Air leakage detection method for vehicle exhaust system
By connecting the work-mounted exhaust pipe with the catalytic muffler tail pipe and the detection of the flow sensor for the vehicle exhaust system, combined with data acquisition and comparison of the OBD communication port, it is solved that it is difficult to accurately detect air leakage in the exhaust system in the prior art. The problem is that efficient and accurate air leakage detection is achieved, and the effectiveness and safety of the test is improved.
Patent Information
- Application Number
- CN202411541607.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-02-07
AI Technical Summary
The prior art is difficult to accurately detect whether there is air leakage in vehicle exhaust systems, resulting in inaccurate emission test results, wasting resources and time, and causing economic losses.
By making tool exhaust pipes, docking with the vehicle's catalytic muffler tail pipe, installing a flow sensor to detect the gas mass flow rate, and connecting it with the vehicle's OBD communication port through the acquisition instrument to collect and compare the turbine outlet exhaust mass flow curve and tool discharge The mass flow curve of the air pipe, determine whether the exhaust system is leaking.
It realizes accurate detection of whether the vehicle exhaust system is leaking, improves the effectiveness of the test, saves test costs, ensures the smooth progress of project development, and reduces safety hazards.
Smart Images
Figure CN119394545A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of vehicle exhaust system leakage detection, and more specifically, to a vehicle exhaust system leakage detection method. Background Art
[0002] When developing new models, vehicle manufacturers need to apply for environmental protection and public announcement certification, including PEMS certification and rotary hub certification. PEMS certification mainly detects whether the exhaust emission indicators meet the standards, while rotary hub certification is a joint test of fuel consumption and emissions, which requires not only fuel consumption testing but also emissions testing. To conduct emissions testing, emission equipment must be installed. The emission equipment must connect a tooling exhaust pipe to the vehicle's exhaust tail pipe. The tooling exhaust pipe is equipped with a flow meter to detect the exhaust flow. At the same time, the exhaust gas emitted by the vehicle is sampled through the tooling exhaust pipe, and then the CO, NOX, and PN components in the sampled exhaust are analyzed to see if they meet the requirements of the regulations.
[0003] One of the prerequisites for the accuracy and validity of the emission test results is that the vehicle must be normal and fault-free, especially the exhaust system must not have air leaks. If the exhaust system leaks, the test results of the emission equipment will be lower than the actual value, and the test results of the emission equipment will be inaccurate, and the test will be invalid. In this case, the test resources and time will be wasted, the project progress will be delayed, and direct and indirect economic losses will be caused. If the exhaust pipe can be checked for air leaks before the test, and the exhaust pipe is ensured to be tested in a state of no air leaks (i.e. normal state), the above problems can be avoided.
[0004] At present, the inspection and detection of vehicle exhaust system leaks mainly rely on visual observation and ear listening. The engine compartment and exhaust pipe space are compact. If there are small cracks in the exhaust pipe, it is not easy to find them with eyes. After the engine is started, the engine noise, cooling fan noise, supercharger noise, etc. are mixed in. If the exhaust pipe leaks, the ear can't hear the sound of exhaust leakage. Therefore, it is difficult to find, identify, and judge whether the exhaust pipe is leaking by visual observation and ear listening. Moreover, after the engine is started, the exhaust pipe temperature is high, which may cause skin burns if approached. The engine belt runs at high speed, which is a safety hazard and people are prohibited from approaching. It is difficult to check whether the exhaust pipe is leaking with the existing method. Summary of the invention
[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art. The purpose of the present invention is to provide a method for detecting air leakage in a vehicle exhaust system, which can accurately check whether there is air leakage in the exhaust pipe.
