Vehicle tail gas probe type detection device and detection method
By employing a cylindrical thin tube and guide bushing structure in the vehicle exhaust gas probe, combined with a thermal separation mechanism to control the opening and closing of the air inlet, the problem of probe blockage was solved, enabling smooth exhaust gas detection and efficient gas collection.
Patent Information
- Application Number
- CN202511022724.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-24
- Publication Date
- 2025-11-07
AI Technical Summary
Existing vehicle exhaust gas sensors are prone to carbon buildup and blockage during testing, leading to airflow obstruction.
Design a vehicle exhaust gas probe-type detection device, which adopts a hollow tubular cylindrical thin tube and guide bushing structure. The opening and closing of the air inlet is controlled by a thermal separation mechanism to ensure that carbon deposits are prevented from entering when the probe is inserted into the exhaust pipe. When the probe temperature rises, the air inlet is automatically opened to collect exhaust gas.
This effectively avoids the problem of probe clogging during repeated use, ensuring smooth exhaust gas detection and unobstructed gas sampling channels.
Smart Images
Figure CN120907913A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of exhaust gas detection plug-in probe, in particular to a vehicle exhaust probe type detection device and detection method. BACKGROUND
[0002] Currently, there are two ways for vehicle exhaust detection, one is to realize real-time dynamic detection of the exhaust of passing vehicles on the road surface through a remote sensing monitoring system, and the other is to conduct static detection of the exhaust of vehicles at an annual inspection station during annual inspection. The exhaust detection at the annual inspection station mainly uses a waste gas analyzer (mainly a five-component analyzer).
[0003] As a front probe of the waste gas analyzer, the probe needs to be inserted into the exhaust pipe during the detection process to collect gas samples. Therefore, the front end of the commonly used probe is an open circular tube. The gas enters the probe from the open end of the front end and is then sucked into the sampling tube by the active suction of the five-component analyzer. However, in the process of entering some exhaust pipes with a large amount of carbon deposition, the open end design of the probe and the overall diameter of the probe, which is generally about 10 mm, result in that the thin-walled pipe at the front end of the circular tube will inevitably scrape off the carbon deposition on the wall of the exhaust pipe and enter the sampling tube.
[0004] Although a filter screen is provided on the connecting hose directly connected with the probe to block the carbon deposition, the gas path will still be blocked after a long time. SUMMARY
[0005] The present application aims to provide a vehicle exhaust probe type detection device and detection method to solve the problem of easy blockage of the gas sampling probe.
[0006] To solve the above technical problems, the present application specifically provides the following technical solutions:
[0007] A vehicle exhaust probe type detection device, comprising a gas analyzer, a probe, and a hose connecting the two, wherein the probe is used to collect exhaust gas,
[0008] The probe at least comprises a cylindrical thin tube in a hollow tubular shape and a guide bushing in a hollow tubular shape. One end of the cylindrical thin tube is open, and the other end is closed. An air inlet hole is provided in the side wall of the cylindrical thin tube. The cylindrical thin tube is in internal communication with the guide bushing to form a gas sampling channel, and the gas sampling channel is in communication with the hose.
[0009] The open end of the cylindrical thin tube is inserted into one end of the guide bushing, and the cylindrical thin tube can move axially in the guide bushing under the action of an external force. The air inlet hole is closed when the cylindrical thin tube completely enters the guide bushing, and is exposed when the cylindrical thin tube partially extends out of the guide bushing.
[0010] Further, a first force applying device is arranged between the insertion end of the cylindrical thin tube and the inner end of the guide bushing to apply a first force to the cylindrical thin tube, and a second force applying device is arranged between the outer wall of the guide bushing and the outside of the closed end of the cylindrical thin tube to apply a second force to the cylindrical thin tube, the first force and the second force are opposite, and the cylindrical thin tube can be moved by reducing or increasing the second force.
[0011] Further, the second force applying device is arranged as a heat-sensitive separation mechanism that reduces or increases the second force when heated to a preset temperature.
[0012] Further, the heat-sensitive separation mechanism is a memory alloy spring, and the first force applying device is a tension spring.
[0013] The phase transition temperature of the memory alloy spring is set as the preset temperature.
