A method for analyzing NVH performance of a whole vehicle power assembly based on component parameters

Abstract

This invention discloses a method for NVH performance analysis of a vehicle powertrain based on component parameters, comprising the following steps: S1, obtaining the boundary loads of the powertrain; S2, obtaining the parameters of each relevant component along the vibration transmission path of the powertrain; S3, calculating the acceleration 'a' at a target point inside the vehicle based on a formula. t , with a t NVH performance data is used to characterize the powertrain. It can identify potential NVH problems early in the project development process and optimize them at the vehicle level; it can also design the parameters of each component according to the vehicle's NVH performance requirements, shortening the project development cycle and reducing costs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile NVH technology, and particularly relates to a method for analyzing the NVH performance of a vehicle power assembly based on component parameters. BACKGROUND

[0002] With the rapid development of the Chinese automobile market, people's requirements for automobile ride comfort are becoming higher and higher, and NVH performance is one of the important indicators for evaluating automobile comfort, wherein NVH is the abbreviation of Noise, Vibration and Harshness. The automobile power assembly is an important source of in-vehicle vibration and noise. For ordinary passenger cars, many vehicle noise problems are caused by the automobile power assembly, and therefore the sound quality of the power assembly will directly affect the NVH performance of the automobile.

[0003] The power assembly is connected to the vehicle body through a suspension system. Before the vehicle is mounted, the power assembly is subjected to a bench NVH test, and the NVH performance of the power assembly is evaluated according to the bench test data. In addition, for the design of the suspension system, which includes a driving end support, a driven end support and a suspension cushion, the NVH performance parameters are usually based on a six-degree-of-freedom simulation model and proposed by the automobile production host factory to the supplier. Then, in the test vehicle stage, the whole vehicle NVH performance is verified by assembling parts. Since there is a lack of whole vehicle mounting verification in the part design stage, this leads to a high risk of whole vehicle NVH performance in the later sample vehicle stage, and it is difficult to optimize the power assembly after the problem occurs, which will result in high cost, difficulty and long cycle. In addition, the suspension system sample often needs to be matched and verified for several rounds, which leads to a long project development cycle and high part cost. If the in-vehicle NVH performance can be predicted before the sample vehicle is mounted, and the power assembly, the suspension system and the vehicle body are optimized according to the in-vehicle NVH risk points, the matching cycle of the related parts in the later stage will be shortened, the number of parts provided by the supplier will be reduced, the transportation cost will be reduced, and the overall project development cost will be reduced.

[0004] CN113515808A discloses a noise prediction method for a power assembly, and CN113609590A discloses a method, device and equipment for predicting in-vehicle noise and a computer storage medium. In the method for predicting the NVH performance of the whole vehicle, the vibration and noise test data of the target power assembly in multiple working conditions are collected, the transfer function from the driving end of the suspension to the driven end of the suspension and the noise transfer function from the driven side of the suspension to the in-vehicle noise are calculated by using the OTPA method, and then the total noise value of the target power assembly is calculated by combining the test data of the bench NVH test of the power assembly.

[0005] The prior art has the following problems: 1. Since the acquisition of the transfer function needs to be based on the test data of the related vehicle model, the prior art can only predict the vehicle noise when the existing vehicle model needs to be equipped with different engines, and cannot predict the noise of a newly developed vehicle model. 2. The OTPA method is used to calculate the transfer function, which needs to be calculated based on the measured operating condition data. Since the matrix inversion process is ill-conditioned, the calculation error is large and the precision is not high. 3. Since the mathematical model between the performance parameters of the suspension and other components and the vehicle noise is not established, the parameters of the related components cannot be designed according to the vehicle interior noise requirements. SUMMARY

[0006] The purpose of the present application is to provide a vehicle powertrain NVH performance analysis method based on component parameters, which can find potential NVH problems at an early stage of project development and optimize at the vehicle level; also can design the parameters of each component according to the vehicle NVH performance requirements, shorten the project development cycle and reduce the cost.

