157 results about "Sound power" patented technology

The invention relates to the technical field of permanent magnet synchronous motors, in particular to a method, device and equipment for reducing vibration noise of a permanent magnet synchronous motor, and the method comprises the steps: building an electromagnetic field model, extracting radial electromagnetic force data, carrying out the spectrum and modal analysis, recognizing a main noise source, generating an acoustic power level waterfall plot through the combination of acoustic simulation, and defining an optimization target. The optimal scheme is finally obtained by designing the shape of a rotor hole, adjusting multi-parameter collaborative optimization of stator slot width and air gap length and the like, and iteratively optimizing key variables by adopting an intelligent algorithm. According to the method, the space 0-order quadruplicated frequency noise and 24-order octupled frequency noise are remarkably reduced, the torque fluctuation is inhibited, the output performance is ensured, the method is suitable for large-scale production, and the NVH quality of the motor is effectively improved.

The invention relates to the technical field of acoustic imaging, and discloses an acoustic imaging system of a concentric-circle nested microphone array, which comprises a central microphone and the concentric-circle nested microphone array. The concentric nested microphone arrays are concentrically arranged by taking the central microphone as the center, a plurality of microphones are distributed on each layer of circular microphone array according to a nested array rule, and the distance between each layer of adjacent microphone arrays is d. By adopting a unique circular nested microphone array structure, the position information of a sound source can be accurately captured through the cooperative work of multiple layers of microphone arrays. A plurality of microphones are distributed in each layer of microphone array in a circular nested array, a multi-dimensional sound acquisition network is formed by combining a central microphone, and meanwhile, the signal processing module gradually extracts and reconstructs sound source information in a sound field by utilizing a CLEAN-SC algorithm and through iterative decomposition and removal of strongest components in sound source signals, so that a sidelobe interference image is effectively inhibited, and the sound quality is improved. Therefore, a high-resolution sound power distribution diagram is obtained, and acoustic imaging is realized.

The invention provides a wave finite element and boundary element mixed composite board structure sound insulation performance prediction method, and the method belongs to the acoustics field, and comprises the steps: carrying out the post-processing of a wave finite element model based on the wave finite element model of a composite board structure and a corresponding equivalent nodal force, and obtaining the wave finite element equation of the whole composite board structure; based on a sound-structure coupling equation, through a boundary element method, a discrete boundary element equation related to the surface vibration speed of the composite board and the radiation sound wave pressure is constructed; coupling the wave finite element equation and the discrete boundary element equation of the whole composite board structure, and determining the sound pressure of radiation sound waves of the composite board structure and the surface vibration speed of the composite board; and based on the sound pressure of the radiation sound wave of the composite board structure and the surface vibration speed of the composite board, obtaining a sound insulation performance prediction result by calculating the sound power of the incident sound wave and the radiation sound wave, and completing prediction of the sound insulation performance of the composite board structure. The problems that the sound transmission loss of large plates and medium-high frequency plates is difficult to predict and the calculation cost is high are solved.

The invention provides a vector array sparse Bayesian learning direction of arrival estimation method. The method comprises the following steps: constructing a far-field vector sparse signal model; and establishing a noise covariance model under the vector sound field. And estimating a signal power hyper-parameter through a vector array sparse Bayesian learning process. And through a maximum likelihood estimation technology, noise power hyper-parameter estimation is realized. And finally, carrying out peak searching on the converged signal power hyper-parameter to obtain a direction of arrival estimation result. The method has the advantages that the vector array signal processing performance advantage is obtained, higher signal processing gain is obtained, and meanwhile the method has the capability of restraining the azimuth ambiguity problem; and by using the difference between the noise covariance matrix and the signal covariance matrix under the vector noise, the estimation precision of hyper-parameters such as the signal power and the noise power is remarkably improved. Compared with a traditional vector array DOA estimation method, the vector array DOA estimation method has a lower spectrum background and a sharper spatial spectrum peak, and the resolution and DOA estimation precision are remarkably superior to those of other methods.

The invention relates to a noise simulation testing method and device of a vehicle and electronic equipment, and relates to the technical field of vehicles, in particular to the technical field of simulation testing, and the method comprises the steps: obtaining the sound power level data of a bench test of a to-be-tested electric drive system; constructing a noise simulation model of the target vehicle, and determining an electric drive noise excitation source in the noise simulation model based on the sound power level data; and performing a noise simulation test based on the noise simulation model to obtain a noise simulation test result. The noise excitation source in the electric drive shell is determined based on the bench test result, electric drive actual excitation of the vehicle under different working conditions can be better reflected, and then the accuracy of the noise simulation result is improved.

