CN101464168B - Noise source recognition method for vehicle acceleration noise - Google Patents

Abstract

The invention relates to a method for indentifying a noise source that produces noise when a vehicle accelerates, and belongs to the technical field of vehicle noise control. The method comprises the following steps: when the vehicle accelerates or travels at a uniform speed, the noise source signal, the vibration source signal, the speed signal, the response point sound pressure signal, the vehicle position signal and the like are collected; the transfer function matrix from the noise source and the vibration source to the response point is calculated; the changing response point sound pressure during the process of acceleration is synthesized and computed; and the sensitivity and the contribution degree of each noise source and vibration source are calculated. The invention has the following advantages: the noise source signal, the vibration source signal, the vehicle travelling state signal, and the ground response point sound pressure signal, which are collected during the running of the vehicle, can be utilized for accurately identifying the noise source that produces noise during the acceleration; and the quantitative relationship between the response point noise signal and each noise source is obtained and can provide a reliable basis for the reduction of noise produced by the acceleration of a running vehicle.

Description

A kind of Noise Sources Identification method of vehicle acceleration noise

Technical field

The present invention relates to a kind of Noise Sources Identification method of vehicle acceleration noise, belong to vehicle noise control technology field.

Background technology

Automobile noise is the main source of noise pollution, the many countries that comprise China have all formulated strict rules and have come Control of Automobile noise (the standard GB 1495-2002 that formulates recently as China), reduce automobile noise has obtained countries in the world and each main car load manufacturing enterprise and parts enterprise as an important topic of current automotive engineering development extensive attention.Accurate identification to sound source is the key that reduces noise emitted by accelerating motor vehicle.

Present noise testing comprises test and acoustical holography test at ISO362, has adopted different apparatus and method respectively.The former is as B﹠amp; (the Vehicle pass-by noise test of the PULSE system of K, www.bksv.com), gather engine speed, throttle opening and CAN bus parameter signal onboard, gather vehicle speed signal, response point sound pressure signal on ground, carry out communication by wireless lan transceiver.Noise source, vibration source information that this is tested on the collection vehicle not mainly are the relations between record noise emitted by accelerating motor vehicle and running velocity, the throttle operation, thereby can not carry out the identification in pass-by noise source.Acoustical holography test (method for analyzing surficial acoustic field of high-speed moving object, patent of invention 00132123.4 China) can test out the surface of vehicle sound field, but can not identify noise source, vibration source on the car of sound field correspondence.

Summary of the invention

The Noise Sources Identification method that the objective of the invention is a kind of vehicle acceleration noise, the noise signal of utilizing noise source, vibration source, transport condition information and ground response point that vehicle measures is under steam discerned the overriding noise source that vehicle gives it the gun in the process, and obtain each noise source, thereby provide effective foundation for reducing noise to response point The noise relation.

The Noise Sources Identification method of the vehicle acceleration noise that the present invention proposes may further comprise the steps:

(1) on tested vehicle, be provided for the sound pressure signal of measuring vehicle noise source, the vibration acceleration signal of vibration source and the sensor of vehicle speed signal v (t),

Two locating devices are placed on the acceleration start line and end of boost line of vehicle ' road respectively, are used to obtain vehicle location signal,

Two microphones are placed and two the corresponding test road of locating device mid point both sides, are used to measure response point noise sound pressure signal,

Thermometer and wind gage are placed above-mentioned microphone next door, be used for measures ambient temperature and real-time wind speed;

(2) tested vehicle is travelled along the center line of test road, the sensor, locating device, microphone while acquired signal before vehicle quickens, when the front portion of vehicle arrives the acceleration start line of test road, full throttle give it the gun by, when vehicle passes through the end of boost line, accelerator finishes, select a speed of a motor vehicle when giving it the gun the different speed of a motor vehicle of vehicle, vehicle is at the uniform velocity travelled on the test road with this speed of a motor vehicle, tracer signal, select a plurality of different speed of a motor vehicle respectively, repeat at the uniform velocity to travel tracer signal;

(3) calculate vehicle in the particular moment of testing the road driving process, the distance between vehicle and the above-mentioned microphone:

