A method for evaluating acoustic noise in passenger cars and a noise collection system

Abstract

A noise collection method, an evaluation method and a collection system for evaluating the acoustic noise inside a passenger car relate to the field of automobile audio testing. The method solves the problem that the test method using a standard sound source cannot directly measure and compare the sound pressure levels of fixed points inside and outside the car, and the consistency with the subjective evaluation results of automobile noise is poor. The noise collection method of the present invention comprises: obtaining vehicle information, the acoustic environment of the initial position point of the vehicle meets the requirements of GB / T 6882, and the ambient temperature is 20°C to 30°C; obtaining the position points of microphones inside and outside the vehicle; collecting the background noise inside the vehicle and adjusting the sound pressure level of the sound inside the vehicle; collecting the sound pressure level inside and outside the vehicle, and the collection time is 10 seconds; calculating the total sound pressure level difference of the microphones at each collection point according to the sound pressure level inside and outside the vehicle; and calculating the noise difference and the sound insulation rate according to the 1 / 3 octave. The present invention is suitable for detecting the field of automobile audio design.

Description

Technical Field

[0001] The invention relates to the field of automobile audio system testing, and in particular to a method for evaluating the impact of in-car audio sound on the external environment of the car. Background Art

[0002] When the car audio system is playing music, the sound inside the car will be transmitted to the outside through the car body. If the sound insulation performance of the car is not good and the sound leakage is too serious, it will greatly reduce the quality of the car, bring negative feelings to consumers, and cause after-sales complaints.

[0003] The existing technology generally tests the sound air transfer function inside and outside the vehicle to evaluate the sealing of the vehicle, replacing the vehicle's sound insulation ability with the sealing of the vehicle; or adopts a subjective evaluation method, where the evaluator stands at a fixed position outside the vehicle and uses his ears to feel the severity of the vehicle audio sound leakage to the outside of the vehicle.

[0004] The first method has the following three disadvantages: (1) The test method for the sound transfer function inside and outside the vehicle requires the use of a standard sound source. The standard sound source is a single sound source placed in a fixed position, while the audio system is a multi-source system formed by multiple speakers and subwoofers distributed in the vehicle. Even the sound frequencies played by each speaker are not the same, and the sound field formed in the vehicle is very complex. Using a single standard sound source cannot simulate the actual position and sound field effect of the audio system. (2) The speakers of the in-vehicle audio system are generally arranged in the middle of the vehicle dashboard, inside the door, C-pillar, A-pillar, floor, trunk and other parts, and are directly connected to the body parts. When the audio system is working, it will cause the surrounding parts to vibrate and radiate sound outward. This state is also impossible to simulate and restore with a single standard sound source. (3) The test method using a standard sound source cannot directly measure and compare the sound pressure levels at fixed points inside and outside the vehicle, and can only obtain the transfer function from inside to outside the vehicle.

[0005] The disadvantage of the second method is that each person has a different degree of perception of sound, the subjective evaluation results are inconsistent, and it is very easy to cause disputes. Summary of the invention

[0006] The invention solves the problems that the test method using a standard sound source cannot directly measure and compare the sound pressure levels of fixed points inside and outside the vehicle, and that the subjective evaluation of automobile audio noise has poor consistency and the results are difficult to reproduce.

[0007] A noise collection method for evaluating the acoustic noise in a passenger car, the collection method comprising:

[0008] Obtain vehicle information, wherein the acoustic environment of the initial position of the vehicle meets the requirements of GB / T 6882, and the ambient temperature is 20° C. to 30° C.;

[0009] Obtaining the microphone position points inside and outside the vehicle;

[0010] Collect the background noise inside the vehicle and adjust the sound pressure level of the in-vehicle audio system;

[0011] Collect the sound pressure level inside and outside the vehicle for 10 seconds;

[0012] Calculate the difference in total sound pressure level of the microphone at each collection point based on the sound pressure levels inside and outside the vehicle;

[0013] Noise difference and sound insulation rate are calculated based on 1 / 3 octave.

