A Chassis Dynamometer Test Method for Impact Noise in Automotive Transmission Systems Based on Torque Sudden Changes

Abstract

This invention discloses a chassis dynamometer test method for automotive transmission system impact noise based on torque mutation. The method involves: determining vehicle test conditions; conducting a subjective evaluation of transmission system impact noise to obtain impact noise during driving at different speeds and under different operating conditions; determining whether the impact noise meets requirements; if not, conducting objective tests on transmission system impact vibration to obtain transmission system impact vibration data; if requirements are met, the task is terminated; analyzing the transmission system impact vibration data; conducting transmission system impact torque mutation tests; processing the objective torque measurement data; and applying the processed objective torque measurement data results. This invention addresses the problem in existing technologies where stable vehicle speeds cannot be guaranteed for each test, leading to inconsistent test results and relatively large errors when comparing performance and effectiveness across different vehicle models and solutions.

Description

Technical Field

[0001] This invention belongs to the field of automotive technology, specifically relating to a chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation. Background Technology

[0002] For many rear-wheel drive or four-wheel drive vehicles, a "clanging" sound can be heard inside the car when accelerating or decelerating, especially noticeable in the rear seats. This sound is a gear impact noise caused by gear reversal when the gears in the transmission system reverse due to inherent play. Because this is a transient impact noise generated during vehicle operation, it is difficult to ensure vehicle speed stability during road testing, resulting in inconsistent objective test results. Currently, most industry assessments of transmission system transient impact noise levels rely on subjective evaluations conducted on-road. Changan Automobile has disclosed a method for evaluating transient impact noise in automotive transmission systems based on loudness salience. This method involves placing microphones inside the test vehicle to conduct transient impact noise tests on the transmission system under different operating conditions. The collected noise signals are analyzed using loudness calculation methods, and the magnitude of the transient impact noise in the automotive transmission system is evaluated based on the loudness salience. This method can measure objective values ​​that correspond to subjective perceptions. However, for the impact noise problem caused by accelerating or decelerating, the test results vary because the vehicle speed cannot be guaranteed to be stable in each test. The error is relatively large when comparing the level and effect between different vehicle models and different solutions. In addition, this method only proposes one evaluation index for transmission system impact noise, which cannot be used to determine the impact location of the transmission system and is not suitable for the investigation and resolution of transmission system impact problems. Summary of the Invention

[0003] This invention provides a chassis dynamometer test method for impact noise in automotive transmission systems based on torque mutation. It addresses the problems in existing technologies, such as the inability to guarantee stable vehicle speed in each test, resulting in inconsistent test results and relatively large errors when comparing levels and effects between different vehicle models and solutions, as well as the inability to determine the impact location of the transmission system and its unsuitability for troubleshooting and resolving transmission system impact problems.

[0004] This invention is achieved through the following technical solution:

[0005] A chassis dynamometer test method for impact noise in automotive powertrains based on torque mutation, the test method comprising the following steps:

[0006] Step 1: Determine vehicle testing conditions;

[0007] Step 2: Based on the vehicle from Step 1, conduct a subjective evaluation of the transmission system impact noise to obtain the impact noise during driving at different speeds and under different operating conditions;

[0008] Step 3: Determine whether the impact noise during the driving process in Step 2 meets the requirements. If it does not meet the requirements, conduct an objective test of the transmission system impact vibration to obtain the transmission system impact vibration data; if it meets the requirements, end the task.

[0009] Step 4: Analyze the data on the impact vibration of the transmission system obtained in Step 3;

[0010] Step 5: Based on the analysis results of Step 4, perform a test on the sudden change in impact torque of the transmission system;

[0011] Step 6: Based on the test results in Step 5, process the objective torque measurement data;

[0012] Step 7: Apply the results of the objective torque measurement after processing in Step 6.

[0013] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 1 specifically involves fixing the test vehicle onto the chassis dynamometer according to the laboratory operation requirements, selecting a low-noise drum surface to reduce the impact of tire noise on the test, and adjusting the ambient temperature in the test chamber to a specific value, i.e., the room temperature is 25℃.

[0014] After setting up, first set the dynamometer to vehicle-to-vehicle mode to warm up the engine. Drive at 100km / h for 20 minutes to allow the engine coolant temperature to reach above 85℃ and the transmission oil temperature and reducer oil temperature to reach a stable operating temperature range. Then, adjust the chassis dynamometer to vehicle-to-vehicle mode.