[0014] The material elasticity of the memory alloy spring after phase transition is greater than the tension of the tension spring.
[0015] Further, the heat-sensitive separation mechanism is two annular magnets arranged outside the cylindrical thin tube and the guide bushing respectively, and the first force applying device is a conventional spring.
[0016] The demagnetization temperature of the annular magnet is set as the preset temperature.
[0017] The magnetic attraction of the two annular magnets in a normal state is greater than the elasticity of the conventional spring.
[0018] Further, the insertion end of the probe is fixedly sleeved with a metal bushing in a hollow tubular shape, the metal bushing is fixedly connected with the pipe wall of the probe end portion through a certain pin, a sliding bushing is sleeved outside the metal bushing, the sliding bushing is fixedly connected with the cylindrical thin tube through a moving pin, a sliding groove hole for moving the moving pin along the axial direction of the guide bushing is formed in the side wall of the guide bushing, and the two ends of the first force applying device act on the fixed pin and the moving pin respectively.
[0019] Further, a first mounting groove for positioning and mounting one end of the second force applying device is formed on the outside of the guide bushing, and a second mounting groove for positioning and mounting the other end of the second force applying device is formed on the outside of the sliding bushing.
[0020] Further, a positioning steel wire cage is detachably fixedly connected to the outside of the front end of the probe, and the outer diameter of the positioning steel wire cage is 30 mm.
[0021] A detection method of a vehicle exhaust probe type detection device, the detection method comprising the following steps:
[0022] S1, inserting the probe into the exhaust pipe of a vehicle, during the insertion process, the environment temperature of the heat sensitive separation mechanism does not reach the preset temperature for opening the gas sampling channel, at this time, the cylindrical thin tube does not move axially, thus the gas inlet hole is in a closed state to prevent the carbon deposition or foreign matter on the exhaust pipe wall from entering the probe;
[0023] S2, after the probe is in place in the exhaust pipe, waiting for the temperature of the exhaust gas in the exhaust pipe to rise, when the environment temperature of the probe reaches the preset temperature, the heat sensitive separation mechanism moves to make the cylindrical thin tube displace along the axial direction of the probe, thus the cylindrical thin tube partially extends out of the guide bushing, allowing the exhaust gas to enter the gas sampling channel in the probe from the exposed gas inlet hole;
[0024] S3, the gas analyzer collects the exhaust gas sample from the opened gas inlet hole by active gas sampling, and detects the composition of the exhaust gas sample;
[0025] S4, after the detection is completed, the probe is taken out of the exhaust pipe;
[0026] S5, the probe is placed on a heat dissipation support for cooling the probe.
[0027] Further, in step S5, if the heat sensitive separation mechanism is a ring-shaped magnet, the heat sensitive magnet is magnetized on the heat dissipation support by an integrated magnetizer to restore the magnetism.
[0028] Advantages of the present application:
[0029] The present application avoids the carbon deposition or foreign matter from entering the gas sampling channel by keeping the gas inlet hole of the cylindrical thin tube retracted into the guide bushing during the insertion of the probe into the exhaust pipe, and the cylindrical thin tube is moved forward to extend out to expose the gas inlet hole for the exhaust gas to enter the detection by external force when the exhaust gas needs to be collected, thus effectively avoiding the blockage of the probe during repeated use. BRIEF DESCRIPTION OF DRAWINGS
[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.