[0014] Further, the vehicle information is obtained:

[0015] Obtain the vehicle distance, wherein the front distance and rear distance of the vehicle are located in the semi-anechoic chamber, and the front distance and rear distance of the vehicle are greater than 2 meters from the front end of the semi-anechoic chamber wedge, and the side distance of the vehicle is greater than 2 meters from the front end of the semi-anechoic chamber wedge;

[0016] Obtaining vehicle equipment working information, wherein the engine, motor, communication, navigation system, air conditioner, wiper, heating system, and air conditioner fan inside the vehicle are in a closed state, and the doors, door windows, sunroof, and sunroof cover are in a closed state;

[0017] Acquiring tire position information, wherein the front and rear tires are both in a straight-line driving direction;

[0018] The seat position information is obtained, where the seat is located in a middle position horizontally and vertically, and the middle position is 45 degrees clockwise.

[0019] Further, the microphone position points inside and outside the vehicle are obtained, and the microphone position points are specifically:

[0020] The sensor IFL is located at the main driving position in the car, and the noise position collected by the sensor IFL is the collection point 1; the sensor IFR is located at the co-pilot position in the car, and the noise position collected by the sensor IFR is the collection point 2; the sensor IRL is located at the left side of the second row in the car, and the noise position collected by the sensor IRL is the collection point 3; the sensor IRR is located at the right side of the second row in the car, and the noise position collected by the sensor IRR is the collection point 4;

[0021] Sensor OFL is located at the outer door position of the main driver's car, and the noise position collected by the sensor OFL is collection point 5; sensor OFR is located at the outer door position of the co-driver's car, and the noise position collected by the sensor OFR is collection point 6; sensor ORL is located at the outer door position of the left side of the second row of the car, and the noise position collected by the sensor ORL is collection point 7; sensor ORR is located at the outer door position of the right side of the second row of the car, and the noise position collected by the sensor ORR is collection point 8.

[0022] Furthermore, the collecting of the vehicle interior background noise and adjusting the vehicle interior audio sound pressure level includes:

[0023] The duration of collecting the background noise signal is not less than 10s;

[0024] The specific method of adjusting the sound pressure level of the in-car audio system is as follows:

[0025] Access the pink noise signal;

[0026] The total sound pressure level of collection point 1 is collected by using the digital acquisition front end, and the total sound pressure level of collection point 1 is set to 80±1 dB (A).

[0027] Further, the calculation of the total sound pressure level difference of the microphones at each collection point includes:

[0028] The total sound pressure level difference between collection point 1 and collection point 5 is:

[0029] R1=L IFL -L OFL ;

[0030] The total sound pressure level difference between collection point 2 and collection point 6 is:

[0031] R2=L IFR -L OFR ;

[0032] The total sound pressure level difference between collection point 3 and collection point 7 is:

[0033] R3=L IRL -L ORL ;

[0034] The total sound pressure level difference between collection point 4 and collection point 8 is:

[0035] R4=L IRR -L OFL ;

[0036] Among them, L IFL is the total sound pressure level collected by the IFL microphone; L OFL L is the total sound pressure level collected by the microphone OFL; IFR is the total sound pressure level collected by the IFR microphone; LOFR is the total sound pressure level collected by the microphone of OFR; L IRR is the total sound pressure level collected by the IRR microphone; L OF is the total sound pressure level collected by the OFL microphone.

[0037] Furthermore, the noise difference calculation and sound insulation rate calculation based on the 1 / 3 octave band are specifically as follows:

[0038] The calculation method for the 1 / 3 octave noise difference between the acquisition points is:

[0039] The difference in the nth 1 / 3 octave noise between acquisition point 1 and acquisition point 5 is:

[0040] R （1，5）n =L IFL（n） -L OFL（n） ;

[0041] The difference in the nth 1 / 3 octave noise between acquisition point 2 and acquisition point 6 is:

[0042] R （2，6）n =L IFR（n） -L OFR（n） ;

[0043] The difference in the nth 1 / 3 octave noise between acquisition point 3 and acquisition point 7 is:

[0044] R （3，7）n =L IRL（n） -L ORL（n） ;

[0045] The difference in the nth 1 / 3 octave noise between acquisition point 4 and acquisition point 8 is:

[0046] R （4，8）n =L IRR（n） -L OFL（n） ;

[0047] The calculation method of sound insulation rate between collection points is:

[0048] The nth 1 / 3 octave sound insulation rate P of the collection point 1 and the collection point 5 （1，5）n =R （1，5）n / L IFL（n） ;

[0049] The nth 1 / 3 octave sound insulation rate P of the collection point 2 and the collection point 6 （2，6）n =R （2，6）n / L IFR（n） ;

[0050] The nth 1 / 3 octave sound insulation rate P of the sampling point 3 and the sampling point 7 （3，7）n =R （3，7）n / L IRL（n）;

[0051] The nth 1 / 3 octave sound insulation rate P of the collection point 4 and the collection point 8 （4，8）n =R （4，8）n / L IRR（n） ;

[0052] Where n is the 1 / 3 octave number; L IFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFL; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL; L IFR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFR; L OFR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFR; L IRR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IRR; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL.

[0053] The present invention also provides a method for evaluating the acoustic noise in a passenger car. The method is implemented based on data obtained by any one of the noise collection methods described above. The method comprises:

[0054] Evaluate the total sound pressure level difference of the microphones at each measurement point and perform FFT frequency domain analysis;

[0055] The total sound pressure level difference limit of the microphones at each measuring point is 40 dB (A). If the noise difference at a pair of measuring points is greater than 40 dB (A), it is judged that the sound insulation capacity of the vehicle body at this point is good; if the noise difference at a corresponding measuring point is less than 40 dB (A), it is judged that the sound insulation capacity of the vehicle body at this point is poor.

[0056] The present invention also provides a noise collection system for evaluating the acoustic noise in a passenger car. The system is implemented based on the collection method in the method for evaluating the acoustic noise in a passenger car according to claim 1. The system comprises:

[0057] a plurality of internal microphones, a plurality of external microphones, a signal processing device and a data transmission unit;

[0058] The multiple internal microphones are respectively located at collection point 1, collection point 2, collection point 3 and collection point 4, and are used to obtain audio signals inside the vehicle;

[0059] The plurality of external microphones are respectively located at collection point 5, collection point 6, collection point 7 and collection point 8, and are used to obtain external audio signals of the vehicle;

[0060] The data transmission unit is used to send the noise signals collected by all sensors to the signal processing device;

[0061] The signal processing device is used to receive the audio signals collected by all sensors, and is also used to calculate the in-vehicle audio sound pressure level based on collection points 1, 2, 3 and 4; it is also used to calculate the total sound pressure level difference of the microphones at each collection point based on the sound pressure levels inside and outside the vehicle; it is also used to calculate the noise difference and sound insulation rate based on 1 / 3 octave.

[0062] Furthermore, the microphone is calibrated using a Class 1 sound calibrator that complies with GB / T 15173.

[0063] Furthermore, the microphone used for collecting noise meets the requirements of Type 1 instrument specified in GB 3785.1, and the frequency range covers at least the frequency range of 10 Hz to 20480 Hz.

[0064] The advantages of the present invention are:

[0065] (1) Microphones are placed at specific locations inside and outside the vehicle, and the difference in total sound pressure level and 1 / 3 octave sound insulation rate of the noise measured by the microphone inside and outside the vehicle are calculated to evaluate the impact of the in-vehicle audio sound on the outside environment. By comparing the actual calculation with the limit of the total sound pressure level difference, it can be concluded that the greater the difference in total sound pressure level of the noise at a certain location exceeds the limit, the better the sound insulation performance here, that is, the smaller the impact of the audio sound on the outside environment of the vehicle. For the area near a fixed measuring point, the lower the 1 / 3 octave sound insulation rate obtained by the above method, the more serious the impact of the audio sound on the outside of the vehicle in this 1 / 3 octave. This method can not only locate the location of the vehicle sound leakage, but also determine the sound leakage frequency, which helps engineers to solve the leakage problem in a targeted manner.

