Silencer

Abstract

A silencer, for example an intake silencer for an internal combustion engine, may include a pipe for conducting a gas mixture. The pipe may be perforated at least in some regions. An absorption layer may at least partially surround the pipe for absorbing a sound transmitted by the gas mixture. An outer casing may encase the pipe. The outer casing may be perforated at least in some regions and may surround the absorption layer.

Claims

1. A production method for a silencer, comprising: providing a pipe having a perforated region and a perforated connection region; providing a first half shell and a second half shell, wherein at least one of the first half shell and the second half shell has a perforated region; disposing a hollow connecting element on the first half shell to provide a fluidic connector for communicating fluid in the pipe, the hollow connecting element having an axis extending through the perforated connection region pressing a porous sound-absorbing material between the pipe and at least one of the first half shell and the second half shell to form an absorption layer sandwiched between the perforated region of the pipe and the perforated region of the at least one of the first half shell and the second half shell; joining the first half shell and the second half shell together to form an outer casing enclosing the pipe and surrounding the absorption layer; wherein the perforated connection region defines a fluidic connection between the pipe and the hollow connecting element.

2. The method according to claim 1, wherein providing the pipe includes disposing a configuration of perforation holes in the perforated region and another configuration of perforation holes in the perforated connection region, the other configuration of perforation holes in the perforated connection region structured differently than the configuration of perforation holes in the perforated region to facilitate fluid communication between the hollow connecting element and the pipe.

3. A silencer, comprising: a pipe having an axis for conducting a gas mixture, wherein the pipe is perforated with a plurality of perforation holes in at least one region; an absorption layer at least partially surrounding the pipe for absorbing a sound transmitted by the gas mixture; an outer casing at least partially encasing the pipe, wherein the outer casing is perforated with a plurality of perforation holes in at least one region and the outer casing surrounds the absorption layer; and a fluidic connector to provide a fluid coupling for the pipe, wherein the fluidic connector includes at least one hollow connecting element disposed on the pipe and in fluid communication with the gas mixture.

4. The silencer according to claim 3, wherein the pipe has at least one perforated connection region defining a fluidic connection between the pipe and the at least one hollow connecting element, and wherein the at least one perforated connection region includes a plurality of other perforation holes having a flow cross-section sized larger than that of the plurality of perforation holes in the at least one region of the pipe to facilitate a fluid flow through the at least one perforated connection region.

5. The silencer according to claim 3, wherein the plurality of perforation holes of the pipe and the plurality of perforation holes of the outer casing are arranged partially offset to one another in a radial direction of the pipe.

6. The silencer according to claim 3, wherein the absorption layer is composed of a material capable of substantially completely absorbing the sound in a high frequency range.

7. The silencer according to claim 3, wherein the pipe is perforated in a configuration facilitating a change in a buildup of resonant frequencies and a reduction of an outlet sound in low frequency ranges, and wherein the configuration includes at least one of: a uniform distribution of the plurality of perforation holes disposed in the pipe; the plurality of perforation holes disposed in the pipe have a round shape; and at least two of the plurality of perforation holes disposed in the pipe have the same shape.

8. The silencer according to claim 3, further comprising an acoustic resonator coupled to the at least one connecting element for influencing the sound transmitted by the gas mixture, wherein the acoustic resonator is arranged transverse to a flow direction of the gas mixture in the pipe and spaced apart from the pipe and the outer casing.

9. The silencer according to claim 3, wherein the at least one connecting element has a hollow-cylindrical structure and projects radially from the pipe.

10. The silencer according to claim 9, wherein the at least one connecting element has an axis that extends substantially perpendicular to a flow direction of the gas mixture in the pipe.

11. The silencer according to claim 9, wherein the at least one connecting element is a first connecting element, and wherein the fluidic connector further includes a hollow-cylindrical second connecting element in fluid communication with the gas mixture and arranged axially parallel to the first connecting element.

12. The silencer according to claim 11, wherein the first connecting element and the second connecting element are arranged spaced apart transverse to a flow direction of the gas mixture in the pipe.

13. The silencer according to claim 11, wherein the pipe has a first connecting region fluidically connected to the first connecting element and a second connecting region fluidically connected to the second connecting element.

14. The silencer according to claim 13, wherein at least one of the first connecting region and the second connecting region is perforated with a plurality of other perforation holes.