[0031] Figure 1 It is a schematic diagram of the three-dimensional structure of the probe of the present application;
[0032] Figure 2 Fig. 1 is a schematic diagram of the use state of the probe of the present application;
[0033] Figure 3 Fig. 2 is a schematic diagram of the working state of the probe of the present application Figure 1 ;
[0034] Figure 4 Fig. 3 is a schematic diagram of the working state of the probe of the present application Figure 2 ;
[0035] Figure 5 Fig. 4 is a schematic diagram of the exploded structure of the probe of the present application;
[0036] Figure 6 Fig. 5 is a schematic diagram of the structure at A in Fig. 4; Figure 3
[0037] Figure 7 Fig. 6 is a schematic diagram of the gas collecting state in the working state of the probe of the present application;
[0038] Figure 8 Fig. 7 is a schematic diagram of the working state of another specific embodiment of the present application Figure 1 ;
[0039] Figure 9 Fig. 8 is a schematic diagram of the working state of another specific embodiment of the present application Figure 2 ;
[0040] The reference numerals in the figures represent the following respectively: 1-probe; 2-metal bushing; 3-guiding bushing; 4-sliding bushing; 5-plug; 6-cylindrical thin tube; 7-moving pin; 8-slotted hole; 9-gas inlet hole; 10-positioning steel wire cage; 11-first mounting slot; 12-second mounting slot; 13-ring magnet; 14-regular spring; 15-memory alloy spring; 16-steel wire traction ring; 17-elastic sheet protrusion; 18-exhaust pipe; 19-fixing pin; 20-tension spring. DETAILED DESCRIPTION
[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application.
[0042] Reference Figures 1 to 9 As shown, a vehicle exhaust probe type detection device includes a gas analyzer, a probe 1 for collecting exhaust gas, and a hose connecting the two, the probe 1 at least including a hollow tubular cylindrical thin tube 6 with one end open and the other end closed, and a hollow tubular guide bushing 3, a gas inlet hole 9 being provided through the side wall of the cylindrical thin tube 6, the cylindrical thin tube 6 being in communication with the guide bushing 3 to form a gas collection channel, and the gas collection channel being in communication with the hose;
[0043] The open end of the cylindrical thin tube 6 is inserted into one end of the guide bushing 3, and the cylindrical thin tube 6 can move axially in the guide bushing 3 under the action of an external force, the gas inlet hole 9 being closed when the cylindrical thin tube 6 is fully inserted into the guide bushing 3, and being exposed when the cylindrical thin tube 6 partially extends out of the guide bushing 3. The front end of the cylindrical thin tube 6 is further provided with a flow guide shaped plug 5 for reducing the frictional resistance between the probe 1 and the exhaust pipe 18 during forward movement, and the exhaust gas flows from the gas inlet hole 9 to the gas collection channel after being guided by the plug 5, and then enters the gas analyzer.
[0044] The embodiment mainly provides the gas inlet hole (9) for collecting exhaust gas in a manner that the opening and closing state can be controlled, preferably in a closed state initially, and then opened by an external force after entering the collection environment (such as a vehicle exhaust pipe), to avoid collecting non-target gas before the detection device detects, and to avoid foreign matter from entering.
[0045] For the embodiment, any driving mode that allows the cylindrical thin tube (6) and the guide bushing (3) to move relative to each other is not limited, and the following is an implementation principle for allowing the cylindrical thin tube (6) and the guide bushing (3) to move relative to each other: a first force applying device is provided between the insertion end of the cylindrical thin tube 6 and the inner end of the guide bushing 3 to apply a first force to the cylindrical thin tube 6, a second force applying device is provided between the outer wall of the guide bushing 3 and the outside of the closed end of the cylindrical thin tube 6 to apply a second force to the cylindrical thin tube 6, the first force and the second force are opposite, and the cylindrical thin tube 6 can be moved by reducing or increasing the second force.
[0046] The following provides three preferred embodiments:
[0047] First embodiment:
[0048] The second force applying device is provided as a heat sensitive separation mechanism that reduces the second force until it disappears when heated to a preset temperature. The heat sensitive separation mechanism is two annular magnets 13 provided outside the cylindrical thin tube 6 and the guide bushing 3, and the first force applying device is a conventional spring 14;
[0049] The demagnetization temperature of the annular magnet 13 is set as the preset temperature, for suddenly reducing the magnetic force of the annular magnet 13 until it disappears when the environment reaches the required temperature for gas collection, thereby opening the gas collection channel;
[0050] The magnetic attraction of the two annular magnets 13 is greater than the elastic force of the conventional spring 14 in normal state, so as to ensure that the probe 1 keeps the gas inlet passage closed during the insertion process.
