Vibration absorption cell, low-frequency sound insulation system and low-frequency sound insulation method

Abstract

The invention provides a vibration absorption cell, a low-frequency sound insulation system and a low-frequency sound insulation method.The vibration absorption cell comprises a cantilever beam assembly, a permanent magnet and a coil, and the cantilever beam assembly is of an inverted-L-shaped structure and comprises a vertical part and a horizontal part with one end connected with the top end of the vertical part; the permanent magnet is arranged at the other end of the horizontal part and is parallel to and opposite to the vertical part; the coil is arranged outside the permanent magnet in a sleeving mode, the coil, the permanent magnet and the horizontal part are arranged in a separated mode, the vibration absorption center frequency of the vibration absorption cells can be adjusted under the electromagnetic effect, the vibration absorption cells are made to generate local resonance, a wide vibration absorption frequency band is formed under the mutual coupling effect of the vibration absorption cells, and low-frequency noise of the engine at the corresponding order is absorbed in real time. Therefore, the low-frequency sound insulation effect is improved.

Description

Technical Field

[0001] This application relates to the field of automotive sound insulation technology, and more specifically, to a vibration-absorbing cell, a low-frequency sound insulation system, and a low-frequency sound insulation method. Background Technology

[0002] In the automotive industry, structural noise and air noise generated during engine operation are the main factors affecting the acoustic and vibration comfort inside the vehicle.

[0003] Currently, in terms of noise transmission path optimization, the common approach is to optimize the vehicle body structure design and add acoustic coverings to weaken noise transmission. This has a good attenuation effect in the high-frequency range, but its suppression effect on low-frequency noise is poor. Passive superstructures are usually used to suppress low-frequency noise, but the vibration absorption frequency band of passive superstructures for low-frequency noise reduction is fixed, making it difficult to adaptively adjust according to changes in the external noise environment, resulting in insufficient sound insulation performance in the low-frequency range.

[0004] Therefore, existing technologies for low-frequency sound insulation in automobiles have certain limitations. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the prior art by providing a vibration-absorbing cell, a low-frequency sound insulation system, and a low-frequency sound insulation method, so as to solve the practical problem that the prior art has certain limitations in low-frequency sound insulation for automobiles.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows: In a first aspect, embodiments of this application provide a vibration-absorbing cell, the vibration-absorbing cell comprising: a cantilever beam assembly, a permanent magnet, and a coil; The cantilever beam assembly has a Γ-shaped structure, including a vertical part and a horizontal part with one end connected to the top of the vertical part; The permanent magnet is disposed on the other end of the horizontal part, and the permanent magnet is arranged parallel to and opposite to the vertical part; The coil is sleeved outside the permanent magnet, and the coil is separated from both the permanent magnet and the horizontal part.

[0007] As an optional implementation, the cantilever beam assembly includes a metal layer and damping layers disposed on both sides of the metal layer.

[0008] Secondly, embodiments of this application provide a low-frequency sound insulation system, the low-frequency sound insulation system comprising: a control module and an acoustic superstructure array arranged on the vehicle body panel, the acoustic superstructure array comprising a plurality of vibration-absorbing cell groups, the vibration-absorbing cell groups comprising a plurality of vibration-absorbing cells as described in the first aspect above; The coil of the vibration-absorbing cell is fixedly mounted on the vehicle body panel; the coil of the vibration-absorbing cell is configured to be connected to the control module. The bottom of the vertical part of the vibration-absorbing cell is perpendicular to and fixedly connected to the surface of the vehicle body panel.

[0009] Thirdly, embodiments of this application provide a low-frequency sound insulation method applied to a control module in the low-frequency sound insulation system described in the second aspect above, the method comprising: Real-time acquisition of engine speed data; The excitation frequency of the engine at each stage is determined based on the speed data; Based on the excitation frequency of the engine at each order, generate electromagnetic stiffness control signals corresponding to each order; The electromagnetic stiffness control signals corresponding to each order are sent to each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, so that each vibration-absorbing cell adjusts the vibration-absorbing center frequency under the action of the electromagnetic stiffness control signals, and causes each vibration-absorbing cell to resonate locally and absorb the low-frequency noise of the engine in the corresponding order in real time.

[0010] As an optional implementation, generating electromagnetic stiffness control signals corresponding to each excitation frequency of the engine at each order includes: Based on the excitation frequency of the engine at each order and the property parameters of the corresponding vibration-absorbing cell group at each order, electromagnetic stiffness control signals corresponding to each order are generated in real time.

[0011] As an optional implementation, the attribute parameters of the vibration-absorbing cell group include: the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group and the stiffness of the cantilever beam assembly; The process of generating electromagnetic stiffness control signals for each order in real time based on the excitation frequency of the engine at each order and the property parameters of the corresponding vibration-absorbing cell group at each order includes: Based on the excitation frequency of the engine at each level, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each level, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each level is determined. Based on the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, the electromagnetic stiffness control signal corresponding to each order is generated in real time.

[0012] As an optional implementation, determining the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, based on the engine's excitation frequency at each order, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in each vibration-absorbing cell group corresponding to each order, and the stiffness of the cantilever beam assembly, includes: Based on the second-order excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency is determined. Based on the fourth excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth excitation frequency is determined. Based on the engine's sixth-order excitation frequency, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency is determined.

[0013] As an optional implementation, determining the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, based on the engine's second-order excitation frequency, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly, includes: The second-order excitation frequency of the engine is used as the target vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency. Based on the target vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency, the effective mass of the cantilever beam assembly, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency is determined.

[0014] As an optional implementation, the step of generating electromagnetic stiffness control signals corresponding to each order in real time based on the target electromagnetic stiffness of each vibration-absorbing cell in the corresponding vibration-absorbing cell group includes: Based on the target electromagnetic stiffness of each absorbing cell in the corresponding absorbing cell group of each order, determine the target current of the coil of each absorbing cell in the corresponding absorbing cell group of each order. Based on the target current of the coil of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, the electromagnetic stiffness control signal corresponding to each order is generated in real time.

[0015] As an optional implementation, the method further includes: The feedback data sent by the sensors in the low-frequency sound insulation system is acquired in real time. The feedback data is used to indicate the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order. Based on the feedback data, determine whether to correct the electromagnetic stiffness control signals corresponding to each order; If so, the electromagnetic stiffness control signals corresponding to each order are modified so as to correct the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order based on the modified electromagnetic stiffness control signals corresponding to each order.