$s\left(t\right)=\sqrt{{(\underset{t_0}{\overset{t}{\∫}}v\left(t\right)\·\mathrm{dt}+s_0)}^2+L^2}$

Wherein, v (t) is the speed of a motor vehicle of vehicle at t, t ₀Be the moment of vehicle by the acceleration start line, s ₀For quickening the distance between start line and the above-mentioned microphone, L is that microphone is to the distance of testing road axis;

(4) according between above-mentioned vehicle speed signal v (t) and vehicle and the above-mentioned microphone apart from s (t), the sound pressure signal of microphone is handled, eliminate Doppler effect, process is as follows:

According to t constantly between vehicle and the above-mentioned microphone apart from s (t), calculate the time t that microphone is arrived in noise transmission that this moment vehicle sends _s:

$t_s=\frac{s\left(t\right)}{c}$

Wherein c is the velocity of sound at that time, and the noise of vehicle will be at t+t _sConstantly propagate into response point microphone place, utilize the time domain interpolation method that the sound pressure signal of above-mentioned microphone collection is converted into noise emission response point noise sound pressure signal constantly;

(5) from the moment t of vehicle by the acceleration start line ₀Beginning, vehicle is whenever travelled the vibration acceleration signal of sound pressure signal, vibration source of the noise source that setpoint distance write down and response point sound pressure signal as a signal spacing, obtains this signal spacing internal noise source and vibration source and be to the transfer function matrix H (f) of response point:

$H\left(f\right)=\left[h_i\left(f\right)\right]=\frac{p_i\left(f\right)}{a_i\left(f\right)}$

H wherein _i(f) be on the vehicle i noise source or vibration source to the transport function of response point, a _i(f) be i noise source or the noise sound pressure signal of vibration source or the Fourier transform results of vibration acceleration signal on the vehicle, p _i(f) be the Fourier transform results of the noise sound pressure signal that i noise source or vibration source produce in response point on the vehicle, repeat this process, obtain the transfer function matrix H (f) in whole unlike signals interval;

(6) utilize the transfer function matrix H (f) in above-mentioned whole unlike signals interval, splice the give it the gun response acoustic pressure time-domain signal P (t) of process of vehicle and be:

$P\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}{P}_i\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(P_i\left(f\right)\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\left(f\right)\right)$

Wherein, P _i(t) be the response acoustic pressure time-domain signal of i signal spacing, P _i(f) be the response acoustic pressure frequency-region signal of i signal spacing, A _{I, n}(f) be the noise source sound pressure signal of i signal spacing and the frequency-region signal of vibration source vibration acceleration signal, H _{I, n * m}(f) be the transfer function matrix of i signal spacing calculating according to top method;

(7) utilize the give it the gun transfer function matrix of process of above-mentioned vehicle, calculate on the vehicle each noise source and vibration source to the sensitivity and the contribution degree of response point sound pressure signal:

The response point overall noise is to the sensitivity L of p noise source _Total(L _p-Δ) be:

$L_{\mathrm{total}}(L_P-\mathrm{\Δ})=20{\log }_{10}\frac{\sqrt{\frac{\underset{t_1}{\overset{t_m}{\mathrm{\Σ}}}{\left[\mathrm{ifft}(\mathrm{fft}\left({\left[A\right|S]}^{\′\′}\left(t\right)\right)\·H\left(f\right))\right]}^2}{m}}}{p_0}$

P wherein ₀Be canonical reference pressure, m is a sampling number in the signal spacing, [A|S] " expression p noise source sound pressure level L _nReduce the noise source signal matrix behind the Δ, the sound pressure level reduction of Δ for setting,

Noise source or vibration source to the contribution degree of response point sound pressure signal are:

${\mathrm{\γ}}_p=[1-\frac{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n-1}\left(f\right)H_{i,(n-1)\×(m-1)}\right)}{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\right)}]\×100\%$

A wherein _{I, n-1}(f) be the remaining noise source sound pressure signal behind p noise source of rejecting or the vibration source and the frequency-region signal of vibration source vibration acceleration signal, H _{I, (n-1) * (m-1)}For rejecting the transfer function matrix behind p noise source or the vibration source.