[0051] During the insertion of the probe 1 into the exhaust pipe 18, the plug 5 is fixed by magnetic attraction because the magnetic attraction between the two annular magnets 13 is greater than the elastic force of the conventional spring 14 at normal temperature, so as to close the gas inlet hole 9 and prevent the carbon deposition from entering; when the temperature of the front end of the probe 1 rises to the Curie temperature of the annular magnet 13, the magnetic attraction of the magnet suddenly decreases, at this time, the elastic force of the conventional spring 14 pushes the plug 5 to move forward, exposing the gas inlet hole 9 to start gas sampling; after the probe 1 is taken out and cooled, the magnetic attraction of the annular magnet 13 is restored, the sliding bushing 4 is adsorbed again, the conventional spring 14 is compressed, and the gas inlet hole 9 is closed, thereby realizing the function of automatically controlling the opening and closing of the plug 5 by temperature change.
[0052] However, in this embodiment, the annular magnet 13 may adsorb metal debris and other impurities outside the probe 1 during the insertion and extraction of the probe 1 into the exhaust pipe 18, and therefore the present application further provides another embodiment as follows.
[0053] Second embodiment:
[0054] Referring to Figure 8 and Figure 9 , the second force applying device is a heat-sensitive separation mechanism which increases the second force when heated to a preset temperature. The heat-sensitive separation mechanism is a memory alloy spring 15, and the first force applying device is a tension spring 20;
[0055] In the above two embodiments based on the heat-sensitive principle, the starting temperature range of the heat-sensitive separation mechanism is selected according to the actual working condition. The temperature of the tail section of the exhaust pipe is usually significantly lower than that of the head section of the exhaust pipe because the tail section is far away from the heat source of the engine and is cooled by the pipeline. The actual measurement data shows that:
[0056] When cold-starting or idling, the temperature of the tail section is about 60-100℃;
[0057] When driving at medium-low speed, the temperature of the tail section can rise to 80-120℃;
[0058] When driving at high speed, the temperature of the tail section is about 140-160℃ at most (but the duration is relatively short).
[0059]
[0060] Therefore, the selection of the preset temperature range needs to ensure that the heat-sensitive separation mechanism triggers in the common temperature range (80-120℃) of the tail section, while avoiding false opening in the low-temperature stage (insertion).
[0061] The lower limit temperature (80℃) is based on the fact that it is higher than the ambient temperature (up to about 50℃) and the temperature rise caused by the contact with the exhaust pipe 18 during insertion (usually <70℃), to avoid false opening of the plug at room temperature or during insertion;
[0062] The upper limit temperature (120℃) is based on the fact that it is lower than the short-term peak temperature (140℃+) of the exhaust tail section under high-speed working conditions, with a 20℃ safety redundancy to prevent performance degradation of the material due to long-term proximity to the upper limit temperature; and to ensure that the tail section temperature reaches 100-120℃ to reliably trigger under medium and low-speed working conditions (accounting for more than 80% of daily detection scenarios).
[0063] For both of the above two embodiments, a heat dissipation bracket is also provided for heat dissipation, and a fan provided on the heat dissipation bracket can accelerate the cooling of the memory alloy spring 15 or the annular magnet 13, and a magnetizer integrated on the bracket can magnetize the annular magnet 13 to restore its magnetism, make up for the magnetic decay caused by high temperature, and ensure reliable triggering in the next use.
[0064] As the most basic embodiment of the present application, the following is provided:
[0065] Third embodiment:
[0066] A steel wire rope is fixed to the closed end of the cylindrical thin tube 6 (i.e. the end extending out of the guide bushing 3) and is held in the hand of an operator outside the exhaust pipe 18, and a return spring is provided between the cylindrical thin tube 6 and the guide bushing 3, so that during the insertion of the probe, the operator holds the steel wire rope to keep the cylindrical thin tube 6 in a state of being retracted into the guide bushing 3 (i.e. the sampling airway is closed), and releases the steel wire rope during detection, so that the cylindrical thin tube is extended out of the guide bushing 3 under the action of the return spring, thereby opening the sampling airway.