[0066] (2) The advantage of the present invention is that it uses an audio signal to directly drive the sound system to make sound. The sound source comes from the various speakers of the sound system. Its sound and vibration state are completely consistent with the state of the user's daily use of the vehicle sound system to play programs, and can truly reflect the impact of the sound of the in-car sound on the outside environment. For the existing technology, standard sound sources are used when simulating sound. However, standard sound sources can only make sounds at any fixed position, which is different from the sound of the in-car sound, and cannot simulate the actual position and sound field effect of the sound system. The present invention uses standard pink noise as an audio signal, and utilizes the characteristic that the intensity of pink noise is equal in each octave, which is more in line with the auditory habits of the human ear, while ensuring comprehensive coverage of the human ear's auditory sensitive frequencies.

[0067] (3) The present invention overcomes the disadvantage that the subjective evaluation results are discrete and easily controversial. By evaluating the total sound pressure level difference of the microphones at each measuring point and performing an objective test through FFT frequency domain analysis and combining the results to calculate an objective value, the present invention overcomes the disadvantage that the subjective evaluation results are discrete and easily controversial.

[0068] (4) The present invention adopts an objective testing method, which can more easily achieve objective evaluation results comparison of different vehicles.

[0069] (5) The present invention can determine the leakage position and leakage frequency of vehicle audio relatively accurately, which is conducive to targeted problem improvement.

[0070] (6) By using this method to accumulate a large number of test and evaluation results, a database can be formed. By conducting statistical analysis on the database, it is possible to formulate sound insulation rate limit standards that meet the company's own needs and use them to guide vehicle design and development.

[0071] The invention is applicable to the field of automobile audio design. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 A flow chart of the method for evaluating the impact of in-vehicle audio sound on the external environment of the vehicle according to the present invention;

[0073] Figure 2 A schematic diagram of the position of a vehicle in a semi-anechoic chamber according to the second embodiment of the present invention;

[0074] Figure 3 The positions and names of the eight microphones inside and outside the vehicle according to the third embodiment of the present invention;

[0075] Figure 4 This is a schematic diagram of the position of seats in a vehicle and the distance position of microphones according to the third embodiment of the present invention;

[0076] Figure 5 This is a schematic diagram of the positions of four microphones near the exterior door of a vehicle according to the third embodiment of the present invention;

[0077] Figure 6 This is a schematic diagram of the test output spectrum described in Example 6 of the present invention. DETAILED DESCRIPTION

[0078] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0079] Embodiment 1: A noise collection method for evaluating the acoustic noise in a passenger car according to this embodiment includes:

[0080] Obtain vehicle information, wherein the acoustic environment of the initial position of the vehicle meets the requirements of GB / T 6882, and the ambient temperature is 20° C. to 30° C.;

[0081] Obtaining the microphone position points inside and outside the vehicle;

[0082] Collect the background noise inside the vehicle and adjust the sound pressure level of the in-vehicle audio system;

[0083] Collect the sound pressure level inside and outside the vehicle for 10 seconds;

[0084] Calculate the difference in total sound pressure level of the microphone at each collection point based on the sound pressure levels inside and outside the vehicle;

[0085] Noise difference and sound insulation rate are calculated based on 1 / 3 octave.

[0086] The method described in this embodiment can objectively evaluate the location of sound leakage, which is used for noise assessment and is convenient for engineers to improve and compare the sound.

[0087] Example 2, see Figure 2 This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car described in the first embodiment, wherein the vehicle information is obtained:

[0088] Obtain the vehicle distance, wherein the front distance and rear distance of the vehicle are located in the semi-anechoic chamber, and the front distance and rear distance of the vehicle are greater than 2 meters from the front end of the semi-anechoic chamber wedge, and the side distance of the vehicle is greater than 2 meters from the front end of the semi-anechoic chamber wedge;

[0089] Obtaining vehicle equipment working information, wherein the engine, motor, communication, navigation system, air conditioner, wiper, heating system, and air conditioner fan inside the vehicle are in a closed state, and the doors, door windows, sunroof, and sunroof cover are in a closed state;

[0090] Acquiring tire position information, wherein the front and rear tires are both in a straight-line driving direction;

[0091] The seat position information is obtained, where the seat is located in a middle position horizontally and vertically, and the middle position is 45 degrees clockwise.

