阅读说明：本技术 一种空调通风噪音计算的系统和方法 (System and method for calculating ventilation noise of air conditioner ) 是由 朱波 陈旺才 田德旺 沈鲲 王新 赖选华 于 2021-06-28 设计创作，主要内容包括：本发明公开了一种空调通风噪音计算的系统和方法,包括：分别测量多个设定模式的多档位下的空调总风量值Q-(i)和对应风量下的通风噪音声压级L-(i)；通过线性拟合计算得出所述总风量值Q-(i)和风量为Q-(i)时各个频率f-(j)下通风噪音声压级的函数关系中的斜率和常数对各频率下的噪音值进行叠加计算得到人耳处的总声压级L-(i)。利用本发明所述的方法可快速计算任何风量下的人耳处的噪音,也可通过测量人耳处的噪音值计算出总风量,从而找到兼顾热性能和声学性能的最优风量值,便捷确定空调风量标定软件策略；还可对不同车辆的空调通风噪音进行对标,针对不同车型计算固定风量下的噪音并对比,排除软件对噪音的影响,更好地对硬件性能进行对比。(The invention discloses a system and a method for calculating ventilation noise of an air conditioner, which comprises the following steps: respectively measuring the total air volume Q of the air conditioner under multiple gears of multiple setting modes i And the sound pressure level L of the ventilation noise under the corresponding air quantity i (ii) a Calculating the total air quantity value Q through linear fitting i The sum air volume is Q i Time of each frequency f j Lower ventilation noise sound pressure level Slope in the functional relationship of Sum constant The noise values under all frequencies are superposed and calculated to obtain the total sound pressure level L of the human ear i . The method can quickly calculate the noise at the ear under any air quantity, and can also calculate the total air quantity by measuring the noise value at the ear, thereby finding the optimal air quantity value with both thermal performance and acoustic performance and conveniently determining the air-conditioning air quantity calibration software strategy; still can carry out the benchmarking to the air conditioner ventilation noise of different vehicles, calculate the noise and the contrast under the fixed amount of wind to different motorcycle types, get rid of the influence of software to the noise, compare the hardware performance better.)

1. A method for calculating the ventilation noise of air conditioner features that the total air volume Q of air conditioner in multiple gears of multiple setting modes is measured_iAnd the sound pressure level L of the ventilation noise under the corresponding air quantity_i(ii) a Calculating the total air quantity value Q through linear fitting_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantThe noise values under all frequencies are superposed and calculated to obtain the total sound pressure level L of the human ear_i。

2. The method for calculating the ventilation noise of the air conditioner according to claim 1, wherein the noise sound pressure level at the human ear and the logarithm of the total air volume Q of the air conditioner box are in a linear relationship.

3. The method of calculating the ventilation noise of an air conditioner of claim 1, further comprising measuring the background noise sound pressure level.

4. The method for calculating the ventilation noise of the air conditioner according to claim 3, further comprising selecting the total air volume value of the air conditioner and the noise sound pressure level at the corresponding air volume, in which the sound pressure difference between the ventilation noise and the background noise at a plurality of gears of a plurality of setting modes is greater than a set value, to perform the linear fitting calculation.

5. The method of claim 1, wherein the total air volume Q is calculated by linear fitting_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantThe method also comprises the steps of carrying out Fourier transform on the noise measurement result at the ear of a human body to obtain a 1/n octave frequency spectrum result, and carrying out linear fitting on the sound pressure level and the air quantity value of the ventilation noise under each frequency of the 1/n octave frequency spectrum result to obtain a slopeSum constant

6. The method of claim 1, wherein the total air volume value Q is calculated by linear fitting_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantLater, the noise value at the human ear can be measured, and the slope can be measuredSum constantAnd substituting to obtain the corresponding total air volume value of the air conditioner.

7. A system for calculating ventilation noise of an air conditioner, comprising: the air quantity measuring module is used for measuring the total air quantity under a plurality of gears of a plurality of setting modes; human ear noise measurement module: the noise meter is used for measuring noise values of human ears under a plurality of gears of a plurality of setting modes; a parameter calculation module: function parameter values for calculating ventilation noise sound pressure level and air volume value; a noise calculation module: the device is used for calculating noise values of human ears under different air quantities; and the noise comparison module is used for comparing the sound pressure level difference of the ventilation noise and the background noise under a plurality of working conditions.

8. The system for air conditioner ventilation noise calculation of claim 7, further comprising a background noise measurement module for measuring background noise at a plurality of gears of a plurality of settings modes.