[0067] In the above three embodiments, in order to ensure that the cylindrical thin tube 6 can be stably positioned inside the front end of the probe 1 for axial movement, preferably, a metal bushing 2 is fixed at the front end of the probe 1, the metal bushing 2 is fixedly connected with the probe 1 through a certain pin 19, the outside of the metal bushing 2 is sleeved with a sliding bushing 4, the sliding bushing 4 is fixedly connected with the cylindrical thin tube 6 through a dynamic pin 7, and a sliding slot hole 8 for moving the dynamic pin 7 along the axial direction of the guide bushing 3 is formed in the side wall of the guide bushing 3, to provide a movement basis for the subsequent axial displacement of the sliding bushing 4; in different embodiments, the fixed pin 19 and the dynamic pin 7 are respectively used for connecting or abutting the two ends of the tension spring 20, the conventional spring 15, or the return spring.
[0068] In the first and second embodiments, in order to ensure that the memory alloy spring 15 or the ring magnet 13 can better contact the high-temperature exhaust gas, the memory alloy spring 15 or the ring magnet 13 is arranged on the outer side of the probe 1, so that it can sufficiently contact the heat source to ensure that it can work normally. In order to stably install the memory alloy spring 15 or the ring magnet 13, a first installation groove 11 for positioning and installing one end of the memory alloy spring 15 or one of the ring magnets 13 is formed on the outer side of the lower end of the guide bushing 3, and a second installation groove 12 for positioning and installing the other end of the memory alloy spring 15 or the other ring magnet 13 is formed on the lower end of the sliding bushing 4. This structure realizes that the two forms of the memory alloy spring 15 and the ring magnet 13 do not need to change the main structure of the front end of the probe 1. For the two different forms, the two ends of the tension spring 20 or the two ends of the conventional spring 14 act on the fixed pin 19 and the moving pin 7, respectively. The tension spring 20 is tensioned at both ends of the fixed pin 19 and the moving pin 7, and the conventional spring 14 is abutted at both ends of the fixed pin 19 and the moving pin 7.
[0069] In the above three embodiments, in order to further ensure that the probe 1 can have higher sampling efficiency, a positioning steel wire cage 10 is detachably fixedly connected to the outer side of the front end of the probe 1. Since the outer diameter of the probe itself is about 10 mm, and the inner diameter of the exhaust pipe of a household vehicle is generally between 38 mm and 60 mm, and the pipe diameter of some high-performance vehicles can reach 75 mm, there is a large diameter difference between the probe and the exhaust pipe, which makes it difficult for the probe to maintain coaxial with the exhaust pipe (when the angle between the two axes is small, the sampling efficiency is highest). The front end of the probe can be inclined to contact the inner wall of the exhaust pipe during the sampling process, which reduces the effective cross-sectional area of the inlet in the direction of the airflow, thereby affecting the sampling efficiency. Therefore, the probe 1 of the present embodiment can be kept in the center position in the exhaust pipe 18 under the limiting action of the positioning steel wire cage 10, so as to overcome the above problems. The size of the positioning steel wire cage 10 can also be flexibly replaced according to the diameter of the exhaust pipe of the target vehicle.
[0070] The following is the disassembly and replacement method and principle of the positioning wire cage 10: both ends of the positioning wire cage 10 are provided with steel wire traction rings 16 that can be slidably sleeved on the outer side of the metal bushing 2, and the side wall of the metal bushing 2 is formed with a plurality of elastic sheet protrusions 17 uniformly distributed in the circumferential direction for the steel wire traction rod to be extruded through. The elastic sheet protrusions 17 are made of elastic material and are uniformly distributed in the circumferential direction of the metal bushing 2, and in the initial state, they protrude radially outward and form a limiting fit with the inner wall of the steel wire traction ring 16. When a larger size positioning wire cage 10 needs to be replaced, the handle end of the probe 1 is separated from the hose, and the existing positioning wire cage 10 is pulled out axially with force. At this time, the end face of the steel wire traction ring 16 will extrude the elastic sheet protrusion 17, forcing the elastic sheet to contract radially, thereby releasing the limiting constraint of the steel wire traction ring 16, so that the steel wire traction ring 16 can be smoothly withdrawn from the metal bushing 2; when installing a new positioning wire cage 10, align the steel wire traction ring 16 with the metal bushing 2 and push it axially with force. The chamfered surface of the steel wire traction ring 16 will again extrude the elastic sheet protrusion 17 to make it contract radially. After the steel wire traction ring 16 passes over the elastic sheet protrusion 17, the elastic sheet will reset due to its own elasticity and reengage with the inner wall of the steel wire traction ring 16, completing the fixation of the positioning wire cage 10. This structural design allows the replacement of the positioning wire cage 10 to be completed manually without the need for tools. The elastic deformation of the elastic sheet protrusion 17 enables quick disassembly and assembly, significantly improving the convenience of equipment maintenance, while ensuring that positioning wire cages 10 of different sizes can be flexibly replaced according to the inner diameter of the exhaust pipe 18, enhancing the adaptability of the device to various detection scenarios.
