Arrangement with sound attenuation insert for an engine intake air circuit and method of assembly

Abstract

For noise attenuation in the engine intake air circuit, it is provided to combine: a rigid pipe (2) having an access opening (20) and an inner stop part provided at a distance from the end forming said opening; and an insert (5) having a perforated tubular framework, and also an acoustic absorption element carried and / or held by the framework, covering a section (3) of the pipe, on an inner circumference. The insert (5) is housed inside the pipe (2) until it bears axially against the stop part, delimiting at the access opening a passage cross section of the same geometric shape, for example non-circular, as said end forming the opening (20). The insert (5) can be mounted at a fluidic connection downstream of an air filter (8), without modifying the cross section of the pipe.

Description

ARRANGEMENT WITH SOUND REDUCING INSERT FOR ENGINE INTAKE AIR CIRCUIT AND METHOD OF ASSEMBLY Technical field

[0001] The invention relates to equipment for the air intake circuit for a thermal engine, in particular for a motor vehicle, in particular noise reduction systems, for example to limit the sound upstream of a turbo or similar area preceding the intake plenum. An arrangement with a sound reduction insert for an engine intake air circuit, an air suction device and a method of assembling the arrangement are proposed. Technological background

[0002] To enable attenuation of the sound produced in an engine intake air duct, it is known to use a porous duct wall having a heterogeneous structure in order to integrate a porous material. This type of configuration tends to weaken the duct and / or reduce its rigidity.

[0003] In the engine air intake circuit, it is thus known from document EP2754881 or document EP1 116875 to modify the structure of the pipes to allow a sound attenuation effect. Furthermore, there are pipe configurations with the addition of a sound absorption part outside the pipe and / or by the creation of an attenuation layer occupying a bulge or area with a significant increase in section. A solution by inserting a sound absorption element has been proposed in document DE 3531353. The construction of such an element requires gripping edges and the structure of the pipes must be adapted in a junction zone, with the use of flared parts (generating more space by a significant widening).

[0004] There is therefore a need for less restrictive systems for the design of pipes used to channel air intended for the intake of a thermal engine. Summary

[0005] In order to improve the situation, a noise attenuation arrangement for an engine intake air circuit is proposed, the arrangement comprising: - a rigid pipe having an annular end delimiting an access opening, the pipe further having a stop portion provided at a distance from the annular end, the pipe including a section extending annularly around a central axis between the stop portion and the annular end; - an insert, having an openwork tubular frame which extends between a first end and a second end, the insert including a porous foam or media which has a thickness determined by being carried and / or maintained by the framework by covering the section, on an internal circumference of this section; knowing that the insert is inserted inside the pipe, preferably fully inserted, until it axially bears against the stop part by the first end of the framework which locally reduces the passage section of the pipe, the insert delimiting in the inserted state, at the level of the access opening, a passage section of the same geometric shape, preferably non-circular, as said annular end of the pipe.

[0006] Thanks to these provisions, it is possible to obtain a high-performance and removable noise reduction system, without or with a minimum of pipe modification. The insert of the arrangement can be placed in the desired area: it can be easily installed and removed, being accessible via the access opening. Furthermore, the foam or porous media can be adapted or changed according to the acoustic performance needs. An elastically deformable sleeve shape can be preferred to form the foam. The insert allows a covering of the internal face of the section, which can be complete / carried out on the entire internal circumference of the section.

[0007] The assembly operation is simple, without the need for a specifically enlarged or specific fitting, the foam or porous media being previously secured to the frame, so that the insert corresponds to a pre-assembled removable unit. Typically, the insert is inserted removably (in one piece) into the pipe, being able to be removed from the section via the access opening through which it was inserted. This assembly can be carried out by sliding, without fitting with a clip.

[0008] In the implementation options, one or more of the following features can be provided: - the stop part is in the form of one or more internal stops and / or in the form of a variation in section. - the stop portion includes at least one internal protrusion. - the annular end of the pipe constitutes a male part of a fluid connection device. - the insert can be rotated in rotation, in the section. - the insert may have a non-circular perimeter coinciding with an internal circumference with a non-circular and continuously rounded section of the section (the installation of the attenuation layer may then be guided and indexed in rotation, with the possibility of orienting lateral openings of the frame according to predetermined angular sectors, which may typically make it possible to optimize the sound attenuation effect). - the insert has one or two planes of symmetry, along a longitudinal axis of the frame. - the frame is optionally made in one piece. - the frame is provided with a hinge, parallel to a longitudinal axis of the frame. - the foam or porous media is added around or directly overmolded onto a grid belonging to the frame. - the porous foam or media includes at least one of: a non-woven media, preferably based on synthetic fibers; and a reticulated foam based on a synthetic flexible plastic material, preferably polyethylene. - the porous or foamed media may consist of a non-woven layer, including or made of synthetic fibers. - the porous or foamed media may consist of a reticulated foam, preferably with the proviso that the fibers constituting it are held together, without the possibility of release.

