signal after absorption.

[0023] The gas sensor is defined to have a length direction L, a width direction W, and a height direction H, with the length direction L, width direction W, and height direction H being mutually perpendicular.

[0024] According to one possible embodiment of the gas sensor of this application, refer to Figures 1 to 8 As shown, a gas sensor includes a detection housing assembly 10 and a detection assembly 20, which are connected. The detection housing assembly 10 has a detection chamber 101, and the detection assembly 20 includes a light source 21 and a photodetector 22. The light source 21 is at least partially located in the detection chamber 101, and the photodetector 22 is at least partially located in the detection chamber 101.

[0025] The detection housing assembly 10 includes a first detection housing 11, which includes a first reflective surface 111. The light emitted by the light source 21 can be reflected to the photodetector 22 through the first reflective surface 111 at least.

[0026] The gas sensor is defined to have a height direction H, and the projection of the first reflective surface 111 on the projection plane perpendicular to the height direction H is a U-shaped surface.

[0027] In this application, the light emitted by the light source 21 can be reflected to the photodetector 22 through the first reflective surface 111. On the projection plane perpendicular to the height direction H of the gas sensor, the projection of the first reflective surface 111 is a U-shaped surface. Compared with the projection of the first reflective surface 111 as a U-shaped line segment, the reflection area of ​​the first reflective surface 111 is larger, thereby improving the reflection effect of the first reflective surface 111, increasing the light intensity reaching the photodetector 22, increasing the number of light rays reaching the photodetector 22, and thus improving the detection accuracy of the gas sensor.

[0028] The first reflecting surface 111 includes multiple sub-reflecting surfaces 1111, which are interconnected. The sub-reflecting surfaces 1111 have an arc surface structure. The first reflecting surface 111 formed by the interconnection of multiple arc surface sub-reflecting surfaces 1111 has a better reflection effect.

[0029] The multiple sub-reflective surfaces 1111 have different radii of curvature. The first reflective surface 111 formed by the interconnection of multiple arc-shaped sub-reflective surfaces 1111 with different radii of curvature has a better reflection effect, which further improves the light intensity reaching the photodetector 22 and increases the number of light rays reaching the photodetector 22, thereby further improving the detection accuracy of the gas sensor.

[0030] Reference Figures 3 to 6As shown, the detection assembly 20 includes a circuit board 23. A first detection housing 11 is connected to the circuit board 23 by bolts. Specifically, the first detection housing 11 has three first mounting holes arranged in a triangular pattern. The circuit board 23 has three second mounting holes. The first and second mounting holes mate with each other, and bolts pass through the second mounting holes and are tightly fitted to the hole walls of the first mounting holes, thus assembling the first detection housing 11 and the circuit board 23. A second detection housing 12 is located between the first detection housing 11 and the circuit board 23. The light source 21 and the photodetector 22 are both fixedly connected to the circuit board 23 and electrically connected to the circuit board 23. The first detection housing 11 includes a top surface 117 with a limiting groove 1171. The groove wall of the limiting groove 1171 is recessed from the top surface 117 away from the light source 21. A portion of the light source 21 is located in the limiting groove 1171, and the light source 21 is limited and fitted with the groove wall of the limiting groove 1171. Without the limiting groove 1171, the light source 21 might shake during use, which would adversely affect the detection accuracy of the gas sensor. By effectively limiting the light source 21 with the limiting groove 1171, the shaking of the light source 21 during use is reduced, thereby improving the detection accuracy of the gas sensor.

[0031] The detection housing assembly 10 includes a second detection housing 12, and the first detection housing 11 is connected to the second detection housing 12. The detection chamber 101 is located between the first detection housing 11 and the second detection housing 12. Both the first detection housing 11 and the second detection housing 12 are made of plastic, and the surfaces of the first detection housing 11 and the second detection housing 12 are coated with a metal conductive film, which has good reflective properties.

[0032] The first detection housing 11 is a one-piece structure, and the second detection housing 12 is a one-piece structure. It should be noted that the method of processing and forming into a one-piece structure is not specifically limited. It can be formed by one or a combination of one or more of the following processes: stamping, extrusion, casting, powder metallurgy, metal powder injection molding, 3D printing, etc. It can also be formed by stamping, extrusion, casting, powder metallurgy, or metal powder injection molding, and then machined. Alternatively, it can be formed directly by machining.

