An EGR differential pressure sensor

Abstract

The present invention relates to the technical field of pressure sensors, and discloses an EGR differential pressure sensor, wherein the detection unit comprises a detection core and a drainage pipe, wherein the detection core comprises a sintered seat with a pressure detection element disposed therein and a metal pressure diaphragm disposed at both ends of the sintered seat; the drainage pipe is connected to both ends of the detection core and communicated with a pressure test pipe port, and is used to drain the measured gas from the pressure test pipe port to the detection core, so that particulate pollutants such as carbon deposits are kept away from the detection core. The EGR differential pressure sensor, by adding a drainage pipe with a guiding and drainage function to the detection core, separates the measured gas from the pressure detection element of the sensor, and only contacts the metal pressure diaphragm of the detection core. The guidance of the drainage pipe has a buffering effect on the measured gas with a large impact force, and at the same time, the carbon deposit particles are attached to the inner wall of the drainage pipe, so that the carbon deposits are separated from the detection core to avoid corrosion.

Description

Technical Field

[0001] The invention relates to the technical field of pressure sensors, in particular to an EGR pressure difference sensor. Background Art

[0002] The EGR differential pressure sensor is a sensor used to measure the difference between two pressures. It is usually used to measure the pressure difference between the front and rear ends of a device or component. The most typical application is the exhaust gas pressure difference used in the Exhaust Gas Recirculation system.

[0003] In the prior art, the exhaust gas and carbon deposits in the vehicle exhaust gas recirculation system, such as carbon monoxide CO, hydrocarbons HC, nitrogen oxides NOx, sulfides and PM (particulate matter is composed of carbon smoke, heavy metal oxides such as lead oxides and soot, oil vapor, etc.), have high exhaust gas temperature and fast carbon deposition speed. The residual high-temperature exhaust gas and fast-depositing carbon particles in the exhaust gas circuit will damage the piezoresistive detection element. At the same time, nitrogen oxides form an acidic solution when they meet water vapor, which is easy to corrode the piezoresistive detection element and circuit of the sensor. Therefore, it is best to isolate the sensor detection piezoresistive detection element from pollutants. At the same time, the exhaust gas pressure in the exhaust gas circuit is relatively small and the operating environment is harsh. It is necessary to use a corrosion-resistant, high-temperature resistant and accurate pressure measurement unit to accurately sense the pipeline pressure and protect the pressure detection unit. Therefore, an EGR differential pressure sensor is proposed to solve the above-mentioned problems. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the shortcomings of the prior art, the present invention provides an EGR differential pressure sensor, which has the advantages of withstanding large pressure shocks and high-speed carbon deposition, etc., and solves the problem that when the EGR differential pressure sensor in the prior art is in use, the residual high-temperature exhaust gas and fast-deposited carbon particles in the exhaust gas circuit may damage the piezoresistive detection element, and at the same time, nitrogen oxides form an acidic solution when meeting water vapor, which is easy to corrode the piezoresistive detection element and circuit of the sensor.

[0006] (II) Technical solution

[0007] In order to achieve the above-mentioned purpose of withstanding large pressure shocks and high-speed carbon deposition, the present invention provides the following technical solutions: an EGR differential pressure sensor, comprising an outer shell and an upper cover thereon, wherein a detection unit is provided in the outer shell, and an electrical connector electrically connected to the detection unit is provided on the upper cover; two pressure test pipe openings are also provided in the outer shell for introducing the gas to be tested into the detection unit, wherein the detection unit comprises a detection core and a drainage pipe, wherein the drainage pipe is connected at both ends of the detection core, and the drainage pipe is also connected to the pressure test pipe opening, and the drainage pipe is used to guide the detection gas drained from the pressure test pipe opening to the detection core.

[0008] Preferably, the detection core is vertically arranged inside the housing via a first clip plate.

[0009] Preferably, the drainage pipeline includes a short drainage tube and a long drainage tube, the short drainage tube is coaxially and sealably connected to the lower end of the vertically arranged detection core; the long drainage tube is sealably connected to the upper end of the vertically arranged detection core.