[0071] Since the inner diameter of the exhaust pipe of a household vehicle is generally between 38mm and 60mm, and the pipe diameter of some high-performance vehicles can reach 75mm, the outer diameter of the positioning wire cage 10 is preferably 30mm. An outer diameter of 30mm can ensure that the wire cage is smoothly inserted into the exhaust pipe 18 of different vehicle models, adapts to different pipe diameters, realizes "one cage for all", and reduces equipment costs. This size ensures that the probe 1 is within the central region of the exhaust pipe 18, ensuring high intake efficiency of the probe 1.
[0072] The following is a method for detecting exhaust gas using the detection device, comprising the following steps:
[0073] S1, insert the probe 1 into the exhaust pipe 18 of the vehicle. During insertion, the environment temperature of the heat-sensitive separation mechanism does not reach the lower limit of the opening temperature of the plug 5, so that the front end of the plug 5 closes the air inlet hole 9, preventing carbon or foreign matter on the wall of the exhaust pipe 18 from being scraped off and entering the probe 1;
[0074] S2, after the probe 1 is in place in the exhaust pipe 18, waiting for the exhaust gas temperature in the exhaust pipe 18 to rise, when the temperature at the front end of the probe 1 reaches the temperature at which the plug 5 is opened, the heat-sensitive separation mechanism is activated to displace the plug 5 in the axial direction of the probe 1, thereby opening the plug 5 to open the gas sampling channel and allowing the exhaust gas to enter the probe 1;
[0075] S3, the gas analyzer collects the exhaust gas sample from the opened gas inlet hole 9 by actively pumping, and detects the composition of the exhaust gas sample;
[0076] S4, after the detection is completed, the probe 1 is removed from the exhaust pipe 18;
[0077] S5, the probe 1 is placed on a heat dissipation support for cooling the probe 1.
[0078] Further, in step S5, if the heat-sensitive separation mechanism is the annular magnet 13, the heat-sensitive magnet is magnetized on the heat dissipation support by an integrated magnetizer to restore its magnetic properties, compensate for the magnetic decay caused by high temperature, and ensure that the heat-sensitive separation mechanism can work normally next time.
[0079] The above embodiments are only exemplary embodiments of the present application and are not intended to limit the present application. The scope of protection of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and scope of the present application, and such modifications or equivalent replacements are also considered to fall within the scope of protection of the embodiments of the present application.
Claims
1. A vehicle exhaust probe type detection device, comprising a gas analyzer, a probe (1) for collecting exhaust gas and a hose connecting the two, characterized in that: the probe (1) comprises at least a hollow tubular cylindrical thin tube (6) with one open end and one closed end, and a hollow tubular guide bushing (3), the cylindrical thin tube (6) has an air inlet hole (9) in the side wall, the cylindrical thin tube (6) and the guide bushing (3) are in communication to form an air collection channel, and the air collection channel is in communication with the hose; the open end of the cylindrical thin tube (6) is inserted into one end of the guide bushing (3), and the cylindrical thin tube (6) can move axially in the guide bushing (3) under the action of external force, the air inlet hole (9) is closed when the cylindrical thin tube (6) is fully inserted into the guide bushing (3), and is exposed when the cylindrical thin tube (6) partially extends out of the guide bushing (3).
