A method and device for predicting and decomposing external radiated noise

Abstract

The present invention provides a method and device for predicting and decomposing external radiated noise, relating to the technical field of engineering vehicles. The method comprises: setting an external radiated noise target; classifying the external radiated noise sources; obtaining the numerical value or spectral curve of the sound source; obtaining the transfer function of the sound source; predicting the external radiated noise based on the numerical value and transfer function, or the spectral curve and transfer function, to obtain a prediction result; and determining whether the prediction result meets the set external radiated noise target. If so, the prediction result is output; if not, the sound source and transfer function index decomposition is performed. The present invention can predict the external radiated noise and the contribution of each sound source, and decompose the external radiated noise target into various system components.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering vehicles, and in particular to a method and device for predicting and decomposing external radiated noise of a vehicle. Background Art

[0002] The "Law of the People's Republic of China on the Prevention and Control of Noise Pollution," the "Construction Law of the People's Republic of China," the "Environmental Protection Law of the People's Republic of China," and the "Management Specifications for Labor Protective Equipment of Employers" clearly stipulate noise limit standards as effective measures. To implement these regulations, the Ministry of Industry and Information Technology, the Ministry of Ecology and Environment, the Ministry of Housing and Urban-Rural Development, and the State Administration for Market Regulation have finalized the "Guidance List of Low-Noise Construction Equipment (First Batch)" to promote the use of low-noise construction equipment and assist in noise pollution prevention. In November 2023, the European Parliament and the Council issued a document amending the Noise Directive 2000 / 14 / EC. The National Technical Committee for Standardization of Earthmoving Machinery established a standards revision group, and the new version of GB16710 is about to be released. Standards and regulations are increasingly stringent regarding noise levels. Diverse market demands have led to differentiated product configurations and diversified models, with customized designs becoming increasingly prominent. There is an urgent need to predict and decompose external radiated noise during the product design phase.

[0003] The main noise sources for construction vehicles include engine noise, transmission noise, hydraulic system noise, and cooling fan noise. Currently, noise performance development work, which should have been carried out during the product design and trial production phases, is being relegated to the noise improvement phase of mass-produced products. This significantly increases the iterative improvement cycle for noise issues and makes it difficult to meet market demands for rapid response and customization. Currently, during the product design phase, the relationship between component noise and external radiated noise cannot be determined, making it impossible to effectively formulate component noise control requirements, making it difficult to predict and control external radiated noise. To meet the varying noise performance requirements of construction machinery products in different markets, predicting and decomposing external radiated noise for construction vehicles has become a critical issue.

[0004] The general process of the current engineering vehicle noise design method is: prototype offline - external radiated noise test and noise source identification - noise reduction design and improvement of major noise sources - external radiated noise test after improvement to see if it meets the requirements. If the improved prototype noise test meets the requirements, the rectification is completed. If the improved prototype noise test does not meet the requirements, the above process is repeated until the external radiated noise meets the requirements.

[0005] Acoustic simulation software can be used to simulate and design the noise of components such as mufflers and fans. However, when performing vehicle-level noise simulation, due to the large number of sound sources and the different frequency characteristics of different sound sources, it is necessary to comprehensively adopt simulation methods such as finite element method and statistical energy method. Modeling and calculation take a long time, which is difficult to adapt to the product development cycle. In addition, the simulation requires obtaining many parameters, some of which are difficult to obtain. Therefore, vehicle-level noise simulation has not been widely used in the engineering vehicle industry.

[0006] CN202310518674.X proposes a test method for the external noise of a loader. It only needs to set up the test points once at the high-altitude test point, and the vehicle only needs to turn around when the test on one side is completed.

[0007] CN201711105388.1 proposes a low-noise forward design method, which performs vehicle noise simulation analysis based on the optimal parameters of each component.

[0008] CN201811086231.3 discloses a method and system for quickly predicting the exterior noise of a high-speed train. The method simplifies the sound sources in different areas into compact point sound sources, calculates the radiation sound pressure level of each compact point sound source, and establishes an energy superposition model of the radiation sound pressure levels of multiple compact point sound sources.

[0009] CN201610669592.5 discloses an ultra-low noise explosion-proof hydraulic excavator. The explosion-proof air-conditioning system is driven by an auxiliary hydraulic motor and can achieve the functions of refrigeration and temperature regulation.

[0010] CN202011560561.9 discloses a method for predicting and reducing exterior vehicle noise, detailing how to model and conduct simulation analysis.

[0011] CN202311473240.9 discloses a method for predicting exterior vehicle noise based on machine learning, which predicts exterior vehicle noise through the noise of each sound source.

[0012] CN202311538489.3 discloses a key system target confirmation method for passing noise based on a neural network, which predicts passing noise through key vehicle structural parameters and vehicle key subsystem noise data. Summary of the Invention

[0013] To address the technical issues that the existing technology cannot determine the relationship between the noise of each component and the external radiation noise, lacks a method for calculating and predicting the external radiation noise, cannot obtain the noise distribution, cannot effectively know the contribution of each noise source, cannot propose component noise control requirements, cannot control the external radiation noise from the design stage, and often requires several rounds of rectification after the prototype is offline to meet the noise requirements, which not only prolongs the product development cycle, but also wastes human and material resources and increases product development costs, the embodiment of the present invention provides a method and device for predicting and decomposing the external radiation noise. The technical solution is as follows:

[0014] In one aspect, a method for predicting and decomposing external radiated noise is provided. The method is implemented by an external radiated noise prediction and decomposition device, and the method includes:

[0015] S1. Set the external radiated noise target.

[0016] S2. Classify the sources of external radiated noise.

[0017] S3. Obtain the numerical value or spectrum curve of the sound source.

[0018] S4. Obtain the transfer function of the sound source.

[0019] S5. Predict the external radiated noise based on the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result.

[0020] S6. Determine whether the prediction result meets the set external radiated noise target. If so, output the prediction result. If not, perform sound source and transfer function index decomposition.

[0021] Optionally, the sound sources in S2 include: engine noise, cooling system noise, exhaust noise, intake noise, hydraulic component noise, and transmission component noise.

[0022] Optionally, the transfer function in S4 includes: an exhaust transfer function, an intake transfer function, a cooling system transfer function, an engine transfer function, a transmission component transfer function, and a hydraulic component transfer function.

[0023] Among them, the exhaust transfer function is the exhaust correction value S in the entire frequency band e Or the exhaust transfer function TF in the 1 / 3 octave band of the center frequency f ef .

[0024] Among them, the exhaust correction amount S in the entire frequency band e As shown in the following equation (1), the exhaust gas transfer function TF in the 1 / 3 octave band of the center frequency f is ef As shown in the following formula (2):

[0025]

[0026]

[0027] Where r represents the radius of the hemispherical surface for the test of the external radiated sound power level, x1, x2, x3, x4, x5, and x6 represent the distances from the exhaust port to the six measuring points specified in the standard, and TF ief Represents the sound pressure level of the noise value at the i-th measuring point.

