A method for testing and durability examination of exhaust system vibration frequency

Abstract

The application provides a kind of exhaust system vibration frequency test and endurance test method, the method comprises: exhaust system is arranged according to the whole vehicle arrangement relationship on exciter, vibration frequency test is carried out to exhaust system by exciter;At a preset vibration acceleration, by low to high to exhaust system with a preset speed is scanned vibration, and again from high to low is scanned vibration;The strain value of each preset test position in exhaust system is obtained, the resonance frequency of each preset test position is determined based on the strain value;Resonance vibration is carried out at each resonance frequency, and vibration acceleration is gradually increased until the strain peak value of any preset test position matches the maximum strain value of whole vehicle test;And endurance test evaluation is carried out to exhaust system.The exhaust system is tested and evaluated by the application, which can solve the problem of high cost of exhaust system test and evaluation in the prior art, and the test result does not have too high reference value.

Description

Technical Field

[0001] This invention relates to the field of automotive testing technology, and in particular to a method for testing the vibration frequency and durability of an exhaust system. Background Technology

[0002] As a vehicle's exhaust gas treatment device, a reliable exhaust system is not only a design requirement for OEMs but also a necessity for environmental protection, carbon neutrality, and carbon peaking. The engine is a vibration source, and its connected accessories are also affected, generating vibrations. If the exhaust system is poorly designed, its vibration frequency coupled with the engine's vibration frequency can cause resonance or excite maximum strain. Therefore, determining the vibration frequency of the exhaust system is essential, and durability verification is necessary to ensure its compliance.

[0003] In the existing technology, the testing and evaluation of exhaust systems are generally carried out by building an engine test bench, setting up the engine and accessories on the engine vibration test bench laboratory, performing a full-speed frequency sweep, selecting the point with the largest vibration amplitude, and applying the test.

[0004] However, the testing and evaluation of the exhaust system in the existing technology requires the construction of an engine test bench, which is costly in terms of hardware. At the same time, it needs to be carried out in a dedicated engine durability test bench, which is also costly in terms of testing. In addition, since the frequency points obtained by sweeping the engine test bench are coupling points, not the inherent frequency points of the exhaust system itself, vibration at this frequency point is not the most stringent operating condition and does not have high reference value. Summary of the Invention

[0005] Based on this, the purpose of the present invention is to provide a method for testing the vibration frequency and durability of an exhaust system, which aims to solve the shortcomings of the prior art in that the testing and assessment of exhaust systems is costly and the test results do not have high reference value.

[0006] To achieve the above objectives, the present invention provides a method for testing the vibration frequency and durability of an exhaust system, the method comprising:

[0007] An exhaust system is provided, and strain gauges are attached to preset test positions of the exhaust system to obtain strain data of the strain gauges during road testing.

[0008] The exhaust system is arranged on the vibrator according to the overall vehicle layout, and the vibration frequency of the exhaust system is tested by the vibrator.

[0009] Under a preset vibration acceleration, the exhaust system is scanned and vibrated from low to high at a preset speed, and then scanned and vibrated from high to low again;

[0010] acquiring strain values of each preset examination position of the exhaust system, and determining resonance frequencies of each preset examination position based on the strain values;

[0011] resonant vibration is performed at each resonance frequency, and vibration acceleration is gradually increased until the strain peak value of any preset examination position matches the maximum strain value of the whole vehicle test;

[0012] When the frequency point of the vibration acceleration matches the strain of the preset examination position of the whole vehicle part well, the vibration acceleration is determined as an input value for durability examination to perform durability examination and evaluation.

[0013] According to an aspect of the above technical solution, an exhaust system is provided, and a strain gauge is attached to a preset examination position of the exhaust system. In the step of acquiring strain data of the strain gauge in road testing, the step specifically includes:

[0014] An exhaust system is provided, and a strain gauge is attached to a preset examination position of the exhaust system. The preset examination position at least includes each weld position and hook position in the exhaust system.

[0015] In the whole vehicle road testing, strain data of each weld position and hook position in the exhaust system is acquired.

[0016] According to an aspect of the above technical solution, the exhaust system is arranged on the exciter according to the whole vehicle arrangement relationship. In the step of performing vibration frequency test on the exhaust system by the exciter, the step specifically includes:

[0017] An exciter is provided.