The Noise Sources Identification method of the vehicle acceleration noise that the present invention proposes, its advantage is:

1, utilizes the inventive method, can utilize sound pressure signal of the noise source that measures in the vehicle ' process and vibration source signal and vehicle running state signal, surface noise monitoring location etc., carry out the identification of noise source, and the outer noise source position of quickening by noise of car can identify vehicle and give it the gun the time.

2, utilize the inventive method, the quantitative relationship between spot noise signal and each noise source of can meeting with a response, therefore recognition result of the present invention can be used as and improves the reliable basis that car quickens running noise outward.

Description of drawings

Fig. 1 is the layout synoptic diagram that is used to obtain the various sensors of relevant information in the inventive method.

Fig. 2 is the FB(flow block) of the inventive method.

Among Fig. 1, the 1st, locating device, the 2nd, vehicle quickens start line, the 3rd, tested vehicle, the 4th, microphone, the 5th, vehicle ' road, the 6th, vehicle end of boost line.

Embodiment

When outside the car that carries out the GB regulation, quickening to pass through the identification of noise, the driving information that needs noise, vibration signal and vehicle on the collection vehicle also need be gathered response point sound pressure signal, vehicle location signal, ambient signal of monitoring location etc. in addition on ground.

One embodiment of the present of invention are the gatherer process of each signal on the example explanation vehicle a preposition rear-guard type automobile is carried out outer the acceleration by noise source identification test of car.

On vehicle, utilize harvester to gather the driving information of the noise signal of each noise source and vibration source and vibration signal, vehicle (as engine speed, the speed of a motor vehicle, throttle opening etc., what gather in the example is engine rotational speed signal), utilize wireless transceiver that the signal on the vehicle is transferred to the harvester on ground or receives the signal that the ground harvester sends, realize signal synchronous collection and real-time communication on ground and the vehicle.Utilize microphone to gather the noise sound pressure signal of the noise source on the car two, microphone fixing (is no more than 100mm apart from the sound source distance) near tested noise source according to vehicle structure.Utilize acceleration transducer to come the vibration signal of each vibration source on the measuring vehicle, acceleration transducer is fixed on (being no more than 100mm apart from vibration source) near the vibration source according to vehicle structure equally.

The riding position of sensor is described according to example below.The noise source of vehicle is divided into air sound source and structural vibration source.Measure its noise sound pressure signal for the air sound source with microphone, utilize acceleration transducer to measure its vibration acceleration signal for the structural vibration source.The air sound source of vehicle mainly can be divided into mechanic sound, burning sound, airflow noise and tire sound etc.Mechanic sound is mainly engine timing gear chamber, engine sump tank, variator, main reducing gear and produces; Combustion noise is mainly the radiated noise of engine cylinder-body and cylinder head generation; The air-flow sound source is mainly radiator fan, air cleaner, draft tube, exhaust manifold, tailpipe and the vehicle body outside; Tyre noise comes from 4 wheels, and therefore the noise sound pressure signal that microphone is measured the relevant position is installed near above-mentioned each position.The vehicle structure vibration source is mainly link position and other mounting structures of link position, driving system and the vehicle body of power drive mechanism and vehicle body, therefore main vibration source measurement point be that engine mounting, variator suspend, transmission shaft suspends, main reducing gear suspends, gas outlet suspends, suspension and the link position of vehicle body and the link position of suspension and axle housing etc., measure its vibration acceleration signal at these position of sound production acceleration transducers.For structures such as engine mounting, main reducing gear suspend, when the measuring vibrations acceleration signal, to measure its three-dimensional acceleration signal simultaneously.

Need gather noise sound pressure signal, the position signalling of vehicle, the environmental information (comprising wind speed, temperature etc.) of response point on ground.Lay microphone (recommend riding position at 7.5m place, road axis both sides, microphone is apart from floor level 1.2m) at the test position of experiment road both sides, be used for measuring the noise sound pressure signal of test position; Be used for measures ambient temperature and wind speed in real time at other thermometer and the wind gage laid of road, be used for the sound pressure signal that records is proofreaied and correct; Respectively settle one group of locating device at reference position and final position (recommending to quicken starting point and terminating point) that vehicle gives it the gun at 20m place, both sides, noise testing position, when vehicle ' is passed through the position of locating device, vehicle can block laser, thereby can in locating device, produce step signal, thereby determine that headstock arrives the moment of locating device, utilize two groups of locating devices just can determine vehicle by quickening the moment of reference position and final position, thereby the position of vehicle is calculated; The signal that utilizes wireless transmitter that the ground harvester is collected is transferred to harvester on the car or receives the signal that transmission comes on the vehicle, realize on the car and the synchronous acquisition and the real-time communication on ground, concrete adopt send on the car ground receive mode still be on the ground transmission car receive mode determine according to actual conditions by the operator, what use in the example is that ground sends signal, and received signal is carried out the mode of synchronous acquisition on the vehicle.