[0009] Regardless of the intended attachment of the foam, the grid can be arranged either along an inner side face of the tubularly shaped foam, or along an outer face of this foam. When overmolding of the foam or porous attenuation means is planned, this can be done either on the inside or the outside of the frame.

[0010] The frame may have an opening conformation or configuration with two edges that are disjointed / spaced apart from each other. A hinge or equivalent connection is provided, for example, when the opening configuration results from a separation of the two edges, which may be complementary to each other, possibly parallel to each other in the opening configuration. According to a particular feature, the frame has a hinge connection made from the same material as the rest of the frame and is able to pass from one to the other between: - an open and deployed configuration, incompatible with insertion of the insert into the section via the access opening, - and a closed configuration, allowing the insert to be inserted into the section via the access opening.

[0011] The frame may include two parts, preferably forming two halves of the frame, designed separately and joined by a hinge connection which extends parallel to the central axis in the inserted state of the insert. Where a hinge is provided, the arrangement may have attachment means including at least one clip configured to allow the junction between two edges of the frame which may move apart in an opening configuration of the hinge belonging to the frame.

[0012] In embodiments of the frame, one or more of the following features may be provided: - the frame includes longitudinal stiffening ribs, for example protruding ones radially opposite an annular layer formed by the foam. - the longitudinal ribs protrude radially inwards. - the determined thickness is between 3 and 10 mm, preferably between 4 and 8 mm. - the frame has two radially outwardly projecting edges, between which the foam or porous media is held. - the ribs can extend from one to the other of the annular ends of the frame. - a rigid plastic frame can be used, with a relatively low thickness, for example less than 2 mm, with the exception of longitudinal ribs (which, unlike transverse ribs, do not disturb the flow).

[0013] According to a feature, the annular end of the pipe has an inner circumference making it possible to define a first passage section substantially equal to the passage section in the rest of the section. Optionally, the pipe is bent so as to define a bent zone with a second passage section which is located downstream of the first passage section and has a smaller characteristic dimension less than a characteristic diameter of the first passage section.

[0014] Optionally, the pipe forms a rigid, bent block that connects to an air filter outlet. The annular end of the pipe optionally forms a male part of a fluid connection device. The pipe defines a vacuum duct, preferably a duct upstream of a turbo.

[0015] According to another aspect, there is provided a suction device forming a duct in an air suction circuit, in particular for an internal combustion engine, the device comprising a first element and a second element connected in series one behind the other to form said duct, in which the first element is in fluid communication with an outlet of an air filter, through which a flow of purified air can circulate, with the particularity that the device includes the arrangement as defined above, so that the pipe constitutes all or part of the second element by making the connection with the first element, and in which the insert of the arrangement is adapted to be selectively inserted into the second element through the access opening, in order to cover an inner circumference of the second element, while the first element has an edge or an end adapted to abut against the insert,whereby the insert is held in a predetermined insertion position, in the inserted state in the second element, between the stop part belonging to the second element and the first element, without an intermediate piece.

[0016] Thanks to these provisions, a system for reducing engine emissivity noise is obtained that does not modify the connection structure between the components of the air circuit, without specific / additional connection and allowing the integration of a acoustic foam (e.g. about 4 mm thick) or thin porous media with a tubular structure, attached to / supported by the insert frame. Noise reduction can be made effective, for example, in any intermediate duct between the filter element (air filter) and the inlet of a turbo.

[0017] In embodiments, the device has one or more of the following features / arrangements: - the second end of the frame has an annular geometry, possibly without discontinuity (without slot or opening). - the second end includes an inner face or surface that can be flared away from the first end, which can optionally be enabled by progressively thinning this second end. - the adsorption layer (typically defined / consisting of foam or porous media) is elastically prestressed to press against the frame, for example due to a nominal diameter smaller than the external diameter of the frame in the covered area. - a sound absorption layer is formed which includes slightly extensible fibers, allowing expansion then retraction of its inner face which is opposite an external lateral face of the frame (the elasticity allows expansion for the installation of the sound absorption element, like an elastic sleeve or sock without a closed end).