[0018] The exhaust system is arranged on the exciter according to the whole vehicle arrangement relationship.

[0019] The exhaust system is tested for vibration frequency by the exciter.

[0020] According to an aspect of the above technical solution, in the step of scanning vibration of the exhaust system from low to high at a preset vibration acceleration and scanning vibration from high to low again at a preset speed, the preset vibration acceleration is 2g, the preset speed is 0.6 Hz / s, and the scanning is linear from 20Hz to 200Hz at the speed of 0.6 Hz / s and from 200Hz to 20Hz at the speed of 0.6 Hz / s.

[0021] According to an aspect of the above technical solution, in the step of acquiring strain values of each preset examination position of the exhaust system and determining resonance frequencies of each preset examination position based on the strain values, the step specifically includes:

[0022] acquiring strain values of each weld position and hook position in the exhaust system when the exhaust system is tested by the exciter;

[0023] determining resonance frequencies of each weld position and hook position by strain FSD diagram based on the strain values of each weld position and hook position in the exhaust system.

[0024] According to an aspect of the above technical solution, the step of performing stationary vibration at each resonance frequency and gradually increasing the vibration acceleration until the strain peak value of any of the preset evaluation positions matches the maximum strain value of the whole vehicle test specifically includes:

[0025] performing stationary vibration at each resonance frequency and gradually increasing the vibration acceleration by a preset increment;

[0026] until the strain peak value of a certain preset evaluation position matches the maximum strain value level of the whole vehicle test;

[0027] ending the vibration frequency test of the exhaust system.

[0028] According to an aspect of the above technical solution, in the step of determining the input value of the durability evaluation as the vibration acceleration when the frequency point of the vibration acceleration matches the strain of the preset evaluation positions of the whole vehicle well, the vibration working condition of the durability evaluation is 30000 times.

[0029] According to an aspect of the above technical solution, the index of the durability evaluation further includes:

[0030] whether each preset evaluation position has a crack, and whether the maximum torque drop of each component in the exhaust system is within 20%.

[0031] Compared with the prior art, the exhaust system vibration frequency test and durability evaluation method has at least the following beneficial effects:

[0032] 1. The whole process of testing and evaluating the exhaust system does not require high-value parts such as engines;

[0033] 2. It does not need to build a responsible engine bench;

[0034] 3. The sweep frequency point covers the engine excitation frequency, which can perfectly replace the engine sweep frequency and the test data conforms to the actual whole vehicle tuning, and the test result is more reliable;

[0035] 4. The test cost is low and easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1A flowchart of a method for testing and durability examination of vibration frequency of an exhaust system in the first embodiment of the present application is shown in FIG. 1.

[0037] Figure 2 A scanning frequency diagram for testing vibration frequency of an exhaust system in the first embodiment of the present application is shown in FIG. 2.

[0038] Figure 3 A resonance frequency diagram for testing vibration frequency of an exhaust system in the first embodiment of the present application is shown in FIG. 3.

[0039] The following detailed description will further illustrate the present application with reference to the above-mentioned drawings. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. Several embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0041] Embodiment One

[0042] Referring to Figures 1-3 , the first embodiment of the present application provides a method for testing and durability examination of vibration frequency of an exhaust system, referring to Figure 1 , the method comprises steps S10-S60:

[0043] Step S10, providing an exhaust system, pasting strain gauges at preset examination positions of the exhaust system, and obtaining strain data of the strain gauges in road testing;

[0044] Step S20, arranging the exhaust system according to the arrangement relationship of the whole vehicle on an exciter, and testing vibration frequency of the exhaust system by the exciter;

[0045] Step S30, scanning vibration of the exhaust system from low to high at a preset vibration acceleration and a preset speed, and again scanning vibration from high to low;

[0046] Step S40, obtaining strain values of each preset examination position of the exhaust system, and determining resonance frequencies of each preset examination position based on the strain values;

[0047] Step S50, performing dwell vibration at each resonance frequency, and gradually increasing vibration acceleration until the strain peak value of any preset examination position matches the maximum strain value of the whole vehicle test;

[0048] Step S60, and when a frequency point of the vibration acceleration matches well with the strain of the preset examination position of the vehicle part, the vibration acceleration is determined as an input value for the durability examination to perform the durability examination evaluation.

