Conduit with integrated acoustic attenuators and method for the production thereof

Abstract

 The present invention relates to a gaseous fluid circulation conduit or pipe, provided with an arrangement of acoustic attenuators, extending laterally in the region of an intermediate segment of said conduit or pipe and opening into the interior volume of said segment; the arrangement comprises a multi-hole silencer (2) and two quarter-wave attenuators (3 and 3') disposed so as to be acoustically coupled to said silencer (2); the intermediate segment (4) has a structure substantially rectilinear with a central circulation axis or median axis. The multi-hole silencer (2), on the one hand, and the two quarter-wave attenuators (3 and 3'), on the other hand, are located either side of the median axis of the segment (4) so as to form, together with this silencer (2) and these two attenuators (3 and 3'), a single-piece structure (5) with a substantially flat configuration or constitution.

Description

[0001] The present invention relates to the field of gaseous fluid circulation conduits and pipes, in particular those forming part of the equipment and parts of vehicles with an internal combustion engine and has for its object a conduit or pipe of the aforementioned type comprising integrated acoustic attenuators, and a method for the production thereof.

[0002] Numerous constructions of fluid circulation conduits or pipes comprising acoustic attenuators, designed to reduce the noises and sounds conveyed by said fluids, or resulting from the flow thereof, are already known. French patent application No. 01 00191, dated 8 January 2001, and No. 02 07303, dated 13 June 2002, in the name of the Applicant, show examples of conduit/attenuator assemblies of this type.

[0003] There is, however, a constant demand for assemblies of the aforementioned type having higher attenuation performance levels and a smaller size, in particular when they are designed to be fitted in the space under the bonnet of a motor vehicle.

[0004] Moreover, a conduit/attenuator assembly of this type should be easy and inexpensive to produce, and have high vibration and impact resistance.

[0005] The object of the present invention is, in particular, to respond to the aforementioned demand.

[0006] For this purpose, the invention relates to a gaseous fluid circulation conduit or pipe, provided with an arrangement of acoustic attenuators, extending laterally in the region of an intermediate segment of said conduit or pipe and opening into the interior volume of said segment, characterised in that said arrangement comprises a multi-hole silencer and two quarter-wave attenuators, said quarter-wave attenuators being disposed so as to be acoustically coupled to said silencer, in that said intermediate segment has a substantially rectilinear structure with a central circulation axis or median axis, and in that the multi-hole silencer, on the one hand, and the two quarter-wave attenuators, on the other hand, are located either side of said median axis of said segment, so as to form, together with this silencer and these two attenuators, a single-piece structure with a substantially flat configuration or constitution.

[0007] A better understanding of the invention will be facilitated by the following description, which relates to a preferred embodiment, given by way of a non-limiting example, and explained with reference to the accompanying schematic drawings, in which:

Figures 1 and 2 are perspective views, from two different angles, of a conduit or pipe with integrated acoustic or vibration attenuators according to the invention;

Figures 3 and 4 are a lateral elevation and a rear view, respectively, of the conduit or pipe shown in Figures 1 and 2;

Figures 5 and 6 are exploded perspective views showing the two constituent parts of the structure with a substantially flat constitution, formed by the multi-hole silencer/intermediate segment/quarter-wave attenuators assembly forming part of the conduit or pipe shown in Figures 1 to 4, and

Figure 7 is an exploded perspective view showing the two constituent parts forming, by joining, the conduit or pipe shown in Figures 1 to 4.

[0008] Figures 1 to 4 and 7 of the accompanying drawings show a conduit or pipe 1 for the circulation of gaseous fluid, in particular a gaseous mixture of various gaseous fluids, provided with an arrangement of acoustic attenuators 2, 3, 3' extending laterally in the region of an intermediate segment 4 of said conduit or pipe 1 and opening into the interior volume of said segment 4.

[0009] According to the invention, said arrangement of attenuators comprises a multi-hole silencer 2 and two quarter-wave attenuators 3 and 3', said quarter-wave attenuators 3 and 3' being disposed so as to be acoustically coupled to said silencer 2. Said intermediate segment 4 has a structure that is substantially rectilinear with a central circulation axis or median axis X, and the multi-hole silencer 2, on the one hand, and the two quarter-wave attenuators 3 and 3', on the other hand, are located either side of said median axis X of said segment 4, so as to form, together with this silencer 2 and these two attenuators 3 and 3', a single-piece structure 5 with a substantially flat configuration or constitution.

