Device for acoustic treatment of ventilation system

Abstract

The invention relates to an acoustic treatment device for a cooling system of a vehicle. The invention relates to an acoustic treatment device (1) intended to be mounted to a cooling system of a vehicle and comprising at least one wall (4) participating in delimiting a duct (2) for the circulation of an air flow, the acoustic treatment device (1) comprising at least one array of resonators (16), and at least one resonator array formed by one or more rows (18) of resonators (16) arranged around the pipe (2) perpendicular to the axis of elongation (A) of the pipe, each resonator (16) in the row (18) of resonators (16) comprising at least a cavity (20) arranged in the wall (4) and a neck (22) connecting the cavity (20) to the pipe (2), characterized in that, for at least a given size of the cavity (20) or of the neck (22), the cavity (20) or the neck (22) forms a cavity (20). At least one resonator (16) of the row (18) has a value different from the value of the corresponding size of the other resonator (16) of the row (18).

Description

Technical Field

[0001] The invention belongs to the field of vehicle ventilation systems and more particularly to the field of devices for the acoustic treatment of such systems, in appropriate cases a vehicle battery cooling system. Background Art

[0002] A vehicle battery cooling system may be located at the front end of the vehicle. The front end module formed thereby comprises means for drawing in air from outside the vehicle and a heat exchanger, whereby the drawn in air is directed through the heat exchanger in order to cool a liquid flowing in the heat exchanger, the liquid being used to cool the batteries within the battery pack of the vehicle. Air is caused to flow through such a cooling system by the operation of a ventilation device, and both such operation and the flow of air within the ducting of the system involve the emission of sound waves, which may cause a considerable level of undesirable noise.

[0003] This undesirable noise phenomenon is even more pronounced in recent electric vehicles, which have bulky battery packs and can be charged via a rapid charging process. When the batteries are charged rapidly, their temperature increases rapidly and the maximum temperature reached is high. In order to compensate for this heating, the ventilation device of the cooling system must be operated at a very high rotation speed, which generates a considerable level of noise outside the vehicle when the vehicle is stopped. This noise can also be annoying to any passengers present inside the vehicle while the batteries are being charged.

[0004] As described in document FR3083298, in order to reduce the acoustic energy radiated at the outlet of the ventilation device, it is known to equip a system equipped with a ventilation device with at least one sound attenuation device. Sound attenuation devices of this type include, for example, an array of Helmholtz resonators. The size and shape of the resonator array are configured to dissipate as much acoustic energy as possible, so as to avoid that the operation of the cooling system is noisy in the surrounding area and / or for the users of the vehicle.

[0005] This type of sound attenuation device generally relies on the absorption of sound waves at the interfaces formed by the walls in order to utilize the dissipative effect to attenuate the sound energy propagating through the duct of the ventilation device, which duct guides the air flow towards the interior of the vehicle, for example.

[0006] However, a motor vehicle front end module comprises blower openings and air intake openings arranged on both sides of one or more heat exchangers, generating low frequency waves between 200 and 1000 Hz, which are highly annoying to pedestrians. These low frequencies with high wavelengths are difficult to handle with conventional sound attenuation devices. This difficulty is greater when the available volume is limited, as is the case with the inlet or blower openings of the front end module, the limited nature of the available volume being defined by the relationship between the available depth of the integrated attenuation device and the wavelength associated with the frequency of the waves to be handled. Summary of the invention

[0007] The present invention aims to improve the existing technical solutions by proposing an acoustic treatment device for installation in a vehicle cooling system, the acoustic treatment device comprising at least one wall, which at least one wall helps to define a duct for air flow, the duct being arranged around an elongated axis parallel to the flow direction of the air flow through the duct, the acoustic treatment device comprising at least one resonator array, the at least one resonator array being formed by a row or line of resonators arranged around the duct, each resonator in a row of resonators comprising at least a cavity arranged in the wall and a neck connecting the cavity to the duct, characterized in that, at least for a given dimension of the cavity or the neck, at least one resonator in the row has a value different from the corresponding dimension of the other resonators in the row.

[0008] The acoustic treatment device according to the invention makes it possible to process multiple sound wave frequencies with a single row of resonators and therefore has a smaller space requirement. The acoustic treatment device thus makes it possible to process sound waves over a given frequency bandwidth. This frequency bandwidth will depend on the limitations imposed by physics, which in turn depend on the amount of integration available. In order to process the target frequency band, the proposed device is provided with a parallel array of Helmholtz resonators, in other words, an array positioned on the same vertical row in the direction of propagation of the wave. Based on an optimization process, the dimensions of some resonators in the same row are different from other resonators in order to attenuate the waves over the target frequency band.