The invention discloses a woodworking machine tool noise sound power level measurement method based on a sound intensity method, and belongs to the technical field of machine tool noise measurement, and the method specifically comprises the steps: determining a housing surface covered by a tool rotation plane projection as a main sound radiation region, and determining a main bearing pedestal installation surface as an infrasound radiation region; sound pressure, vibration acceleration signals and dynamic air pressure signals of a main sound radiation area are collected; resampling a dynamic air pressure signal rotation angle domain, extracting a reference pneumatic pulsating waveform synchronous with tool tooth sweeping, and establishing an airflow induced sound pressure model according to the reference pneumatic pulsating waveform and a phase relation; calculating a surface normal vibration speed according to the vibration acceleration, and establishing a structure radiation sound pressure model in combination with a sound wave equation; decomposing the sound pressure signal to obtain two types of component estimation values, and performing parameter optimization to obtain net sound intensity of a main sound radiation area; extracting vibration frequency band energy of an infrasound radiation area, calculating equivalent sound intensity by combining a sound radiation efficiency model, and outputting a total sound power level by space integration; the invention provides an effective method for accurately measuring and controlling the noise of the woodworking machine tool.

The invention discloses a sound power adjusting system based on vehicle-mounted battery state self-adaption, and relates to the technical field of automobile electronic control, and the system comprises a vehicle state sensing and data collection module which is used for analyzing a bus message to obtain a power parameter and a load state, and collecting a battery physical parameter; the decision and strategy control module is connected to the sensing module and is used for calculating a sound equipment allowable output power threshold value under the current working condition and generating a control instruction according to the power priority mapping table and a battery state power calculation model; the execution and audio processing module is used for adjusting the carrier frequency and gain of a power amplifier according to the instruction and executing audio frequency band processing; and the cross-domain isolation power supply protection module is used for providing isolation power supply and switching to the emergency energy storage element when the voltage drops. Through a load preloading mechanism and dynamic internal resistance evaluation, adaptive matching of the sound power and the vehicle battery state is realized, and the system is effectively prevented from resetting due to voltage drop.

The invention discloses a current harmonic injection optimizing method and electronic equipment. The method comprises the following steps: determining a harmonic optimization working condition point; experimental data of sound power of the driving system and current harmonic combination of a controller of the driving system under the harmonic optimization working condition point are obtained, a function relation of the sound power and the current harmonic combination under the harmonic optimization working condition point is established based on the experimental data, and the current harmonic combination comprises single-time or multi-time current harmonic parameters; solving a current harmonic combination corresponding to a minimum value of the sound power as an optimal current harmonic combination from a function relationship between the sound power and the current harmonic combination under the harmonic optimization working condition point; and injecting the optimal current harmonic combination into a controller. The method can help to perform optimization control on the order noise of the motor at the initial development stage of the motor, the gearbox (a driving unit) and the whole vehicle (when no real vehicle resources exist), and a good level of noise is achieved. According to the method, the development period is shortened through the efficient method, and unnecessary engineering changes in the later period of development are avoided.

The invention discloses an underwater structure low-frequency radiation sound power forecasting method based on blind source separation, and the method comprises the following steps: (1), setting a housing sound source in a shallow sea environment, and obtaining discrete sound pressure; (2) obtaining an estimation signal of the source signal through a blind source separation algorithm; (3) windowing the estimated signal space data of the source signal in the z direction to obtain the sound pressure propagating outwards after windowing; (4) the sound pressure propagating outwards is converted into a wave number domain through discrete space Fourier transform, and a holographic surface sound pressure cylindrical wave spectrum is obtained; (5) filtering evanescent waves in a wavenumber domain by using a wavenumber domain filter to obtain propagation waves on a holographic surface; (6) transmitting the filtered sound pressure to a far field in a spherical shape through a near-field acoustical holography technology by means of stable-phase estimation; (7) deducing the sound intensity by using the far-field sound pressure so as to obtain the radiation sound power; according to the invention, the measurement workload is reduced; measurement is carried out on a holographic surface close to a sound source, the influence of boundary reflection is small, and a calculation result is accurate.