[0018] According to another aspect, there is provided a method of assembling a noise attenuation arrangement for equipping an air intake line for an internal combustion engine, the method comprising the steps essentially of: - provide a hollow insert, having an openwork tubular frame which extends between a first end and a second end, with a porous foam or media, generally annular in shape, carried and / or held by the frame while having a determined thickness; - inserting the insert into a rigid pipe located downstream, in the direction of air flow in the intake line, of an outlet of an air filter, in which the pipe has an annular end delimiting an access opening through which the insert is inserted, the pipe further having a stop portion provided at a distance from the annular end so that the insert is inserted into the pipe until it abuts against the stop portion, and in which the insert is dimensioned so as, in the inserted state: to internally cover an annular section of the pipe with the first end which defines an annular circumference, for the passage of air leaving the hollow of the insert, which is locally reduced to define a passage section reduced compared to a zone air flow adjacent to the first end and delimited by the pipe, delimit, at the access opening, a passage section of the same geometric shape, preferably non-circular, as said annular end.

[0019] The insert, which may have a symmetry of revolution, is inserted into the pipe following the direction of air circulation, in order to extend around a central axis of the section which coincides with the axis of symmetry A of the insert. Where appropriate, the frame has an annular conformation obtained by connecting two parts by a hinge connection (these two parts being arranged in a closed configuration corresponding to the annular conformation, allowing insertion into the pipe), the openwork tubular frame being constituted / obtained in such an annular conformation.

[0020] Assembly is simple, using a pre-assembled insert with a robust design enabled by a rigid plastic frame. The sound-absorbing material, for example PET or foam-based material, can be fitted to the outside or inside of the frame, with a clamping effect. The foam or sound-absorbing media can be held in place by clamping. When the sleeve surrounds the frame, the inner diameter of the foam or similar material can be smaller than the outer diameter of the frame. Brief description of the drawings

[0021] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Figure 1 is a perspective view of an arrangement with an insert including a sound absorption element, for attenuating noise during the passage of air flowing in a pipe of the air intake line, according to an embodiment in accordance with the invention. Figure 2A illustrates in perspective a frame forming part of an insert such as that shown in Figure 1, in a first exemplary embodiment. Figure 2B illustrates in perspective another frame design, in a second exemplary embodiment. Figure 3A shows a side view of a noise attenuation insert, in an option with an outer absorption layer. Figure 3B shows a longitudinal section of the insert of Figure 3A. Figure 4 is a schematic view of an example assembly with the noise attenuation insert ready to be housed in a purified intake air circulation pipe. Description of embodiments

[0022] Referring to Figures 1 and 4, there is shown a noise attenuation arrangement 1 for an engine intake air circuit. Such an arrangement 1 may have a pipe 2 having an access opening 20, forming for example an inlet for an air flow F which circulates in an area downstream of a filtration stage. Figure 4 thus shows an air filter 8 provided with an outlet 8b and capable of being connected, directly or indirectly, to the pipe 2. More broadly, it is planned to introduce an insert 5 which has an acoustic absorption element 6, for example in the form of a sleeve carried by a frame 5c, into a pipe 2 forming part of the air intake line for an internal combustion engine, in particular for a vehicle. The pipe 2 can typically be provided upstream of a turbocharger.

[0023] The pipe 2 is rigid and has an annular end 2b delimiting an access opening 20 which may optionally be of non-circular shape. The insert 5 is hollow and provided with a rigid frame 5c, which has a section substantially of the same geometric shape as the section of the internal face of a section 3 of the pipe 2 in which the insert 5 is housed, for example by being entirely inserted into the section 3.

[0024] The insert 5 has a tubular frame 5c perforated so as to form large openings O. The insert 5 may have a longitudinal axis, which may optionally be an axis of symmetry. A grid structure may constitute said frame 5c, with two end pieces which each have a solid shape to define a termination ring. These rings may correspond respectively to the ends 5a and 5b of the insert 5. It may be provided that the sound absorption element 6 is shorter than the frame 5c, so as not to cover either the end 5a or the end 5b.

