JP2003329631A - Gas detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a detection element of gas sensor from being poisoned with silicon. <P>SOLUTION: In a gas detection system, an air offgas discharged from a fuel cell is introduced into a gas detection chamber 35 in order to detect gaseous hydrogen with hydrogen sensor 25 installed on an air discharge path 22 and the hydrogen in the offgas flowing through the discharge path 22 is detected by the hydrogen sensor 25. On a cylindrical part 34 of the hydrogen sensor 25, a silicon trap 50 is mounted. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas detection system for detecting a gas to be detected by a gas sensor.

[0002]

2. Description of the Related Art As a conventional gas sensor, a gas contact combustion type gas sensor is known. This gas contact combustion type gas sensor is configured to include a detection element to which a catalyst is attached and a temperature compensation element to which a catalyst is not attached, and utilizes the heat of combustion when the gas to be detected comes into contact with the catalyst. Then, the gas concentration of the gas to be detected is detected from the difference in electric resistance between the detection element and the temperature compensation element.

[0003]

However, when such a gas sensor is provided in the flow path for passing the gas to be inspected, silicon in the material such as the sealing material may be mixed in the gas to be inspected. If the detection element is exposed to this silicon during the catalytic reaction, the catalyst is poisoned, and as a result, the detection element may deteriorate and the detection accuracy may decrease. Therefore, the present invention provides a gas detection system having a simple structure and capable of preventing silicon poisoning of a gas sensor.

[0004]

In order to solve the above-mentioned problems, the present invention provides a detection element (for example, a detection element 42 in the embodiment described later) and a temperature compensation element (for example, a temperature in the embodiment described later). Compensation element 43) and a gas detection chamber (for example, gas detection chamber 35 in the embodiment to be described later) are introduced with a gas to be inspected (for example, air off gas in the embodiment to be described later) to be detected gas (for example, gas to be detected). , A gas sensor (for example, hydrogen sensor 25 in the embodiment to be described later) that detects hydrogen gas in the embodiment to be described later, and a gas channel for the gas to be inspected (for example, an air discharge path 22 in the embodiment to be described later). Installed in, in the gas detection system for detecting the gas to be detected in the gas to be inspected flowing through the flow path with the gas sensor,
A trap channel (for example, trap channels 60, 68, 85, 96 in the embodiments described later) through which a gas to be inspected flows upstream of the gas detection chamber, and silicon removal provided on the inner wall surface of the trap channel. A silicon trap (for example, silicon traps 50, 80, 90 in the embodiments described later) provided with a material (for example, catalyst layers 61, 72, 86, 98 in the embodiments described below). . With this configuration, the inspection target gas from which silicon has been removed by the silicon trap flows into the gas detection chamber of the gas sensor, so that the gas sensor can be prevented from being poisoned by silicon. Also, the structure of the silicon trap is simplified.

Further, in the present invention, the silicon removing material may be composed of a catalyst (for example, platinum in the embodiments described later). With this configuration,
Silicon contained in the gas to be inspected adheres to the catalyst, and as a result, silicon can be removed from the gas to be inspected.

Further, in the present invention, a collision portion (for example, an outer cylinder portion 51, a flange portion 53, an intermediate flange portion 55, a baffle plate 57, a baffle plate 57, and the like in the embodiment described later on which the gas to be inspected collides with the trap channel. 97, the standing wall 71,
End plates 81a, 81b, 91a, 91b, closed end plate 84
a) may be provided, and the silicon removing material may be provided at the collision part. By configuring in this way,
The chances that silicon contained in the gas to be inspected will come into contact with the silicon removing material increases, and it becomes possible to sufficiently remove silicon.

In the present invention, the silicon trap (for example, the silicon trap 50 in the embodiment described later) has a gas inlet (for example, the embodiment described later) for introducing the gas to be inspected into the gas detection chamber. It can be attached so as to cover the gas introduction port 37). With this configuration, the silicon trap can be made compact and integrated with the gas sensor.

Further, in the present invention, the trap channel has a starting end (for example, a gas introducing port 66 in an embodiment described later) opening for introducing gas and an ending end (for example, described later for opening gas). The gas outlet 67) in the embodiment may be provided. With this configuration, the gas to be inspected easily flows in the trap channel, and the detection accuracy of the gas to be detected is improved.