[0010] Preferably, as emerges, in particular, from Figures 3, 4 and 5 of the accompanying drawings, the multi-hole silencer 2 and the two quarter-wave attenuators 3 and 3' have, viewed in lateral elevation in the median plane PM of the structure 5 with a flat configuration, formed by the multi-hole silencer 2/intermediate segment 4/quarter-wave attenuators 3 and 3' assembly, or in a plane parallel to this median plane, a thickness or an exterior height at most substantially equal to the thickness or the exterior height of the intermediate segment 4, in the direction perpendicular to said median plane PM, said median plane PM containing the central circulation or median axis X of said intermediate segment 4.

[0011] According to an advantageous practical construction variant of the invention, the multi-hole silencer 2 consists of a caisson or similar closed hollow body, formed on the wall of the intermediate segment 4 and communicating with the interior volume thereof through a plurality of openings 2', and each of the two quarter-wave attenuators 3 and 3' consists of a hollow body in the form of a deformation towards the exterior, forming a cavity in the wall of the intermediate segment 4, the two attenuators 3 and 3' having different dimensions, in particular different depths.

[0012] These openings 2' may, for example, be in the form of through-perforations provided in the wall portion, common with the silencer 2, of the intermediate segment 4, and forming a wall portion contributing to the delimitation of the interior volume of said silencer.

[0013] As an alternative, not shown in the accompanying drawings, the openings 2' may also be in the form of through-perforations provided in a plate or the like, made of a metallic or rigid synthetic material, mounted in a cut-out of the wall portion, common with the silencer 2, of the intermediate segment 4, the edges of said plate defining baffle structures with the edges of said cut-out.

[0014] The multi-hole silencer 2 may, for example, have a parallelepiped, preferably rectangular, shape, and each of the quarter-wave attenuators 3 and 3' consist of a cylindrical cavity, with a circular or non-circular section.

[0015] The large opposite walls delimiting the sound-proofing caisson of the multi-hole silencer, in the form of a flattened parallelepiped, may advantageously be connected to the wall of the intermediate segment 4 by reinforcing ribs 4', rigidifying their mutual connection.

[0016] The respective relative dispositions of the quarter-wave attenuators 3 and 3' in relation to the multi-hole silencer 2, in the direction of fluid flow in the segment 4, may be varied, as a function, in particular, of the desired attenuation profile.

[0017] The two attenuators 3 and 3' may thus both be located upstream or downstream of said silencer 2, or alternatively, as shown in the accompanying figures, be located facing each other, either side of the apertures forming communication openings 2' between the internal volumes of said silencer 2 and said intermediate segment 4.

[0018] In particular, if the conduit or pipe consists of a conduit 1 through which the gaseous flow emitted from a turbocompressor of an internal combustion engine passes, it may advantageously be provided that the shapes, the dimensions, the relative dispositions and the degree of acoustic coupling of the multi-hole silencer 2 and the two quarter-wave attenuators 3 and 3' are defined in such a way that the arrangement of acoustic attenuators 2, 3, 3' has an attenuation of at least 20 dB in the 1,500 Hz to 3,200 Hz frequency range.

[0019] The specific definitions of the various components may be calculated using simulation software known to a person skilled in the art.

[0020] The two quarter-wave attenuators 3 and 3' allow attenuation to be reinforced in the region of the extreme values of the frequency range to be attenuated, and will consequently be configured and dimensioned with this object.

[0021] According to one variation of the invention, shown in Figures 5 and 6 of the accompanying drawings, it may be provided that at least the assembly formed by said intermediate segment 4 with the multi-hole silencer 2 and the two quarter-wave attenuators 3 and 3' is formed by joining two single-piece parts 7 and 7', in the region of assembly zones 6 located in the median plane PM of the structure with a flat configuration 5 formed by the aforementioned assembly, containing the central circulation or median X axis of the intermediate rectilinear conduit segment 4, each of the single-piece parts 7, 7' being formed by wall portions of the intermediate segment 4, the multi-hole silencer 2 and two quarter-wave attenuators 3 and 3'.