[0016] As an optional implementation, determining whether to modify the electromagnetic stiffness control signals corresponding to each order based on the feedback data includes: Based on the feedback data, determine the difference between the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order and the excitation frequency of the engine in the corresponding order. If the difference is greater than a preset threshold, then determine to correct the electromagnetic stiffness control signal corresponding to each order.

[0017] Fourthly, embodiments of this application provide a vehicle including the low-frequency sound insulation system described in the second aspect above.

[0018] The beneficial effects of this application are: This application provides a vibration-absorbing cell, a low-frequency sound insulation system, and a low-frequency sound insulation method. The vibration-absorbing cell includes a cantilever beam assembly, a permanent magnet, and a coil. The cantilever beam assembly has a Γ-shaped structure, including a vertical part and a horizontal part connected to the top of the vertical part at one end. The permanent magnet is disposed on the other end of the horizontal part, parallel and opposite to the vertical part. The coil is sleeved outside the permanent magnet, and the coil is separated from both the permanent magnet and the horizontal part. Because the coil is fixedly mounted on the vehicle body panel and connected to the control module, the vibration-absorbing cell can adjust its vibration-absorbing center frequency under electromagnetic action, causing each vibration-absorbing cell to resonate locally. The mutual coupling of the vibration-absorbing cells forms a relatively wide vibration-absorbing frequency band, absorbing low-frequency noise from the engine at the corresponding level in real time. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the architecture of a low-frequency sound insulation system provided in an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the vibration-absorbing cell provided in the embodiments of this application; Figure 3 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 1 ; Figure 4 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 2 ; Figure 5 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 3 ; Figure 6 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 4 ; Figure 7 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 5 ; Figure 8 This is a schematic diagram comparing the sound insulation of the vehicle body panel when the coil is energized with different currents, as provided in the embodiments of this application.

[0021] Reference numerals: Control module: 10; Acoustic superstructure array: 20; Vehicle body panel: 30; Engine speed detection device: 40; Sensor: 50; Vibration-absorbing cell group: 21; Vibration-absorbing cell: 22; Cantilever beam assembly: 221; Permanent magnet: 222; Coil: 223; Metal layer: 2211; First damping layer: 2212; Second damping layer: 2213. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0023] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0024] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0025] In the automotive field, structural noise and airborne noise generated during engine operation are the main factors affecting in-vehicle acoustic comfort. Currently, in terms of noise transmission path optimization, measures such as optimizing the vehicle body structure design and adding acoustic coverings are commonly used to reduce noise transmission. This has a good attenuation effect in the high-frequency range, but its suppression effect on low-frequency noise is poor. Passive superstructures are usually used to suppress low-frequency noise, but the vibration absorption frequency band of passive superstructures for low-frequency noise reduction is fixed, making it difficult to adaptively adjust according to changes in the external noise environment, resulting in insufficient sound insulation performance in the low-frequency range. Some adjustable superstructures adjust the vibration absorption frequency band of the acoustic superstructure by sliding and adjusting the effective length of the cantilever beam, but this relies on manual adjustment, resulting in low adjustment efficiency and a low degree of automation. In other words, existing technologies for low-frequency sound insulation in automobiles have limitations such as insufficient low-frequency sound insulation performance, lack of adjustability of passive superstructures, and insufficient intelligence in the adjustment methods of adjustable superstructures.

[0026] Based on the above-mentioned problems, this application provides a vibration-absorbing cell, which includes a cantilever beam assembly, a permanent magnet and a coil. The vibration-absorbing center frequency of the vibration-absorbing cell is dynamically and adaptively adjustable through electromagnetic action. The vibration-absorbing cell absorbs low-frequency noise from the engine in real time, thereby improving the sound insulation effect of the whole vehicle in the low-frequency range.

[0027] This application provides a low-frequency sound insulation system, which includes a control module and an acoustic superstructure array arranged on the vehicle body panel. The acoustic superstructure array includes multiple vibration-absorbing cell groups, and each vibration-absorbing cell group includes multiple vibration-absorbing cells.

[0028] Specifically, Figure 1 This is a schematic diagram of the architecture of the low-frequency sound insulation system provided in the embodiments of this application, such as... Figure 1 As shown, the low-frequency sound insulation system includes: a control module 10 and an acoustic superstructure array 20 arranged on the vehicle body panel 30. The acoustic superstructure array 20 includes multiple vibration-absorbing cell groups 21, and the vibration-absorbing cell groups 21 include multiple vibration-absorbing cells 22.

[0029] The coil 223 of the vibration-absorbing cell 22 is fixedly mounted on the vehicle body panel 30, and the coil 223 of the vibration-absorbing cell 22 is configured to be connected to the control module 10.

[0030] The bottom of the vertical part of the vibration-absorbing cell 22 is perpendicular to and fixedly connected to the surface of the vehicle body panel 30.

[0031] Before deploying the acoustic superstructure array 20, modal analysis is used to accurately identify the vibration modes of the vehicle body panels 30 along the noise propagation paths, such as the front bulkhead and dashboard beams. Each vibration mode corresponds to the engine's main excitation frequency, such as the second, fourth, and sixth excitation frequencies. Based on the strain energy distribution or displacement contour map of each vibration mode, the vibration-absorbing cells 22 are arranged in groups in the anti-node region of the vehicle with the largest amplitude. The anti-node region corresponds to the wave crest of the vibration, i.e., the region with the largest displacement and the strongest vibration energy. This ensures that each vibration-absorbing cell 22 in each group 21 can be excited by the strongest energy vibration, maximizing the capture of vibration energy during each excitation, and dissipating it through the resonance of the vibration-absorbing cells 22.

[0032] To address the structural characteristics and sound insulation requirements of different areas of the vehicle, the 21 vibration-absorbing cell groups can be arranged in a regional array to form an acoustic superstructure array 20. For example, refer to... Figure 1 In the large flat area of ​​the front panel of the vehicle, each vibration-absorbing cell group 21 can be arranged in a matrix array. By utilizing the coupling effect between the vibration-absorbing cells 22, multiple adjacent narrow vibration-absorbing frequency bands can be merged and widened to form a wide and deep vibration-absorbing frequency band, which can suppress a wide range of low-frequency noise on a "surface" basis.

[0033] In areas with complex structures and limited space, such as dashboards, the vibration-absorbing cell groups 21 can be arranged in a ring or strip array to avoid installation interference and precisely suppress the propagation of bending waves on the "line" of structural components such as dashboard beams.