The present invention provides a method and system for predicting cab noise, relating to the technical field of vehicle strength analysis. The method comprises: when a physical cab or a cab model is available, obtaining the vibration-acoustic transfer function from each cab mounting point to the driver's position through different methods, obtaining the mounting point load under different operating conditions, obtaining the sound-acoustic transfer function from the cab sound source to the driver's position through different methods, and performing sound power level testing on each cab sound source to obtain the sound source load of the cab sound source; combining the vibration-acoustic transfer function and the mounting point load to generate structure-borne sound; combining the sound-acoustic transfer function and the cab sound source load to generate airborne sound; and synthesizing the cab noise based on the structure-borne sound and airborne sound. The present invention can more quickly and accurately determine cab noise.

The application relates to a real-valued super-resolution direction estimation method of a high-order acoustic field sensor array, which uses a received signal covariance matrix to approximately calculate an estimated value of noise power, avoids the iterative operation process of noise power in the prior art, improves the calculation efficiency, and reduces the floating-point operation amount. By constructing an augmented matrix, the array receiving data matrix and the array manifold matrix with a multi-dimensional structure of an element are made into Hermitian matrices, so that the unitary transformation processing of the related parameters of the high-order acoustic field sensor array is realized. On the basis of obtaining the array receiving data matrix and the array manifold matrix in the real number domain, the array receiving data matrix and the array manifold matrix are applied to a sparse approximate minimum variance method with a variable exponential factor, and the completely real-valued sparse approximate minimum variance direction estimation with a variable exponential factor is realized.

The application relates to a noise simulation test method and device of a vehicle and electronic equipment, relates to the technical field of vehicles, in particular to the technical field of simulation tests, and comprises the following steps: obtaining sound power level data of bench test of an electric drive system to be tested; constructing a noise simulation model of a target vehicle, determining an electric drive noise excitation source in the noise simulation model based on the sound power level data; performing noise simulation test based on the noise simulation model to obtain a noise simulation test result. The noise excitation source inside the electric drive shell is determined based on the bench test result, the actual excitation of the electric drive under different working conditions of the vehicle can be better reflected, and the accuracy of the noise simulation result is improved.

The invention relates to a thermoacoustic machine (1) comprising a control device (14) configured to modulate the acoustic power generated by one or more acoustic sources (6-9) so that the temperature of an external source (2) connected to one or more thermoacoustic cells (10-13) of the machine (1) reaches or remains substantially the same as a setpoint temperature. Figure for the abstract: Fig. 1

1. The name of the design product: solar Bluetooth sound power (K035). 2. The use of the design product: for energy storage, the product can also be used to play audio. 3. The design points of the design product: in shape. 4. The picture or photo that best indicates the design points: perspective view.

The present invention discloses a welding gun head suitable for small-angle narrow slits. The inner diameter of the air outlet of the protective sleeve of the welding gun head is 9-11 mm, and the outer diameter is 12-14 mm; a plurality of circular holes evenly distributed in the circumferential direction are provided at the cross-section of the protective sleeve close to the air outlet of the protective sleeve. On the premise of ensuring that the length of the welding wire extending out of the contact tip is qualified, the present invention reduces the diameter of the hollow frustum of the protective sleeve, so that the welding gun head can extend deeper into the weld; noise reduction circular holes are provided on the protective sleeve, and the size and position of the noise reduction circular holes punched on the protective sleeve are optimized and calculated according to the design requirements of the total sound power of the jet noise, and then the punching is accurately implemented, so that the total sound power of the jet noise accurately meets the design requirements, reduces the speed and pressure of the argon jet at the air outlet of the protective sleeve, eliminates the discrete noise caused by the huge instantaneous pressure change in the jet mixing zone, and effectively eliminates the high-frequency noise during the welding process.

