Method and device for intake port order noise target ranking based on harmonic signal sounder

Abstract

This invention discloses a method and apparatus for classifying and determining the target of intake order noise based on a harmonic signal generator. The method includes dividing in-vehicle noise into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and acquiring the in-vehicle background noise; calculating the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and classifying the target of intake order noise based on the characteristic loudness of the in-vehicle background noise; simulating intake order noise at the intake through a harmonic signal generator so that the frequency and amplitude of the intake order noise transmitted into the vehicle are the same as the frequency and amplitude of the corresponding target intake order noise at each level; acquiring the simulated intake order noise, and classifying the target of intake order noise based on the simulated intake order noise. This invention achieves the separation of in-vehicle intake order noise from other background noise, the setting of target of in-vehicle intake order noise based on human auditory system perception, and the decomposition of in-vehicle intake order noise into intake order noise based on quantitative active sound generation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle noise control, and particularly relates to an air inlet order noise target grading method and device based on a harmonic signal sound generator. BACKGROUND

[0002] Engine air intake system pipe order noise is an important indicator affecting the comfort of car passengers. The air intake pipe of a passenger car is generally arranged on the upper side of the front grille, and the air inlet order noise is transmitted to the car through the air-front sound insulation material on the upper and lower sides of the engine compartment cover, the car body sheet metal and the windshield glass. If the air inlet order noise is too large, it will resonate with the car body sheet metal or sound cavity to produce a "buzz" sound, resulting in a noisy car interior, affecting passenger communication, and in severe cases, causing the eardrum to be impacted by sound waves, leading to tinnitus, irritability, and even dizziness, affecting the physical and mental health of passengers. Currently, when developing a new vehicle model, the target is usually set by benchmarking the air inlet order noise of a competitor's vehicle on the market.

[0003] The current technology has the following problems. The whole vehicle is a complex, multi-excitation, and multi-transmission path vibration noise system. In addition to the air intake order noise, there are also wind excitation, road excitation, powertrain excitation, and exhaust system excitation causing noise in the car. The structures of different vehicle models are different, and the differences between the noises of each part are as different as heaven and earth. Whether the air intake order noise in the car can be perceived by passengers is related not only to its size, but also to the size of other noises in the car. There is a great risk in considering only the size of the air intake order noise in the car. It needs to be matched according to different vehicle models. The air inlet order noise is transmitted to the car interior after being attenuated by the sound insulation of the car body parts. The size of the air intake order noise perceived by the passengers in the car is related not only to the air inlet order noise, but also to the car body noise transmission function. If only the benchmarking method is used to set the target of the newly developed vehicle model according to the air inlet order noise of the benchmarking vehicle, the influence of other excitation noise and the sound insulation attenuation characteristics of the car body on the perception of passengers will be ignored. In addition, if the air inlet order noise target is too strict, it will lead to high cost and weight of the air intake noise reduction scheme, resulting in waste. If the air inlet order noise target is too loose, it will result in excessive noise in the car, affecting the product competitiveness. Therefore, the development of the air inlet order noise target needs to consider the acoustic performance of the whole vehicle, the cost of the whole vehicle, and the market competitiveness of the whole vehicle. SUMMARY

[0004] The purpose of the present application is to provide an air inlet order noise target grading method and device based on a harmonic signal sound generator, which separates the air intake order noise in the car from other background noise, sets the air intake order noise target in the car based on the human auditory system perception, and decomposes the air intake order noise in the car to the air inlet order noise based on the quantitative active sound generation, so as to solve the problems in the background technology.

[0005] To achieve the above object, the application provides the following technical scheme: a method for establishing target classification of intake port order noise based on harmonic signal sound generator, comprising:

[0006] Divide the interior noise into interior intake order noise and interior background noise caused by other factors, and obtain the interior background noise;

[0007] Calculate the characteristic loudness of the corresponding interior background noise under each driving condition of the vehicle, and establish target classification of the interior intake order noise based on the characteristic loudness of the interior background noise;

[0008] Simulate the interior intake order noise of the intake port by the harmonic signal sound generator, so that the frequency and amplitude of the simulated interior intake order noise are the same as those of the corresponding target interior intake order noise;

[0009] Obtain the simulated interior intake order noise, and establish target classification of the intake port order noise according to the simulated interior intake order noise.