[0034] Each individual vibration-absorbing cell 22 is only for a single vibration-absorbing center frequency (i.e., resonant frequency), such as a narrow vibration-absorbing frequency band of 200Hz. However, through the above-mentioned array arrangement, the vibration-absorbing cells 22 can be coupled with each other and with the substrate (i.e., the vehicle body panel 30), generating more vibration modes and merging and widening their respective independent narrow vibration-absorbing frequency bands, such as forming a wider vibration-absorbing frequency band of 180Hz-220Hz, thus achieving broadband noise reduction in low frequencies.

[0035] Continue to refer to Figure 1 Each vibration-absorbing cell group 21 is used to match the excitation frequency of the engine at each order. Each vibration-absorbing cell group 21 includes multiple vibration-absorbing cells 22. The vibration-absorbing cells 22 in a group of vibration-absorbing cells 21 are arranged in an array and coupled to each other to widen the vibration absorption bandwidth and improve the vibration absorption effect. This can ensure stable coverage of the engine's frequency changes at the corresponding order, so as to absorb the low-frequency noise of the engine at the corresponding order in real time.

[0036] The control module 10 pre-stores a mapping table between the excitation frequency order of the engine and the group identifiers of each vibration-absorbing cell group 21. Each excitation frequency of the engine has a corresponding vibration-absorbing cell group 21, specifically designed to absorb low-frequency noise at the corresponding order. For example, the first group of vibration-absorbing cells is specifically designed to absorb low-frequency noise at the second order, the second group is specifically designed to absorb low-frequency noise at the fourth order, and the third group is specifically designed to absorb low-frequency noise at the sixth order.

[0037] The control module 10 is connected to the engine speed detection device 40 to acquire engine speed data in real time and obtain the engine's excitation frequency at each order based on the speed data. The control module 10 also generates electromagnetic stiffness control signals corresponding to each order of the engine's excitation frequency based on the engine's excitation frequency at each order. Based on a pre-stored mapping table of the order of the engine's excitation frequency and the group identifiers of each vibration-absorbing cell group 21, the control module 10 accurately sends the electromagnetic stiffness control signals corresponding to each order to each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21. This causes each vibration-absorbing cell 22 to adjust its vibration-absorbing center frequency under the action of the electromagnetic stiffness control signals, resulting in local resonance of each vibration-absorbing cell 22. The mutual coupling of the vibration-absorbing cells 22 forms a relatively wide vibration-absorbing frequency band, absorbing low-frequency noise from the engine at the corresponding order in real time.

[0038] Continue to refer to Figure 1 The low-frequency sound insulation system also includes a sensor 50. The control module 10 is connected to the sensor 50 to receive feedback data sent by the sensor 50. When a preset correction condition is met, the control module 10 corrects the electromagnetic stiffness control signal corresponding to each order based on the feedback data, thereby correcting the adjusted vibration absorption center frequency of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order, ensuring vibration absorption accuracy and improving the low-frequency noise suppression effect. For example, the preset correction condition may be that the adjusted vibration absorption center frequency of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order deviates significantly from the excitation frequency of the engine in the corresponding order. In this case, it is necessary to correct the electromagnetic stiffness control signal corresponding to each order to improve vibration absorption accuracy.

[0039] This application embodiment also provides a vibration-absorbing cell 22, which includes: a cantilever beam assembly 221, a permanent magnet 222, and a coil 223. The cantilever beam assembly has a Γ-shaped structure, including a vertical part and a horizontal part with one end connected to the top of the vertical part. The permanent magnet is disposed on the other end of the horizontal part, and the permanent magnet is parallel to and opposite to the vertical part. The coil is sleeved on the permanent magnet, and the coil is separated from both the permanent magnet and the horizontal part.

[0040] Specifically, Figure 2 This is a schematic diagram of the structure of the vibration-absorbing cell provided in the embodiments of this application, as shown below. Figure 2As shown, in the vibration-absorbing cell 22, the bottom of the vertical part of the cantilever beam assembly 221, which has a Γ-shaped structure, is fixed to the vehicle body panel 30 by welding or high-strength adhesive, forming a tight coupling relationship with the vehicle body base. The top of the vertical part of the cantilever beam assembly 221 is connected to one end of the horizontal part, and a permanent magnet 222 is installed at the other end of the horizontal part. The permanent magnet 222 is arranged parallel to and opposite to the vertical part.

[0041] The permanent magnet 222 is fitted with a coil 223, and the coil 223 is separated from the permanent magnet 222 and the horizontal part. The coil 223 is fixedly mounted on the vehicle body panel 30 and is connected to the control module 10.

[0042] In this embodiment, the vibration-absorbing cell includes a cantilever beam assembly, a permanent magnet, and a coil. The cantilever beam assembly has a Γ-shaped structure, including a vertical part and a horizontal part connected to the top of the vertical part at one end. The permanent magnet is disposed on the other end of the horizontal part, and is arranged parallel to and opposite to the vertical part. The coil is sleeved on the permanent magnet, and is separated from both the permanent magnet and the horizontal part. Since the coil is fixedly mounted on the vehicle body panel and is connected to the control module, the vibration-absorbing cell can adjust the vibration-absorbing center frequency under electromagnetic action, causing each vibration-absorbing cell to resonate locally. Under the mutual coupling of the vibration-absorbing cells, a relatively wide vibration-absorbing frequency band is formed, which absorbs the low-frequency noise of the engine in the corresponding order in real time.

[0043] As an alternative implementation, the cantilever beam assembly 221 includes a metal layer 2211 and damping layers disposed on both sides of the metal layer 2211.

[0044] Optionally, continue to refer to Figure 2 The damping layer may include a first damping layer 2212 and a second damping layer 2213, wherein the first damping layer 2212 covers the upper surface of the metal layer 2211, and the second damping layer 2213 covers the lower surface of the metal layer 2211. The metal layer 2211 may be made of stainless steel, and the first damping layer 2212 and the second damping layer 2213 may be made of basic polymer materials such as polyurethane rubber, silicone rubber, butyl rubber, or polyvinyl chloride.

[0045] The damping layer can broaden the resonance response of the vibration-absorbing cell 22, significantly suppress the resonance amplitude, rapidly attenuate vibration, improve the dynamic stability of the vibration-absorbing cell 22, and prevent secondary noise radiation.

[0046] In this embodiment, the cantilever beam assembly includes a metal layer and damping layers disposed on both sides of the metal layer. The two damping layers broaden the resonant response of the vibration-absorbing cells and improve their dynamic stability, preventing secondary noise radiation.