[0025] With reference to Figure 2A, and 2B, the insert 5 may have a symmetry of revolution around the axis A, which is typically a central / symmetry axis of the frame 5c. The frame 5c is for example made in a single piece by forming both the first end 5a or front end (“front” depending on the direction of insertion into the pipe 2) and the second end / rear end 5b. Alternatively, the frame 5c includes two complementary pieces. Optionally, the end 5b has a seamless annular geometry (without a slot or opening) and includes an inner surface S2 which may be flared away from the first end 5a, which may optionally be enabled by a progressive thinning of the end 5b.

[0026] In preferred options, the insert 5 carries / integrates a sound absorption part which is porous and typically flexible. A single-block design of this absorption part is preferred to simplify the assembly of the insert 5: a sound absorption element 6 of annular shape can thus be designed separately from the frame 5c before being fixed, overmolded or secured in any suitable manner on an openwork lateral face of this frame 5c. As clearly visible in FIGS. 2A to 3B, the frame 5c can be made up of a tubular structure, optionally non-cylindrical (to avoid any internal rotation in the receiving section 3), which covers the absorption element 6 from the inside. The frame 5c is provided with large openings O, for example each occupying more than a quarter of the total length of the insert 5 along the axis A.

[0027] The insert 5 may be devoid of a spacer or other transverse element occupying the hollow, so as to delimit a wide central passage. For example, the insert 5 has an internal face delimiting the central passage whose characteristic diameter is greater than 75% of the corresponding characteristic diameter (measured in the same direction transverse to the axis A) of the external lateral face F6 of the insert 5. In the case of Figure 3A, the external lateral face F6 is mainly defined / formed by an annular sound-absorbing portion, preferably in the form of a single piece constituting the element 6, with the central passage which is thus delimited by an inner face of the frame 5c which is configured with inner ribs 5d projecting (radially projecting inwards / towards the axis A) from an inner face of the frame 5c delimited by rings distributed / spaced along the length of the frame 5c, possibly at regular intervals to define openings O of the same dimension along this direction of the axis A. The different rings cross / connect to elongated members or rods T which can carry / internally the inner ribs 5d, longitudinal and parallel to the direction of the axis A.

[0028] The insert 5 and the pipe 2 are overlapped in the area of ​​the section 3. As illustrated in FIG. 1, the absorption part can then form an element 6 which covers from the inside a continuous area of ​​the section 3, over the entire inner circumference, without requiring to widen / increase the passage section of the pipe 2 near the opening 20, relative to the rest of the pipe. A stop part 4 can be provided inside the pipe 2 to allow a predetermined inserted state of the insert 5 to be obtained, which can for example be housed in the section 3 when the axis A is an axis of symmetry. When the section of the opening 20 is elliptical, two symmetrical insertion positions can be used indifferently.

[0029] In embodiments, the sound absorption element 6 is in the form of a foam or a porous, tubular media, which has a determined thickness e, for example less than or equal to 9 or 10 mm, and for example greater than a thickness of the members separating adjacent openings O. The thickness e can be between 3 or 4 mm and 8 mm, in a non-limiting manner.

[0030] As clearly visible in Figure 1, the section 3 has for example a tubular wall extending around a central axis X, ending with the annular end 2b, so that the central axis X can be a central axis or an axis of symmetry for the opening 20. The pipe 2 may have at least one stop portion 4 provided at a distance from the annular end 2b, in order to form one or more stop / abutment edges against which the insert 5 bears. In practice, the section 3 where the insert 3 is housed may extend in an annular manner (around the central axis X) between the stop portion 4 and the annular end 2b.

[0031] In the inserted state, the first end 5a of the insert 5, formed by the frame 5c, locally reduces the passage section SP1 of the pipe 2. Since the pipe 20 can have a substantially constant passage section at the section 3 and beyond, it is possible to obtain versatility in the choice of the insert 5. For example, if the insert 5 is relatively thin due to a noise reduction need satisfied with a small thickness e for the sound absorption element 6, then the variation in passage section at the insert 5 is small, with little pressure loss. The purified air flow F, leaving the hollow of the insert 5 via the passage section SP5 (and leaving the pipe opposite the end 2b) can flow into a pipe 2 which does not require a modification of its external geometry to accommodate the insert. The passage section SP5 can be defined by the end 5a which is optionally thinned on the side / in the direction of its axial free edge.