9. The system for calculating ventilation noise of an air conditioner according to claim 7, further comprising a total air volume calculating module for calculating a total air volume value at a plurality of gears of a plurality of setting modes.

10. The system for air conditioning ventilation noise calculation of claim 7, wherein the parameter calculation module further comprises a frequency interval spectrum calculation module: carrying out Fourier transform on the noise measurement result of the human ear to obtain a 1/n octave frequency spectrum result; a linear fitting calculation module: performing linear fitting on the plurality of ventilation noise sound pressure levels and the air volume values to obtain function parameter values of the ventilation noise sound pressure levels and the air volume values: slope ofSum constant

Technical Field

The invention belongs to the technical field of noise calculation, and particularly relates to a system and a method for calculating ventilation noise of an air conditioner.

Background

With the development of the automobile industry, the requirement of customers on the comfort of automobiles is higher, wherein the noise of an air conditioner is one of the complaints of customers, the first five complaints of all customers are ranked, and three fourths of the complaints of the noise of the air conditioner are the ventilation noise of the air conditioner, so the calculation and analysis of the ventilation noise of the air conditioner are particularly important.

The ventilation of the air conditioner refers to the whole process that outside air passes through a firewall channel from an air inlet, enters a ventilation pipe from an air conditioning box through the excitation of a blower, then enters a passenger compartment from an air outlet of an instrument board and finally is discharged out of the vehicle through an air outlet. The ventilation noise of the air conditioner is noise generated during ventilation. The ventilation noise is aerodynamic acoustic, and is mainly caused by unstable airflow pressure on the rigid surface of the ventilation system or turbulent impact on the physical surface, and then the aerodynamic noise is generated.

At present, a calculation method for the aerodynamic noise of the air conditioner is mainly based on fluid mechanics calculation software to calculate and analyze a flow field in a ventilation pipeline, the number of finite element grids is huge, and a large amount of calculation resources and time are consumed. In addition, for the sound actually heard by human ears, no effective method is available for calculation, and researches are made on obtaining a pipeline sound source firstly by adopting fluid mechanics calculation and then calculating the noise in the vehicle by a statistical energy method, so that the total sound pressure level can only be calculated approximately, a spectrogram cannot be obtained, and the precision is limited.

Disclosure of Invention

The invention aims to provide a method for calculating ventilation noise of an air conditioner,

the technical scheme of the method for calculating the ventilation noise of the air conditioner, which is one of the purposes of the invention, is as follows: respectively measuring the total air volume value Q of the air conditioner under a plurality of gears under a plurality of setting modes_iAnd the sound pressure level L of the ventilation noise under the corresponding air quantity_i(ii) a Calculating the total air quantity value Q through linear fitting_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantThe noise values under all frequencies are superposed and calculated to obtain the total sound pressure level L of the human ear_i。

The plurality of setting modes are modes set by an air conditioner, such as a full-cold blowing surface outer circulation mode; the plurality of gears are corresponding air volume gears in each mode.

Measuring the total air inlet air quantity Q of the air conditioner at each gear of each mode on an air quantity rack, and then measuring the steady state noise values at the positions of the ears corresponding to the modes and the gears to obtain the steady state noise values at the positions of the ears corresponding to n groups of different air quantities; the logarithm of the noise sound pressure level at the ear and the total air volume of the air conditioning box can be known to form a linear relation through deduction; therefore, parameters corresponding to the linear relation can be calculated by carrying out linear fitting calculation on the steady-state noise values of the corresponding human ears under n groups of different air quantities; then, the noise values under all frequencies are subjected to superposition calculation to obtainTotal sound pressure level L at the human ear_i。

The further technical scheme comprises the following steps: the noise sound pressure level of the human ear and the logarithm of the total air quantity Q of the air-conditioning box are in linear relation.

The further technical scheme comprises the following steps: a measurement of background noise sound pressure level is also included.

The further technical scheme comprises the following steps: and selecting the total air volume value of the air conditioner and the noise sound pressure level of the corresponding air volume, wherein the sound pressure difference value between the ventilation noise and the background noise under each gear of each set mode is greater than a set value, and performing linear fitting calculation to ensure that the calculation result is more accurate.