[0009] The treatment of sound waves of a first frequency within the target frequency band is the purpose of a first resonator of a given size in the row, while the treatment of sound waves of another frequency different from the first frequency and within the target frequency band is the purpose of other resonators of different sizes in the same row. Thus, the acoustic treatment device developed according to the invention makes it possible to reduce the perception of a larger frequency bandwidth by the driver and / or passengers both outside the vehicle and inside the vehicle.

[0010] The resonators may in particular be Helmholtz resonators. In the acoustic treatment device of the invention, the resonators are arranged in one or more rows around the pipe, and according to the invention such a feature may be applied to one or each of the rows: the resonators in one and the same row have different dimensions from one resonator to the next.

[0011] In this case, a "row" is understood to mean that the resonators are arranged one after another around the cross section of the pipe, as seen in a plane perpendicular to the axis of elongation of the pipe, which axis of elongation defines the direction of propagation of the sound waves. In other words, the resonators of one and the same row are arranged so that one and the same plane extending perpendicularly to the axis of elongation of the pipe or to the axis of propagation of the sound waves passes through them.

[0012] Furthermore, the term "a given dimension" of a resonator is in particular a selected reference dimension of said resonator, and a "corresponding dimension" corresponds to the given dimension of said resonator measured on another resonator in the same row. It should be understood that, for example, if the length of the cavity of one resonator is chosen to be a given dimension and the corresponding dimension on another resonator is the length of the cavity of said other resonator, then these two lengths will differ from each other.

[0013] Furthermore, in the sense of the present invention, two dimensions are different because they go beyond simple deviations from one resonator to another due to manufacturing tolerances. A dimension difference between one resonator and another within the same row is considered to exist if such a difference has an effect on the acoustic processing of waves over a frequency range of about 3 to 4 Hz, as determined by one feature of the present invention.

[0014] According to an optional feature of the invention, the given dimension corresponds to a height of the cavity measured along a direction parallel to the axis of extension of the neck.

[0015] According to another optional feature of the invention, the given dimension corresponds to the width of the cavity measured along a direction perpendicular to the axis of elongation of the tube and the axis of extension of the neck.

[0016] According to another optional feature of the invention, the given dimension corresponds to a length of the lumen measured along a direction parallel to the axis of elongation of the conduit.

[0017] According to another optional feature of the invention, the given dimension corresponds to the height of the neck measured along a direction parallel to the axis of extension of the neck.

[0018] According to another optional feature of the invention, the dimension corresponds to the radius of the neck measured along a direction perpendicular to the axis of extension of the neck.

[0019] According to another optional feature of the invention, at least one resonator in a row of resonators has a given dimension that is the same as the corresponding dimension of its adjacent resonator.It will be appreciated that resonators within the same row are not all different from each other.

[0020] According to another optional feature of the invention, the resonator row comprises a first subgroup of resonators having a first value for a given dimension and at least a second subgroup of resonators having a second value for the given dimension different from the first value, the first subgroup of resonators being arranged on a first portion of the acoustic treatment device and the second subgroup of resonators being arranged on a second portion of the acoustic treatment device different from the first portion. It will be understood that the resonators of the same given dimension in the resonator row are arranged one after another around the pipe.

[0021] According to another optional feature of the invention, the row of resonators comprises a first subset of resonators having a first value for a given dimension and at least one second subset of resonators having a second value for the given dimension different from the first value, the resonators in the first subset of resonators alternating with the resonators in the second subset of resonators.

[0022] According to another optional feature of the invention, at least a neck portion of one resonator in the row of resonators is offset along the axis of elongation from neck portions of other resonators in the row of resonators.

[0023] Here, the concept of axial offset of the necks of the resonators in the same row should be understood to mean that the position along the elongation axis of one of the necks associated with the resonators of the determined row is different from the position along the elongation axis of the other neck associated with another resonator in the row. This different position reflects a determined offset of the theoretical position of the necks, so it should be understood that the axial offset between the two necks of the two resonators of the same row according to the invention is greater than the minimum offset due to the manufacturing tolerances of each neck. The axial offset between the two necks of the two resonators of the same row makes it possible to optimize the acoustic treatment by implementing the interference phenomenon of the plane wave field.

