Method for analyzing and optimizing clunk impact of automobile driveline

Abstract

The application discloses a kind of automobile drive train Clunk impact sound analysis optimization method, comprising the following steps: S1, the NVH test data of vehicle is obtained and actual impact time, obtain the design parameter and actual structure parameter of drive train component;S2, establish drive train simulation analysis model, and calibrate drive train simulation analysis model, obtain simulation impact time according to calibrated drive train simulation analysis model;S3, whether actual impact time and simulation impact time coincide is evaluated;S4, the parameter of drive train simulation analysis model is adjusted, impact sensitivity analysis is carried out to various parameters, and theoretical optimization scheme is formulated;S5, based on theoretical optimization scheme, sample piece is made and NVH verification and effect evaluation are carried out.The application is analyzed and scheme is explored by using simulation combined with test means, reduces the sample piece production of pure test and reduces trial and error cost, greatly shortens the problem solving cycle, and more accurately solves the problem.

Description

Technical Field

[0001] This invention relates to the field of automotive NVH technology, specifically to a method for analyzing and optimizing the impact sound of a car's drivetrain. Background Technology

[0002] Clunk impact noise (also known as metallic knocking noise) under Tip-in (rapid acceleration) and Tip-out (rapid deceleration) conditions is a phenomenon in which the automotive transmission system responds to the impact excitation of sudden torque reversal. It is characterized by irregular, random, and momentary short-lived abnormal broadband noise (0.3K~5KHz) of metallic knocking. It is a common NVH (Noise, Vibration, Harshness) and drivability problem in both traditional fuel vehicles and new energy electric vehicles.

[0003] When there are sudden torque changes or reverse torque in the vehicle's drivetrain, impacts will occur between the positive and negative contact surfaces due to the clearance in the gear pairs or other transmission contact pairs. The collision excitation energy between components will either directly radiate sound or excite the surface vibration of structural components along the vibration transmission path, thus driving the air to radiate sound. According to the mechanism analysis, a clang impact sound will only occur when the following two conditions are met: 1. Reversal of the driving torque, from negative to positive (Tip in) or from positive to negative (Tip out); 2. Sufficient clearance in the transmission system. Currently, the solution to clang impact sounds in automotive drivetrains mainly addresses the source: a gentler slope of the torque curve at the "zero torque point" when there is clearance can reduce the degree of torque change, thereby reducing the impact force; reducing the transmission clearance will reduce the energy during the impact, thus reducing the impact force.

[0004] However, automotive drivetrains have numerous contact pairs, such as gear backlash, spline and sleeve backlash, sleeve and hub spline backlash, hub and shaft spline backlash, differential half-gear and half-shaft angular clearance, differential and drive shaft spline backlash, and drive shaft circumferential clearance. All of these clearances can potentially be sources of impact noise. Since the drivetrain is a highly integrated and precisely fitted component, identifying the maximum impact noise source among so many contact pairs presents a significant engineering challenge. Conventional methods involve clearance calibration or trial and error, which are tedious and offer limited guidance. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a method for analyzing and optimizing the impact sound of a Clunk in an automotive transmission system. By using simulation combined with experiments to analyze the causes and explore solutions, the invention reduces the need for pure experimental prototype manufacturing and lowers the cost of trial and error, significantly shortening the problem-solving cycle and solving the problem more accurately.

[0006] The present invention provides a method for analyzing and optimizing the impact sound of a car drivetrain cluster, comprising the following steps:

[0007] S1. Obtain the vehicle's NVH test data and actual impact time, and obtain the design parameters and actual structural parameters of the transmission system components;

[0008] S2. Based on the design parameters and actual structural parameters, establish a simulation analysis model of the transmission system, and calibrate the simulation analysis model of the transmission system based on NVH test data. Obtain the simulated impact time based on the calibrated simulation analysis model of the transmission system.

[0009] S3. Evaluate whether the actual impact time matches the simulated impact time. If yes, proceed to step S4. If no, calibrate and adjust the transmission system simulation analysis model until the actual impact time matches the simulated impact time.

[0010] S4. Adjust the parameters of the transmission system simulation analysis model, perform impact sensitivity analysis on various parameters, and formulate a theoretical optimization scheme.

[0011] S5. Based on the theoretical optimization scheme, produce prototypes and conduct NVH verification and effect evaluation.

