DAMPER ARRANGEMENT AND FLUID DUCT WITH A DAMPER ARRANGEMENT

Abstract

 The invention relates to a damper arrangement (10) for a fluid duct (50) having at least one duct portion (52) with one or more channels (12) projecting through a wall (16) of the duct portion (52) from an interior surface (22) to an exterior surface (24) of the duct portion (52) in an exit region (18), wherein a flexible element (32) is arranged on the exterior surface (24) of the wall (16) to overlap the exit region (18) of the one or more channels (12).

Description

Technical Field

[0001] The invention relates to a damper arrangement and a fluid duct with a damper arrangement, in particular for an air duct for a combustion engine.

Prior Art

[0002] EP 1 378 656 B1 describes a damper arrangement on an air duct of an internal combustion engine, the duct having a porous wall portion. The porous wall is covered by a thin film at the interior side of the duct. Only a part of the film is attached to the wall.

Disclosure of the Invention

[0003] It is an object of the invention to provide a damper arrangement which is reliable and can be easily assembled.

[0004] Another object of the invention is to provide a fluid duct having such a damper arrangement.

[0005] The objects are achieved by a damper arrangement for a fluid duct and a fluid duct having such a damper arrangement wherein the damper arrangement has at least one duct portion with one or more channels projecting through a wall of the duct portion from an interior surface to an exterior surface of the duct portion in an exit region, wherein a flexible element is arranged on the exterior surface of the wall to overlap the exit region of the one or more channels.

[0006] The other claims, the description and the drawings describe advantageous embodiments of the invention.

[0007] According to a first aspect of the invention, a damper arrangement for a fluid duct is proposed, having at least one duct portion with one or more channels projecting through a wall of the duct portion from an interior surface to an exterior surface of the duct portion in an exit region, wherein a flexible element is arranged on the exterior surface of the wall to overlap the exit region of the one or more channels.

[0008] Advantageously, the damper arrangement is suitable for damping duct modes in the frequency range of close to 0 Hz up to 1000 Hz. The damper arrangement may be integrated directly in the duct. The fluid duct may conveniently be an air duct in a combustion engine. In a combustion engine environment, the damper arrangement may be provided at the dirty air side and/or at the clean air side. Conventional damper arrangements known in the art can be arranged at the dirty air side only.

[0009] Advantageously, the cross sections, the sizes, the arrangement as well as the number of the channels in the duct may be determined by conventional acoustic simulation calculations and/or by experimental tests and can be adapted to a desired frequency or frequency range of sound waves to be damped.

[0010] The flexible element may be a diaphragm, a layer, a thin film or the like. The duct may be a rigid duct. The flexible element may be welded, glued, pinched or clipped to the duct portion preferably along the flexible element's perimeter.

[0011] According to an advantageous embodiment, the flexible element may be arranged spaced apart from the exit region. Advantageously, when a fluid pressure in the duct is lower than a pressure outside the duct, the flexible element cannot close the channels which would be detrimental to the damper characteristics.

[0012] According to an advantageous embodiment, the flexible element may be part of a predominantly air-tight enclosure confining a volume having a fluidic connection to the one or more channels. By providing an air tight area above the channels it is possible to eliminate suction of unwanted fluid, e.g. hot air, dust, water and the like, into the fluid duct under respective pressure conditions. Thus, the damper arrangement is suitable for mounting in a clean air duct.

[0013] According to an advantageous embodiment, the flexible element may be configured to be air-tight at least under normal operation conditions. By providing an air tight flexible element above the channels it is possible to eliminate suction of unwanted fluid, e.g. hot air, dust, water and the like, into the fluid duct under respective pressure conditions. Thus, the damper arrangement may be installed in a clean air duct.

[0014] According to an advantageous embodiment, the flexible element may be configured to have an undulated surface. Advantageously, the damping characteristics of the damper arrangement are not declined by the flexible element.