[0028] The intake transfer function is the intake correction value S in the entire frequency band a Or the intake air transfer function TF in the 1 / 3 octave band of the center frequency f af .

[0029] Among them, the intake correction amount S in the entire frequency band a As shown in the following equation (3), the transfer function TF of the intake air in the 1 / 3 octave band of the center frequency f is af As shown in the following formula (4):

[0030]

[0031]

[0032] Where y1, y2, y3, y4, y5, and y6 represent the distances between the six measuring points specified in the air inlet distance standard, and TF iaf Represents the sound pressure level of the noise value at the i-th measuring point.

[0033] The cooling system transfer function is the sound insulation N of the hood to the cooling system in the entire frequency band. f Or the transfer function TF of the cooling system in the 1 / 3 octave band of the center frequency f ff .

[0034] Among them, the sound insulation value of the hood to the cooling system in the entire frequency band is N f As shown in the following equation (5), the transfer function TF of the cooling system in the 1 / 3 octave band of the center frequency f is ff As shown in the following formula (6):

[0035]

[0036]

[0037] Where, L f Indicates the sound power level of the cooling system under a certain working condition. L indicates the external radiated sound power level of the whole machine under the corresponding working condition in the fixed state. L0 indicates the sound power level of the whole machine under the corresponding working condition in the fixed state with the fan removed. TF iff Represents the sound pressure level of the noise value at the i-th measuring point.

[0038] The engine transfer function is the sound insulation N of the hood to the engine in the entire frequency band. m Or the engine transfer function TF in the 1 / 3 octave band of the center frequency f mf .

[0039] Among them, the sound insulation of the hood to the engine in the entire frequency band is N m As shown in the following equation (7), the engine transfer function TF in the 1 / 3 octave band of the center frequency f is mf As shown in the following formula (8):

[0040]

[0041]

[0042] Where, L m Indicates the sound power level of the engine under a certain working condition, P e Indicates the sound pressure level at 0.5 meters at the exhaust port under the corresponding working conditions, P a Indicates that the sound pressure level at 0.5 meters under the corresponding working conditions of the air outlet is TF ijmf It represents the sound pressure level of the noise value at the i-th measuring point on the j-th surface.

[0043] The transmission component transfer function is the sound insulation N of the hood to the transmission component in the entire frequency band. c Or the transfer function TF of the transmission component in the 1 / 3 octave band of the center frequency f cf .

[0044] Among them, the sound insulation of the hood to the transmission parts in the entire frequency band is N c As shown in the following formula (9), the transfer function TF of the transmission component in the 1 / 3 octave band of the center frequency f is cf As shown in the following formula (10):

[0045]

[0046]

[0047] Where, L c Indicates the sound power level of the transmission component under a certain working condition. L1 indicates the external radiated sound power level of the whole machine under the corresponding working condition in the stationary state. L2 indicates the sound power level of the whole machine under the corresponding working condition in the stationary state. TF ijcf It represents the sound pressure level of the noise value at the i-th measuring point on the j-th surface.

[0048] The transfer function of the hydraulic components is the sound insulation N of the hood to the hydraulic components in the entire frequency band. y Or the transfer function TF of the hydraulic component in the 1 / 3 octave band of the center frequency f yf .

[0049] Among them, the sound insulation of the hood to the hydraulic components in the entire frequency band is N y As shown in the following equation (11), the transfer function TF of the hydraulic component in the 1 / 3 octave band of the center frequency f is yf As shown in the following formula (12):

[0050]

[0051]

[0052] Where, L y Indicates the sound power level of the hydraulic components under a certain working condition, L3 indicates the sound power level of the whole machine under the corresponding working condition in the fixed state, TF ijyf It represents the sound pressure level of the noise value at the i-th measuring point on the j-th surface.

[0053] Optionally, in S5, performing external radiated noise prediction based on the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result includes:

[0054] S51. Calculate the external radiated noise and the energy ratio of each sound source to the external radiated noise in the entire frequency band based on the numerical value and the transfer function.

[0055] S52. Calculate, based on the frequency spectrum curve and the transfer function, the sound power level of the external radiated noise within a 1 / 3 octave band with a center frequency of f, and the energy contribution ratio of each sound source to the external radiated noise within the 1 / 3 octave band with a center frequency of f.

[0056] Optionally, the external radiation noise in S51 is expressed as follows (13):

[0057]

[0058] Where, L W Indicates the sound power level of the external radiated noise in the entire frequency band, SWL m Indicates the sound power level of the engine in the entire frequency band, N m Indicates the sound insulation of the hood to the engine in the entire frequency band, SWL f Indicates the sound power level of the cooling system in the entire frequency band, N f Indicates the sound insulation of the hood to the cooling system in the entire frequency band, SWL c Indicates the sound power level of the transmission component in the entire frequency band, N c Indicates the sound insulation of the hood to the transmission parts in the entire frequency band, SWL y Indicates the sound power level of hydraulic components in the entire frequency band, N y Indicates the sound insulation of the hood to the hydraulic components in the entire frequency band, SWL e Indicates the exhaust sound power level in the entire frequency band, S eIndicates the exhaust correction amount in the entire frequency band, SWL a Indicates the sound power level of intake air in the entire frequency band, S a Indicates the intake correction amount in the entire frequency band.

[0059] The energy ratio of each sound source to the external radiated noise in the entire frequency band is shown in the following formula (14):

[0060]

[0061] Where k i Indicates the energy ratio of each sound source to the external radiated noise in the entire frequency band, SWL i Indicates the sound power level of a sound source in the entire frequency band, TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band.

[0062] Optionally, the sound power level of the external radiated noise in S52 within a 1 / 3 octave band with a center frequency of f is as shown in the following equation (15):

[0063]

[0064] Where, L Wf It indicates the sound power level of the external radiated noise in the 1 / 3 octave band with the center frequency f, SWL mf Indicates the sound power level of the engine in the 1 / 3 octave band with the center frequency f, TF mf It represents the transfer function of the generator in the 1 / 3 octave band of the center frequency f, SWL ff It represents the sound power level of the cooling system in the 1 / 3 octave band with the center frequency f, TF ff It represents the transfer function of the cooling system in the 1 / 3 octave band of the center frequency f, SWL cf Indicates the sound power level of the transmission component in the 1 / 3 octave band of the center frequency f, TF cf It represents the transfer function of the transmission component in the 1 / 3 octave band of the center frequency f, SWL yf Indicates the sound power level of hydraulic components in the 1 / 3 octave band with the center frequency f, TF yf It represents the transfer function of the hydraulic component in the 1 / 3 octave band of the center frequency f, SWL ef It represents the sound power level of exhaust in the 1 / 3 octave band with the center frequency f, TF ef It represents the exhaust transfer function in the 1 / 3 octave band of the center frequency f, SWL af Indicates the sound power level of the intake air in the 1 / 3 octave band with the center frequency f, TF af It represents the transfer function of the intake air in the 1 / 3 octave band of the center frequency f, S iIt represents the area of ​​the predicted sphere with radius i, and S0 represents the area of ​​the reference surface.

