EGR valve and detection method

Abstract

The invention discloses an EGR valve and a detection method, and relates to the technical field of vehicle engines. According to the main technical scheme, an air channel is formed in a valve body, an air outlet and an end cover mounting opening are formed in the two ends of the air channel respectively, and a valve seat is arranged in the air channel; the cross sectional area of the air channel is gradually increased in the direction from the valve seat to the end cover installation opening. An air inlet is formed in the valve body and located in the side, away from the air outlet, of the valve seat, and the air inlet communicates with the air channel. The cone valve is arranged in the air channel; the side, away from the air inlet, of the cone valve is attached to the air channel, and when the cone valve moves towards the end cover along the valve seat, the gap between the side, close to the air inlet, of the cone valve and the air channel is gradually increased. According to the method, the exhaust gas circulation area can be adjusted more finely according to the working state of the engine, then the exhaust gas recirculation amount regulation and control capacity is enhanced, and the adjustment flexibility and accuracy are improved. And meanwhile, the purposes of improving the regulation and control efficiency of the exhaust gas recirculation amount and further improving the regulation flexibility and precision are expected to be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle engines, and particularly relates to an EGR valve and a detection method. Background Art

[0002] EGR (Exhaust Gas Recirculation) is the recirculation of exhaust gas from the engine. It is a technology that reintroduces the exhaust gas discharged from the engine into the intake pipe, mixes it with fresh gas, and then enters the combustion chamber for combustion. The EGR valve is a mechatronic product installed on a vehicle to control the amount of exhaust gas recirculation.

[0003] When the EGR valve works, the valve stem drives the cone valve to move in the air passage, so that the exhaust gas can flow in through the air inlet, and after passing through the gap between the cone valve and the side wall of the air passage, it flows into the combustion chamber from the air outlet. The existing EGR valve, as Figure 1 shown, during the movement of the cone valve, the gap between the cone valve and the side wall of the air passage remains almost unchanged, greatly reducing the flexibility and accuracy of gas flow regulation. Summary of the Invention

[0004] The purpose of the present invention is to provide an EGR valve and a detection method, which solve the problem of low flexibility and accuracy when the existing EGR valve regulates the gas flow.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, an EGR valve is provided, which includes a valve seat, a valve body, and a cone valve. An air passage is provided in the valve body. The two ends of the air passage are respectively an air outlet and an end cap mounting port, and a valve seat is provided in the air passage. Among them, the cross-sectional area of the air passage gradually increases from the valve seat to the direction of the end cap mounting port; an air inlet is provided on the valve body, the air inlet is located on the side of the valve seat away from the air outlet, and the air inlet is communicated with the air passage; the cone valve is arranged in the air passage. Among them, the side of the cone valve away from the air inlet fits against the air passage, and when the cone valve moves from the valve seat towards the end cap, the gap between the side of the cone valve close to the air inlet and the air passage gradually increases.

[0007] In a second aspect, a detection method is provided. The detection method is applicable to the EGR valve described in the first aspect. The detection method includes an operation for detecting the sealing performance of the guide sleeve:

[0008] The operation for detecting the sealing performance of the guide sleeve includes:

[0009] Seal the air inlet and make the sliding seal state between the cone valve and the air passage;

[0010] Preset several acquisition positions on the air passage, and the several acquisition positions are arranged in sequence along the direction from the valve seat to the end cap mounting port;

[0011] Fill a certain amount of gas medium into the first target chamber from the air outlet; the first target chamber is formed between the cone valve, the air passage and the air outlet;

[0012] Obtain the first measured air pressure and the predicted air pressure in the first target chamber when the cone valve moves from the valve seat to the acquisition position;

[0013] Calculate the air pressure difference between the first measured air pressure and the predicted air pressure, and judge whether each air pressure difference is less than the air pressure threshold; if so, it is considered that the sealing performance of the guide sleeve is qualified, if not, it is considered that the sealing performance of the guide sleeve is unqualified.