[0033] The second detection housing 12 has a first through hole 121 and a first notch 122. The first through hole 121 extends through both sides of the second detection housing 12 in the thickness direction, and the first notch 122 extends through both sides of the second detection housing 12 in the thickness direction. A portion of the light source 21 is located in the first notch 122 and passes through the first notch 122. A portion of the photodetector 22 is located in the first through hole 121.

[0034] Reference Figure 5 and Figure 6As shown, on the projection plane perpendicular to the height direction H, the projection of the light source 21 and the projection of the first reflecting surface 111 partially overlap. The first reflecting surface 111 is concave away from the light source 21 and extends towards the light source 21. The first reflecting surface 111 is connected to the wall of the limiting groove 1171. The first reflecting surface 111 has a large reflective area and good space utilization, thus improving its reflective effect. On the projection plane perpendicular to the height direction H, the projection of the first reflecting surface 111 is a U-shaped surface. The light source 21 is located in the U-shaped space enclosed by the first reflecting surface 111. The first reflecting surface 111 can reflect the light emitted by the light source 21 very well, further improving its reflective effect and thus improving the detection accuracy of the gas sensor.

[0035] The first detection housing 11 includes a second reflective surface 112, which has an arc-shaped structure. The second reflective surface 112 is spaced apart from the first reflective surface 111, ensuring that light emitted from the light source 21 is reflected by the second reflective surface 112 to the photodetector 22. On a projection plane perpendicular to the height direction H, the projection of the photodetector 22 and the projection of the second reflective surface 112 partially overlap. The second reflective surface 112 is located above the photodetector 22. Its arc-shaped structure allows for effective reflection of light emitted from the light source 21 to the photodetector 22, resulting in better reflection and improved detection accuracy of the gas sensor. Optionally, the angle between the second reflective surface 112 and the top surface 117 is between 30° and 60°; alternatively, an angle of approximately 45° provides better reflection.

[0036] Reference Figure 5 and Figure 6 As shown, the first detection housing 11 includes a third reflective surface 113 and a fourth reflective surface 114, which are symmetrically arranged and both have an arc-shaped structure. The third and fourth reflective surfaces 113 and 114 are spaced apart from the first reflective surface 111 and from the second reflective surface 112. Optionally, the angle between the third reflective surface 113 and the top surface 117 is approximately 90°, and the angle between the fourth reflective surface 114 and the top surface 117 is also approximately 90°. Both the third and fourth reflective surfaces 113 and 114 can reflect light emitted from the light source 21. The arrangement of the third and fourth reflective surfaces 113 and 114 increases the number of reflections of light in the detection chamber 101, thereby increasing the optical path and improving the detection accuracy of the gas sensor.

[0037] Reference Figure 5 and Figure 6As shown, the first detection housing 11 includes a fifth reflective surface 115 and a sixth reflective surface 116. The fifth reflective surface 115 is located between the third reflective surface 113 and the sixth reflective surface 116, both of which are connected to it. The sixth reflective surface 116 is located between the fourth reflective surface 114 and the fifth reflective surface 115, both of which are connected to it. The fifth and sixth reflective surfaces 115 and 116 are spaced apart from the first reflective surface 111 and from the second reflective surface 112. The third, fifth, sixth, and fourth reflective surfaces 113, 115, 116, and 114 are connected sequentially. The fifth reflective surface 115 and 116 are either planar or curved surfaces. Optionally, the angle between the fifth reflective surface 115 and the top surface 117 is approximately 90°, and the angle between the sixth reflective surface 116 and the top surface 117 is also approximately 90°. Both the fifth reflective surface 115 and the sixth reflective surface 116 can reflect the light emitted by the light source 21. The arrangement of the fifth reflective surface 115 and the sixth reflective surface 116 can further increase the number of reflections of the light in the detection chamber 101, thereby further increasing the optical path of the light. The light emitted by the light source 21 reaches the photodetector 22 after multiple reflections in the detection chamber 101, thus improving the detection accuracy of the gas sensor. On the projection plane perpendicular to the height direction H, the third reflective surface 113, the fifth reflective surface 115, the sixth reflective surface 116, and the fourth reflective surface 114 are connected in sequence to form a U-shaped projection profile.

