Acoustic attenuation device

Abstract

A sound attenuation device configured for mounting on a motor vehicle air intake, said device comprising: at least one airflow duct for channeling said airflow along a flow direction within the duct, said duct being delimited by at least one wall; at least one sound attenuation element disposed at least partially on said wall of the duct, said sound attenuation element comprising a cavity and a neck connecting said cavity to said airflow duct, said neck extending along a principal axis parallel to the airflow direction within the airflow duct. (Shorthand figure: Fig. 2)

Description

Title of the invention: Acoustic attenuation device

[0001] The subject of the invention is a sound attenuation device configured to be mounted in a ventilation, heating and / or air conditioning installation of a motor vehicle which comprises such a sound attenuation device or in a front panel module of a motor vehicle which comprises the sound attenuation device, as well as a ventilation, heating and / or air conditioning installation of a motor vehicle which comprises such a sound attenuation device and a front panel module of a motor vehicle which comprises the sound attenuation device.

[0002] Generally, a motor vehicle comprises an air inlet in the form of an opening located on the front face of said motor vehicle. The incoming air is used to enable heat exchange between it and the cooling system of the motor vehicle, said cooling system being located near the front face of said vehicle. More specifically, the air entering the engine compartment of the motor vehicle is guided by ducts to the cooling system of said motor vehicle to enable heat exchange between the incoming air and the heat exchanger of the cooling system. It is important to minimize losses of air flow between the air inlet and the heat exchanger.In fact, any air flow entering the interior of the vehicle, and escaping towards the engine compartment before having contributed to the heat exchange inside the motor vehicle, negatively influences the air resistance coefficient of said motor vehicle.

[0003] It is known to use air guides in the form of a duct generally made of plastic or other flexible material connecting the air inlet to the cooling system. When air circulates within this duct, in particular when the motor-fan unit of the cooling system is activated to ensure the cooling of the batteries in the case of an electric vehicle, noise pollution is generated. Such a duct ensures the flow and distribution of an air flow. Noise pollution is generated in such ducts, in fact, the acoustic waves generated by the motor-fan unit propagate along the air duct and radiate towards the front of the vehicle.

[0004] To overcome this, it is known to equip these air circulation ducts with at least one acoustic attenuation member in order to reduce the acoustic energy which is propagated and thus reduce the noise radiated at the outlet of these ducts, in particular when charging an electric vehicle. To allow a reduction in acoustic waves, this type of acoustic attenuation member comprises a resonator of Helmholtz to reduce the acoustic energy radiated at the front of the vehicle at a given frequency.

[0005] A Helmholtz resonator comprises, in a known manner, a cavity and a neck connecting the cavity to an air duct oriented perpendicular to the direction of air flow. The interaction between the air flow and the neck of the resonator can cause acoustic disturbances and generate secondary noises, in particular whistling, which degrade the performance of the acoustic attenuation device comprising resonators. The resonator then loses efficiency, or even generates noise.

[0006] In this context, the present invention proposes an acoustic attenuation device in which the generation of acoustic waves, causing in particular whistling sounds, linked to the interaction between the air flow and acoustic attenuation members arranged in the duct are reduced or avoided.

[0007] The invention relates to an acoustic attenuation device configured to be mounted on an air intake of a motor vehicle, said device comprising: - at least one air flow duct intended to channel said air flow along a flow direction of said air flow in the air flow duct, said duct being delimited by at least one wall, - at least one acoustic attenuation member arranged at least partly on said wall of the air flow duct, said acoustic attenuation member comprising a cavity and a neck connecting said cavity to said air flow duct, said neck extending along a main extension axis parallel to the direction of the air flow in the air flow duct.

[0008] Thus, the air flow is not directed directly onto the neck of the acoustic attenuation member, which makes it possible to reduce the disturbances and therefore the whistling caused by the shearing of the air on said neck.

[0009] According to one aspect of the invention, the acoustic attenuation member is a Helmholtz resonator.

[0010] According to one aspect of the invention, the neck of the acoustic attenuation member opens into the air flow duct by forming an opening in said air flow duct.

[0011] According to one aspect of the invention, the neck has a circular or polygonal section, in particular rectangular.