[0010] Further, divide the interior noise into interior intake order noise and interior background noise caused by other factors, and obtain the interior background noise, further comprising:

[0011] Silence the intake port of the vehicle to eliminate the interior intake order noise, thereby obtaining the interior background noise caused by other factors.

[0012] Further, calculate the characteristic loudness of the corresponding interior background noise under each driving condition of the vehicle, further comprising:

[0013] Under the idle speed condition, perform discrete Fourier transform on the interior background noise to convert the discrete time domain signal into a frequency domain signal, wherein the discrete Fourier transform formula is:

[0014]

[0015] In the formula, x[n] is the time domain signal of the interior background noise, N is the number of time domain signal points, and X(f) is the noise amplitude at frequency f;

[0016] Based on the interior background noise spectrum X(f), group it by the upper and lower limit frequencies of the 1 / 3 octave band, calculate the sound pressure mean square value in the same 1 / 3 octave band, and convert it into a sound pressure level, and the calculation formula is:

[0017]

[0018] In the formula, L T is the sound pressure level corresponding to the 1 / 3 octave band, p i is the sound pressure at frequency i, and p ref is the reference sound pressure 2×10 -5 pa.

[0019] Further, the sound pressure level in the 1 / 3 octave band is corrected, including low frequency correction, human ear transfer characteristic correction, and auditory threshold correction.

[0020] According to the sound pressure level in the 1 / 3 octave band, the main loudness corresponding to the sound pressure level in the 1 / 3 octave band is calculated, and the calculation formula is:

[0021]

[0022] The center frequency of the 1 / 3 octave band is converted into the critical band Bark domain, and the characteristic loudness corresponding to the in-vehicle background noise is calculated based on the masking effect and the characteristic loudness slope.

[0023] Further, based on the characteristic loudness, the target grading of the in-vehicle intake order noise is made, and further includes:

[0024] Based on the masking effect, when the characteristic loudness of the in-vehicle intake order noise is equal to the characteristic loudness of the in-vehicle background noise, the sound pressure level corresponding to the in-vehicle intake order noise is set as the initial sound pressure, and the human ear has no perception of the in-vehicle intake order noise under the initial sound pressure.

[0025] The perception state of the human ear feeling uncomfortable to the in-vehicle intake order noise is set as poor perception, and multiple levels are set between no perception and poor perception of the in-vehicle intake order noise according to the perception degree, as the target grading of the in-vehicle intake order noise.

[0026] Further, the frequency and amplitude of the in-vehicle intake order noise simulated by the harmonic signal sound generator at the air inlet are the same as the frequency and amplitude of the corresponding target in-vehicle intake order noise, and further includes:

[0027] The mapping relationship between the target in-vehicle intake order noise of each level and the vehicle driving parameter under each driving condition of the vehicle is established.

[0028] The simulated in-vehicle intake order noise at the air inlet under the vehicle driving parameter is the same as the frequency and amplitude of the corresponding target in-vehicle intake order noise.

[0029] Further, the characteristic loudness of the corresponding in-vehicle background noise under each driving condition of the vehicle is calculated, and further includes:

[0030] When the vehicle is in the acceleration or coasting non-steady state condition, the in-vehicle background noise is segmented at a predetermined time interval according to the engine speed change.

[0031] The transient noise signal of acceleration or coasting is approximated as a steady signal.

[0032] The target grading of the in-vehicle intake order noise is set according to the steady signal.

[0033] On the other hand, an inlet order noise target classification device based on a harmonic signal generator is provided, comprising:

[0034] The noise separation module is used to divide the in-vehicle noise into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and to acquire the in-vehicle background noise.

[0035] The target classification module is used to calculate the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and to classify the in-vehicle intake order noise based on the characteristic loudness of the in-vehicle background noise.