[0065] The energy ratio of each sound source to the external radiated noise in the 1 / 3 octave band of the center frequency f is shown in the following formula (16):

[0066]

[0067] Where k if Indicates the contribution energy ratio of a sound source in the 1 / 3 octave band with the center frequency f, SWL if Indicates the sound power level of a sound source in a 1 / 3 octave band with a center frequency of f, TF if It represents the transfer function of a sound source in a 1 / 3 octave band with a center frequency of f.

[0068] Optionally, the index decomposition in S6 is as shown in the following equations (17) and (18):

[0069]

[0070]

[0071] Where SWL i Indicates the sound power level of a sound source in the entire frequency band, TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band. Indicates the contribution, L Wb Indicates the external radiation noise index requirements in the entire frequency band, SWL if Indicates the sound power level of a sound source in a 1 / 3 octave band with a center frequency of f, TF if It represents the transfer function of a sound source in the 1 / 3 octave band with the center frequency f, S i represents the predicted area of ​​the sphere with radius i, S0 represents the reference surface area, L Wfb Indicates the index requirements for external radiated noise within the 1 / 3 octave band of the center frequency f.

[0072] On the other hand, a device for predicting and decomposing external radiated noise is provided. The device is applied to the method for predicting and decomposing external radiated noise. The device includes:

[0073] The setting module is used to set the external radiated noise target.

[0074] The division module is used to divide the sound sources of external radiated noise.

[0075] The first acquisition module is used to obtain the value or spectrum curve of the sound source.

[0076] The second acquisition module is used to obtain the transfer function of the sound source.

[0077] The prediction module is used to predict the external radiated noise according to the numerical value and the transfer function, or the spectrum curve and the transfer function, and obtain the prediction result.

[0078] The output module is used to determine whether the prediction results meet the set external radiated noise target. If so, the prediction results are output; if not, the sound source and transfer function index decomposition is performed.

[0079] On the other hand, a device for predicting and decomposing external radiation noise is provided, comprising: a processor; and a memory storing computer-readable instructions. When the computer-readable instructions are executed by the processor, any one of the above-mentioned methods for predicting and decomposing external radiation noise is implemented.

[0080] On the other hand, a computer-readable storage medium is provided, wherein the storage medium stores at least one instruction, and the at least one instruction is loaded and executed by a processor to implement any one of the above-mentioned methods for predicting and decomposing external radiation noise.

[0081] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention include at least:

[0082] In an embodiment of the present invention, during the new product design phase, the indicators of each component can be decomposed based on the external radiation noise indicator, so that the noise control of the components can be achieved during the design phase. The contribution of each sound source can also be accurately obtained during the prototype debugging phase.

[0083] The present invention can avoid relying entirely on the test of physical prototypes during the product development process, avoid the test, rectification and retesting work after the prototype is offline, and save product development costs.

[0084] The present invention does not rely entirely on simulation, but is based on a data calculation method, and can obtain the pass-by noise result more quickly and accurately. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0086] Figure 1 This is a flow chart of a method for predicting external radiated noise and decomposing indicators provided by an embodiment of the present invention;

[0087] Figure 2 This is a diagram of the sound source division without a hood provided by an embodiment of the present invention;

[0088] Figure 3 This is a diagram of an earthmoving machine with a hood provided by an embodiment of the present invention;

[0089] Figure 4 This is a measuring point diagram of earthmoving machinery provided by an embodiment of the present invention;

[0090] Figure 5 This is a diagram of the arrangement of intake and exhaust measurement points provided by an embodiment of the present invention;

[0091] Figure 6 This is a block diagram of an off-board radiated noise prediction and index decomposition device provided by an embodiment of the present invention;

[0092] Figure 7 The present invention provides a schematic structural diagram of an off-board radiated noise prediction and index decomposition device. DETAILED DESCRIPTION

[0093] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0094] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as an "exemplary" in the present invention should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of the word "exemplary" is intended to present concepts in a concrete manner. Furthermore, in the embodiments of the present invention, "and / or" can mean both or either of the two.

[0095] In the embodiments of the present invention, the terms "image" and "picture" may be used interchangeably. It should be noted that, when the distinction between them is not emphasized, their intended meanings are the same. The terms "of," "corresponding," and "corresponding" may be used interchangeably. It should be noted that, when the distinction between them is not emphasized, their intended meanings are the same.

[0096] In the embodiments of the present invention, sometimes a subscript such as W1 may be written as a non-subscript such as W1. When the difference is not emphasized, the meanings to be expressed are the same.

[0097] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0098] The embodiment of the present invention provides a method for predicting and decomposing external radiation noise. The method can be implemented by an external radiation noise prediction and index decomposition device, which can be a terminal or a server. Figure 1The flowchart of the method for predicting and decomposing external radiated noise is shown in FIG. The processing flow of the method may include the following steps:

[0099] S1. Set the external radiated noise target.

[0100] In a feasible implementation, the external radiated sound power level of the new model is determined within the entire frequency band or within a certain 1 / 3 octave band according to relevant standard requirements, customer requirements or design requirements.

[0101] S2. Classify the sources of external radiated noise.

[0102] In a feasible implementation method, the external radiated noise is formed by the superposition of the noise of various components, such as Figure 2 、 Figure 3 As shown, the contribution of each component's noise to the measurement point is calculated, and then the noise contributions of each component are added together to predict the external radiated noise level. The external radiated noise is decomposed into the main noise sources such as engine noise, cooling system noise, exhaust noise, intake noise, hydraulic component noise, and transmission component noise.

[0103] S3. Obtain the numerical value or spectrum curve of the sound source.

[0104] Specifically, 1) engine sound power level SWL m or SWL mf The engine body radiated sound power level value SWL can be obtained from the engine supplier according to GB / T1859 "Engineering method and simplified method for measuring air noise radiated by reciprocating internal combustion engines" m Or spectrum curve SWL mf If the data provided does not match the required speed conditions, based on existing test data statistics, a correction can be made based on the noise increasing by 1dB(A) for every 100rpm increase in engine speed.