[0012] According to one aspect of the invention, the diameter of the neck is between two and a half millimeters and thirty millimeters.

[0013] According to one aspect of the invention, the neck has a height measured along a main extension axis of the neck, the height of the neck being between one millimeter and twenty-five millimeters.

[0014] According to one aspect of the invention, the cavity comprises at least four faces, the neck being arranged on one of the faces.

[0015] According to one aspect of the invention, at least one cavity of the network of acoustic attenuation members has a parallelepiped shape.

[0016] According to one aspect of the invention, the cavity of the acoustic attenuation member has a rectangular section.

[0017] According to another optional characteristic of the invention, the network of acoustic attenuation members extends over at least two, preferably at least three, preferably at least four walls of the air flow duct.

[0018] According to one aspect of the invention, the neck has an end section adjacent to the opening formed by the neck opening into the air flow duct, said section also being called the downstream section in the present description.

[0019] According to one aspect of the invention, the device comprises a network of acoustic attenuation members.

[0020] According to one aspect of the invention, the network of acoustic attenuation members is organized in the form of a matrix comprising at least two rows of acoustic attenuation members, and where the acoustic attenuation members of the at least two rows are respectively aligned along the direction of air flow. It is understood that each acoustic attenuation member of one of the two rows of said acoustic attenuation members is aligned with at least one acoustic attenuation member of the other of the two rows of acoustic attenuation members, along a direction perpendicular to the direction of air flow.

[0021] According to one aspect of the invention, at least one dimension of the cavity or neck of at least one acoustic attenuation member of a row of the network has a value different from the value of the corresponding dimension of the other acoustic attenuation members of the row. Thus, the acoustic attenuation members are dimensioned so as to process noises of different acoustic frequencies and / or the same noise at different temperatures of the air flow.

[0022] According to one aspect of the invention, the airflow flow duct comprises an air inlet through which the airflow enters and an air outlet through which the airflow exits.

[0023] In one aspect of the invention, the neck of the at least one acoustic attenuation member faces the air outlet of the air flow duct. In other words, the neck of the at least one acoustic attenuation member is oriented in a direction opposite to the air inlet. In other words, the neck of the attenuation member acoustic does not face the airflow circulating in the airflow duct.

[0024] According to one aspect of the invention, the airflow flow duct comprises at least one bottom wall and at least one top wall, the top wall being arranged above the bottom wall when the sound attenuation device is mounted on the vehicle and the bottom wall corresponding to the bottom wall when the sound attenuation device is mounted on the vehicle, at least one sound attenuation member being arranged on the bottom wall of the airflow flow duct and at least one sound attenuation member being arranged on the top wall of the airflow flow duct, a section for the airflow being formed between the neck of the at least one sound attenuation member arranged on the top wall of the airflow flow duct and the neck of the at least one sound attenuation member arranged on the bottom wall of the airflow flow duct.In one aspect of the invention, the neck of the at least one acoustic attenuation member disposed on the lower wall of the air flow duct and the neck of the at least one acoustic attenuation member disposed on the upper wall of the air flow duct are disposed downstream of the section formed by said necks in the direction of flow of the air flow. In other words, the necks of the acoustic attenuation members do not face the air flow.

[0025] According to one aspect of the invention, the air flow duct comprises at least two side walls connecting the lower wall and the upper wall, at least one of the side walls comprising at least one acoustic attenuation member.

[0026] In one aspect of the invention, the at least one acoustic attenuation member is arranged on the air inlet of the air flow duct.

[0027] According to one aspect of the invention, the acoustic attenuation device comprises at least one row of acoustic attenuation members on at least one of the lower and / or upper walls of the air flow duct.

[0028] According to one aspect of the invention, the neck of at least one acoustic attenuation member comprises an upstream section adjacent to the cavity of the acoustic attenuation member and a downstream section adjacent to the opening formed by said neck in the air flow duct.

[0029] According to one aspect of the invention, the downstream section of the neck of the at least one acoustic attenuation member arranged on the lower wall of the air flow duct is separated by a non-zero distance from the downstream section of the neck of the at least one acoustic attenuation member arranged on the upper wall of said air flow duct, the distance extending along an axis parallel to the direction of the air flow. In other words, there is a gap between the passes, particularly between the downstream sections of said passes.