[0092] In this embodiment, the adjustable headrest located on the seat should be in the middle position.

[0093] Example 3, see Figure 3 , Figure 4 and Figure 5 This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car according to the first embodiment, wherein the microphone positions inside and outside the vehicle are obtained, and the microphone positions are specifically:

[0094] The sensor IFL is located at the main driving position in the car, and the noise position collected by the sensor IFL is the collection point 1; the sensor IFR is located at the co-pilot position in the car, and the noise position collected by the sensor IFR is the collection point 2; the sensor IRL is located at the left side of the second row in the car, and the noise position collected by the sensor IRL is the collection point 3; the sensor IRR is located at the right side of the second row in the car, and the noise position collected by the sensor IRR is the collection point 4;

[0095] Sensor OFL is located at the outer door position of the main driver's car, and the noise position collected by the sensor OFL is collection point 5; sensor OFR is located at the outer door position of the co-driver's car, and the noise position collected by the sensor OFR is collection point 6; sensor ORL is located at the outer door position of the left side of the second row of the car, and the noise position collected by the sensor ORL is collection point 7; sensor ORR is located at the outer door position of the right side of the second row of the car, and the noise position collected by the sensor ORR is collection point 8.

[0096] In this embodiment, as shown in Figure 4, the seat height is in the range of 0.95m to 1.05m. Figure 5 As shown in the figure, the sensor is 1.6m away from the ground. Figure 3 As shown in the figure, the four sensor collection points inside the vehicle are located on the seat headrest near the window. This position is near the passenger's ear, and the sound pressure level test result can represent the sound pressure level near the passenger's ear. At the same time, the position near the window in the car enables it to fully receive the sound from the door and the speaker placed at the A-pillar on the same side, making the signal-to-noise ratio of the test result higher.

[0097] Embodiment 4: This embodiment is a noise collection method for evaluating the in-vehicle acoustic noise of a passenger car described in Embodiment 1. The method of collecting the vehicle interior background noise and adjusting the in-vehicle acoustic sound pressure level includes:

[0098] The duration of collecting the background noise signal is not less than 10s;

[0099] The specific method of adjusting the sound pressure level of the in-car audio system is as follows:

[0100] Access the pink noise signal;

[0101] The total sound pressure level of collection point 1 is collected by using the digital acquisition front end, and the total sound pressure level of collection point 1 is set to 80±1 dB (A).

[0102] In actual applications, it should be checked and confirmed that all collection points in the vehicle are within the frequency range of 20Hz-20000Hz, and the 1 / 3 octave sound pressure level of each collection point is greater than the background noise at the measurement point by more than 10dB (A).

[0103] Embodiment 5: This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car according to Embodiment 1. The method of calculating the difference in the total sound pressure level of the microphones at each collection point includes:

[0104] The total sound pressure level difference between collection point 1 and collection point 5 is:

[0105] R1=L IFL -L OFL； ;

[0106] The total sound pressure level difference between collection point 2 and collection point 6 is:

[0107] R2=L IFR -L OFR ;

[0108] The total sound pressure level difference between collection point 3 and collection point 7 is:

[0109] R3=L IRL -L ORL ;

[0110] The total sound pressure level difference between collection point 4 and collection point 8 is:

[0111] R4=L IRR -L OFL ;

[0112] Among them, L IFL is the total sound pressure level collected by the IFL microphone; L OFL L is the total sound pressure level collected by the microphone OFL; IFR is the total sound pressure level collected by the IFR microphone; L OFR is the total sound pressure level collected by the microphone of OFR; L IRR is the total sound pressure level collected by the IRR microphone; L OF is the total sound pressure level collected by the OFL microphone.