[0036] The simulated air intake order noise module is used to simulate the air intake order noise at the air intake so that the frequency and amplitude of the noise transmitted into the vehicle are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level.

[0037] The intake order noise target classification module acquires simulated intake order noise and classifies the intake order noise target based on the simulated intake order noise.

[0038] Furthermore, the noise separation module also includes:

[0039] The noise reduction module silences the vehicle's air intake, eliminating the first-order noise of the air intake and thus capturing the background noise inside the vehicle caused by other factors.

[0040] Furthermore, the simulated intake air order noise module also includes:

[0041] Harmonic signal generator, which generates harmonic noise at the engine order noise frequency, and emits simulated intake order noise through the harmonic generator.

[0042] The adjustment module is used to adjust the frequency and amplitude of the simulated air intake order noise emitted by the harmonic signal generator, so that the frequency and amplitude of the simulated air intake order noise are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level.

[0043] Compared with existing technologies, the beneficial effects of this invention are: separating in-vehicle intake order noise from other noises, preparing for the analysis of the contribution of in-vehicle intake order noise to in-vehicle noise; formulating in-vehicle intake order noise classification targets based on human perception of intake order noise; decomposing in-vehicle intake order noise targets into intake order noise, and further decomposing in-vehicle intake order noise classification targets into intake pipe order noise, thereby decoupling intake noise development from other system noises; realizing the formulation of intake order noise classification targets based on passenger perception, matching intake order noise development targets according to vehicle model positioning, and achieving optimal development in terms of customer perception, cost, weight, and other performance aspects. Attached Figure Description

[0044] Figure 1 This is a flowchart of the method for determining the target classification of air inlet noise based on a harmonic signal generator in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the characteristic response curve of the intake order noise in an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram of octave bands in an embodiment of the present invention;

[0047] Figure 4 This is a schematic diagram of the masking effect in an embodiment of the present invention;

[0048] Figure 5 This is a connection block diagram of the inlet order noise target classification device based on the harmonic signal generator in an embodiment of the present invention;

[0049] In the diagram: 10, Noise separation module; 20, Target classification module; 30, Simulated intake order noise module; 40, Intake order noise target classification module. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0052] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0053] Please refer to the accompanying drawings. This invention provides a technical solution: a method for classifying and determining the target order noise of an air inlet based on a harmonic signal generator, comprising the following steps:

[0054] S102. Divide the in-vehicle noise into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and obtain the in-vehicle background noise.

[0055] Specifically, the in-vehicle noise is divided into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and the in-vehicle background noise is obtained, which also includes:

[0056] The air intake of the vehicle is silenced to eliminate the intake noise inside the vehicle, thereby obtaining the background noise inside the vehicle caused by other factors.

[0057] Among them, the time-domain transfer path analysis (TPA) method is a method for fitting in-vehicle noise to path decomposition. The time-domain TPA system consists of three parts: the excitation source, the transfer path, and the in-vehicle response. The excitation source is the sound pressure signal at the airborne noise source or the excitation force at the active end of the structure-borne noise. The transfer function describes the relationship between the excitation source and the in-vehicle response. The sound pressure at the in-vehicle response point is the vector sum of the excitation source propagating to the in-vehicle along different paths, and its calculation formula is:

[0058]

[0059] In the formula, P response P represents the sound pressure level at the response point inside the vehicle. iair X is the sound pressure level of the i-th airborne path; j H is the excitation force for the j-th structural path; iair H is the transfer function for the i-th air propagation path; jstru The transfer function is used to pass the path to the j-th structure.

[0060] A time-domain propagation path analysis (TPA) model of the vehicle's interior noise was constructed using this method. The model shows that intake noise propagates into the vehicle solely through the airflow path. A large-volume muffler was designed, with a noise reduction capacity more than 10 times that of a traditional intake system. Connecting this large-volume muffler in series with the intake manifold significantly enhances the intake system's noise reduction capacity, resulting in a substantial attenuation of intake-order noise, which then contributes negligibly to the overall interior noise. The interior noise levels before and after connecting the large-volume muffler in series were measured. Subtracting the noise levels under these two conditions yields the intake-order noise. The interior noise measured under the large-volume muffler-connected condition represents the total interior noise caused by other factors, thus achieving separation of intake-order noise from other noise sources.