The application relates to the technical field of aluminum processing supervision, in particular to a generation method of an aluminum leakage judgment model, an aluminum leakage detection method and equipment, which comprises the following steps: acquiring a first acoustic fingerprint signal and noise power spectral density under a casting state without aluminum leakage; acquiring a second acoustic fingerprint signal and environmental sound power spectral density under the casting state with aluminum leakage; calculating a noise suppression gain function; acquiring a training acoustic fingerprint signal and extracting casting acoustic fingerprint features based on the noise suppression gain function; classifying the casting acoustic fingerprint features to acquire non-aluminum leakage feature labels and aluminum leakage feature labels, and training to obtain an aluminum leakage judgment model; collecting real-time acoustic fingerprint signals under the casting state and obtaining real-time acoustic fingerprint features; inputting the real-time acoustic fingerprint features into the aluminum leakage judgment model and waiting for output judgment results; if the judgment results correspond to the aluminum leakage feature labels, it is determined that aluminum leakage is determined and alarm information is output. The application is used for improving aluminum leakage detection effects in a multi-noise environment.

The invention relates to the technical field of power generation devices, and provides a nuclear fuel built-in loop free piston thermo-acoustic generator which comprises a thermo-acoustic engine, a control drum, a neutron reflecting layer and a piston type generator, the thermo-acoustic engine comprises a low-temperature heat exchanger, a heat regenerator and a reactor core which are arranged in sequence, and the reactor core is provided with a channel for working medium gas to circulate; the control drum is arranged on the peripheral side of the thermoacoustic engine; the thermoacoustic engine and the control drum are both arranged in the neutron reflecting layer, the piston type generator is provided with a main piston air cylinder, the main piston air cylinder is in acoustic communication with the outlet end of the thermoacoustic engine through an expansion cavity side resonance tube, and the piston type generator is used for converting part of acoustic power into electric energy and adjusting the acoustic impedance phase angle. The reactor core is directly used as a heat source to be arranged in the thermoacoustic engine, so that the reactor core directly replaces a hot end heat exchanger in the traditional technology, the arrangement of a middle heat transfer structure is avoided, the structure is simple, and the problem of low heat transfer efficiency caused by the heat transfer structure is avoided.

The invention relates to the technical field of environmental acoustics, discloses a road totally-enclosed sound barrier sound field prediction method and system, belongs to the field of environmental acoustics, and has very high practicability in sound field prediction and noise pollution evaluation of public road traffic noise after a totally-enclosed sound barrier is implemented. On the basis of the acoustic propagation principle, a new prediction method is provided for a road traffic noise source and a totally-closed sound barrier, a sound field is divided into two subsystems including a barrier internal space and an external space, and equivalent acoustic models of the two subsystems and a calculation method and recommendation parameters of the noise source sound power level are given respectively. According to the method, the sound environment of the high-rise building close to the urban road can be accurately predicted and calculated, and a basis is provided for noise pollution evaluation and control. And meanwhile, the method can be matched with a national standard method or commercial acoustic software for use, and has relatively high applicability.

A vehicle abnormal sound identification method, system and device and a computer readable storage medium relate to the field of vehicle abnormal sound detection, and specifically comprise the following steps: determining a weighting coefficient corresponding to each 1 / 6 frequency band based on a weighting coefficient of a 1 / 3 frequency band corresponding to target vehicle noise data; obtaining a target noise characteristic curve and a non-target noise characteristic curve corresponding to each 1 / 6 frequency band; determining a second distance based on a first distance between a target upper limit curve of the target noise characteristic curve and the target noise characteristic curve, the first weighting coefficient and the second weighting coefficient; determining a first upper limit curve of the non-target noise characteristic curve based on the second distance and the non-target noise characteristic curve; and carrying out abnormal sound identification on the target vehicle based on the position relationship between the target noise characteristic curve and the target upper limit curve and the position relationship between the non-target noise characteristic curve and the first upper limit curve. The problem that abnormal sound with low sound power and / or narrow frequency band cannot be effectively identified in the prior art is solved.

The present application relates to the field of sound field measurement of medical ultrasonic diagnostic equipment, and particularly relates to a sound mask for limiting square area sound power measurement and a preparation method thereof. The sound mask comprises: a first absorbing layer, a reflecting layer, an intermediate layer and a second absorbing layer which are sequentially stacked from top to bottom; the reflecting layer is located at the central region of the first absorbing layer, the intermediate layer and the second absorbing layer, and a square sound transmission hole penetrating through the thickness of the reflecting layer is formed on the reflecting layer; the first absorbing layer, the reflecting layer, the intermediate layer and the second absorbing layer are tightly adhered through a pouring process to form an integral plate structure. The present application reasonably arranges the mask structure of the sound mask by establishing a theoretical model of sound wave vertical incidence multi-layer medium, so that the sound beam can be constrained, and the performance of the sound mask can strictly meet the technical requirements of the industry standard YY / T1084-2015.