15. The silencer according to claim 14, wherein the plurality of other perforation holes of the at least one of the first connecting region and the second connecting region are structured differently from the plurality of perforation holes disposed in the at least one region of the pipe.

16. The silencer according to claim 14, wherein the at least one of the first connecting region and the second connection region is arranged in a bent section of the pipe to facilitate a flow of the gas mixture therethrough.

17. The silencer according to claim 15, wherein the plurality of other perforation holes are different in at least one of number, density and size than the plurality of perforation holes disposed in the at least one region of the pipe.

18. A silencer for an engine intake, comprising: a pipe for conducting a fluid flow, the pipe having at least one perforated region including a plurality of perforation holes; an absorption layer at least partially surrounding the pipe in the at least one perforated region for absorbing a sound transmitted by the fluid flow, the absorption layer composed of a porous sound-absorbing material; an outer casing at least partially encasing the pipe and surrounding the absorption layer, the outer casing having at least one perforated region including a plurality of perforation holes; wherein the absorption layer is sandwiched between the at least one perforated region of the pipe and the at least one perforated region of the outer casing; and wherein the pipe has at least one perforated connection region to provide a fluidic connection for the pipe, the at least one perforated connection region including a plurality of other perforation holes structured differently from the plurality of perforation holes of the at least one perforated region of the pipe.

19. The silencer according to claim 18, further comprising a fluidic connector to provide a fluid coupling for the pipe, wherein the fluidic connector includes at least one hollow connecting element fluidly connected to the at least one perforated connection region, the at least one perforated connection region defining the fluidic connection between the pipe and the at least one hollow connecting element, and wherein the at least one hollow connecting element projects from the outer casing transverse to a flow direction of the fluid flow.

20. The silencer according to claim 18, wherein at least some of the plurality of other perforation holes of the at least one perforated connection region have a flow cross-section sized larger than the plurality of perforation holes of the at least one perforated region of the pipe to facilitate communicating the fluid flow through the at least one perforated connection region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures, schematically

(2) FIG. 1 shows a cross-section of a silencer according to a first embodiment of the invention,

(3) FIG. 2 shows a view of an intake system with a silencer according to a second embodiment of the invention,

(4) FIG. 3 shows a partial perspective view of the silencer of FIG. 2,

(5) FIG. 4 shows another partial perspective view of the silencer of FIG. 2, and

(6) FIG. 5 shows a spatial view of a section through the silencer.

DETAILED DESCRIPTION

(7) FIG. 1 illustrates a silencer 10 according to a first embodiment according to the invention by means of a sectional view. The term silencer in the present context is to be understood as any device for reducing sound emissions, which comprises in particular intake silencers in motor vehicles in addition to mufflers for reducing exhaust noises. However, so-called cross-talk sound attenuators or splitters as those used in building technology in ventilation ducts or air-conducting channel systems are principally also to be understood as silencers.

(8) The core of the silencer 10 is formed by a pipe 11, the cross-section of which corresponds approximately to a rounded rectangle. The walls of the pipe 11 are composed of a substantially fluid-tight material which is particularly suitable for conveying air. Further (non-illustrated) molded pipes, expansion joints, valves, seals, connecting elements such as flanges, fittings, screw connectors, sockets and fastener elements for support may supplement the pipe 11 in a known arrangement.

(9) As can be seen from the longitudinal section of FIG. 1, the pipe 11 is surrounded on two sides along a subsection by an absorption layer 12 which is formed by two acoustic panels embedded in opposing wall surfaces of the pipe 11. Alternatively, a circumferentially arranged absorption layer 12 applied on the outside is also conceivable. In this case, a porous sound-absorbing material with through-pores, for example, a suitable melamine resin foam or another foam, serves as an absorber. Foam, in a broad literal sense, is to be understood as any material having a cell structure and low density which is produced in a substantially artificial manner. Likewise, included are in particular chemically, physically or mechanically foamed materials which are well known to the person skilled in the art and which are used in the field of plastics processing.

(10) The absorption layer 12, for its part, is surrounded by an outer casing 13 which presses the foam against the inner pipe 11 and fixes the foam in its position. The pipe 11 as well as the outer casing 13 is perforated in such a manner that their respective perforation holes 32 are slightly offset to one another in the radial direction of the pipe 11. Apart from that, the arrangement, quantity, shape and size of the perforation holes 32 are selected such that they provide the silencer 10 with a higher absorption degree with respect to lower audible sound frequencies.