[0105] 2) Cooling system sound power level SWL f or SWL ff It can be obtained from the cooling system supplier. Based on the design speed ratio of the engine and cooling system, refer to the measurement point arrangement of GB / T 25612 "Earth-moving machinery - Determination of sound power levels - Stationary test conditions", and test the cooling system noise sound power level value SWL at the corresponding speed. f Or spectrum curve SWL ff The cooling system requires a test of the radiated sound power level of the fan and radiator. If the radiator cannot be provided, a correction must be added to the noise data of the cooling fan alone. For curved fan blades, a 6dB(A) increase is recommended after matching the radiator. For linear fan blades, a 3dB(A) increase is recommended after matching the radiator.

[0106] 3) Exhaust sound power level SWL e or SWL ef Exhaust Sound Power Level SWL e or SWL ef The noise sound pressure level SPL at 0.5 meters from the exhaust port e or SPL ef The noise value at 0.5 meters from the exhaust port can be obtained from the exhaust supplier, or from the data accumulated in the previous vehicle test, such as Figure 4 As shown. Simplify the exhaust noise into a point sound source centered at the center of the exhaust port. If the directionality of the exhaust noise is not considered, then according to the point sound source spherical radiation calculation method, the exhaust sound power level SWL e or SWL ef And the noise sound pressure level SPL at 0.5 meters from the exhaust port e or SPL ef The relationship within the entire frequency band or a certain 1 / 3 octave band is as follows:

[0107] SWL e =SPL e +10*lg(4π*0.5 2 )=SPL e +5 (1)

[0108] SWL ef =SPL ef +10*lg(4π*0.5 2 )=SPL ef +5 (2)

[0109] However, the directionality of exhaust noise is quite obvious. The sound pressure value at the same distance between the front and back of the exhaust port differs by about 4dB(A). After taking the directionality of exhaust noise into consideration through actual vehicle directionality test and point sound source simulation test, the exhaust sound power level SWL e or SWL ef And the noise sound pressure level SPL at 0.5 meters from the exhaust port e or SPL ef The relationship over the entire frequency band or within a 1 / 3 octave band can be defined as:

[0110] SWL e =SPL e +2 (3)

[0111] SWL ef =SPL ef +2 (4)

[0112] 4) Intake sound power level SWL a or SWL af Intake Sound Power Level SWLa or SWL af The noise sound pressure level SPL at 0.5 meters from the air inlet a or SPL af The noise value at 0.5 meters from the air inlet can be obtained from the air inlet supplier, or from the data accumulated in the previous vehicle test, such as Figure 4 The intake noise is simplified to a point sound source centered at the center of the air inlet. According to the sound source spherical radiation calculation method, the intake sound power level SWL a or SWL af And the noise sound pressure level SPL at 0.5 meters from the air inlet a or SPL af The relationship within the entire frequency band or a certain 1 / 3 octave band is as follows:

[0113] SWL a =SPL a +10*lg(4π*0.5 2 )=SPL a +5 (5)

[0114] SWL af =SPL af +10*lg(4π*0.5 2 )=SPL af +5 (6)

[0115] 5) Transmission component sound power level SWL c or SWL cf It can be obtained from the transmission component supplier. Based on the design speed ratio of the engine and transmission components, refer to the measurement point arrangement of GB / T 25612 "Earth-moving machinery - Determination of sound power levels - Stationary test conditions", and test the transmission component noise sound power level value SWL at the corresponding speed. c Or spectrum curve SWL cf .

[0116] 6) Hydraulic components sound power level SWL y or SWL yf It can be obtained from the hydraulic component supplier. Based on the design speed ratio of the engine and transmission components, refer to the measurement point arrangement of GB / T 25612 "Earth-moving machinery - Determination of sound power levels - Stationary test conditions", and test the sound power level value SWL of the hydraulic component noise at the corresponding speed. y Or spectrum curve SWL yf .

[0117] S4. Obtain the transfer function of the sound source.

[0118] Optionally, the transfer function in S4 may include: an exhaust transfer function, an intake transfer function, a cooling system transfer function, an engine transfer function, a transmission component transfer function, and a hydraulic component transfer function, etc.

[0119] 1) Exhaust transfer function S e or TF ef :S e Here, the exhaust correction amount is used to express it. Assume that the radius of the hemispherical surface for the test of the external radiated sound power level is r, and the distances from the exhaust port to the six measuring points specified in the standard are x1, x2, x3, x4, x5, and x6, respectively. Figure 5 As shown, according to the noise radiation law of point sound source, the noise correction amount S caused by the exhaust port deviating from the center of the whole machine is e It can be calculated by the following formula:

[0120]

[0121] TF ef The sound pressure level of the noise in each 1 / 3 octave band at six measurement points outside the vehicle is measured using a microphone. ef It can be calculated by the following formula:

[0122]

[0123] Where: TF ief It represents the noise value sound pressure level at the i-th measuring point, in decibels (dB).

[0124] 2) Intake transfer function S a or TF af :S a Here, the air intake correction is used to express it. Assume that the radius of the hemispherical surface for the external radiated sound power level test is r, and the distances between the air intake and the six measuring points specified in the standard are y1, y2, y3, y4, y5, and y6, respectively. Based on the noise radiation law of point sound sources, the noise correction S4 caused by the air intake deviating from the center of the whole machine can be calculated by the following formula:

[0125]

[0126] TF af The sound pressure level of the noise in each 1 / 3 octave band at six measurement points outside the vehicle is measured using a microphone. af It can be calculated by the following formula:

[0127]

[0128] Where: TFiaf It represents the noise value sound pressure level at the i-th measuring point, in decibels (dB).

[0129] 3) Cooling system transfer function N f or TF ff :N f Here, the sound insulation of the cooling system is expressed by the hood, which can be obtained through physical testing of similar models of the previous generation. The test method is as follows: The sound power level of the cooling system under a certain working condition is known to be L f The sound power level of the external radiation of the whole machine under the working condition of the fixed state is L, and the sound power level of the whole machine under the working condition of the fixed state with the fan removed is L0. The contribution of the fan to the sound power level of the whole machine is 10*lg(10 0.1*L -10 0.1*L0 ). Then the noise insulation of the hood to the cooling system noise is N f for:

[0130]

[0131] TF ff The sound pressure level of the noise in each 1 / 3 octave band at six measurement points outside the machine is measured using a microphone. ff It can be calculated by the following formula:

[0132]

[0133] Where: TF iff It represents the noise value sound pressure level at the i-th measuring point, in decibels (dB).