[0030] According to one aspect of the invention, the opening formed by the neck in the airflow flow duct of the at least one acoustic attenuation member arranged on the lower wall of said airflow flow duct is separated by a non-zero distance from the opening formed by the neck of the at least one acoustic attenuation member arranged on the upper wall of said airflow flow duct, the distance extending along an axis parallel to the direction of the airflow. In other words, there is an offset between the openings formed by the necks in the airflow flow duct.

[0031] This makes it possible in particular to maximize the performance of the acoustic attenuation device.

[0032] According to one aspect of the invention, the distance d is between 0 and 80 millimeters.

[0033] Alternatively, the upstream section of the neck of the acoustic attenuation members arranged on the lower wall of the air flow duct is aligned with the upstream section of the neck of the acoustic attenuation members arranged on the upper wall of said air flow duct, along an axis parallel to the direction of the air flow. In other words, there is no offset between the necks along an axis substantially parallel to the direction of the air flow.

[0034] In one aspect of the invention, the acoustic attenuation device is arranged so that the air flow enters through the air inlet of the air flow duct, circulates in the section formed by the acoustic attenuation members arranged on the upper and lower wall of the air flow duct, emerging on the side of the downstream section of said acoustic attenuation members, then heads towards the air outlet of the air flow duct.

[0035] In one aspect of the invention, the acoustic attenuation device comprises at least two acoustic attenuation members on the same wall of the air flow duct, at least one face delimiting the cavity of an acoustic attenuation member being adjacent to a face delimiting the cavity of the other acoustic attenuation member.

[0036] In one aspect of the invention, the acoustic attenuation device comprises on the same wall at least one first acoustic attenuation member comprising a neck and at least one second acoustic attenuation member comprising at least one neck, said second acoustic attenuation member being superimposed on said first acoustic attenuation member.

[0037] In one aspect of the invention, at least one neck of the first acoustic attenuation member and at least one neck of the second acoustic attenuation member of the same wall of the airflow duct are parallel to each other and extend in a substantially parallel direction of the airflow.

[0038] In one aspect of the invention, at least one neck of the first acoustic attenuation member and at least one neck of the second acoustic attenuation member of the same wall of the air flow duct extend in different directions. In other words, the neck of the first acoustic attenuation member extends along a main extension axis of said neck intersecting the extension axis along which the neck of the second acoustic attenuation member extends.

[0039] For example, the neck of the first acoustic attenuation member opens into the air flow duct and at least one neck of the second acoustic attenuation member opens into the cavity of the first acoustic attenuation member.

[0040] In another example, the neck of the first acoustic attenuation member opens into the airflow flow duct and at least one neck of the second acoustic attenuation member also opens into the airflow flow duct.

[0041] In one aspect of the invention, the neck of one of the acoustic attenuation members opens into the cavity of the other acoustic attenuation member, and the neck of the other acoustic attenuation member opens into the airflow flow duct in a direction parallel to the direction of the airflow, the two necks being oriented in different directions.

[0042] In one aspect of the invention, the cavity of the sound attenuating member comprises a high region and a low region, the high region being disposed above the low region when the sound attenuating device is mounted in a vehicle.

[0043] In one aspect of the invention, the neck is adjacent to the upper region of the cavity when the acoustic attenuation member is disposed on the lower wall of the airflow flow duct.

[0044] In one aspect of the invention, the neck is adjacent to the lower region of the cavity when the acoustic attenuation member is disposed on the upper wall of the airflow flow duct.

[0045] Thus, if water has entered the cavity of the acoustic attenuation member arranged on one of the walls, it can easily be evacuated through the neck of said acoustic attenuation member.

[0046] In one aspect of the invention, the lower wall of the airflow flow duct is inclined in a direction different from the main axis of extension of the neck of the acoustic attenuation member opening into the airflow flow duct. In other words, the lower wall of the airflow flow duct extends along a plane intersecting the main axis of extension of the neck.

[0047] In one aspect of the invention, the bottom wall and the top wall of the airflow flow duct are divergent from each other.

[0048] In one aspect of the invention, the necks opening into the airflow flow duct are aligned with each other. In other words, the necks opening into the airflow flow duct are substantially parallel to each other.

