COMPONENT OF AN EXHAUST SYSTEM AND METHOD FOR MANUFACTURING SUCH A COMPONENT

Abstract

There is described a component of an exhaust system for an internal combustion engine, which includes a wall in which at least one opening is provided. A perforated cover (16) at least partly closes the opening, wherein the cover (16) is mounted on the wall by means of a holder (18), and a portion (32, 34) of the cover (16) engages into an opening (28, 30) provided on the holder (18). There is also presented an exhaust system comprising such a component, and a method for manufacturing such a component, in which the cover (16) is mounted on the holder (18) by introducing at least one portion (32, 34) of the cover (16) into an opening (28, 30) provided on the holder (18).

Claims

1. A component of an exhaust system for an internal combustion engine, comprising: a wall in which at least one opening is provided; a perforated cover which at least partly closes the opening; and a holder to mount the perforated cover on the wall of the component, and wherein a portion of the perforated cover engages into an opening provided on the holder.

2. The component according to claim 1, wherein at least two portions of the perforated cover each engage into separate openings on the holder.

3. The component according to claim 2, wherein at least one of the two portions of the perforated cover, which engages into an associated opening of the separate openings, is a corner of the perforated cover or a tab of the perforated cover.

4. The component according to claim 1, wherein the holder includes a bearing portion which engages behind the perforated cover in a direction perpendicular to the wall.

5. The component according to claim 1, wherein the holder and the perforated cover are non-cohesively or exclusively positively coupled with each other.

6. The component according to claim 1, wherein the holder is a frame that is mounted on the wall and surrounds the outer edge of the perforated cover.

7. The component according to claim 1, wherein, in a direction perpendicular to the wall, the perforated cover is mounted on the holder substantially without clearance.

8. The component according to claim 1, characterized in that wherein a clearance is provided between the holder and the perforated cover so that the perforated cover is shiftable parallel to the wall of the component.

9. The component according to claim 8, wherein the clearance is formed between an end face of the perforated cover and an abutment surface of the holder opposing the end face at a distance.

10. The component according to claim 9, wherein the holder includes a mounting portion that is mounted on the wall, and a holding portion for the perforated cover that is offset with respect to the mounting portion as seen in a direction perpendicular to the wall, and that the abutment surface is formed by a step at a transition from the mounting portion to the holding portion.

11. The component according to claim 10, wherein an opening or openings that engage portions of the perforated cover is/are provided at the transition from the mounting portion to the holding portion, in particular and wherein the opening or the openings is/are arranged in a corner region of the holder.

12. An exhaust system for an internal combustion engine, comprising the component according to claim 1.

13. A method for manufacturing a component of an exhaust system for an internal combustion engine, comprising the following steps: a) mounting a perforated cover on a holder by introducing at least one portion of the perforated cover into an opening provided on the holder, and subsequently b) attaching an assembly comprising the perforated cover and the holder on a wall so that the perforated cover at least partly closes an opening provided in the wall.

14. The method according to claim 13, wherein, during step a), the perforated cover assumes a bending state for introducing the at least one portion into an associated opening, and in a subsequently assumed relaxation state the perforated cover is exclusively positively mounted on the holder.

15. The method according to claim 13, wherein, during step a), two opposite corners of the perforated cover are each introduced into an associated opening.

16. The component according to claim 2, wherein the at least two portions are arranged on substantially opposite sides of the perforated cover.

17. The component according to claim 2, wherein at least one of the two portions of the perforated cover, which engages into an associated opening of the separate openings, is a corner of the perforated cover and a tab of the perforated cover.

18. The component according to claim 3, wherein all portions of the perforated cover, which engage into associated openings, are corners of the perforated cover or tabs of the perforated cover.

19. The component according to claim 1, wherein the holder and the perforated cover are non-cohesively and exclusively positively coupled with each other.

Description

[0040] FIG. 1 schematically shows a part of an exhaust system comprising to components according to the invention, which have been manufactured by means of a method according to the invention,

[0041] FIG. 2 in a detail view shows an assembly of one of the components of FIG. 1 comprising a cover and a frame in a perspective view,

[0042] FIG. 3 shows the assembly of FIG. 2 in a view from above,

[0043] FIG. 4 shows the assembly of FIG. 2 in a bottom view,

[0044] FIG. 5 shows the frame of the assembly of FIG. 2 in a view corresponding to FIG. 4,

[0045] FIG. 6 shows an alternative to the assembly of FIG. 2 in a schematic bottom view corresponding to FIG. 4,

[0046] FIG. 7 shows another alternative of the assembly of FIG. 2 in a schematic bottom view corresponding to FIG. 4,

[0047] FIG. 8 shows an additional alternative to the assembly of FIG. 2 in a schematic bottom view corresponding to FIG. 4,

[0048] FIG. 9 shows a sectional view corresponding to the sections IX-IX of FIG. 1,

[0049] FIG. 10 shows an enlarged detail X of FIG. 10, wherein the wall is omitted,

[0050] FIG. 11 in a top view shows an assembly of one of the components of FIG. 1 comprising a cover and a frame according to another embodiment, and

[0051] FIG. 12 shows a sectional view corresponding to a section XII-XII of FIG. 12.