[0014] A further solution is that the detection method further includes an operation for detecting the sealing performance of the valve seat:

[0015] The operation for detecting the sealing performance of the valve seat includes:

[0016] Make the air inlet in a sealed state and fit the cone valve onto the valve seat;

[0017] Fill a gas medium into the second target chamber from the end cover mounting port; the second target chamber is formed between the cone valve, the air passage, the air inlet and the end cover mounting port;

[0018] Real-time collect the second measured air pressure in the second target chamber and construct a fitting curve of the second measured air pressure changing with time;

[0019] Judge whether the actual slope of the fitting curve is greater than the slope threshold; if so, it is considered that the sealing performance of the valve seat is qualified, if not, it is considered that the sealing performance of the valve seat is unqualified.

[0020] A further solution is that the process of obtaining the predicted air pressure includes:

[0021] Obtain the temperature, molar amount of the gas medium in the first target chamber, and the volume of the first target chamber;

[0022] Process the temperature, molar amount and volume to obtain the predicted air pressure.

[0023] A further solution is that the calculation formula for the predicted air pressure is:

[0024]

[0025] where, is the predicted air pressure; is the molar amount of the gas medium; is the ideal gas constant; is the temperature compensation coefficient; is the temperature; is the volume compensation coefficient; is the volume of the first target chamber.

[0026] A further solution is: when the duration for which the cone valve is in the collection position is greater than or equal to a duration threshold, obtain the first measured air pressure in the first target chamber.

[0027] A further solution is: the first measured air pressure is greater than the ambient air pressure outside the first target chamber.

[0028] A further solution is: the temperature compensation coefficient The acquisition process includes:

[0029] Obtain the first frictional heat between the valve stem and the guide sleeve, and the second frictional heat between the cone valve and the air passage;

[0030] Perform calculation processing on the first frictional heat and the second frictional heat to obtain the temperature compensation coefficient .

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] By moving the cone valve along the valve seat towards the end cap mounting port / along the end cap mounting port towards the cone valve, the gap between the cone valve and the side wall of the air passage is gradually increased or decreased. It is expected to achieve more precise adjustment of the exhaust gas flow area according to the working state of the engine, thereby enhancing the regulation ability of the exhaust gas recirculation amount to improve the adjustment flexibility and accuracy. At the same time, the exhaust gas flows from the gap between the side of the cone valve close to the intake port and the air passage to the outlet, reducing unnecessary flow resistance and optimizing the exhaust gas flow path, aiming to improve the regulation efficiency of the exhaust gas recirculation amount and further improve the adjustment flexibility and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic structural diagram of an existing EGR valve;

[0034] Figure 2 is a schematic structural diagram of an EGR valve in this embodiment;

[0035] Figure 3 is a schematic flow diagram of a detection method in this embodiment.

[0036] Markings in the drawings and corresponding component names:

[0037] 1-valve seat; 2-valve body; 3-air passage; 4-outlet; 5-end cap mounting port; 6-intake port; 7-cone valve; 8-valve stem; 9-guide sleeve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be further described below with reference to the drawings.

[0039] Embodiment 1: This embodiment provides an EGR valve, as Figure 2 shown, which includes a valve seat 1, a valve body 2, and a tapered valve 7. An air passage 3 is provided inside the valve body 2. The two ends of the air passage 3 are respectively an air outlet 4 and an end cover mounting port 5, and the valve seat 1 is provided inside the air passage 3. Among them, the cross-sectional area of the air passage 3 gradually increases from the valve seat 1 towards the end cover mounting port 5. An air inlet 6 is provided on the valve body 2. The air inlet 6 is located on the side of the valve seat 1 away from the air outlet 4, and the air inlet 6 communicates with the air passage 3. The tapered valve 7 is arranged inside the air passage 3. Among them, the side of the tapered valve 7 away from the air inlet 6 fits against the air passage 3, and when the tapered valve 7 moves along the valve seat 1 towards the end cover, the gap between the side of the tapered valve 7 close to the air inlet 6 and the air passage 3 gradually increases.

[0040] Exemplarily, during implementation, the EGR valve includes a valve body 2. An air passage 3 is provided inside the valve body 2. The two ends of the air passage 3 penetrate through the valve body 2, and the two ends of the air passage 3 respectively form an air outlet 4 and an end cover mounting port 5.

[0041] The valve seat 1 is connected inside the air passage 3 by means of clamping, welding, or screwing, etc., and the air outlet 4 and the end cover mounting port 5 are located on both sides of the valve seat 1.