[0049] The present invention also relates to a ventilation, heating and / or air conditioning installation for a motor vehicle which comprises an acoustic attenuation device as described in the present document, the acoustic attenuation device being installed at an air outlet or inlet of the ventilation, heating and / or air conditioning installation.

[0050] The present invention also relates to a front panel module of a motor vehicle which comprises an acoustic attenuation device as described in the present document, the acoustic attenuation device being installed at an air inlet on the front panel of the motor vehicle.

[0051] Other characteristics and advantages of the present invention will appear more clearly on reading the following description, provided for illustrative and non-limiting purposes, and the appended drawings in which:

[0052] [Fig-1] [Fig.l] is a schematic representation of an attenuation device acoustics comprising a network of acoustic attenuation devices,

[0053] [Fig.2] [Fig.2] is a schematic representation of an attenuation device acoustics according to a first embodiment,

[0054] [Fig.3] [Fig.3] is a schematic representation of an attenuation device acoustics according to a second embodiment,

[0055] [Fig.4] [Fig.4] is a schematic representation of an attenuation device acoustics according to a third embodiment,

[0056] [Fig.5] [Fig.5] is a schematic representation of an attenuation device acoustics according to a fourth embodiment.

[0057] [Fig.l] represents an acoustic attenuation device 1 comprising a set of walls defining a flow duct for an air flow F arranged for the flow of an air flow F generated by an air inlet. The walls of the air flow flow duct, here in particular the side walls and the upper wall 6, here comprise a plurality of acoustic attenuation members 3b arranged to reduce the noise generated by the air inlet. In this example, a single row of acoustic attenuation members is shown on the upper wall. In an embodiment not shown here, the acoustic attenuation device could comprise a network of acoustic attenuation members arranged on at least one wall of the air flow flow duct comprising several rows, the members acoustic attenuation of the network being distributed at least parallel to the direction of air flow.

[0058] Figures 2 to 6 describe in more detail the different embodiments of the acoustic attenuation device 1 according to the invention.

[0059] In Figures 2 to 6, the flow duct 2 of the air flow F has a lower wall 7 inclined in a direction different from the main axis of extension of the neck A, Ab of the acoustic attenuation member 3a, 3b opening into the flow duct 2 of the air flow F. In other words, the lower wall 7 of the flow duct 2 of the air flow F extends along a plane intersecting the main axis of extension of the neck Aa, Ab. The lower wall 5 and the upper wall 6 of the flow duct 2 of the air flow F are divergent from each other.

[0060] As shown in Figures 2 to 6, the flow duct 2 of the air flow F comprises an air inlet 14 through which the air flow F enters and an air outlet 13 through which the air flow F exits. The air inlet 14 is located upstream of the air outlet 13 in the direction of circulation of the air flow. The acoustic attenuation members 3a, 3b are here arranged on the air inlet 14 of the flow duct 2 of the air flow F. More precisely, the acoustic attenuation members 3a, 3b arranged on the upper 6 and lower 7 walls of the flow duct 2 of the air flow F comprise a cavity 4a, 4b and a neck 5a, 5b connecting said cavity 4a, 4b to said flow duct 2 of the air flow F, said neck 5a, 5b extending along a main extension axis Aa, Ab parallel to the direction of the air flow F in the flow duct 2 of the air flow F.

[0061] The cavity 4a, 4b of the sound attenuating member comprises a high region 8a, 8b and a low region 9a, 9b, the high region 8a, 8b being arranged above the low region 9a, 9b when the sound attenuating device 1 is mounted in a vehicle. The neck 5a is adjacent to the high region 8a of the cavity 4a when the sound attenuating member 3a is arranged on the lower wall 7 of the flow duct 2 of the air flow F, and the neck 3b is adjacent to the low region 9b of the cavity 4b when the sound attenuating member 3b is arranged on the upper wall 6 of the flow duct 2 of the air flow F.