[0032] Conversely, if the corresponding noise attenuation requirement is very high, then it remains permissible to place a longer and / or thicker insert at the level of the sound absorption element 6, or even using a more efficient material (at equal thickness) than for the aforementioned requirement. Due to the substantially constant nature of the section of the pipe 2 at the level of the section 3 and beyond, the insert 5 can evolve to be longer and / or thicker, possibly emerging through the opening 20 with a thinned and / or extended projecting end (according to a modular design where appropriate, with end-to-end placement of the sound absorption modules) to be partially housed in another pipe or element E1 complementary to the pipe 2 or element E2 integrating the section 3.

[0033] Optionally, the frame 5c may form, at the end 5b, a groove G into which a relief, for example rounded to facilitate disengagement, for holding in position, provided on the pipe 20, on an auxiliary fixing component or on the complementary piping element or connection E1 (which may be a connection through which the air can be conveyed to the pipe 20, when the direction of circulation is of the type as provided in figure 4) may penetrate.

[0034] Despite the internal covering by the insert 5, the flow of the stream F is permitted adequately and without requiring adaptations of the pipe section. Furthermore, the insert 5 can be inserted and held in the section 3 in a removable manner, being capable to be removed from section 3 via the access opening 20. Indeed, the end 5b can form an accessible gripping zone for removing the insert 5 by simple traction.

[0035] In order to allow the air flow from the element E1 to pass entirely into the hollow of the insert 5, along the media or foam making up the sound absorption element 6, the frame 5c of the insert 5 may delimit, in the inserted state, a passage section at the access opening 20 which is of the same geometric shape, preferably non-circular, as the section defined at the annular end 2b. Optionally, a funnel shape may be defined by the surface S2, to ensure that the entire flow is collected in the hollow of the insert 5. The surface S2 is here located on the inlet side of the hollow, while the open end S1 allows the flow to leave the hollow of the insert 5. More broadly, the insert 5 may have an external circumference and a perimeter adapted to facilitate insertion into the section 3, preferably by having a non-circular perimeter coinciding with an internal circumference with a non-circular and continuously rounded section of the section 3. First option(s) for creating the insert frame

[0036] The framework 5c may be in the form of a rigid piece of plastic material, for example from a molding, as visible for example in Figure 2A. The ends 5a, 5b may be a pair of rings that are wider and / or more extended in the longitudinal direction than the intermediate rings that separate the openings O from each other. The reinforcement piece that constitutes the framework 5c is typically incompressible (non-deformable under the conditions of use), only the sound absorption element 6 being able to be compressed and / or deformed, in particular in the radial direction. The framework 5c allows the element 6 to be held, pressed against or shaped parallel to the inner face of the pipe 2 in the section 3.

[0037] A silent, heterogeneous sound attenuation insert 5 is thus formed, consisting of only two parts, namely an annular sound absorption element 6 made of flexible porous material (forming a foam) and the typically rigid tubular frame 5, here in the form of an openwork tube, optionally non-circular. The tubular frame 5c may for example form an inner part of the insert 5, while the annular absorption element 6 may be of the type retractable onto the frame 5c. In options and as visible in particular in FIG. 2A, the frame 5c may have one or two planes of symmetry, with a longitudinal axis A passing through the two open ends 21, 22 of the insert 5.

[0038] With this design, insert 5 can be quickly pre-assembled and then fitted into section 3 without risk of error. Especially when the frame section 5c is elliptical or has another non-circular and continuously rounded shape - in correspondence with the receiving section in section 3, the non-deformable 5c frame can allow efficient installation, without the use of tools or tedious rotational indexing. Second option(s) for creating the insert frame

[0039] With reference to the non-limiting case illustrated in Figure 2B, the insert 5 may have a plastic frame or framework made of two complementary parts 15, 16, forming for example two halves connected by a hinge h1, h2. These parts 15 and 16 may each be delimited by longitudinal edges 7, 8, extending between two axial end arcs. The ends 5a, 5b are thus each distributed in two parts. The two parts 15, 16 are capable of being assembled to obtain an annular frame conformation 5c, being joined by the respective longitudinal edges 7, 8 (joined two by two). In the assembled conformation, the two parts or parts 15, 16 may be kept connected using clips forming all or part of the fixing means MF.