[0022] According to this variation, any conduit segments and/or additional fittings also forming part of the conduit or pipe 1 may be connected to the opposite ends of the intermediate segment 4 by an appropriate joining technique, after production of the structure 5.

[0023] However, preferably, and according to an alternative to the aforementioned variant, shown in Figure 7 of the accompanying drawings, the conduit or pipe 1 may be formed by joining two constituent parts 8 and 8', each of a single piece, a first part 8 comprising a first tubular fitting 9, optionally a wall portion of a first conduit segment, first wall portions 7 of the multi-hole silencer 2/intermediate segment 4/quarter-wave attenuators 3 and 3' assembly, optionally a wall portion of a third conduit segment 11 and a second tubular fitting 12, and a second part 8' comprising second wall portions 7' of the multi-hole silencer 2/intermediate segment 4/quarter-wave attenuators 3 and 3' assembly, which second wall portions 7' are complementary to the aforementioned first wall portions 7, and, optionally, wall portions 10', 11' complementary to the first and/or third conduit segment(s), the assembly zones 6 of these two constituent parts 8, 8' preferably being located, in the region of the structure 5 with a flat configuration formed by the aforementioned assembly, in the median plane PM of this structure.

[0024] The first and/or the third conduit segment(s) 10 and 10', 11 and 11' may optionally be omitted, the corresponding fitting(s) 9, 12 then being directly contiguous to the intermediate segment 4 (variants not shown).

[0025] In an entirely preferable manner, each of the constituent single-piece parts 7, 7'; 8, 8' is produced by injection-moulding of thermoplastic material(s), optionally filled or reinforced with fibres, and the joining of the two parts 7, 7'; 8, 8' in the region of their assembly zones consists in vibration welding.

[0026] Advantageously, the openings 2' are provided in the common wall portion between the segment 4 and the silencer 2.

[0027] If, alternatively, the openings 2' are provided in a connected plate forming an insert, said plate forming part of the wall portion, common with the silencer 2 and comprising the openings 2', of the intermediate segment 4 is mounted with locking in the corresponding receiving cut-out of this wall portion, in the region of a peripheral groove, and is held by compression between the two parts 7, 7'; 8, 8'.

[0028] The present invention also relates to a method of producing a gaseous fluid circulation conduit or pipe of the above-described type.

[0029] This method is characterised in that it consists in separately producing, by injection moulding, two complementary constituent parts 8 and 8', each of a single piece, i.e. a first part 8 comprising a first tubular fitting 9, optionally a wall portion of a first conduit segment, first wall portions 7 of the multi-hole silencer 2/intermediate segment 4/quarter-wave attenuators 3 and 3' assembly, optionally a wall portion of a third conduit segment 11 and a second tubular fitting 12, and a second part 8' comprising second wall portions 7' of the multi-hole silencer 2/intermediate segment 4/quarter-wave attenuators 3 and 3' assembly, which second wall portions are complementary to the aforementioned first wall portions 7, and, optionally, wall portions 10', 11' complementary to the first and/or third conduit segment(s), and in joining the two complementary constituent parts 8 and 8' by vibration welding, in the region of assembly zones defined by the partition of the walls of the conduit or pipe, the multi-hole silencer 2 and the two quarter-wave attenuators 3 and 3'.

[0030] In a variant, the two parts 7 and 7' may first be produced, then joined into a single structure 5 and, finally, the additional (first and third) conduit segments and the fittings 9 and 12 be connected. This variant of the method will involve additional assembly processes, but will allow greater flexibility with regard to the construction of the final conduit or pipe 1 (possibility of introducing various segments or fittings).

[0031] According to an additional characteristic, the complementary wall portions forming, by cooperation and joining, the rectilinear intermediate segment 4 of the conduit or pipe 1 each comprise a part, preferably half, of the through-openings 2' of the multi-hole silencer 2, these openings 2' being formed during the production of the corresponding constituent part 8, 8', by demoulding in an inclined movement in relation to the principal demoulding axis formed by the direction, perpendicular to the imaginary plane containing the assembly zones 6, of the wall portions 7, 7' of the structure 5 with a substantially flat configuration.