[0038] The detection component 20 also includes a signal transmitter, a signal conditioner, a central processing unit, and a communication interface. The signal transmitter, signal conditioner, central processing unit, and communication interface are all located on the circuit board 23. The signal transmitter, signal conditioner, and central processing unit are all electrically or signal-connected to the communication interface.

[0039] When the gas sensor is working, the light source 21 emits infrared light, which is reflected by the first reflecting surface 111 to at least one of the third reflecting surface 113, the fourth reflecting surface 114, the fifth reflecting surface 115, and the sixth reflecting surface 116, and then reflected to the second reflecting surface 112, which in turn reflects the light to the photodetector 22. In other words, the light source 21 emits infrared light, which is reflected by the first reflecting surface 111. The light reflected by the first reflecting surface 111 undergoes one or more reflections by at least one of the third reflecting surface 113, the fourth reflecting surface 114, the fifth reflecting surface 115, and the sixth reflecting surface 116, and then reflected to the second reflecting surface 112, which in turn reflects the light to the photodetector 22. When gas in the air enters the detection chamber 101, the gas absorbs infrared light of the corresponding frequency, resulting in an electrical signal. The signal changes, and the concentration of the measured gas CO2 is output. The multiple reflections of the light in the detection chamber 101 increase the optical path and coverage area, thereby improving the detection accuracy of the gas sensor.

[0040] Optionally, the partial optical path for the infrared light emitted by the light source 21 is: Light source 21 → First reflecting surface 111 → Third reflecting surface 113 → Fourth reflecting surface 114 → Second reflecting surface 112 → Photodetector 22. Alternatively, the partial optical path for the infrared light emitted by the light source 21 is: Light source 21 → First reflecting surface 111 → Sixth reflecting surface 116 → Second reflecting surface 112 → Photodetector 22. Alternatively, the partial optical path for the infrared light emitted by the light source 21 is: Light source 21 → First reflecting surface 111 → Fifth reflecting surface 115 → Second reflecting surface 112 → Photodetector 22. Examples are not provided here.

[0041] Reference Figures 3 to 6 As shown, the first detection housing 11 has two vent openings 118, spaced apart, which communicate with the detection chamber 101 and the external gas of the detection housing assembly 10. The top surface 117 has multiple first vent holes 1172, spaced apart. The first vent holes 1172 are circular, but optionally can be oblong, square, elliptical, etc., without specific limitations. Along the length direction L, the multiple first vent holes 1172 are evenly spaced; along the width direction W, the multiple first vent holes 1172 are also evenly spaced. The multiple first vent holes 1172 are arranged in a square pattern. The first vent holes 1172 penetrate both sides of the top surface 117 in the thickness direction, communicating with the detection chamber 101 and the external gas of the detection housing assembly 10. The arrangement of the vent opening 118 and multiple first vent holes 1172 ensures good gas communication between the detection chamber 101 and the detection housing assembly 10.

[0042] The gas sensor includes a waterproof and breathable membrane 40. On a projection plane perpendicular to the height direction H, the projection of the waterproof and breathable membrane 40 covers the projection of the first vent hole 1172 and the vent opening 118. In other words, the waterproof and breathable membrane 40 covers the first vent hole 1172 and the vent opening 118. Without the waterproof and breathable membrane 40, external moisture from the detection housing assembly 10 would enter the detection chamber 101, adversely affecting the detection accuracy of the gas sensor and also negatively impacting electronic components. The waterproof and breathable membrane 40 prevents external moisture from entering the detection chamber 101, ensuring the dryness of the gas entering the detection chamber 101, thereby improving the detection accuracy and reliability of the gas sensor.

[0043] Reference Figures 3 to 6 and Figure 8 As shown, the gas sensor includes a housing assembly 30, which includes a first housing 31 and a second housing 32. The first housing 31 and the second housing 32 are connected, optionally by laser welding. The first housing 31 is fixedly connected to the circuit board 23. Specifically, the first housing 31 has three third mounting holes arranged in a triangle. The circuit board 23 has three fourth mounting holes. The third mounting holes mate with the fourth mounting holes, and bolts pass through the fourth mounting holes and are tightly fitted to the hole walls of the third mounting holes, thus assembling the first housing 31 and the circuit board 23. The first housing 31 and the circuit board 23 are connected by bolts. The housing assembly 30 has a mounting cavity 301, where both the detection housing assembly 10 and the detection assembly 20 are located. Both the first housing 31 and the second housing 32 are made of plastic and are integral structures.