[0024] According to an optional feature of the invention, the row of resonators comprises at least one first subset of resonators and at least one second subset of resonators, a first plane perpendicular to the axis of elongation passes through the neck of the first subset of resonators, a second plane perpendicular to the axis of elongation passes through the neck of the second subset of resonators, the first plane and the second plane being different from each other. It should be understood that the cavities of the resonators in the row are centered relative to each other and only the necks of some of the resonators, namely those forming the first subset. In other words, the system according to the invention actually comprises the same row of resonators, wherein the necks of the subset of resonators are offset from the center.

[0025] According to another optional feature of the invention, the resonators of the first subset are arranged one after the other and the resonators of the second subset are arranged one after the other.

[0026] According to another optional feature of the present invention, the duct leads to an airflow inlet opening and an airflow outlet opening, the necks of the resonators in the first subset of resonators are arranged closer to the duct inlet opening than to the duct outlet opening, and the necks of the resonators in the second subset of resonators are arranged closer to the duct outlet opening than to the duct inlet opening.

[0027] According to another optional feature of the invention, the resonators of the first subset are arranged on a first wall surface opposite a second wall surface on which the resonators of the second subset are arranged.

[0028] According to another optional feature of the invention, resonators of the first subset alternate with resonators of the second subset.

[0029] The invention also relates to a vehicle front end module intended to interact with a vehicle heating, ventilation and air conditioning system, the front end module comprising: at least one airflow guide device, the airflow guide device helping to define a duct through which the airflow flows; a ventilator capable of causing the airflow to flow through the guide device; a heat exchanger across the guide device; and an acoustic treatment device according to any of the above features. It should be understood here that the acoustic treatment device forms all or part of the guide device, and the duct of the acoustic treatment device and the duct of the guide device are continuous. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other characteristics, details and advantages of the invention will become more apparent on reading the following description and on studying several exemplary embodiments given by way of non-limiting indication, with reference to the accompanying drawings, in which:

[0031] Figure 1 is a schematic diagram of the front end of a motor vehicle equipped with a front end module in which an acoustic treatment device according to the present invention is installed;

[0032] Figure 2 is a perspective view of a first embodiment of an acoustic processing device according to the present invention;

[0033] Figure 3 yes Figure 2 a perspective view of a resonator and duct of an acoustic treatment device shown, with one wall of the acoustic treatment device removed to make the resonator visible;

[0034] Figure 4 yes Figure 3 A cross-sectional view of the acoustic treatment device shown;

[0035] Figure 5 is a cross-sectional view of a variation of the acoustic treatment device;

[0036] Figure 6 It shows that for a sound wave with a frequency of 490 Hz and a sound wave with a frequency of 900 Hz, Figure 3 A graph showing the reduction in acoustic energy achieved by an acoustic treatment device in FIG.

[0037] Figure 7 is able to Figure 3 A diagram comparing the effect of the acoustic treatment device of on the one hand and the effect of two acoustic treatment devices of the prior art on the other hand, Figure 3 The acoustic processing device is capable of acoustically processing a wave having a first frequency of 292 Hz and a wave having a second frequency of 584 Hz, and each of the two acoustic processing devices in the prior art processes the wave having the first frequency and the wave having the second frequency, respectively;

[0038] Figure 8is a schematic diagram of a variant embodiment of the invention, more specifically of a face of a wall delimiting a duct into which the resonators open, showing the axial offset of the resonators within the same row;

[0039] Fig. 9 yes Figure 8 A longitudinal cross-sectional view of a variation of the acoustic treatment device shown;

[0040] Fig.10 It shows that for a sound wave with a frequency of 292 Hz and a sound wave with a frequency of 584 Hz, Figure 8 Figure 2. A graph of the sound energy reduction achieved by the acoustic treatment device in FIG. DETAILED DESCRIPTION

[0041] The features, variants and various embodiments of the present invention may be combined with each other in various combinations, as long as they are not mutually incompatible or mutually exclusive. In particular, it is conceivable that the variant of the present invention only includes a selection of the following features separated from the other features described, if this selection of features is sufficient to confer technical advantages and / or distinguish the present invention from the prior art.

[0042] In the drawings, elements common to several figures retain the same reference numerals.

[0043] In the detailed description that follows, the terms "longitudinal", "transverse" and "vertical" refer to the orientation of the acoustic treatment device according to the invention. The longitudinal direction corresponds to the main flow direction of the airflow through the acoustic treatment device and the elongation axis of the duct of the acoustic treatment device, which is parallel to the longitudinal axis L of the orthogonal coordinate system L, V, T shown in the figure. The transverse direction and the vertical direction correspond to directions perpendicular to the longitudinal direction, parallel to the transverse axis T and the vertical axis V of the coordinate system L, V, T, respectively.