[0032] In a variant, the complementary wall portions forming, by cooperation and joining, the rectilinear intermediate segment 4 may each comprise, in the region of their parts forming, by cooperation, a wall portion common with the multi-hole silencer 2, a cut-out part, these two cut-out parts forming by cooperation, at the moment when the two constituent parts 8 and 8' are joined, a receiving cut-out for a plate or the like comprising openings 2', this plate being mounted in one of said parts 8, 8' prior to assembly and held after assembly in a peripheral groove of the receiving cut-out, by being locked by compression.

[0033] The invention is not of course limited to the embodiment described and illustrated in the accompanying drawings. Modifications are possible, in particular with regard to the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

Claims

1. Gaseous fluid circulation conduit or pipe, provided with an arrangement of acoustic attenuators, extending laterally in the region of an intermediate segment of said conduit or pipe and opening into the interior volume of said segment, characterised in that said arrangement comprises a multi-hole silencer (2) and two quarter-wave attenuators (3 and 3'), said quarter-wave attenuators (3 and 3') being disposed so as to be acoustically coupled to said silencer (2), in that said intermediate segment (4) has a structure substantially rectilinear with a central circulation axis or median axis (X), and in that the multi-hole silencer (2), on the one hand, and the two quarter-wave attenuators (3 and 3'), on the other hand, are located either side of said median axis (X) of said segment (4), so as to form, together with this silencer (2) and these two attenuators (3 and 3'), a single-piece structure (5) with a substantially flat configuration or constitution.

2. Conduit according to claim 1, characterised in that the multi-hole silencer (2) and the two quarter-wave attenuators (3 and 3') have, viewed in lateral elevation in the median plane (PM) of the structure (5) with a flat configuration, formed by the multi-hole silencer (2)/intermediate segment (4)/quarter-wave attenuators (3 and 3') assembly, or in a plane parallel to this median plane, a thickness or an exterior height at most substantially equal to the thickness or the exterior height of the intermediate segment (4), in the direction perpendicular to said median plane (PM), said median plane (PM) containing the central circulation or median axis (X) of said intermediate segment (4).

3. Conduit according to any one of claims 1 and 2, characterised in that the multi-hole silencer (2) consists of a caisson or similar closed hollow body, formed on the wall of the intermediate segment (4) and communicating with the interior volume thereof through a plurality of through-openings (2') provided in said wall, and in that each of the two quarter-wave attenuators (3 and 3') consists of a hollow body in the form of a deformation towards the exterior, forming a cavity in the wall of the intermediate segment (4), the two attenuators (3 and 3') having different dimensions, in particular different depths.

4. Conduit according to claim 3, characterised in that the openings (2') are in the form of through-perforations provided in the wall portion, common with the silencer (2), of the intermediate segment (4), and forming a wall portion contributing to the delimitation of the interior volume of said silencer.

5. Conduit according to claim 3, characterised in that the openings (2') are in the form of through-perforations provided in a plate or the like, made of a metallic or rigid synthetic material, mounted in a cut-out of the wall portion, common with the silencer (2), of the intermediate segment (4), the edges of said plate defining baffle structures with the edges of said cut-out.

6. Conduit according to any one of claims 3 to 5, characterised in that the multi-hole silencer (2) has a parallelepiped, preferably rectangular, shape, and in that each of the quarter-wave attenuators (3 and 3') consists of a cylindrical cavity, with a circular or non-circular section.

7. Conduit according to any one of claims 1 to 6, characterised in that the shapes, the dimensions, the relative dispositions and the degree of acoustic coupling of the multi-hole silencer (2) and the two quarter-wave attenuators (3 and 3') are defined in such a way that the arrangement of acoustic attenuators (2, 3, 3') has an attenuation of at least 20 dB in the 1,500 Hz to 3,200 Hz frequency range.

8. Conduit according to any one of claims 1 to 7, characterised in that at least the assembly formed by said intermediate segment (4) with the multi-hole silencer (2) and the two quarter-wave attenuators (3 and 3') is formed by joining two single-piece parts (7 and 7'), in the region of assembly zones (6) located in the median plane (PM) of the structure with a flat configuration (5) formed by the aforementioned assembly, containing the central circulation or median (X) axis of the intermediate rectilinear conduit segment (4), each of the single-piece parts (7, 7') being formed by wall portions of the intermediate segment (4), the multi-hole silencer (2) and two quarter-wave attenuators (3 and 3').