In the present invention, the silicon trap (for example, 80, 9 in the embodiment described later) is used.
0) can be provided in the flow path of the gas to be inspected (for example, the bypass path 27 in the embodiment described later) located upstream of the installation position of the gas sensor. With this structure, the degree of freedom in designing the silicon trap is increased.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a gas detection system according to the present invention will be described below with reference to the drawings of FIGS. In the embodiments described below,
The gas sensor is an aspect as a hydrogen sensor that detects hydrogen gas as a gas to be detected, and is used to confirm that hydrogen gas does not leak into the cathode off gas (gas to be inspected) discharged from the cathode of the fuel cell. It is an aspect of a gas detection system.

[First Embodiment] First, a first embodiment of the gas detection system according to the present invention will be described with reference to the drawings of FIGS. 1 to 3. FIG. 1 is a configuration diagram of a fuel cell system including a hydrogen sensor 25 as a gas sensor. In this embodiment, the fuel cell system is mounted in a vehicle such as an electric vehicle driven by the power generated by the fuel cell.

The fuel cell 2 comprises a stack formed by stacking a plurality of cells formed by sandwiching a solid polymer electrolyte membrane, such as a solid polymer ion exchange membrane, between an anode and a cathode. In this fuel cell 2, hydrogen gas is supplied as a fuel to the anode through a hydrogen supply path 11, and air is supplied as an oxidant to the cathode through an air supply path 21, and is generated by a catalytic reaction at the anode. The generated hydrogen ions move to the cathode through the solid polymer electrolyte membrane, cause an electrochemical reaction with oxygen in the cathode to generate power, and generate water.
Then, unreacted hydrogen gas, that is, hydrogen off gas (anode off gas) is discharged from the hydrogen discharge path 12 and reused through a circulation path (not shown), and reacted air, that is, air off gas (cathode off gas) is discharged to air. It is discharged from the line 22 to the outside of the system.

A gas contact combustion type hydrogen sensor 25 is attached to the upper side in the direction of gravity in the middle of the air discharge path 22, and it is confirmed by this hydrogen sensor 25 that hydrogen gas does not exist in the air off gas. You can do it. However, in the air off gas, silicon in the material such as the sealing material used in the fuel cell 2 and the air discharge path 22 may be mixed in the gas to be inspected. 2 is a plan view of the hydrogen sensor 25, and FIG. 3 is a cross-sectional view taken along the line I-I of FIG. 2, showing the mounting state of the hydrogen sensor 25. The air exhaust passage 22 has a mounting seat 23 for the hydrogen sensor 25.
And the mounting hole 24 is provided in the peripheral wall of the air discharge path 22. In the hydrogen sensor 25, for example, a flange portion 31 is formed on a case 30 made of polyphenylene sulfide, and a collar 32 is attached to the flange portion 31, and a bolt 33 is inserted into the collar 32 to insert the air exhaust passage 22. It is fastened and fixed to the mounting seat 23.

A tubular portion 34 is formed in the case 30, a cap-type silicon trap 50 is mounted on the tubular portion 34, and the tubular portion 34 and the silicon trap 50 are inserted into the mounting holes 24. . The inside of the tubular portion 34 is formed as a gas detection chamber 35, and the tip end side of the tubular portion 34, that is, the end portion of the gas detection chamber 35 on the inner side of the air discharge path 22 is formed as a gas inlet 37. There is. The sensor body 39 is mounted inside the tubular portion 34.

The sensor body 39 is the tubular portion 3 of the case 30.
An annular base 40 made of, for example, polyphenylene sulfide is provided at a position closing the proximal end side of 4, and a metal-made cylindrical peripheral wall portion having a height reaching the tip of the cylindrical portion 34 is provided on the outer peripheral portion. 41 is provided, and a pair of a detection element 42 to which a catalyst such as platinum is attached and a temperature compensation element 43 to which a catalyst is not attached are provided at the same height from the base 40 at a predetermined interval. The detection element 42 is a well-known element, and utilizes the heat of combustion when hydrogen, which is the gas to be detected, comes into contact with a catalyst such as platinum, and detects the temperature of the detection element 42 that has become high due to the combustion of hydrogen and the ambient temperature. By utilizing the difference in electric resistance between the temperature compensating element 43 and the temperature compensating element 43, the hydrogen gas concentration is detected, and the output current corresponding to the hydrogen gas concentration is output to the control device 29 (see FIG. 1) as an output signal.