The present disclosure relates to a method and device for acoustically imaging fan noise, an electric vehicle charging pile, and a storage medium. The method comprises: acquiring a noise time-domain signal generated by a fan when the fan is running; performing time-frequency conversion on the noise time-domain signal based on a short-time Fourier transform algorithm to obtain a noise frequency-domain signal; inputting the noise frequency-domain signal into a delay-and-sum beamformer to perform beamforming to obtain beam data; positioning principal component data of the beam data to obtain sound power data; and generating a sound image containing a sound source position according to the sound power data. In this embodiment, the resolution of the noise can be improved by positioning the principal component of the beam data, which achieves the effect of accurately positioning the sound source position and is conducive to obtaining a more accurate sound image.

This invention discloses a method for measuring the sound power level of woodworking machine tool noise based on the sound intensity method, belonging to the field of machine tool noise measurement technology. Specifically, it includes: determining the housing surface covered by the projection of the tool's rotation plane as the main sound radiation area, and the main bearing seat mounting surface as the secondary sound radiation area; acquiring sound pressure, vibration acceleration signals, and dynamic air pressure signals in the main sound radiation area; resampling the dynamic air pressure signal in the rotational angular domain, extracting the reference air pulse waveform synchronized with the tool tooth sweep, and establishing an airflow-induced sound pressure model based on this and the phase relationship; calculating the surface normal vibration velocity based on the vibration acceleration, and establishing a structural radiation sound pressure model based on the sound wave equation; decomposing the sound pressure signal to obtain estimates of two types of components, and obtaining the net sound intensity of the main sound radiation area after parameter optimization; extracting the vibration frequency band energy of the secondary sound radiation area, calculating the equivalent sound intensity based on the sound radiation efficiency model, and spatially integrating to output the total sound power level. This invention provides an effective method for the accurate measurement and control of woodworking machine tool noise.

An exhaust plume control structure includes a mounting member configured to mount to an exhaust flow source. A diverter member is coupled to the mounting member to radially direct an initial exhaust flow exiting from the exhaust flow source radially outward. A plurality of peripherally spaced, radially extending vanes are coupled to the mounting member and radially outward of the diverter member to separate the radially outward directed initial exhaust flow into a plurality of additional exhaust flows. Each vane has a radially diverging cross-section. Each of the plurality of additional exhaust flows has a same radial exit velocity. The structure reduces exhaust flow velocity and may provide back pressure to the initial exhaust flow. The structure has a sound power level of less than 115 dBA. A power generating plant including the structure is also disclosed.

The invention relates to a rocket takeoff jet flow noise prediction method and system containing multistage water spraying, and belongs to the technical field of aerospace transportation systems.The takeoff jet flow is dispersed into a series of independent point sound sources, sound power and sound radiation characteristics of the point sound sources are established respectively, meanwhile, a control volume is delimited in a jet flow water spraying area, and the control volume is calculated; the jet flow parameter ratio before and after water spraying is calculated, the sound power and radiation characteristics of the point sound source after water spraying are obtained through calculation, and then takeoff jet flow noise after water spraying is obtained; according to the method, takeoff jet noise prediction under different water spraying parameters can be realized, and reference is provided for noise environment design and water spraying scheme design; according to the rocket takeoff jet flow sound source distribution and the rocket takeoff water spraying position, the deflection jet flow noise radiation characteristic and the effective water spraying rate are obtained, the total sound pressure level precision at the takeoff noise peak moment is predicted to be superior to 3dB, the prediction precision of the peak frequency band of the 1 / 3 octave spectrum at the peak moment is predicted to be superior to 3dB, and the method has important engineering application and popularization value.

The application discloses a transformer load noise calculation method and system, and the method comprises the following steps: S1, modal test is carried out on a transformer coil under inherent compression force of the transformer coil, and modal test parameters are obtained; S2, an equivalent model of the transformer coil is established, modal simulation is carried out on the equivalent model of the transformer coil, and modal simulation parameters are obtained; S3, the modal test parameters and the modal simulation parameters are compared, and equivalent material parameter values are determined; S4, a mapping relationship between the compression force and the equivalent material parameter values is established; S5, the electric power of the transformer coil is obtained by adopting three-dimensional magnetic field simulation; S6, the vibration amplitude of the transformer coil is calculated; S7, noise energy generated by the transformer coil is calculated; and S8, the sound power level of the transformer load is calculated. The mapping relationship between the compression force, material characteristics, vibration response and noise radiation is established, and more accurate load noise calculation is realized.