[0015] According to an advantageous embodiment, the flexible element may be configured to be self-supporting. The flexible element is flexible enough to move in vertical direction but is stable enough not to sag and inadvertently block the exit portion of the channels which would deteriorate the acoustic effect of the channels. Stability may be generated by one or more of material, material thickness, stiffening corrugations and the like.

[0016] According to an advantageous embodiment, the flexible element may have a material thickness of not more than 100 µm, preferably not more than 90 µm, more preferably of not more than 80 µm, even more preferably not more than 50 µm. The thickness may be chosen depending on the material of the flexible element and/or on the size of the exit portion of the channels which has to be covered by the flexible element. Preferably, the thickness is chosen small enough in order not to deteriorate the acoustic effect of the flexible element.

[0017] According to an advantageous embodiment, the flexible element may be covered with a protective cover. Advantageously, the protective cover protects the flexible element from being damaged during usage of the duct. The protective cover may be an injection molded part. In particular, the protective cover may provide one or more openings. The openings may be arranged at the sides and/or the top of the protective cover. The shape of the openings may be circular, rectangular, square shaped, triangular or the like and may be selected to allow a suitable characteristic of the damper arrangement without allowing punching or tearing the flexible element. The protective cover may be clipped, welded or glued with the duct portion all over the protective cover's perimeter. Favorably, the flexible element and the protective cover may be attached to the duct portion together in one assemble step. Preferably, a distance between the flexible element and the protective cover is at least 1 mm in order to allow free movement of the flexible element during operation of the fluid duct and not to deteriorate the acoustical behavior of the damper arrangement.

[0018] According to an advantageous embodiment, the protective cover may comprise a weldable material. A suitable weldable material is polypropylene, for instance.

[0019] According to an advantageous embodiment, the duct may be a rigid element, preferably a duct manufactured by injection molding or blow molding.

[0020] According to another aspect of the invention a fluid duct is proposed comprising a damper arrangement according to the invention. The duct comprises at least one damper arrangement, having at least one duct portion with one or more channels projecting through a wall of the duct portion from an interior surface to an exterior surface of the duct portion in an exit region, wherein a flexible element is arranged on the exterior surface of the wall to overlap the exit region of the one or more channels. Favorably, acoustic duct modes can be damped between close to 0 Hz and up to 1000 Hz.

[0021] The fluid duct may be preferably provided as an air duct for a combustion engine. Favorably, the fluid duct may be mounted as an air duct on the dirty side and/or the clean side of a combustion engine. The duct provides at least one dedicated duct portion for assembly of the flexible element. The damper arrangement can be integrated directly into the duct. Optionally, a duct portion equipped with such a damper arrangement can be flanged or otherwise connected to the duct.

Brief Description of the Drawings

[0022] The present invention together with the above-mentioned and other objects and advantages may best be understood from the following detailed description of the embodiments, but not restricted to the embodiments, wherein is shown in:

Fig. 1

a top view of a duct comprising a damper arrangement according to an embodiment of the invention;

Fig. 2

a cross-cut view through a damper arrangement comprising a duct portion according to an embodiment of the invention;

Fig. 3

a longitudinal cut view through a damper arrangement comprising a duct portion according to an embodiment of the invention;

Fig. 4

a cross-cut view through a damper arrangement comprising a duct portion according to an embodiment of the invention;

Fig. 5

an isometric view of a damper arrangement comprising a duct portion depicted without flexible element and protective cover according to an embodiment of the invention;

Fig. 6

an isometric view of a damper arrangement comprising a duct portion according to an embodiment of the invention comprising a protective cover with slit-like openings on the top of the protective cover;

Fig. 7

an isometric view of a damper arrangement comprising a duct portion according to an embodiment of the invention comprising a protective cover with rectangular openings at the sides of the protective cover;

Fig. 8

an isometric view of a protective cover with various shapes of openings on the top of the protective cover according to an embodiment of the invention.