[0044] The first outer casing 31 has multiple second vent holes 311 and third vent holes 312. The second vent holes 311 extend through both sides of the bottom wall thickness direction of the first outer casing 31, and the third vent holes 312 extend through both sides of the bottom wall thickness direction of the first outer casing 31. The multiple second vent holes 311 are spaced apart. The second vent holes 311 are oblong; optionally, they can be circular, square, elliptical, etc., without specific limitations. Along the length direction L, the multiple second vent holes 311 are evenly spaced; along the width direction W, the multiple second vent holes 311 are also evenly spaced. The multiple second vent holes 311 are arranged in a square pattern. Multiple third vent holes 312 are spaced apart. The third vent holes 312 are elongated holes; optionally, the second vent holes 311 can be circular, square, elliptical, etc., without specific limitations. Along the width direction W, the multiple third vent holes 312 are evenly spaced. The second vent 311 is connected to the vent opening 118 and is connected to the external gas of the gas sensor. The third vent 312 is connected to the first vent 1172 and is also connected to the external gas of the gas sensor. One third vent 312 corresponds to multiple first vents 1172. Optionally, one third vent 312 is configured to correspond to four first vents 1172.

[0045] On a projection plane perpendicular to the height direction H, the projection of the waterproof and breathable membrane 40 covers the projection of the second vent 311, and the projection of the waterproof and breathable membrane 40 covers the projection of the third vent 312. In other words, the waterproof and breathable membrane 40 covers the second vent 311 and the third vent 312. The waterproof and breathable membrane 40 can prevent external moisture from entering the mounting cavity 301 of the gas sensor, ensuring the dryness of the gas entering the mounting cavity 301, reducing adverse effects on the electronic components in the mounting cavity 301, thereby improving the reliability and detection accuracy of the gas sensor.

[0046] It should be understood that the integral structure in this application refers to a component manufactured from a single piece of material using processes such as stamping, extrusion, and machining, without the use of brazing, gluing, or other joining processes. The methods of fixing and installing together in this application include, but are not limited to, at least one of brazing, gluing, or bracket fixing. It should be understood that in this application, the "connection" between two components can be a direct connection or an indirect connection through other components.

[0047] The technical solutions described in this application should be understood by those skilled in the art. For example, directional descriptions such as "front," "back," "left," "right," "up," and "down" are only used to describe the relationship between objects and are not substantive limitations. "Multiple" means at least two or more.

[0048] The above examples illustrate the principles and implementation methods of the present invention. These embodiments are merely illustrative and intended to aid in understanding the method and core concepts of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A gas sensor, characterized in that, The device includes a detection housing assembly (10) and a detection assembly (20), the detection housing assembly (10) and the detection assembly (20) being connected. The detection housing assembly (10) has a detection chamber (101), and the detection assembly (20) includes a light source (21) and a photodetector (22), the light source (21) being at least partially located in the detection chamber (101), and the photodetector (22) being at least partially located in the detection chamber (101). The detection housing assembly (10) includes a first detection housing (11), the first detection housing (11) includes a first reflective surface (111), and the light emitted by the light source (21) can be reflected to the photodetector (22) at least through the first reflective surface (111); The gas sensor is defined to have a height direction (H), and the projection of the first reflective surface (111) on a projection plane perpendicular to the height direction (H) is a U-shaped surface.

2. The gas sensor as described in claim 1, characterized in that, On the projection plane perpendicular to the height direction (H), the projection of the light source (21) and the projection of the first reflecting surface (111) partially overlap; The first reflective surface (111) includes a plurality of sub-reflective surfaces (1111), which are interconnected. The sub-reflective surfaces (1111) have an arc surface structure and the radii of curvature of the plurality of sub-reflective surfaces (1111) are different.

3. The gas sensor as described in claim 2, characterized in that, The first detection housing (11) includes a second reflective surface (112), which is an arc-shaped structure. The second reflective surface (112) is spaced apart from the first reflective surface (111), and the light emitted by the light source (21) can be reflected to the photodetector (22) at least through the second reflective surface (112). On the projection plane perpendicular to the height direction (H), the projection of the photodetector (22) and the projection of the second reflective surface (112) partially overlap.