In the test process, obtain relevant information various sensors layout as shown in Figure 1, be example explanation test process with the Noise Sources Identification that a preposition rear-guard vehicle is carried out.

(1) test site condition

Specifying measurement condition according to national legislation, no big acoustic reflection thing in the 50m radius around the test site, as fence, rock, bridge or buildings etc., experiment road surface and all the other place dry tack frees, experiment road surface basic horizontal, solid, smooth, the response point wind speed is no more than 5m/s during test, and ground unrest (A weighted sound pressure level) is at least than the low 10dbB of tested vehicle noise, the long 20m of acceleration region.

(2) proving installation is installed

Debugging tested vehicle 3 is in the cruising state, arranging on the vehicle that harvester as previously mentioned on the car, sensing station comprises front said each overriding noise source and vibration source, guarantees sensor signal effectively, accurately, and the operator carries out acquisition operations onboard.

Arrange microphone 4 as shown in the figure in experiment road 5 both sides apart from center line 7.5m place, microphone is apart from floor level 1.2m, each 10m place is decided to be acceleration start line 2 and end of boost line 7 in the microphone both sides, lay locating device 1 respectively, guarantee that laser that locating device sent can be covered by vehicle body when quickening start line 2 and end of boost line 7 at vehicle, produce corresponding step signal with definite moment, thereby calculate the position s (t) of vehicle to microphone by the initial sum final position.Utilize harvester to gather the signal of laser locating apparatus, microphone, wind gage and thermometer, and utilize wireless transmitter to be transferred on the vehicle signal that collects, carry out synchronous acquisition and record onboard by the operator.

(3) test process

At first carry out the vehicle test of giving it the gun, testing a certain gear gets off when quickening noise source outward, tested vehicle 3 travels along the center line of experiment road 5, vehicle is controlled acquisition system by the operator on the car during near test segment and is begun acquired signal, when headstock arrives when quickening start line 2 pedal of stepping on the throttle with all strength, tested vehicle 3 along the road axis full throttle give it the gun by, when vehicle passes through end of boost line 7, unclamp gas pedal, accelerator finishes.So carry out 3 to 4 tests.The test of at the uniform velocity travelling then according to the speed of a motor vehicle variation range of tested vehicle in the accelerator, is selected wherein several speed of a motor vehicle, allows tested vehicle 3 at the uniform velocity travel by tested highway section, tracer signal with these speed of a motor vehicle.Total give it the gun and at the uniform velocity travel times be no less than noise source and the vibration source number sum that will analyze.

As the tested vehicle in the example 3, its 3 grades gives it the gun by noise of test analysis arranges altogether that on vehicle 33 sensors measure its noise source and vibration source signal.At first carry out giving it the gun by experiment of No. 4 vehicles, vehicle speed of a motor vehicle by the acceleration highway section time changes to about 65km/h from 15km/h.Allow tested vehicle 38 at the uniform velocity travel by tested highway section with the speed of a motor vehicle 15,20,25,30,35,40,45,50,55,60,65km/h respectively then, and tracer signal, every kind of test car speed 3 times.At the uniform velocity travel altogether and test 33 times, the test 4 times of giving it the gun amounts to 37 times, greater than the noise source that will analyze and vibration source sum.

Under will measuring a plurality of gears, during the acceleration running noise level source, should carry out experiments of measuring respectively to every kind of gear by above-mentioned requirements.

The detailed process of the Noise Sources Identification of automobile acceleration noise is as shown in Figure 2:

1, calculates car speed and position

Utilize the vehicle speed signal of collection and speed of a motor vehicle situation of change and the traveling-position information in the position signalling calculating vehicle ' process.