[0040] For example, clipping tabs, elastically deformable clips or similar members included in one and / or the other part constituting the parts 15, 16, may be provided on the side of the longitudinal edges which are opposite the longitudinal edges connected by the hinge connection h1, h2. The clips may optionally be added after a molding step to obtain the similar complementary shells or parts 15, 16, if necessary after overmolding to secure the element 6 to the frame 5c.

[0041] In some embodiments the structure in two halves, connected by an elastic hinge, can be designed in one piece by molding. The hinge h1, h2 is in this case a plastic hinge made in one piece with the rest of the frame 5c. Two hinge parts h1, h2 spaced apart (axially separated) from each other can be formed, both in this one-piece variant and in other designs with joining of two separately designed parts. Example(s) of porous structure

[0042] The sound-absorbing element 6 supported / integrated by the frame may be made in a single piece of a porous or cellular plastic material. The material chosen may be PET or may include PET. Alternatively, an acoustic foam (with open porosity) may be produced, possibly based on polyethylene, optionally protected by at least one coating to prevent any risk of release.

[0043] The insert 5 may result from a step of fixing the sound absorption element 6 on an external periphery of the frame 5c, for example between two projecting edges radially outwards. This fixing step can be carried out by inserting the frame 5c into the hollow of the sound absorption element 6, which possibly has a wider axial opening on one side to facilitate this insertion by overlapping on one of the two edges which is optionally a beveled edge, with a sloping surface S1 which facilitates the insertion and axial progression of the end, here the end 5a, into the hollow of the element 6.

[0044] Generally speaking, when the frame 5c is surrounded by such a sound absorption layer, it is understood that the element 6 made of foam or based on an equivalent porous material can be held / held by clamping. In examples, the inner diameter of the element 6, before its installation, is less than an outer diameter D50 of the frame 5c. This diameter D50 can be substantially constant and provided in the middle of the frame 5c, with the possible exception that the frame 5c has one or two areas with a protruding edge or lug / relief, on the side of the end 5a and / or at the end 5b. With two opposite edges or any suitable relief, it is also possible to obtain: - axial support of the sound absorption layer; - a protective effect by guiding against the inside of section 3 (here on the side of end 5a) when the insert is put in place.

[0045] In some variants, an additional sound-absorbing layer is provided, possibly on the opposite side to the other layer with respect to the reinforcement / framework 5c, so that this frame 5c can be sandwiched between two means / layers with a sound-absorbing effect.

[0046] More generally, the insert 5 may have one end, with a retaining rim for the absorption element, which forms a tapered or sloping surface due to a thinning, for example progressive, in the direction of the free edge of the insert 5 at this end. The first end 5a by which the insert 5 is brought into the pipe 2 may have this type of surface S1 (surface S1 overlapped from the outside during the installation of the absorption element 6 and also capable of allowing guidance in the section 3 of the pipe 2, during insertion).

[0047] A reduction of several decibels can be achieved with a compact 5 insert, whose ratio between the length and a characteristic external diameter (larger diameter for example) remains for example between 1:2 and 2:1. Assembly example

[0048] The insert 5 can be pre-assembled in a simple manner, for example by ensuring that the sound absorption element 6 can be integrated into the thickness of the insert 5, without relative axial displacement with respect to the frame 5c (fixed mounting) even if this element 6 is subjected to friction against the interior of the pipe 2 during insertion.

[0049] The insertion can be done with a guiding effect enabled by the end 5a, an example of which is illustrated in Figure 3A for obtaining a sloping surface S1 which promotes centering at the start of insertion. For example, there can be a radial compression of the element 6 whose initial thickness is slightly reduced by contact against the internal face of the pipe 2. For this, the element 6 here defines an external lateral face F6 of the insert 5, with a radial projection outwards relative to the end 5a of the rigid frame 5c. In variants, the foam or porous media may be provided from the inside of the frame 5c and optionally may protrude radially outwardly (via the large openings O) in a similar manner relative to the frame 5c.

[0050] At the end of insertion, the insert 5 can be entirely housed in the section 3 axially, bearing against the stop part 4. With reference to Figure 4, this can be achieved in a pipe 2 constituting the second element E2 of a two-part conduit 10 with a connection which can correspond to the fluid connection provided at the outlet 8b of the air filter 8. More generally, on the upstream side through which purified air arrives (after purification in an air filter), a first element E1 can be used which can both: - connect to the first element E2 allowing the acoustic absorption element 6 carried by the insert 5 to be housed; - and block / maintain the position of insert 5, by opposing any movement of withdrawal of insert 5 from section 3.