[0006] The technical solution of the present invention is: a method for detecting air leakage in a vehicle exhaust system, comprising the following steps:
[0007] Step 1. Make a tool exhaust pipe, connect the tool exhaust pipe with the catalytic muffler tail pipe of the vehicle, and ensure that the connection is firm and there is no leakage; the exhaust gas discharged from the catalytic muffler tail pipe flows into the tool exhaust pipe, and then is discharged to the atmosphere after passing through the tool exhaust pipe; the tool exhaust pipe is equipped with a flow sensor, which can detect the mass flow of the gas flowing through the tool exhaust pipe, and send the detected and collected mass flow data to a collection instrument or a computer;
[0008] Step 2. The acquisition instrument or computer is connected to the OBD communication port of the vehicle via a CAN line, and the turbine outlet exhaust mass flow rate in the engine ECU parameters is collected, and the turbine outlet exhaust mass flow rate is aligned with the mass flow rate of the tooling exhaust pipe and then merged to generate a collection file;
[0009] Step 3. Read the acquisition file and convert the acquisition file into an EXCEL spreadsheet file, draw a time-mass flow curve of the exhaust mass flow at the turbine outlet and the mass flow of the tooling exhaust pipe on the same chart, and obtain a turbine outlet exhaust mass flow curve and a tooling exhaust pipe mass flow curve;
[0010] Step 4. Compare the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve. If the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve coincide with each other or have a high degree of agreement, it means that there is no air leakage in the exhaust system of the vehicle; if there is an obvious gap between the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve, and the exhaust mass flow curve at the turbine outlet is higher than the tooling exhaust pipe mass flow curve, it means that there is air leakage in the exhaust system of the vehicle, and each section of the exhaust system needs to be checked in detail.
[0011] As a further improvement, the outer diameter of the tooling exhaust pipe is not less than the outer diameter of the catalytic muffler tail pipe.
[0012] Furthermore, a gasket is provided at the joint between the tooling exhaust pipe and the catalytic muffler tail pipe of the vehicle.
[0013] Furthermore, the tooling exhaust pipe is clamped and tightened to the catalytic muffler tail pipe of the vehicle through a first clamp.
[0014] Furthermore, the tooling exhaust pipe is connected to the catalytic muffler tail pipe of the vehicle via a high temperature resistant rubber tube, and the connection is tightened using a first clamp.
[0015] Furthermore, when the units of the exhaust mass flow rate at the turbine outlet and the mass flow rate of the tooling exhaust pipe are not unified, unit conversion is required, and the conversion formula 1 (g / s) = 1 / 1000*3600 (kg / h) is used to uniformly convert them into units of g / s or kg / h.
[0016] Furthermore, a supporting foot structure is provided at the bottom of the tooling exhaust pipe.
[0017] Furthermore, the support leg structure includes a triangular frame connected to the bottom of the tooling exhaust pipe, springs are respectively provided on both sides of the bottom of the triangular frame, and a pad is provided at the bottom of the spring.
[0018] Furthermore, the triangular frame is connected to the tooling exhaust pipe via a second clamp.
[0019] Furthermore, a connecting plate is provided on the top of the triangular frame, a screw rod passing downward through the connecting plate is provided on the bottom of the second clamp, and nuts for locking the screw rod are respectively provided on the upper and lower sides of the connecting plate.
[0020] Beneficial Effects
[0021] Compared with the prior art, the present invention has the following advantages:
[0022] 1. The present invention does not require the cab above the engine compartment to be raised to detect air leakage by visual observation and listening to the sound, thus reducing physical labor.
[0023] 2. The present invention has high accuracy and efficiency, improves the effectiveness of the test, saves test costs, and ensures the smooth progress of project development, helps to put the product on the market as soon as possible, and brings direct and indirect economic benefits to the enterprise.
[0024] 3. The present invention avoids the potential safety hazard of approaching the running engine and the high-temperature exhaust pipe after starting the engine, thereby improving the safety of work. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 This is a diagram of the tooling exhaust pipe and the catalytic muffler tail pipe being directly connected through the first clamp in the present invention;
[0026] Figure 2 This is a diagram of the tooling exhaust pipe and the catalytic muffler tail pipe being directly connected through a high temperature resistant rubber tube in the present invention;
[0027] Figure 3 It is a schematic diagram of the front view of the exhaust pipe and the supporting foot structure of the tooling in the present invention;
[0028] Figure 4 It is a schematic diagram of the left side structure of the tooling exhaust pipe and the supporting foot structure in the present invention;
[0029] Figure 5 It is the exhaust flow consistency diagram;
[0030] Figure 6 This is a diagram of inconsistent exhaust flow.
[0031] Among them: 1-tooling exhaust pipe, 2-catalytic muffler tail pipe, 3-flow sensor, 4-collection instrument, 5-OBD communication port, 6-engine, 7-gasket, 8-first clamp, 9-high temperature resistant rubber tube, 10-support foot structure, 11-triangular frame, 12-spring, 13-second clamp, 14-connecting plate, 15-screw, 16-nut, 17-gasket. DETAILED DESCRIPTION
[0032] The present invention will be further described below with reference to the specific embodiments in the accompanying drawings.
