Automobile pressure release valve noise control method based on local resonance acoustic superstructure

Abstract

The invention relates to the technical field of automobile interior noise control, in particular to an automobile pressure release valve noise control method based on a local resonance acoustic superstructure. The method comprises the steps of obtaining basic data of a target vehicle; carrying out multi-working-condition noise testing based on the basic data of the target vehicle, and determining a main noise frequency; a main radiation source of pressure release valve noise is positioned based on the main noise frequency, and a key path of noise propagation in a vehicle is analyzed; extracting a noise main peak frequency based on the main noise frequency, the main radiation source and the key path, and determining a core noise reduction frequency band; setting a noise reduction target based on the core noise reduction frequency band; constructing a three-dimensional finite element model of the acoustic superstructure based on the basic form of the superstructure; inputting the acoustic superstructure part into the three-dimensional finite element model for simulation analysis; and a simulation analysis result is compared with an initial test result of the target vehicle, a noise reduction effect is analyzed, and the superstructure part is optimized. The sound absorption and insulation structure for specific frequency noise can be designed according to noise sources at the positions of different vehicle types.

Description

Technical Field

[0001] This invention relates to the field of automotive in-vehicle noise control technology, and in particular to a method for controlling the noise of automotive pressure relief valves based on local resonant acoustic superstructures; it provides a method for controlling the noise of vehicle pressure relief valves based on the principle of acoustic superstructures; and it can design sound-absorbing and sound-insulating structures for noise of specific frequencies for noise sources at this location in different vehicle models. Background Technology

[0002] The pressure relief valve is a crucial component of a vehicle, serving functions such as balancing the pressure difference between the passenger compartment and the outside, and preventing fogging and frost formation on the windows. However, its connection to the outside of the passenger compartment also makes it a significant weakness in vehicle sound insulation. With the continuous development of new energy vehicles, the lack of engine masking effect places higher demands on the overall sound absorption and insulation performance of the vehicle. Due to the structural requirements and layout of various systems, most vehicles place the pressure relief valve at the rear side panel. This location is close to numerous noise sources, including the rear wheels, exhaust system, and air spring reservoir, making sound insulation in this area extremely important. Therefore, finding a method that does not affect the ventilation effect of the pressure relief valve while preventing noise from entering the passenger compartment through it is of paramount importance.

[0003] Prior art 1, Chinese Patent Application No. 202510539993.8, discloses a method, device, equipment, storage medium, and product for predicting aerodynamic noise in a vehicle. The method includes: determining the aerodynamic noise prediction result of a commercial vehicle under external noise sources; the external noise sources include air conditioning vents and pressure relief valves; based on the noise prediction result of the external noise sources, performing aerodynamic noise transmission analysis on the sealing and sound insulation systems of the commercial vehicle to determine the aerodynamic noise transmission result; based on the aerodynamic noise transmission result and the aerodynamic noise prediction result of the air conditioning vents and pressure relief valves, performing aerodynamic noise transmission analysis on the sound absorption system of the driver's cabin of the commercial vehicle to determine the predicted aerodynamic noise response of the entire vehicle at the driver's ear. Although the technical solution of this embodiment improves the accuracy of predicting, simulating, or modeling the aerodynamic noise response at the driver's ear during vehicle operation, adding an acoustic barrier between the external sheet metal and the rear bumper lengthens the sound transmission path of noise entering the vehicle at that location, reducing the amount of noise entering the vehicle.

[0004] Prior art 2, Chinese patent application number: 202411549133.4, relates to the field of vibration reduction and noise reduction technology for pipeline systems, and provides an active silencer pressure relief valve, including: a valve body forming an inlet chamber and a pressure relief chamber that are interconnected; a bypass pipe communicating with the inlet chamber; a piezoelectric actuator and a pressure relief assembly, the pressure relief assembly including an adjusting member, a pressure relief elastic member, and a pressure relief valve core, the pressure relief valve core and the pressure relief elastic member being disposed in the pressure relief chamber, the adjusting member being movably disposed on the valve body, the piezoelectric actuator being disposed on the adjusting member, and the pressure relief elastic member being pressed between the piezoelectric actuator and the pressure relief valve core; the piezoelectric actuator is configured to drive the pressure relief elastic member to eliminate transient noise caused by pulsating pressure when the pressure relief valve core moves. Although the provided active noise-reducing pressure relief valve, by arranging piezoelectric actuators, introduces active noise reduction technology into the pulsating noise control of the active noise-reducing pressure relief valve, and can adjust the force applied to the pressure relief valve core through the pressure relief elastic element to eliminate the transient noise caused by pulsating pressure when the pressure relief valve core moves; however, the sound-absorbing material pasted on the rear bumper of the vehicle opposite the ventilation window can only absorb part of the high-frequency noise; it cannot completely block it, and the ventilation performance of the pressure relief valve needs to be considered to ensure the defogging and defrosting performance of the windows.

[0005] Prior art three, Chinese patent application number: 202411552526.0, provides a pressure relief valve with active noise reduction function, including: a valve body forming an inlet chamber and a pressure relief chamber that are interconnected; a bypass pipe communicating with the inlet chamber; a pressure relief assembly including an adjusting member, a pressure relief elastic member, and a pressure relief valve core, the pressure relief valve core and the pressure relief elastic member being disposed in the pressure relief chamber, the adjusting member being movably disposed on the valve body, and the pressure relief elastic member being pressed between the adjusting member and the pressure relief valve core; a piezoelectric actuator and a noise reduction elastic member, the piezoelectric actuator being disposed on the inlet chamber, and the noise reduction elastic member being pressed between the drive end of the piezoelectric actuator and the pressure relief valve core, the piezoelectric actuator being configured to drive the noise reduction elastic member. Although the provided pressure relief valve with active noise reduction function introduces active noise reduction technology into the pressure relief valve pulsation noise control by arranging piezoelectric actuators, and can adjust the force applied to the pressure relief valve core through noise reduction elastic elements to eliminate transient noise caused by pulsating pressure when the pressure relief valve core moves; however, arranging a sound insulation cover on the pressure relief valve in the vehicle and attaching sound-absorbing material to the sound insulation cover requires multiple openings to ensure ventilation area, and most sound-absorbing materials can only absorb a portion of high-frequency noise.

[0006] Currently, existing technologies 1, 2, and 3 suffer from problems such as low ventilation performance of the pressure relief valve, only being able to absorb a portion of high-frequency noise, and the need for multiple openings in the soundproof enclosure. Therefore, this invention provides a noise control method for automotive pressure relief valves based on a local resonant acoustic superstructure. Summary of the Invention

[0007] To achieve the above objectives, the present invention adopts the following technical solution: One aspect of the present invention provides a noise control method for automotive pressure relief valves based on local resonant acoustic superstructures, comprising the following steps: Noise reduction targets are set based on the core noise reduction frequency band; the basic form of the superstructure is determined based on the available space around the pressure relief of the target vehicle; acoustic superstructure components are designed based on the main noise frequencies and the available space of the target vehicle; and a three-dimensional finite element model of the acoustic superstructure is constructed based on the basic form of the superstructure. The acoustic superstructure components are input into a three-dimensional finite element model for simulation analysis; the noise reduction effect is analyzed by comparing the simulation analysis results with the initial test results of the target vehicle, and the noise reduction results are obtained; based on the noise reduction results, the superstructure components are optimized until the noise reduction target is achieved.

[0008] In one alternative implementation, the process of constructing a three-dimensional finite element model of an acoustic superstructure based on the basic form of the superstructure includes the following steps: Using the defined basic form of the superstructure, the key feature dimensions of its resonant units are extracted as variable parameters. A parameterized three-dimensional geometric expression of each resonant unit is constructed through a geometry engine, forming an independent parameterized resonant unit model. Based on the determined core noise reduction frequency band, nonlinear constitutive relations of material parameters as a function of frequency are assigned to each component in the parametric resonant unit model. The nonlinear constitutive relations are then mapped to the entire parametric resonant unit model space to form a frequency-varying material property field covering the target frequency band. Based on the available space around the pressure relief valve of the target vehicle, the parameterized resonant element model carrying the frequency-varying material property field is embedded into the fluid domain representing the actual installation environment in a periodic arrangement. Periodic vibration constraints are applied to the boundary of the parameterized resonant element model to complete the integrated construction of the three-dimensional finite element model.