[0134] 4) Engine transfer function N m or TF mf :N m Here, the engine hood is used to represent the sound insulation of the engine, which can be obtained through physical testing of similar models of the previous generation. The test method is as follows: It is known that the sound power level of the engine under a certain working condition is L m The sound power level of the external radiation of the whole machine under the working condition of the fixed state (not starting the transmission components and hydraulic components) is L, the sound power level of the whole machine under the working condition of the fan removal state (not starting the transmission components and hydraulic components) is L0, and the sound pressure level at 0.5 meters under the working condition of the exhaust port is P e , the sound pressure level at 0.5 meters under the corresponding working conditions of the air inlet is P a Without starting the transmission and hydraulic components, the engine's contribution to the overall sound power level is 10*lg(10 0.1*L0 -10 0.1*(Pe+2+Se) -10 0.1*(Pa+5+Sa) ), then the sound insulation of the hood to the engine noise is N m for:

[0135]

[0136] TF mf The sound pressure level of the six external sound power points in each 1 / 3 octave band is measured using a microphone. ff It can be calculated by the following formula:

[0137]

[0138] Where: TF ijmf It represents the noise sound pressure level at the i-th measuring point on the j-th surface, in decibels (dB).

[0139] 5) Transmission component transfer function N c or TF cf :N c Here, the sound insulation of the transmission components is expressed by the engine cover, which can be obtained through physical testing of similar models of the previous generation. The test method is as follows: The sound power level of the transmission component under a certain working condition is known to be L c , the sound power level of the external radiation of the whole machine under the working condition of the fixed state is L1, and the sound power level of the whole machine under the working condition of the fixed state (without turning on the transmission components) is L2, so the contribution of the transmission components to the sound power level of the whole machine is 10*lg(10 0.1*L1 -10 0.1*L2 ). Then the sound insulation of the hood to the noise of the transmission parts is N c for:

[0140]

[0141] TF cf The sound pressure level of the noise in each 1 / 3 octave band at the six measurement points of the external sound power is measured using a microphone. cf It can be calculated by the following formula:

[0142]

[0143] Where: TF ijcf It represents the noise sound pressure level at the i-th measuring point on the j-th surface, in decibels (dB).

[0144] 6) Hydraulic component transfer function N y or TF yf :N yHere, the sound insulation of the hydraulic components by the hood is expressed, which can be obtained through physical testing of similar models of the previous generation. The test method is as follows: It is known that the sound power level of the hydraulic component under a certain working condition is L y , the sound power level of the external radiation of the whole machine under the working condition of the fixed state is L1, and the sound power level of the whole machine under the working condition of the fixed state (without opening the hydraulic components) is L3, so the contribution of the hydraulic components to the sound power level of the whole machine is 10*lg(10 0.1*L1 -10 0.1*L3 ). Then the sound insulation of the hood to the noise of hydraulic components is N y for:

[0145]

[0146] TF yf The sound pressure level of the six external sound power points in each 1 / 3 octave band is measured using a microphone. yf It can be calculated by the following formula:

[0147]

[0148] Where: TF ijyf It represents the noise sound pressure level at the i-th measuring point on the j-th surface, in decibels (dB).

[0149] S5. Predict the external radiated noise based on the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result.

[0150] Optionally, the above step S5 may include the following steps S51-S52:

[0151] S51. Calculate the external radiated noise and the energy ratio of each sound source to the external radiated noise in the entire frequency band based on the numerical value and the transfer function.

[0152] In a feasible implementation, when only a single value of each sound source characteristic and transfer function over the entire frequency band is available, a synthetic calculation method based on an empirical formula is proposed.

[0153] External radiated sound power level L W It can be calculated by the following formula:

[0154]

[0155] Where, L W It indicates the sound power level of the external radiated noise in the entire frequency band, in decibels (dB), SWL m Indicates the sound power level of the engine in the entire frequency band, in decibels (dB), Nm Indicates the sound insulation of the hood to the engine in the entire frequency band, in decibels (dB), SWL f It indicates the sound power level of the cooling system in the entire frequency band, in decibels (dB), N f Indicates the sound insulation of the hood to the cooling system in the entire frequency band, in decibels (dB), SWL c It indicates the sound power level of the transmission component in the entire frequency band, in decibels (dB), N c It indicates the sound insulation of the hood to the transmission parts in the entire frequency band, in decibels (dB), SWL y It indicates the sound power level of hydraulic components in the entire frequency band, in decibels (dB), N y Indicates the sound insulation of the hood to the hydraulic components in the entire frequency band, in decibels (dB), SWL e It indicates the sound power level of exhaust in the entire frequency band, in decibels (dB), S e Indicates the amount of exhaust correction in the entire frequency band, in decibels (dB), SWL a Indicates the sound power level of the intake air in the entire frequency band, in decibels (dB), S a Indicates the amount of intake correction in the entire frequency band, in decibels (dB).

[0156] The energy ratio of each sound source to the external radiated noise in the entire frequency band is shown in the following formula (20):

[0157]

[0158] Where k i Indicates the energy ratio of each sound source to the external radiated noise in the entire frequency band, the unit is %, SWL i Indicates the sound power level of a sound source in the entire frequency band, TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band, in decibels (dB).

[0159] S52. Calculate, based on the frequency spectrum curve and the transfer function, the sound power level of the external radiated noise within a 1 / 3 octave band with a center frequency of f, and the energy contribution ratio of each sound source to the external radiated noise within the 1 / 3 octave band with a center frequency of f.

[0160] In a feasible implementation, when the characteristics of each sound source and the transfer function curve values ​​in the 1 / 3 octave band are available, a one-dimensional calculation method based on spectrum data is proposed.

[0161] The contribution of each sound source to the external radiated noise in each 1 / 3 octave band is:

[0162] SPL ii =SWLii +TF ii -120 (21)

[0163] Of which: SPL ii SWL is the sound pressure level of the external radiated noise measurement point in a certain 1 / 3 octave band, in decibels (dB); ii The sound power level of a sound source in a certain 1 / 3 octave band, measured in decibels (dB); TF ii It is the transfer function of a sound source in a certain 1 / 3 octave band when the incident sound power is 1W, and the unit is decibel (dB).

[0164] The noise value of the external radiation noise in each 1 / 3 octave band is calculated according to formula (22):

[0165]

[0166] Where, L Wf It indicates the sound power level of the external radiated noise in the 1 / 3 octave band with the center frequency f, in decibels (dB). mf It indicates the sound power level of the engine in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF mf It represents the transfer function of the engine in the 1 / 3 octave band of the center frequency f, in decibels (dB), SWL ff It indicates the sound power level of the cooling system in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF ff It represents the transfer function of the cooling system in the 1 / 3 octave band of the center frequency f, in decibels (dB), SWL cf It indicates the sound power level of the transmission component in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF cf It indicates the transfer function of the transmission component in the 1 / 3 octave band of the center frequency f, in decibels (dB), SWL yf It indicates the sound power level of hydraulic components in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF yf It represents the transfer function of the hydraulic component in the 1 / 3 octave band of the center frequency f, in decibels (dB), SWL ef It indicates the sound power level of exhaust in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF ef It represents the exhaust gas transfer function in the 1 / 3 octave band with the center frequency f, in decibels (dB), SWL af It indicates the sound power level of the intake air in the 1 / 3 octave band with the center frequency f, in decibels (dB), TF af It represents the transfer function of the intake air in the 1 / 3 octave band of the center frequency f, in decibels (dB), Si Indicates the predicted area of ​​the sphere with radius i, in square meters (m 2 ), S0 represents the reference surface area, which is 1m 2 .