[0047] Figure 3 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 1The execution subject of this method is Figure 1 The control module 10 in the low-frequency sound insulation system shown. For example... Figure 3 As shown, the method includes: S101. Real-time acquisition of engine speed data.

[0048] Optionally, in the vehicle noise propagation path, the order noise generated by the engine operation is transmitted into the vehicle through structures such as the front bulkhead and dashboard. The low-frequency noise generated by the engine is the main factor in the degradation of the sound quality inside the vehicle, and it is necessary to suppress the low-frequency noise generated by the engine in a targeted manner.

[0049] Reference Figure 1 The control module 10 acquires the engine speed data in real time through the engine speed detection device 40, which can be a crankshaft position sensor. Specifically, when the crankshaft rotates, the crankshaft speed sensor generates a pulse signal proportional to the engine speed. The control module 10 filters and shapes the pulse signal to obtain the engine speed data.

[0050] S102. Determine the engine excitation frequency at each stage based on the speed data.

[0051] Optionally, the engine excitation frequencies at each order can be calculated based on the engine speed data. Due to the harmonic characteristics of engine vibration excitation, even-numbered orders are the main source of noise, so the excitation frequencies at the second, fourth, and sixth orders are mainly calculated.

[0052] Specifically, the excitation frequency of the engine at each order is obtained by calculating the product of the engine speed and the order number, and then dividing the product by the value 60. This mainly includes the excitation frequencies of the engine at the second, fourth, and sixth orders. In other words, the excitation frequency of the engine at the second order is twice that of the engine at the first order, the excitation frequency of the engine at the fourth order is four times that of the engine at the first order, and the excitation frequency of the engine at the sixth order is six times that of the engine at the first order.

[0053] S103. Generate electromagnetic stiffness control signals corresponding to each excitation frequency of the engine at each level.

[0054] Optionally, the control module 10 generates electromagnetic stiffness control signals corresponding to the second, fourth, and sixth orders according to the excitation frequencies of the engine at the main orders such as the second, fourth, and sixth orders, so as to allocate corresponding electromagnetic stiffness control signals to the vibration-absorbing cell groups 21 corresponding to the second, fourth, and sixth orders, thereby generating targeted electromagnetic stiffness control signals for each order and effectively suppressing the low-frequency noise of the engine at the corresponding order.

[0055] Among them, the second-order electromagnetic stiffness control signal is used to control the second-order vibration-absorbing cell group 21 to absorb the low-frequency noise of the engine in the second order in real time; the fourth-order electromagnetic stiffness control signal is used to control the fourth-order vibration-absorbing cell group 21 to absorb the low-frequency noise of the engine in the fourth order in real time; and the sixth-order electromagnetic stiffness control signal is used to control the sixth-order vibration-absorbing cell group 21 to absorb the low-frequency noise of the engine in the sixth order in real time.

[0056] S104. The electromagnetic stiffness control signals corresponding to each order are sent to each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order, so that each vibration-absorbing cell 22 adjusts the vibration-absorbing center frequency under the action of the electromagnetic stiffness control signals, and causes each vibration-absorbing cell 22 to resonate locally and absorb the low-frequency noise of the engine in the corresponding order in real time.

[0057] Optionally, the control module 10 pre-stores a mapping table between the order of the engine's excitation frequency and the group identifier of each vibration-absorbing cell group 21. The engine has vibration-absorbing cell groups 21 corresponding to each order of excitation frequency. Each vibration-absorbing cell group 21 is specifically used to absorb the low-frequency noise of the engine at the corresponding order.

[0058] According to the pre-stored mapping table of the order of the engine's excitation frequency and the group identifier of each vibration-absorbing cell group 21, the control module 10 sends the electromagnetic stiffness control signal corresponding to each order to each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21 in a directional manner, which can avoid crosstalk or confusion of the electromagnetic stiffness control signals corresponding to each order.

[0059] Each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order adjusts its vibration-absorbing center frequency under the action of the electromagnetic stiffness control signal corresponding to each order. The vibration-absorbing center frequency of the vibration-absorbing cell 22 is used to characterize the center value of the frequency range in which the vibration-absorbing cell 22 can effectively absorb vibration energy. The vibration-absorbing cells 22 in the vibration-absorbing cell group 21 corresponding to each order are coupled to each other and undergo local resonance, which cancels out part of the vibration energy of the vehicle body panel 30, forming a relatively wide vibration-absorbing frequency band corresponding to each order, so as to absorb the low-frequency noise of the engine in the corresponding order in real time.

[0060] Taking each vibration-absorbing cell 22 in the second-order corresponding vibration-absorbing cell group 21 as an example, each vibration-absorbing cell 22 in the second-order corresponding vibration-absorbing cell group 21 adjusts the vibration-absorbing center frequency under the action of the second-order corresponding electromagnetic stiffness control signal. The vibration-absorbing cells 22 in the second-order corresponding vibration-absorbing cell group 21 are coupled to each other and local resonance occurs, forming a relatively wide vibration-absorbing frequency band in the second order, so as to absorb the low-frequency noise of the engine in the second order in real time. Correspondingly, each vibration-absorbing cell 22 in the fourth-order corresponding vibration-absorbing cell group 21 absorbs the low-frequency noise of the engine in the fourth order in real time, and each vibration-absorbing cell 22 in the sixth-order corresponding vibration-absorbing cell group 21 absorbs the low-frequency noise of the engine in the sixth order in real time, thereby achieving effective suppression of the low-frequency noise of the engine in the main order and improving the sound insulation effect of the whole vehicle in the low-frequency range.

[0061] In this embodiment, the control module acquires the engine speed data in real time, determines the engine's excitation frequency at each order based on the speed data and engine attribute parameters, and generates corresponding electromagnetic stiffness control signals for each order, sending them to the corresponding vibration-absorbing cells in the vibration-absorbing cell group. Under the action of the electromagnetic stiffness control signals, each vibration-absorbing cell adjusts its vibration-absorbing center frequency and couples with each other, resulting in local resonance and forming a relatively wide vibration-absorbing frequency band for each order, thus absorbing low-frequency noise from the engine at the corresponding order in real time. By arranging the vibration-absorbing cell groups in a regional array to form an acoustic superstructure array, the coupling effect between the vibration-absorbing cells can be used to merge and widen multiple adjacent narrow vibration-absorbing frequency bands, offsetting some of the vibration energy of the vehicle body panels, forming a wide and deep vibration-absorbing frequency band, and specifically absorbing low-frequency noise of the corresponding order in real time, greatly improving the low-frequency sound absorption effect.