[0009] In one optional implementation, the process of applying periodic vibration constraints to the boundary of the parameterized resonant element model includes the following steps: Using the three-dimensional geometric boundary of the space around the pressure relief valve of the target vehicle, a continuous fluid region that can represent the space of the sound wave propagation medium is extracted inside the three-dimensional geometric boundary through a spatial scanning method, generating a physical boundary constrained fluid domain that is geometrically adapted to the actual vehicle installation environment. The generated physical boundary constrained fluid domain is used as the arrangement space, and the parameterized resonant unit model carrying the frequency-varying material property field is used as the basic unit. By solving the spatial pose sequence of the basic unit in the fluid domain that satisfies the maximum filling density and regular arrangement constraints, a superstructure array spatial configuration composed of multiple resonant units arranged in a regular manner is generated. Based on the generated superstructure array spatial configuration, nodal degree-of-freedom coupling relationships that ensure the continuity of displacement and stress are established at the contact interfaces between resonant units and between resonant units and the fluid domain, forming an interface degree-of-freedom coupling system that can simulate the interaction between vibration and sound waves. All components are integrated to complete the construction of the three-dimensional finite element model.

[0010] In one alternative implementation, the process of optimizing a superstructure component includes the following steps: Using the noise reduction results obtained from simulation analysis, the deviation data between the actual bandgap frequency range and the determined core noise reduction frequency band is extracted. Through the calculation of bandgap boundary frequency offset and the evaluation of bandgap depth attenuation, a bandgap characteristic offset vector describing the bandgap characteristic offset is formed. The bandgap characteristic offset vector is associated with the extracted key feature size parameters of the resonant unit. By calculating the sensitivity coefficient of each size parameter to the bandgap characteristics, the importance of each size parameter is sorted according to the magnitude of the sensitivity, and a parameter optimization priority sequence to guide the optimization order is generated. Guided by the parameter optimization priority sequence and constrained by the set noise reduction target, the key feature size parameters of the resonant unit are continuously adjusted through multiple rounds of iterative calculations until the bandgap characteristics completely cover the core noise reduction frequency band, and the optimized combination of superstructure part parameters that meets the noise reduction requirements is output.

[0011] In one optional implementation, the process of continuously adjusting the key feature size parameters of the resonant unit through multiple rounds of iterative calculation includes the following steps: The generated parameter optimization priority sequence is used to determine the adjustment order and initial adjustment direction of each key feature size parameter; combined with the frequency band coverage requirements in the set noise reduction target, the adjustment step size of each key feature size parameter is calculated to form a parameter adjustment decision vector to guide parameter adjustment. The parameter adjustment decision vector is applied to the key feature size parameters of the resonant unit, the three-dimensional finite element model is updated and the bandgap characteristics are simulated; the simulated bandgap characteristics are compared with the determined core noise reduction frequency band, the bandgap frequency coverage and attenuation satisfaction are calculated, and a quantitative bandgap coverage evaluation result is formed. Based on the bandgap coverage assessment results, check whether the bandgap characteristics fully cover the core noise reduction frequency band and meet the noise reduction target; if not, adjust the decision vector based on the assessment results and repeat to form the parameter adjustment decision vector that guides the parameter adjustment and form the quantified bandgap coverage assessment results; if satisfied, output the current key feature size parameters as the optimized superstructure part parameter combination.

[0012] In one alternative implementation, the process of generating a quantified bandgap coverage assessment result includes the following steps: The bandgap frequency range obtained from the simulation is compared point by point with the determined core noise reduction frequency band to identify the covered and uncovered areas of the core noise reduction frequency band within the bandgap frequency range, forming a bandgap coverage state matrix that describes the coverage status of each frequency point. Using the coverage area information in the bandgap coverage state matrix, the band coverage factor of the bandgap frequency range to the core noise reduction frequency band is calculated; combined with the bandgap depth attenuation data, the attenuation compliance rate within the coverage area is calculated, forming a set of coverage performance indicators that includes the band coverage factor and the attenuation compliance rate. The frequency band coverage factor and attenuation compliance rate in the coverage performance index group are weighted and fused according to the weight ratio in the set noise reduction target to obtain a comprehensive coverage index with a single value, which finally constitutes a quantitative bandgap coverage evaluation result.

[0013] In one optional implementation, the process of forming a set of coverage performance indicators including frequency band coverage factor and attenuation compliance rate includes the following steps: Analyze the distribution of coverage areas in the bandgap coverage state matrix, identify all continuous coverage frequency band segments, and statistically analyze the bandwidth values ​​of each segment and their position distribution in the core noise reduction frequency band to form an effective coverage frequency band set containing multiple independent coverage segments. The ratio of the total bandwidth of the effective coverage frequency band set to the total bandwidth of the core noise reduction frequency band is calculated as the frequency band coverage factor; at the same time, within the effective coverage frequency band set, the band gap depth attenuation data is compared with the threshold required by the noise reduction target, and the proportion of qualified frequency points is statistically analyzed to form a preliminary attenuation compliance rate; Based on the differences in importance of different sub-bands within the core noise reduction frequency band, the initial attenuation compliance rate is weighted and corrected, and the frequency band coverage factor and the weighted attenuation compliance rate are combined into a coverage performance index group with clear physical meaning.

[0014] In one optional implementation, the process of weighted correction of the initial attenuation compliance rate includes the following steps: Using the extracted noise peak frequency and its amplitude data, sound pressure level energy integration is performed on each sub-band within the core noise reduction frequency band. The proportion of noise energy in each sub-band to the total noise energy is calculated, forming a sub-band noise energy proportion vector describing the relative importance of the sub-bands. The sub-band noise energy proportion vector is normalized, and then the normalized weights are nonlinearly mapped and adjusted according to the priority requirements of the noise reduction target to form a sub-band importance weight vector for weighted calculation. The sub-band importance weight vector is multiplied by the compliance data of each sub-band in the preliminary attenuation compliance rate, and the sum is divided by the total weight to obtain the weighted average value that takes into account the differences in importance. This is the corrected weighted attenuation compliance rate.

[0015] In one alternative implementation, the process of forming a sub-band importance weight vector for weighted calculation includes the following steps: Based on the priority order of each sub-band determined by the noise reduction target, an enhancement coefficient positively correlated with the priority is assigned to each element in the normalized weight vector to form a sub-band enhancement coefficient vector for weight adjustment. Each element in the normalized weight vector is exponentially raised to the power of its corresponding enhancement coefficient. This power operation is used to nonlinearly amplify the weights of high-priority sub-bands, generating a nonlinearly amplified weight vector after nonlinear transformation. The summation and normalization of all elements in the nonlinear amplification weight vector are performed, and the sum of each element is consistent with the original normalized weight vector, thus obtaining a sub-band importance weight vector that maintains the relative importance relationship.

[0016] In one optional implementation, basic data of the target vehicle is acquired; multi-condition noise testing is performed based on the basic data of the target vehicle to determine the main noise frequency; the main radiation source of the pressure relief valve noise is located based on the main noise frequency, and the critical path of noise propagation inside the vehicle is analyzed; the main peak frequency of noise is extracted based on the main noise frequency, the main radiation source and the critical path to determine the core noise reduction frequency band.