[0167] The energy ratio of each sound source to the external radiated noise in the 1 / 3 octave band of the center frequency f is shown in the following formula (23):

[0168]

[0169] Where k if Indicates the contribution energy ratio of a sound source in the 1 / 3 octave band with the center frequency f, in %, SWL if It indicates the sound power level of a sound source in the 1 / 3 octave band with the center frequency f, in decibels (dB). if It represents the transfer function of a sound source in a 1 / 3 octave band with a center frequency of f, in decibels (dB).

[0170] The external radiated noise is calculated according to formula (24):

[0171]

[0172] Where: L W Indicates the noise value of external radiation noise in the entire frequency band, in decibels (dB), L Wi It indicates the noise value of external radiated noise in the 1 / 3 octave band of the center frequency i, in decibels (dB).

[0173] S6. Determine whether the prediction result meets the set external radiated noise target. If so, output the prediction result. If not, perform sound source and transfer function index decomposition.

[0174] In a feasible implementation, if the predicted external radiated noise meets the noise target of step S1, there is no need to perform the following decomposition of the sound sources and transfer functions. If not, the sound sources and transfer function indicators should be reset, the excitation of each sound source should be reduced, the transfer functions should be optimized, and the balance between performance and cost should be sought between each sound source and each transfer function. The external radiated noise is optimized with the external radiated noise as the optimization target, the immutable sound sources and transfer functions as the constraints, and the variable sound sources and transfer functions as the variables. The indicator decomposition can be performed according to the following formula so that the contribution of a certain sound source does not exceed the external radiated noise indicator. times.

[0175]

[0176]

[0177] Where SWL i Indicates the sound power level of a sound source in the entire frequency band, in decibels (dB), TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band, in decibels (dB). Indicates contribution in percentage (%), L Wb Indicates the external radiated noise index requirement in the entire frequency band, in decibels (dB), SWL if It indicates the sound power level of a sound source in the 1 / 3 octave band with the center frequency f, in decibels (dB). if It represents the transfer function of a sound source in the 1 / 3 octave band with the center frequency f, in decibels (dB). Wfb It indicates the external radiated noise requirement within the 1 / 3 octave band of the center frequency f, in decibels (dB).

[0178] Furthermore, the sound power level of each sound source can be assessed based on national standards, industry standards, enterprise standards, benchmark products, or contribution. Sound sources that meet the target requirements are selected from the database. If none exist, the closest sound sources are selected, the transfer function index is adjusted accordingly, and the system returns to the prediction stage to ensure that the calculated external radiated sound power level meets S1.

[0179] Furthermore, the transfer function indicators of each sound source are evaluated: the transfer function of each sound source is judged. If it is less than the preset target, the sound absorption and insulation design of the hood needs to be redesigned, or the intake and exhaust positions need to be adjusted, and the process returns to the prediction part to ensure that the calculated external radiated sound power level meets step S1.

[0180] In an embodiment of the present invention, during the new product design phase, the indicators of each component can be decomposed based on the external radiation noise indicator, so that the noise control of the components can be achieved during the design phase. The contribution of each sound source can also be accurately obtained during the prototype debugging phase.

[0181] The present invention can avoid relying entirely on the test of physical prototypes during the product development process, avoid the test, rectification and retesting work after the prototype is offline, and save product development costs.

[0182] The present invention does not rely entirely on simulation, but is based on a data calculation method, and can obtain the pass-by noise result more quickly and accurately.

[0183] Figure 6 This is a block diagram of an apparatus for predicting and decomposing external radiation noise according to an exemplary embodiment. The apparatus is used in a method for predicting and decomposing external radiation noise. Figure 6The device includes a setting module 310, a division module 320, a first acquisition module 330, a second acquisition module 340, a prediction module 350 and an output module 360.

[0184] The setting module 310 is used to set the external radiated noise target.

[0185] The classification module 320 is used to classify the sound sources of the external radiated noise.

[0186] The first acquisition module 330 is used to obtain the value or frequency spectrum curve of the sound source.

[0187] The second acquisition module 340 is used to acquire the transfer function of the sound source.

[0188] The prediction module 350 is used to predict the external radiated noise according to the numerical value and the transfer function, or the spectrum curve and the transfer function, and obtain a prediction result.

[0189] The output module 360 ​​is used to determine whether the prediction result meets the set external radiated noise target. If so, the prediction result is output; if not, the sound source and transfer function index decomposition is performed.

[0190] In an embodiment of the present invention, during the new product design phase, the indicators of each component can be decomposed based on the external radiation noise indicator, so that the noise control of the components can be achieved during the design phase. The contribution of each sound source can also be accurately obtained during the prototype debugging phase.

[0191] The present invention can avoid relying entirely on the test of physical prototypes during the product development process, avoid the test, rectification and retesting work after the prototype is offline, and save product development costs.

[0192] The present invention does not rely entirely on simulation, but is based on a data calculation method, and can obtain the pass-by noise result more quickly and accurately.

[0193] Figure 7 : is a schematic diagram of the structure of an off-board radiation noise prediction and index decomposition device provided by an embodiment of the present invention, such as Figure 7 As shown, the external radiation noise prediction and index decomposition equipment may include the above Figure 6 Optionally, the device 410 for predicting and decomposing external radiated noise may include a first processor 2001 .

[0194] Optionally, the external radiation noise prediction and index decomposition device 410 may further include a memory 2002 and a transceiver 2003 .

[0195] The first processor 2001, the memory 2002 and the transceiver 2003 may be connected via a communication bus.

[0196] The following combination Figure 7 The components of the external radiated noise prediction and index decomposition device 410 are described in detail:

[0197] The first processor 2001 is the control center of the external radiated noise prediction and index decomposition device 410 and can be a single processor or a collective term for multiple processing elements. For example, the first processor 2001 can be one or more central processing units (CPUs), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement an embodiment of the present invention, such as one or more digital signal processors (DSPs) or one or more field programmable gate arrays (FPGAs).

[0198] Optionally, the first processor 2001 may execute various functions of the off-board radiation noise prediction and index decomposition device 410 by running or executing a software program stored in the memory 2002 and calling data stored in the memory 2002 .

[0199] In a specific implementation, as an embodiment, the first processor 2001 may include one or more CPUs, such as Figure 7 CPU0 and CPU1 are shown in FIG.

[0200] In a specific implementation, as an embodiment, the external radiation noise prediction and index decomposition device 410 may also include multiple processors, such as Figure 7 1 and 2. The first processor 2001 and the second processor 2004 are shown in FIG. Each of these processors can be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein can refer to one or more devices, circuits, and / or processing cores for processing data (e.g., computer program instructions).