[0015] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 2 specifically involves controlling the rotating hub to drag the vehicle to keep the vehicle moving at a constant speed, and subjective evaluators starting the evaluation from a vehicle speed of 10 km / h. After the evaluation at 10 km / h is completed, an evaluation is performed every 5 km / h increase until the vehicle speed reaches 50 km / h.

[0016] At each vehicle speed, subjective evaluators evaluated the impact noise level by rapidly pressing the accelerator pedal at different openings and then quickly releasing it, using a 10-point scoring system.

[0017] After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine speed drops to a stable state. Each evaluation condition should be evaluated at least 6 times, and the final score is the average of all evaluations to determine the impact noise during the acceleration and deceleration of the accelerator pedal.

[0018] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 3 specifically involves first performing a relatively convenient vibration test on the transmission system to confirm whether the impact noise perceived inside the vehicle is transmission system impact noise.

[0019] The three-dimensional vibration sensors are placed at locations where transmission system impact vibration may occur. These locations include the main reducer housing, the center of the left and right wheels, and the intermediate support of the drive shaft. The vibration sensors are connected to a vibration and noise data acquisition device to collect CAN signals of engine speed, transmission gear position, vehicle speed, engine coolant temperature, and transmission oil temperature. Relevant settings are made, and the installation and debugging of the test equipment are completed. The test is performed on the working conditions that the subjective evaluator identifies as problematic. The test method is the same as the subjective evaluation method.

[0020] A chassis dynamometer test system for impact noise of automotive transmission system based on torque mutation, which controls the rotating hub to drag the vehicle to keep the vehicle moving at a constant speed, controls the vehicle speed to start the test from 10 km / h, and after the 10 km / h test is completed, the test is performed every 5 km / h increase until the vehicle speed reaches 50 km / h.

[0021] At each vehicle speed, the test equipment was used to test the impact noise level by rapidly pressing the accelerator pedal at different openings and then quickly releasing it, and the corresponding test data were obtained.

[0022] After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine speed drops back to a stable state. Each operating condition should be tested at least 6 times, and the final test data is the average of all tests to obtain the test data for the operating condition where the subjective evaluator identified the problem.

[0023] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 4 specifically involves processing the peak-to-peak value of the test data at each vibration location after the test, and the peak-to-peak value of the speed is the algebraic difference between the maximum and minimum values ​​at the vibration moment;

[0024] When the peak-to-peak vibration of the main reducer housing is most obvious, step 5 can be directly performed to test the torque of the drive shaft and transmission shaft.

[0025] When the peak value of vibration is most obvious at the center of the left and right wheels or the middle support of the drive shaft, it is caused by an abnormal vehicle condition. The cause of the obvious vibration should be analyzed.

[0026] If there are no obvious vibration peaks in the main reducer housing, the wheel centers of the left and right wheels, and the intermediate support of the drive shaft, then the impact noise inside the vehicle is not the impact noise of the rear transmission system, and other causes should be investigated.

[0027] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 5 specifically involves, when the peak-to-peak vibration of the main reducer housing is most obvious, strain gauges are attached to the drive shaft and transmission shaft for torque testing, and the location of the strain gauge attachment is determined. Simultaneously, vibration of the main reducer and CAN signals are collected. After the test preparation is completed, the problem condition is repeated on the chassis dynamometer.

[0028] A chassis dynamometer test method for impact noise in automotive transmission systems based on torque mutation is disclosed. Specifically, step 6 involves: when an impact occurs in the transmission system, force is transmitted to the connected shaft, causing a torque change. The magnitude of the impact is characterized by the torque mutation. The calculation method involves identifying the maximum torque Tmax at the moment of impact and the torque Tbefoer before the impact, and then calculating the torque mutation ΔT.

[0029] △T=Tmax-Tbefoer.

[0030] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 7 specifically involves determining the impact location of the transmission system, formulating the impact target of the transmission system, and evaluating the effectiveness of the scheme based on the torque measurement results.

[0031] To determine the impact location of the transmission system, if there is a sudden torque change in the transmission shaft but no sudden torque change in the drive shaft, the impact location is determined to be the impact of the large and small gears of the main reducer; if there is a sudden torque change in the drive shaft but no sudden torque change in the transmission shaft, the impact location is determined to be related to the differential gear.