[0113] Example 6, see Figure 6 This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car described in the first embodiment, wherein the noise difference calculation and the sound insulation rate calculation are performed based on the 1 / 3 octave band, specifically:

[0114] Each 1 / 3 octave of the test frequency band is numbered from 1 to 32, as shown in Table 1:

[0115] Table 1 1 / 3 octave center frequencies and numbers

[0116]

[0117] The difference in the nth 1 / 3 octave noise between acquisition point 1 and acquisition point 5 is:

[0118] R （1，5）n =L IFL（n） -L OFL（n） ;

[0119] The difference in the nth 1 / 3 octave noise between acquisition point 2 and acquisition point 6 is:

[0120] R （2，6）n =L IFR（n） -L OFR（n） ;

[0121] The difference in the nth 1 / 3 octave noise between acquisition point 3 and acquisition point 7 is:

[0122] R （3，7）n =L IRL（n） -L ORL（n） ;

[0123] The difference in the nth 1 / 3 octave noise between acquisition point 4 and acquisition point 8 is:

[0124] R （4，8）n =L IRR（n） -L OFL（n） ;

[0125] The calculation method of sound insulation rate between collection points is:

[0126] The nth 1 / 3 octave sound insulation rate P of the collection point 1 and the collection point 5 （1，5）n =R （1，5）n / L IFL（n） ;

[0127] The nth 1 / 3 octave sound insulation rate P of the collection point 2 and the collection point 6 （2，6）n =R （2，6）n / L IFR（n） ;

[0128] The nth 1 / 3 octave sound insulation rate P of the sampling point 3 and the sampling point 7 （3，7）n =R （3，7）n / L IRL（n） ;

[0129] The nth 1 / 3 octave sound insulation rate P of the collection point 4 and the collection point 8 （4，8）n =R （4，8）n / L IRR（n） ;

[0130] Where n is the 1 / 3 octave number; L IFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFL; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL; L IFR（n）The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFR; L OFR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFR; L IRR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IRR; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL.

[0131] In this embodiment, the impact of the in-car audio sound on the external environment is evaluated as follows: if the total sound pressure level noise difference near a certain measuring point is larger, it means that the impact of the in-car audio sound on the external environment at this point is smaller.

[0132] For a certain pair of measuring points, the lower the sound insulation rate of the nth 1 / 3 octave band, the greater the impact of the in-car audio sound on the external environment within this 1 / 3 octave band.

[0133] The sound insulation rate limit values ​​for each 1 / 3 octave frequency band are set as shown in Table 2. Compare the calculated results with the limit values. If the sound insulation rate of a 1 / 3 octave frequency band of a pair of measurement points is lower than the limit value, the evaluation result is unqualified.

[0134] Table 2 Sound insulation rate limits for each 1 / 3 octave frequency band

[0135]

[0136] Embodiment 7: A method for evaluating the acoustic noise in a passenger car described in this embodiment is implemented based on data obtained by the noise collection method described in any one of the above embodiments, and the evaluation method includes:

[0137] Evaluate the total sound pressure level difference of the microphones at each measurement point and perform FFT frequency domain analysis;

[0138] The total sound pressure level difference limit of the microphones at each measuring point is 40 dB (A). If the noise difference at a pair of measuring points is greater than 40 dB (A), it is judged that the sound insulation capacity of the vehicle body at this point is good; if the noise difference at a corresponding measuring point is less than 40 dB (A), it is judged that the sound insulation capacity of the vehicle body at this point is poor.

[0139] Embodiment 8: A noise collection system for evaluating the acoustic noise in a passenger car according to this embodiment, the system comprises:

[0140] a plurality of internal microphones, a plurality of external microphones, a signal processing device and a data transmission unit;

[0141] The multiple internal microphones are respectively located at collection point 1, collection point 2, collection point 3 and collection point 4, and are used to obtain audio signals inside the vehicle;

[0142] The plurality of external microphones are respectively located at collection point 5, collection point 6, collection point 7 and collection point 8, and are used to acquire audio signals outside the vehicle;

[0143] The data transmission unit is used to send the noise signals collected by all sensors to the signal processing device;

[0144] The signal processing device is used to receive the audio signals collected by all sensors, and is also used to calculate the in-vehicle audio sound pressure level based on collection points 1, 2, 3 and 4; it is also used to calculate the total sound pressure level difference of the microphones at each collection point based on the sound pressure levels inside and outside the vehicle; it is also used to calculate the noise difference and sound insulation rate based on 1 / 3 octave.