[0010] Preferably, the long drainage tube is used to guide and drain the measured gas introduced into the pressure test tube orifice 180 degrees; the long drainage tube includes a first connecting tube, and the two ends of the first connecting tube are respectively connected to a first sealing connector and a second sealing connector, the first sealing connector and the second sealing connector are vertically arranged at the two ends of the first connecting tube, and the openings are both facing downward; the opening of the first sealing connector is sealed and connected to the upper end of the vertically arranged detection core; the opening of the second sealing connector is connected to the pressure test tube orifice.

[0011] Preferably, a third sealing joint is provided in the pressure test pipe opening in the housing that is connected to the second sealing joint, and the third sealing joint is sealingly connected to the second sealing joint.

[0012] Preferably, a fixing buckle is also connected to the first spring plate, and the fixing buckle is used to reinforce the connection between the long drainage tube and the vertically arranged detection core.

[0013] Preferably, the detection core is horizontally arranged inside the housing via a second clip plate.

[0014] Preferably, the drainage pipes are two identical drainage pipes, and are symmetrically sealed and connected at two ends of a horizontally arranged detection core.

[0015] Preferably, the drainage pipe is used to guide and drain the measured gas introduced into the pressure test pipe mouth at a 180-degree angle; the drainage pipe includes a second connecting pipe arranged vertically; the upper end of the second connecting pipe is closed, and the lower end is open; a third sealing connector is coaxially connected to the opening of the second connecting pipe, and the third sealing connector is connected to the pressure test pipe mouth; a fourth sealing joint is connected to the pipe wall of the closed end of the second connecting pipe; the second connecting pipe is arranged horizontally, and is sealed and connected to both ends of the horizontally arranged detection core.

[0016] Preferably, the detection core comprises a sintered seat with a pressure detection element disposed therein and metal pressure diaphragms disposed at both ends of the sintered seat.

[0017] (III) Beneficial effects

[0018] Compared with the prior art, the present invention provides an EGR pressure difference sensor, which has the following beneficial effects:

[0019] 1. The EGR differential pressure sensor separates the measured gas from other components of the sensor by adding a drainage pipe with a guiding and drainage function to the detection core, and only contacts the detection part of the detection core to reduce corrosion; the guidance of the drainage pipe has a buffering effect on the measured gas with a large impact force, and at the same time makes the carbon deposit particles adhere to the inner wall of the drainage pipe, separating the carbon deposit and the detection core to avoid corrosion. In addition, due to the guidance of the drainage pipe, nitrogen oxides form an acidic solution when they meet water vapor and are difficult to contact the detection core, thereby avoiding corrosion, withstanding the influence of high-speed carbon deposition, improving service life and measurement accuracy, and increasing durability.

[0020] 2. The EGR differential pressure sensor has a metal pressure diaphragm disposed on the detection core, so that the metal pressure diaphragm contacts the measured gas to avoid corrosion and is also impact-resistant.

[0021] 3. The EGR differential pressure sensor has a simple connection method between the horizontally or vertically arranged detection core, the housing and the flexible plate, which is convenient for production and processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the first embodiment of the present invention;

[0023] Figure 2 This is a schematic structural diagram of a detection unit and a housing in the first embodiment of the present invention.

[0024] Figure 3 This is a schematic structural diagram of a housing in the first embodiment of the present invention;

[0025] Figure 4 A schematic diagram of the structure of the detection unit in the first embodiment of the present invention

[0026] Figure 5 This is a schematic structural diagram of a detection core and a long drainage tube in a first embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the structure of the drainage long tube in the first embodiment of the present invention

[0028] Figure 7 It is a schematic diagram of the overall structure of the second embodiment of the present invention;

[0029] Figure 8 A schematic diagram of the structure of the detection unit and the housing in the second embodiment of the present invention

[0030] Fig. 9A schematic structural diagram of a detection unit in a second embodiment of the present invention;

[0031] Fig.10 A schematic diagram of the structure of the detection unit in the second embodiment of the present invention