[0061] Inlet noise is often low-frequency noise, and its frequency components are:

[0062]

[0063] In the formula, z is the number of cylinders; n is the engine speed, r / min; τ is the number of engine strokes, commonly a 4-stroke engine; k is the simple harmonic order, and frequency components with k>3 are generally ignored, with control applied to the first 3 orders of noise.

[0064] Based on the above method for separating the intake noise levels inside the vehicle, the first three main intake noise levels inside the vehicle are separated under various operating conditions, including vehicle idling, idling with air conditioning on, partial load acceleration, full load acceleration, and coasting. The intake noise levels inside the vehicle and the total noise inside the vehicle caused by other factors under each operating condition are obtained, i.e., the background noise inside the vehicle. This prepares for the formulation and evaluation of intake noise level classification targets inside the vehicle.

[0065] S104. Calculate the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and formulate target classification of in-vehicle intake order noise based on the characteristic loudness of the in-vehicle background noise.

[0066] In some environments, when a weak sound and a strong sound are present, the human auditory system only perceives the stronger sound, making the weaker sound difficult to detect. This phenomenon is called the masking effect. Figure 2 As shown, when the characteristic loudness of the intake order noise inside the vehicle is lower than the characteristic loudness of the background noise, the intake order noise is masked by the background noise, and the human ear cannot perceive the intake order noise at this time; conversely, when the characteristic loudness of the intake order noise inside the vehicle is greater than the characteristic loudness of the background noise, the intake order noise cannot be masked by the background noise, and the human ear can perceive the intake order noise at this time; when the characteristic loudness of the intake order noise inside the vehicle is equal to the characteristic loudness of the background noise, the passenger cannot perceive the intake order noise at the corresponding sound pressure level of the intake order noise inside the vehicle.

[0067] The masking effect is one of the most fundamental effects in psychoacoustics. Simply put, it refers to the phenomenon where a sound of one frequency blocks the auditory system from perceiving a sound of another frequency. The former is called the masking tone, and the latter is called the masked tone. When both the masked tone and the masked tone occur simultaneously, and the masked tone is just barely masked, the energy level of the masked tone is called the masking threshold. When the sound level of the masked tone exceeds this masking threshold, the masked tone is partially masked; when it is below the masking threshold, it is completely masked. That is, the masked tone becomes weak or even completely inaudible due to the presence of the masking tone. Figure 3 As shown.

[0068] Specifically, calculating the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions also includes:

[0069] Under idling conditions, a Discrete Fourier Transform (DFT) is performed on the in-vehicle background noise to convert the discrete time-domain signal into a frequency-domain signal. The DFT formula is as follows:

[0070]

[0071] In the formula, x[n] is the time-domain signal of the in-vehicle background noise, N is the number of time-domain signal points, and X(f) is the noise amplitude at frequency f;

[0072] Based on the background noise spectrum X(f) inside the vehicle, it is grouped into upper and lower limits of the 1 / 3 octave band. The mean square value of the sound pressure level within the same 1 / 3 octave band is calculated and converted into the sound pressure level. The calculation formula is as follows:

[0073]

[0074] In the formula, L T To correspond to the 1 / 3 octave band sound pressure level, p i For the sound pressure level at frequency i, p ref Reference sound pressure level 2×10 -5 pa;

[0075] It's understandable that the human ear can hear frequencies ranging from approximately 20 to 20,000 Hz, but sensitivity to different frequencies varies: distinguishing low frequencies is easy, such as 50 Hz and 100 Hz; however, distinguishing high frequencies becomes increasingly difficult, such as 10,000 Hz and 10,050 Hz. Therefore, in spectrum analysis, low frequencies are divided as finely as possible to fully reveal their characteristics for easier analysis; high frequencies are divided as coarsely as possible to blur less sensitive frequency characteristics. This is the idea behind octave band processing. Octaves are commonly used in NVH spectrum analysis, representing a 2:1 ratio between two adjacent frequencies. n The frequency band is a geometric progression, where n represents the number of octaves. This can be illustrated using a combination of numerical and graphical methods. Figure 4 As shown;