[0032] The formulation of impact targets and the evaluation of scheme effectiveness for the transmission system, combined with subjective evaluation and torque mutation calculation results, establish objective indicators for the transmission system impact noise subsystem. This allows for an objective and effective evaluation of the scheme's effectiveness during the verification and optimization process.

[0033] A chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation is proposed. Based on the torque measurement results, CAE simulation models can also be calibrated. The torque mutation is used as an evaluation index of transmission system impact. A transmission system impact noise simulation model is built, and the accuracy of the model is calibrated based on objective test results, which facilitates the analysis and optimization of impact problems through simulation.

[0034] The beneficial effects of this invention are:

[0035] This invention utilizes a hub motor to drive the vehicle at a constant speed, ensuring that the vehicle speed, engine speed, and other conditions are consistent during each test under the same working conditions. This guarantees the repeatability and comparability of the test, and solves the problem that transmission system impact noise cannot be objectively tested due to poor test consistency.

[0036] This invention provides a method for testing the impact noise of a vehicle's transmission system by using a chassis dynamometer to drive the vehicle's rotating hub. This method ensures that the transmission gears and splines are in a reverse tooth surface meshing state during each test, maximizing the dynamic clearance of the transmission system and increasing the probability of reproducing the impact noise.

[0037] The present invention relates to the fact that the hydraulic damping of the transmission and reducer has a certain impact on the impact noise of the transmission system, and that hydraulic damping is temperature-dependent. Testing on a chassis dynamometer in a laboratory can ensure the consistency of the ambient temperature and avoid the influence of ambient temperature on the test results.

[0038] This invention, by testing the torque of the drive shaft and transmission shaft and calculating the torque mutation, can effectively assess the impact level of the transmission system, determine the impact location, formulate objective impact targets for the transmission system, and calibrate the impact simulation model. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the vibration peak value calculation of the present invention.

[0040] Figure 2 This is a schematic diagram of the bonding position of the torque strain gauge of the present invention.

[0041] Figure 3 This is a schematic diagram illustrating the calculation of torque mutation amount in this invention.

[0042] Figure 4 This is an example diagram of the torque mutation test results of the present invention.

[0043] Figure 5 This is a flowchart of the method of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] A chassis dynamometer test method for impact noise in automotive powertrains based on torque mutation, the test method comprising the following steps:

[0046] Step 1: Determine vehicle testing conditions;

[0047] Step 2: Based on the vehicle from Step 1, conduct a subjective evaluation of the transmission system impact noise to obtain the impact noise during driving at different speeds and under different operating conditions;

[0048] Step 3: Determine whether the impact noise during the driving process in Step 2 meets the requirements. If it does not meet the requirements, conduct an objective test of the transmission system impact vibration to obtain the transmission system impact vibration data; if it meets the requirements, end the task.

[0049] Step 4: Analyze the data on the impact vibration of the transmission system obtained in Step 3;

[0050] Step 5: Based on the analysis results of Step 4, perform a test on the sudden change in impact torque of the transmission system;

[0051] Step 6: Based on the test results in Step 5, process the objective torque measurement data;

[0052] Step 7: Apply the results of the objective torque measurement after processing in Step 6.

[0053] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 1, determining the vehicle test conditions, specifically involves fixing the test vehicle onto the chassis dynamometer according to the laboratory operation requirements, selecting a low-noise drum surface to reduce the impact of tire noise on the test, and adjusting the ambient temperature in the test chamber to a specific value, i.e., the room temperature is 25°C.

[0054] After setting up, first set the dynamometer to vehicle-to-vehicle mode to warm up the engine. Drive at 100km / h for 20 minutes to allow the engine coolant temperature to reach above 85℃ and the transmission oil temperature and reducer oil temperature to reach a stable operating temperature range. Then, adjust the chassis dynamometer to vehicle-to-vehicle mode.

[0055] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 2 is to conduct a subjective evaluation of the impact noise of the transmission system to obtain the impact noise during driving at different speeds and under different operating conditions. Specifically, the vehicle is controlled to be driven by a rotating hub to keep the vehicle moving at a constant speed. The subjective evaluator starts the evaluation from a vehicle speed of 10 km / h. After the evaluation at 10 km / h is completed, an evaluation is conducted every 5 km / h increase until the vehicle speed reaches 50 km / h.