[0062] As an optional implementation, step S103 above, which generates electromagnetic stiffness control signals corresponding to each excitation frequency of the engine at each level, includes: Based on the excitation frequency of the engine at each level and the attribute parameters of the corresponding vibration-absorbing cell group 21, the electromagnetic stiffness control signal corresponding to each level is generated in real time.

[0063] Optionally, the control module 10 can deduce the electromagnetic stiffness required by the vibration-absorbing cell group 21 at each level to absorb the low-frequency noise of the engine at the corresponding level by using dynamic formulas based on the excitation frequency of the engine at each level and the property parameters of the vibration-absorbing cell group 21 at each level.

[0064] The control module 10 generates electromagnetic stiffness control signals in real time according to the electromagnetic stiffness required by the corresponding vibration-absorbing cell group 21 to absorb the low-frequency noise of the engine at the corresponding level. This allows each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21 to adjust its own electromagnetic stiffness to the electromagnetic stiffness required by the engine at the corresponding level when absorbing the low-frequency noise of the engine. This, in turn, adjusts the vibration absorption center frequency of each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21. As a result, the vibration absorption center frequency of each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21 resonates locally with the excitation frequency of the engine at the corresponding level, thereby offsetting part of the vibration energy of the vehicle body panel 30. A local vibration absorption effect is formed near the adjusted vibration absorption center frequency, effectively suppressing the transmission of low-frequency sound energy.

[0065] In this embodiment, the control module generates electromagnetic stiffness control signals for each order in real time based on the engine's excitation frequency at each order and the attribute parameters of the corresponding vibration-absorbing cell groups. This ensures that each vibration-absorbing cell in each order's vibration-absorbing cell group, under the influence of the corresponding electromagnetic stiffness control signals, adjusts its electromagnetic stiffness to the level required for absorbing low-frequency noise from the engine at the corresponding order. This, in turn, adjusts the vibration-absorbing center frequency of each vibration-absorbing cell in each order's vibration-absorbing cell group. Consequently, the adjusted vibration-absorbing center frequency of each vibration-absorbing cell resonates locally with the engine's excitation frequency at the corresponding order, offsetting some of the vibration energy of the vehicle body panel. This creates a localized vibration-absorbing effect near the adjusted vibration-absorbing center frequency, effectively suppressing the transmission of low-frequency sound energy.

[0066] As an optional implementation, the property parameters of the vibration-absorbing cell group 21 include: the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 and the stiffness of the cantilever beam assembly 221.

[0067] Specifically, the attribute parameters of the vibration-absorbing cell group 21 include the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21. and the stiffness of the cantilever beam assembly 221 Among them, the effective mass of the cantilever beam assembly 221 The concentrated mass of the cantilever beam assembly 221, equivalent to the vibration direction, is an inertial factor affecting the absorption center frequency of the vibration-absorbing cell 22. The stiffness of the cantilever beam assembly 221... The material and geometry of the cantilever beam assembly 221 determine its ability to resist elastic deformation.

[0068] Figure 4 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 2 ,like Figure 4As shown, in the above steps, based on the engine's excitation frequency at each order and the attribute parameters of the corresponding vibration-absorbing cell group 21, electromagnetic stiffness control signals for each order are generated in real time, including: S201. Based on the excitation frequency of the engine at each level, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each level, and the stiffness of the cantilever beam assembly 221, determine the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each level.

[0069] Optionally, the natural frequency of the vibration-absorbing cell 22 must perfectly match the excitation frequency of the engine at the corresponding order in order to generate local resonance for vibration absorption. The natural frequency of the vibration-absorbing cell 22 is the vibration-absorbing center frequency adjusted by the electromagnetic stiffness control signal.

[0070] The natural frequency of the vibration-absorbing cell 22 is determined by the effective mass of the cantilever beam assembly 221. Stiffness of cantilever beam assembly 221 The electromagnetic stiffness is determined by the electromagnetic force between the coil 223 and the permanent magnet 222 as a function of the axial displacement of the permanent magnet 222. It is used to characterize the degree of change of the electromagnetic force caused by the axial displacement of the permanent magnet 222.

[0071] The control module 10, based on the engine's excitation frequency at each order, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21, and the stiffness of the cantilever beam assembly 221, derives the electromagnetic stiffness required by the corresponding vibration-absorbing cell group 21 to absorb the engine's low-frequency noise at the corresponding order, i.e., the target electromagnetic stiffness of each vibration-absorbing cell 22 in the corresponding vibration-absorbing cell group 21, through a dynamic formula. The dynamic formula can be a resonance formula.

[0072] S202. Based on the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order, generate electromagnetic stiffness control signals corresponding to each order in real time.

[0073] Optionally, the control module 10 converts the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 into driving parameters according to the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 of each order, and generates electromagnetic stiffness control signals for each order.

[0074] The driving parameter can be the current flowing through coil 223. The magnitude of the electromagnetic stiffness is related to the magnetic induction intensity of coil 223, which is directly controlled by the current flowing through coil 223. When the magnitude of the current flowing through coil 223 is adjusted by the corresponding electromagnetic stiffness control signals of each order, the electromagnetic stiffness of the vibration-absorbing cell 22 can be quickly adjusted without changing the geometry of the vibration-absorbing cell 22. This changes the natural frequency of the vibration-absorbing cell 22, i.e., the vibration-absorbing center frequency, so that the adjusted vibration-absorbing center frequency of the vibration-absorbing cell 22 matches the excitation frequency of the engine at the corresponding order, resulting in local resonance for vibration absorption. This achieves adaptive matching and absorption of order noise frequencies of the engine under idling, acceleration, and constant speed cruising conditions, realizing dynamic vibration absorption.

[0075] In this embodiment, the attribute parameters of the vibration-absorbing cell group include the effective mass and stiffness of the cantilever beam assembly of each vibration-absorbing cell in the group. The control module determines the target electromagnetic stiffness of each vibration-absorbing cell in each level of the vibration-absorbing cell group based on the engine's excitation frequency at each level, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in each level of the vibration-absorbing cell group, and the stiffness of the cantilever beam assembly. Based on the target electromagnetic stiffness of each vibration-absorbing cell in each level of the vibration-absorbing cell group, the module generates electromagnetic stiffness control signals for each level of the vibration-absorbing cell group in real time. This allows for rapid adjustment of the electromagnetic stiffness of the vibration-absorbing cells without changing their geometry, thereby changing the natural frequency of the vibration-absorbing cells, i.e., the vibration-absorbing center frequency. This ensures that the adjusted vibration-absorbing center frequency of the vibration-absorbing cells matches the engine's excitation frequency at the corresponding level, resulting in local resonance for vibration absorption.