[0076] It can be seen that the 1 / 3 octave frequency f u =2 1 / 3 f l ; f u f is the upper limit frequency. l f is the lower limit frequency. T This is the center frequency. The center frequency is usually rounded down; common 1 / 3 octave band frequencies are shown in Table 6.

[0077] Table 6.1 / 3rd Octave Band Frequency

[0078]

[0079]

[0080]

[0081] Specifically, the sound pressure level within one-third of the octave band is corrected, including low-frequency correction, correction of human ear transmission characteristics, and correction of hearing threshold; among which, the center frequency f of each one-third octave band is... T The corresponding correction amounts are shown in Tables 1-3. Table 1 shows the correction amount ΔL for the sound pressure level in the low-frequency 1 / 3 octave band, Table 2 shows the correction amount a0 for the sound pressure level transmitted to the human ear, and Table 3 shows the hearing threshold L. TQ and correction value ΔL CB ;

[0082] Table 1. Correction amount ΔL for sound pressure level in the low-frequency 1 / 3 octave band

[0083]

[0084] Table 2. Sound pressure level correction factor a0 for human ear transmission characteristics

[0085]

[0086]

[0087] Table 3 Hearing Threshold L TQ and correction value ΔL CB

[0088] f T , Hz L TQ ,dB]]> ΔL CB , dB f T , Hz L TQ , dB ΔL CB , dB f T , Hz L TQ ,dB]]> ΔL CB , dB 25 30 -0.25 250 12 -0.8 2500 3 1.7 31.5 30 -0.25 315 8 -0.8 3150 3 1.6 40 30 -0.25 400 7 -0.5 4000 3 1.4 50 30 -0.25 500 6 0.0 5000 3 1.2 63 30 -0.25 630 5 0.5 6300 3 0.8 80 30 -0.25 800 4 1.1 8000 3 0.5 100 18 -0.6 1000 3 1.5 10000 3 0.0 125 18 -0.6 1250 3 1.7 12500 3 -0.5 160 18 -0.6 1600 3 1.8 16000 200 12 -0.8 2000 3 1.8 20000

[0089] Based on the sound pressure level corrected for a 1 / 3 octave band, calculate the principal loudness corresponding to the sound pressure level for a 1 / 3 octave band. The calculation formula is as follows:

[0090]

[0091] The center frequency of 1 / 3 octave band is converted into the critical band Bark domain, and the characteristic loudness corresponding to the background noise inside the vehicle is calculated based on the masking effect and the characteristic loudness slope.

[0092] Table 4 shows the correspondence between the center frequency, critical bandwidth number and critical frequency band; Table 5 shows the characteristic loudness corresponding to the in-vehicle background noise based on the masking effect and characteristic loudness slope.

[0093] Table 4. Correspondence between center frequency, critical bandwidth number, and critical frequency band

[0094]

[0095]

[0096] Table 5 Loudness Slope

[0097]

[0098] Specifically, calculating the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions also includes: when the vehicle is in an unsteady state of acceleration or coasting, the in-vehicle background noise is segmented at a preset time interval of engine speed change;

[0099] The transient noise signal during acceleration or gliding is approximated as a steady-state signal;

[0100] The target classification of in-vehicle intake noise order is set based on steady-state signals.

[0101] For non-steady-state conditions such as vehicle acceleration and coasting, a method based on engine speed slicing is adopted. Preferably, the background noise inside the vehicle is segmented at 50 r / min intervals of engine speed change, and the transient noise signals such as acceleration and coasting are approximated as steady-state signals. Then, the target classification of the intake noise level inside the vehicle is set.