[0056] At each vehicle speed, subjective evaluators rapidly depress the accelerator pedal at different opening degrees (10%, 30%, 50%, 70%, and 100% throttle opening), and then quickly release it to evaluate the impact noise level, using a 10-point scoring system.

[0057] After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine (motor) speed drops to a stable state. Each evaluation condition (vehicle speed 10km / h, throttle opening 10%, vehicle speed 10km / h, throttle opening 30%, vehicle speed 10km / h, throttle opening 50%, vehicle speed 10km / h, throttle opening 70%, vehicle speed 10km / h, throttle opening 100%, vehicle speed 15km / h, throttle opening 10%, vehicle speed 15km / h, throttle opening 30%, etc.) should be evaluated at least 6 times. The final score is the average of all evaluations to determine the impact noise during the acceleration and deceleration conditions while driving.

[0058] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein if step 3 does not meet the requirements, an objective test of transmission system impact vibration is performed to obtain transmission system impact vibration data. Specifically, a relatively convenient vibration test is first performed on the transmission system to confirm whether the impact noise perceived inside the vehicle is transmission system impact noise.

[0059] Three-dimensional vibration sensors are placed at locations where transmission system impact vibrations may occur. These locations include the main reducer housing, the center of the left and right wheels, and the intermediate support of the drive shaft. The vibration sensors are connected to a vibration and noise data acquisition device to collect CAN signals related to the test, such as engine speed, transmission gear position, vehicle speed, engine coolant temperature, and transmission oil temperature. Relevant settings are configured, such as test channel, sensor sensitivity, and sampling frequency. The test equipment is then installed and debugged. Tests are conducted on operating conditions identified as problematic by subjective evaluators, using the same testing method as the subjective evaluation method.

[0060] A chassis dynamometer test system for impact noise of automotive transmission system based on torque mutation, which controls the rotating hub to drag the vehicle to keep the vehicle moving at a constant speed, controls the vehicle speed to start the test from 10 km / h, and after the 10 km / h test is completed, the test is performed every 5 km / h increase until the vehicle speed reaches 50 km / h.

[0061] At each vehicle speed, the test equipment rapidly depresses the accelerator pedal at different openings (10%, 30%, 50%, 70%, and 100% throttle opening), and then quickly releases the pedal to test the impact noise level and obtain the corresponding test data.

[0062] After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine (motor) speed drops to a stable state. Each operating condition (vehicle speed 10km / h, throttle opening 10%, vehicle speed 10km / h, throttle opening 30%, vehicle speed 10km / h, throttle opening 50%, vehicle speed 10km / h, throttle opening 70%, vehicle speed 10km / h, throttle opening 100%, vehicle speed 15km / h, throttle opening 10%, vehicle speed 15km / h, throttle opening 30%, etc.) should be tested at least 6 times. The final test data is the average of all the tests to obtain the test data of the operating condition that the subjective evaluator identified as problematic.

[0063] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 4, analyzing the data of transmission system impact vibration, specifically involves processing the peak-to-peak value of the test data at each vibration location after the test, with the peak-to-peak value at speed being the algebraic difference between the maximum and minimum values ​​at the vibration moment;

[0064] When the peak-to-peak vibration of the main reducer housing is most obvious, step 5 can be directly performed to test the torque of the drive shaft and transmission shaft.

[0065] When the peak value of vibration is most obvious at the center of the left and right wheels or the middle support of the drive shaft, it is generally caused by abnormal vehicle condition. The cause of the obvious vibration should be analyzed.

[0066] If there are no obvious vibration peaks in the main reducer housing, the wheel centers of the left and right wheels, and the intermediate support of the drive shaft, then the impact noise inside the vehicle is not the impact noise of the rear transmission system, and other causes should be investigated.

[0067] A chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation, wherein step 5, testing the transmission system impact torque mutation, specifically involves attaching strain gauges to the drive shaft and transmission shaft to perform torque testing when the peak-to-peak vibration of the main reducer housing is most pronounced. The location of the strain gauges is shown in the schematic diagram. Figure 2 Simultaneously, vibration and CAN signals of the main reducer were collected. After the test preparation was completed, the problem condition was repeated on the chassis dynamometer.