[0032] In the figure: 1 housing, 2 upper cover, 3 electrical connector, 4 first detection unit, 41 first spring plate, 42 detection core in vertical state, 43 fixing buckle, 44 long drainage tube, 441 first connecting tube, 442 first sealing connector, 443 second sealing connector, 45 first flexible plate, 46 short drainage tube, 47 metal pressure diaphragm, 5 second detection unit, 51 second spring plate, 52 drainage pipe, 521 second connecting tube, 522 third sealing connector, 523 fourth sealing connector, 53 detection core in horizontal state, 54 second flexible plate. DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] An EGR pressure difference sensor includes a shell 1 and an upper cover 2 covering the upper cover. A detection unit is arranged inside the shell 1. The upper cover 2 is provided with an electrical connector 3 electrically connected to the detection unit. Two pressure test pipe openings for introducing the gas to be tested into the detection unit are arranged inside the shell 1. The detection unit includes a detection core and a drainage pipe. The detection core includes a sintered seat with a pressure detection element arranged inside and a metal pressure diaphragm arranged at both ends of the sintered seat. A pressure transmission medium is encapsulated inside the sintered seat. The pressure detection element can be a piezoresistive detection element. The pressure transmission medium can be silicone oil. The shape of the sintered seat can be cylindrical. The metal pressure diaphragm The sintering seat is sealed and fixedly connected, and the pressure detection medium is sealed inside the sintering seat. When the pressure of the gas to be measured acts on the metal pressure diaphragm, the pressure is sent to the pressure detection element through the pressure transmission medium for detection; the drainage pipe is connected to the two ends of the detection core body and is connected to the pressure test pipe mouth, which is used to guide the gas to be measured from the pressure test pipe mouth to the detection core body for pressure detection, and to keep the carbon deposits generated at high speed away from the detection core body to avoid corrosion; the gas to be measured by the detection core body and the drainage pipe is the exhaust gas and carbon deposits in the vehicle exhaust gas recirculation system. Please refer to the following two embodiments for the specific structure of the detection core body and the drainage pipe;

[0035] Embodiment 1

[0036] like Figure 1-Figure 6The detection core in the first detection unit 4 is shown to be in a vertically arranged state and has a corresponding drainage pipe structure;

[0037] The metal pressure diaphragm 47 on the vertical detection core 42 protects the vertical detection core. The vertical detection core 42 is fixedly installed on the shell 1 through the first retaining spring plate 41, and the first retaining spring plate 41 is adapted to the shell 1; the drainage pipeline is composed of a drainage short tube 46 and a drainage long tube 44, the drainage short tube 46 is coaxially sealed and connected to the lower end of the vertical detection core 42, and is connected to one of the pressure test pipe openings 101 in the shell 1; the drainage long tube 44 is sealed and connected to the upper end of the vertical detection core 42, and is connected to another pressure test pipe opening 102 in the shell 1, so as to introduce the measured gas into the vertical detection core 42; a fixing buckle 43 is also connected to the first retaining spring plate 41, and the fixing buckle 43 is used to reinforce the connection between the drainage long tube 44 and the vertically arranged detection core 42; the shape of the drainage short tube 46 is cylindrical, and the shape of the drainage long tube 44 is as follows,

[0038] The long drainage tube 44 is used to guide and drain the measured gas introduced into the pressure test pipe port 102 at a 180-degree angle. The specific structure is that the long drainage tube 44 includes a horizontally arranged first connecting tube 441, and the two ends of the first connecting tube 441 are respectively connected to the first sealing connector 442 and the second sealing connector 443. The first sealing connector 442 and the second sealing connector 443 are vertically arranged at the two ends of the first connecting tube 441, and the openings are both facing downward; the opening of the first sealing connector 442 is connected to the upper end of the vertically arranged detection core 42; the opening of the second sealing connector 443 is connected to the corresponding pressure test pipe port 102; a third sealing joint 103 is provided in the pressure test pipe port 102 corresponding to the second sealing connector 443 in the outer shell 1, and the third The sealing joint 103 and the second sealing connector 443 are sealed and connected; thereby, the gas to be tested at the pressure test pipe mouth 102 is drained and guided, and the pipeline structure buffers the incoming gas, so that high-speed carbon deposits adhere to the drainage long tube 44, away from the vertically arranged detection core 42; in addition, nitrogen oxides form an acidic solution when they meet water vapor, which is difficult to turn, and flow down along the second sealing connector 443, so that it is difficult to contact the metal pressure diaphragm 47, thereby avoiding corrosion; in addition, the gas to be tested entering from the pressure test pipe mouth 101 passes through the first connecting pipe 441, partially protecting the metal pressure diaphragm 47, and also attaches carbon deposits, thereby realizing protection of both ends of the vertically arranged detection core 42; corrosion-resistant gaskets and sealing rings are added to the above sealing connections;