Detailed Description of the Drawings

[0023] ln the drawings, like elements are referred to with equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.

[0024] Figure 1 depicts a top view of a fluid duct 50, such as an air duct of a combustion engine, comprising a damper arrangement 10 arranged in a duct portion 52 according to an embodiment of the invention. The duct 50 may be provided with more than one such duct portions 52. The duct 50 has preferably a rigid body made by injection molding or blow molding, for instance. The damper arrangement 10 damps the duct modes in a desired frequency range, e.g. between 0 Hz and 1000 Hz, which can be selected by the properties of the damper arrangement 10.

[0025] Figure 2 shows a view of a cross cut through a damper arrangement 10 comprising a duct portion 52 for a fluid duct 50 (Figure 1) according to an embodiment of the invention, while Figure 3 shows a view of a longitudinal cut through the damper arrangement 10 of Figure 2. The damper arrangement 10 has at least one duct portion 52 comprising one or more channels 12 projecting through a wall 16 of the duct portion 52 from an interior surface 22 to an exterior surface 24 of the duct portion 52. The openings of the channels 12 in the exterior surface 24 define an exit region 18. The exit region 18 is overlapped by a flexible element 32 which is arranged on the exterior surface 24 of the wall 16.

[0026] The channels 12 may have any cross section appropriate for damping a desired frequency or frequency range, such as circular, longitudinal, elliptical, triangular or the like. Shape, number, cross section, size and position of the channels 12 can be generated by acoustic simulation or experimental tests, both known in the art.

[0027] The flexible element 32 may be a diaphragm or the like and is preferably made of a weldable material such as polypropylene. A preferred thickness of the flexible element 32 may be chosen to be not more than 100 µm, preferably not more than 80 µm. The flexible element 32 is arranged spaced apart from the exit region 18 in an appropriate distance in order to avoid blocking of the channels 12 in cases when the pressure in the duct portion 52 is lower than outside.

[0028] The flexible element 32 is configured to be air-tight at least under normal operation conditions. Preferably, the flexible element 32 is part of an air-tight enclosure of the exit region at the exterior surface 24 and confining a volume 36 having a fluidic connection to the channels 12. The exit region 18 in this embodiment is surrounded by a frame 30 onto which the flexible element 32 is mounted by welding, gluing, pinching or the like. Although the connection between the flexible element 32 and the frame 30 needs not necessarily to be air-tight, an air-tight connection is preferred. A preferred material for the flexible element 32 is polypropylene.

[0029] Preferably, the flexible element 32 has an undulated surface 34 which may be preformed before assembly or become undulated during assembly of the damper arrangement 10. Optionally, however, the flexible element 32 may be flat without undulations.

[0030] The frame 30 provides a plane surface for connecting the flexible element 32 which facilitates the assembly. It is to be understood, however, that the frame 30 may be curved following the curvature of the exterior surface 24 of the duct portion 52.

[0031] The flexible element 32 is covered by a protective cover 40 which, in this embodiment, comprises an opening 44 at each side wall of the protective cover 40. The openings 44 are selected to allow undisturbed operation of the flexible element 32. Additionally or altematively, openings 44 may be provided in other regions of the protective cover 40. The protective cover 40 is preferably an injection-molded part.

[0032] The flexible element 32 is arranged between the frame 30 of the duct portion 52 and the protective cover 40 and may be assembled together with the protective cover 40 instead of being preassembled prior to mounting of the protective cover 40.

[0033] Figure 4 shows a cross-cut view through a damper arrangement 10 comprising a duct portion 52 according to an embodiment of the invention.

[0034] The features of the damper arrangement 10 correspond to the features described in Figures 2 and 3, except that the protective cover 40 does not have openings 44 in the side walls 42 of the protective cover 40 but are arranged in the top surface of the protective cover 40. In order to avoid unnecessary repetitions, reference is made to the descriptions of Figures 2 and 3 for the other details of the damper arrangement 10. Preferably the openings 44 are large enough for providing undisturbed movement of the flexible element 32 during operation but small enough to protect the flexible element 32 against damage from outside.