[0102] Specifically, the target classification of in-vehicle intake order noise based on characteristic loudness also includes:

[0103] Based on the masking effect, when the characteristic loudness of the in-vehicle intake order noise is equal to the characteristic loudness of the in-vehicle background noise, the sound pressure level corresponding to the in-vehicle intake order noise is set as the initial sound pressure level. Under the initial sound pressure level, the human ear will not perceive the in-vehicle intake order noise.

[0104] The perception state of discomfort felt by the human ear to the intake noise of the vehicle is defined as poor perception. Multiple levels are set for the human ear's perception of the intake noise of the vehicle, ranging from no perception to poor perception, based on the degree of perception. These levels are used as the target classification settings for the intake noise of the vehicle.

[0105] Among them, such as Figure 2 Taking the characteristic loudness of the noise as an example, when the characteristic loudness of the intake order noise inside the vehicle is lower than the characteristic loudness of the background noise, the intake order noise is masked by the background noise, and the human ear cannot perceive it. Conversely, when the characteristic loudness of the intake order noise inside the vehicle is greater than the characteristic loudness of the background noise, the intake order noise cannot be masked by the background noise, and the human ear can perceive it. When the characteristic loudness of the intake order noise inside the vehicle is equal to the characteristic loudness of the background noise, the sound pressure level corresponding to the intake order noise inside the vehicle... The initial sound pressure level is such that passengers cannot perceive the intake order noise. Based on development experience, when the in-vehicle intake order noise is 8dB higher than the initial sound pressure level, passengers can easily perceive the intake order noise, and the perception is poor. Between the inability to perceive and the poor perception, there are 5 levels to set the target level for in-vehicle intake order noise, which correspond to perception states such as no perception, difficult to perceive, perceptible, easy to perceive, and poor perception, as shown in Table 7. This realizes the hierarchical definition of the whole vehicle's in-vehicle intake order noise target according to different vehicle models and positioning.

[0106] Table 7. Hierarchical Evaluation Based on Masking Effect

[0107]

[0108] S106. The intake order noise of the air intake is simulated by a harmonic signal generator at the air intake so that the frequency and amplitude of the intake order noise transmitted into the vehicle are the same as the frequency and amplitude of the intake order noise of the corresponding target at each level.

[0109] Specifically, the intake noise at the air intake is simulated by a harmonic signal generator so that the frequency and amplitude of the noise transmitted into the vehicle are the same as the frequency and amplitude of the intake noise of the corresponding target levels inside the vehicle. This also includes:

[0110] Establish the mapping relationship between the target in-vehicle intake order noise at each level and the vehicle driving parameters under various driving conditions;

[0111] The simulated intake order noise of the air inlet under the vehicle's driving parameters is made to have the same frequency and amplitude as the in-vehicle intake order noise of the corresponding target at each level.

[0112] Among them, the decomposition of the in-vehicle intake order noise to the intake order noise based on quantitative active sound generation is achieved through active sound generation technology. The principle is to take a traditional fuel vehicle as a carrier and establish a mapping relationship between in-vehicle noise and vehicle speed, pedal opening, assembly output torque, speed and other vehicle driving parameters, as shown in formula (5). By extracting the driving parameters of electric vehicles, the sound that conforms to the frequency and amplitude characteristics of traditional vehicles is synthesized in real time. The power amplifier is driven by the DSP controller to control the speaker to emit the synthesized sound, so that the in-vehicle sound characteristics felt by passengers are consistent with those of traditional fuel vehicles.

[0113]

[0114] In the formula, V is the vehicle speed, n is the motor / engine speed, p is the pedal opening, T is the assembly output torque, ω are the weights of each parameter, H is the sound transfer function from the speaker to the passenger position, and SPL is the in-vehicle sound pressure level.