9. Conduit according to any one of claims 1 to 8, characterised in that it is formed by joining two constituent parts (8 and 8'), each of a single piece, in that a first part (8) comprises a first tubular fitting (9), optionally a wall portion of a first conduit segment, first wall portions (7) of the multi-hole silencer (2)/intermediate segment (4)/quarter-wave attenuators (3 and 3') assembly, optionally a wall portion of a third conduit segment (11) and a second tubular fitting (12), and in that a second part (8') comprises second wall portions (7') of the multi-hole silencer (2)/intermediate segment (4)/quarter-wave attenuators (3 and 3') assembly, which second wall portions (7') are complementary to the aforementioned first wall portions (7), and, optionally, wall portions (10', 11') complementary to the first and/or third conduit segment(s), the assembly zones (6) of these two constituent parts (8, 8') preferably being located, in the region of the structure (5) with a flat configuration formed by the aforementioned assembly, in the median plane (PM) of this structure.

10. Conduit according to any one of claims 8 and 9, characterised in that each of the constituent single-piece parts (7, 7'; 8, 8') is produced by injection-moulding of thermoplastic material(s), optionally filled or reinforced with fibres, and in that the joining of the two parts (7, 7'; 8, 8') in the region of their assembly zones consists in vibration welding.

11. Conduit according to any one of claims 8 and 9, in so far as it relates to claim 5, characterised in that the plate forming part of the wall portion, common with the silencer (2) and comprising the openings (2'), of the intermediate segment (4) is mounted with locking in the corresponding receiving cut-out of this wall portion, in the region of a peripheral groove, and is held by compression between the two parts (7, 7'; 8, 8').

12. Conduit according to any one of claims 1 to 11, characterised in that it consists of a conduit (1) through which the gaseous flow emitted from a turbocompressor of an internal combustion engine passes.

13. Method of producing a gaseous fluid circulation conduit or pipe according to any one of claims 1 to 12, characterised in that it consists in separately producing, by injection moulding, two complementary constituent parts (8 and 8'), each of a single piece, i.e. a first part (8) comprising a first tubular fitting (9), optionally a wall portion of a first conduit segment, first wall portions (7) of the multi-hole silencer (2)/intermediate segment (4)/quarter-wave attenuators (3 and 3') assembly, optionally a wall portion of a third conduit segment (11) and a second tubular fitting (12), and a second part (8') comprising second wall portions (7') of the multi-hole silencer (2)/intermediate segment (4)/quarter-wave attenuators (3 and 3') assembly, which second wall portions are complementary to the aforementioned first wall portions (7), and, optionally, wall portions (10', 11') complementary to the first and/or third conduit segment(s), and in joining the two complementary constituent parts (8 and 8') by vibration welding, in the region of assembly zones defined by the partition of the walls of the conduit or pipe, the multi-hole silencer (2) and the two quarter-wave attenuators (3 and 3').

14. Production method according to claim 13, characterised in that the complementary wall portions forming, by cooperation and joining, the rectilinear intermediate segment (4) of the conduit or pipe (1) each comprise a part, preferably half, of the through-openings (2') of the multi-hole silencer (2), these openings (2') being formed during the production of the corresponding constituent part (8, 8'), by demoulding in an inclined movement in relation to the principal demoulding axis formed by the direction, perpendicular to the imaginary plane containing the assembly zones (6) of the wall portions (7, 7') of the structure (5) with a substantially flat configuration.

15. Production method according to claim 13, characterised in that the complementary wall portions forming, by cooperation and joining, the rectilinear intermediate segment (4) each comprise, in the region of their parts forming, by cooperation, a wall portion common with the multi-hole silencer (2), a cut-out part, these two cut-out parts forming by cooperation, at the moment when the two constituent parts (8 and 8') are joined, a receiving cut-out for a plate or the like comprising openings (2'), this plate being mounted in one of said parts (8, 8') prior to assembly and held after assembly in a peripheral groove of the receiving cut-out, by being locked by compression.

16. Production method according to any one of claims 13 to 15, characterised in that the two constituent parts (8 and 8') comprise, in the region of the assembly zones, complementary indexing cut-outs (13), allowing precise relative positioning of said two parts in relation to each other, before they are joined by vibration welding.

Drawing