Railway vehicle complex sound source decoupling separation method and system

Abstract

The application discloses a rail vehicle complex sound source decoupling separation method, comprising the following steps: collecting static noise outside a preset distance of the whole rail vehicle; calculating the sound power of the whole rail vehicle static noise source according to the static noise; testing the noise and vibration of the motor and the gear box; carrying out coherence analysis on the vibration and noise of the gear box and the motor, obtaining the frequency spectrum value of the coherence coefficient of the motor and the gear box, and obtaining the sound pressure level of the gear box and the motor noise respectively; combining the dynamic passing noise test result outside the vehicle, the sound power of the whole rail vehicle static noise source, and the sound pressure level of the gear box and the motor noise, and obtaining the sound pressure level of the wheel-rail noise through a whole vehicle noise Vaone calculation model; respectively calculating the sound power of the whole rail vehicle static noise source, the wheel-rail noise, and the passing noise outside the vehicle when the noise of the motor and the gear box acts alone, and obtaining the contribution degree of various noise sources to the noise outside the vehicle. The application can improve the abnormal vibration noise tracing analysis efficiency after the whole vehicle is assembled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rail vehicle noise processing, and particularly relates to a rail vehicle complex sound source decoupling separation method and system. BACKGROUND

[0002] Nowadays, with the adoption of multi-source and multi-mode hybrid power supply design by rail vehicles, the use of hybrid power technology improves the flexibility of locomotive traction power supply, but at the same time, increases the complexity and diversity of noise sources. Meanwhile, the input of rail vehicle noise sources is complex, and the frequency characteristics of noise sources are different. The traditional separation method by disassembling noise sources needs to consume a large amount of test resources and time, and consumes a large amount of manpower and material resources. The traditional vehicle noise source separation method such as OTPA and TPA cannot accurately identify the main influencing factors and contribution of vehicle noise sources under the condition of vehicle noise reverberation.

[0003] Therefore, how to effectively decouple and separate the complex sound source of the rail vehicle is an urgent problem to be solved. SUMMARY

[0004] Therefore, the present application provides a rail vehicle complex sound source decoupling separation method, which can improve the abnormal vibration noise traceability analysis efficiency after the whole vehicle is assembled.

[0005] The present application provides a rail vehicle complex sound source decoupling separation method, comprising:

[0006] Collecting static noise outside a preset distance of the whole rail vehicle;

[0007] Based on a whole vehicle noise Vaone calculation model, calculating the whole vehicle static noise source sound power according to the static noise;

[0008] Testing the noise of the motor and the gear box and the vibration of the motor and the gear box;

[0009] Performing coherence analysis on the vibration and noise of the gear box and the motor to obtain the frequency spectrum value of the coherence coefficient of the motor and the gear box, and respectively obtaining the sound pressure level of the gear box noise and the motor noise;

[0010] Combining the dynamic passing noise test result outside the vehicle, the whole vehicle static noise source sound power, and the sound pressure level of the gear box noise and the motor noise, obtaining the sound pressure level of the wheel-rail noise through the whole vehicle noise Vaone calculation model;

[0011] Respectively calculating the whole vehicle static noise source sound power, the wheel-rail noise, and the passing noise outside the vehicle when the motor and the gear box noise act alone to obtain the contribution of various noise sources to the noise outside the vehicle.

[0012] Preferably, the preset distance is 7.5 m.

[0013] Preferably, the vibration and noise of the gearbox and motor are analyzed for coherence, the frequency spectrum values of the coherence coefficients of the motor and gearbox are obtained, and the sound pressure levels of the gearbox and motor noise are obtained respectively, including:

[0014] According to the formula The vibration and noise of the gearbox and motor are analyzed for coherence, the frequency spectrum values of the coherence coefficients of the motor and gearbox are obtained, wherein xi is the vibration frequency spectrum signal of the vehicle motor or gearbox noise source, y is the test signal frequency spectrum of the noise response point near the motor and gearbox, G xiy is the cross-spectrum energy between the two signals, G xixi is the auto-spectrum energy of signal xi, and Gyy is the auto-spectrum energy of signal y;

[0015] According to the formula The sound pressure levels of the gearbox and motor noise are obtained respectively, wherein x1(f) is the separated gearbox sound pressure level when i=1, γ1(f) is the equivalent coherence coefficient of the gearbox; x2(f) is the separated motor sound pressure level when i=2, and γ2(f) is the average coherence coefficient of the motor.