2. The vehicle exhaust probe type detection device according to claim 1, characterized in that: a first force applying device is arranged between the inserted end of the cylindrical thin tube (6) and the inner end of the guide bushing (3) to apply a first force to the cylindrical thin tube (6), and a second force applying device is arranged between the outer wall of the guide bushing (3) and the outside of the closed end of the cylindrical thin tube (6) to apply a second force to the cylindrical thin tube (6), the first force and the second force are opposite, and the cylindrical thin tube (6) can be moved by reducing or increasing the second force.
3. The vehicle exhaust probe type detection device according to claim 2, characterized in that: the second force applying device is a heat sensitive separation mechanism that reduces or increases the second force when heated to a preset temperature.
4. The vehicle exhaust probe type detection device according to claim 3, characterized in that: the heat sensitive separation mechanism is a memory alloy spring (15), and the first force applying device is a tension spring (20); wherein the phase transition temperature of the memory alloy spring (15) is set as the preset temperature; the material elasticity of the memory alloy spring (15) after phase transition is greater than the tension of the tension spring (20).
5. The vehicle exhaust probe type detection device according to claim 3, characterized in that: the heat sensitive separation mechanism is two annular magnets (13) arranged outside the cylindrical thin tube (6) and the guide bushing (3) respectively, and the first force applying device is a conventional spring (14); wherein the demagnetization temperature of the annular magnet (13) is set as the preset temperature; the magnetic attraction of the two annular magnets (13) in normal state is greater than the elasticity of the conventional spring (14).
6. The vehicle exhaust probe type detection device according to claim 2, characterized in that: The extending end of the probe (1) is fixedly sleeved with a hollow tubular metal bushing (2) which is fixedly connected with the pipe wall of the end of the probe (1) through a pin (19), a sliding bushing (4) is sleeved on the outside of the metal bushing (2), the sliding bushing (4) is fixedly connected with the cylindrical thin pipe (6) through a moving pin (7), a sliding slot hole (8) for moving the moving pin (7) along the axial direction of the guide bushing (3) is formed on the side wall of the guide bushing (3), and the two ends of the first force applying device act on the fixed pin (19) and the moving pin (7) respectively.
7. The vehicle exhaust probe type detection device according to claim 6, characterized in that, A first mounting slot (11) for positioning and mounting one end of the second force applying device is formed on the outside of the guide bushing (3), and a second mounting slot (12) for positioning and mounting the other end of the second force applying device is formed on the outside of the sliding bushing (4).
8. The vehicle exhaust probe type detection device according to claim 1, wherein A positioning steel wire cage (10) is detachably fixedly connected to the outside of the front end of the probe (1), and the outer diameter of the positioning steel wire cage is 30 mm.
9. The method of claim 4 or 5, wherein the method further comprises: The detection method comprises the following steps: S1, the probe (1) is inserted into the exhaust pipe (18) of the vehicle, during the insertion process, the ambient temperature of the heat sensitive separation mechanism does not reach the preset temperature for opening the gas sampling channel, at this time, the cylindrical thin pipe (6) does not move axially, and therefore the gas inlet hole (9) is in a closed state to prevent the carbon deposition or foreign matter on the wall of the exhaust pipe (18) from entering the probe (1); S2, after the probe (1) is positioned in the exhaust pipe (18), the exhaust gas temperature in the exhaust pipe (18) is raised, when the ambient temperature of the probe (1) reaches the preset temperature, the heat sensitive separation mechanism moves to make the cylindrical thin pipe (6) displace along the axial direction of the probe (1), so that the cylindrical thin pipe (6) partially extends out of the guide bushing (3), and the exhaust gas is allowed to enter the gas sampling channel in the probe (1) from the exposed gas inlet hole (9); S3, the gas analyzer collects the exhaust gas sample from the opened gas inlet hole (9) by actively pumping the gas, and detects the composition of the exhaust gas sample; S4, after the detection is completed, the probe (1) is taken out of the exhaust pipe (18); S5, the probe (1) is placed on a heat dissipation support for cooling the probe (1) to cool down.
10. The method of claim 9, wherein the method further comprises: In step S5, if the heat sensitive separation mechanism is a ring-shaped magnet, the heat sensitive magnet is magnetized on the heat dissipation support through an integrated magnetizer to restore the magnetism.