[0007] The vehicle powertrain NVH performance analysis method based on component parameters provided by the present application comprises the following steps:

[0008] S1, acquiring the boundary load of the powertrain ;

[0009] S2, acquiring the parameters of each related component on the vibration transmission path of the powertrain, the parameters comprising:

[0010] the frequency response function of the powertrain active side, the frequency response function matrix of the origin of the first mounting point of the powertrain connected with the suspension active side support under the free boundary condition ;

[0011] the frequency response function of the suspension active side support, the origin frequency response function of the second mounting point of the suspension active side support connected with the powertrain under the free boundary condition , the origin frequency response function of the third mounting point of the suspension active side support connected with the suspension cushion and the frequency response function from the second mounting point to the third mounting point ;

[0012] the dynamic stiffness matrix of the suspension cushion under different set operating conditions and different set suspension loads ;

[0013] the frequency response function of the powertrain passive side, the frequency response function matrix of the origin of the fourth mounting point of the vehicle body connected with the suspension cushion under the actual constraint state and the frequency response function from the fourth mounting point to the target point in the vehicle interior ;

[0014] S3, acceleration of the target point inside the vehicle The formula for calculation is: ,by As NVH performance characterization data of the powertrain, The internal force at the fourth installation point, and The formula for calculation is:

[0015] ;

[0016] In the formula, ω is the angular frequency.

[0017] Further, S1 specifically includes the following steps: S11, at least two triaxial acceleration sensors are arranged near the first mounting point where the powertrain connects to the active side bracket of the suspension or the third mounting point where the active side bracket of the suspension connects to the suspension pad. The arrangement position of the triaxial acceleration sensors is used as the boundary load identification reference point to acquire the data of the triaxial acceleration sensors of the powertrain under different test conditions, and a test condition data matrix is ​​established. ;

[0018] S12, Test the frequency response function from the first installation point to the boundary load identification reference point, and establish the frequency response function matrix. ;

[0019] S13, calculate the boundary load of the powertrain. The calculation formula is ;

[0020] Furthermore, the acquisition of the powertrain active-side frequency response function in S2 specifically involves: under free boundary conditions, a triaxial accelerometer is placed at the first mounting point connecting the powertrain to the active-side suspension bracket. A force hammer is used to excite several first mounting points in the X, Y, and Z directions respectively. The excitation forces in the X, Y, and Z directions are acquired by force sensors mounted on the force hammer, and the corresponding test data from the triaxial accelerometers are obtained. The origin frequency response function of the first mounting point is obtained based on the proportional relationship between the test data output by the triaxial accelerometers and the excitation force. The frequency response function of each first mounting point is tested sequentially, and a matrix of origin frequency response functions for several first mounting points is established. .

[0021] Furthermore, the acquisition of the origin dynamic stiffness and frequency response function of the active suspension bracket in S2 is specifically as follows: Under free boundary conditions, a triaxial acceleration sensor is arranged at the second mounting point connecting the active suspension bracket to the powertrain and at the third mounting point connecting the active suspension bracket to the suspension pad. The origin frequency response function of the second mounting point is obtained by testing with a hammer impact method. The origin frequency response function of the third installation point and the frequency response function from the second mounting point to the third mounting point .

[0022] Furthermore, the acquisition of the passive-side frequency response function of the powertrain in S2 is specifically as follows: With the vehicle body under actual constraints, a triaxial acceleration sensor is placed at the fourth mounting point connecting the vehicle body and the suspension pad; a triaxial acceleration sensor is placed at the vibration target point inside the vehicle; and a microphone is placed at the sound target point. The origin frequency response function matrix of the fourth mounting point is obtained by using a hammer impact method. and the frequency response function from the fourth installation point to the target point inside the vehicle. ;

[0023] Furthermore, the parameters of each relevant component in S2 are obtained through CAE calculation or through physical unit testing.

[0024] Compared with the prior art, the present invention has the following beneficial effects.

[0025] 1. This invention establishes a mathematical model between the parameters of relevant components on the powertrain vibration and noise transmission path and the NVH performance of the whole vehicle. Using this mathematical model, the NVH performance of the whole vehicle powertrain is predicted, the NVH performance risk points in the vehicle are quickly identified, and the parameters of each component on the vibration and noise transmission path are designed according to the NVH performance requirements of the whole vehicle.

[0026] 2. The analysis method described in this invention can quickly evaluate a large number of design change components, advance the whole vehicle NVH design and component verification work, discover potential NVH problems in the early stage of project design and development, and perform whole vehicle-level optimization, avoiding the increased costs caused by changing the solution after discovering problems in the later stage of the project.

[0027] 3. This invention only requires each component supplier to provide the relevant parameters of the component to the vehicle OEM, without having to transport each component to the OEM to assemble a complete test vehicle, so that the NVH performance of the whole vehicle powertrain can be verified. This greatly shortens the project development cycle and reduces the round-trip transportation costs of parts.