[0016] Preferably, the vehicle static noise source sound power, wheel-rail noise, and vehicle exterior passing noise when the motor and gearbox noise act alone are calculated respectively, and the contribution of various noise sources to the vehicle exterior noise is obtained, including:

[0017] The vehicle static noise source sound power, wheel-rail noise, and vehicle exterior passing noise when the motor and gearbox noise act alone are calculated respectively, and the contribution of various noise sources to the vehicle exterior noise is obtained according to the formula , wherein η i is the contribution of the i-th sound source, p i is the noise sound pressure level of the i-th sound source at 7.5m, and pt is the total noise sound pressure level of all sound sources acting simultaneously at 7.5m.

[0018] A rail vehicle complex sound source decoupling separation system, comprising:

[0019] A collection module for collecting static noise outside a predetermined distance of the entire rail vehicle;

[0020] A first calculation module for calculating the sound power of the static noise source of the entire vehicle based on the vehicle noise Vaone calculation model according to the static noise;

[0021] A test module for testing the noise of the motor and gearbox and the vibration of the motor and gearbox;

[0022] An analysis module for analyzing the vibration and noise of the gearbox and motor for coherence, obtaining the frequency spectrum values of the coherence coefficients of the motor and gearbox, and obtaining the sound pressure levels of the gearbox and motor noise respectively.

[0023] a second calculation module, configured to obtain the sound pressure level of the wheel-rail noise by the vehicle noise Vaone calculation model in combination with the noise test result of the vehicle exterior dynamic passing, the sound power of the vehicle static noise source, and the sound pressure level of the gearbox and motor noise;

[0024] a third calculation module, configured to respectively calculate the vehicle exterior passing noise when the sound power of the vehicle static noise source, the wheel-rail noise, the motor noise and the gearbox noise act alone, and obtain the contribution degree of various noise sources to the vehicle exterior noise.

[0025] Preferably, the preset distance is 7.5 m.

[0026] Preferably, the analysis module is specifically configured to:

[0027] According to the formula The coherence degree analysis is performed on the vibration and noise of the gearbox and motor to obtain the frequency spectrum value of the coherence coefficient of the motor and gearbox, wherein xi is the vibration frequency spectrum signal of the vehicle motor or gearbox noise source, y is the test signal frequency spectrum of the noise response point near the motor and gearbox, G xiy is the cross-spectrum energy between the two signals, G xixi is the self-spectrum energy of the signal xi, and Gyy is the self-spectrum energy of the signal y.

[0028] According to the formula the sound pressure levels of the gearbox and motor noise are obtained respectively, wherein x1(f) is the gearbox sound pressure level obtained when i=1, γ1(f) is the equivalent coherence coefficient of the gearbox; x2(f) is the motor sound pressure level obtained when i=2, and γ2(f) is the average coherence coefficient of the motor.

[0029] Preferably, the third calculation module is specifically configured to:

[0030] The vehicle exterior passing noise when the sound power of the vehicle static noise source, the wheel-rail noise, the motor noise and the gearbox noise act alone is calculated respectively, and the contribution degree of various noise sources to the vehicle exterior noise is obtained according to the formula , wherein η i is the contribution degree of the i-th sound source, p i is the noise sound pressure level of the i-th sound source at 7.5 m outside, and p t is the total noise sound pressure level of all sound sources acting at 7.5 m outside.