The silicon trap 50 has an outer cylinder portion 51.
The hydrogen sensor 2 is provided inside the outer cylinder portion 51 on the base end side.
By fitting the tubular portion 34 of No. 5, the silicon trap 50 is attached to the hydrogen sensor 25, and the base end surface of the outer tubular portion 51 is abutted against the bottom surface of the case 30. The outer peripheral surface of the tubular portion 34 and the inner peripheral surface of the outer tubular portion 51 are sealed by the seal material 38, and the outer peripheral surface of the outer tubular portion 51 and the inner peripheral surface of the mounting hole 24 are sealed by the seal material 52.
A flange portion 53 is formed toward the inner side at the tip of the outer cylinder portion 51, and a gas introduction cylinder 54 that bends at a right angle to the base end side of the outer cylinder portion 51 is formed at the inner peripheral portion of the flange portion 53. The air off gas flowing through the air discharge passage 22 can be introduced into the outer cylinder portion 51 from the gas introduction cylinder 54. In addition,
The flange portion 53 is set flush with the inner wall of the air discharge passage 22, and the gas introduction cylinder 54 is oriented in a direction perpendicular to the air off gas flowing through the air discharge passage 22.

Further, the outer tubular portion 51 has an intermediate flange portion 55 projecting inwardly from the inner peripheral surface thereof, and the intermediate flange portion 55 has a distal end of the tubular portion 34 of the hydrogen sensor 25 and the peripheral wall portion 41. The tip of is hitting. A fitting cylinder portion 56 that is bent at a right angle toward the base end side of the outer cylinder portion 51 is formed on the inner peripheral portion of the intermediate flange portion 55. The fitting cylinder portion 56 is fitted inside the peripheral wall portion 41. ing. Further, inside the outer tubular portion 51, a baffle 57 suspended from the fitting tubular portion 56 by a support arm 58 is installed between the flange portion 53 and the intermediate flange portion 55. The outer peripheral portion of the baffle plate 57 is located substantially at the center in the radial direction of the flange portion 53 and the intermediate flange portion 55, and the outer peripheral portion of the baffle plate 57 is a tubular portion 59 that is bent at a right angle in the direction toward the flange portion 53. Are formed.

A labyrinth-shaped trap passage 60 through which air off gas flows is formed inside the outer cylinder portion 51 and on the tip side of the cylinder portion 59. In the trap channel 60, the gas flowing in from the gas introducing cylinder 54 collides with the baffle plate 57 to change the flow direction to the radially outward direction,
Further, the flow direction is changed to the direction toward the flange portion 53 by the tubular portion 59, and then the flange portion 53 is changed.
And the direction of the flow is changed to the outside in the radial direction, and further, the direction of the flow is changed to the direction toward the intermediate flange 55 by the inner peripheral surface of the outer tubular portion 51. It collides with the portion 55 to change the direction of flow to the radially inner side, and finally is introduced into the tubular portion 36 from the fitting tubular portion 56 via the gas introduction port 37.

In the silicon trap 50, a catalyst (silicon removing material) such as platinum or palladium or a compound thereof is formed at a portion on the inner wall surface of the trap channel 60 where the air off-gas collides to change the flow direction. Is provided. More specifically, the catalyst layer 61 is provided on the inner surface of the flange portion 53, the surface of the intermediate flange portion 55 that faces the flange portion 53, and the surface of the baffle plate 57 that faces the flange portion 53, respectively. ing. In this embodiment, the flange portion 53, the intermediate flange portion 55 and the baffle plate 57 constitute a collision portion against which the air off gas collides, and the catalyst layer 61 is provided in this collision portion. As described above, in the first embodiment, the silicon trap 50 is installed upstream of the gas detection chamber 35 and attached to the hydrogen sensor 25 so as to cover the gas introduction port 37.

In the gas detection system thus constructed, when the air off gas flowing through the air exhaust passage 22 flows into the outer cylinder portion 51 from the gas introduction cylinder 54 of the silicon trap 50, the air off gas is trapped by the trap passage 60. While flowing toward the gas introduction port 37 of the hydrogen sensor 25, silicon contained in the air off gas collides with one of the catalyst layers 61 and adheres to the catalyst layer 61. As a result, silicon can be removed from the air off gas, and the air off gas that does not contain silicon can be removed from the gas detection chamber 35.
Come to enter. In particular, since the catalyst layer 61 is provided at the site where the air off gas collides, the chances that the silicon contained in the air off gas will come into contact with the catalyst layer 61 is increased, and the silicon can be sufficiently removed.