[0017] This invention addresses the broadband noise problem in the mid-to-high frequency range of the pressure relief valve area in the rear compartment of automobiles. Through acoustic testing, the main noise frequency bands are determined, and an acoustic superstructure is designed as a noise reduction solution. This structure, while maintaining the original functional parameters of the pressure relief valve, directionally controls noise in the target frequency band, achieving frequency-selective sound energy attenuation. The acoustic superstructure mainly consists of resonant cavities, sound insulation panels, and a fixed frame, integrated or installed within the existing pressure relief valve structure. Through local structural resonance and multi-path interference mechanisms, this structure intervenes in the noise propagation path, thereby weakening the transmission of sound wave energy within a specific frequency range, and having a certain impact on the overall vehicle noise and vibration performance (NVH). A target vehicle requiring noise optimization is selected, ensuring it is in a curb weight condition, i.e., all working fluids (fuel, coolant, etc.) are filled, with no additional load; tire pressure is adjusted to the manufacturer's specified value, and the suspension system is in good condition. Real-vehicle testing is conducted at a standard test track, with two sound pressure monitoring points placed on either side of an impedance tube and a microphone probe installed inside the vehicle to represent the sensitive locations of the occupants. A multi-channel noise and vibration testing system was used to conduct in-vehicle dynamic noise tests on the target vehicle, acquire sound signal data under steady-state driving conditions, and perform spectrum analysis. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart illustrating the noise control method for automotive pressure relief valves based on local resonant acoustic superstructures provided by this invention. Figure 2 This is a schematic diagram showing the noise comparison at the measuring point provided by the present invention. Figure 3 This is a schematic diagram illustrating the comparison of in-vehicle noise provided by the present invention; Figure 4 A process diagram for determining the core noise reduction frequency band provided by the present invention; Figure 5 A flowchart illustrating the process of constructing a three-dimensional finite element model of an acoustic superstructure based on the fundamental form of the superstructure provided by this invention. Figure 6 Process diagrams for optimizing superstructure parts provided by this invention; Figure 7 A geometric diagram of an acoustic superstructure based on the quarter-wavelength tube principle provided for this invention; Figure 8 Internal structure diagram of the acoustic superstructure based on the quarter-wavelength tube principle provided for this invention; Figure 9 A geometric diagram of an acoustic superstructure based on the Helmholtz resonator principle provided for this invention; Figure 10 Internal structural diagram of the acoustic superstructure based on the Helmholtz resonator principle provided by this invention; Figure 11 A schematic diagram of the simulation model of acoustic superstructure transmission loss provided by the present invention; Figure reference numerals: 1. Acoustic superstructure based on quarter-wavelength tube; 2. Fixed frame; 11. Quarter-wavelength tube channel; 12. Sound insulation plate; 3. Acoustic superstructure based on Helmholtz resonator; 31. Helmholtz resonant cavity; 32. Sound insulation plate; 33. Square opening of Helmholtz resonator; 4. Schematic diagram of transmission loss simulation model; 41. Impedance tube; 42. Acoustic superstructure. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0020] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0021] like Figure 1 As shown, this embodiment provides a noise control method for automotive pressure relief valves based on a local resonant acoustic superstructure. This method specifically includes the following steps: Step S1: Obtain basic data of the target vehicle; conduct multi-condition noise tests based on the basic data of the target vehicle to determine the main noise frequency; locate the main radiation source of the pressure relief valve noise based on the main noise frequency and analyze the critical path of noise propagation inside the vehicle; extract the main peak frequency of noise based on the main noise frequency, main radiation source and critical path to determine the core noise reduction frequency band. Step S2: Set noise reduction targets based on the core noise reduction frequency band; determine the basic form of the superstructure based on the available space around the pressure relief of the target vehicle; design acoustic superstructure components based on the main noise frequencies and the available space of the target vehicle; construct a three-dimensional finite element model of the acoustic superstructure based on the basic form of the superstructure. Step S3: Input the acoustic superstructure components into the three-dimensional finite element model for simulation analysis; compare the simulation analysis results with the initial test results of the target vehicle to analyze the noise reduction effect and obtain the noise reduction analysis results; based on the noise reduction analysis results, optimize the superstructure components until the noise reduction target is achieved.

[0022] Preferably, this embodiment addresses the broadband noise problem in the mid-to-high frequency range of the vehicle's rear compartment pressure relief valve area. Acoustic testing identifies the main noise frequency band, and an acoustic superstructure is designed as a noise reduction solution based on this. This structure, while maintaining the original functional parameters of the pressure relief valve, provides directional control of noise in the target frequency band, achieving frequency-selective acoustic energy attenuation. The acoustic superstructure mainly consists of resonant cavities, sound insulation panels, and a fixed frame, integrated or installed within the existing pressure relief valve structure. Through local structural resonance and multi-path interference mechanisms, this structure intervenes in the noise propagation path, thereby weakening the transmission of sound wave energy within a specific frequency range, thus having a certain impact on the vehicle's overall noise and vibration performance (NVH). The target vehicle for noise optimization is selected, ensuring it is in a curb weight condition, i.e., all working fluids (fuel, coolant, etc.) are filled, there is no additional load, tire pressure is adjusted to the manufacturer's specified value, and the suspension system is in good condition. Real-vehicle testing was conducted at a standard testing ground. Two sound pressure monitoring points were positioned on either side of the impedance tube, and a microphone probe was installed inside the vehicle to represent the occupant's sensitive locations. A multi-channel noise and vibration testing system was used to perform dynamic noise testing inside the target vehicle, acquiring sound signal data under steady-state driving conditions and performing spectrum analysis. (For detailed principles, please refer to the appendix.) Figure 2 and appendix Figure 3 ).

[0023] like Figure 4 As shown, the process of determining the core noise reduction frequency band in step S1 of the embodiment of the present invention specifically includes the following steps: Step S11: Using the spatial distribution data of sound pressure from the main radiation sources, perform source contribution analysis on the main noise frequencies. This analysis calculates the correlation between each frequency component and the sound pressure distribution of the radiation sources, filters out the frequency components dominated by the pressure relief valve radiation source, eliminates interference from other noise sources, and obtains the set of source-dominant frequencies. Step S12: Combining the acoustic transmission characteristics of the critical path, by simulating the attenuation or enhancement effects of each frequency component on the critical path, the sound pressure level of the source dominant frequency set in the vehicle is corrected, and the effective frequency spectrum in the vehicle reflecting the actual in-vehicle noise impact is obtained. Step S13: Extract significant peak frequencies from the effective frequency spectrum inside the vehicle. Using an analysis method based on amplitude threshold and bandwidth clustering, merge adjacent peaks to form continuous frequency bands based on the amplitude and distribution range of the peak frequencies, and determine the core noise reduction frequency band.

[0024] Preferably, this embodiment utilizes correlation analysis between sound pressure spatial distribution data and frequency components to separate the noise generated by the pressure relief valve from the overall sound field, eliminating interference from other noise sources and forming a frequency set containing only the contribution of the pressure relief valve. Acoustic transmission simulation is performed on each frequency component along the critical path to correct for attenuation or enhancement effects within the vehicle, ensuring the obtained spectrum accurately reflects the actual distribution and intensity of noise inside the cabin. In the corrected effective frequency spectrum within the vehicle, significant peaks are extracted using amplitude thresholds and bandwidth clustering methods, and adjacent peaks are merged into continuous frequency bands, forming a core noise reduction frequency band that covers the main noise energy. This process ensures that the selected frequency band is both the noise source dominated by the pressure relief valve and the segment with the most significant actual noise impact within the vehicle, allowing for concentrated resources and precise suppression in subsequent noise reduction design, significantly reducing the overall noise level of the cabin.

[0025] Furthermore, the process of employing the analysis method based on amplitude threshold and bandwidth clustering in step S13 specifically includes the following steps: Step S131: Utilize the global statistical characteristics of the effective frequency spectrum inside the vehicle to obtain a dynamic threshold that varies with the spectral energy distribution; the dynamic threshold can adaptively identify peaks with significant acoustic energy in the core noise reduction frequency band, capture all potential candidate physical peaks, and form an initial set of candidate physical peaks. Step S132: Based on the principle of local resonance, it is believed that closely adjacent peaks may originate from multiple resonant modes of the same physical structure; based on the obtained set of candidate physical peaks, the proximity of any two peaks in frequency distribution and the similarity of their amplitude are obtained, and multiple peaks that simultaneously satisfy frequency proximity and amplitude similarity are grouped into the same group, each group representing a potential noise reduction mode group that needs to be coordinated and controlled. Step S133: Taking into account the engineering implementation constraints of the acoustic superstructure, bandwidth fusion is performed on the obtained potential noise reduction mode groups. The frequency distribution range of each group is analyzed, and groups with overlapping or very close frequency boundaries are merged to form a continuous frequency span covering all key modes. The frequency span is the determined core noise reduction frequency band with engineering feasibility.