[0044] Figure 1 An acoustic treatment device 1 according to the present invention is shown, which is configured to be installed in a front-end module 100 of a vehicle 101. Such a front-end module 100 includes, for example: at least one airflow guiding device 102, which helps to define a duct 2 through which the airflow flows; a ventilator 104 capable of causing the airflow to flow through the guiding device; a heat exchanger 106 for the airflow flowing through the guiding device; and an acoustic treatment device 1 according to the present invention. More specifically, the ventilator causes the airflow to flow through the device from the external environment of the vehicle via the guiding device, and the heat exchanger is installed across the duct 2 and is configured to be able to cool a liquid that also flows in the exchanger in order to cool a battery pack in another area of ​​the vehicle.

[0045] The use of the ventilator generates sound waves of different frequencies, which propagate through the front end module. The acoustic treatment device 1 is configured to attenuate the acoustic energy of the sound waves, which can be perceived from outside the vehicle and / or by a user of the vehicle. The acoustic treatment device 1 can be arranged in particular at the inlet of the front end module, in particular the air intake opening 108, or at the outlet of the front end module, in particular the blower opening 110.

[0046] Regardless of the position of the acoustic treatment device 1 relative to the guide device, the acoustic treatment device 1 helps to define the duct 2 through which the airflow flows. More specifically, if Figure 2 As shown, the acoustic treatment device 1 includes at least one wall 4, and more specifically, an interior face 6, which helps to at least partially define a duct 2 through which an airflow can flow.

[0047] The inner face 6 of the wall 4 is configured such that it delimits the duct 2 about an axis of elongation A extending parallel to the flow direction of the gas stream through the duct 2 .

[0048] More specifically, the wall 4 comprises four parts, including two transverse parts 10 and two vertical parts 8, the two vertical parts 8 respectively extending in a plane substantially perpendicular to the plane in which the transverse parts 10 are located, the internal faces of the wall being defined by successive internal faces of different parts. These parts are arranged so that the cross section of the duct 2 delimited by the wall 4, as seen in a plane perpendicular to the axis of elongation A, has a rectangular overall shape delimited laterally by the internal faces 6 of the transverse parts 10 and vertically by the internal faces 6 of the vertical parts 8. It is also possible to define an inlet 12 of the duct 2 and an outlet 14 of said duct 2, which define the longitudinal dimension of the duct 2 passing through the acoustic treatment device 1. The terms "inlet" and "outlet" are chosen in particular with respect to the flow direction of the airflow through the duct 2.

[0049] In order to treat the acoustic energy of the pipe 2 passing through the acoustic treatment device 1, the acoustic treatment device 1 comprises at least one array of resonators 16, which is formed by one or more rows 18 of resonators 16 arranged in the wall 4 around the pipe 2. Each resonator 16 in the row 18 of resonators 16 comprises at least a cavity 20 arranged in the wall 4 and a neck 22 connecting the cavity 20 to the pipe 2. The resonators 16 are advantageously Helmholtz resonators. As mentioned above, the resonators are arranged in one and the same row 18 if they are arranged around the same cross section of the pipe 2 when viewed in a plane perpendicular to the axis of elongation A, that is, if one and the same plane (in this case the transverse and vertical plane) passes through each of these resonators. The various figures of the present application show an acoustic treatment device in an application with a small space requirement, in this case a front-end module, which includes the presence of a single row of resonators. However, the following description also applies to acoustic treatment devices with multiple rows of resonators, if at least one row has the features to be described.

[0050] As mentioned above, Figures 3 to 5 , 8 and 9, each resonator comprises a cavity 20 and a neck 22 connecting the cavity 20 to the pipe 2, the resonators being visible in these figures because the wall delimiting the pipe 2 is hidden. More specifically, the wall 4 has a thickness measured along a direction perpendicular to the axis of elongation A between an internal face 6 of the wall 4 facing the pipe and an opposite external face 24, and the cavity 20 is arranged in the thickness of the wall 4. The neck 22 of each resonator 16 also extends in the thickness of the wall 4, opening on one side to the cavity 20 and on the other side to the pipe 2.

[0051] The cavity 20 has, in the wall 4 , the general shape of a parallelepiped, with a substantially rectangular cross section when viewed in a plane perpendicular to the axis of elongation A. The neck 22 has, between the cavity 20 and the duct 2 , the general shape of a cylinder of circular cross section.