[0115] In this embodiment, the process of decomposing a quantitative in-vehicle intake order noise into an intake order noise based on an active sound generation method is as follows:

[0116] An active sound generation system is designed, consisting of a loudspeaker, an error microphone, a DSP controller, and an active sound generation algorithm. The loudspeaker is placed in the air filter of the intake system to simulate the process of intake order noise emanating from the intake system. The error microphone is placed at the headrest of the seat, at a distance of (0.2±0.02) m from the center symmetry plane of the seat and (0.7±0.05) m from the seat plane, simulating the noise measurement point inside the vehicle. The DSP is connected to the loudspeaker and the error microphone respectively to realize the acquisition of noise at the target point inside the vehicle and the control of the loudspeaker's sound generation. A harmonic generator is generated using the engine order noise frequency to control the frequency of the sound emitted by the loudspeaker. The search target is to minimize the difference between the error microphone and the target classification of the order noise inside the vehicle, thereby controlling the amplitude of the sound emitted by the loudspeaker, so that the sound transmitted from the loudspeaker to the vehicle is the same as the noise frequency and amplitude of the target classification of the order noise inside the vehicle and the noise from the intake airflow.

[0117] S108. Obtain simulated intake order noise and formulate intake order noise target classification based on simulated intake order noise.

[0118] For example, by placing the vehicle in a anechoic chamber with the engine off, the intake manifold order noise is measured during the above process, thus achieving a quantitative decomposition of the in-vehicle intake order noise into the intake manifold order noise.

[0119] On the other hand, such as Figure 5 As shown, an inlet order noise target classification device based on a harmonic signal generator is provided, comprising:

[0120] The noise separation module 10 is used to divide the in-vehicle noise into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and to acquire the in-vehicle background noise.

[0121] The target classification module 20 is used to calculate the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and to classify the in-vehicle intake order noise based on the characteristic loudness of the in-vehicle background noise.

[0122] The simulated air intake order noise module 30 is used to simulate the air intake order noise at the air intake through a harmonic signal generator, so that the frequency and amplitude of the noise transmitted into the vehicle are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level.

[0123] The intake order noise target classification module 40 acquires simulated intake order noise and classifies the intake order noise target based on the simulated intake order noise.

[0124] Optionally, the noise separation module further includes:

[0125] The noise reduction module silences the vehicle's air intake, eliminating the first-order noise of the air intake and thus capturing the background noise inside the vehicle caused by other factors.

[0126] Optionally, the module simulating intake order noise at the air inlet also includes:

[0127] Harmonic signal generator, which generates harmonic noise at the engine order noise frequency, and emits simulated intake order noise through the harmonic generator.

[0128] The adjustment module is used to adjust the frequency and amplitude of the simulated air intake order noise emitted by the harmonic signal generator, so that the frequency and amplitude of the simulated air intake order noise are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level.

[0129] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for classifying and determining the target order noise of an air inlet based on a harmonic signal generator, characterized in that, include: The in-vehicle noise is divided into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and the in-vehicle background noise is obtained. Calculate the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and formulate a target classification of the in-vehicle intake order noise based on the characteristic loudness of the in-vehicle background noise. The intake air order noise is simulated at the air intake through a harmonic signal generator so that the frequency and amplitude of the intake air order noise transmitted into the vehicle are the same as the frequency and amplitude of the intake air order noise of the corresponding target at each level. In particular, a mapping relationship between the intake air order noise of the target at each level and the vehicle driving parameters is established under each driving condition of the vehicle, so that the simulated intake air order noise at the air intake under the vehicle driving parameters is the same as the frequency and amplitude of the intake air order noise of the corresponding target at each level. The simulated intake order noise is obtained, and the intake order noise target classification is formulated based on the simulated intake order noise.

2. The method for classifying and determining the intake order noise target based on a harmonic signal generator according to claim 1, characterized in that, The interior noise is divided into intake noise and background noise caused by other factors. The background noise is also obtained, including: The air intake of the vehicle is silenced to eliminate the intake noise inside the vehicle, thereby obtaining the background noise inside the vehicle caused by other factors.