[0031] In summary, the application discloses a rail vehicle complex sound source decoupling separation method, when the rail vehicle complex sound source needs to be decoupled and separated, first, the static noise outside the preset distance of the rail vehicle is collected; then, the static noise source sound power of the whole vehicle is calculated based on the whole vehicle noise Vaone calculation model according to the static noise; the noise of the motor and the gear box and the vibration of the motor and the gear box are tested; the vibration and the noise of the gear box and the motor are analyzed to obtain the frequency spectrum value of the coherence coefficient of the motor and the gear box, and the sound pressure level of the gear box and the motor noise is obtained respectively; the sound pressure level of the wheel-rail noise is obtained through the whole vehicle noise Vaone calculation model by combining the dynamic passing noise test result outside the vehicle, the whole vehicle static noise source sound power and the sound pressure level of the gear box and the motor noise; the contribution of various noise sources to the noise outside the vehicle is obtained by calculating the whole vehicle static noise source sound power, the wheel-rail noise and the noise of the motor and the gear box when acting alone. The application develops a modular vibration noise monitoring method of the main noise sources of the whole vehicle traction power supply (including diesel engine, storage battery, hydrogen fuel, etc.), traction transmission system (including transformer, converter, motor, gear box, wheel-rail, etc.), traction fan, auxiliary fan, etc., establishes the vibration noise coherence function of the main motor and gear box noise sources of the whole vehicle, obtains the sound pressure level of the motor and the gear box through the conversion of the coherence function, obtains the static noise power and the dynamic wheel-rail noise sound pressure based on the reverse calculation of the test data, and finally obtains the contribution of each noise source through the superposition of the sound sources, which can effectively improve the abnormal vibration noise traceability analysis efficiency after the whole vehicle is assembled. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0033] Figure 1 A flow chart of a rail vehicle complex sound source decoupling separation method disclosed by the present application;

[0034] Figure 2 A schematic diagram of a rail vehicle complex sound source decoupling separation system disclosed by the present application;

[0035] Figure 3 A schematic diagram of the coherence coefficient of the gear box and the motor disclosed by the present application;

[0036] Figure 4 A schematic diagram of the noise separation result of the motor and the gear box disclosed by the present application. DETAILED DESCRIPTION

[0037] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0038] As shown in the formula (1), a rail vehicle complex sound source decoupling separation method disclosed in the present application can include the following steps: Figure 1

[0039] S101, collecting static noise outside the rail vehicle by a preset distance;

[0040] When it is necessary to decouple and separate the complex sound source of the rail vehicle, the static noise outside the rail vehicle by a preset distance is collected first, for example, the static noise outside the rail vehicle by 7.5 m is collected.

[0041] S102, calculating the static noise source sound power of the whole vehicle based on the Vaone calculation model of the whole vehicle noise;

[0042] Then, the Vaone calculation model of the whole vehicle noise is established, and the static noise source sound power of the whole vehicle is back calculated according to the static noise test result at the 7.5 m outside the vehicle. The sound source emitting noise when the vehicle is stationary mainly includes diesel engine, storage battery, hydrogen fuel, transformer, converter, traction fan, etc.

[0043] S103, testing the noise of the motor and the gear box and the vibration of the motor and the gear box;

[0044] Then, the noise of the motor and the gear box in the bogie area and the vibration of the motor and the gear box are tested.

[0045] S104, performing coherence analysis on the vibration and noise of the gear box and the motor to obtain the frequency spectrum value of the coherence coefficient of the motor and the gear box, and respectively obtaining the sound pressure level of the noise of the gear box and the motor;

[0046] The coherence function of the vibration signal of the motor and the gear box and the noise in the area of the motor and the gear box is calculated.

[0047] The coherence function is defined as:

[0048] x i is the vibration frequency spectrum signal of the noise source of the vehicle motor or the gear box, y is the test signal frequency spectrum of the noise response point near the motor and the gear box, G xiy is the cross-spectrum energy between the two signals, G xixi is the cross-spectrum energy between the two signals, G i ​the self-spectrum energy of y, and Gyy is the self-spectrum energy of the signal y.