[0052] According to the invention, at least for a given dimension D of the cavity 20 or of the neck 22, the value of the dimension D of one or more resonators 16 in a row 18 differs from the value of the corresponding dimension D of at least one other resonator 16 in the same row 18. The difference in the value of the dimension D from one resonator to another within the same row 18 makes it possible to process sound waves with two different frequencies, for example, sound waves with a first frequency are mainly processed by a resonator 16 with a given dimension, while sound waves with a second frequency different from the first frequency are mainly processed by a resonator 16 with a different dimension. Thus, the acoustic treatment device 1 developed according to the invention makes it possible to reduce the perception of a greater range of wave frequencies by the driver and / or passengers located in the interior of the vehicle.

[0053] Furthermore, at least one resonator 16 in a row 18 of resonators 16 has a given dimension D that is the same as the corresponding dimension D of its adjacent resonator 16. It will be appreciated that, at least with respect to the given dimension D, the resonators 16 within one and the same row 18 are not all different from one another.

[0054] Thus, a row 18 of resonators 16 may be defined to include a first subset 26 of resonators 16 having a first value for a given dimension D and at least a second subset 28 of resonators 16 having a second value different from the first value for the given dimension D. More generally, in accordance with the present invention, resonators 16 may be grouped into a defined number of subsets for handling acoustic energy of the defined number of different propagation frequencies.

[0055] With regard to the dimension D mentioned earlier in the description, the term "given dimension D" of a resonator 16 is in particular a selected reference dimension D of said resonator 16, and a "corresponding dimension D" corresponds to the given dimension D of said resonator 16 measured on another resonator 16 in the same row 18. It should be understood that, for example, if the length D2 of the cavity 20 of a resonator 16 is selected as the given dimension D, and the corresponding dimension D on another resonator 16 is the length D2 of the cavity 20 of said other resonator 16, the two lengths D2 will be different from each other.

[0056] A given dimension D may be selected from the following non-exhaustive list: height D1 of cavity 20 , length D2 of cavity 20 , width D3 of cavity 20 , height D4 of neck 22 and / or radius D5 of neck 22 .

[0057] The height D1 of the cavity 20 corresponds to the maximum extent of the cavity 20 measured along a direction parallel to the axis of extension of the neck 22 .

[0058] The length D2 of the cavity 20 corresponds to the maximum extent of the cavity 20 measured along a direction parallel to the axis of elongation A of the pipe 2 .

[0059] The width D3 of the cavity 20 corresponds to the maximum extent of the cavity 20 measured along a direction perpendicular to the axis of elongation A of the pipe 2 and to the axis of extension of the neck 22 .

[0060] The height D4 of the neck 22 corresponds to the maximum extent of the neck 22 measured along a direction parallel to the axis of extension of the neck 22 , between the point at which the neck 22 opens into the cavity 20 and the point at which the neck 22 opens into the duct 2 .

[0061] The radius D5 of the neck 22 corresponds to half of the maximum extent measured along a direction perpendicular to the axis of extension of the neck 22 .

[0062] For example, the acoustic processing device according to the present invention can be configured so that the first subset 26 of resonators 16 can process sound waves in the frequency range between 400 Hz and 500 Hz, for example 450 Hz, and the second subset 28 of resonators 16 can process sound waves in the frequency range between 850 Hz and 950 Hz, for example 900 Hz.

[0063] In another test, the inventors were able to verify the effectiveness of the device, wherein a distinction could be made between a first subset 26 of resonators 16 sized to handle sound waves in a frequency range between 250 Hz and 300 Hz, for example 292 Hz, and a second subset 28 of resonators 16 sized to handle sound waves in a frequency range between 550 Hz and 600 Hz, for example 584 Hz.

[0064] A more detailed description will now be given of an exemplary embodiment in which the resonators 16 of the first subset 26 are sized to acoustically process sound waves having a frequency of 450 Hz and in which the resonators 16 of the second subset 28 are sized to acoustically process sound waves having a frequency of 900 Hz.

[0065] In the remaining description, descriptions of features of one resonator 16 of the first subset 26 may apply to all resonators 16 of the first subset 26. Equivalently, descriptions of features of one resonator 16 of the second subset 28 may apply to all resonators 16 of the second subset 28.

[0066] In this case, the length D2 of the resonators 16 of the first subset 26 and of the resonators 16 of the second subset 28 is identical and equal to 80.0 mm.

[0067] In this particular example, the cavities 20 of the resonators 16 of the first subset 26 have a first height D11 ranging between 22.0 mm and 24.5 mm. More specifically, the first height D11 of the cavities 20 of the resonators 16 of the first subset 26 is 23.5 mm.

[0068] Furthermore, the cavities 20 of the resonators 16 of the first subset 26 have a first width D31 ranging between 30.0 mm and 33.5 mm. More specifically, the first width D31 of the cavities 20 of the resonators 16 of the first subset 26 is 31.7 mm.