Therefore, the detection element 4 of the hydrogen sensor 25
The catalyst attached to 2 is not poisoned by silicon, and as a result, the hydrogen sensor 25 can be prevented from deterioration and the detection accuracy of the hydrogen sensor 25 can be kept high for a long period of time. . In addition, in the first embodiment, the silicon trap 50 is attached so as to cover the gas introduction port 37.
Can be made compact and the hydrogen sensor 2
It can be integrated with 5 and is easy to handle.

[Second Embodiment] Next, a second embodiment of the gas detection system according to the present invention will be described with reference to the drawing of FIG. Also in the gas detection system of the second embodiment, the first feature is that the cap-type silicon trap 50 is attached to the tubular portion 34 of the hydrogen sensor 25.
It is the same as the embodiment of. However, in the second embodiment, the intermediate flange portion 5 of the silicon trap 50 is
The end surface of 5 is set flush with the inner wall of the air discharge passage 22, and the outer cylinder portion 51 located on the tip side of the intermediate flange portion 55 is installed so as to project into the air discharge passage 22. Hereinafter, a portion different from that of the first embodiment, that is, the air exhaust passage 22 in the silicon trap 50 will be described.
The part protruding inside will be described. Since the portion of the silicon trap 50 that is inserted into the mounting hole 24 of the air exhaust passage 22 is the same as that of the first embodiment, the same reference numerals are given to the same portions in the drawings for description. Omit it.

In the silicon trap 50 according to the second embodiment, the tip of the outer cylinder portion 51 is closed by the tip plate 65. Further, a gas inlet 66 is formed on the outer peripheral surface of the outer cylinder portion 51 on the tip end side and on the upstream side in the flow direction of the air offgas flowing through the air discharge passage 22, and is the outer peripheral surface of the middle portion of the outer cylinder portion 51. A gas outlet 67 is formed on the downstream side in the flow direction of the air off gas, and the gas inlet 66 and the gas outlet 67 are connected by a trap channel 68 formed inside the outer cylinder part 51. In other words, the trap flow path 68 has a gas introduction port 66 opened for gas introduction as a start end and a gas discharge port 67 opened for gas discharge as an end.

The trap passage 68 is meandering in the outer tubular portion 51 by the two partition walls 69 and 70 extending horizontally inward from the inner peripheral surface of the outer tubular portion 51 while meandering in the outer tubular portion 51.
Is formed to approach. Further, a standing wall portion 71 for guiding the gas to the gas introduction port 37 is formed on the surface of the partition wall 69 provided on the upper side facing the intermediate flange portion 55 so as to project upward. Then, the gas collides with the inner wall surface of the outer tubular portion 51 to change the flow direction to 18
A catalyst layer 72 made of platinum, palladium, or a compound thereof is provided on the portion to be changed by 0 ° and on the upstream side wall surface of the standing wall portion 71. In this embodiment, the inner wall surface of the outer tubular portion 51 and the standing wall portion 71 constitute a collision portion,
The catalyst layer 72 is provided at this collision portion.

In the gas detection system constructed as described above, the air off gas flowing through the air discharge passage 22 flows from the gas introduction port 66 of the silicon trap 50 to the trap passage 6.
When the air flows into the trap channel 68,
While flowing toward the gas inlet 37 of the hydrogen sensor 25, silicon contained in the air off gas collides with one of the catalyst layers 72 and adheres to the catalyst layer 72. In particular, since the catalyst layer 72 is provided at the site where the air off gas collides, the chances that the silicon contained in the air off gas will come into contact with the catalyst layer 72 will be increased, and the silicon can be sufficiently removed. Thereby, silicon can be removed from the air off-gas, and the air off-gas not containing silicon is guided by the upright wall portion 71 to flow toward the gas introduction port 37. Then, a part of the air off gas containing no silicon enters the gas detection chamber 35.