[0052] FIG. 1 shows two components 10a, 10b of an exhaust system. The component 10a is a housing, and the component 10b is an exhaust pipe that for example serves to conduct exhaust gas of an internal combustion engine towards an environment.

[0053] In the component 10a configured as a housing, there can be arranged components with which the exhaust gas is treated, for example a catalyst substrate or a particle filter. Alternatively, this can also be the housing of a muffler.

[0054] As far as the components 10a, 10b are arranged at a certain distance from the outlet valves of the internal combustion engine and the temperature of the exhaust gas therefore already has decreased to some extent, a ferritic steel alloy can be used as material for the components 10a, 10b, in particular for their walls 12a, 12b.

[0055] The walls 12a, 12b of the components 10a, 10b each are provided with an opening 14a, 14b. The same can be circular, rectangular, polygonal or oval, for example, and can have a surface area of a few square centimeters.

[0056] In the embodiments of FIG. 1, the openings 14a, 14b each are completely closed with a perforated cover 16a, 16b.

[0057] The perforated covers 16a, 16b each comprise a metal foil or a metal sheet whose wall thickness can be for example 0.3 mm. They are provided with a plurality of small perforations, wherein the proportion of perforations in the entire surface of the cover 16a, 16b lies in the range of 1% to 10%, and preferably of 4% to 8%. A degree of perforation of 6% is particularly preferred.

[0058] The perforations can have a circular shape, a rectangular shape or another geometry. When their open surface is converted into a circular shape, it has a perforation diameter in the order of 0.1 mm to 1.5 mm.

[0059] When the dimensions of the openings are smaller than these values, reference is also made to a microperforated cover 16a, 16b.

[0060] As material for the covers 16a, 16b, there is used an alloy that is resistant to hot-gas corrosion and wet corrosion, such as Inconel. Preferably, an austenitic steel alloy or a suitable ferritic alloy can be used.

[0061] The wall thickness of the cover 16a, 16b lies below 1 mm and in particular in the order of 0.3 mm.

[0062] These values apply for the initial sheet. With regard to cutting or shaping manufacturing methods, as they can be used for manufacturing the cover, the cover possibly is “thicker” after machining, in case the distance of the surface tips is measured, as burrs may be obtained.

[0063] The perforated covers 16a, 16b each are attached to the associated wall 12a, 12b by means of an associated holder 18a, 18b.

[0064] The same is configured as a frame and is made of sheet metal. Preferably, the material used is a ferritic steel alloy, in particular a steel alloy with the same thermal expansion behavior as the associated component 10a, 10b, more exactly the associated wall 12a, 12b.

[0065] For the following detailed description of the components 10a, 10b no more distinction is made between the two embodiments shown in FIG. 1. Therefore, the reference numerals partly are also used without the suffixes “a” and “b”. The explanations equally apply for the components 10a and 10b.

[0066] The holder 18 includes a circumferential mounting portion 20 that is provided to be attached to the associated wall 12a, 12b. Within the circumferential mounting portion 20 a holding portion 22 is provided. The same forms the inner edge of the holder 18 and defines a cutout 24 that has a similar size as the respectively associated opening 14a, 14b. The cutout hence can be slightly larger than the respectively associated opening 14a, 14b, slightly smaller or substantially the same size.

[0067] As can be seen in particular in FIG. 10, the holding portion 22 is offset with respect to the mounting portion 20 in a direction perpendicular to the mounting portion 20 and hence also perpendicular to the wall 12a, 12b. The offset nominally at least amounts to the thickness of the perforated cover 16. It may occur that the offset within the range of the permitted tolerances also is smaller than the thickness of the perforated cover 16. However, this does not preclude the intended function of the component 10a, 10b.

[0068] The offset between the holding portion 22 and the mounting portion 20 can be achieved by suitably embossing and/or stamping a flat sheet metal blank of the holder 18.

[0069] The holding portion 22 in addition defines a receptacle for the cover 16 that can be arranged in this receptacle. The dimensions of the cover 16 are chosen such that the same is slightly smaller than the receptacle. Expressed in other words, a minor clearance s remains between the end faces of the cover 16 and a step 26 that is formed at the transition between the holding portion 22 and the mounting portion 20. This clearance s lies in the range of 0.2 to 4 mm.