[0069] The necks 22 of the resonators 16 of the first subset 26 also have a first height D41 ranging between 1.9 mm and 2.1 mm. More specifically, the first height D41 of the necks 22 of the resonators 16 of the first subset 26 is 2.0 mm.

[0070] Finally, the necks 22 of the resonators 16 of the first subset 26 have a first radius R51 ranging between 9.0 mm and 10 mm. More specifically, the first radius R51 of the necks 22 of the resonators 16 of the first subset 26 is 9.5 mm.

[0071] The dimensions of the resonators 16 of the second subset 28 are different in that the cavities 20 have a second width D12 ranging between 34.5 mm and 38.0 mm. More specifically, the second height D12 of the cavities 20 of the resonators 16 of the second subset 28 is 36.3 mm.

[0072] Furthermore, the cavities 20 of the resonators 16 of the second subset 28 have a second width D32 ranging between 47.5 mm and 52.5 mm. More specifically, the second width D32 of the cavities 20 of the resonators 16 of the second subset 28 is 50.0 mm.

[0073] The necks 22 of the resonators 16 of the second subset 28 also have a second height D42 ranging between 16.0 mm and 18.0 mm. More specifically, the second height D42 of the necks 22 of the resonators 16 of the second subset 28 is 17.0 mm.

[0074] Finally, the necks 22 of the resonators 16 of the second subset 28 have a second radius D52 ranging between 9.5 mm and 10.5 mm. More specifically, the second radius D52 of the necks 22 of the resonators 16 of the second subset 28 is 10.0 mm.

[0075] like Figure 6 As shown, the graph reflects the amount of attenuated acoustic energy according to the frequency of the sound waves in the pipe equipped with the acoustic treatment device, the amount of attenuated acoustic energy being defined by the ratio between the amount of energy as input and the amount of energy as output, the size of the resonators 16 of the first subgroup 26 makes it possible to attenuate sound waves with a frequency of 450 Hz, particularly in this case, by reducing the acoustic energy of these waves propagating in the pipe by approximately 17 dB, while the size of the resonators 16 of the second subgroup 28 makes it possible to attenuate sound waves with a frequency of 900 Hz, particularly in this case, by reducing the acoustic energy of these waves propagating in the pipe by approximately 22 dB.

[0076] The presence of a first subgroup 26 of resonators 16 and a second subgroup 28 of resonators 16 around the pipe 2 makes it possible to treat sound waves of a first frequency and sound waves of a second frequency. The inventors have been able to note that this combined acoustic treatment makes it possible to effectively treat sound waves of two different frequencies without adversely affecting the effectiveness of the acoustic treatment of each specific frequency. For example, Figure 7A solid line is used to illustrate the amount of acoustic energy reduced using an acoustic treatment device according to the present invention, which is configured to process a sound wave having a first frequency of 292 Hz and a sound wave having a second frequency of 584 Hz in combination. It is noteworthy that in this figure, a device specifically configured to process sound waves having this first frequency enables a greater reduction in sound level, as shown by the dashed line, and a device specifically configured to process sound waves having this second frequency enables a greater reduction in sound level, as shown by the dotted line, but the inventors have noted that the maximum performance reduction for each frequency is advantageously compensated by the advantage of being able to effectively process a wide range of frequencies using the same acoustic treatment device.

[0077] exist Figure 3 and 4 In the example shown, resonators 16 of the same given dimension D in a row 18 of resonators 16 are arranged one after another around the duct 2. Thus, a first subgroup 26 of resonators 16 is arranged on a first portion of the acoustic treatment device 1, while a second subgroup 28 of resonators 16 is arranged on a second portion of the acoustic treatment device 1 different from the first portion. More specifically, in this example, the first subgroup 26 is arranged on one of the vertical portions 8 and one of the transverse portions 10 of the wall 4, while the second subgroup 28 is arranged on another vertical portion 8 and another transverse portion 10 of the wall 4.

[0078] according to Figure 5 In the alternative example of the invention shown, the resonators 16 of the first subset 26 of resonators 16 alternate with the resonators 16 of the second subset 28 of resonators 16. It should be understood that the resonators 16 of the first subset 26 and the resonators 16 of the second subset 28 are arranged on each of the vertical portion 8 and the transverse portion 10 of the wall 4 so that at least one resonator 16 of the first subset 26 is framed by two resonators 16 of the second subset 28, and at least one resonator 16 of the second subset 28 is framed by two resonators 16 of the first subset 26.