[0062] In the embodiment shown in [Fig. 2], the acoustic attenuation device 1 comprises at least one acoustic attenuation member 3b arranged on the upper wall 6 of the flow duct 2 of the air flow F and at least one acoustic attenuation member 3a arranged on the lower wall 7 of the flow duct 2 of the air flow F. The acoustic attenuation device 1 may comprise, for example, one or more rows (thus forming a network) of acoustic attenuation members on the upper wall and on the lower wall of the flow duct of the air flow. A section S for the air flow, which extends along an axis substantially perpendicular to the direction of the air flow F, is formed between the at least one member attenuation member 3b arranged on the upper wall 6 of the duct 2 and the at least one acoustic attenuation member 3a arranged on the lower wall 7 of the duct 2. The neck 5a of the at least one acoustic attenuation member 3a arranged on the lower wall 7 of the duct 2 and the neck 5b of the at least one acoustic attenuation member 3b arranged on the upper wall 6 of the duct 2 are arranged downstream of the section S formed by said acoustic attenuation members 3a, 3b in the direction of flow of the air flow. In other words, the necks 5a, 5b of the acoustic attenuation members 3a, 3b do not face the air flow F.

[0063] In this embodiment, all the acoustic attenuation members 3a, 3b (those arranged on the lower wall of the air flow duct, and those arranged on the upper wall of the air flow duct) comprise a cavity 4a, 4b and a neck 5a, 5b connecting said cavity 4a, 4b to said flow duct 2 of the air flow F, said neck 5a, 5b extending along a main extension axis Aa, Ab parallel to the direction of the air flow F in the flow duct 2 of the air flow F. The necks 5a, 5b of the acoustic attenuation members 3a, 3b open into the flow duct 2 of the air flow F by forming an opening 10a, 10b in said duct 2. Each of the necks 5a, 5b has an end section adjacent to the opening formed by the neck opening into the conduit, said section also being called downstream section 12a, 12b in this description.The neck 5a, 5b of each of the acoustic attenuation members 3a, 3b thus comprises an upstream section 11a, 11b adjacent to the cavity 4a, 4b of the acoustic attenuation member 3a, 3b and a downstream section 4a, 4b adjacent to the opening 1a, 10b formed by said neck 5a, 5b in the flow duct 2 of the air flow F. The acoustic attenuation device 1 is arranged so that the air flow F enters through the air inlet 14 of the flow duct 2 of the air flow F, circulates in the section S formed by the acoustic attenuation members 3a, 3b arranged on the upper 6 and lower 7 walls of the duct 2, emerging on the side of the downstream section 12a, 12b of said acoustic attenuation members 3a, 3b, then heads towards the air outlet 13 of the flow duct 2 of the air flow F. .

[0064] The neck 5a, 5b of the at least one acoustic attenuation member 3a, 3b faces the air outlet 13 of the air flow duct 2. Thus, the neck 5a, 5b of the at least one acoustic attenuation member 3a, 3b is oriented in a direction opposite to the air inlet 14. In other words, the neck 5a, 5b of the acoustic attenuation member 3a, 3b does not face the air flow F circulating in the air flow duct 2 of air flow F.

[0065] In this embodiment, the upstream section 11a of the neck 5a of the acoustic attenuation members 3a arranged on the lower wall 7 of the duct 2 is aligned with the upstream section 11b of the neck 5b of the acoustic attenuation members 3b arranged on the upper wall 6 of said air flow duct 2, along an axis substantially parallel to the direction of the air flow. In other words, there is no offset between the necks 5a, 5b along an axis substantially parallel to the direction of the air flow.

[0066] In the acoustic attenuation device shown in [Fig. 3], the upstream section 12a of the neck 5a of the at least one acoustic attenuation member 3a arranged on the lower wall 7 of the duct 2 is separated by a non-zero distance d from the upstream section 12b of the neck 5b of the at least one acoustic attenuation member 3b arranged on the upper wall 6 of said flow duct 2 of the air flow F, the distance d extending along an axis substantially parallel to the direction of the air flow F. In other words, there is an offset between the necks 5a, 5b, in particular between the upstream sections 12a, 12b of said necks. The other characteristics of the device are similar to the characteristics of the device of [Fig. 2].

[0067] In the embodiment of [Fig. 4], the flow duct 2 of the air flow F comprises at least two acoustic attenuation members 3a, 3c superimposed on one another and arranged on the same wall of the flow duct of the air flow, here the upper wall 6 of the flow duct 2 of the air flow. In this example, the other wall of the flow duct of the air flow, here the lower wall 7 of said duct, comprises at least one acoustic attenuation member 3b.