[0049] According to the spectrum values of the coherence coefficients of the motor and the gearbox, the frequencies corresponding to the spectrum peak values of the coherence coefficients of the two are taken as the main energy components of the noise source, and according to the main noise spectrum of the motor and the gearbox and in combination with the total sound pressure levels of the two, the respective noise spectrum of the two is obtained. The relationship between the noise sound pressure level of the motor and the gearbox and the coherence coefficient is shown in formula (2)

[0050]

[0051] wherein x1(f) is the separated gearbox sound pressure level when i = 1, γ1(f) is the equivalent coherence coefficient of the gearbox; x2(f) is the separated motor sound pressure level when i = 2, γ2(f) is the average coherence coefficient of the motor; and the comparison of the coherence coefficients of the motor and the gearbox is shown in FIG. 2, and the separated sound pressure of the motor and the gearbox is shown in FIG. 3. Figure 3 Figure 4

[0052] S105, in combination with the vehicle exterior dynamic passing noise test results, the vehicle static noise source sound power, and the sound pressure levels of the gearbox and the motor noise, the sound pressure level of the wheel-rail noise is obtained through the vehicle noise Vaone calculation model.

[0053] In combination with the vehicle exterior dynamic passing noise test results, the vehicle static noise source sound power, and the sound pressure levels of the gearbox and the motor noise, the sound pressure level of the wheel-rail noise is obtained through the vehicle noise Vaone calculation model.

[0054] S106, the vehicle exterior passing noise when the vehicle static noise source sound power, the wheel-rail noise, and the motor and the gearbox noise act alone is calculated respectively to obtain the contribution degree of various noise sources to the vehicle exterior noise.

[0055] The total sound power of the static noise, the motor, the gearbox, and the wheel-rail noise acting alone is considered respectively, the sound pressure value of the vehicle exterior noise under the action of the noise source alone is obtained through the Vaone calculation model, and the contribution degree of each noise is obtained through formula (3).

[0056]

[0057] wherein ηi is the contribution degree of the i-th sound source, p i is the noise sound pressure level of the i-th sound source at 7.5 m outside, p i is the total noise sound pressure level of all sound sources acting at 7.5 m outside. t

[0058] ​​​In summary, the application efficiently fuses test data and simulation calculation data, establishes vibration noise coherence functions of main motor and gear box noise sources of the whole vehicle, obtains sound pressure levels of the motor and the gear box through conversion of the coherence functions, reversely obtains static noise power and dynamic wheel rail noise sound pressure based on test data, and finally obtains contribution degrees of each noise source through superposition of sound sources, which can effectively improve abnormal vibration noise tracing analysis efficiency of the whole vehicle after assembly.

[0059] As shown in Figure 2 , a rail vehicle complex sound source decoupling separation system disclosed by the application can include:

[0060] The acquisition module 201 is configured to acquire static noise outside a preset distance of the whole rail vehicle.

[0061] When it is necessary to decouple and separate the complex sound source of the rail vehicle, the static noise outside the preset distance of the whole rail vehicle is first acquired, for example, the static noise outside 7.5 m of the whole rail vehicle is acquired.

[0062] The first calculation module 202 is configured to calculate the static noise source sound power of the whole vehicle based on a whole vehicle noise Vaone calculation model according to the static noise.

[0063] Then, the Vaone calculation model of the whole vehicle noise is established, the static noise source sound power of the whole vehicle is reversely deduced according to the static noise test result at 7.5 m outside the vehicle, and the sound sources that emit noise when the vehicle is stationary mainly include a diesel engine, a storage battery, hydrogen fuel, a transformer, a converter, a traction fan, etc.

[0064] The test module 203 is configured to test the noise of the motor and the gear box and the vibration of the motor and the gear box.

[0065] Then, the noise of the motor and the gear box in the bogie area and the vibration of the motor and the gear box are tested.

[0066] The analysis module 204 is configured to perform coherence analysis on the vibration and noise of the gear box and the motor, obtain the frequency spectrum value of the coherence coefficient of the motor and the gear box, and obtain the sound pressure level of the noise of the gear box and the motor, respectively.

[0067] The coherence function of the vibration signal of the motor and the gear box and the noise in the motor and the gear box area is calculated.