[0079] Different functions that can be implemented in addition to what has just been described will now be described.In addition to the different sizes, the resonators 16 in the same row may also differ in their axial position within the pipe.

[0080] like Figure 8 and 9 As shown, at least the neck 22 of one resonator 16 in the row 18 of resonators 16 is axially offset by a distance d along the elongation axis A from the necks 22 of the other resonators 16 in the same row 18. The longitudinal axial offset of the neck 22 of at least one of the resonators 16 relative to the necks 22 of the other resonators 16 in the row 18 makes it possible to increase the reduction of the noise level by exploiting the phenomenon of phase interference (assuming a plane wave field) while reducing the space requirements.

[0081] In other words, the position of one of the necks 22 along the axis of elongation A is different from the position of the other neck 22 along the axis of elongation A. To this end, at least one neck 22 in the row 18 of resonators 16 is closer to the inlet opening 12 of the pipe 2 than to the outlet opening 14 and / or at least one other neck 22 of the row 18 of resonators 16 is closer to the outlet opening 14 than to the inlet opening 12 of the pipe 2.

[0082] Thus, it is possible to define a row 18 of resonators 16 comprising at least a first subset 30 and a second subset 32 ​​of resonators 16, a first plane perpendicular to the axis of elongation A passing through the necks 22 of the resonators of the first subset 30, a second plane perpendicular to the axis of elongation A passing through the necks 22 of the resonators of the second subset 32, the first plane and the second plane being different from each other. It will be understood that the necks 22 of the resonators 16 of the first subset 30 are aligned with each other by being located in the first plane, while the necks 22 of the resonators 16 of the second subset 32 ​​are aligned with each other by being located in the second plane.

[0083] exist Figure 8 and Fig. 9 In the example shown, the neck 22 of the resonator 16 of the first subset 30 is arranged closer to the inlet opening 12 of the pipe 2 than to the outlet opening 14 of the pipe 2, and the neck 22 of the resonator 16 of the second subset 32 ​​is arranged closer to the outlet opening 14 of the pipe 2 than to the inlet opening 12 of the pipe 2.

[0084] The distance d measured along a direction parallel to the elongation axis A between the neck 22 of a resonator 16 of the first subset 30 and the neck 22 of a resonator 16 of the second subset 32 ​​is between 30 mm and 80 mm. In this case, the distance is measured along a direction parallel to the elongation axis A between a straight line perpendicular to the elongation axis A and passing through the centers of the two necks 22. For example, such a distance measured between the neck 22 of a resonator 16 of the first subset 30 and the neck 22 of a resonator 16 of the second subset 32 ​​may be about 46 mm or about 60 mm. The distance may depend on the dimensional characteristics of the resonators 16 in the row and / or the frequency of the acoustic waves to be processed.

[0085] Fig.10The acoustic gain that may be achieved according to the configuration just described is schematically shown, i.e. the axial offset of some necks of the resonators relative to other necks of the same row of resonators. The inventors were able to determine by calculation that for a resonator arranged in a front-end module and configured to process acoustic waves with a frequency of 292 Hz, the distance d between two subsets of resonators may advantageously be equal to 60 mm, and for a resonator arranged in a front-end module and configured to process acoustic waves with a frequency of 584 Hz, the distance d between two subsets of resonators may advantageously be equal to 46 mm. Fig.10 It is shown that for each of these distances d and the corresponding frequency of the processed sound wave, the sound energy can be reduced by about 20% to 30%. It should be understood that for other sound wave frequencies, the inventors will mathematically determine the distance d so that it is optimal and minimizes the transmitted sound energy to avoid it being perceived by the user of the vehicle and from the outside of the vehicle.

[0086] exist Figure 8 and Figure 2 In the first configuration shown, the resonators 16 of the first subset 30 alternate with the resonators 16 of the second subset 32. In other words, at least one resonator 16 of the first subset 30 is framed by two resonators 16 of the second subset 32, and at least one resonator 16 of the second subset 32 ​​is framed by two resonators 16 of the first subset 30.

[0087] As an alternative, Fig. 9 As shown, the resonators 16 of the first subset 30 can be arranged one after another, while the resonators 16 of the second subset 32 ​​can be arranged one after another. In the example shown, the resonators 16 of the first subset 30 are arranged one after another by being arranged on one of the vertical portions 8, while the resonators 16 of the second subset 32 ​​are arranged one after another on the other vertical portion 8, but it should be understood that the resonators 16 of the first subset 30 can also extend on one of the lateral portions 10, while the resonators 16 of the second subset 32 ​​can extend on the other lateral portion 10.