[0039] In addition, the metal pressure diaphragm 47 can withstand higher impact forces and is corrosion-resistant, protecting the sintering seat from corrosion; the first spring plate 41 is provided with a first flexible plate 45 electrically connected to the vertically arranged detection core 42, and the first flexible plate 45 is provided with circuits and circuit elements. The first flexible plate 45 is also electrically connected to the electrical connector 3 for transmitting detection signals and avoiding contact with the gas being measured, ultimately enabling the detection unit to withstand the influence of high-speed carbon deposition in the exhaust gas circuit and the corrosion of nitrogen oxides forming an acidic solution when they meet water vapor, thereby improving its service life, increasing detection accuracy, and enhancing its durability.

[0040] Embodiment 2

[0041] like Figure 7-Figure 10 As shown, the detection core in the second detection unit 5 is in a horizontally arranged state and has a corresponding drainage pipe structure;.

[0042] The horizontal detection core 53 has a metal pressure diaphragm 47 protecting its two ends. The horizontal detection core 53 is installed in the housing 1 through a second clip plate 51. The second clip plate 51 matches the sintering seat of the horizontal detection core 53. The second clip plate 51 is provided with a mounting hole matching the sintering seat. The drainage pipe is symmetrically sealed and connected to the two ends of the horizontal detection core 53, and is connected to the pressure test pipe port 102 and the pressure test pipe port 101.

[0043] The symmetrical drainage pipe 52 is used to guide and drain the measured gas introduced into the pressure test pipe port 102 and the pressure test pipe port 101 at a 180-degree angle; the specific structure is as follows: the symmetrical drainage pipe includes a second connecting pipe 521, the upper end of the second connecting pipe 521 is closed, and the lower end is open, and the opening of the second connecting pipe 521 is coaxially connected to a third sealing connector 522, and is connected to the pressure test pipe port 102 or the pressure test pipe port 101, and the tube wall of the closed end of the second connecting pipe 521 is connected to a fourth sealing connector 522. The fourth sealing joint 523 is horizontally arranged and sealedly connected to the horizontal detection core 53; the horizontally arranged detection core 53 is electrically connected to the second flexible plate 54, on which the circuit and circuit elements are arranged. The second flexible plate 54 is also electrically connected to the electrical connector 3, and corrosion-resistant gaskets and sealing rings are added to the above sealing connections to buffer the exhaust gas in the vehicle exhaust gas recirculation system and keep carbon deposits away from the horizontally arranged detection core 53, thereby increasing its service life and increasing the detection accuracy.

[0044] When using:

[0045] (1) The gas to be tested enters the drainage pipes connected to the two ends of the detection core from the pressure test pipe ports 101 and 102, respectively, so that the pressure at the two ends of the detection core is detected. When the gas to be tested flows in the drainage pipes, the carbon deposits generated at high speed in the gas to be tested can be buffered and attached to the wall of the drainage pipes, thereby separating the carbon deposits from the detection core to prevent them from affecting the detection effect.

[0046] (2) The guiding structure of the drainage pipe makes it difficult for nitrogen oxides in the measured gas to turn to an acidic solution when they meet water vapor, thus avoiding corrosion of the detection core. In addition, the detection core of the metal pressure diaphragm is protected to make it corrosion-resistant and impact-resistant.

[0047] To sum up, the present invention solves the problem that when the EGR differential pressure sensor in the prior art is in use, the residual high-temperature exhaust gas and fast-deposited carbon particles in the exhaust gas circuit may damage the piezoresistive detection element, and the nitrogen oxides may form an acidic solution when meeting water vapor, which may easily corrode the piezoresistive detection element and circuit of the sensor.

[0048] The beneficial effects of the present invention are as follows: by adding a drainage pipe with a guiding and drainage function to the detection core, the measured gas is separated from other components of the sensor and only contacts the detection part of the detection core, thereby reducing corrosion; the guidance of the drainage pipe has a buffering effect on the measured gas with a large impact force, and at the same time makes the carbon deposit particles adhere to the inner wall of the drainage pipe, separating the carbon deposit and the detection core to avoid corrosion; in addition, due to the guidance of the drainage pipe, nitrogen oxides form an acidic solution when they meet water vapor and are difficult to contact the detection core, thereby avoiding corrosion, withstanding the influence of high-speed carbon deposition, improving service life and increasing durability; by setting a metal pressure diaphragm on the detection core, the metal pressure diaphragm is in contact with the measured gas to avoid corrosion and also withstand impact; the connection method of the horizontally or vertically arranged detection core with the outer shell and the flexible plate is simple, which is convenient for production and processing.