[0033] See also Figure 1 to Figure 4 A method for detecting a gas leakage in a vehicle exhaust system comprises the following steps 1 to 4:
[0034] Step 1. Make a tool exhaust pipe 1, and connect the tool exhaust pipe 1 with the catalytic muffler tail pipe 2 of the vehicle to ensure that the connection is firm and there is no leakage. The exhaust gas discharged from the catalytic muffler tail pipe 2 flows into the tool exhaust pipe 1, and then is discharged to the atmosphere after passing through the tool exhaust pipe 1. The tool exhaust pipe 1 is equipped with a flow sensor 3, which can detect the mass flow rate of the gas flowing through the tool exhaust pipe 1, and at the same time send the detected and collected mass flow data to the collection instrument 4 or computer.
[0035] Step 2. The collection instrument 4 or computer saves the mass flow of the tooling exhaust pipe 1. At the same time, the collection instrument 4 or computer is connected to the OBD communication port 5 of the vehicle via a CAN line, collects the turbine outlet exhaust mass flow in the ECU parameters of the engine 6, and aligns the turbine outlet exhaust mass flow with the mass flow of the tooling exhaust pipe 1 and then merges them to generate a collection file, which is automatically saved in the storage card of the collection instrument 4 or the computer.
[0036] Step 3. Read the acquisition file from the memory card and convert the acquisition file into an EXCEL spreadsheet file to facilitate various processing such as analysis, calculation, and drawing of the collected data. In this embodiment, the exhaust mass flow rate at the turbine outlet and the mass flow rate of the tooling exhaust pipe 1 are plotted on the same graph as a time-mass flow rate curve to obtain the exhaust mass flow rate curve at the turbine outlet and the tooling exhaust pipe mass flow rate curve.
[0037] Step 4. Compare the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve. If the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve coincide or have a high degree of agreement, it means that there is no air leakage in the vehicle's exhaust system; if there is a significant gap between the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve, and the exhaust mass flow curve at the turbine outlet is higher than the tooling exhaust pipe mass flow curve, it means that there is air leakage in the vehicle's exhaust system, and each section of the exhaust system needs to be checked in detail, such as Figure 5 , Figure 6shown.
[0038] The outer diameter of the tooling exhaust pipe 1 is not less than the outer diameter of the catalytic muffler tail pipe 2, so that the tooling exhaust pipe 1 will not affect the exhaust of the normal working of the vehicle.
[0039] In one embodiment, Figure 1 As shown, a gasket 7 is provided at the joint between the tooling exhaust pipe 1 and the catalytic muffler tail pipe 2 of the vehicle, and then the tooling exhaust pipe 1 and the catalytic muffler tail pipe 2 of the vehicle are clamped and tightened by a first clamp 8 to ensure a firm and tight connection without air leakage.
[0040] In one embodiment, Figure 2 As shown, the tooling exhaust pipe 1 is connected to the catalytic muffler tail pipe 2 of the vehicle through a high-temperature resistant rubber tube 9, and the connection is tightened using a first clamp 8, so that the installation flexibility is higher and the tooling exhaust pipe 1 can have a certain degree of deflection.
[0041] When the units of the exhaust mass flow rate at the turbine outlet and the mass flow rate of the tooling exhaust pipe 1 are not unified, unit conversion is required, and the conversion formula 1g / s=1 / 1000*3600 (kg / h) is used to uniformly convert them into units of g / s or kg / h.
[0042] In one embodiment, a supporting foot structure 10 is provided at the bottom of the tooling exhaust pipe 1, and the supporting foot structure 10 includes a triangular frame 11 connected to the bottom of the tooling exhaust pipe 1, and springs 12 are respectively provided on both sides of the bottom of the triangular frame 11, and a pad 17 is provided at the bottom of the spring 12. The spring 12 can have a buffering effect to reduce the influence of vibration during vehicle startup on the connection sealing between the tooling exhaust pipe 1 and the catalytic muffler tail pipe 2.
[0043] The triangular frame 11 is connected to the tooling exhaust pipe 1 through a second clamp 13, which facilitates installation and connection.
[0044] Furthermore, a connecting plate 14 is provided at the top of the triangular frame 11, a screw 15 passing downward through the connecting plate 14 is provided at the bottom of the second clamp 13, and nuts 16 for locking the screw 15 are respectively provided on the upper and lower sides of the connecting plate 14. The height of the tooling exhaust pipe 1 can be conveniently adjusted by adjusting the position height of the nut 16 on the screw 15 to adapt to different vehicle heights.