(11) In the example shown, a uniform distribution of perforation holes 32 can be seen in each case on the outer casing 13 and the pipe 11. The respective perforation hole 32 can have a size or a diameter of approx. 2 mm.

(12) FIGS. 2, 3 and 4 show a second embodiment according to the invention of a silencer 20, which now functions as an intake silencer that is part of an intake system 24 for an internal combustion engine in the form of a diesel engine. For this purpose, the intake silencer 20 can be connected to the combustion chambers of cylinders of the diesel engine, for example via an optionally controllable intake line, and can supply the fresh gas needed for the combustion process to said combustion chambers. For additional damping of the intake noises and for cleaning of the raw intake air, the intake silencer 20 can also be equipped with a suitable air filter (not illustrated) in the form of a paper filter or dry air filter, a wet air filter or oil bath filter, which potentially reduces wear on the piston, piston rings, cylinder running surfaces and bearings of the diesel engine. In an alternative embodiment, which is not shown, in which the silencer according to the invention is used in connection with a gasoline engine, the intake system 24 can include additional components for preheating the intake air and for the injection of fuel, for example by means of a mechanically or electromagnetically actuated injection valve.

(13) Furthermore, in the present embodiment, two pipe-shaped connecting elements 28, 29, which are aligned axially parallel, are formed on the pipe 21 of the intake silencer 20. Due to their hollow-cylindrical shape and their specific arrangement, these connecting elements 28, 29 add to the intake silencer 20 a fluidic connector 25 for an acoustic resonator 26 (shown only in FIG. 2), which can establish a plug connection with the intake silencer 20 via a corresponding mating connector.

(14) The resonator 26 is arranged spaced apart from the pipe 21 and the outer casing 23 and is oriented transverse to the flow direction of the gas mixture in the pipe 21.

(15) In the view according to FIG. 3, the production method used for manufacturing the intake silencer 20 becomes apparent. Thus, it becomes clear that the outer casing 23 is formed by the combination of two half shells 33, 34 which are joined together along a flange and between which the sound-absorbing material, which is covered in FIG. 3 by the outer casing 23, is pressed against the pipe 21. The pipe 21 can also be implemented as a half shell construction formed from two substantially identically shaped modules 35, wherein optional spacers to be inserted between the half shells 33, 34 allow adapting the intake silencer 20 to absorption layers of different thicknesses.

(16) FIG. 5 shows a section through such a silencer 10, 20. Shown here is the first half shell 33 for fabricating the outer casing 23, which comprises the first connecting element 28 and the second connecting element 29, which are integrally molded on the first half shell 33 and therefore are integrally molded on the silencer 20. Also, shown is such a half-shell-like module 35 for fabricating the pipe 21, which, together with a half-shell-like second module, which is not shown here, forms the pipe 21.

(17) The fluidic connection between the first connecting element 28 and the pipe 11 is implemented via a first connecting region 30 of the first module 35 and thus of the pipe 21. The same applies to the second connecting element 29 which is fluidically connected to the pipe 21 via a second connecting region 31 of the first module 35 or the pipe 21. Due to the cylindrical shape of the connecting elements 28, 29, the connecting regions 30, 31 are circular in a top view in the direction of the axis of the associated connecting element 28, 29.

(18) The first connecting region 30 and the second connecting region 31 are at least partially bent. This means that the connecting regions 30, 31 are arranged in a bent section of the first module 35 or the pipe 21. Here, this bend is implemented by forming the first module 35 in such a manner that it is convex with respect to the connecting elements 28, 29. This means that the first module 35 and/or the pipe 21 in the respective connecting region 30, 31 is bent towards the associated connecting element 30, 31.

(19) Furthermore, it can be seen in FIG. 5 that the connecting regions 30, 31 are perforated. The connecting regions 30, 31 are perforated differently from other perforated regions of the pipe 21. In the example shown, this other perforation is implemented by forming larger perforation holes 32 in the connecting regions 30, 31.

(20) It can be seen in the FIGS. 2 to 5 that the connecting elements 28, 29 are arranged spaced apart. Accordingly, the connecting regions 30, 31 are also spaced apart. The connecting elements 28, 29 are arranged spaced apart or offset transverse to the flow direction of the gas mixture in the pipe 11, 21. Moreover, it can be seen that the alignment of the connecting elements 28, runs transverse to the flow direction of the gas mixture in the pipe 21. This means that the connecting elements 28, 29 project transverse to the flow direction from the silencer 20.