[0026] Preferably, this embodiment utilizes global statistical characteristics to generate a dynamic threshold that varies with the spectral energy distribution. This automatically identifies and collects all candidate peaks with significant acoustic energy at different energy levels, ensuring that no potential noise sources are overlooked. Based on the principle of local resonance, peaks with similar frequencies and amplitudes are grouped into the same modal group, reflecting the multimodal resonance characteristics of the same structure or component, facilitating subsequent collaborative noise reduction control. Considering the constraints of acoustic superstructure implementation, bandwidth fusion is performed on the modal groups, merging groups with overlapping or very close frequency boundaries to form a continuous and achievable frequency span, providing a clear and practically operable core noise reduction frequency band. The above process ensures that the determined core noise reduction frequency band covers all key resonant modes and meets the bandwidth limitations of engineering implementation, allowing noise reduction measures to be concentrated on the most influential frequency band, significantly improving the noise reduction effect and reducing design complexity.

[0027] Furthermore, such as Figure 5 As shown, step S2, which involves constructing a three-dimensional finite element model of an acoustic superstructure based on its basic form, specifically includes the following steps: Step S21: Using the determined basic form of the superstructure, extract the key feature dimensions of its resonant units as variable parameters, and construct the parameterized three-dimensional geometric expression of each resonant unit through the geometry engine to form an independent parameterized resonant unit model. Step S22: Based on the determined core noise reduction frequency band, assign nonlinear constitutive relations of material parameters as a function of frequency to each component in the parameterized resonant unit model, and map the nonlinear constitutive relations to the entire parameterized resonant unit model space to form a frequency-varying material property field covering the target frequency band. Step S23: Based on the available space around the pressure relief valve of the target vehicle, the parameterized resonant element model carrying the frequency-varying material property field is embedded into the fluid domain representing the actual installation environment in a periodic arrangement. Periodic vibration constraints are applied to the boundary of the parameterized resonant element model to complete the integrated construction of the three-dimensional finite element model.

[0028] Preferably, in this embodiment, the key dimensions of the resonant unit are abstracted as variable parameters, and a parametric 3D model is generated using a geometry engine to achieve rapid and systematic adjustment of the unit's geometry. A nonlinear constitutive relation that varies with frequency is introduced within the model to form a material property field covering the core noise reduction frequency band, enabling the simulation to realistically reflect the material's dynamic acoustic response in the target frequency band. The parametric units with frequency-varying material properties are embedded in the fluid domain of the actual installation environment in a periodic arrangement, and periodic vibration constraints are applied to construct a 3D finite element model capable of simulating the realistic acoustic coupling around the vehicle's pressure relief valve. This embodiment allows for the simultaneous consideration of geometric adjustability, material frequency-varying characteristics, and actual installation constraints on the finite element platform, providing a high-fidelity, iterative simulation foundation for acoustic optimization and engineering implementation.

[0029] Furthermore, the process of forming an independent parameterized resonance unit model in step S21 specifically includes the following steps: Step S211: Using the determined basic form of the superstructure, analyze the geometric topology required to achieve local resonance, decompose the geometric topology into three functionally related primitives: mass block, elastic body, and connecting body, and obtain a set of topological primitives that completely define the geometric basis of the resonance unit. Step S212: Using the obtained set of topological primitives and the extracted key feature dimensions as input, establish the mutual driving relationship between the size parameters and the topological primitives, as well as between different primitives, in the geometry engine, forming a parameterized constraint relationship network in which all geometric elements are driven by the key feature size parameters and maintain relative position and functional association. Step S213: Drive the constructed parametric constraint relationship network, and solve the constraint relationship of the parametric constraint relationship network synchronously by assigning a set of key feature size values. Generate all topological primitives at once and automatically assemble them into a three-dimensional geometric entity with the correct functional form. The three-dimensional geometric entity is an independent parametric resonance unit model that can be directly called and modified.

[0030] Preferably, in this embodiment, the local resonance requirement of the resonant unit is transformed into three types of topological primitives: decomposable mass blocks, elastic bodies, and connecting bodies, forming a complete geometric framework. The driving relationship between key feature dimensions and each topological primitive is established in the geometry engine, constructing a unified parametric constraint network to ensure that the size, position, and functional association of all geometric elements are uniformly controlled. By solving the constraint network once and assigning dimensional values, a complete three-dimensional geometric entity is automatically generated and assembled, resulting in an independent parametric resonant unit model that can be directly called and subsequently modified, ensuring the functional correctness and adjustability of the geometric form.

[0031] Furthermore, the process of applying periodic vibration constraints to the boundary of the parameterized resonant element model in step S23 specifically includes the following steps: Step S231: Using the three-dimensional geometric boundary of the space around the pressure relief valve of the target vehicle, the continuous fluid region inside the boundary that can represent the space of the sound wave propagation medium is extracted by the spatial scanning method, and a physical boundary constrained fluid domain that is geometrically adapted to the actual vehicle installation environment is generated. Step S232: The generated physical boundary constrained fluid domain is used as the arrangement space, and the parameterized resonant unit model carrying the frequency-varying material property field is used as the basic unit. By solving the spatial pose sequence of the basic unit in the fluid domain that satisfies the maximum filling density and regular arrangement constraints, a superstructure array spatial configuration composed of multiple resonant units arranged according to a specific rule is generated. The detailed process of generating the spatial configuration of the superstructure array by solving the spatial pose sequence of basic units in the fluid domain to satisfy the constraints of maximum filling density and regular arrangement is as follows: First, the parameterized resonant unit model is abstracted into a set of independently controllable six-degree-of-freedom spatial pose parameters; then, taking the geometric space of the fluid domain constrained by the physical boundary as the optimization domain, an arrangement optimization program is established with the goal of minimizing the contact potential energy between units and the constraint of no interference between units and the fluid domain boundary; finally, by iteratively solving this optimization, the pose parameter sequence that makes all resonant units achieve the most compact and regular arrangement in a finite space is output, thereby determining the specific spatial configuration of the superstructure array. Step S233: Based on the generated superstructure array spatial configuration, establish nodal degree-of-freedom coupling relationships to ensure the continuity of displacement and stress at the contact interfaces between resonant units and between resonant units and the fluid domain, forming an interface degree-of-freedom coupling system that can simulate the interaction between vibration and sound waves. Integrate all components to complete the construction of the three-dimensional finite element model.

[0032] Preferably, in this embodiment, a fluid domain matching the actual installation environment is extracted within the space surrounding the vehicle's pressure relief valve, forming a physical boundary constraint capable of realistically reproducing the sound wave propagation path. Within the fluid domain, the spatial pose of the parameterized resonant elements is solved using maximum filling density and regular arrangement constraints, generating a superstructure array configuration that conforms to spatial limitations, achieving an efficient and feasible layout of the resonant elements. Continuous nodal coupling relationships of displacement and stress are established between the resonant elements and at the contact interfaces between the resonant elements and the fluid domain, constructing a complete interface degree-of-freedom coupling system. This allows the finite element model to synchronously simulate the interaction between vibration and sound waves, providing high-fidelity acoustic response prediction.

[0033] Furthermore, the process of forming an interface degree-of-freedom coupled system capable of simulating the interaction between vibration and sound waves in step S233 specifically includes the following steps: Step S2331: Using the contact surface information between resonant units and between resonant units and fluid domain in the spatial configuration of the superstructure array, identify all interface regions where motion coordination relationships need to be established, and form a set of interface motion coordination relationships including interface position, normal and tangential motion transmission relationships. Step S2332: Based on the set of interface motion coordination relationships, establish displacement continuity constraints and stress balance constraints respectively, and transform the displacement continuity constraints and stress balance constraints into mathematical relationships between nodal degrees of freedom to form a coupled constraint system describing the rules of physical quantity transmission at the interface. The process of establishing a coupled constraint system based on the set of interface motion coordination relationships is as follows: Based on the identified set of interface motion coordination relationships, a continuous coordination condition for the displacement field is established at the resonant unit-fluid contact interface, and a stress field equilibrium coordination condition is established at the resonant unit-unit contact interface; the physical coordination conditions are transformed into displacement constraint equations and stress equilibrium equations for the corresponding nodes in the normal and tangential degrees of freedom; finally, the mathematical equations are organized into a unified coupled constraint system to fully describe the energy transfer mechanism at the interface. Step S2333: Integrate the coupled constraint system into the overall system matrix according to the finite element discretization format, and embed the interface coordination conditions into the mathematical form that the system solver can recognize through constraint processing technology, thereby completing the construction of the interface degree of freedom coupled system.