[0028] 4. The excitation force of the powertrain can be tested on a test bench or on a complete vehicle without removing the powertrain. It is easy to implement in engineering and the excitation force obtained is not affected by the passive side mounting structure. It can independently characterize the characteristics of the excitation source. Thus, for a complete vehicle project equipped with the same powertrain, only the powertrain characteristics need to be tested once to predict the in-vehicle noise and vibration. Attached Figure Description

[0029] Figure 1This is a schematic diagram showing the connection between the powertrain and the vehicle body;

[0030] Figure 2 This is a schematic diagram of the force analysis of the powertrain;

[0031] Figure 3 This is a schematic diagram of the force analysis of the active suspension bracket;

[0032] Figure 4 This is a schematic diagram of the force analysis of the suspended cushion;

[0033] Figure 5 This is a schematic diagram of the force analysis of the vehicle body;

[0034] Figure 6 This is a schematic diagram illustrating the effect of boundary loads;

[0035] Figure 7 This is a flowchart illustrating the NVH performance analysis method for the whole vehicle powertrain based on component parameters as described in this invention.

[0036] In the diagram, 1—virtual load application location inside the powertrain, 2—first mounting point, 3—third mounting point, 4—fourth mounting point, 5—target point inside the vehicle; A—powertrain, B—body, M—active side suspension bracket, K—suspension pad. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] See Figure 7 The NVH performance analysis method for the whole vehicle powertrain based on component parameters, shown below, includes the following steps:

[0039] S1, Obtain the boundary load of the powertrain. A reference point is set near the powertrain installation location, and the operating condition test data of the reference point and the frequency response function from the installation point to the reference point are obtained. The boundary load is solved using the inverse matrix method, which includes the following steps.

[0040] S11, two triaxial acceleration sensors are arranged near the first mounting point connecting the powertrain and the active side bracket of the suspension. The arrangement position of the triaxial acceleration sensors is used as the boundary load identification reference point to acquire the data of the triaxial acceleration sensors of the powertrain under different test conditions, and a test condition data matrix is ​​established. The test conditions include acceleration, deceleration, constant speed, and idling.

[0041] To ensure the accuracy of load identification, the distances from the two triaxial accelerometers to the first mounting point are set differently. If there are multiple first mounting points as excitation sources, at least two triaxial accelerometers need to be placed near each first mounting point to form a test condition data matrix for all reference points.

[0042] S12, the frequency response function from the first installation point to the boundary load identification reference point is tested using the hammer impact method, and the frequency response function matrix is ​​established. .

[0043] When using the hammer impact method for testing, the triaxial sensors at the reference point are positioned identically to those used in the operational test. The hammer excites each first mounting point in the X, Y, and Z directions. Force sensors mounted on the hammer acquire the excitation force in each direction, and the corresponding triaxial accelerometer data is obtained. The frequency response function from the first mounting point to the boundary load identification reference point is obtained based on the ratio of the triaxial accelerometer output data to the excitation force. Following this method, excitation is applied to each first mounting point in the X, Y, and Z directions, resulting in the frequency response function matrix from the first mounting point to the boundary load identification reference point. .

[0044] S13, calculate the boundary load of the powertrain. The calculation formula is .

[0045] S2, acquire the parameters of each relevant component along the powertrain vibration transmission path. These parameters are obtained through CAE calculations or through physical unit tests. In this embodiment, the parameters are obtained through physical unit tests. Specifically, the parameters include: the powertrain's active-side frequency response function, the origin dynamic stiffness and frequency response function of the active-side suspension bracket, the dynamic stiffness matrix of the suspension pad, and the powertrain's passive-side frequency response function.

[0046] The frequency response function of the powertrain's active side is determined by the following method: Under free boundary conditions, a triaxial accelerometer is placed at the first mounting point connecting the powertrain to the active side suspension bracket. A force hammer is used to excite several first mounting points in the X, Y, and Z directions. The excitation forces in the X, Y, and Z directions are acquired by force sensors mounted on the force hammer, and the corresponding test data from the triaxial accelerometers are obtained. The origin frequency response function of the first mounting point is obtained based on the proportional relationship between the test data output by the triaxial accelerometers and the excitation force. The frequency response function of each first mounting point is tested sequentially, and a matrix of origin frequency response functions for several first mounting points is established. .

[0047] The frequency response function of the active suspension bracket was determined by placing a triaxial accelerometer at each of the two mounting points: the second mounting point connecting the active suspension bracket to the powertrain and the third mounting point connecting the active suspension bracket to the suspension pad, under free boundary conditions. The origin frequency response function at the second mounting point was obtained using a hammer impact method. The origin frequency response function of the third installation point and the frequency response function from the second mounting point to the third mounting point .