[0042] An air inlet 6 is opened on the side wall of the valve body 2. The air inlet 6 is located on the side of the valve seat 1 close to the end cover mounting port 5, and the air inlet 6 communicates with the part of the air passage 3 close to the end cover mounting port 5.

[0043] The EGR valve further includes a guide sleeve 9 and a valve stem 8. The guide sleeve 9 is penetrated through the valve body 2. The guide sleeve 9 is connected to the valve body 2 by means of screwing and fixing, welding and fixing, etc., and the guide sleeve 9 is hermetically connected to the valve body 2 through a sealing ring. The valve stem 8 is penetrated through the guide sleeve 9. The valve stem 8 is hermetically connected to the guide sleeve 9 through a sealing ring, and one end of the valve stem 8 is penetrated through the air passage 3.

[0044] The tapered valve 7 is arranged inside the air passage 3. The tapered valve 7 is connected to one end of the valve stem 8 by means of interference fit, screwing and fixing, welding and fixing, etc., and the tapered valve 7 is located on the side of the valve seat 1 close to the end cover mounting port 5. And when the tapered valve 7 is fitted on the valve seat 1, the air passage 3 is in a closed state.

[0045] Among them, the cross-sectional area of the air passage 3 gradually increases from the valve seat 1 along the direction from the valve seat 1 towards the end cover mounting port 5. The side of the tapered valve 7 away from the air inlet 6 fits against the air passage 3, and when the tapered valve 7 moves along the valve seat 1 towards the end cover mounting port 5, the gap between the side of the tapered valve 7 close to the air inlet 6 and the side wall of the air passage 3 gradually increases.

[0046] During use, after the exhaust gas flows in through the intake port 6, it then flows towards the outlet port 4 through the gap between the side of the conical valve 7 close to the intake port 6 and the air passage 3. At this time, the conical valve 7 moves along the valve seat 1 towards the end cap mounting port 5 / along the end cap mounting port 5 towards the conical valve 7, so that the gap between the conical valve 7 and the side wall of the air passage 3 gradually increases or decreases. It is expected to achieve the purpose of more precisely adjusting the exhaust gas flow area according to the working state of the engine, thereby enhancing the control ability of the exhaust gas recirculation amount, and improving the adjustment flexibility and accuracy. At the same time, the exhaust gas flows towards the outlet port 4 through the gap between the side of the conical valve 7 close to the intake port 6 and the air passage 3, reducing unnecessary flow resistance and optimizing the exhaust gas flow path, with the expectation of achieving the purpose of improving the control efficiency of the exhaust gas recirculation amount and further enhancing the adjustment flexibility and accuracy.

[0047] Embodiment 2: This embodiment provides a detection method. As Figure 3 shown, the detection method is applicable to the EGR valve described in Embodiment 1. The detection method includes an operation for detecting the sealing performance of the guide sleeve:

[0048] The operation for detecting the sealing performance of the guide sleeve includes:

[0049] S100. Keep the intake port in a sealed state and keep the conical valve and the air passage in a sliding seal state;

[0050] Exemplarily, during implementation, the EGR valve is fixed on the detection fixture, and the intake port is sealed by using the sealing structure on the detection fixture. At the same time, a sliding seal is performed between the conical valve and the air passage. That is to say, during the process of the conical valve moving along the valve seat towards the end cap mounting port / along the end cap mounting port towards the valve seat, the conical valve and the air passage are always in a sealed state. It is expected to achieve the purpose of constructing the required sealed environment for guide sleeve detection, reducing the leakage risk of other parts during the guide sleeve seal detection, and thus improving the accuracy of the guide sleeve seal performance detection.

[0051] S200. Preset a number of collection positions on the air passage, and these collection positions are arranged in sequence along the direction from the valve seat to the end cap mounting port;