[0012] further,

[0013] Step S1 includes the following steps:

[0014] S11. Perform NVH testing and obtain NVH test data; and simultaneously collect electronic fuel injection signal data;

[0015] S12. Based on NVH test data and electronic fuel injection signal data, compare the vehicle operating condition information to determine the actual impact time of the impact sound.

[0016] S13. Obtain the design parameters of the transmission system components and perform precise measurements on the dimensions of the transmission system components to obtain the actual structural parameters of the transmission system components. The actual structural parameters include the actual precise measured dimensions of each transmission system component and the fit clearance of each contact pair in the transmission system.

[0017] further,

[0018] In step S11, the NVH test includes: placing vibration sensors on the vehicle's transmission housing, transmission mount active / passive ends, differential, and wheel hubs, and conducting a Clunk impact sound test on the vehicle under Tip in / out conditions.

[0019] further,

[0020] In step S12, the vehicle operating condition information includes: accelerator pedal depth, throttle opening, gear position, vibration, engine speed, A / B shaft speed, engine torque, friction torque, clutch pressure, and vehicle speed information.

[0021] further,

[0022] In step S13, the transmission system components include: transmission system flywheel clutch spline, gear shift gear, main reduction gear, differential half-shaft spline, half-shaft sliding joint, and half-shaft fixed joint; the mating clearances of each contact pair in the transmission system include: gear backlash, gear sleeve backlash, gear sleeve and hub spline backlash, hub and shaft spline backlash, differential half-shaft angular clearance, differential and transmission shaft spline backlash, and drive shaft circumferential clearance.

[0023] further,

[0024] Step S2 includes the following steps:

[0025] S21. Establish a simulation analysis model of the transmission system based on the design parameters and actual structural parameters; the design parameters include the DMF primary inertia, the DMF secondary inertia, the K0 clutch friction plate inertia, and the motor rotor support inertia.

[0026] S22. Using the test results obtained from NVH testing, the transmission system simulation analysis model is reverse-calibrated, and the parameters of the transmission system simulation analysis model are adjusted.

[0027] S23. Based on the calibrated transmission system simulation analysis model, perform simulation analysis of the impact moment to obtain the simulated impact moment.

[0028] further,

[0029] Step S4 includes the following steps:

[0030] S41. Based on the simulation analysis model of the transmission system, analyze the force situation of each contact pair in the transmission system and obtain the force situation of each contact pair.

[0031] S42. Based on the simulation analysis model of the transmission system, obtain the impact power of each contact pair and determine the contact pair with the largest sound source generated by the impact sound.

[0032] S43. Adjust the fit clearance of a single contact pair in the transmission system simulation analysis model, compare the changes in impact power before and after the adjustment, and obtain the interactive effects of the gap changes of each contact pair on its own impact power and the impact power of other positions.

[0033] S44. In the simulation analysis model of the transmission system, change the damping, inertia and stiffness of the transmission system components, compare the changes in impact power before and after the adjustment, and obtain the influence of the damping, inertia and stiffness of the transmission system components on the impact power.

[0034] S45. Based on the simulation analysis results of steps S42-S44, formulate a theoretical optimization scheme.

[0035] further,

[0036] In step S42, the impact power of each contact pair is obtained by inputting a sudden torque change to the transmission system simulation analysis model to simulate Tip in / out, and calculating the impact power of the contact pair by using the impact force F and displacement S output at the gap of each contact pair. ,in It refers to the derivative of displacement S, and V refers to the relative velocity of the impact between the contact pairs.

[0037] further,

[0038] Step S5 includes the following steps:

[0039] S51. Based on the theoretical optimization scheme formulated in step S45, produce a physical prototype;

[0040] S52. Conduct NVH testing on the vehicle with the optimized sample replaced, and simultaneously collect electronic fuel injection signal data. Based on the NVH test data and electronic fuel injection signal data, compare the vehicle operating condition information to determine the actual vibration energy level and actual impact time of the impact sound.

[0041] S53. Conduct NVH verification and effectiveness evaluation.

[0042] further,

[0043] Step S53 includes: comparing the NVH test data, EFI signal data, actual vibration energy level and actual impact time obtained in step S52 with the NVH test data, EFI signal data, actual vibration energy level and actual impact time obtained in step S12, and evaluating the effectiveness of the theoretical optimization scheme.