[0076] Figure 5 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 3 ,like Figure 5 As shown, in step S201 above, the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order is determined based on the engine's excitation frequency at each order, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in each order's vibration-absorbing cell group 21, and the stiffness of the cantilever beam assembly 221, including: S301. Based on the engine's second-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly 221, determine the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency.

[0077] Optionally, the control module 10, based on the engine's second-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly 221, derives the electromagnetic stiffness required by the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency to absorb the engine's second-order low-frequency noise through the resonance formula, and uses it as the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency.

[0078] If the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency are consistent, then the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency is the same. If there are individual differences in the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency, the effective mass and stiffness of the cantilever beam assembly 221 of different vibration-absorbing cells 22 can be adapted to determine the target electromagnetic stiffness of different vibration-absorbing cells 22, ensuring that the natural frequency, i.e., the vibration absorption center frequency, of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency can accurately match the second-order excitation frequency of the engine after adjustment.

[0079] S302. Based on the fourth-order excitation frequency of the engine, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth-order excitation frequency, and the stiffness of the cantilever beam assembly 221, determine the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth-order excitation frequency.

[0080] Optionally, the control module 10, based on the engine's fourth-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth-order excitation frequency, and the stiffness of the cantilever beam assembly 221, derives the electromagnetic stiffness required by the vibration-absorbing cell group 21 corresponding to the fourth-order excitation frequency to absorb the engine's low-frequency noise in the fourth order through the resonance formula, and uses it as the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth-order excitation frequency.

[0081] If the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth excitation frequency are consistent, then the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth excitation frequency is the same. If there are individual differences in the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth excitation frequency, the effective mass and stiffness of the cantilever beam assembly 221 of different vibration-absorbing cells 22 can be adapted to determine the target electromagnetic stiffness of different vibration-absorbing cells 22, ensuring that the natural frequency, i.e., the vibration absorption center frequency, of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth excitation frequency can accurately match the fourth excitation frequency of the engine after adjustment.

[0082] S303. Based on the engine's sixth-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth-order excitation frequency, and the stiffness of the cantilever beam assembly 221, determine the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth-order excitation frequency.

[0083] Optionally, the control module 10, based on the engine's sixth-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth-order excitation frequency, and the stiffness of the cantilever beam assembly 221, derives the electromagnetic stiffness required by the vibration-absorbing cell group 21 corresponding to the sixth-order excitation frequency to absorb the engine's low-frequency noise at the sixth order through the resonance formula, and uses it as the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth-order excitation frequency.

[0084] If the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth excitation frequency are consistent, then the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth excitation frequency is the same. If there are individual differences in the effective mass and stiffness of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth excitation frequency, the effective mass and stiffness of the cantilever beam assembly 221 of different vibration-absorbing cells 22 can be adapted to determine the target electromagnetic stiffness of different vibration-absorbing cells 22, ensuring that the natural frequency, i.e., the vibration absorption center frequency, of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth excitation frequency can accurately match the sixth excitation frequency of the engine after adjustment.

[0085] In this embodiment, the control module determines the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly. It also determines the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth-order excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth-order excitation frequency, and the stiffness of the cantilever beam assembly. Finally, it determines the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency, and the stiffness of the cantilever beam assembly. This is to accurately absorb low-frequency noise caused by the engine's main excitation frequencies, namely the second-order, fourth-order, and sixth-order excitation frequencies.

[0086] As an optional implementation, in step S301 above, the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency is determined based on the engine's second-order excitation frequency, the effective mass of the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly 221, including: The second-order excitation frequency of the engine is used as the target vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to the second-order excitation frequency. Based on the target vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to the second-order excitation frequency, the effective mass of the cantilever beam assembly 221, and the stiffness of the cantilever beam assembly 221, the target electromagnetic stiffness of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to the second-order excitation frequency is determined.

[0087] Optionally, the natural frequency of the absorbing cell 22 The expression is as follows:

[0088] in, This is the natural frequency of the absorbing cell 22, i.e., the absorption center frequency of the absorbing cell 22. For the stiffness of the cantilever beam assembly 221 of the vibration-absorbing unit cell 22, The effective mass of the cantilever beam assembly 221 of the vibration-absorbing cell 22, Let be the electromagnetic stiffness of the vibration-absorbing cell 22.

[0089] To match the engine's second-order excitation frequency, the engine's second-order excitation frequency is used as the target vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to the second-order excitation frequency. In other words, the engine's second-order excitation frequency is used as the natural frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to the second-order excitation frequency. Substituting into the above expression, and considering the effective mass of the cantilever beam assembly 221 of each absorbing cell 22 in the absorbing cell group 21 corresponding to the second-order excitation frequency... and the stiffness of the cantilever beam assembly 221 Substituting into the above expression, the target electromagnetic stiffness of each absorbing cell 22 in the absorbing cell group 21 corresponding to the second-order excitation frequency is derived in reverse.

[0090] This allows the cantilever beam assembly 221 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second-order excitation frequency to resonate locally with the permanent magnet 222, forming a local vibration-absorbing effect near the second-order excitation frequency of the engine, and accurately absorbing the low-frequency noise of the engine in the second order.

[0091] In this embodiment, the second-order excitation frequency of the engine is used as the target vibration absorption center frequency of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency. Based on the target vibration absorption center frequency of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, the effective mass of the cantilever beam assembly, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency is derived in reverse. This causes the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency to resonate locally with the permanent magnet, forming a local vibration absorption effect near the second-order excitation frequency of the engine, accurately absorbing the engine's low-frequency noise in the second order.

[0092] It is worth noting that the steps of the control module 10 in determining the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the fourth excitation frequency and the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the sixth excitation frequency are similar to the steps in determining the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to the second excitation frequency, and will not be elaborated here.

[0093] Figure 6 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 4 ,like Figure 6 As shown, in step S202 above, electromagnetic stiffness control signals for each order are generated in real time based on the target electromagnetic stiffness of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order, including: S401. Based on the target electromagnetic stiffness of each absorbing cell 22 in the absorbing cell group 21 corresponding to each order, determine the target current of the coil 223 of each absorbing cell 22 in the absorbing cell group 21 corresponding to each order.