Write down the engine rotational speed signal n (t) of vehicle in the example, speed of a motor vehicle v (t) can calculate according to following formula

$v\left(t\right)=\frac{n\left(t\right)}{60\·i_g\·i_d}\·2\mathrm{\πR}$

Wherein, v (t) is the speed of a motor vehicle of vehicle at t, and n (t) is a vehicle at the engine rotational speed signal in this moment, i _gBe this transmission ratio constantly, i _dBe this main reducing gear ratio of gear constantly, R is the driving wheel of vehicle tire radius,

What vehicle was carved into the response point microphone when t apart from s (t) is:

$s\left(t\right)=\sqrt{{(\underset{t_0}{\overset{t}{\∫}}v\left(t\right)\·\mathrm{dt}+s_0)}^2+L^2}$

Wherein, t ₀Be the moment of vehicle by the acceleration start line, s ₀Be t ₀Vehicle promptly quickens the distance of reference position to the response point microphone to the distance of microphone constantly, and L is the distance of response point microphone to road axis;

Utilize the speed of a motor vehicle and vehicle position information, the response point sound pressure signal is handled, eliminate Doppler effect.

, can calculate and carve noise transmission that vehicle sends time t at this moment in t position constantly by vehicle to the response point microphone _sFor:

$t_s=\frac{s\left(t\right)}{c}$

Wherein s (t) is vehicle is carved into the response point microphone when t a distance, and c is the velocity of sound at that time, so the noise of this moment vehicle will be at t+t _sConstantly propagate into response point microphone place, the method for utilizing time domain interpolation thus is scaled noise emission noise sound pressure signal constantly with the sound pressure signal of response point microphone collection.

From initial moment t ₀Beginning is whenever travelled noise source, vibration source signal and response point sound pressure signal that a bit of distance (being generally 0.25m) write down as a signal spacing with vehicle, and noise source and vibration source to the transfer function H (f) of response point are on the car

$H\left(f\right)=\left[h_i\left(f\right)\right]=\frac{p_i\left(f\right)}{a_i\left(f\right)}$

H wherein _i(f) be the transport function of i driving source (noise source or vibration source), a to response point _i(f) be the Fourier transform results of the signal (noise sound pressure signal or vibration acceleration signal) of i driving source, p _i(f) be the Fourier transform results of i driving source at the noise sound pressure signal of response point generation.

The sound pressure signal of ground left and right sides response point is the stack that each vibration source, sound source encourage caused response on the car during vehicle ', and the response point sound pressure signal is

p(f)＝a ₁(f)h ₁(f)+a ₂(f)h ₂(f)+...+a _n(f)h _n(f)

A wherein ₁(f) to a _n(f) be respectively the Fourier transform results of n noise source and vibration source signal, h ₁(f) to h _n(f) be respectively this n noise source and the vibration source transport function to response point, p (f) is the Fourier transform results of response point sound pressure signal.

For one group of " excitation-response " signal (corresponding signal spacing) that n exciting signal source (noise source and vibration source) and m response point are arranged, total m equation and m * n unknown number.If co-exist in k group " excitation-response " signal, then response point sound pressure signal section is expressed as:

P _k×m(f)＝A _k×n(f)H _n×m(f)

H in the formula _{I, j}(f) (i＜n, j＜m) are the transport function of i sound source reference point to j response point, a _{O, i}(f) (o＜k, i＜n) are the Fourier transform results of i sound source reference point signal in measuring for the o time, p _{O, j}(f) (o＜k, j＜m) are the Fourier transform results of j response point signal in measuring for the o time.

Can utilize principal component analysis (PCA) to find the solution transfer function matrix, transfer function matrix can be expressed as:

$H_{n\×m}\left(f\right)=U_r{D_r}^{1/2^{-1}}{Z_{\mathrm{Sr}}}^T{P}_{k\×m}\left(f\right)$

U wherein _rBe eigenvectors matrix, D _rBe diagonal matrix, Z _SrBe major component matrix, P _{K * m}(f) be response signal.