[0044] The beneficial effects of this invention are as follows: By employing simulation combined with experimentation for cause analysis and solution exploration, this invention reduces the need for pure experimental prototype manufacturing and lowers trial-and-error costs, significantly shortening the problem-solving cycle and more accurately addressing the issues. It calibrates the simulation model using NVH test data and verifies it with actual impact moments, ensuring the model's reliability. It uses component design parameters and actual structural parameters for simulation modeling, combining theory with practice to ensure the effectiveness of simulation results and solutions. Using impact power to measure impact provides a better reflection of auditory perception and more closely aligns with actual complaint points. Impact sensitivity analysis of various parameters provides a theoretical basis for solution formulation, and the control of multiple parameters makes engineering implementation easier. Attached Figure Description

[0045] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0046] Figure 1 This is a flowchart illustrating the Clunk impact sound analysis and optimization method for the automotive powertrain in this embodiment.

[0047] Figure 2 This is a flowchart illustrating a further detail of step S1 in this embodiment;

[0048] Figure 3 This is a schematic diagram of the vibration sensor arrangement in step S11 of this embodiment;

[0049] Figure 4 This is a graph showing the NVH test data results (before optimization) in step S12 of this embodiment.

[0050] Figure 5 This is a flowchart illustrating a further detail of step S2 in this embodiment;

[0051] Figure 6 This is a schematic diagram of the impact moment analysis results in this embodiment;

[0052] Figure 7 This is a flowchart illustrating a further detail of step S4 in this embodiment;

[0053] Figure 8 This is a schematic diagram showing the analysis results of the impact force at each gap in this embodiment;

[0054] Figure 9 This is a schematic diagram showing the impact power calculation results for each contact pair in this embodiment;

[0055] Figure 10 This is a schematic diagram showing the sensitivity analysis results of the gaps between each contact pair in this embodiment;

[0056] Figure 11Schemes 1 and 2 in the diagram show the results of the analysis of the impact power of changing the damping, inertia and stiffness of the transmission system components.

[0057] Figure 12 This is a flowchart illustrating a further detail of step S5 in this embodiment;

[0058] Figure 13 This is a graph showing the test data results (optimized) for step S53 of this embodiment. Detailed Implementation

[0059] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0060] like Figure 1 As shown in this embodiment, a method for analyzing and optimizing the impact sound of a car drivetrain cluster includes the following steps:

[0061] S1. Obtain the vehicle's NVH test data and actual impact time, and obtain the design parameters and actual structural parameters of the transmission system components; the design parameters and actual structural parameters can provide data support for establishing the transmission system simulation analysis model, and the NVH test data can be used to calibrate the transmission system simulation analysis model in the future to ensure the reliability of the model;

[0062] S2. Simultaneously, based on design parameters and actual structural parameters, a transmission system simulation analysis model is established, and the transmission system simulation analysis model is calibrated based on NVH test data. The simulated impact time is obtained based on the calibrated transmission system simulation analysis model.

[0063] S3. Evaluate whether the actual impact time matches the simulated impact time. If yes, proceed to step S4. If no, calibrate and adjust the transmission system simulation analysis model until the actual impact time matches the simulated impact time. Use the actual impact time to verify the simulated impact time to ensure the reliability of the model.

[0064] S4. Adjust the parameters of the transmission system simulation analysis model, perform impact sensitivity analysis on various parameters, and formulate theoretical optimization schemes; perform impact sensitivity analysis on various parameters to provide a theoretical basis for the formulation of the scheme, and the control of multiple parameters makes it easier to implement in engineering.

[0065] S5. Based on the theoretical optimization scheme, prototypes were fabricated and NVH verification and effect evaluation were conducted. By using simulation combined with experiments for cause analysis and solution exploration, the number of prototypes fabricated for pure experiments was reduced, and the cost of trial and error was lowered, significantly shortening the problem-solving cycle and solving problems more accurately.

[0066] In this embodiment,

[0067] like Figure 2As shown, step S1 includes the following steps:

[0068] S11. Conduct NVH testing and acquire NVH test data; simultaneously collect electronic fuel injection signal data; specifically, NVH testing includes: placing vibration sensors on the vehicle's transmission housing, transmission mounts (active / passive ends), differential, and wheel hubs to conduct a Clunk impact sound test under Tip-in / out conditions. Specifically, such as... Figure 3 As shown, vibration sensors A are installed on the transmission housing, B, C, and D on the transmission mounts (both active and passive ends), E and F on the differential, and G and H on the two wheel hubs, for a total of eight sensors. After installation, the connection to the NVH testing equipment was confirmed to be normal. Preparations were made for simultaneous acquisition of electronic fuel injection data, and the signals were tested to ensure they were normal. Objective testing was then conducted once the conditions were met. Ten sets of tests were performed. Different operations may not necessarily reproduce the problem, and the tests also allowed observation of whether the impact pattern was uniform and the measurement of the maximum and average impact energy. Impact noise is generated by vibration, and the "clunk" impact sound is actually a combined perception of sound and vibration; therefore, the impact energy can be measured by the vibration data obtained from the sensors.