[0070] When the holder 18 is mounted on the associated component 10a, 10b, the perforated cover 16 below the holding portion 22 can “travel” parallel to the wall of the component 10a, 10b due to the clearance s, namely until it each abuts against the step 26 that acts as an abutment surface on the holder 18 for the cover 16.

[0071] In addition, two mutually opposite openings 28, 30 each are provided on the holder 18 of the embodiment of FIGS. 2 to 5.

[0072] An associated portion 32, 34 of the cover 16 engages into each of the openings 28, 30.

[0073] In the embodiment of FIGS. 2 to 5, the cover 16 correspondingly includes two portions 32, 34 which are arranged on opposite sides of the cover 16.

[0074] The portions 32, 34 are corners of the cover 16.

[0075] Correspondingly, the associated openings 28, 30 are arranged in corner regions of the holder 18. Furthermore, the openings 28, 30 are located at the transition from the mounting portion 20 to the holding portion 22.

[0076] In the embodiments of FIGS. 6 to 8, in contrast to the embodiment of FIGS. 2 to 5, the portions 32, 34 of the cover 16 are designed as adjacent corners. This results in a corresponding position of the openings 28, 30.

[0077] In the embodiment of FIGS. 6 and 7, the portions 32, 34 are adjacent along a short edge of the rectangular cover 26.

[0078] In the embodiment of FIG. 7, the holder 18 additionally includes a bearing portion 36 that engages behind the cover 16 in a direction perpendicular to the wall 12a, 12b.

[0079] In the illustrated embodiment, the bearing portion 36 is configured as a substantially rectangular tab and is arranged on an inside of the holder 18. It extends substantially in the same plane as the mounting portion 20. The cover 16 hence is arranged in the region of the bearing portion 36 between the same and the holding portion 22.

[0080] In the embodiment of FIG. 8, the portions 32, 34 are adjacent along the long edge of the rectangular cover 16.

[0081] The cover 16 and the holder 18 can be dimensioned such that the cover 16 in a substantially flat state of the assembly comprising the cover 16 and the holder 18 rests against the holder with its edge 38 shown at the bottom in FIG. 8. In particular, the edge 38 rests against the holder 18 under a certain tension.

[0082] Only when the assembly comprising the holder 18 and the cover 16 is slightly bent while being mounted on the wall 12a, 12b, a certain clearance is obtained between the holder 18 and the cover 16 in the vertical direction in FIG. 8.

[0083] In the embodiment of FIGS. 11 and 12, which differs from the aforementioned embodiments merely by the design of the portions 32, 34 and the associated openings 28, 30, the portions 32, 34 are formed by tabs of the cover 16. The Figures merely show the portion 32.

[0084] In all embodiments, the cover 16 is positively and non-cohesively coupled with the holder 18 via the portions 32, 34. The cover 16 and the holder 18 thus form an assembly and can jointly be attached to the associated wall 12a, 12b.

[0085] The coupling between the cover 16 and the holder 18 is designed such that the cover 16 is mounted on the holder 18 substantially without clearance in a direction perpendicular to the wall 12. As explained already, the coupling in directions transverse thereto is subject to a certain clearance.

[0086] By means of its mounting portion 20, the holder 18 is firmly mounted on the associated wall 12a, 12b. In the illustrated exemplary embodiment, the mounting portion is welded to the wall 12a, 12b.

[0087] The manufacture of the components 10a, 10b proceeds as follows.

[0088] First, the cover 16 is mounted on the associated holder 18 by introducing at least one of the portions 32, 34 of the cover 16 into the associated opening 28, 30.

[0089] Hence, in the embodiments of FIGS. 2 to 7 the corners of the cover 16 are introduced into the openings 28, 30, and in the embodiments of FIGS. 8 and 9 the portion 32 configured as a tab is introduced into the opening 30.

[0090] To introduce the portions 32, 34 into the associated openings 28, 30, the cover 16 can be transferred into a bending state by applying a corresponding force on the cover 16. This can be done by hand.

[0091] The portions 32, 34 then are each positioned at the entrance of the associated opening 28, 30. The cover 16 then is relieved with regard to the force so that the same passes into a relaxation state in which the cover 16 is flat or planar as compared to the bending state. In the process, the portions 32, 34 are introduced into the openings 28, 30. As mentioned already, it is merely important that the cover 16 is flat or planar as compared to the bending state. It is very well possible that in this state the cover 16 still has a certain bend which for example corresponds to the contour of the holder 18 or the wall 12a, 12b.

[0092] Thus, the cover 16 is positively mounted on the holder 18, and the cover 16 and the holder 18 form an assembly.

[0093] Subsequently, this assembly is arranged on an associated wall 12a, 12b in such a way that it closes the opening 14.