[0068] The cavities 4a, 4b, 4c of the acoustic attenuation members 3a, 3b, 3c are formed by four faces. At least one face delimiting the cavity 4b of an acoustic attenuation member 3b is adjacent to a face delimiting the cavity 4c of the other acoustic attenuation member 3c which is superimposed thereon. In this embodiment, at least two necks 5b, 5c of acoustic attenuation members 3b, 3c of the same wall (here upper wall 6) of the flow duct 2 of the air flow F are oriented in the same direction, namely a direction substantially parallel to the direction of the air flow F.In other words, the neck 4b of at least one acoustic attenuation member 3b, called first acoustic attenuation member 3b, arranged on a wall 6 extends along a main extension axis Ab substantially parallel to the direction of the air flow F, and the neck 4c of another acoustic attenuation member 3c superimposed on said first acoustic attenuation member 3b extends along an extension axis substantially parallel to the direction of the air flow F. The neck 4a of the at least one acoustic attenuation member 3a arranged on the other wall 7 of the flow duct 2 of the air flow F is also oriented in this direction. The necks 4a, 4b, 4c of the acoustic attenuation members 3a, 3b, 3c are all aligned with each other. The other characteristics of the acoustic attenuation device of this embodiment are similar to those described for the embodiment of [Fig.2]. .

[0069] In the embodiment of [Fig.5], at least two necks 5b, 5c of acoustic attenuation members 3b, 3c of the same wall (here the upper wall 6) of the flow duct 2 of the air flow F are oriented in different directions. Indeed, the neck 4b of one of the acoustic attenuation members 3b, also called first acoustic attenuation member 3b, opens onto the flow duct 2 of the air flow F by forming an opening 10b in said duct 2, this neck 4b extends along a main axis of extension of the neck Ab substantially parallel to the direction of the air flow F, and the other acoustic attenuation member 3c which is adjacent to said first acoustic attenuation member 3b, also called second acoustic attenuation member 3c, comprises a neck 4c' which extends along a main axis of extension of said neck substantially perpendicular Ac' to the air flow.More precisely, the second neck 4c' of this second acoustic attenuation member 3c opens into the cavity 5b of the first acoustic attenuation member 3b, and the neck 4b of the first acoustic attenuation member 3b opens into the flow duct 2 of the air flow F in a direction parallel to the direction of the air flow F, the two necks extending in different directions, more precisely substantially perpendicular directions. . .

[0070] The other characteristics of this embodiment are similar to those of [Fig.4],

Claims

Claims

1. Acoustic attenuation device (1) configured to be mounted on a motor vehicle air intake, said device comprising: - at least one flow duct (2) for an air flow F intended to channel said air flow F along a flow direction of said air flow in the duct (2), said duct (2) being delimited by at least one wall (6, 7), - at least one acoustic attenuation member (3a, 3b, 3c) arranged at least in part on said wall (6, 7) of the flow duct (2) for the air flow (F), said acoustic attenuation member (3a, 3b, 3c) comprising a cavity (5a, 5b, 5c) and a neck (4a, 4b, 4c) connecting said cavity (5a, 5b, 5c) to said flow duct (2) for the air flow (F), said neck (4a, 4b, 4c) extending along a main extension axis (Aa, Ab, Ac) parallel to the direction of the air flow (F) in the flow duct (2) of the air flow (F).

2. Acoustic attenuation device (1) according to the preceding claim, characterized in that the flow duct (2) of the air flow (F) comprises at least one lower wall (7) and at least one upper wall (6), the upper wall (6) being arranged above the lower wall (7) when the acoustic attenuation device (1) is mounted on the vehicle and the lower wall (7) corresponding to the lower wall (7) when the acoustic attenuation device (1) is mounted on the vehicle, at least one acoustic attenuation member (3a) being arranged on the lower wall (7) of the flow duct (2) of the air flow (F) and at least one acoustic attenuation member (3b) being arranged on the upper wall (6) of the flow duct (2) of the air flow (F),a section (s) for the air flow being formed between the neck (4b) of the at least one acoustic attenuation member (3b) arranged on the upper wall (6) of the flow duct (2) of the air flow (F) and the neck (4a) of the at least one acoustic attenuation member (3a) arranged on the lower wall (7) of the flow duct (2) of the air flow (F).,