[0201] The memory 2002 is used to store the software program for executing the solution of the present invention, and is controlled by the first processor 2001 for execution. The specific implementation method can refer to the above method embodiment and will not be repeated here.

[0202] Alternatively, the memory 2002 may be a read-only memory (ROM) or other type of static storage device capable of storing static information and instructions, a random access memory (RAM) or other type of dynamic storage device capable of storing information and instructions, or an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM) or other optical disc storage, an optical disc storage (including a compact disc, laser disc, optical disc, digital versatile disc, Blu-ray disc, etc.), a magnetic disk storage medium or other magnetic storage device, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and capable of being accessed by a computer, but not limited thereto. The memory 2002 may be integrated with the first processor 2001 or may exist independently and access the memory 2002 through the interface circuit ( Figure 7 (not shown) is coupled to the first processor 2001, which is not specifically limited in this embodiment of the present invention.

[0203] The transceiver 2003 is used to communicate with a network device or a terminal device.

[0204] Optionally, the transceiver 2003 may include a receiver and a transmitter ( Figure 7 (not shown separately in the figure). The receiver is used to implement a receiving function, and the transmitter is used to implement a sending function.

[0205] Optionally, the transceiver 2003 may be integrated with the first processor 2001 or may exist independently and be connected to the first processor 2001 through the interface circuit ( Figure 7 (not shown) is coupled to the first processor 2001, which is not specifically limited in this embodiment of the present invention.

[0206] It should be noted that Figure 7 The structure of the external radiation noise prediction and index decomposition device 410 shown in the figure does not constitute a limitation on the router. The actual knowledge structure recognition device may include more or fewer components than shown in the figure, or combine certain components, or arrange the components differently.

[0207] In addition, the technical effects of the external radiation noise prediction and index decomposition device 410 can refer to the technical effects of the external radiation noise prediction and index decomposition method described in the above method embodiment, and will not be repeated here.

[0208] It should be understood that the first processor 2001 in the embodiment of the present invention may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc.

[0209] It should also be understood that the memory in the embodiments of the present invention may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of random access memory (RAM) are available, such as static RAM (SRAM), dynamic random access memory (DRAM), synchronous DRAM (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link DRAM (SLDRAM), and direct rambus RAM (DR RAM).

[0210] The above embodiments can be implemented in whole or in part through software, hardware (such as circuits), firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the processes or functions described in accordance with the embodiments of the present invention are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired method (such as infrared, wireless, microwave, etc.). The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or data center that contains a collection of one or more available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, or magnetic tape), an optical medium (such as a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0211] It should be understood that the term "and / or" as used herein simply describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. A and B can be singular or plural. Furthermore, the character " / " as used herein generally indicates an "or" relationship between the associated objects, but it may also indicate an "and / or" relationship. For specific understanding, please refer to the context.

[0212] In this disclosure, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c" can mean: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or plural.

[0213] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0214] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0215] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described equipment, devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0216] In the several embodiments provided by the present invention, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interface, indirect coupling or communication connection of the device or unit, which can be electrical, mechanical or other forms.

[0217] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0218] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0219] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0220] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for predicting and decomposing external radiated noise, characterized in that: The method comprises: S1. Set the external radiated noise target; S2. Classify the sources of external radiated noise; S3, obtaining the numerical value or spectrum curve of the sound source; S4, obtaining a transfer function of the sound source; S5. Predicting external radiated noise based on the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result; S6. Determine whether the prediction result meets the set external radiated noise target. If so, output the prediction result; if not, perform sound source and transfer function index decomposition; The sound sources in S2 include: engine noise, cooling system noise, exhaust noise, intake noise, hydraulic component noise and transmission component noise; The transfer functions in S4 include: exhaust transfer function, intake transfer function, cooling system transfer function, engine transfer function, transmission component transfer function and hydraulic component transfer function; The step S5 of predicting the external radiated noise according to the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result includes: S51. Calculate, based on the numerical value and the transfer function, the external radiated noise and the energy ratio of each sound source to the external radiated noise in the entire frequency band; S52. Calculate, based on the frequency spectrum curve and the transfer function, the sound power level of the external radiated noise in a 1 / 3 octave band with a center frequency f and the energy contribution ratio of each sound source to the external radiated noise in the 1 / 3 octave band with a center frequency f; The index decomposition in S6 is shown in the following equations (17) and (18): Where SWL i Indicates the sound power level of a sound source in the entire frequency band, TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band. Indicates the contribution, L Wb Indicates the external radiation noise index requirements in the entire frequency band, SWL if Indicates the sound power level of a sound source in a 1 / 3 octave band with a center frequency of f, TF if It represents the transfer function of a sound source in the 1 / 3 octave band with the center frequency f, S i represents the predicted area of ​​the sphere with radius i, S0 represents the reference surface area, L Wfb Indicates the index requirements for external radiated noise within the 1 / 3 octave band of the center frequency f.