[0048] Dynamic stiffness matrix of suspension pad under different operating conditions and different suspension loads ;

[0049] The frequency response function of the passive side of the powertrain was obtained under actual vehicle constraints. A three-dimensional acceleration sensor was placed at the fourth mounting point where the vehicle body connects to the suspension pad. A three-dimensional acceleration sensor was also placed at the vibration target point inside the vehicle, and a microphone was placed at the sound target point. The frequency response function matrix at the origin of the fourth mounting point was obtained using a hammer impact method. and the frequency response function from the fourth installation point to the target point inside the vehicle. .

[0050] The parameter data of the components mentioned above can be provided by their respective suppliers after testing, without having to be shipped to the OEM, which greatly advances project development and saves project development costs.

[0051] S3. Establish a virtual assembly model of the vehicle powertrain NVH based on component parameters, and substitute the parameters obtained in S1 and S2 into the virtual assembly model to calculate the vehicle NVH response, that is, calculate the acceleration of the target point inside the vehicle.

[0052] acceleration of the target point inside the vehicle The formula for calculation is: ,by As NVH performance characterization data of the powertrain, The internal force at the fourth installation point, and The formula for calculation is:

[0053] ;

[0054] In the formula, ω is the angular frequency.

[0055] Vehicle NVH (Noise, Vibration, and Harshness) analysis typically includes three parts: excitation source, transmission path, and response. (See also...) Figure 1The powertrain and vehicle body connection structure shown includes a powertrain A, an active side suspension bracket M, a suspension pad K, and a vehicle body B connected in sequence, with excitation source F. s Virtual load application location 1 for the internal load of the powertrain. Perform force analysis on each component individually.

[0056] See Figure 2 Force analysis of powertrain A yields the following force and acceleration equations:

[0057] ;

[0058] In the formula, The acceleration of the first installation point, The frequency response function from the virtual application position of the internal load of the powertrain to the first mounting point. For the internal load of the powertrain, Let the powertrain be defined as the origin frequency response function of the first mounting point under free boundary conditions or preload conditions. The internal force at the first installation point.

[0059] See Figure 3 Force analysis of the active suspension bracket M yields the following results:

[0060] ;

[0061] .

[0062] See Figure 4 Force analysis of the suspended cushion K yields the following results:

[0063] ;

[0064] In the formula, For the internal force at the third installation point 3, For the internal force at the fourth installation point 4, For the dynamic stiffness of the suspended cushion, The acceleration of the third installation point 3 under test conditions. The acceleration of the fourth installation point under test conditions. ω is the angular frequency.

[0065] See Figure 5 Force analysis of vehicle body B yields the following results:

[0066] ;

[0067] In the formula, Let be the origin frequency response function of the fourth mounting point of vehicle body B under free boundary conditions or preload conditions.

[0068] The acceleration of target point 5 inside the vehicle is:

[0069] ;

[0070] In the formula, The acceleration of the target point inside the vehicle. This is the frequency response function from the fourth installation point to the target point inside the vehicle.

[0071] Based on the above calculation formula, we can derive:

[0072] .

[0073] exist In the calculation formula, due to the load inside the excitation source It is generally impossible to obtain and has no practical application location, therefore it will Transformed into a boundary load acting at its first mounting point 2 The boundary load It has a definite and identifiable point of application. To ensure the equivalence of the transformation, this boundary load... With the internal load of the excitation source The accelerations generated at target point 5 inside the vehicle must be equal. See [link to boundary load description] for details. Figure 6 ,against Figure 6 Each component was subjected to stress analysis individually.

[0074] Force analysis of the powertrain yields the following force and acceleration equations:

[0075] .

[0076] Force analysis of the active side suspension bracket M, suspension pad K, and vehicle body B Figures 3 to 5 The same applies, therefore the boundary load is obtained. The expression for the resulting interface internal forces is:

[0077] ;

[0078] Boundary loads The resulting acceleration of the target point inside the vehicle is:

[0079] .

[0080] Due to internal load With boundary load If the acceleration response generated at the target point inside the vehicle is equal, then:

[0081] .

[0082] It can be seen that the boundary load It is only related to the characteristics of powertrain A itself, and has nothing to do with the suspension system and the vehicle body, and is independent of the installation state of the powertrain. Therefore, this boundary load can characterize the independent characteristics of the powertrain, and can be obtained on a test bench or on the vehicle.