[0068] A chassis dynamometer test method for impact noise in automotive transmission systems based on torque mutation is disclosed. Step 6, processing the objective torque measurement data, specifically involves: when an impact occurs in the transmission system, force is transmitted to the connected shaft, causing a torque change. The magnitude of the impact is characterized by the torque mutation. The calculation method involves identifying the maximum torque Tmax at the moment of impact and the torque Tbefoer before the impact, and then calculating the torque mutation ΔT.

[0069] △T = Tmax - Tbefoer; as Figure 3 As shown.

[0070] A chassis dynamometer test method for impact noise of automotive transmission system based on torque mutation, wherein step 7, applying the torque measurement results, specifically involves determining the impact location of the transmission system, formulating the impact target of the transmission system, and evaluating the effectiveness of the solution based on the torque measurement results.

[0071] To determine the impact location of the transmission system, if there is a sudden torque change in the transmission shaft but no sudden torque change in the drive shaft, the impact location is determined to be the impact of the large and small gears of the main reducer; if there is a sudden torque change in the drive shaft but no sudden torque change in the transmission shaft, the impact location is determined to be related to the differential gear.

[0072] The formulation of impact targets and the evaluation of scheme effectiveness for the transmission system, combined with subjective evaluation and torque mutation calculation results, establish objective indicators for the transmission system impact noise subsystem. This allows for an objective and effective evaluation of the scheme's effectiveness during the verification and optimization process.

[0073] A chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation is proposed. Based on the torque measurement results, CAE simulation models can also be calibrated. The torque mutation is used as an evaluation index of transmission system impact. A transmission system impact noise simulation model is built, and the accuracy of the model is calibrated based on objective test results, which facilitates the analysis and optimization of impact problems through simulation.

[0074] The proposed torque mutation evaluation index can effectively assess the impact level of the transmission system, determine the impact location, formulate objective impact targets for the transmission system, and calibrate the impact simulation model, thereby better solving the problem by combining experimental and simulation methods.

[0075] A method for testing transmission system impact noise by using a chassis dynamometer to tow the vehicle is proposed, which ensures the repeatability and comparability of the transmission system impact noise. This method can be used for both subjective evaluation and objective testing, and solves the problem that transmission system impact noise cannot be objectively tested due to poor test consistency.

[0076] Using a chassis dynamometer to test the impact noise of the transmission system allows the laboratory to maintain a constant temperature, ensuring the consistency of the ambient temperature and reducing the impact of ambient temperature on the test results.

Claims

1. A chassis dynamometer test method for impact noise in automotive transmission systems based on sudden torque changes, characterized in that, The experimental method includes the following steps: Step 1: Determine vehicle testing conditions; Step 2: Based on the vehicle from Step 1, conduct a subjective evaluation of the transmission system impact noise to obtain the impact noise during driving at different speeds and under different operating conditions; Step 3: Determine whether the impact noise during the driving process in Step 2 meets the requirements. If it does not meet the requirements, conduct an objective test of the transmission system impact vibration to obtain the transmission system impact vibration data. If it meets the requirements, end the task. First, conduct a vibration test on the transmission system to confirm whether the impact noise perceived inside the vehicle is transmission system impact noise. Step 4: Analyze the data on the impact vibration of the transmission system obtained in Step 3; Step 4 specifically involves processing the peak-to-peak values ​​of the test data at each vibration location after the test is completed. The peak-to-peak value of the velocity is the algebraic difference between the maximum and minimum values ​​at the vibration moment. When the peak-to-peak vibration of the main reducer housing is most obvious, step 5 can be performed directly to test the torque of the drive shaft and transmission shaft. When the peak value of vibration is most obvious at the center of the left and right wheels or the middle support of the drive shaft, it is caused by an abnormal vehicle condition. Analyze the cause of the obvious vibration location. If there are no obvious vibration peaks in the main reducer housing, the wheel centers of the left and right wheels, and the intermediate support of the drive shaft, then the impact noise inside the vehicle is not the impact noise of the rear transmission system, and other causes should be investigated. Step 5: Based on the analysis results of Step 4, perform a transmission system impact torque mutation test; when the peak-to-peak vibration of the main reducer housing is most obvious, strain gauges are attached to the drive shaft and transmission shaft for torque testing; Step 6: Based on the test results in Step 5, process the objective torque measurement data; Step 7: Apply the objective torque measurement data results processed in Step 6; determine the impact location of the transmission system, formulate the impact target of the transmission system, and evaluate the effectiveness of the solution based on the torque measurement results; The formulation of the transmission system impact target and the evaluation of the scheme effect, combined with subjective evaluation and torque mutation calculation results, formulate objective indicators of the transmission system impact noise subsystem; when verifying the optimization scheme, the effect of the scheme can be objectively and effectively evaluated.

2. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 1, characterized in that, Step 1 specifically involves fixing the test vehicle onto the chassis dynamometer according to the laboratory operating requirements, selecting a low-noise drum surface to reduce the impact of tire noise on the test, and adjusting the ambient temperature in the test chamber to a specific value, i.e., the room temperature is 25°C. After setting up, first set the dynamometer to vehicle-to-vehicle mode to warm up the engine. Drive at 100km / h for 20 minutes to allow the engine coolant temperature to reach above 85℃ and the transmission oil temperature and reducer oil temperature to reach a stable operating temperature range. Then, adjust the chassis dynamometer to vehicle-to-vehicle mode.

3. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 1, characterized in that, Step 2 specifically involves controlling the rotating hub to drag the vehicle so that it maintains a constant speed. The subjective evaluator starts the evaluation from a speed of 10 km / h. After the evaluation at 10 km / h is completed, an evaluation is performed every 5 km / h increase until the speed reaches 50 km / h. At each vehicle speed, subjective evaluators evaluated the impact noise level by rapidly pressing the accelerator pedal at different openings and then quickly releasing it, using a 10-point scoring system. After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine speed drops to a stable state. Each evaluation condition should be evaluated at least 6 times, and the final score is the average of all evaluations to determine the impact noise during the acceleration and deceleration of the accelerator pedal.

4. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 1, characterized in that, Step 3 specifically involves placing a three-dimensional vibration sensor at locations where transmission system impact vibrations may occur. These locations include the main reducer housing, the center of the left and right wheels, and the intermediate support of the drive shaft. The vibration sensor is connected to a vibration and noise data acquisition device, which collects CAN signals for engine speed, transmission gear position, vehicle speed, engine coolant temperature, and transmission oil temperature. Relevant settings are configured, and the installation and debugging of the testing equipment are completed. The test is then conducted on the operating conditions identified as problematic by the subjective evaluators, using the same testing method as the subjective evaluation method.

5. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 4, characterized in that, Control the rotating hub to drag the vehicle to keep the vehicle moving at a constant speed. Start the test with the vehicle speed from 10 km / h. After the 10 km / h test is completed, test again every 5 km / h increase until the vehicle speed reaches 50 km / h. At each vehicle speed, the test equipment was used to test the impact noise level by rapidly pressing the accelerator pedal at different openings and then quickly releasing it, and the corresponding test data were obtained. After each operation, wait 5 seconds before conducting a second evaluation to ensure that the engine speed drops back to a stable state. Each operating condition should be tested at least 6 times, and the final test data is the average of all tests to obtain the test data for the operating condition where the subjective evaluator identified the problem.

6. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 1, characterized in that, Step 5 specifically involves simultaneously collecting vibration and CAN signals from the main reducer. After the test preparation is completed, the problematic operating condition is tested again on the chassis dynamometer.

7. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 1, characterized in that, Step 6 specifically involves the transmission system transmitting force to the connected shaft when an impact occurs, causing a torque change. The magnitude of the impact is characterized by the torque mutation. The calculation method involves identifying the maximum torque Tmax at the moment of impact and the torque Tbefoer before the impact, and then calculating the torque mutation ΔT. △T = Tmax - Tbefoer.

8. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 7, characterized in that, Specifically, step 7 involves determining the impact location of the transmission system. If there is a sudden torque change in the transmission shaft but no sudden torque change in the drive shaft, the impact location is determined to be the impact of the large and small gears of the main reducer. If there is a sudden torque change in the drive shaft but no sudden torque change in the transmission shaft, the impact location is determined to be related to the differential gear.

9. The chassis dynamometer test method for impact noise of automotive transmission systems based on torque mutation as described in claim 8, characterized in that, Based on the torque measurement results, CAE simulation models can also be calibrated. The torque mutation amount can be used as an evaluation index of transmission system impact. A transmission system impact noise simulation model can be built, and the accuracy of the model can be calibrated based on objective test results, which facilitates the analysis and optimization of impact problems through simulation.

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