[0088] In a variant not shown here, the acoustic treatment device 1 according to the invention can be configured so that the resonators 16 in one and the same row 18 are divided into a first subgroup 26 and a second subgroup 28, as previously described in the description, and into a first subset 30 and a second subset 32, as described above. It should be understood that the same resonator 16 is a member of a subgroup and a subset. Thus, the resonator 16 can be a member of the first subgroup 26 and the first subset 30 or the second subset 32, or a member of the second subgroup 28 and the first subset 30 or the second subset 32.

[0089] The invention just described by means of several embodiments makes it possible to achieve its stated purpose, namely to optimize the reduction of the acoustic energy transmitted and perceptible by the user of the motor vehicle and from outside the vehicle, in the application of an acoustic treatment device with resonators arranged in an environment with reduced space requirements. Resonators of different sizes within the same row of resonators advantageously make it possible to increase the range of sound wave frequencies that can be effectively treated by the acoustic treatment device and to realize an acoustic treatment device with a reduced number of rows of resonators.

[0090] However, the invention is not limited to the devices and configurations described and shown here, and it also extends to any equivalent devices and configurations and any technically feasible combination of these devices. In particular, the examples of the size and distribution of the resonators 16 in the acoustic treatment device 1 are given in an indicative manner and do not limit the invention.

Claims

1. An acoustic treatment device (1) for installation in a vehicle cooling system, the acoustic treatment device (1) comprising at least one wall (4) which helps to define a duct (2) for airflow, the duct (2) being arranged about an elongated axis (A) parallel to the flow direction of the airflow through the duct (2), the acoustic treatment device (1) comprising at least one resonator (16) array, the at least one resonator array being formed by one or more rows (18) of resonators (16) arranged around the duct (2), each resonator (16) in a row (18) of resonators (16) comprising at least a cavity (20) arranged in the wall (4) and a neck (22) connecting the cavity (20) to the duct (2), characterized in that At least for a given dimension (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) of the cavity (20) or the neck (22), at least one resonator (16) in the row (18) has a different value than the corresponding dimension of the other resonators (16) in the row (18).

2. The acoustic treatment device (1) according to the preceding claim, wherein: The given dimensions (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) correspond to the height (D1, D11, D12) of the cavity (20) measured along a direction parallel to the extension axis of the neck (22).

3. The acoustic processing device (1) according to any one of the preceding claims, wherein: The given dimensions (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) correspond to the widths (D3, D31, D32) of the cavity (20), the widths being measured along a direction perpendicular to the elongation axis (A) of the pipe (2) and the extension axis of the neck (22).

4. The acoustic treatment device (1) according to any one of the preceding claims, wherein: The given dimensions (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) correspond to the height (D4, D41, D42) of the neck (22) measured along a direction parallel to the extension axis of the neck (22).

5. The acoustic treatment device (1) according to any one of the preceding claims, wherein: The dimensions (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) correspond to the radius (D5, D51, D52) of the neck (22) measured along a direction perpendicular to the extension axis of the neck (22).

6. The acoustic processing device (1) according to any one of the preceding claims, wherein: The row (18) of resonators (16) includes a first subset (26) of resonators (16) having a first value for a given dimension (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) and at least a second subset (28) of resonators (16) having a second value for the given dimension (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) different from the first value, the first subset (26) of resonators (16) being disposed on a first portion of the acoustic treatment device (1) and the second subset (28) of resonators (16) being disposed on a second portion of the acoustic treatment device (1) different from the first portion.

7. The acoustic processing device (1) according to any one of claims 1 to 5, wherein: The row (18) of resonators (16) comprises a first subset (26) of resonators (16) having a first value for a given dimension (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) and at least one second subset (28) of resonators (16) having a second value for the given dimension (D, D1, D11, D12, D2, D3, D31, D32, D4, D41, D42, D5, D51, D52) different from the first value, the resonators (16) in the first subset (26) of resonators (16) alternating with the resonators (16) in the second subset (28) of resonators (16).

8. The acoustic treatment device (1) according to any one of the preceding claims, wherein: At least a neck portion (22) of one resonator (16) in a row (18) of resonators (16) is offset along an axis of elongation (A) from the neck portions (22) of other resonators (16) in the row (18) of resonators (16).

9. A vehicle front end module for interacting with a vehicle cooling system, the front end module comprising: at least one airflow guiding device, the airflow guiding device helping to define a duct (2) through which the airflow flows; a ventilator capable of causing the airflow to flow through the guiding device; A heat exchanger arranged across the guide means; and an acoustic treatment device (1) as claimed in any one of the preceding claims.

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