[0068] The coherence function is defined as:

[0069] x i is the vibration frequency spectrum signal of the vehicle motor or gear box noise source, y is the test signal frequency spectrum of the near-field noise response point of the motor and the gear box, G xiy is the cross-spectrum energy between the two signals, and Gxixi For signal x i The self-spectral energy of signal y is Gyy, where Gyy is the self-spectral energy of signal y.

[0070] Based on the spectral values ​​of the coherence coefficients of the motor and gearbox, the frequencies corresponding to the peak values ​​of their coherence coefficients are taken as the main energy components of the noise source. Based on the main noise spectra of the motor and gearbox, combined with their total sound pressure levels, their respective noise spectra are obtained. The relationship between the noise sound pressure levels and coherence coefficients of the motor and gearbox is given in formula (2).

[0071]

[0072] Where x1(f) is the gearbox sound pressure level obtained when i=1, and γ1(f) is the equivalent coherence coefficient of the gearbox; x2(f) is the motor sound pressure level obtained when i=2, and γ2(f) is the average coherence coefficient of the motor; the coherence coefficients of the motor and gearbox are compared as follows: Figure 3 As shown, the sound pressure level of the motor gearbox separation is as follows Figure 4 As shown.

[0073] The second calculation module 205 is used to combine the test results of the dynamic passing noise outside the vehicle, the sound power of the static noise source of the whole vehicle, and the sound pressure level of the gearbox and motor noise, and obtain the sound pressure level of the wheel-rail noise through the Vaone calculation model of the whole vehicle noise.

[0074] Based on the Vaone noise calculation model for the whole vehicle, combined with the results of the dynamic passing noise test outside the vehicle, the sound power of the static noise source of the whole vehicle, and the sound pressure level of the gearbox and motor noise, the sound pressure level of the wheel-rail noise is obtained.

[0075] The third calculation module 206 is used to calculate the sound power of the vehicle's static noise sources, wheel-rail noise, and external noise when the motor and gearbox noise act alone, so as to obtain the contribution of each noise source to the external noise.

[0076] Considering the total static noise power, the sound pressure value of the external noise under the individual action of the motor, gearbox and wheel-rail noise is obtained by Vaone calculation model, and the contribution of each noise is obtained by formula (3).

[0077]

[0078] Where η i p represents the contribution of the i-th sound source. i Let p be the noise sound pressure level of the i-th sound source at a distance of 7.5m. t The total sound pressure level is the noise level when all sound sources act simultaneously at a distance of 7.5m.

[0079] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0080] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0081] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0082] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for decoupling and separating complex sound sources of a rail vehicle, characterized in that, The method comprises the following steps: collecting static noise outside a preset distance of a whole rail vehicle; calculating static noise source sound power of the whole rail vehicle based on a whole vehicle noise Vaone calculation model according to the static noise; testing noise and vibration of a motor and a gear box; performing coherence degree analysis on the vibration and noise of the gear box and the motor to obtain a frequency spectrum value of a coherence coefficient of the motor and the gear box, and obtaining sound pressure levels of the noise of the gear box and the motor respectively; obtaining a sound pressure level of wheel-rail noise through the whole vehicle noise Vaone calculation model in combination with a dynamic passing noise test result outside the vehicle, the static noise source sound power of the whole vehicle, and the sound pressure levels of the noise of the gear box and the motor; calculating the static noise source sound power of the whole vehicle, the wheel-rail noise, and the passing noise outside the vehicle when the noise of the motor and the gear box acts alone respectively to obtain contribution degrees of various noise sources to the noise outside the vehicle; the coherence degree analysis on the vibration and noise of the gear box and the motor to obtain the frequency spectrum value of the coherence coefficient of the motor and the gear box, and the sound pressure levels of the noise of the gear box and the motor respectively comprises: According to the formula The coherence analysis is made on the vibration and noise of the gear box and motor, and the frequency spectrum values of the coherence coefficients of the motor and gear box are obtained, wherein, is the vibration frequency spectrum signal of the vehicle motor or gear box noise source, wherein i=1, is the motor vibration frequency spectrum signal; i=2, is the gear box vibration frequency spectrum signal; is the frequency spectrum of the test signal of the motor and gear box near-field noise response point, is the cross-spectrum energy between two signals, is the cross-spectrum energy between two signals is the self-spectrum energy of the signal is the self-spectrum energy of the signal is the self-spectrum energy of the signal Substituting the formula into the formula respectively, the sound pressure levels of the gearbox and the motor are obtained, where i = 1, is the separated sound pressure level of the motor; i = 2, is the separated sound pressure level of the gearbox; is the average coherence factor of the motor; is the equivalent coherence factor of the gearbox; the calculation of the static noise source sound power of the whole vehicle, the wheel-rail noise, and the passing noise outside the vehicle when the noise of the motor and the gear box acts alone respectively to obtain the contribution degrees of various noise sources to the noise outside the vehicle comprises: The sound power of the whole vehicle static noise source, the wheel-rail noise, the motor and the gear box noise are calculated respectively, and the vehicle outside passing noise is calculated when the motor and the gear box noise act alone. The contribution of various noise sources to the vehicle outside noise is obtained, wherein, the contribution of the i-th sound source is the noise sound pressure level of the i-th sound source at 7.5 m outside is the total noise sound pressure level of all sound sources acting simultaneously at 7.5 m outside is 2. The method of claim 1, wherein, the preset distance is 7.5 m.