[0083] In the virtual assembly model of the whole vehicle of this invention, the variables are all independent parameter characteristics of each component. Therefore, only the data of each component needs to be obtained, and whole vehicle assembly is not required to perform whole vehicle-level system verification. This greatly advances the whole vehicle NVH performance design and component verification work, making it easier to discover and control problems at an early stage and saving project development costs.

[0084] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for analyzing the NVH performance of a vehicle powertrain based on component parameters, characterized in that, Includes the following steps: S1, Obtain the boundary load of the powertrain. ; S2, Obtain the parameters of each relevant component along the powertrain vibration transmission path, the parameters including: The frequency response function of the powertrain's active side, and the origin frequency response function matrix of the powertrain at the first mounting point where it connects to the active side suspension bracket under free boundary conditions. ; The frequency response function of the active suspension bracket; the origin frequency response function of the second mounting point where the active suspension bracket connects to the powertrain under free boundary conditions. The origin frequency response function of the third mounting point where the active suspension bracket connects to the suspension pad. and the frequency response function from the second mounting point to the third mounting point ; Dynamic stiffness matrix of suspension pad under different operating conditions and different suspension loads ; The frequency response function of the powertrain passive side, the origin frequency response function matrix of the fourth mounting point where the vehicle body connects to the suspension mount under actual constraints. and the frequency response function from the fourth installation point to the target point inside the vehicle. ; S3, acceleration of the target point inside the vehicle The formula for calculation is: ,by As NVH performance characterization data of the powertrain, The internal force at the fourth installation point, and The formula for calculation is: ； In the formula, ω is the angular frequency.

2. The NVH performance analysis method for a vehicle powertrain based on component parameters according to claim 1, characterized in that, S1 specifically includes the following steps: S11, at least two triaxial acceleration sensors are arranged near the first mounting point where the powertrain connects to the active side bracket of the suspension or the third mounting point where the active side bracket of the suspension connects to the suspension pad. The arrangement position of the triaxial acceleration sensors is used as the boundary load identification reference point. Data from the triaxial acceleration sensors of the powertrain under different test conditions are obtained, and a test condition data matrix is ​​established. ; S12, Test the frequency response function from the first installation point to the boundary load identification reference point, and establish the frequency response function matrix. ; S13, calculate the boundary load of the powertrain. The calculation formula is .

3. The NVH performance analysis method for a vehicle powertrain based on component parameters according to claim 1 or 2, characterized in that, The acquisition of the powertrain active-side frequency response function in S2 is specifically as follows: Under free boundary conditions, a triaxial accelerometer is placed at the first mounting point connecting the powertrain to the active-side suspension bracket. A force hammer is used to excite several first mounting points in the X, Y, and Z directions respectively. The excitation force in the X, Y, and Z directions is acquired by the force sensor mounted on the force hammer, and the corresponding test data of the triaxial accelerometer is acquired. The origin frequency response function of the first mounting point is obtained based on the proportional relationship between the test data output by the triaxial accelerometer and the excitation force. The frequency response function of each first mounting point is tested sequentially, and a matrix of origin frequency response functions for several first mounting points is established. .

4. The NVH performance analysis method for a vehicle powertrain based on component parameters according to claim 1 or 2, characterized in that, The frequency response function of the active suspension bracket in S2 is obtained as follows: Under free boundary conditions, a triaxial acceleration sensor is placed at the second mounting point where the active suspension bracket connects to the powertrain and at the third mounting point where the active suspension bracket connects to the suspension pad. The origin frequency response function of the second mounting point is obtained by testing with a hammer impact method. The origin frequency response function of the third installation point and the frequency response function from the second mounting point to the third mounting point 5. The NVH performance analysis method for a vehicle powertrain based on component parameters according to claim 1 or 2, characterized in that, The acquisition of the passive-side frequency response function of the powertrain in S2 is specifically as follows: With the vehicle body under actual constraints, a triaxial acceleration sensor is placed at the fourth mounting point connecting the vehicle body and the suspension pad. A triaxial acceleration sensor is also placed at the vibration target point inside the vehicle, and a microphone is placed at the sound target point. The origin frequency response function matrix of the fourth mounting point is obtained using a hammer impact method. and the frequency response function from the fourth installation point to the target point inside the vehicle. .

6. The NVH performance analysis method for a vehicle powertrain based on component parameters according to claim 1 or 2, characterized in that: The parameters of each relevant component in S2 are obtained through CAE calculation or through physical unit testing.

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