[0052] Exemplarily, during implementation, a number of collection positions are preset on the air passage, and these collection positions are evenly arranged along the direction from the valve seat to the end cap mounting port starting from the valve seat, and these collection positions are sequentially marked as 、 …… 。For example, when the conical valve is fitted in the valve seat, collection position marks are made on the part of the valve stem extending outside the valve body. The number of collection position marks is set to be a number, and these collection position marks are arranged in sequence along the valve stem in the direction away from the valve body, and are sequentially marked as 、 …… , and the several acquisition position identifiers correspond one-to-one with the acquisition positions on the air passage. That is to say, when the valve stem moves along the valve seat towards the end cap mounting port to the acquisition position identifier (for example, the acquisition position identifier is marked on the valve stem. When the marking line representing the acquisition position identifier coincides with the valve body), it means that the cone valve moves to the acquisition position . When the valve stem moves along the valve seat towards the end cap mounting port to the acquisition position identifier (for example, the acquisition position identifier is marked on the valve stem. When the marking line representing the acquisition position identifier coincides with the valve body), it means that the cone valve moves to the acquisition position ... When the valve stem moves along the valve seat towards the end cap mounting port to the acquisition position identifier (for example, the acquisition position identifier is marked on the valve stem. When the marking line representing the acquisition position identifier coincides with the valve body), it means that the cone valve moves to the acquisition position . The purpose is to facilitate the staff to identify the acquisition position where the cone valve is located from the exposed part of the valve stem.

[0053] S300. Charge a certain amount of gas medium into the first target chamber from the air outlet; the first target chamber is formed among the cone valve, the air passage and the air outlet;

[0054] Seal the gas supply end of the gas supply device to the air outlet so that the air outlet, the air inlet, and the space between the cone valve and the air passage are all in an ideal sealing state. The ideal sealing state means that during the sealing performance detection of the guide sleeve, the leakage amount is 0 or the leakage amount is small and can be ignored, and it does not affect the judgment of the sealing performance of the guide sleeve. When the cone valve is adapted to the valve seat, a certain amount of gas medium is charged into the first target chamber formed among the cone valve, the air passage and the air outlet by the gas supply device. Among them, the gas medium can be selected as air, nitrogen, etc.

[0055] Considering that there may be air in the air passage itself. Therefore, in order to reduce the operation of evacuating the air passage, the gas medium in this embodiment is preferably air.

[0056] Make the air pressure in the first chamber greater than the air pressure outside the first chamber. And use the pressure acquisition device to acquire the air pressure in the first chamber, denoted as the first initial air pressure. When the continuous duration of the cone valve adapted in the valve seat is greater than or equal to the duration threshold, acquire the air pressure in the first chamber again, denoted as the second initial air pressure. Among them, the duration threshold can be set to 5 min, 10 min, 15 min, etc. according to historical data. There is no specific limit on the duration threshold here.

[0057] Calculate the pressure difference between the second initial pressure and the first initial pressure, denoted as the initial pressure difference, and determine whether the initial pressure difference is less than the pressure threshold. If the initial pressure difference is less than the pressure threshold, it is considered that the sealing performance of the guide sleeve is qualified when the cone valve is adapted to the valve seat. If the initial pressure difference is greater than or equal to the pressure threshold, it is considered that the sealing performance of the guide sleeve is unqualified when the cone valve is adapted to the valve seat.

[0058] Among them, the pressure threshold can be calculated from the allowable leakage amount in historical data. In an ideal state, this pressure threshold can be considered as 0.

[0059] S400. Obtain the first measured pressure and the predicted pressure in the first target chamber when the cone valve moves from the valve seat to the acquisition position;

[0060] Exemplarily, during the implementation process, drive the valve stem to move along the valve seat towards the end cover mounting port to the acquisition position mark , at this time, the cone valve moves to the acquisition position . When the duration of the cone valve at the acquisition position is greater than or equal to the duration threshold, collect the pressure in the first chamber, denoted as the first measured pressure . And obtain the predicted pressure in the first chamber . Then, drive the valve stem to move along the valve seat towards the end cover mounting port to the acquisition position mark , at this time, the cone valve moves to the acquisition position . When the duration of the cone valve at the acquisition position is greater than or equal to the duration threshold, collect the pressure in the first chamber, denoted as the first measured pressure . And obtain the predicted pressure in the first chamber ... Drive the valve stem to move along the valve seat towards the end cover mounting port to the acquisition position mark , at this time, the cone valve moves to the acquisition position . When the duration of the cone valve at the acquisition position is greater than or equal to the duration threshold, collect the pressure in the first chamber, denoted as the first measured pressure . And obtain the predicted pressure in the first chamber .

[0061] S500. Calculate the pressure difference between the first measured pressure and the predicted pressure, and determine whether each pressure difference is less than the pressure threshold; if so, it is considered that the sealing performance of the guide sleeve is qualified, if not, it is considered that the sealing performance of the guide sleeve is unqualified.