[0094] Optionally, the control module 10 determines the target current of the coil 223 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order based on the target electromagnetic stiffness of each vibration-absorbing cell 22 in each order and through a pre-calibrated mapping relationship between electromagnetic stiffness and current.

[0095] The target electromagnetic stiffness is related to the magnetic induction intensity of coil 223, which is directly controlled by the target current of coil 223. By adjusting the target current flowing through coil 223 through the corresponding electromagnetic stiffness control signals of each order, the target electromagnetic stiffness of the vibration-absorbing cell 22 can be quickly adjusted without changing the geometry of the vibration-absorbing cell 22.

[0096] S402. Based on the target current of the coil 223 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 of each order, generate the corresponding electromagnetic stiffness control signal in real time.

[0097] Optionally, the control module 10 generates electromagnetic stiffness control signals corresponding to each order in real time based on the target current of the coil 223 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 of each order. This causes the current flowing through the coil 223 of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 of each order to be adjusted to the target current value under the action of the electromagnetic stiffness control signals. This changes the target electromagnetic stiffness of the vibration-absorbing cell 22, thereby adjusting the vibration-absorbing center frequency of the vibration-absorbing cell 22. The adjusted vibration-absorbing center frequency of the vibration-absorbing cell 22 is then matched with the excitation frequency of the engine in the corresponding order, resulting in local resonance for dynamic vibration absorption.

[0098] In this embodiment, the control module determines the target current of the coil of each vibration-absorbing cell in each vibration-absorbing cell group based on the target electromagnetic stiffness of each cell in each order, through a pre-calibrated mapping relationship between electromagnetic stiffness and current. Based on the target current of the coil of each vibration-absorbing cell in each order, the control module generates electromagnetic stiffness control signals for each order in real time. This causes each vibration-absorbing cell in each order to adjust the current flowing through its coil to the target current value under the action of the electromagnetic stiffness control signals, thereby changing the target electromagnetic stiffness of the vibration-absorbing cell and adjusting its vibration absorption center frequency. This ensures that the adjusted vibration absorption center frequency matches the engine's excitation frequency in the corresponding order, resulting in local resonance and achieving dynamic vibration absorption.

[0099] Figure 7 Flowchart of the low-frequency sound insulation method provided in the embodiments of this application Figure 5 ,like Figure 7 As shown, the method also includes: S501: Real-time acquisition of feedback data sent by sensor 50 in low-frequency sound insulation system. The feedback data is used to indicate the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order.

[0100] Optionally, continue to refer to Figure 1 The control module 10 is connected to the sensor 50 in the low-frequency sound insulation system to acquire feedback data sent by the sensor 50 in real time. The feedback data is used to indicate the adjusted vibration absorption center frequency of each vibration-absorbing cell 22 in the vibration-absorbing cell group 21 corresponding to each order.

[0101] Specifically, the sensor 50 can collect the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order in real time and feed it back to the control module 10 in real time so that the control module 10 can evaluate the vibration absorption effect of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order.

[0102] S502. Based on the feedback data, determine whether to correct the electromagnetic stiffness control signals corresponding to each order.

[0103] Optionally, the control module 10 evaluates the vibration absorption effect of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order based on the adjusted vibration absorption center frequency indicated by the feedback data, and in combination with the excitation frequency of the engine in each order under the current operating condition, and obtains the evaluation result. The evaluation result is used to characterize the degree of deviation between the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order and the excitation frequency of the engine in the corresponding order.

[0104] Based on the evaluation results, the control module 10 determines whether to modify the electromagnetic stiffness control signals corresponding to each order, so as to maintain a stable and reliable low-frequency sound insulation effect throughout the entire engine speed range.

[0105] S503. If so, then modify the electromagnetic stiffness control signal corresponding to each order, so as to modify the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order based on the modified electromagnetic stiffness control signal corresponding to each order.

[0106] Optionally, if it is determined that the electromagnetic stiffness control signals corresponding to each order need to be corrected, the control module 10 corrects the electromagnetic stiffness control signals corresponding to each order based on the evaluation results. Specifically, if the deviation between the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order, as characterized by the evaluation results, and the excitation frequency of the engine in the corresponding order is greater, then the correction force of the electromagnetic stiffness control signals corresponding to each order will be greater.

[0107] By modifying the electromagnetic stiffness control signals corresponding to each order, the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order can be corrected based on the modified electromagnetic stiffness control signals corresponding to each order. This makes the adjusted vibration absorption center frequency of each vibration absorption cell 22 after modification match the excitation frequency of the engine in the corresponding order, thereby causing the modified vibration absorption cell 22 to resonate locally, accurately absorbing the low-frequency noise of the engine in the corresponding order, ensuring vibration absorption accuracy, and improving the low-frequency noise suppression effect.

[0108] In this embodiment, the control module acquires feedback data sent by the sensor in real time. Based on the adjusted vibration absorption center frequency of each vibration-absorbing cell in the corresponding vibration-absorbing cell group indicated by the feedback data, it determines whether to correct the electromagnetic stiffness control signal for each order. If so, the electromagnetic stiffness control signal for each order is corrected, and the adjusted vibration absorption center frequency of each vibration-absorbing cell in the corresponding vibration-absorbing cell group is corrected based on the corrected electromagnetic stiffness control signal. This ensures a stable and reliable low-frequency sound insulation effect across the entire engine speed range, guarantees vibration absorption accuracy, and improves low-frequency noise suppression.

[0109] As an optional implementation, step S102 above, which determines whether to correct the electromagnetic stiffness control signals corresponding to each order based on the feedback data, includes: Based on the feedback data, determine the difference between the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order and the excitation frequency of the engine in the corresponding order. If the difference is greater than the preset threshold, then determine the correction of the electromagnetic stiffness control signal corresponding to each order.

[0110] Optionally, the control module 10 determines the difference between the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order and the excitation frequency of the engine in the corresponding order based on the feedback data. If the difference is greater than a preset threshold, it indicates that the deviation between the adjusted vibration absorption center frequency of each vibration absorption cell 22 in the vibration absorption cell group 21 corresponding to each order and the excitation frequency of the engine in the corresponding order is relatively high, and the vibration absorption accuracy needs to be further improved. In this case, the control module 10 determines that the electromagnetic stiffness control signal corresponding to each order needs to be corrected to improve the vibration absorption accuracy.