Therefore, the detection element 4 of the hydrogen sensor 25
The catalyst attached to 2 is not poisoned by silicon, and as a result, the hydrogen sensor 25 can be prevented from deterioration and the detection accuracy of the hydrogen sensor 25 can be kept high for a long period of time. . And the gas detection chamber 3
The air off-gas that has not been introduced into the chamber 5 and the air off-gas discharged from the gas detection chamber 35
The gas is discharged to the air discharge passage 22 from the gas discharge port 67 which is the end of 8. Thus, in the second embodiment,
Since the start end of the trap flow path 68 of the silicon trap 50 is opened as the gas introduction port 66 and the end end is opened as the gas discharge port 67, the air off gas easily flows through the trap flow path 68. Moreover, the gas in the gas detection chamber 35 is easily replaced by the guiding function of the standing wall portion 71. As a result, the detection accuracy of the hydrogen sensor 25 is improved. Also,
Also in the gas detection system of the second embodiment, the silicon trap 50 is attached so as to cover the gas introduction port 37 as in the case of the first embodiment, so that the silicon trap 50 can be made compact. Moreover, it can be integrated with the hydrogen sensor 25 and is easy to handle.

[Third Embodiment] Next, a third embodiment of the gas detection system according to the present invention will be described with reference to the drawings of FIGS. 5 and 6. In the above-described first and second embodiments, the cap-type silicon trap 50 is attached to the cylindrical portion 34 of the hydrogen sensor 25, but in the third embodiment, In this embodiment, a silicon trap is provided in the air off-gas passage located upstream of the hydrogen sensor 25.

FIG. 5 is a block diagram of the essential parts of a gas detection system according to the third embodiment. A throttle 26 is provided in the middle of the air discharge path 22, and an upstream side and a downstream side of the throttle 26 are connected by a bypass path 27 for sensing, and a part of the air off gas flowing through the air discharge path 22 is bypassed by the bypass path 27. Is also flowing. Further, the silicon trap 80 and the hydrogen sensor 25 are installed in the bypass passage 27, and the silicon trap 80 is arranged upstream of the hydrogen sensor 25. Hydrogen sensor 2
The configuration of No. 5 corresponds to the hydrogen sensor 25 of the first embodiment.
Since it is the same as the above, its explanation is omitted.

As shown in the sectional view of FIG. 6, the silicon trap 80 has a cylindrical main body 81, and an inlet pipe 82 is fixedly penetrated to an end plate 81a on one end side of the main body 81.
The tip of the inlet pipe 82 is located in the middle of the main body 81, and the outlet pipe 83 is connected to the end plate 81b on the other end side of the main body 81. Further, in the main body 81, a tubular body 84 having only one end opened is provided so as to cover the distal end side of the inlet pipe 82 with a gap, and the closed end plate 84 of the tubular body 84 is provided.
a is opposed to the open end 82a of the inlet pipe 82.

In this silicon trap 80, the inside of the main body 81 is formed in the trap channel 85, and the trap channel 85 is meandered by being partitioned by the inlet pipe 82 and the cylindrical body 84 to form a labyrinth shape. There is. Then, the inner surface of the closed end plate 84 a of the tubular body 84, the inner surface of the one end side end plate 81 a of the main body 81, and the other end side end plate 81 of the main body 81.
A catalyst layer 86 made of platinum, palladium, or a compound thereof is provided on the inner surface of b. These catalyst layers 8
The portion where 6 is provided is a portion where the gas flowing through the trap channel 85 collides and changes the flow direction. In this embodiment, both end plates 81a and 81b of the main body 81 and the tubular body 8 are provided.
The closed end plate 84a of No. 4 constitutes a collision portion, and the catalyst layer 86 is provided in this collision portion.

In the gas detection system according to the third embodiment, a part of the air off gas flowing through the air exhaust passage 22 flows into the bypass passage 27 and flows through the silicon trap 80. Then, while the air off-gas flowing from the inlet pipe 82 of the silicon trap 80 flows through the trap passage 85 toward the outlet pipe 83, the silicon contained in the air off-gas collides with one of the catalyst layers 86. And adheres to the catalyst layer 86. In particular, since the catalyst layer 86 is provided at the site where the air off gas collides, the chances that the silicon contained in the air off gas will come into contact with the catalyst layer 86 increases, and the silicon can be sufficiently removed. As a result, silicon can be removed from the air off-gas, and the air off-gas containing no silicon flows to the downstream where the hydrogen sensor 25 is installed. Then, the air off gas containing no silicon is the hydrogen sensor 2.
The gas detection chamber 35 of No. 5 enters.