[0051] The first element E1 may have an edge B or an end adapted to abut against the insert 5, with for example a predefined dimensioning for the distance between the stop part 4 and this edge B, which corresponds for example to the length of the insert 5, so that the latter is wedged / blocked in the axial position: a predetermined insertion position is thus obtained and maintained, typically without an intermediate piece. Optionally, the annular end 2b of the pipe 2 constitutes a male part of a fluid connection device.

[0052] It may be permissible to block the insert 5 without specific relief of the pipe 2 in the area of ​​the opening 20, therefore without particular adaptation in the section 3 near the end 2b. With reference to figures 3A and 3B, the groove G may not be associated with a relief of the pipe 2 and simply provide flexibility to optimize a radial compression effect of the annular zone 22 against the inside of the pipe, with an effect against accidental withdrawal of the insert 5, at least when the latter is in abutment against the stop part 4 by its end 5a. While the front open end 21 may for example abut axially against the stop part 4, without radial friction against the inside of the pipe so as not to hinder the insertion movement, the other open / rear end forming the flared annular zone 22 can rub (radially) against the internal face of the pipe 2 and / or of the element E1 by having an external diameter greater than that of the open end 21.

[0053] In the non-limiting example of Figure 4, the direction of insertion corresponds to the direction of circulation of the flow F of purified air (direction of circulation of air in the intake line). In variants, the insert 5 can be placed in a housing defined by a pipe located further upstream than the complementary pipe element, for example with an insertion opposite the direction of circulation of purified air. In all cases, the rear part following the direction of insertion can have a geometry and a section size which are adjusted to the geometry and the size of the access opening 20 through which the insertion is made, possibly so as not to protrude radially relative to the internal face of the pipe 2 and / or so as not to interfere with an end-to-end connection between the pipes / elements E1, E2 participating in the connection to make the pipe 10.

[0054] In the inserted state, the insert 5 has an absorption layer defined by the element 6, with a determined thickness e which is a function of the requirements. Thanks to the framework 5 which extends beyond the annular axial ends of the element 6, optionally with a non-circular geometry, it is possible to obtain a reliable hold of the insert with a suitable centering at both the end 5a and the end 5b.

[0055] In Figure 4, a non-limiting case is illustrated with the presence of a bent zone ZC in the pipe 2, for example downstream of the section 3 where the insert 3 can be housed. More generally, the pipe 2 can be bent, possibly with modifications in the geometry of the section. The annular end 2b has for example an inner circumference making it possible to define a first passage section substantially equal to the passage section SP1 in the rest of the section 3, which facilitates the integration of the insert5, while a second passage section SP2, different at least in its geometric shape, is present in the bent zone ZC. The second passage section SP2, located downstream of the first passage section SP1, can have a smaller characteristic dimension d2 which is less than a characteristic diameter of the first passage section SP1 (which can correspond to the diameter of the access opening 20).

[0056] It should be obvious to those skilled in the art that the present invention allows embodiments in many other specific forms without departing from the scope of the invention as claimed. For example, although the stop portion 4 has been illustrated in the form of a relief R projecting radially inwards relative to the axis X as shown in FIG. 1, it is permissible to obtain such a stop portion in a different way, for example without an internal relief with a section transition or a bent area having the same blocking effect.

Claims

CLAIMS 1. Noise attenuation arrangement (1) for an engine intake air circuit, the arrangement (1) comprising: - a rigid pipe (2) having an annular end (2b) delimiting an access opening (20), the pipe (2) further having a stop portion (4) provided at a distance from the annular end (2b), the pipe (2) including a section (3) extending annularly around a central axis (X) between the stop portion (4) and the annular end (2b); - an insert (5) having an openwork tubular frame (5c) which extends between a first end (5a) and a second end (5b), a porous foam or media (6) which has a determined thickness (e) being carried and / or held by the frame (5c) by covering the section (3), on an inner circumference of this section; in which the insert (5) is inserted inside the pipe (2), preferably fully inserted, until it axially bears against the stop part (4) by said first end (5a) which locally reduces the passage section (SP1) of the pipe (2), the insert (5) delimiting in the inserted state, at the access opening (20), a passage section of the same geometric shape, preferably non-circular, as said annular end (2b).

2. Arrangement according to claim 1, wherein the insert (5) is removably inserted into the pipe (2), being able to be removed from the section (3) via the access opening (20).