[0049] In the embodiment, the exhaust system is provided with strain gauges at preset examination positions, and the step of obtaining strain data of the strain gauges in road testing specifically includes:

[0050] The exhaust system is provided with strain gauges at preset examination positions, and the preset examination positions at least include positions of welds and hangers in the exhaust system.

[0051] In the road testing of the vehicle, strain data of the positions of the welds and the hangers in the exhaust system are obtained.

[0052] In the embodiment, the exhaust system is arranged on the exciter according to the arrangement relationship of the vehicle, and the step of performing vibration frequency testing on the exhaust system by the exciter specifically includes:

[0053] The exciter is provided.

[0054] The exhaust system is arranged on the exciter according to the arrangement relationship of the vehicle.

[0055] The exhaust system is tested by the exciter.

[0056] In the embodiment, the exhaust system is scanned and vibrated from low to high at a preset speed under a preset vibration acceleration, and then scanned and vibrated from high to low again, the preset vibration acceleration is 2g, the preset speed is 0.6 Hz / s, and the speed is linearly scanned from 20 Hz to 200 Hz at 0.6 Hz / s, and then linearly scanned from 200 Hz to 20 Hz at 0.6 Hz / s.

[0057] In the embodiment, the strain values of the preset examination positions in the exhaust system are obtained, and the step of determining the resonance frequencies of the preset examination positions based on the strain values specifically includes:

[0058] When the exhaust system is tested by the exciter, the strain values of the positions of the welds and the hangers in the exhaust system are obtained.

[0059] Based on the strain values of the positions of the welds and the hangers in the exhaust system, the resonance frequencies of the positions of the welds and the hangers are determined by the strain FSD diagram.

[0060] In the embodiment, the step of performing the dwell vibration at each resonance frequency and gradually increasing the vibration acceleration until the strain peak value of any of the preset examination positions matches the maximum strain value of the whole vehicle test specifically includes:

[0061] performing the dwell vibration at each resonance frequency and gradually increasing the vibration acceleration by a preset increment;

[0062] until the strain peak value of a certain preset examination position matches the maximum strain value level of the whole vehicle test;

[0063] ending the vibration frequency test of the exhaust system.

[0064] In the embodiment, when a frequency point of the vibration acceleration matches the strain of the whole vehicle part preset examination position well, the vibration acceleration is determined as the input value of the durability examination to perform the step of durability examination and evaluation, and the vibration working condition of the durability examination and evaluation is 30000 times.

[0065] In the embodiment, the index of the durability examination and evaluation further includes:

[0066] whether each preset examination position has a crack, and whether the torque drop of each component in the exhaust system is within 20%.

[0067] The exhaust system vibration frequency test and durability examination method shown in the embodiment specifically has at least the following requirements when performing the vibration frequency test on the exhaust system:

[0068] 1) The shaft of the engine vibration treatment device matches the power line shaft of the engine.

[0069] 2) The exhaust pipe is arranged in the vibration treatment device according to the actual arrangement of the vehicle.

[0070] 3) Each tightening part of the exhaust system is tightened.

[0071] 4) The detection is performed according to the following conditions:

[0072] Road vibration condition - frequency: actual vehicle stress or peak frequency of actual vehicle stress

[0073] Amplitude: adjust the amplitude to reproduce the actual vehicle stress for 300000 times.

[0074] Frequency: linear scanning vibration

[0075] Amplitude: adjust the amplitude to match the maximum stress in the linear scanning and the maximum stress of the actual vehicle

[0076] 5) Check the crack and looseness of each part at any time interval.

[0077] Compared with the prior art, the exhaust system vibration frequency test and durability test method shown in the application has at least the following beneficial effects:

[0078] 1. The entire process of testing and testing the exhaust system does not require high-value parts such as engines;

[0079] 2. No responsible engine bench needs to be built;

[0080] 3. The sweep frequency point covers the engine excitation frequency, which can perfectly replace the engine sweep frequency and the test data conforms to the actual vehicle tuning, and the test result is more reliable;

[0081] 4. The test cost is low and easy to implement.