The present invention belongs to the technical field of functional ceramic materials, and discloses a method for preparing porous piezoelectric ceramic materials and a preparation device thereof. The method comprises: step S1: preparing a porous material forming slurry by mixing; step S2: using a power ultrasonic transducer to emit ultrasonic waves to generate a cavitation effect, generating microbubbles during the slurry forming process, and regulating the sound field distribution and motion trajectory, sound power intensity and frequency of the power ultrasonic transducer, thereby regulating the position and morphology of the microbubbles generated by cavitation; step S3: curing the slurry to obtain a porous material blank; step S4: heat-treating the porous material blank to obtain a porous material. The porous piezoelectric ceramic material prepared by the above method of the present invention has good performance, can realize customized production, has low production cost, high efficiency, and environmentally friendly production, and is conducive to the preparation of functional materials with specific acoustic properties and energy storage properties, and is also conducive to the preparation of porous composite materials with more complex external structures.

The utility model discloses a positioning assembly and an ultrasonic power meter, and relates to the technical field of ultrasonic power meters, the ultrasonic power meter comprises a sound absorption water tank and a conical target, the positioning assembly comprises a main body structure, a first positioning structure and a second positioning structure, and the main body structure is used for bearing the sound absorption water tank and the conical target; the first positioning structure is arranged on the main body structure and used for being in positioning fit with the sound absorption water tank; the second positioning structure is arranged on the main body structure and is used for being in positioning fit with the conical target, so that the central axis of the conical target and the central axis of the sound absorption water tank are coaxially aligned; according to the technical scheme of the utility model, the test efficiency of the ultrasonic power meter can be improved.

This invention discloses an artificial intelligence-based design method for the sound insulation and noise reduction enclosure structure of converter stations, specifically relating to the field of converter station noise control. It addresses the problems of low-frequency control difficulties and noise leakage from ventilation openings leading to mismatch between the design scheme and station boundary targets in converter station enclosure structure design. The method involves obtaining equivalent continuous sound levels at representative points at the station boundary according to specifications and recording equipment operating status. These levels are then compared with existing predicted sound levels of the same diameter to obtain source term corrections, generating an equivalent sound power parameter set. Combining ventilation and heat dissipation constraints with the station's layout boundary calculation criteria, machine learning is used to comprehensively obtain the governance allocation coefficient. This guides the retrieval of the enclosure unit library to generate candidate enclosure combinations and matching opening noise reduction configurations. Finally, sound field and thermal ventilation checks are performed to output a constructable layout and node details, improving design feasibility and consistency.

The invention relates to a water-bearing household appliance (1), in particular a dishwasher, with a circulation pump (23) for washing liquid (F) operated at a current pump speed (n1), a temperature sensor (36) for detecting a temperature value (T) of the washing liquid (F), and a determination unit (37) for determining a further pump speed (n2) of the circulation pump (23) as a function of the detected temperature value (T) and the current pump speed (n1), wherein the determination unit (37) is configured to determine the further pump speed (n2) in such a way that a further sound power level of the water-bearing household appliance (1) resulting at the determined further pump speed (n2) is below a target sound power level (SLP).

The present invention relates to the technical field of electrical digital data processing, and proposes an injector optimization method and system based on an improved orthogonal test method, which combines the advantages of computational fluid dynamics simulation, neural network modeling, and multi-objective optimization algorithms. First, the flow field and acoustic field characteristics of the injector are accurately simulated through a simulation model, providing high-quality data support for optimization. Secondly, an improved orthogonal test method is used for decision variable identification and data augmentation, improving the training effect of the neural network model. Finally, the NSGA-II genetic algorithm is used for multi-objective optimization, enabling the performance of the injector to achieve a balance among multiple objectives. The optimized injector shows significant advantages in terms of velocity distribution, turbulent kinetic energy, and sound power level. After optimization, the flow loss is reduced, the air flow expansion state is improved, the vacuum degree is increased, and at the same time, the flow noise is effectively reduced, enabling the injector to have higher working efficiency and better performance.