[0145] Embodiment 9: This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car described in Embodiment 1. The microphone is calibrated using a Class 1 sound calibrator that complies with GB / T 15173.

[0146] In this embodiment, a Class 1 acoustic calibrator is used for calibration to minimize the generator frequency error. Without any adjustment, the deviation between the two calibrations does not exceed 0.5 dB (A). The sampling frequency of the data acquisition system is set to 20480 Hz, and the A / D conversion resolution is 24 bits.

[0147] Embodiment 10: This embodiment is a noise collection method for evaluating the acoustic noise in a passenger car described in Embodiment 1. The microphone used for collecting the noise meets the requirements of a Type 1 instrument specified in GB 3785.1, and the frequency range covers at least a frequency range of 10 Hz to 20480 Hz.

Claims

1. A method for evaluating acoustic noise in a passenger car, characterized in that: The evaluation method is implemented by data obtained by the noise collection method, and the evaluation method includes: Evaluate the total sound pressure level difference of the microphones at each measurement point and perform FFT frequency domain analysis; The total sound pressure level difference limit of the microphones at each measuring point is 40 dB (A). If the noise difference at a pair of measuring points is greater than 40 dB (A), it is determined that the sound insulation capacity of the vehicle body at this point is good; if the noise difference at a corresponding measuring point is less than 40 dB (A), it is determined that the sound insulation capacity of the vehicle body at this point is poor; The collection method comprises: Obtain vehicle information, wherein the acoustic environment of the initial position of the vehicle meets the requirements of GB / T 6882, and the ambient temperature is 20° C. to 30° C.; Obtaining the microphone position points inside and outside the vehicle; Collect the background noise inside the vehicle and adjust the sound pressure level of the in-vehicle audio system; Collect the sound pressure level inside and outside the vehicle for 10 seconds; Calculate the difference in total sound pressure level of the microphone at each collection point based on the sound pressure levels inside and outside the vehicle; Calculate the noise difference and sound insulation rate based on 1 / 3 octave; The microphone position points are specifically: The sensor IFL is located at the main driving position in the car, and the noise position collected by the sensor IFL is the collection point 1; the sensor IFR is located at the co-pilot position in the car, and the noise position collected by the sensor IFR is the collection point 2; the sensor IRL is located at the left side of the second row in the car, and the noise position collected by the sensor IRL is the collection point 3; the sensor IRR is located at the right side of the second row in the car, and the noise position collected by the sensor IRR is the collection point 4; The sensor OFL is located at the outer door of the main driver's car, and the noise position collected by the sensor OFL is the collection point 5; the sensor OFR is located at the outer door of the co-driver's car, and the noise position collected by the sensor OFR is the collection point 6; the sensor ORL is located at the outer door of the left side of the second row, and the noise position collected by the sensor ORL is the collection point 7; the sensor ORR is located at the outer door of the right side of the second row, and the noise position collected by the sensor ORR is the collection point 8; The noise difference calculation and sound insulation rate calculation based on 1 / 3 octave are specifically as follows: The calculation method for the 1 / 3 octave noise difference between the acquisition points is: The difference in the nth 1 / 3 octave noise between acquisition point 1 and acquisition point 5 is: R （1，5）n =L IFL（n） -L OFL（n） ; The difference in the nth 1 / 3 octave noise between acquisition point 2 and acquisition point 6 is: R （2，6）n =L IFR（n） -L OFR（n） ; The difference in the nth 1 / 3 octave noise between acquisition point 3 and acquisition point 7 is: R （3，7）n =L IRL（n） -L ORL（n） ; The difference in the nth 1 / 3 octave noise between acquisition point 4 and acquisition point 8 is: R （4，8）n =L IRR（n） -L OFL（n） ; The calculation method of sound insulation rate between collection points is: The nth 1 / 3 octave sound insulation rate P of the collection point 1 and the collection point 5 （1，5）n =R （1，5）n / L IFL（n） ; The nth 1 / 3 octave sound insulation rate P of the collection point 2 and the collection point 6 （2，6）n =R （2，6）n / L IFR（n） ; The nth 1 / 3 octave sound insulation rate P of the sampling point 3 and the sampling point 7 （3，7）n =R （3，7）n / L IRL（n） ; The nth 1 / 3 octave sound insulation rate P of the collection point 4 and the collection point 8 （4，8）n =R （4，8）n / L IRR（n） ; Where n is the 1 / 3 octave number; L IFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFL; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL; L IFR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IFR; L OFR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFR; L IRR（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone IRR; L OFL（n） The sound pressure level of the nth 1 / 3 octave band collected by the microphone OFL; The collecting of the vehicle interior background noise and adjusting the vehicle interior audio sound pressure level comprises: The duration of collecting the background noise signal is not less than 10s; The specific method of adjusting the sound pressure level of the in-car audio system is as follows: Access the pink noise signal; The total sound pressure level of collection point 1 is collected by using the digital acquisition front end, and the total sound pressure level of collection point 1 is set to 80±1 dB (A).