[0045] The above are only preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. A method for detecting air leakage in a vehicle exhaust system, characterized in that: The following steps are involved: Step 1. Make a tool exhaust pipe (1), connect the tool exhaust pipe (1) with the catalytic muffler tail pipe (2) of the vehicle, and ensure that the connection is firm and there is no leakage; the exhaust gas discharged from the catalytic muffler tail pipe (2) flows into the tool exhaust pipe (1), and then is discharged into the atmosphere after passing through the tool exhaust pipe (1); the tool exhaust pipe (1) is equipped with a flow sensor (3), which can detect the mass flow of the gas flowing through the tool exhaust pipe (1), and at the same time send the detected and collected mass flow data to a collection instrument (4) or a computer; Step 2. The acquisition instrument (4) or computer is connected to the OBD communication port (5) of the vehicle via a CAN line, and the turbine outlet exhaust mass flow rate in the ECU parameters of the engine (6) is collected, and the turbine outlet exhaust mass flow rate is aligned with the mass flow rate of the tooling exhaust pipe (1) and then merged to generate a collection file; Step 3. Read the acquisition file and convert the acquisition file into an EXCEL spreadsheet file, draw a time-mass flow curve of the exhaust mass flow at the turbine outlet and the mass flow at the tooling exhaust pipe (1) on the same chart, and obtain a turbine outlet exhaust mass flow curve and a tooling exhaust pipe mass flow curve; Step 4. Compare the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve. If the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve coincide with each other or have a high degree of agreement, it means that there is no air leakage in the exhaust system of the vehicle; if there is an obvious gap between the exhaust mass flow curve at the turbine outlet and the tooling exhaust pipe mass flow curve, and the exhaust mass flow curve at the turbine outlet is higher than the tooling exhaust pipe mass flow curve, it means that there is air leakage in the exhaust system of the vehicle, and each section of the exhaust system needs to be checked in detail.
2. A vehicle exhaust system leakage detection method according to claim 1, characterized in that: The outer diameter of the tooling exhaust pipe (1) is not less than the outer diameter of the catalytic muffler tail pipe (2).
3. A vehicle exhaust system leakage detection method according to claim 1, characterized in that: A gasket (7) is provided at the joint between the tooling exhaust pipe (1) and the catalytic muffler tail pipe (2) of the vehicle.
4. A vehicle exhaust system leakage detection method according to claim 3, characterized in that: The tooling exhaust pipe (1) is clamped and tightened with the catalytic muffler tail pipe (2) of the vehicle via a first clamp (8).
5. A vehicle exhaust system leakage detection method according to claim 1, characterized in that: The tooling exhaust pipe (1) is connected to the catalytic muffler tail pipe (2) of the vehicle via a high temperature resistant rubber tube (9), and the connection is tightened using a first clamp (8).
6. A vehicle exhaust system leakage detection method according to claim 1, characterized in that: When the units of the exhaust mass flow rate at the turbine outlet and the mass flow rate at the tooling exhaust pipe (1) are not unified, unit conversion is required, and the conversion formula 1 (g / s) = 1 / 1000*3600 (kg / h) is used to uniformly convert the units into g / s or kg / h.
7. A vehicle exhaust system leakage detection method according to any one of claims 1 to 6, characterized in that: A supporting foot structure (10) is provided at the bottom of the tooling exhaust pipe (1).
8. A vehicle exhaust system leakage detection method according to claim 7, characterized in that: The support foot structure (10) comprises a triangular frame (11) connected to the bottom of the tooling exhaust pipe (1), springs (12) are respectively provided on both sides of the bottom of the triangular frame (11), and a pad (17) is provided at the bottom of the spring (12).
9. A vehicle exhaust system leakage detection method according to claim 8, characterized in that: The triangular frame (11) is connected to the tooling exhaust pipe (1) via a second clamp (13).
10. A vehicle exhaust system leakage detection method according to claim 9, characterized in that: A connecting plate (14) is provided at the top of the triangular frame (11), a screw rod (15) passing through the connecting plate (14) downward is provided at the bottom of the second clamp (13), and nuts (16) for locking the screw rod (15) are respectively provided at the upper and lower sides of the connecting plate (14).