3. A rail vehicle complex sound source decoupling separation system, characterized in that, The method comprises the following steps: a collecting module configured to collect static noise outside a preset distance of a whole rail vehicle; a first calculating module configured to calculate static noise source sound power of the whole rail vehicle based on a whole vehicle noise Vaone calculation model according to the static noise; a testing module configured to test noise and vibration of a motor and a gear box; an analysis module configured to perform coherence degree analysis on the vibration and noise of the gear box and the motor to obtain a frequency spectrum value of a coherence coefficient of the motor and the gear box, and obtain sound pressure levels of the noise of the gear box and the motor respectively; a second calculating module configured to obtain a sound pressure level of wheel-rail noise through the whole vehicle noise Vaone calculation model in combination with a dynamic passing noise test result outside the vehicle, the static noise source sound power of the whole vehicle, and the sound pressure levels of the noise of the gear box and the motor; a third calculating module configured to calculate the static noise source sound power of the whole vehicle, the wheel-rail noise, and the passing noise outside the vehicle when the noise of the motor and the gear box acts alone respectively to obtain contribution degrees of various noise sources to the noise outside the vehicle; the analysis module is specifically configured to: According to the formula The coherence analysis is made on the vibration and noise of the gear box and motor, to obtain the frequency spectrum value of the coherence coefficient of the motor and gear box, wherein, is the vibration frequency spectrum signal of the vehicle motor or gear box noise source, wherein i=1, is the motor vibration frequency spectrum signal; i=2, is the gear box vibration frequency spectrum signal; is the frequency spectrum of the test signal of the motor and gear box near-field noise response point, is the cross spectrum energy between two signals, is the self spectrum energy of the signal ; is the self spectrum energy of the signal ; Substituting the formula into the formula respectively, the sound pressure levels of the gearbox and the motor are obtained, wherein, when i = 1, is the separated sound pressure level of the motor; when i = 2, is the separated sound pressure level of the gearbox; is the average coherence coefficient of the motor; is the equivalent coherence coefficient of the gearbox; the third calculating module is specifically configured to: The sound power of the whole vehicle static noise source, the wheel-rail noise, the motor and the gear box noise are calculated respectively, and the vehicle outside passing noise is calculated when the motor and the gear box noise act alone. The contribution of various noise sources to the vehicle outside noise is obtained, wherein, the contribution of the i-th sound source is the noise sound pressure level of the i-th sound source at 7.5 m outside is the total noise sound pressure level of all sound sources acting at 7.5 m outside is 4. The system of claim 3, wherein, the preset distance is 7.5 m.

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