[0034] Preferably, this embodiment fully identifies and defines the motion transmission characteristics between resonant elements and their contact surfaces with the fluid domain, forming a unified set of interface motion coordination relationships. The physical constraints of displacement continuity and stress balance are transformed into mathematical coupling relationships of nodal degrees of freedom, constructing a constraint system describing the transmission of physical quantities at the interface. This coupled constraint system is embedded into the overall system matrix in a finite element discretization form, ensuring that the solver can simultaneously handle the interaction between structural vibration and sound field propagation, achieving high-fidelity, unified vibration... Acoustic wave coupling simulation.

[0035] Furthermore, such as Figure 6 As shown, the process of optimizing the superstructure part in step S3 specifically includes the following steps: Step S31: Using the analysis and noise reduction results obtained from simulation analysis, extract the deviation data between the actual bandgap frequency range and the determined core noise reduction frequency band. Through the calculation of bandgap boundary frequency offset and the evaluation of bandgap depth attenuation, form a bandgap characteristic offset vector describing the bandgap characteristic offset. Step S32: Associate the bandgap characteristic offset vector with the extracted key feature size parameters of the resonant unit, calculate the sensitivity coefficient of each size parameter to the bandgap characteristics, sort the size parameters according to the magnitude of sensitivity, and generate a parameter optimization priority sequence to guide the optimization order; The process of calculating the sensitivity coefficients of the influence of each size parameter on the bandgap characteristics is as follows: a small normalized perturbation is applied to each key characteristic size parameter of the resonant element, and the bandgap boundary frequency and bandgap depth under the normalized perturbation are recalculated using the finite element model; the ratio of the obtained bandgap characteristic change to the initial perturbation is used as the sensitivity coefficient of the key characteristic size parameter; by comparing the bandgap characteristic response under all parameter perturbations, the degree of influence of each size parameter on the bandgap characteristics is quantified. Step S33: Guided by the parameter optimization priority sequence and with the set noise reduction target as the constraint, the key feature size parameters of the resonant unit are continuously adjusted through multiple rounds of iterative calculations until the bandgap characteristics completely cover the core noise reduction frequency band, and the optimized superstructure part parameter combination that meets the noise reduction requirements is output.

[0036] Preferably, in this embodiment, the noise reduction results obtained from simulation are compared with the target core frequency band to quantify the bandgap frequency shift and attenuation depth, forming a vector describing the bandgap characteristic shift and providing a clear error index for optimization. Based on the bandgap characteristic shift vector, the sensitivity coefficients of the dimensional parameters are calculated, and the importance of key feature dimensions is ranked to generate a priority sequence for parameter optimization, ensuring that the optimization process focuses on the geometric factors that have the greatest impact on the bandgap. According to the optimization priority, the key dimensional parameters are iteratively adjusted under constraints, so that the bandgap characteristics gradually approach and completely cover the core noise reduction frequency band, ultimately obtaining a combination of superstructure component parameters that meets the noise reduction requirements, improving the overall noise reduction performance and ensuring the feasibility of the design.

[0037] Furthermore, the process of continuously adjusting the key feature size parameters of the resonant unit through multiple rounds of iterative calculation in step S33 specifically includes the following steps: Step S331: Utilize the generated parameter optimization priority sequence to determine the adjustment order and initial adjustment direction of each key feature size parameter; combine the frequency band coverage requirements in the set noise reduction target to calculate the adjustment step size of each key feature size parameter, forming a parameter adjustment decision vector to guide parameter adjustment; Step S332: Apply the parameter adjustment decision vector to the key feature size parameters of the resonant unit, update the three-dimensional finite element model and perform bandgap characteristic simulation; compare the simulated bandgap characteristics with the determined core noise reduction frequency band, calculate the bandgap frequency coverage and attenuation satisfaction, and form a quantitative bandgap coverage evaluation result. Step S333: Based on the bandgap coverage evaluation results, check whether the bandgap characteristics fully cover the core noise reduction frequency band and meet the noise reduction target; if not, adjust the parameter adjustment decision vector based on the evaluation results and repeat to form the parameter adjustment decision vector that guides the parameter adjustment and form the quantified bandgap coverage evaluation results; if satisfied, output the current key feature size parameters as the optimized superstructure part parameter combination.

[0038] Preferably, this embodiment determines the adjustment order, direction, and step size of dimensional parameters based on an optimized priority sequence, forming a systematic parameter adjustment decision vector to ensure that each iteration focuses on the most critical geometric factors. The decision vector is applied to a three-dimensional finite element model and bandgap simulation is performed to evaluate bandgap frequency coverage and attenuation satisfaction in real time, providing a quantitative evaluation of bandgap coverage. The parameter decision vector is dynamically corrected based on the evaluation results, iterating cyclically until the bandgap characteristics fully cover the core noise reduction frequency band and meet the attenuation requirements, ultimately outputting a superstructure component parameter combination that meets the noise reduction target.

[0039] Furthermore, the process of generating a quantified bandgap coverage assessment result in step S332 specifically includes the following steps: Step S3321: Compare the bandgap frequency range obtained from the simulation with the determined core noise reduction frequency band point by point, identify the covered and uncovered areas of the core noise reduction frequency band within the bandgap frequency range, and form a bandgap coverage state matrix describing the coverage state of each frequency point. Step S3322: Calculate the band coverage factor of the band gap frequency range for the core noise reduction frequency band using the coverage area information in the band gap coverage state matrix; combine the band gap depth attenuation data to calculate the attenuation compliance rate within the coverage area, forming a coverage performance index group that includes the band coverage factor and the attenuation compliance rate. Step S3323: The frequency band coverage factor and attenuation compliance rate in the coverage performance index group are weighted and fused according to the weight ratio in the set noise reduction target to obtain a comprehensive coverage index with a single value, which finally constitutes a quantitative bandgap coverage evaluation result.

[0040] Preferably, in this embodiment, the simulated bandgap frequency range is compared point-by-point with the target core noise reduction frequency band to generate a coverage state matrix, clarifying the coverage or absence status of each frequency point. Based on the coverage state matrix, the band coverage factor is calculated, and combined with bandgap depth attenuation data, the attenuation compliance rate of the covered area is obtained, forming a dual performance index reflecting both coverage range and attenuation effect. The band coverage factor and attenuation compliance rate are weighted and fused according to the weights set by the noise reduction target to obtain a single comprehensive coverage index, achieving a quantitative evaluation of the bandgap characteristics relative to the core noise reduction frequency band.

[0041] Furthermore, the process of forming a set of coverage performance indicators including frequency band coverage factor and attenuation compliance rate in step S3322 specifically includes the following steps: Step S33221: Analyze the distribution of coverage areas in the bandgap coverage state matrix, identify all continuous coverage frequency band segments, and statistically analyze the bandwidth values ​​of each segment and their position distribution in the core noise reduction frequency band to form an effective coverage frequency band set containing multiple independent coverage segments. Step S33222: Calculate the ratio of the total bandwidth of the effective coverage frequency band set to the total bandwidth of the core noise reduction frequency band as the frequency band coverage factor; at the same time, within the effective coverage frequency band set, compare the band gap depth attenuation data with the threshold required by the noise reduction target, and statistically analyze the proportion of qualified frequency points to form a preliminary attenuation compliance rate. Step S33223: Based on the differences in importance of different sub-bands within the core noise reduction frequency band, the initial attenuation compliance rate is weighted and corrected, and the frequency band coverage factor and the weighted attenuation compliance rate are combined into a coverage performance index group with clear physical meaning.