2. The method for predicting and decomposing external radiated noise according to claim 1, wherein: The exhaust transfer function is the exhaust correction value S in the entire frequency band. e Or the exhaust transfer function TF in the 1 / 3 octave band of the center frequency f ef ; Among them, the exhaust correction amount S in the entire frequency band e As shown in the following equation (1), the exhaust gas transfer function TF in the 1 / 3 octave band of the center frequency f is ef As shown in the following formula (2): Where r represents the radius of the hemispherical surface for the test of the external radiated sound power level, x1, x2, x3, x4, x5, and x6 represent the distances from the exhaust port to the six measuring points specified in the standard, and TF ief Indicates the sound pressure level of the noise value at the i-th measuring point; The intake transfer function is the intake correction value S in the entire frequency band. a Or the intake air transfer function TF in the 1 / 3 octave band of the center frequency f af ; Among them, the intake correction amount S in the entire frequency band a As shown in the following equation (3), the transfer function TF of the intake air in the 1 / 3 octave band of the center frequency f is af As shown in the following formula (4): Where y1, y2, y3, y4, y5, and y6 represent the distances between the six measuring points specified in the air inlet distance standard, and TF iaf Indicates the sound pressure level of the noise value at the i-th measuring point; The cooling system transfer function is the sound insulation N of the hood to the cooling system in the entire frequency band. f Or the transfer function TF of the cooling system in the 1 / 3 octave band of the center frequency f ff ; Among them, the sound insulation value of the hood to the cooling system in the entire frequency band is N f As shown in the following equation (5), the transfer function TF of the cooling system in the 1 / 3 octave band of the center frequency f is ff As shown in the following formula (6): Where, L f Indicates the sound power level of the cooling system under a certain working condition. L indicates the external radiated sound power level of the whole machine under the corresponding working condition in the fixed state. L0 indicates the sound power level of the whole machine under the corresponding working condition in the fixed state with the fan removed. TF iff Indicates the sound pressure level of the noise value at the i-th measuring point; The engine transfer function is the sound insulation N of the hood to the engine in the entire frequency band. m Or the engine transfer function TF in the 1 / 3 octave band of the center frequency f mf ; Among them, the sound insulation of the hood to the engine in the entire frequency band is N m As shown in the following equation (7), the engine transfer function TF in the 1 / 3 octave band of the center frequency f is mf As shown in the following formula (8): Where, L m Indicates the sound power level of the engine under a certain working condition, P e Indicates the sound pressure level at 0.5 meters at the exhaust port under the corresponding working conditions, P a Indicates that the sound pressure level at 0.5 meters under the corresponding working conditions of the air outlet is TF ijmf Indicates the noise value sound pressure level at the i-th measuring point on the j-th surface; The transmission component transfer function is the sound insulation value N of the hood to the transmission component in the entire frequency band. c Or the transfer function TF of the transmission component in the 1 / 3 octave band of the center frequency f cf ; Among them, the sound insulation of the hood to the transmission parts in the entire frequency band is N c As shown in the following formula (9), the transfer function TF of the transmission component in the 1 / 3 octave band of the center frequency f is cf As shown in the following formula (10): Where, L c Indicates the sound power level of the transmission component under a certain working condition. L1 indicates the external radiated sound power level of the whole machine under the corresponding working condition in the stationary state. L2 indicates the sound power level of the whole machine under the corresponding working condition in the stationary state. TF ijcf Indicates the noise value sound pressure level at the i-th measuring point on the j-th surface; The hydraulic component transfer function is the sound insulation N of the hood to the hydraulic component in the entire frequency band. y Or the transfer function TF of the hydraulic component in the 1 / 3 octave band of the center frequency f yf ; Among them, the sound insulation of the hood to the hydraulic components in the entire frequency band is N y As shown in the following equation (11), the transfer function TF of the hydraulic component in the 1 / 3 octave band of the center frequency f is yf As shown in the following formula (12): Where, L y Indicates the sound power level of the hydraulic components under a certain working condition, L3 indicates the sound power level of the whole machine under the corresponding working condition in the fixed state, TF ijyf It represents the sound pressure level of the noise value at the i-th measuring point on the j-th surface.

3. The method for predicting and decomposing external radiated noise according to claim 1, wherein: The external radiation noise in S51 is expressed as follows: Where, L W Indicates the sound power level of the external radiated noise in the entire frequency band, SWL m Indicates the sound power level of the engine in the entire frequency band, N m Indicates the sound insulation of the hood to the engine in the entire frequency band, SWL f Indicates the sound power level of the cooling system in the entire frequency band, N f Indicates the sound insulation of the hood to the cooling system in the entire frequency band, SWL c Indicates the sound power level of the transmission component in the entire frequency band, N c Indicates the sound insulation of the hood to the transmission parts in the entire frequency band, SWL y Indicates the sound power level of hydraulic components in the entire frequency band, N y Indicates the sound insulation of the hood to the hydraulic components in the entire frequency band, SWL e Indicates the exhaust sound power level in the entire frequency band, S e Indicates the exhaust correction amount in the entire frequency band, SWL a Indicates the sound power level of intake air in the entire frequency band, S a Indicates the correction amount of intake air in the entire frequency band; The energy ratio of each sound source to the external radiated noise in the entire frequency band is expressed as follows: Where k i Indicates the energy ratio of each sound source to the external radiated noise in the entire frequency band, SWL i Indicates the sound power level of a sound source in the entire frequency band, TF i It indicates the sound insulation of the hood to a certain sound source in the entire frequency band or the correction amount of a certain sound source in the entire frequency band.

4. The method for predicting and decomposing external radiated noise according to claim 1, wherein: The sound power level of the external radiated noise in S52 in the 1 / 3 octave band with the center frequency f is as shown in the following formula (15): Where, L Wf It indicates the sound power level of the external radiated noise in the 1 / 3 octave band with the center frequency f, SWL mf Indicates the sound power level of the engine in the 1 / 3 octave band with the center frequency f, TF mf It represents the transfer function of the generator in the 1 / 3 octave band of the center frequency f, SWL ff It represents the sound power level of the cooling system in the 1 / 3 octave band with the center frequency f, TF ff It represents the transfer function of the cooling system in the 1 / 3 octave band of the center frequency f, SWL cf Indicates the sound power level of the transmission component in the 1 / 3 octave band of the center frequency f, TF cf It represents the transfer function of the transmission component in the 1 / 3 octave band of the center frequency f, SWL yf Indicates the sound power level of hydraulic components in the 1 / 3 octave band with the center frequency f, TF yf It represents the transfer function of the hydraulic component in the 1 / 3 octave band of the center frequency f, SWL ef It represents the sound power level of exhaust in the 1 / 3 octave band with the center frequency f, TF ef It represents the exhaust transfer function in the 1 / 3 octave band of the center frequency f, SWL af Indicates the sound power level of the intake air in the 1 / 3 octave band with the center frequency f, TF af It represents the transfer function of the intake air in the 1 / 3 octave band of the center frequency f, S i represents the area of ​​the predicted sphere of radius i, and S0 represents the area of ​​the reference surface; The energy ratio of each sound source to the external radiated noise in the 1 / 3 octave band with the center frequency f is expressed as follows (16): Where k if Indicates the contribution energy ratio of a sound source in the 1 / 3 octave band with the center frequency f, SWL if Indicates the sound power level of a sound source in a 1 / 3 octave band with a center frequency of f, TF if It represents the transfer function of a sound source in a 1 / 3 octave band with a center frequency of f.

5. A device for predicting and decomposing external radiated noise, the device being used to implement the method for predicting and decomposing external radiated noise according to any one of claims 1 to 4, characterized in that: The device comprises: Setting module, used to set the external radiated noise target; A division module is used to divide the sound sources of external radiated noise; A first acquisition module is used to obtain the value or spectrum curve of the sound source; A second acquisition module is used to obtain the transfer function of the sound source; A prediction module, configured to predict external radiated noise based on the numerical value and the transfer function, or the spectrum curve and the transfer function, to obtain a prediction result; The output module is used to determine whether the prediction result meets the set external radiated noise target. If so, the prediction result is output; if not, the sound source and transfer function index decomposition is performed.

6. An external radiated noise prediction and index decomposition device, characterized in that: The external radiated noise prediction and index decomposition equipment includes: processor; A memory having computer-readable instructions stored thereon, wherein when the computer-readable instructions are executed by the processor, the method according to any one of claims 1 to 4 is implemented.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores program code, which can be called by a processor to execute the method according to any one of claims 1 to 4.

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