[0035] Figure 5 shows an isometric view of a damper arrangement 10 comprising a duct portion 52 depicted without flexible element 32 and protective cover 40 according to an embodiment of the invention. The features of the damper arrangement 10 correspond to the features described in Figures 2 and 3. In order to avoid unnecessary repetitions, reference is made to the descriptions of Figures 2 and 3 for the other details of the damper arrangement 10. The exit region 18 of channels 12 at the exterior surface 24 of the wall 16 is surrounded by the frame 30 onto which the flexible element 32 is attached with its perimeter.

[0036] Figures 6 and 7 show isometric views of damper arrangements 10 comprising a duct portion 52 according to embodiments of the invention comprising a protective cover 40 with slit-like openings 44 on the top of the protective cover 40 (Figure 6) or openings 44 in the side walls 42 of the protective cover 40 (Figure 7). Again, the other details of the damper arrangement 10 correspond to the features in the aforementioned embodiments to which reference is made for more details.

[0037] Figure 8 depicts an isometric view of a protective cover 40 with various cross sections of openings 44 arranged on the top of the protective cover according to an embodiment of the invention, such as circular, triangular or longitudinal cross sections. The protective cover 40 is provided with a flange 46 at its perimeter thus facilitating a connection between the protective cover 40 and the frame of the duct portion 52.

[0038] The cross sections, the arrangement, the sizes and the number of the openings 44 may be selected in order to allow an undisturbed behavior of the flexible element 32 by protecting it from damage at the same time.

[0039] Referring to all embodiments described, by providing an air-tight flexible element 32 and an predominantly air-tight enclosure around the exit region 18 the duct 50 may be mounted in dirty as well as clean conditions as an exchange between fluids, in particular air inside the duct 50 and medium outside the duct 50, in particular air, can be avoided. Thus, hot air, dust as well as water can be prevented from entering the duct 50 in the exit regions 18 of the channels 12.

Claims

1. Damper arrangement (10) for a fluid duct (50) having at least one duct portion (52) with one or more channels (12) projecting through a wall (16) of the duct portion (52) from an interior surface (22) to an exterior surface (24) of the duct portion (52) in an exit region (18), wherein a flexible element (32) is arranged on the exterior surface (24) of the wall (16) to overlap the exit region (18) of the one or more channels (12).

2. Damper arrangement according to claim 1, wherein the flexible element (32) is arranged spaced apart from the exit region (18).

3. Damper arrangement according to claim 1 or 2, wherein the flexible element (32) is part of a predominantly air-tight enclosure confining a volume (36) having a fluidic connection to the one or more channels (12).

4. Damper arrangement according to any one of the preceding claims, wherein the flexible element (32) is configured to be air-tight at least under normal operation conditions.

5. Damper arrangement according to any one of the preceding claims, wherein the flexible element (32) is configured to have an undulated surface (34).

6. Damper arrangement according to any one of the preceding claims, wherein the flexible element (32) is configured to be self-supporting.

7. Damper arrangement according to any one of the preceding claims, wherein the flexible element (32) has a material thickness of not more than 100 µm, preferably not more than 90 µm, more preferably of not more than 80 µm.

8. Damper arrangement according to any one of the preceding claims, wherein the flexible element (32) is covered with a protective cover (40).

9. Damper arrangement according to claim 8, wherein the protective cover (40) provides one or more openings (44).

10. Damper arrangement according to any one of the preceding claims, wherein the protective cover (40) comprises a weldable material.

11. Damper arrangement according to any one of the preceding claims, wherein the duct (50) is a rigid element, preferably a duct manufactured by injection molding or blow molding.

12. Fluid duct comprising a damper arrangement (10) according to any one of the preceding claims, in particular for an air duct for a combustion engine.

Drawing