The further technical scheme comprises the following steps: the total air quantity value Q is obtained through linear fitting calculation_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantThe method also comprises the steps of carrying out Fourier transform on the noise measurement result at the ear of a human body to obtain a 1/n octave frequency spectrum result, and carrying out linear fitting on the sound pressure level and the air quantity value of the ventilation noise under each frequency of the 1/n octave frequency spectrum result to obtain a slopeSum constant

The further technical scheme comprises the following steps: calculating the total air quantity value Q through linear fitting_iThe sum air volume is Q_iTime of each frequency f_jLower ventilation noise sound pressure levelSlope in the functional relationship ofSum constantLater, the noise value at the human ear can be measured, and the slope can be measuredSum constantAnd substituting to obtain the corresponding total air volume value of the air conditioner.

The system for calculating ventilation noise of an air conditioner, which realizes the second object of the invention, comprises: the air quantity measuring module is used for measuring the total air quantity under each gear of each set mode; human ear noise measurement module: the noise value measuring device is used for measuring the noise value of the human ear under each gear of each set mode; a parameter calculation module: function parameter values for calculating ventilation noise sound pressure level and air volume value; a noise calculation module: the noise value calculation module is used for calculating the noise value of the ear under different air quantities; and the noise comparison module is used for comparing the difference of the sound pressure levels of the ventilation noise and the background noise under each working condition.

The further technical scheme comprises the following steps: the system also comprises a background noise calculation module for measuring the background noise under each gear of each set mode.

The background noise refers to noise when the air conditioner is not turned on, such as engine noise, ambient noise, and noise at vehicle idle speed. The background noise can be tested in real time and can also be calibrated in advance aiming at each set mode. If the background noise is too high, the results of the ventilation noise measurement will be affected and not accurate enough.

The further technical scheme comprises the following steps: the system also comprises a total air quantity calculating module which is used for calculating the total air quantity value under each gear of each setting mode.

The method of the invention can calculate the linear relation between the noise value at the human ear and the total air volume of the air conditioner, thereby calculating the total air volume value of the corresponding air conditioner by measuring the noise value at the human ear under each gear of each set mode in a reverse-deducing way.

The further technical scheme comprises the following steps: the parameter calculation module further comprises a frequency interval spectrum calculation module: carrying out Fourier transform on the noise measurement result of the human ear to obtain a 1/n octave frequency spectrum result; a linear push calculation module: performing linear fitting on the plurality of ventilation noise sound pressure levels and the air volume values to obtain function parameter values of the ventilation noise sound pressure levels and the air volume values: slope ofSum constant

By utilizing the method, the noise at the ear under any air volume can be quickly calculated, and the total air volume can also be calculated by measuring the noise value at the ear, so that the heat comfort performance and the acoustic comfort performance of the cabin can be converged, the optimal air volume value which can ensure that both the heat performance and the acoustic performance can be considered can be found, and the air volume calibration software strategy of the air conditioner can be quickly and conveniently determined; meanwhile, the calibration can be better carried out on the ventilation noise of air conditioners of different vehicles, the noise under a certain fixed air volume can be calculated and compared for different vehicle types, so that the influence of software on the noise is eliminated, and the hardware performance is better compared.

Drawings

FIG. 1 is a flow chart of the calculations described in the present invention;

FIG. 2 is a comparison of ventilation noise and test results calculated using the method of the present invention for a vehicle model.

Detailed Description

The following detailed description is provided for the purpose of explaining the claimed embodiments of the present invention so that those skilled in the art can understand the claims. The scope of the invention is not limited to the following specific implementation configurations. It is intended that the scope of the invention be determined by those skilled in the art from the following detailed description, which includes claims that are directed to this invention.

The sound at the ear of the person in the vehicle is not only related to the sound source at the pipeline, but also related to sound absorption and insulation on the transmission path in the cabin.

Where the sound source is aerodynamic noise, it can be analogized to monopole, dipole and quadrupole sound sources. The monopole sound source sound power is proportional to the airflow velocity to the power of 4:

in the formula W₁Acoustic power, p, for a monopole sound source₀Is the fluid density, l is the characteristic dimension of the object, c is the speed of sound in the fluid, v is the fluid flow rate; w₁Can be simplified as follows:

W₁＝A₁·v⁴ (2)

dipole sound source acoustic power W₂Proportional to the airflow velocity to the power of 6:

can be expressed as:

W₂＝A₂·v⁶ (4)

the sound power W4 of the quadrupole sound source is proportional to the 8 th power of the airflow velocity:

can be expressed as:

W₄＝A₄·v⁸ (6)

sound power level of monopole, dipole and quadrupole sound sourcesNamely:

in the formula W_refFor reference acoustic power, value is 10^-12w。

In practical cases, the sound source is composed of three sound sources, namely, a monopole sound source, a dipole sound source and a quadrupole sound source, so that the total sound power level can be expressed as follows through formula (7), formula (8) and formula (9):

L_W＝x·log(v)+y (10)

wherein x and y are constants, and the value of x is generally between 40 and 80 for different air conditioning box structures. For a given model of vehicle, the transfer function of the sound power level of the pipeline sound source to the sound pressure level at the passenger ear in the vehicle is a fixed constant:

L_P＝L_W+constant＝x·log(v)+y+constant (11)

in the formula L_PConstant is a constant value of the sound pressure level of the human ear

The wind speed in the air blowing pipeline of the air conditioner is different at each position along with the trend and the position change of the pipeline, and the accurate wind speed cannot be obtained for calculation. However, the wind speed of each position is in direct proportion to the total air volume of the air conditioner, and the total air volume is easily and accurately obtained:

in the formula, Q is air volume, S is the sectional area of the pipeline, rho is fluid density, and v represents fluid flow rate; then, combining equation (11) and equation (12), we can obtain:

L_P＝x·log(Q)-x·log(ρS)+y+constant

when-x.log (ρ S) + y + constant in the formula is defined as z, it can be obtained:

L_P＝x·log(Q)+z (13)

therefore, the noise sound pressure level at the ear part and the logarithm of the total air volume of the air conditioning box form a linear relation, and the noise value at the ear part under any air volume can be calculated only by obtaining the values of x and z.

For different air quantities Q_iThe corresponding sound pressure level at the ear is L_iBy measuring the sound pressure levels of n different air volumes, the values of x and z can be obtained by fitting:

taking a certain automobile model as an example, the air conditioner is provided with 8 air volume gears V1-V8, the total air volume Q of air inlet air of the air conditioner at each gear of each mode is measured on an air volume rack, then steady state noise values at the positions of ears of people corresponding to the modes and the gears are measured, and Fourier transform is carried out to obtain a frequency domain 1/n octave frequency spectrum result. The noise measurement can be carried out under the condition of flameout or idling engine starting, and certain fixed voltage can be input into the air blower to obtain the working conditions of different air volumes, so that a plurality of gears of a real vehicle are replaced. The 1/3 octave measurements for the total cold blow out-circulation mode are shown in Table 1. The working condition indicates a working state, for example, blowing or defrosting is different working conditions, heating or cooling is different working conditions, and one-gear wind or eight-gear wind is also different working conditions.

Then, the sound pressure level of each gear noise is compared with the sound pressure level of the background noise when the air conditioner is closed, the total air volume value of the air conditioner with the difference value of the sound pressure of the ventilation noise and the background noise larger than a set value and the sound pressure level of the background noise under the corresponding air volume are selected under each frequency to calculate so as to calculate the corresponding noiseAndin this example, the set value is set to 3dB (A), but is not limited to this value; in this embodiment, noise at idle speed is selected as background noise, the measured value of the background noise is 38db (a), and as shown in table 1, the ventilation noise of the air volume of 1 and 2 is 39.3 and 40.7, respectively, and the difference between the sound pressure level of the ventilation noise and the background noise is less than the set value of 3db (a), so that the values of the air volume of 1 and 2 do not participate in the fitting calculation.Andthe wind volume and noise values are calculated by the formulas 14 and 15 and by using the total 6 gears from V3 to V8. Then pass throughAndcan calculate any air quantity Q_iThe noise sound pressure level at each frequency, as shown in equation 16,the air quantity is Q_iTime frequency f_jLower noise sound pressure level. The background noise refers to noise when the air conditioner is not turned on, such as engine noise and ambient noise. If the background noise is too high, the results of the ventilation noise measurement will be affected and not accurate enough.

The air quantity Q can be obtained through the sound pressure under each frequency_iTotal sound pressure level at_i：

The calculation process is shown in the following table.

TABLE 1 measurement of 1/3 octaves for the total cold blow out of circulation mode

As shown in fig. 2, the solid line is the measurement result and the dotted line is the calculation result of the ventilation noise of 7 windshields of a certain vehicle type calculated by the method of the present invention.

The invention is suitable for various vehicles, such as fuel vehicles, power battery vehicles or hybrid vehicles, and is also suitable for airplanes or other machines capable of measuring the total air volume of the air conditioner, such as engineering machines or household air conditioners.