[0062] Exemplarily, during the implementation process, calculate the first measured pressure and the predicted pressure , denote the pressure difference as , the first measured pressure The air pressure difference from the predicted air pressure is denoted as ……the first measured air pressure The air pressure difference from the predicted air pressure is denoted as .

[0063] Judge respectively between and the air pressure threshold value, between and the air pressure threshold value…… between and the air pressure threshold value. When , …… are all less than the air pressure threshold value, it is considered that the sealing performance of the guide sleeve is qualified. When , …… at least one of them is greater than or equal to the air pressure threshold value, it is considered that the sealing performance of the guide sleeve is unqualified.

[0064] In the detection method of this embodiment, during the process of the conical valve moving along the valve seat towards the end cover mounting port, the air pressure is measured at multiple acquisition positions to simulate the sealing performance of the guide sleeve during the movement of the valve stem. It is expected to more accurately detect the sealing performance of the guide sleeve during the entire working stroke, thereby ensuring that the risk of exhaust gas leakage can be effectively reduced under various working conditions, so as to ensure the normal operation of the EGR system.

[0065] In the detection method of this embodiment, considering factors such as the material of the EGR valve itself and the allowable leakage amount of the guide sleeve, by setting the air pressure threshold value, it is expected to achieve the purpose of reducing the risk of misjudging the sealing performance of the guide sleeve.

[0066] In this embodiment, the detection method further includes an operation for detecting the sealing performance of the valve seat: The operation for detecting the sealing performance of the valve seat includes:

[0067] Make the air inlet in a sealed state and fit the conical valve onto the valve seat;

[0068] Exemplarily, during the implementation process, the EGR valve is fixed on the detection tooling, and the air inlet is sealed by using the sealing structure on the detection tooling. And the conical valve is fitted onto the valve seat.

[0069] Fill the gas medium into the second target chamber from the end cover mounting port; the second target chamber is formed among the conical valve, the air passage, the air inlet and the end cover mounting port;

[0070] Seal the gas supply end of the gas supply device to the end cap mounting port so that both the air inlet and the end cap mounting port are in an ideal sealed state. The ideal sealed state means that during the valve seat sealing performance test, the leakage rate is 0 or the leakage rate is small enough to be negligible and does not affect the judgment of the guide sleeve sealing performance. Fill a certain amount of gas medium into the second target chamber formed by the cone valve, the air passage, the air inlet, and the end cap mounting port through the gas supply device until the air pressure in the second chamber is greater than the air pressure outside the second chamber. Among them, the gas medium can be selected as air, nitrogen, etc.

[0071] Considering that there may be air in the air passage itself. Therefore, in order to reduce the operation of evacuating the air passage, the gas medium in this embodiment is preferably air.

[0072] Collect the second measured air pressure in the second target chamber in real time and construct a fitting curve of the second measured air pressure changing with time;

[0073] Exemplarily, during the implementation process, collect the second measured air pressure in the second target chamber every once in a while. For example, The second measured air pressure collected at time is denoted as ; The second measured air pressure collected at time is denoted as . Among them, < <……< . Integrate each collection time and the corresponding second measured air pressure into a series of discrete data points, denoted as ( , ), ( , )... ( , ). And through fitting algorithms such as the least squares method and nonlinear regression, fit the discrete data points to obtain a fitting curve of the second measured air pressure changing with time .

[0074] Judge whether the actual slope of the fitting curve is greater than the slope threshold. If so, it is considered that the valve seat sealing performance is qualified; if not, it is considered that the valve seat sealing performance is unqualified.

[0075] Exemplarily, during the implementation process, the actual slope of the fitting curve refers to the tangent slope at each point on the fitting curve. Calculate the first derivative of the fitting curve , and judge the first derivative Are they all greater than the slope threshold? If so, the seat sealing performance is considered qualified; if not, the seat sealing performance is considered unqualified.

[0076] In this embodiment, considering that under ideal conditions, due to the existence of conditions such as the material of the EGR valve itself and the allowable leakage amount, the air pressure in the second target chamber will gradually decrease over time. That is to say, the slope of the fitting curve is negative. Therefore, it is set that when the first derivative of the fitting curve is all greater than the slope threshold, the seat sealing performance is considered qualified.