Therefore, the detection element 4 of the hydrogen sensor 25
The catalyst attached to 2 is not poisoned by silicon, and as a result, the hydrogen sensor 25 can be prevented from deterioration and the detection accuracy of the hydrogen sensor 25 can be kept high for a long period of time. . In the third embodiment, the silicon trap 80 is not directly attached to the cylindrical portion 34 of the hydrogen sensor 25, but is provided in the bypass passage 27 located upstream of the installation position of the hydrogen sensor 25. There is an advantage that the degree of freedom in designing the trap 80 is increased, the outer dimensions of the silicon trap 80, the surface area of the catalyst layer 86, and the like can be freely set, and the silicon removing ability can be increased.

[Fourth Embodiment] Next, a fourth embodiment of the gas detection system according to the present invention will be described with reference to the drawing of FIG. The gas detection system of the fourth embodiment is the same as that of the third embodiment in that a silicon trap is provided in the middle of the bypass passage 27 located upstream of the hydrogen sensor 25, and the difference is that It is in the internal structure of the trap.

The silicon trap 90 according to the fourth embodiment will be described below with reference to FIG. In the silicon trap 90, one end side end plate 91 of the main body 91
The inlet pipe 92 is connected to a, and the other end side end plate 91 of the main body 91 is connected.
An outlet pipe 93 is connected to b. The inside of the main body 91 is formed into one flow path meandering by the partition plates 94 and 95 extending from the inner surfaces of the end plates 91a and 91b, and this flow path is a trap flow path 96. This trap channel 96
Has one end connected to the inlet pipe 92 and the other end connected to the outlet pipe 93.

The inner peripheral surface of the main body 91 and the partition plate 9
A large number of baffle plates (collision portions) 97 that incline toward the downstream side in the flow direction of the gas flowing through the trap passages 96 are provided at 4 and 95. A catalyst layer 98 made of platinum, palladium, or a compound thereof is provided on the inner surface of each of the end plates 91a and 91b and the surface of each baffle plate 97 on the upstream side in the gas flow direction. The portion where these catalyst layers 98 are provided is a portion where the gas flowing through the trap channel 96 collides and changes the direction of the flow. In this embodiment, the end plates 91a and 91b and each baffle plate 97 form a collision portion. The catalyst layer 98 is provided at this collision portion.

Also in this silicon trap 90, the air off gas flowing in from the inlet pipe 92 is trap passage 96.
While flowing toward the outlet pipe 93, the silicon contained in the air off gas collides with one of the catalyst layers 98 and adheres to the catalyst layer 98. In particular, since the catalyst layer 98 is provided at the site where the air off gas collides, the chances that the silicon contained in the air off gas will come into contact with the catalyst layer 98 increases, and the silicon can be sufficiently removed. As a result, the silicon can be removed from the air off gas, and the air off gas not containing silicon can be used as the hydrogen sensor 2.
The gas detection chamber 35 of No. 5 enters.

Therefore, the detection element 4 of the hydrogen sensor 25
The catalyst attached to 2 is not poisoned by silicon, and as a result, the hydrogen sensor 25 can be prevented from deterioration and the detection accuracy of the hydrogen sensor 25 can be kept high for a long period of time. . Also in the case of the fourth embodiment, since the silicon trap 90 is provided in the bypass passage 27 located upstream of the installation position of the hydrogen sensor 25, the degree of freedom in designing the silicon trap 90 is increased and the silicon trap 90 is increased. The outer dimensions of 90 and the surface area of the catalyst layer 98 can be freely set, and the silicon removal capability can be increased.

[Other Embodiments] The present invention is not limited to the above-described embodiments. For example, the gas to be detected is not limited to hydrogen gas and may be another gas component, and the gas sensor is not limited to a hydrogen sensor and may be any gas component that detects another gas component. Good. Further, the gas to be inspected is not limited to the cathode off gas discharged from the cathode of the fuel cell. Further, the silicon removing material is only required to be able to remove silicon in the gas to be inspected, and any material can be appropriately used as long as this purpose is achieved. When a catalyst or the like is used as a silicon removing material, it is possible to raise the temperature by energizing or heating to increase the activity of silicon adhesion.