2. A passenger car interior acoustic noise evaluation method according to claim 1, characterized in that: Obtaining vehicle information: Obtain the vehicle distance, wherein the front distance and rear distance of the vehicle are located in the semi-anechoic chamber, and the front distance and rear distance of the vehicle are greater than 2 meters from the front end of the semi-anechoic chamber wedge, and the side distance of the vehicle is greater than 2 meters from the front end of the semi-anechoic chamber wedge; Obtaining vehicle equipment working information, wherein the engine, motor, communication, navigation system, air conditioner, wiper, heating system, and air conditioner fan inside the vehicle are in a closed state, and the doors, door windows, sunroof, and sunroof cover are in a closed state; Get tire position information, the front and rear tires are in a straight-line driving direction; The seat position information is obtained, where the seat is located in a middle position horizontally and vertically, and the middle position is 45 degrees clockwise.

3. The method for evaluating the acoustic noise in a passenger car according to claim 1, characterized in that: The calculating of the total sound pressure level difference of the microphones at each collection point includes: The total sound pressure level difference between collection point 1 and collection point 5 is: R1=L IFL -L OFL ; The total sound pressure level difference between collection point 2 and collection point 6 is: R2=L IFR -L OFR ; The total sound pressure level difference between collection point 3 and collection point 7 is: R3=L IRL -IT ORL ; The total sound pressure level difference between collection point 4 and collection point 8 is: R4=L IRR -L OFL ; Among them, L IFL is the total sound pressure level collected by the microphone of IFL; L OFL L is the total sound pressure level collected by the microphone OFL; IFR is the total sound pressure level collected by the IFR microphone; L OFR is the total sound pressure level collected by the microphone of OFR; L IRR is the total sound pressure level collected by the IRR microphone; L OF is the total sound pressure level collected by the OFL microphone.

4. The method for evaluating the acoustic noise in a passenger car according to claim 1, characterized in that: The microphone is calibrated using a Class 1 sound calibrator that complies with GB / T 15173.

5. The method for evaluating the acoustic noise in a passenger car according to claim 4, characterized in that: The microphone meets the requirements of Type 1 instrument specified in GB 3785.1, and the frequency range covers at least the frequency range of 10 Hz to 20480 Hz.

6. A noise collection system for evaluating the acoustic noise in a passenger car, characterized in that: The system is implemented based on the acquisition method in the method for evaluating the in-vehicle acoustic noise of a passenger car according to claim 1, and the system comprises: a plurality of internal microphones, a plurality of external microphones, a signal processing device and a data transmission unit; The multiple internal microphones are respectively located at collection point 1, collection point 2, collection point 3 and collection point 4, and are used to obtain audio signals inside the vehicle; The plurality of external microphones are respectively located at collection point 5, collection point 6, collection point 7 and collection point 8, and are used to obtain external audio signals of the vehicle; The data transmission unit is used to send the noise signals collected by all sensors to the signal processing device; The signal processing device is used to receive the audio signals collected by all sensors, and is also used to calculate the in-vehicle audio sound pressure level based on collection points 1, 2, 3 and 4; it is also used to calculate the total sound pressure level difference of the microphones at each collection point based on the sound pressure levels inside and outside the vehicle; it is also used to calculate the noise difference and sound insulation rate based on 1 / 3 octave.

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