3. Arrangement according to claim 1 or 2, in which the foam or porous media (6) is added around or directly overmolded onto a grid belonging to the frame (5c), the frame being made in a single piece.

4. Arrangement according to claim 3, in which the frame (5c) has a hinge connection made in one piece with the rest of the frame and is capable of passing from one to the other between: - an open and deployed configuration, incompatible with insertion of the insert (5) into the section (3) via the access opening (20), - and a closed configuration, allowing the insertion of the insert (5) into the section (3) via the access opening (20).

5. Arrangement according to any one of claims 1 to 3, in which the foam or porous media (6) is added around or directly overmolded onto a grid belonging to the frame (5c), the frame (5c) including two parts forming preferably two halves of the frame, designed separately and joined by a hinge connection (h1, h2) which extends parallel to the central axis (X) in the inserted state of the insert (5).

6. Arrangement according to any one of the preceding claims, comprising fixing means (MF) including at least one clip configured to allow the junction between two edges (7, 8) of the frame (5c) capable of moving apart in an opening configuration of a hinge belonging to the frame (5c).

7. An arrangement according to any preceding claim, wherein the porous foam or media (6) includes at least one of: - a non-woven media, preferably based on synthetic fibers, and - a cross-linked foam based on a synthetic flexible plastic material, preferably polyethylene.

8. Arrangement according to any one of the preceding claims, in which the frame (5c) includes longitudinal stiffening ribs (5d) projecting radially opposite an annular layer formed by the foam, and in which the determined thickness (e) is between 3 and 10 mm, preferably between 4 and 8 mm.

9. Arrangement according to any one of the preceding claims, wherein said annular end (2b) has an inner circumference making it possible to define a first passage section substantially equal to the passage section (SP1) in the remainder of the section (3), and wherein the pipe (2) is bent so as to define a bent zone (ZC) with a second passage section (SP2) which is located downstream of the first passage section (SP1) and has a smaller characteristic dimension (d2) less than a characteristic diameter of the first passage section (SP1).

10. Suction device (10) forming a conduit in an air suction circuit, in particular for an internal combustion engine, the device (10) comprising a first element (E1) and a second element (E2) connected in series one behind the other to form said conduit, in which the first element (E1) is in fluid communication with an outlet (18) of an air filter (8), through which a purified air flow can circulate, characterized in that the device (10) includes the arrangement (1) according to any one of the preceding claims, so that the pipe (2) constitutes all or part of the second element (E2) by making the connection with the first element (E1), and in which the insert (5) of said arrangement (1) is adapted to be selectively inserted into the second element (E2) through the access opening (20), in order to cover an inner circumference of the second element (E2), while the first element (E1) has an edge (B) or an end adapted to abut against the insert (5), whereby the insert (5) is held in a predetermined insertion position, in the state inserted into the second element (E2), between said stop portion (4) belonging to the second element (E2) and the first element (E1), without an intermediate piece.

11. Method of assembling a noise attenuation arrangement (1) intended to equip an air intake line for an internal combustion engine, the method comprising the steps essentially consisting of: - providing a hollow insert (5), having an openwork tubular frame (5c) which extends between a first end (5a) and a second end (5b), with a porous foam or media (6), of generally annular shape, carried and / or maintained by the frame (5c) while having a determined thickness (e); - inserting the insert (5) into a rigid pipe (2) located downstream, in the direction of air circulation in the intake line, of an outlet (8b) of an air filter (8), in which the pipe (2) has an annular end (2b) delimiting an access opening (20) through which the insert (5) is inserted, the pipe (2) further having a stop portion (4) provided at a distance from the annular end (2b) so that the insert is inserted into the pipe (2) until it abuts against the stop portion (4), and in which the insert (5) is dimensioned so as, in the inserted state: to internally cover an annular section (3) of the pipe (2) with said first end (5a) which defines an annular circumference, for the passage of air leaving the hollow of the insert, which is locally reduced to define a passage section (SP1) reduced compared to a flow zone air adjacent to the first end (5) and delimited by the pipe (2), delimit,at the access opening (20), a passage section of the same geometric shape, preferably non-circular, as said annular end (2b)., 12. Assembly method according to claim 11, in which the insert (5) which has a symmetry of revolution is inserted into the pipe (2) in the direction of air circulation, in order to extend around a central axis (X) of the section (3) coinciding with the axis of symmetry (A) of the insert.

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