[0069] S12. Based on NVH test data and electronic fuel injection signal data, compare with vehicle operating condition information to determine the actual impact time of the impact sound; the vehicle operating condition information includes: accelerator pedal depth, throttle opening, gear position, vibration, engine speed, A / B shaft speed, engine torque, friction torque, clutch pressure, and vehicle speed information. Figure 4 The schematic diagram of the NVH test results shows that the maximum impact vibration amplitude of the Clunk is Figure 4 The vibration of the left suspension mounting point is 21g (vertical axis), and the maximum vibration of the left suspension mounting point occurs at 21.47 seconds (horizontal axis). The tester's subjective evaluation is 5.5 points.

[0070] S13. Obtain the design parameters of the transmission system components and perform precise measurements on the dimensions of the transmission system components to obtain the actual structural parameters of the transmission system components. The actual structural parameters include the actual precisely measured dimensions of each transmission system component and the fit clearance of each contact pair in the transmission system. The transmission system components include: transmission system flywheel clutch spline, gear shift gear, main reduction gear, differential half-shaft spline, half-shaft sliding joint, and half-shaft fixed joint. The fit clearance of each contact pair in the transmission system includes: gear backlash, engagement tooth spline and gear sleeve backlash, gear sleeve and gear hub spline backlash, gear hub and shaft spline backlash, differential half-gear half-shaft angular clearance, differential and drive shaft spline backlash, and drive shaft circumferential clearance.

[0071] In this embodiment,

[0072] like Figure 5 As shown, step S2 includes the following steps:

[0073] S21. Establish a simulation analysis model of the transmission system based on the design parameters and actual structural parameters; the design parameters include the DMF primary inertia, the DMF secondary inertia, the K0 clutch friction plate inertia, and the motor rotor support inertia.

[0074] S22. Using the test results obtained from NVH testing, the transmission system simulation analysis model is reverse-calibrated, and the parameters of the transmission system simulation analysis model are adjusted.

[0075] S23. Based on the calibrated transmission system simulation analysis model, perform simulation analysis of the impact moment to obtain the simulated impact moment. Figure 6 This is a schematic diagram of the impact moment analysis results in this embodiment. It can obtain the simulated impact moment, number of impacts, and impact power of the flywheel clutch spline, gear, main reduction gear, differential half-shaft spline, half-shaft moving joint, half-shaft fixed joint, etc. in the transmission system simulation analysis model, as well as which impact has the greatest energy.

[0076] In this embodiment,

[0077] like Figure 7 As shown, step S4 includes the following steps:

[0078] S41. Based on the transmission system simulation analysis model, analyze the force conditions of each contact pair in the transmission system and obtain the force conditions of each contact pair; by inputting the sudden torque simulation Tip in / out into the transmission system simulation analysis model, obtain the impact force F and displacement S output at the gap of each contact pair, and provide data support for subsequent judgment of the impact source. Figure 8 This is a schematic diagram of the impact force analysis results of each gap in this embodiment. As can be seen from the figure, the spline has the greatest force, followed by the half-shaft fixed joint. In addition to the spline, the further back the gap is, the greater the impact force.

[0079] S42. Based on the simulation analysis model of the transmission system, the impact power of each contact pair is obtained, and the contact pair with the largest sound source generated by the impact sound is determined. Impact power is a quantity that best reflects auditory perception and is more in line with human perception than impact force, so it is more reasonable to use impact power for analysis. Figure 9 This diagram illustrates the calculated impact power of each contact pair in this embodiment. The impact power is highest at the gap between the half-shaft fixed sections, thus identifying the maximum sound source in this embodiment as the gap between the half-shaft fixed sections. The impact power of each contact pair is obtained by inputting a sudden torque change (Tip in / out) into the transmission system simulation analysis model, and calculating the impact power of that contact pair using the impact force F and displacement S output at the gap of each contact pair obtained in step S41. ,in It refers to the derivative of displacement S, and V refers to the relative velocity of the impact between the contact pairs.