(6) the response point sound pressure variations situation of the synthetic whole process of giving it the gun:

Behind the transfer function matrix of obtaining each signal spacing, utilize a certain group of pumping signal, the corresponding response signal of synthetic calculating, the response sound pressure variations situation of process is thereby the whole vehicle that superposes out gives it the gun

$P\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}{P}_i\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(P_i\left(f\right)\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\left(f\right)\right)$

Wherein, P (t) is the response time-domain signal of the process of giving it the gun, P _i(t) be the response time-domain signal of i signal spacing, P _i(f) be the response frequency-region signal of i signal spacing, A _{I, n}(f) be the excitation frequency-region signal of i signal spacing, H _{I, n * m}(f) be the transfer function matrix of i signal spacing calculating according to top method

(7) utilize the give it the gun transfer function matrix of process of vehicle, can calculate each noise source, vibration source sensitivity and contribution degree the response point sound pressure signal.

The response point overall noise is to the sensitivity L of p noise source _Total(L _p-Δ) available following formula calculates

$L_{\mathrm{total}}(L_P-\mathrm{\Δ})=20{\log }_{10}\frac{\sqrt{\frac{\underset{t_1}{\overset{t_m}{\mathrm{\Σ}}}{\left[\mathrm{ifft}(\mathrm{fft}\left({\left[A\right|S]}^{\′\′}\left(t\right)\right)\·H\left(f\right))\right]}^2}{m}}}{p_0}$

P wherein ₀=210 ^-5Pa is a canonical reference pressure, the sound pressure level reduction of Δ for setting, the effective sound pressure of using when calculating sound pressure level, promptly in a certain period sampling time (from moment t ₁To t _m, amount to m sampled point) instantaneous sound pressure get root-mean-square value.[A|S] " sound pressure level L of p noise source of expression _nReduce the noise source signal matrix behind the Δ, promptly other noise source signals are constant, and only this noise source signal becomes original 10 ^-Δ/20Doubly:

[A|S]″＝[a ₁′，a ₂，…，10 ^-Δ/20·a _p，…，a _n]

In transfer function matrix and pumping signal, reject noise source or the vibration source that will analyze, response signal carried out The Fitting Calculation, thus can this noise source or vibration source to the contribution degree of response point sound pressure signal be:

${\mathrm{\γ}}_p=[1-\frac{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n-1}\left(t\right)H_{i,(n-1)\×(m-1)}\right)}{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\right)}]\×100\%$

A wherein _{I, n-1}(f) for rejecting the pumping signal of p noise source, H _{I, (n-1) * (m-1)}For rejecting the transmission signal matrix of p noise source.

Claims (1)

1. the Noise Sources Identification method of a vehicle acceleration noise is characterized in that this method may further comprise the steps:

(1) on tested vehicle, be provided for measuring the sound pressure signal of tested vehicle noise source, the vibration acceleration signal of vibration source and the sensor of tested vehicle vehicle speed signal v (t),

Two locating devices are placed on the acceleration start line and end of boost line of vehicle ' road respectively, are used to obtain the tested vehicle position signalling,

Two microphones are placed and two the corresponding vehicle ' road of locating device mid point both sides, are used to measure response point noise sound pressure signal,

Thermometer and wind gage are placed above-mentioned microphone next door, be used for measures ambient temperature and real-time wind speed;

(2) tested vehicle is travelled along the center line of vehicle ' road, the sensor before tested vehicle quickens, locating device, microphone is acquired signal simultaneously, when the front portion of tested vehicle arrives the acceleration start line of vehicle ' road, full throttle give it the gun by, when tested vehicle passes through the end of boost line, accelerator finishes, select a speed of a motor vehicle when giving it the gun the different speed of a motor vehicle of tested vehicle, tested vehicle is at the uniform velocity travelled on the vehicle ' road with this speed of a motor vehicle, the sound pressure signal of record tested vehicle noise source, the vibration acceleration signal of vibration source, vehicle speed signal, position signalling and response point noise sound pressure signal, select a plurality of different speed of a motor vehicle respectively, repeat at the uniform velocity to travel the sound pressure signal of record tested vehicle noise source, the vibration acceleration signal of vibration source, vehicle speed signal, position signalling and response point noise sound pressure signal;

(3) calculate tested vehicle in the particular moment of vehicle ' road driving process, the distance between tested vehicle and the above-mentioned microphone:

Wherein, v (t) is the speed of a motor vehicle of tested vehicle at t, t ₀Be the moment of tested vehicle by the acceleration start line, s ₀For quickening the distance between start line and the above-mentioned microphone, L is the distance of microphone to the vehicle ' road axis;

(4) according between above-mentioned vehicle speed signal v (t) and tested vehicle and the above-mentioned microphone apart from s (t), the sound pressure signal of microphone is handled, eliminate Doppler effect, process is as follows:

According to t constantly between tested vehicle and the above-mentioned microphone apart from s (t), calculate the time t that microphone is arrived in noise transmission that this moment tested vehicle sends _s:

$t_s=\frac{s\left(t\right)}{c}$

Wherein c is the velocity of sound at that time, and the noise of tested vehicle will be at t+t _sConstantly propagate into response point microphone place, utilize the time domain interpolation method that the sound pressure signal of above-mentioned microphone collection is converted into noise emission response point noise sound pressure signal constantly;

(5) from the moment t of tested vehicle by the acceleration start line ₀Beginning, tested vehicle is whenever travelled the vibration acceleration signal of sound pressure signal, vibration source of the noise source that setpoint distance write down and response point sound pressure signal as a signal spacing, obtains this signal spacing internal noise source and vibration source and be to the transfer function matrix H (f) of response point:

$H\left(f\right)=\left[h_i\left(f\right)\right]=\frac{p_i\left(f\right)}{a_i\left(f\right)}$

H wherein _i(f) be on the tested vehicle i noise source or vibration source to the transport function of response point, a _i(f) be i noise source or the noise sound pressure signal of vibration source or the Fourier transform results of vibration acceleration signal on the tested vehicle, p _i(f) be the Fourier transform results of the noise sound pressure signal that i noise source or vibration source produce in response point on the tested vehicle, repeating step (5) obtains the transfer function matrix H (f) in whole unlike signals interval;

(6) utilize the transfer function matrix H (f) in above-mentioned whole unlike signals interval, splice the give it the gun response acoustic pressure time-domain signal P (t) of process of tested vehicle and be:

$P\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}{P}_i\left(t\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(P_i\left(f\right)\right)=\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\left(f\right)\right)$

Wherein, P _i(t) be the response acoustic pressure time-domain signal of i signal spacing, P _i(f) be the response acoustic pressure frequency-region signal of i signal spacing, A _{I, n}(f) be the noise source sound pressure signal of i signal spacing and the frequency-region signal of vibration source vibration acceleration signal, H _{I, n * m}(f) be the transfer function matrix of i signal spacing calculating according to top method;

(7) utilize the give it the gun transfer function matrix of process of above-mentioned tested vehicle, calculate on the tested vehicle each noise source and vibration source to the sensitivity and the contribution degree of response point sound pressure signal:

The response point overall noise is to the sensitivity L of p noise source _Total(L _p-Δ) be:

$L_{\mathrm{total}}(L_p-\mathrm{\Δ})={20\log }_{10}\frac{\sqrt{\frac{\underset{t_1}{\overset{t_m}{\mathrm{\Σ}}}{\left[\mathrm{ifft}(\mathrm{fft}\left({\left[A\right|S]}^{\′\′}\left(t\right)\right)\·H\left(f\right))\right]}^2}{m}}}{p_0}$

P wherein ₀Be canonical reference pressure, m is a sampling number in the signal spacing, [A|S] " the sound pressure level Lp of p noise source of expression reduces the noise source signal matrix behind the Δ, the sound pressure level reduction of Δ for setting,

Noise source or vibration source to the contribution degree of response point sound pressure signal are:

${\mathrm{\γ}}_p=[1-\frac{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n-1}\left(f\right)H_{i,(n-1)\×(m-1)}\right)}{\underset{i=1}{\overset{k}{\mathrm{\Σ}}}\mathrm{ifft}\left(A_{i,n}\left(f\right)H_{i,n\×m}\right)}]\×100\%$

A wherein _{I, n-1}(f) be the remaining noise source sound pressure signal behind p noise source of rejecting or the vibration source and the frequency-region signal of vibration source vibration acceleration signal, H _{I, (n-1) * (m-1)}For rejecting the transfer function matrix behind p noise source or the vibration source.