[0077] Among them, the slope threshold can be set as follows: Test a batch of EGR valves with known good sealing performance, and record the data of the air pressure changing with time under the same detection conditions. Then, use statistical methods to analyze the data to determine a suitable slope threshold that can distinguish the "good" and "bad" sealing performance of the EGR valve.

[0078] In this embodiment, the process of obtaining the predicted air pressure includes:

[0079] Obtain the temperature, molar amount of the gas medium in the first target chamber, and the volume of the first target chamber;

[0080] Process the temperature, molar amount and volume to obtain the predicted air pressure.

[0081] In this embodiment, the calculation formula of the predicted air pressure is:

[0082]

[0083] Among them, is the predicted air pressure; is the molar amount of the gas medium; is the ideal gas constant; is the temperature compensation coefficient; is the temperature; is the volume compensation coefficient; is the volume of the first target chamber.

[0084] In this embodiment, considering that during the movement of the cone valve along the seat towards the end cover mounting port, the heat generated by the friction between the cone valve and the airway side wall, and the heat generated by the friction between the valve stem and the guide sleeve will cause a regional increase in the temperature of the gas medium in the first target chamber, and further cause a deviation between the measured temperature and the actual temperature. Therefore, the temperature compensation coefficient is set to expect to reduce the deviation between the measured temperature and the actual temperature, and further improve the accuracy of the guide sleeve sealing detection.

[0085] Meanwhile, considering that the air passage has a special-shaped structure with a gradually increasing cross-sectional area from the valve seat along the direction of the valve seat to the end cover mounting port, it may cause measurement errors in the volume of the first target chamber. Therefore, a volume compensation coefficient is set to reduce the volume measurement error and further improve the accuracy of the guide sleeve sealing detection.

[0086] Among them, the setting method of the volume compensation coefficient is as follows: Based on the design drawings and technical specifications of the EGR valve, calculate the theoretical volume of the first target chamber when the cone valve is at different acquisition positions. Use computer-aided design (CAD) software to create a three-dimensional model of the internal structure of the EGR valve, and use computational fluid dynamics (CFD) simulation tools to analyze the actual volume of the first target chamber when the cone valve is at different acquisition positions. Determine the volume compensation coefficient through the difference between the theoretical volume and the actual volume.

[0087] During the movement of the cone valve, since the change in the cross-sectional area of the air passage is non-linear, the volume compensation coefficient may not be fixed but change with the position of the cone valve.

[0088] In this embodiment, when the duration of the cone valve at the acquisition position is greater than or equal to the duration threshold, the first measured air pressure in the first target chamber is obtained. By setting a fixed waiting time, it is ensured that the inside of the EGR valve is in a relatively stable state, aiming to more accurately capture the actual air pressure change in the first target chamber and further reduce the risk of measurement errors caused by transient effects.

[0089] In this embodiment, the first measured air pressure is greater than the ambient air pressure outside the first target chamber. By making the air pressure in the first target chamber higher than the external ambient air pressure, the detection ability for micro-leaks can be significantly improved, aiming to improve the detection accuracy.

[0090] In this embodiment, the acquisition process of the temperature compensation coefficient includes:

[0091] Obtain the first frictional heat between the valve stem and the guide sleeve, and the second frictional heat between the cone valve and the air passage;

[0092] Exemplarily, during the implementation process, estimate the first frictional heat generated by friction between the valve stem and the guide sleeve through the frictional force between the valve stem and the guide sleeve and the displacement of the cone valve ; and estimate the second frictional heat generated by friction between the cone valve and the air passage through the frictional force between the cone valve and the air passage and the displacement of the cone valve .

[0093] Perform calculation processing on the first frictional heat and the second frictional heat to obtain the temperature compensation coefficient .

[0094] Exemplarily, during implementation, according to the first frictional heat , the second frictional heat , as well as the specific heat capacity at constant volume and the molar amount of the gas in the gas medium, calculate the temperature change caused by the first frictional heat and the second frictional heat on the gas medium.

[0095] Among them, the calculation method of the temperature change is as follows:

[0096]

[0097] Among them, is the temperature change; is the molar amount of the gas medium; is the specific heat capacity at constant volume of the gas medium; is the first frictional heat; is the second frictional heat.