[0042] Preferably, in this embodiment, all continuous effective coverage frequency bands are extracted from the coverage state matrix, and their bandwidth and position in the core noise reduction frequency band are statistically analyzed to form a complete set of effective coverage frequency bands. The proportion of the total bandwidth of the effective coverage frequency band set to the total bandwidth of the core noise reduction frequency band is calculated to obtain the frequency band coverage factor. Within the frequency band, the band gap attenuation degree is compared with the target threshold, and the proportion of frequency points that meet the threshold is statistically analyzed to form a preliminary attenuation compliance rate. The attenuation compliance rate is weighted and corrected according to the importance of each sub-frequency band of the core frequency band, and the weighted attenuation compliance rate is combined with the frequency band coverage factor to obtain a set of coverage performance indicators with clear physical meaning, thereby achieving a comprehensive quantitative evaluation of the band gap coverage range and attenuation effect.

[0043] Furthermore, the process of weighted correction of the initial attenuation compliance rate in step S33223 specifically includes the following steps: Step S332231: Using the extracted noise peak frequency and its amplitude data, perform sound pressure level energy integration on each sub-band within the core noise reduction frequency band, calculate the proportion of noise energy in each sub-band to the total noise energy, and form a sub-band noise energy proportion vector describing the relative importance of the sub-bands; Step S332232: Normalize the sub-band noise energy proportion vector, and then adjust the normalized weights by nonlinear mapping according to the priority requirements of the noise reduction target to form a sub-band importance weight vector for weighted calculation. Step S332233: Perform a dot product operation between the sub-band importance weight vector and the compliance data of each sub-band in the preliminary attenuation compliance rate, sum the results and divide by the total weight to obtain the weighted average value that takes into account the differences in importance, which is the corrected weighted attenuation compliance rate.

[0044] Preferably, in this embodiment, based on the noise peak and its amplitude, energy integration is performed on each sub-band of the core noise reduction frequency band to obtain a sub-band noise energy proportion vector, quantifying the relative importance of each sub-band. The noise energy proportion vector is normalized and nonlinearly mapped according to the priority of the noise reduction target to generate a sub-band importance weight vector reflecting actual needs. The sub-band importance weight vector is multiplied by the sub-band compliance data of the initial attenuation compliance rate and normalized to obtain a weighted average corrected attenuation compliance rate, realizing a comprehensive consideration of the differences in importance of different sub-bands.

[0045] Furthermore, the process of forming the sub-band importance weight vector for weighted calculation in step S332232 specifically includes the following steps: Step S3322321: Based on the priority order of each sub-band determined by the noise reduction target, assign an enhancement coefficient positively correlated with the priority to each element in the normalized weight vector to form a sub-band enhancement coefficient vector for weight adjustment; Step S3322322: Each element in the normalized weight vector is exponentially operated on with its corresponding enhancement coefficient as the exponent. The exponentiation operation is used to achieve nonlinear amplification of the weights of high-priority sub-bands, generating a nonlinear amplified weight vector after nonlinear transformation. Step S3322323: Summate and normalize all elements in the nonlinear amplification weight vector. The sum of each element is consistent with the original normalized weight vector, thus obtaining a sub-band importance weight vector that maintains the relative importance relationship.

[0046] Preferably, in this embodiment, an enhancement coefficient positively correlated with the priority of each normalized weight is assigned according to the sub-band priority of the noise reduction target, constructing an enhancement coefficient vector for weight adjustment. The normalized weights are exponentially raised using the enhancement coefficients as exponents to achieve nonlinear amplification of the weights of high-priority sub-bands, resulting in a nonlinear amplified weight vector. This nonlinear amplified weight vector is then normalized so that its sum returns to the level of the original normalized weights, maintaining the relative importance of each sub-band, thus forming the final sub-band importance weight vector.

[0047] like Figures 7-11As shown, this embodiment also provides a noise control system for a car pressure relief valve based on a local resonant acoustic superstructure. This noise control system for a car pressure relief valve based on a local resonant acoustic superstructure is applied to the above-mentioned noise control method for a car pressure relief valve based on a local resonant acoustic superstructure. The noise control system for a car pressure relief valve based on a local resonant acoustic superstructure includes: an acoustic superstructure 1 based on a quarter-wavelength tube, a fixed frame 2, a quarter-wavelength tube channel 11, a sound insulation plate 12, an acoustic superstructure 3 based on a Helmholtz resonator, a Helmholtz resonant cavity 31, a sound insulation plate 32, a square opening 33 of a Helmholtz resonator, a transmission loss simulation model 4, an impedance tube 41, and an acoustic superstructure 42. Among them, such as Figure 7 As shown, the fixed frame 2 is connected below the acoustic superstructure 1 based on a quarter-wavelength tube; as Figure 8 As shown, the acoustic superstructure 1 based on a quarter-wavelength tube includes a quarter-wavelength tube channel 11 and a sound insulation plate 12; as Figure 9 As shown, the fixed frame 2 is connected to the acoustic superstructure 3 based on the Helmholtz resonator; as Figure 10 As shown, the acoustic superstructure 3 based on the Helmholtz resonator includes a Helmholtz resonant cavity 31, a sound insulation plate 32, and a square opening 33 for the Helmholtz resonator; wherein, the sound insulation plate 32 has the square opening 33 for the Helmholtz resonator, and the Helmholtz resonant cavity 31 is provided within the sound insulation plate 32; as shown... Figure 11 As shown, the transmission loss simulation model 4 has an impedance tube 41 on the outside and an acoustic superstructure 42 inside. Preferably, the acoustic superstructure 1 consists of four basic units arranged in a 2×2 grid pattern. Each basic unit consists of multiple quarter-wavelength tubes as local resonant units. Each unit has five parallel rectangular quarter-wavelength tube channels 11 arranged longitudinally. Each channel is further divided into two cavity structures of unequal length by a sound insulation plate 12. One end of each cavity is closed and the other end is open. Due to the difference in length of each cavity, they can correspond to different resonant frequencies, achieving a frequency response distribution within a certain range, which is used to absorb or attenuate sound waves of specific frequencies in the pressure relief valve channel. A fixed frame 2 is provided at one end of the structure for connection and installation with the original pressure relief valve system. The working mechanism of the quarter-wavelength tube 11 is to achieve noise reduction by using the reflection and interference of sound waves in a closed pipe. When an external sound wave enters a pipe that is closed at one end and open at the other, the sound wave is reflected after propagating to the closed end in the pipe. Since the closed end is a pressure vessel and the open end is a pressure joint, when the length of the pipe is equal to one-quarter of the wavelength of the target sound wave, the sound wave that propagates back and forth is out of phase with the incident wave, forming destructive interference, which effectively cancels out the sound energy of that frequency, thereby achieving the noise reduction effect. The acoustic superstructure 3 has multiple rectangular slot cavities 31 carved out inside a rectangular frame and separated by sound insulation panels 32. These slots, as part of the resonant cavity, connect to small square holes 33 on the inner side of the frame, forming channels with specific opening areas. This constitutes a typical Helmholtz resonant unit. By controlling the opening area and cavity volume of the Helmholtz resonant unit within the rectangular frame, different resonant frequencies can be adjusted, thereby achieving coverage of the target frequency range in the automotive pressure relief valve area. A fixed frame 2 is provided at one end of the structure for connection and installation with the existing pressure relief valve system. When external noise enters the structure through the pressure relief valve, the air column in the neck region of each resonator unit vibrates reciprocally after receiving acoustic excitation. This vibrating part can be equivalent to a "mass block." Simultaneously, the air inside the cavity is compressed and expanded during vibration, exhibiting a spring-like effect. The entire system constitutes a typical acoustic mass-spring oscillator structure. When the frequency of the external sound wave approaches the structure's natural frequency, the system resonates, causing acoustic energy to accumulate and be consumed within the structure, primarily through air viscosity and thermal conduction, thus reducing the energy of the sound wave at that frequency. This mechanism causes attenuation of specific frequency sound waves entering the cavity during propagation, reducing transmitted or reflected sound pressure and facilitating acoustic energy control within the target frequency range. After the initial structural construction of the acoustic superstructure is completed, to evaluate its sound absorption capacity in the low-frequency band and further adjust key geometric parameters to align with the design frequency range, it is necessary to simulate and optimize the structural performance using the acoustic finite element method. In a preferred embodiment of this invention, a three-dimensional finite element model of the acoustic superstructure is constructed using the COMSOL Multiphysics simulation platform. To effectively simulate the acoustic response of the structure under standard test conditions, a complete superstructure and impedance tube combination system was constructed as the simulation domain. The three-dimensional finite element model of the acoustic superstructure consists of two parts: an impedance tube 41 and an acoustic superstructure 42. The impedance tube region is modeled using a pressure acoustic domain to describe the propagation behavior of sound waves in the mid-to-low frequency range as plane waves. For regions within the structure with multiple narrow slits and zigzag paths, a thermoviscous acoustic domain is used to capture heat loss and viscous dissipation phenomena at the subwavelength scale. The sound source is set as a background pressure field to simulate plane waves propagating along the impedance tube axis; the tube wall is set as a rigid boundary to eliminate the influence of wall deformation on the sound field, and the end is designed as a non-reflective condition to avoid interference caused by multiple sound wave reflections.