[0080] S43. Adjust the fit clearance of a single contact pair in the transmission system simulation analysis model, compare the changes in impact power before and after the adjustment, and obtain the interactive effects of the gap changes of each contact pair on its own impact power and the impact power of other positions. Figure 10 This diagram illustrates the sensitivity analysis results of the gaps between various contact pairs in this embodiment, including the interactive effects of gap changes on their own impact power and on the impact power at other locations. Subsequent engineering solutions can be developed based on these results. Figure 9 It can be seen that the reduction in clearance of the differential half-shaft spline, half-shaft sliding joint, and half-shaft fixed joint in this embodiment is beneficial to the half-shaft fixed joint where the impact power is the greatest; the reduction in clearance of the flywheel clutch spline, gear, and main reduction gear is only beneficial to itself, and the reduction in clearance of the main reduction gear is also detrimental to the half-shaft sliding joint.

[0081] S44. In the simulation analysis model of the transmission system, change the damping, inertia and stiffness of the transmission system components, compare the changes in impact power before and after the adjustment, and obtain the influence of the damping, inertia and stiffness of the transmission system components on the impact power. Figure 11 Schemes 1 and 2 in the diagram show the results of the analysis of the impact power of changing the damping, inertia and stiffness of the transmission system components. This shows that not only the gap affects the impact, but also the inertia and stiffness before and after the gap. In the optimization of projects where the Clunk impact sound problem occurs, other parameters besides the gap should be considered in the optimization of the scheme.

[0082] S45. Based on the simulation analysis results of steps S42-S44, formulate theoretical optimization schemes. Multiple different theoretical optimization schemes can be formulated through simulation of the transmission system simulation analysis model.

[0083] In this embodiment, as Figure 12 As shown, step S5 includes the following steps:

[0084] S51. Based on the theoretical optimization scheme formulated in step S45, produce physical prototypes; multiple different theoretical optimization schemes can be formulated in step S45, and corresponding physical prototypes for multiple schemes can be formulated accordingly.

[0085] S52. Conduct NVH testing on the vehicle with the optimized sample replaced, and simultaneously collect electronic fuel injection signal data. Based on the NVH test data and electronic fuel injection signal data, compare the vehicle operating condition information to determine the actual vibration energy level and actual impact time of the impact sound.

[0086] S53. Conduct NVH verification and effect evaluation; specifically, this includes comparing the NVH test data, EFI signal data, actual vibration energy level, and actual impact time obtained in step S52 with the NVH test data, EFI signal data, actual vibration energy level, and actual impact time obtained in step S12 to evaluate the effectiveness of the theoretical optimization scheme. If the actual required effect is not achieved, repeat S45 to develop a better solution. Figure 13 This is a graph showing the optimized test data results of this embodiment, with the maximum vibration level starting from... Figure 4 The vibration of the left suspension mounting point was reduced to 21g. Figure 13 The vibration at the left suspension mounting point was 11g (vertical axis), and the maximum vibration at the left suspension mounting point occurred at 7.54 seconds (horizontal axis), meeting the objective NVH requirements. The tester's subjective evaluation improved from 5.5 points to 7 points.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for analyzing and optimizing impact noise in automotive transmission systems, characterized in that, Includes the following steps: S1. Obtain the vehicle's NVH test data and actual impact time, and obtain the design parameters and actual structural parameters of the transmission system components; S2. Based on the design parameters and actual structural parameters, establish a simulation analysis model of the transmission system, and calibrate the simulation analysis model of the transmission system based on NVH test data. Obtain the simulated impact time based on the calibrated simulation analysis model of the transmission system. S3. Evaluate whether the actual impact time matches the simulated impact time. If yes, proceed to step S4. If no, calibrate and adjust the transmission system simulation analysis model until the actual impact time matches the simulated impact time. S4. Adjust the parameters of the transmission system simulation analysis model, perform impact sensitivity analysis on various parameters, and formulate a theoretical optimization scheme. S5. Based on the theoretical optimization scheme, produce prototypes and conduct NVH verification and effect evaluation.

2. The method for analyzing and optimizing the impact sound of a vehicle transmission system's cluster as described in claim 1, characterized in that, Step S1 includes the following steps: S11. Perform NVH testing and obtain NVH test data; and simultaneously collect electronic fuel injection signal data; S12. Based on NVH test data and electronic fuel injection signal data, compare the vehicle operating condition information to determine the actual impact time of the impact sound. S13. Obtain the design parameters of the transmission system components and perform precise measurements on the dimensions of the transmission system components to obtain the actual structural parameters of the transmission system components. The actual structural parameters include the actual precise measured dimensions of each transmission system component and the fit clearance of each contact pair in the transmission system.