[0098] Among them, the calculation method of the temperature compensation coefficient is as follows:

[0099]

[0100] Among them, is the temperature compensation coefficient; is the temperature change; is the temperature.

[0101] Although the present invention has been described herein with reference to multiple illustrative embodiments of the present invention, it should be understood that those skilled in the art can design many other modifications and implementations, which will fall within the scope of the principles and spirit disclosed in this application. More specifically, within the scope of the disclosure, the drawings, and the claims of this application, various variations and improvements can be made to the components and / or the layout of the subject combination layout. In addition to the variations and improvements made to the components and / or the layout, other uses will also be apparent to those skilled in the art.

Claims

1. An EGR valve, characterized in that: include: Valve seat (1); A valve body (2), wherein an air passage (3) is arranged in the valve body (2), wherein two ends of the air passage (3) are respectively an air outlet (4) and an end cover mounting opening (5), and a valve seat (1) is arranged in the air passage (3); wherein the cross-sectional area of ​​the air passage (3) gradually increases from the valve seat (1) toward the end cover mounting opening (5); an air inlet (6) is arranged on the valve body (2), wherein the air inlet (6) is located on a side of the valve seat (1) away from the air outlet (4), and the air inlet (6) is communicated with the air passage (3); A cone valve (7), wherein the cone valve (7) is arranged in the air passage (3); wherein a side of the cone valve (7) away from the air inlet (6) is in contact with the air passage (3), and when the cone valve (7) moves along the valve seat (1) toward the end cover, a gap between a side of the cone valve (7) close to the air inlet (6) and the air passage (3) gradually increases.

2. A detection method, characterized in that: The detection method is applicable to the EGR valve as claimed in claim 1, and the detection method includes a guide sleeve sealing detection operation: The guide sleeve sealing detection operation includes: The air inlet is in a sealed state, and the cone valve and the airway are in a sliding sealed state; A plurality of collection positions are preset on the airway, and the plurality of collection positions are arranged in sequence along the direction from the valve seat to the end cover installation opening; A fixed amount of gas medium is filled into the first target chamber from the gas outlet; the first target chamber is formed between the cone valve, the gas channel and the gas outlet; Acquire a first measured air pressure and a predicted air pressure in a first target chamber when the cone valve moves from a valve seat to a collection position; The air pressure difference between the first measured air pressure and the predicted air pressure is calculated, and it is determined whether each air pressure difference is less than the air pressure threshold; if so, it is considered that the sealing of the guide sleeve is qualified, if not, it is considered that the sealing of the guide sleeve is unqualified.

3. The detection method according to claim 2, characterized in that: It also includes valve seat tightness detection operations: The valve seat sealing detection operation includes: Make the air inlet in a sealed state and make the cone valve fit on the valve seat; Filling the gas medium into the second target chamber from the end cover installation port; the second target chamber is formed between the cone valve, the air channel, the air inlet and the end cover installation port; collecting a second measured air pressure in a second target chamber in real time, and constructing a fitting curve of the second measured air pressure changing with time; It is determined whether the actual slope of the fitting curve is greater than the slope threshold. If so, it is considered that the valve seat sealing is qualified; if not, it is considered that the valve seat sealing is unqualified.

4. The detection method according to claim 2, characterized in that: The process of obtaining the predicted air pressure includes: obtaining the temperature and molar amount of the gas medium in the first target chamber, and the volume of the first target chamber; Temperature, molarity, and volume are processed to obtain the predicted gas pressure.

5. The detection method according to claim 4, characterized in that: The calculation formula for the predicted air pressure is: in, To predict air pressure; is the molar amount of the gas medium; is the ideal gas constant; is the temperature compensation coefficient; is temperature; is the volume compensation coefficient; is the volume of the first target chamber.

6. The detection method according to claim 4, characterized in that: When the duration of the cone valve being located at the collection position is greater than or equal to the duration threshold, a first measured air pressure in the first target chamber is acquired.

7. The detection method according to claim 4, characterized in that: The first measured air pressure is greater than the ambient air pressure outside the first target chamber.

8. The detection method according to claim 5, characterized in that: The temperature compensation coefficient The acquisition process includes: Obtaining a first friction heat between the valve stem and the guide sleeve, and a second friction heat between the cone valve and the air passage; The first friction heat and the second friction heat are calculated and processed to obtain the temperature compensation coefficient .

Images