3. The method for classifying and determining the intake order noise target based on a harmonic signal generator according to claim 1, characterized in that, Calculating the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions also includes: Under idling conditions, a Discrete Fourier Transform (DFT) is performed on the in-vehicle background noise to convert the discrete time-domain signal into a frequency-domain signal. The DFT formula is as follows: In the formula, x[n] is the time-domain signal of the in-vehicle background noise, N is the number of time-domain signal points, and X(f) is the noise amplitude at frequency f; Based on the background noise spectrum X(f) inside the vehicle, it is grouped into upper and lower limits of the 1 / 3 octave band. The mean square value of the sound pressure level within the same 1 / 3 octave band is calculated and converted into the sound pressure level. The calculation formula is as follows: In the formula, L T To correspond to the 1 / 3 octave band sound pressure level, p i For the sound pressure level at frequency i, p ref Reference sound pressure level 2×10 -5 pa.

4. The method for classifying and determining the intake order noise target based on a harmonic signal generator according to claim 3, characterized in that, include: The sound pressure level within 1 / 3 octave band is corrected, including low-frequency correction, human ear transmission characteristics correction, and hearing threshold correction. Based on the sound pressure level corrected for a 1 / 3 octave band, calculate the principal loudness corresponding to the sound pressure level for a 1 / 3 octave band. The calculation formula is as follows: The center frequency of 1 / 3 octave band is converted into the critical band Bark domain, and the characteristic loudness corresponding to the background noise inside the vehicle is calculated based on the masking effect and the characteristic loudness slope.

5. The method for classifying and determining the intake order noise target based on a harmonic signal generator according to claim 1, characterized in that, Target classification of in-vehicle intake noise based on characteristic loudness also includes: Based on the masking effect, when the characteristic loudness of the in-vehicle intake order noise is equal to the characteristic loudness of the in-vehicle background noise, the sound pressure level corresponding to the in-vehicle intake order noise is set as the initial sound pressure level. Under the initial sound pressure level, the human ear will not perceive the in-vehicle intake order noise. The perception state of discomfort felt by the human ear to the intake noise of the vehicle is defined as poor perception. Multiple levels are set for the human ear's perception of the intake noise of the vehicle, ranging from no perception to poor perception, as the target classification of intake noise of the vehicle.

6. The method for classifying and determining the intake order noise target based on a harmonic signal generator according to claim 1, characterized in that, Calculating the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions also includes: When the vehicle is in an unsteady state of acceleration or coasting, the background noise inside the vehicle is segmented at preset time intervals based on the engine speed change. The transient noise signal during acceleration or gliding is approximated as a steady-state signal; The target classification of in-vehicle intake noise order is set based on steady-state signals.

7. An inlet order noise target classification device based on a harmonic signal generator, employing the inlet order noise target classification method based on a harmonic signal generator as described in any one of claims 1 to 6, characterized in that, include: The noise separation module is used to divide the in-vehicle noise into in-vehicle intake order noise and in-vehicle background noise caused by other factors, and to acquire the in-vehicle background noise. The target classification module is used to calculate the characteristic loudness of the corresponding in-vehicle background noise under various driving conditions, and to classify the in-vehicle intake order noise based on the characteristic loudness of the in-vehicle background noise. The simulated air intake order noise module is used to simulate the air intake order noise at the air intake so that the frequency and amplitude of the noise transmitted into the vehicle are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level. The intake order noise target classification module acquires simulated intake order noise and classifies the intake order noise target based on the simulated intake order noise.

8. The inlet order noise target classification device based on a harmonic signal generator according to claim 7, characterized in that, The noise separation module also includes: The noise reduction module silences the vehicle's air intake, eliminating the first-order noise of the air intake and thus capturing the background noise inside the vehicle caused by other factors.

9. The inlet order noise target classification device based on a harmonic signal generator according to claim 7, characterized in that, The simulated intake order noise module also includes: Harmonic signal generator, which generates harmonic noise at the engine order noise frequency, and emits simulated intake order noise through the harmonic generator. The adjustment module is used to adjust the frequency and amplitude of the simulated air intake order noise emitted by the harmonic signal generator, so that the frequency and amplitude of the simulated air intake order noise are the same as the frequency and amplitude of the in-vehicle air intake order noise of the corresponding target at each level.

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