3. The method for analyzing and optimizing impact sound in automotive transmission systems according to claim 2, characterized in that, In step S11, the NVH test includes: placing vibration sensors on the vehicle's transmission housing, transmission mount active / passive ends, differential, and wheel hubs, and conducting a Clunk impact sound test on the vehicle under Tip in / out conditions.

4. The method for analyzing and optimizing the impact sound of a vehicle transmission system cluster according to claim 3, characterized in that, In step S12, the vehicle operating condition information includes: accelerator pedal depth, throttle opening, gear position, vibration, engine speed, A / B shaft speed, engine torque, friction torque, clutch pressure, and vehicle speed information.

5. The method for analyzing and optimizing impact sound in automotive transmission systems according to claim 3, characterized in that, In step S13, the transmission system components include: transmission system flywheel clutch spline, gear shift gear, main reduction gear, differential half-shaft spline, half-shaft sliding joint, and half-shaft fixed joint; the mating clearances of each contact pair in the transmission system include: gear backlash, gear sleeve backlash, gear sleeve and hub spline backlash, hub and shaft spline backlash, differential half-shaft angular clearance, differential and transmission shaft spline backlash, and drive shaft circumferential clearance.

6. The method for analyzing and optimizing the impact sound of a vehicle drivetrain cluster according to claim 2, characterized in that, Step S2 includes the following steps: S21. Establish a simulation analysis model of the transmission system based on the design parameters and actual structural parameters; the design parameters include the DMF primary inertia, the DMF secondary inertia, the K0 clutch friction plate inertia, and the motor rotor support inertia. S22. Using the test results obtained from NVH testing, the transmission system simulation analysis model is reverse-calibrated, and the parameters of the transmission system simulation analysis model are adjusted. S23. Based on the calibrated transmission system simulation analysis model, perform simulation analysis of the impact moment to obtain the simulated impact moment.

7. The method for analyzing and optimizing the impact sound of a vehicle drivetrain cluster according to claim 6, characterized in that, Step S4 includes the following steps: S41. Based on the simulation analysis model of the transmission system, analyze the force situation of each contact pair in the transmission system and obtain the force situation of each contact pair. S42. Based on the simulation analysis model of the transmission system, obtain the impact power of each contact pair and determine the contact pair with the largest sound source generated by the impact sound. S43. Adjust the fit clearance of a single contact pair in the transmission system simulation analysis model, compare the changes in impact power before and after the adjustment, and obtain the interactive effects of the gap changes of each contact pair on its own impact power and the impact power of other positions. S44. In the simulation analysis model of the transmission system, change the damping, inertia and stiffness of the transmission system components, compare the changes in impact power before and after the adjustment, and obtain the influence of the damping, inertia and stiffness of the transmission system components on the impact power. S45. Based on the simulation analysis results of steps S42-S44, formulate a theoretical optimization scheme.

8. The method for analyzing and optimizing the impact sound of a vehicle drivetrain cluster according to claim 7, characterized in that, In step S42, the impact power of each contact pair is obtained by inputting a sudden torque change to the transmission system simulation analysis model to simulate Tip in / out, and calculating the impact power of the contact pair by using the impact force F and displacement S output at the gap of each contact pair. ,in It refers to the derivative of displacement S, and V refers to the relative velocity of the impact between the contact pairs.

9. The method for analyzing and optimizing impact sound in a vehicle drivetrain cluster according to claim 7, characterized in that, Step S5 includes the following steps: S51. Based on the theoretical optimization scheme formulated in step S45, produce a physical prototype; S52. Conduct NVH testing on the vehicle with the optimized sample replaced, and simultaneously collect electronic fuel injection signal data. Based on the NVH test data and electronic fuel injection signal data, compare the vehicle operating condition information to determine the actual vibration energy level and actual impact time of the impact sound. S53. Conduct NVH verification and effectiveness evaluation.

10. The method for analyzing and optimizing the impact sound of a vehicle drivetrain cluster according to claim 9, characterized in that, Step S53 includes: comparing the NVH test data, EFI signal data, actual vibration energy level and actual impact time obtained in step S52 with the NVH test data, EFI signal data, actual vibration energy level and actual impact time obtained in step S12, and evaluating the effectiveness of the theoretical optimization scheme.

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