[0048] In summary, to facilitate the analysis of the acoustic characteristics of the embodiments described, this embodiment constructs a theoretical model of the acoustic superstructure based on the transfer matrix method. Each local resonant unit in this embodiment has independent geometric dimensions, including the wavelength tube length. cavity volume and the cross-sectional area of ​​the pipe or opening ,in These represent different wavelength tubes or Helmholtz resonators; The expressions for the complex wave number and complex impedance of the sound wave in different parts of the system are:

[0049]

[0050] in This represents the equivalent radius of the pipe structure. In this example, the pipe has a square cross-section, hence its equivalent radius is... , Represents angular frequency. Represents the imaginary unit. Indicates air density, Represents the speed of sound in air and the thickness of the boundary layer. ,in The viscosity coefficient of air. Indicates the air heat capacity ratio. =0.702 represents the Prandtl number under standard voltage; The transfer matrix expression for sound wave propagation in a single wavelength tube is:

[0051] The Helmholtz resonator can be considered as two pipes connected in series, and the transfer matrix of sound waves propagating inside it can be expressed as:

[0052] in The transfer matrix for sound wave propagation in the neck of a Helmholtz resonator. The transfer matrix is ​​the propagation matrix of sound waves in the Helmholtz resonator cavity. The correction matrix resulting from the end-point correction length caused by the abrupt change in the intermediate cross-section of the Helmholtz resonator is expressed as follows:

[0053] in For wave vector, This is the correction length caused by cross-sectional discontinuity. The expression is:

[0054] Since the volume velocity at the end of the system is zero, the equivalent impedance of this local resonant element can be derived as follows:

[0055] The transfer matrix of sound waves with local resonant units as side branches can be expressed as:

[0056] The transfer matrix of sound wave propagation between different local resonant units can be expressed as:

[0057] The transfer matrix of the entire system can be expressed as:

[0058] The acoustic transmission loss of the acoustic superstructure can then be expressed as:

[0059] The above formula can also provide some theoretical guidance for designing acoustic superstructures whose resonant frequency covers the target frequency.

[0060] Acoustic metastructures, due to their small internal microstructure size, will induce significant boundary layer effects during sound wave propagation, including heat dissipation and viscous loss. These factors will directly affect the location of their sound absorption peak, bandwidth range, and absorption efficiency. Therefore, during the modeling process, thermal-viscous boundary conditions need to be introduced inside the structure to achieve high-precision simulation of the actual sound field response. The simulation model has two sound pressure monitoring points on both sides of the impedance tube to collect sound pressure data of the incident and transmitted waves. By comparing the pressure amplitudes at the two points, the transmission loss of the sound wave can be calculated, and the sound absorption characteristics of the structure at different frequencies can be evaluated accordingly. During the simulation, multiple sets of variables are scanned around the length and cross-sectional geometric parameters of the wavelength tube. By analyzing the trend of transmission loss with frequency, it is determined whether the position of the resonance peak meets the requirements of the design frequency band, and the relevant structural parameters are adjusted accordingly. The optimized metamaterial structure is formed by 3D printing or other methods and integrated with the pressure relief valve housing. It is then installed in the target vehicle for testing. During the installation process, it is first necessary to ensure that the metastructure does not mechanically interfere with the original structure inside the vehicle. Secondly, a rigid buckle fixing method is used to ensure that the structure has good mechanical stability during vehicle operation, effectively avoiding the generation of secondary noise or the occurrence of structural loosening and falling off. After the acoustic superstructure was installed, the modified vehicle under the same operating conditions as the previous test was subjected to another noise test in the pressure relief valve area. The test results show that installing the acoustic superstructure can effectively improve the noise at the target frequency. To ensure that the acoustic superstructure has the required wideband noise reduction capability and stability for mass production in the automotive pressure relief valve area, its structural design can be optimized during the product finalization stage.

[0061] It should be noted that, to address the potential interaction between the airflow path and the sound propagation path, the airflow channels within the acoustic superstructure can be adjusted. By rearranging the positions of the ventilation holes, optimizing the cross-sectional structure of the air ducts, and adjusting the flow direction, the airflow distribution within the structure can be made more uniform, reducing potential high-velocity areas in local regions. This reduces eddy current disturbances caused by sudden changes in flow velocity and the potential risk of structural vibration. This adjustment helps maintain the acoustic response stability of the structure under ventilation conditions without interfering with the pressure relief function, thus maintaining the basic performance requirements of the vehicle's ventilation and defogging systems. In terms of structural rigidity, the supporting structure of the internal sound insulation panel can be reinforced to further control the sound transmission path in the mid-to-high frequency band. By adjusting material parameters, optimizing the arrangement of ribs, and carrying out local reinforcement, the acoustic structure's resistance to deformation can be improved, reducing secondary resonance phenomena caused by excited vibration of the panels. This helps to suppress sound energy leakage, stabilize acoustic performance, and exhibit higher consistency, especially under specific operating conditions (such as high-speed driving or sudden changes in wind pressure).

[0062] This invention features a targeted design for the target frequency band, comprehensively utilizing numerical simulation, single-unit structural prototype testing, and measured noise data under actual vehicle road conditions to verify its noise reduction performance and adaptability to vehicle platforms. Within the target frequency range, the acoustic superstructure can, to a certain extent, reduce mid-to-high frequency noise transmitted into the passenger compartment via the pressure relief channel. Without affecting the pressure relief function, the structure maintains the original vehicle's ventilation efficiency at the baseline level, meeting the basic requirements for vehicle ventilation and air exchange.

[0063] In one specific embodiment, the structure adopts a relatively compact layout, and its size and interface can be adjusted according to the space available on the vehicle platform, exhibiting a certain degree of modularity and platform compatibility. This structure can be adapted to the space constraints of actual vehicle models, enabling integrated applications across different platforms.

[0064] Compared with the existing method of using a pressure relief valve with a soundproof cover and sound-absorbing materials for noise reduction, this embodiment shows certain differences in terms of noise reduction frequency bandwidth, structural integration method, environmental adaptability and structural stability, and is suitable for scenarios with specific requirements for mid-to-high frequency noise control.

[0065] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or equivalent to the scope of this invention are included in this invention.

[0066] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0067] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0068] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for noise control of a vehicle pressure relief valve based on a local resonance acoustic superstructure, characterized by, The method comprises the following steps: setting a noise reduction target based on a core noise reduction frequency band; determining a basic form of the superstructure for a space where the target vehicle can be arranged around a pressure relief valve; designing an acoustic superstructure component based on a main noise frequency and the space where the target vehicle can be arranged; constructing a three-dimensional finite element model of the acoustic superstructure based on the basic form of the superstructure; inputting the acoustic superstructure component into the three-dimensional finite element model for simulation analysis; comparing the simulation analysis result with an initial test result of the target vehicle, analyzing a noise reduction effect, and obtaining an analysis noise reduction result; optimizing the superstructure component based on the analysis noise reduction result until the noise reduction target is reached.

2. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 1, wherein, The process of constructing the three-dimensional finite element model of the acoustic superstructure based on the basic form of the superstructure comprises the following steps: extracting key feature sizes of a resonance unit of the determined basic form of the superstructure as variable parameters, constructing a parameterized three-dimensional geometric expression of each resonance unit through a geometry engine, and forming an independent parameterized resonance unit model; according to the determined core noise reduction frequency band, assigning a nonlinear constitutive relation with frequency-varying material parameters to each component in the parameterized resonance unit model, mapping the nonlinear constitutive relation to the entire parameterized resonance unit model space, and forming a frequency-varying material attribute field covering the target frequency band; according to the determined space where the target vehicle can be arranged around the pressure relief valve, embedding the parameterized resonance unit model carrying the frequency-varying material attribute field into a fluid domain representing an actual installation environment in a periodic arrangement manner, and applying a periodic vibration constraint condition to the boundary of the parameterized resonance unit model to complete the integrated construction of the three-dimensional finite element model.

3. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 2, wherein, The process of applying the periodic vibration constraint condition to the boundary of the parameterized resonance unit model comprises the following steps: using the three-dimensional geometric boundary of the determined space where the target vehicle can be arranged around the pressure relief valve, extracting a continuous fluid region inside the three-dimensional geometric boundary which can represent the space of a sound wave propagation medium through a space scanning method, and generating a physical boundary constraint fluid domain which is geometrically adapted to the actual vehicle installation environment; taking the generated physical boundary constraint fluid domain as the arrangement space and the parameterized resonance unit model carrying the frequency-varying material attribute field as the basic unit, generating a superstructure array space configuration composed of multiple resonance units arranged in a regular manner by solving the space pose sequence of the basic unit satisfying the maximum packing density and the regular arrangement constraint in the fluid domain; according to the generated superstructure array space configuration, establishing a node degree of freedom coupling relationship between the resonance units and the contact interfaces between the resonance units and the fluid domain to ensure the continuity of displacement and stress, forming an interface degree of freedom coupling system which can simulate the interaction of vibration and sound waves, integrating all components, and completing the construction of the three-dimensional finite element model.

4. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 1, wherein, The process of optimizing the superstructure component comprises the following steps: extracting deviation data between an actual bandgap frequency range and the determined core noise reduction frequency band from the analysis noise reduction result obtained through simulation analysis, and forming a bandgap characteristic offset vector describing the offset of the bandgap characteristics by calculating the bandgap boundary frequency offset and evaluating the bandgap depth attenuation degree; The band gap characteristic offset vector is associated with the extracted key feature size parameters of the resonant unit, the sensitivity coefficients of the size parameters to the influence of the band gap characteristics are calculated, the importance of the size parameters is sorted according to the sensitivity, and a parameter optimization priority sequence guiding the optimization order is generated; With the parameter optimization priority sequence as a guide, the set noise reduction target as a constraint condition, the key feature size parameters of the resonant unit are continuously adjusted through multiple rounds of iterative calculations until the band gap characteristics completely cover the core noise reduction frequency band, and the optimized superstructure part parameter combination meeting the noise reduction requirements is output.

5. The local-resonance-acoustics- superstructure-based noise control method for a vehicle pressure relief valve of claim 4, wherein, The process of continuously adjusting the key feature size parameters of the resonant unit through multiple rounds of iterative calculations includes the following steps: Using the generated parameter optimization priority sequence, the adjustment order and initial adjustment direction of each key feature size parameter are determined; combining the frequency band coverage requirement in the set noise reduction target, the adjustment step of each key feature size parameter is calculated to form a parameter adjustment decision vector guiding parameter adjustment; The parameter adjustment decision vector is applied to the key feature size parameters of the resonant unit, the three-dimensional finite element model is updated and the band gap characteristic simulation is performed; the band gap characteristics obtained by simulation are compared with the determined core noise reduction frequency band, the band gap frequency coverage rate and attenuation satisfaction degree are calculated to form a quantitative band gap coverage evaluation result; According to the band gap coverage evaluation result, it is checked whether the band gap characteristics completely cover the core noise reduction frequency band and meet the noise reduction target; if not, the parameter adjustment decision vector is corrected based on the evaluation result and the parameter adjustment decision vector guiding parameter adjustment is repeatedly formed and the quantitative band gap coverage evaluation result is formed; if yes, the current key feature size parameters are output as the optimized superstructure part parameter combination.

6. The local-resonance-acoustics- superstructure-based noise control method for a vehicle pressure relief valve of claim 5, wherein, The process of forming a quantitative band gap coverage evaluation result includes the following steps: The band gap frequency range obtained by simulation is compared with the determined core noise reduction frequency band point by point, the covered area and the uncovered area of the core noise reduction frequency band in the band gap frequency range are identified, and a band gap coverage state matrix describing the coverage state of each frequency point is formed; Using the coverage area information in the band gap coverage state matrix, the frequency band coverage factor of the band gap frequency range to the core noise reduction frequency band is calculated; combining the band gap depth attenuation degree data, the attenuation standard rate in the covered area is calculated to form a coverage performance index group containing the frequency band coverage factor and the attenuation standard rate; The frequency band coverage factor and the attenuation standard rate in the coverage performance index group are weighted and fused according to the weight proportion in the set noise reduction target to obtain a single-valued comprehensive coverage index, which finally constitutes the quantitative band gap coverage evaluation result.

7. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 6, wherein, The process of forming a coverage performance index group containing a frequency band coverage factor and an attenuation standard rate includes the following steps: Analyze the coverage area distribution in the band gap coverage state matrix, identify all continuous coverage frequency band segments, count the bandwidth values of each segment and their position distribution in the core noise reduction frequency band, and form an effective coverage frequency band set containing multiple independent coverage segments; A ratio of a total bandwidth of the effective coverage frequency band set and a total bandwidth of the core noise reduction frequency band is calculated as a frequency band coverage factor; meanwhile, within the range of the effective coverage frequency band set, a band gap depth attenuation degree data is compared with a threshold value of a noise reduction target requirement, a proportion of frequency points meeting the requirement is counted to form a preliminary attenuation compliance rate; According to the importance difference of different sub-frequency bands in the core noise reduction frequency band, the preliminary attenuation compliance rate is weighted and corrected, and the frequency band coverage factor and the weighted attenuation compliance rate are combined into a coverage efficiency index group with clear physical meaning.

8. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 7, wherein, The process of weighting and correcting the preliminary attenuation compliance rate includes the following steps: Using the extracted noise main peak frequency and its amplitude data, the sound pressure level energy of each sub-frequency band in the core noise reduction frequency band is integrated, the proportion of noise energy of each sub-frequency band in the total noise energy is calculated to form a sub-frequency band noise energy proportion vector describing the relative importance of the sub-frequency band; The sub-frequency band noise energy proportion vector is normalized, and then the normalized weight is adjusted by non-linear mapping according to the priority requirement of the noise reduction target to form a sub-frequency band importance weight vector for weighted calculation; The sub-frequency band importance weight vector and the compliance data of each sub-frequency band in the preliminary attenuation compliance rate are multiplied, and then the sum is divided by the total weight to obtain a weighted average value considering the importance difference, which is the corrected weighted attenuation compliance rate.

9. The local-resonance-acoustic-structure-based noise control method for a vehicle pressure relief valve of claim 8, wherein, The process of forming the sub-frequency band importance weight vector for weighted calculation includes the following steps: According to the priority order of each sub-frequency band determined by the noise reduction target, each element in the normalized weight vector is assigned a reinforcement coefficient positively related to the priority to form a sub-frequency band reinforcement coefficient vector for weight adjustment; Each element in the normalized weight vector is raised to the power of its corresponding reinforcement coefficient to realize non-linear amplification of the weight of high-priority sub-frequency bands through power operation, generating a non-linear amplification weight vector after non-linear transformation; All elements in the non-linear amplification weight vector are summed and normalized, and the sum of each element remains consistent with the original normalized weight vector, obtaining a sub-frequency band importance weight vector maintaining the relative importance relationship.

10. The local-resonance-acoustics- superstructure-based noise control method for a vehicle pressure relief valve of claim 1, wherein, Obtain the basic data of the target vehicle; based on the basic data of the target vehicle, perform multi-working condition noise test to determine the main noise frequency; based on the main noise frequency, locate the main radiation source of the noise of the positioning pressure relief valve, and analyze the key path of the noise in-vehicle propagation; based on the main noise frequency, the main radiation source and the key path, extract the noise main peak frequency, and determine the core noise reduction frequency band.

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