[0039]

As described above, according to the present invention, since the silicon trap is provided upstream of the gas detection chamber, the gas to be inspected whose silicon has been removed by the silicon trap is stored in the gas detection chamber of the gas sensor. As a result, the gas sensor can be prevented from being poisoned with silicon. As a result, it is possible to prevent the deterioration of the gas sensor, and it is possible to maintain the high detection accuracy of the gas sensor for a long period of time. Further, in the present invention, when the silicon removing material is composed of a catalyst,
The silicon contained in the gas to be inspected can be removed by adhering it to the catalyst.

Further, in the present invention, the trap channel is provided with a collision part against which the gas to be inspected collides, and when the silicon removing material is provided in the collision part, it is included in the gas to be inspected. Since the chances of the silicon coming into contact with the silicon removing material are increased and the silicon can be sufficiently removed, there is an effect that the silicon poisoning of the gas sensor can be surely prevented. Further, in the present invention, when the silicon trap is attached to the gas detection chamber so as to cover the gas introduction port for introducing the inspection target gas, the silicon trap can be made compact, and a gas sensor and There is an effect that it can be integrated and is easy to handle.

Further, in the present invention, when the trap channel has a starting end opening for gas introduction and an ending end opening for gas discharge, the gas to be inspected easily flows in the trap channel, This has the effect of improving the detection accuracy of the gas sensor. Further, in the present invention, when the silicon trap is provided in the flow path of the gas to be inspected located upstream of the installation position of the gas sensor,
This has the effect of increasing the degree of freedom in designing the silicon trap and increasing the silicon removal capability.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a gas detection system according to the present invention.

FIG. 2 is a plan view of a hydrogen sensor as a gas sensor used in the first embodiment.

3 is a view showing a mounting state of the hydrogen sensor and the silicon trap, and is a cross-sectional view taken along the line I-I of FIG. 2.

FIG. 4 is a diagram showing a mounting state of a hydrogen sensor and a silicon trap in a second embodiment of a gas detection system according to the present invention.

FIG. 5 is a configuration diagram of main parts in a third embodiment of a gas detection system according to the present invention.

FIG. 6 is a sectional view of a silicon trap used in the third embodiment.

FIG. 7 is a sectional view of a silicon trap used in a fourth embodiment of the gas detection system according to the present invention.

[Explanation of symbols]

22 Air exhaust path (flow path for gas to be inspected) 25 Hydrogen sensor (gas sensor) 27 Bypass path (flow path for gas to be inspected) 35 Gas detection room 37 Gas inlet 42 detector 43 Temperature compensation element 50,80,90 Silicon trap 51 Outer cylinder part (collision part) 53 Flange part (collision part) 55 Intermediate flange part (collision part) 57 Baffle plate (collision part) 60, 68, 85, 96 Trap channel 61, 72, 86, 98 Catalyst layer (silicon removal material) 66 gas inlet (starting end of trap channel) 67 Gas outlet (end of trap channel) 71 Standing wall (collision part) 81a, 81b End plate (collision part) 84a Closed end plate (collision part) 91a, 91b End plate (collision part) 97 Baffle plate (collision part)

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Claims (6)

[Claims] 1. A gas sensor for detecting a gas to be detected by introducing the gas to be inspected into a gas detection chamber provided with a detection element and a temperature compensating element is installed in a flow path of the gas to be inspected, In a gas detection system in which a gas to be detected in a flowing inspection target gas is detected by the gas sensor, a trap passage through which the inspection target gas flows and silicon removal provided on an inner wall surface of the trap passage are provided upstream of the gas detection chamber. A gas detection system comprising a silicon trap having a material. 2. The gas detection system according to claim 1, wherein the silicon removing material is composed of a catalyst. 3. The trap flow path is provided with a collision part against which the gas to be inspected collides, and the silicon removal material is provided in the collision part. Gas detection system. 4. The silicon trap according to claim 1, wherein the silicon trap is attached to the gas detection chamber so as to cover a gas inlet for introducing the gas to be inspected. Gas detection system. 5. The gas detection system according to claim 4, wherein the trap channel has a starting end that opens for gas introduction and an ending end that opens for gas discharge. 6. The silicon trap according to claim 1, wherein the silicon trap is provided in a flow path of the gas to be inspected, which is located upstream of a position where the gas sensor is installed. Gas detection system.