[0111] In this embodiment, the control module determines the difference between the adjusted vibration absorption center frequency of each vibration-absorbing cell in the corresponding vibration-absorbing cell group and the engine's excitation frequency in the corresponding order based on feedback data. If the difference is greater than a preset threshold, the control module determines to correct the electromagnetic stiffness control signal for each order. By introducing a feedback mechanism, the vibration absorption frequency band of each vibration-absorbing cell in the corresponding vibration-absorbing cell group always covers the engine's current excitation frequency in each order, ensuring a stable and reliable low-frequency sound insulation effect across the entire engine speed range.

[0112] Figure 8 This is a comparative schematic diagram showing the sound insulation of the vehicle body panel 30 when different energizing currents flow through the coil 223, as provided in the embodiments of this application. Figure 8 As shown, when different currents flow through the coil 223 of the vibration-absorbing cell 22, a composite sound insulation of up to 15dB can be achieved in the low-frequency band of 140Hz-160Hz, which has a good sound insulation effect on low-frequency noise.

[0113] This application also provides a vehicle that includes the low-frequency sound insulation system described in the foregoing embodiments.

[0114] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems and devices described above can be referred to the corresponding processes in the method embodiments, and will not be repeated here. In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. The device embodiments described above are merely illustrative. For example, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling or direct coupling or communication connection can be through some communication interfaces; the indirect coupling or communication connection of devices or modules can be electrical, mechanical, or other forms.

[0115] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. If the functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes: USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, optical disks, and other media capable of storing program code.

[0116] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A vibration-absorbing cell, characterized in that, The vibration-absorbing unit includes a cantilever beam assembly, a permanent magnet, and a coil; The cantilever beam assembly has a Γ-shaped structure, including a vertical part and a horizontal part with one end connected to the top of the vertical part; The permanent magnet is disposed on the other end of the horizontal part, and the permanent magnet is arranged parallel to and opposite to the vertical part; The coil is sleeved outside the permanent magnet, and the coil is separated from both the permanent magnet and the horizontal part.

2. The vibration-absorbing cell according to claim 1, characterized in that, The cantilever beam assembly includes a metal layer and a damping layer disposed on both sides of the metal layer.

3. A low-frequency sound insulation system, characterized in that, The low-frequency sound insulation system includes: a control module and an acoustic superstructure array arranged on the vehicle body panel, the acoustic superstructure array including multiple vibration-absorbing cell groups, the vibration-absorbing cell groups including multiple vibration-absorbing cells as described in claim 1 or 2; The coil of the vibration-absorbing cell is fixedly mounted on the vehicle body panel; the coil of the vibration-absorbing cell is configured to be connected to the control module. The bottom of the vertical part of the vibration-absorbing cell is perpendicular to and fixedly connected to the surface of the vehicle body panel.

4. A low-frequency sound insulation method, characterized in that, The control module applied to the low-frequency sound insulation system of claim 3, the method comprising: Real-time acquisition of engine speed data; The excitation frequency of the engine at each stage is determined based on the speed data; Based on the excitation frequency of the engine at each order, generate electromagnetic stiffness control signals corresponding to each order; The electromagnetic stiffness control signals corresponding to each order are sent to each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, so that each vibration-absorbing cell adjusts the vibration-absorbing center frequency under the action of the electromagnetic stiffness control signals, and causes each vibration-absorbing cell to resonate locally and absorb the low-frequency noise of the engine in the corresponding order in real time.

5. The method according to claim 4, characterized in that, The step of generating electromagnetic stiffness control signals corresponding to each excitation frequency of the engine at each order includes: Based on the excitation frequency of the engine at each order and the property parameters of the corresponding vibration-absorbing cell group at each order, electromagnetic stiffness control signals corresponding to each order are generated in real time.

6. The method according to claim 5, characterized in that, The attribute parameters of the vibration-absorbing cell group include: the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group and the stiffness of the cantilever beam assembly. The process of generating electromagnetic stiffness control signals for each order in real time based on the excitation frequency of the engine at each order and the property parameters of the corresponding vibration-absorbing cell group at each order includes: Based on the excitation frequency of the engine at each level, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each level, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each level is determined. Based on the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, the electromagnetic stiffness control signal corresponding to each order is generated in real time.

7. The method according to claim 6, characterized in that, The step of determining the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, based on the engine's excitation frequency at each order, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in each order's vibration-absorbing cell group, and the stiffness of the cantilever beam assembly, includes: Based on the second-order excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency is determined. Based on the fourth excitation frequency of the engine, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the fourth excitation frequency is determined. Based on the engine's sixth-order excitation frequency, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the sixth-order excitation frequency is determined.

8. The method according to claim 7, characterized in that, The step of determining the target electromagnetic stiffness of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency based on the engine's second-order excitation frequency, the effective mass of the cantilever beam assembly of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to the second-order excitation frequency, and the stiffness of the cantilever beam assembly includes: The second-order excitation frequency of the engine is used as the target vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency. Based on the target vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency, the effective mass of the cantilever beam assembly, and the stiffness of the cantilever beam assembly, the target electromagnetic stiffness of each vibration absorption cell in the vibration absorption cell group corresponding to the second-order excitation frequency is determined.

9. The method according to claim 6, characterized in that, The step of generating electromagnetic stiffness control signals for each order in real time based on the target electromagnetic stiffness of each vibration-absorbing cell in the corresponding vibration-absorbing cell group includes: Based on the target electromagnetic stiffness of each absorbing cell in the corresponding absorbing cell group of each order, determine the target current of the coil of each absorbing cell in the corresponding absorbing cell group of each order. Based on the target current of the coil of each vibration-absorbing cell in the vibration-absorbing cell group corresponding to each order, the electromagnetic stiffness control signal corresponding to each order is generated in real time.

10. The method according to claim 4, characterized in that, The method further includes: The feedback data sent by the sensors in the low-frequency sound insulation system is acquired in real time. The feedback data is used to indicate the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order. Based on the feedback data, determine whether to correct the electromagnetic stiffness control signals corresponding to each order; If so, the electromagnetic stiffness control signals corresponding to each order are modified so as to correct the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order based on the modified electromagnetic stiffness control signals corresponding to each order.

11. The method according to claim 10, characterized in that, The step of determining whether to correct the electromagnetic stiffness control signals corresponding to each order based on the feedback data includes: Based on the feedback data, determine the difference between the adjusted vibration absorption center frequency of each vibration absorption cell in the vibration absorption cell group corresponding to each order and the excitation frequency of the engine in the corresponding order. If the difference is greater than a preset threshold, then determine to correct the electromagnetic stiffness control signal corresponding to each order.

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