[0082] Those skilled in the art can understand that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a list of executable instructions for implementing the logic function, which can be embodied in any computer readable medium for use by an instruction execution system, device or equipment (such as a computer-based system, a system including a processor or other system that can fetch and execute instructions from the instruction execution system, device or equipment) or in conjunction with these instructions execution system, device or equipment.

[0083] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0084] The above-described embodiments only express several implementation manners of the present application, which are described in a more specific and detailed manner, but should not be understood as limiting the scope of the present application. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the protection scope of the present application. Therefore, the protection scope of the present application patent should be subject to the appended claims.

Claims

1. A method for testing and durability examination of exhaust system vibration frequency, characterized in that, The method comprises: providing an exhaust system, pasting strain gauges at preset test positions of the exhaust system, and obtaining strain data of the strain gauges in road testing; arranging the exhaust system on a shaker according to the arrangement relationship of the whole vehicle, and testing the vibration frequency of the exhaust system by the shaker; scanning and vibrating the exhaust system from low to high at a preset vibration acceleration, and then scanning and vibrating from high to low; obtaining the strain values of each preset test position of the exhaust system, and determining the resonance frequencies of each preset test position based on the strain values; carrying out dwell vibration at each resonance frequency, and gradually increasing the vibration acceleration until the strain peak value of any preset test position matches the maximum strain value in the whole vehicle test; and when the strain peak value of the preset test position in the bench test matches the maximum strain value obtained in the whole vehicle test by gradually increasing the vibration acceleration at a certain resonance frequency, the vibration acceleration applied at this time and the corresponding resonance frequency are determined as the input condition of the durability test for carrying out the durability test evaluation; wherein the step of providing an exhaust system, pasting strain gauges at preset test positions of the exhaust system, and obtaining strain data of the strain gauges in road testing specifically comprises: providing an exhaust system, and pasting strain gauges at preset test positions of the exhaust system, wherein the preset test positions at least include each weld position and hook position in the exhaust system; obtaining strain data of each weld position and hook position in the exhaust system in whole vehicle road testing; wherein the step of arranging the exhaust system on a shaker according to the arrangement relationship of the whole vehicle, and testing the vibration frequency of the exhaust system by the shaker specifically comprises: providing a shaker; arranging the exhaust system on the shaker according to the arrangement relationship of the whole vehicle; testing the vibration frequency of the exhaust system by the shaker; wherein the step of obtaining the strain values of each preset test position of the exhaust system, and determining the resonance frequencies of each preset test position based on the strain values specifically comprises: obtaining the strain values of each weld position and hook position in the exhaust system when testing the vibration of the exhaust system by the shaker; determining the resonance frequencies of each weld position and hook position by strain FSD diagram based on the strain values of each weld position and hook position in the exhaust system; wherein the step of carrying out dwell vibration at each resonance frequency, and gradually increasing the vibration acceleration until the strain peak value of any preset test position matches the maximum strain value in the whole vehicle test specifically comprises: carrying out dwell vibration at each resonance frequency, and gradually increasing the vibration acceleration by a preset increment; until the strain peak value of a certain preset test position matches the maximum strain value level in the whole vehicle test; ending the vibration frequency test of the exhaust system.

2. The exhaust system vibration frequency test and durability evaluation method according to claim 1, characterized by, In the step of scanning vibration of the exhaust system from low to high at a preset vibration acceleration and again from high to low, the preset vibration acceleration is 2g, the preset speed is 0.6 Hz / s, and the speed is linearly scanned from 20 Hz to 200 Hz at 0.6 Hz / s and then linearly scanned from 200 Hz to 20 Hz at 0.6 Hz / s.

3. The exhaust system vibration frequency test and durability evaluation method according to claim 1, characterized by, In the step of determining the vibration acceleration as the input value for durability evaluation when the frequency point of the vibration acceleration matches well with the strain of the preset examination position of the vehicle part, the vibration working condition for the durability evaluation is 30000 times.

4. The exhaust system vibration frequency test and durability evaluation method according to any one of claims 1 to 3, characterized by, The index for the durability evaluation further includes: Whether each preset examination position has a crack, and the maximum torque drop of each component in the exhaust system is within 20%.

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