3. Acoustic attenuation device (1) according to claim 2, characterized in that the neck (4a) of the at least one acoustic attenuation member (3a) arranged on the lower wall (7) of the flow duct (2) of the air flow (F) and the neck (4b) of the at least one acoustic attenuation member (3b) arranged on the upper wall (6) of the flow duct (2) of the air flow (F) are arranged downstream of the section (s) formed by said necks (3a, 3b) in the direction of flow of the air flow (F).

4. Acoustic attenuation device (1) according to one of the preceding claims, characterized in that the air flow duct (2) comprises an air inlet (14) through which the air flow (F) enters and an air outlet (13) through which the air flow (F) exits, the neck (4a, 4b, 4c) of the at least one acoustic attenuation member (3a, 3b, 3c) facing the air outlet (13) of the flow duct (2) of the air flow (F).

5. Acoustic attenuation device (1) according to the preceding claim, characterized in that the neck (4a, 4b, 4c) of at least one acoustic attenuation member (3a, 3b, 3c) comprises an upstream section (11a, 11b, 11c) adjacent to the cavity (5a, 5b, 5c) of the acoustic attenuation member (3a, 3b, 3c) and a downstream section (12a, 12b, 12c) adjacent to the opening (10a, 10, 10c) formed by said neck in the flow duct (2) of the air flow (F), the acoustic attenuation device (1) being arranged so that the air flow (F) entering through the air inlet (14) of the air flow duct (2), circulates in the section (s) formed by the acoustic attenuation members (3a, 3b) arranged on the upper (6) and lower (7) wall of the flow duct (2) of the air flow (F) opening out on the side of the downstream section (12a, 12b) of said acoustic attenuation members (3a, 3b), then heads towards the air outlet (13) of the flow duct (2) of the air flow (F).

6. Acoustic attenuation device (1) according to one of claims 3 to 5, characterized in that the upstream section (11a) of the neck of the at least one acoustic attenuation member (3a) arranged on the lower wall (7) of the duct is separated by a non-zero distance (d) from the upstream section (11b) of the neck of the at least one acoustic attenuation member (2b) arranged on the upper wall (6) of said flow duct (2) of the air flow (F), the distance (d) extending along an axis parallel to the direction of the air flow (F).

7. Acoustic attenuation device (1) according to one of the preceding claims, characterized in that the cavity of the acoustic attenuation members comprises four faces, the neck of said members acoustic attenuation being arranged on one of these faces, and in that the acoustic attenuation device (1) comprises at least two acoustic attenuation members (3b, 3c) on the same wall of the air flow duct (2), at least one face delimiting the cavity (5b, 5c) of one of said acoustic attenuation members being adjacent to a face delimiting the cavity (5b, 5c) of the other acoustic attenuation member (3b, 3c).

8. Acoustic attenuation device (1) according to one of the preceding claims, characterized in that the acoustic attenuation device comprises on the same wall (6) of the air flow duct (F) at least one first acoustic attenuation member (3b) comprising a neck (4b) and at least one second acoustic attenuation member (3c) comprising at least one neck (4c, 4c'), said second acoustic attenuation member (3c) being superimposed on said first acoustic attenuation member (3b), at least one neck (4b) of the first acoustic attenuation member (3b) and at least one neck (4c) of the second acoustic attenuation member (3c) of the same wall of the air flow duct are parallel to each other and extend in a direction substantially parallel to the direction of the air flow (F).

9. Acoustic attenuation device (1) according to the preceding claim, characterized in that at least one neck (4b) of the first acoustic attenuation member (3b) and at least one neck (4c') of the second acoustic attenuation member (3c) of the same wall (6) of the flow duct (2) of the air flow (F) extend in different directions.

10. Front panel module of a motor vehicle comprising an acoustic attenuation device (1) according to one of the preceding claims, the acoustic attenuation device (1) being installed at an air inlet (14) on the front panel of the motor vehicle.