4. The gas sensor as described in claim 3, characterized in that, The first detection housing (11) includes a third reflective surface (113) and a fourth reflective surface (114), the third reflective surface (113) and the fourth reflective surface (114) are symmetrically arranged, and both the third reflective surface (113) and the fourth reflective surface (114) are arc-shaped structures; Both the third reflective surface (113) and the fourth reflective surface (114) can reflect the light emitted by the light source (21).

5. The gas sensor as described in claim 4, characterized in that, The first detection housing (11) includes a fifth reflective surface (115) and a sixth reflective surface (116). The fifth reflective surface (115) is located between the third reflective surface (113) and the sixth reflective surface (116). The third reflective surface (113) and the sixth reflective surface (116) are both connected to the fifth reflective surface (115). The sixth reflective surface (116) is located between the fourth reflective surface (114) and the fifth reflective surface (115). The fourth reflective surface (114) and the fifth reflective surface (115) are both connected to the sixth reflective surface (116). Both the fifth reflective surface (115) and the sixth reflective surface (116) can reflect the light emitted by the light source (21).

6. The gas sensor according to any one of claims 1 to 5, characterized in that, The detection component (20) includes a circuit board (23), the first detection housing (11) is connected to the circuit board (23), the light source (21) and the photodetector (22) are both fixedly connected to the circuit board (23), and the light source (21) and the photodetector (22) are both electrically connected to the circuit board (23); The first detection housing (11) includes a top part (117), the top part (117) has a limiting groove (1171), the groove wall of the limiting groove (1171) is recessed from the top part (117) in a direction away from the light source (21), a portion of the light source (21) is located in the limiting groove (1171), and the light source (21) is limited and engaged with the groove wall of the limiting groove (1171).

7. The gas sensor as described in claim 6, characterized in that, The first detection housing (11) has two vent openings (118), which are spaced apart. The vent openings (118) are connected to the detection chamber (101) and to the external gas of the detection housing assembly (10). The top surface (117) has a plurality of first vent holes (1172), which are spaced apart. The first vent holes (1172) penetrate both sides of the top surface (117) in the thickness direction. The first vent holes (1172) are connected to the detection chamber (101) and to the external gas of the detection housing assembly (10).

8. The gas sensor as described in claim 7, characterized in that, The gas sensor includes a waterproof and breathable membrane (40). On a projection plane perpendicular to the height direction (H), the projection of the waterproof and breathable membrane (40) covers the projection of the first vent (1172) and the projection of the vent opening (118).

9. The gas sensor as described in claim 8, characterized in that, The gas sensor includes a housing assembly (30), which includes a first housing (31) and a second housing (32). The first housing (31) and the second housing (32) are connected. The first housing (31) is fixedly connected to the circuit board (23). The housing assembly (30) has a mounting cavity (301). The detection housing assembly (10) and the detection assembly (20) are both located in the mounting cavity (301). The detection housing assembly (10) includes a second detection housing (12), the first detection housing (11) is connected to the second detection housing (12), and the detection chamber (101) is located between the first detection housing (11) and the second detection housing (12).

10. The gas sensor as described in claim 9, characterized in that, The first outer shell (31) has a plurality of second vent holes (311) and third vent holes (312). The second vent holes (311) penetrate through both sides of the bottom wall thickness direction of the first outer shell (31), and the third vent holes (312) penetrate through both sides of the bottom wall thickness direction of the first outer shell (31). The plurality of second vent holes (311) are spaced apart, and the plurality of third vent holes (312) are spaced apart. The second vent (311) is connected to the vent opening (118), the second vent (311) is connected to the external gas of the gas sensor, the third vent (312) is connected to the first vent (1172), and the third vent (312) is connected to the external gas of the gas sensor. On the projection plane perpendicular to the height direction (H), the projection of the waterproof and breathable membrane (40) covers the projection of the second vent (311), and the projection of the waterproof and breathable membrane (40) covers the projection of the third vent (312). The second detection housing (12) has a first through hole (121) and a first notch (122). The first through hole (121) penetrates both sides of the second detection housing (12) in the thickness direction, and the first notch (122) penetrates both sides of the second detection housing (12) in the thickness direction. The second detection housing (12) is located between the first detection housing (11) and the circuit board (23). A portion of the light source (21) is located in the first notch (122), and a portion of the photodetector (22) is located in the first through hole (121).

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