[0049] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An EGR differential pressure sensor, comprising a housing (1) and an upper cover (2) covering the housing, wherein a detection unit is provided in the housing (1), and an electrical connector (3) electrically connected to the detection unit is provided on the upper cover (2); the housing (1) is also provided with two pressure test pipe ports for introducing a gas to be tested into the detection unit, characterized in that: The detection unit includes a detection core and a drainage pipe, wherein the drainage pipe is connected to both ends of the detection core, and the drainage pipe is also connected to the pressure test pipe port, and the drainage pipe is used to guide the detection gas drained from the pressure test pipe port to the detection core; The detection core is vertically arranged inside the housing (1); The drainage pipeline comprises a short drainage tube (46) and a long drainage tube (44); the short drainage tube (46) is coaxially and sealedly connected to the lower end of a vertically arranged detection core; the long drainage tube (44) is sealedly connected to the upper end of the vertically arranged detection core; The long drainage tube (44) is used for guiding and draining the measured gas introduced into the pressure test pipe port at a 180-degree angle; the long drainage tube (44) comprises a first connecting tube (441), the two ends of the first connecting tube (441) are respectively connected to a first sealing connector (442) and a second sealing connector (443), the first sealing connector (442) and the second sealing connector (443) are vertically arranged at the two ends of the first connecting tube (441), and the openings are both facing downwards; the opening of the first sealing connector (442) is sealed and connected to the upper end of the vertically arranged detection core; the opening of the second sealing connector (443) is connected to the pressure test pipe port.

2. The EGR differential pressure sensor according to claim 1, characterized in that: The detection core is vertically arranged inside the housing (1) via a first clamping spring plate (41).

3. The EGR differential pressure sensor according to claim 1, characterized in that: A third sealing joint (103) is provided in the pressure test pipe opening in the housing (1) that is connected to the second sealing joint (443), and the third sealing joint (103) is sealedly connected to the second sealing joint (443).

4. The EGR differential pressure sensor according to claim 2, characterized in that: The first spring plate (41) is also connected to a fixing buckle (43), and the fixing buckle (43) is used to reinforce the connection between the drainage long tube (44) and the vertically arranged detection core.

5. An EGR differential pressure sensor, comprising a housing (1) and an upper cover (2) covering the housing, wherein a detection unit is arranged in the housing (1), and an electrical connector (3) electrically connected to the detection unit is arranged on the upper cover (2); the housing (1) is also provided with two pressure test pipe openings for introducing a gas to be tested into the detection unit, characterized in that: The detection unit includes a detection core and a drainage pipe, wherein the drainage pipe is connected to both ends of the detection core, and the drainage pipe is also connected to the pressure test pipe port, and the drainage pipe is used to guide the detection gas drained from the pressure test pipe port to the detection core; The detection core is horizontally arranged inside the housing (1); The drainage pipes are two identical drainage pipes, and are symmetrically sealed and connected at two ends of a horizontally arranged detection core; The drainage pipe is used for guiding and draining the gas to be tested introduced into the pressure test pipe mouth at a 180-degree angle; the drainage pipe comprises a second connecting pipe (521) arranged vertically; the upper end of the second connecting pipe (521) is closed and the lower end is open; a third sealing connector (522) is coaxially connected to the opening of the second connecting pipe (521), and the third sealing connector (522) is connected to the pressure test pipe mouth; a fourth sealing joint (523) is connected to the pipe wall of the closed end of the second connecting pipe (521); the fourth sealing joint (523) is arranged horizontally and is sealed and connected to both ends of the horizontally arranged detection core.

6. The EGR differential pressure sensor according to claim 5, characterized in that: The detection core is horizontally arranged inside the housing (1) via a second clip plate (51).

7. An EGR differential pressure sensor according to claim 1 or 5, characterized in that: The detection core body comprises a sintered seat with a pressure detection element arranged inside and metal pressure diaphragms arranged at both ends of the sintered seat.

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