muffler

Abstract

The invention relates to a muffler for an exhaust system of an internal combustion engine, comprising at least one muffler component (30) having a perforation (42) comprising a plurality of flow-through openings (44) in a wall (40) of the muffler component (30), the flow-through openings (44) being flowable in a flow direction (S) in a direction from an upstream side (54) of the wall (40) towards a downstream side (58) of the wall (40), the flow-through opening flow cross section (D) decreasing in the flow direction (S) at least in a portion of the flow-through openings (44) of the perforation (42), preferably in all flow-through openings (44) of the perforation, for providing a flow-through opening flow guide surface (50).

Description

Technical Field

[0001] The present invention relates to a muffler, which can be used, for example, in the exhaust system of an internal combustion engine, to reduce noise generated during the operation of the internal combustion engine. Background Technology

[0002] Such a muffler, which can be installed in the exhaust system of an internal combustion engine, typically includes an outer wall surrounding the internal space of the muffler. Inside the muffler space, exhaust gas ejected from the internal combustion engine is guided through one or more exhaust guide pipes, each providing muffler components. Further, one or more partition walls providing muffler components may be provided within the internal space of the muffler, separating muffler chambers that perform different functions from each other, for example.

[0003] In order to place different volumetric regions within the muffler's internal space in flow connections, perforations can be constructed in one or more muffler components, such as one or more exhaust guides and / or one or more partition walls. These perforations have multiple, typically relatively small, and closely spaced flow-through openings. These flow-through openings allow for direct penetration of exhaust gas and do not provide for accommodating exhaust guides, for example, in the design of the partition walls, so that these exhaust guides are joined to such partition walls and that exhaust gas guided through such exhaust guides is also guided through the partition walls. Through these flow-through openings of the perforations, exhaust gas can flow, for example, from a volume formed within the exhaust guide to a volume surrounding the exhaust guide, or, when such perforations are constructed in partition walls, exhaust gas can flow from one of two chambers separated by the partition wall to the other of the two chambers separated by the partition wall. Summary of the Invention

[0004] The objective of this invention is to provide a muffler for an exhaust system of an internal combustion engine, wherein the muffler achieves improved flow guidance in order to improve noise reduction characteristics.

[0005] According to the invention, the task is solved by a muffler for an exhaust system of an internal combustion engine, the muffler comprising at least one muffler component having a perforation in the wall of the muffler component including a plurality of flow-through openings, wherein the flow-through openings are capable of flowing in a direction from an upstream side of the wall toward a downstream side of the wall, and at least in a portion of the flow-through openings of the perforation, preferably in all the flow-through openings of the perforation, the flow cross-section of the flow-through openings decreases in the flow direction to provide a flow-through opening guide surface.

[0006] By providing guide surfaces in the flow-through openings of the muffler components, where the flow cross-section decreases along the flow direction, exhaust gas ejected from the internal combustion engine is guided from the region of the larger flow cross-section of the corresponding flow-through opening to the region of the smaller flow cross-section. As a result, the vortices formed in the exhaust flow are reduced in the region of the flow-through opening, which on the one hand helps to reduce flow resistance, and on the other hand helps to reduce noise formation when passing through such openings.

[0007] To optimize flow guidance, the cross-sectional area of ​​the flow-through opening can be gradually reduced along the flow direction.

[0008] This can be achieved, for example, by reducing the cross-sectional profile of the flow through the opening with a rounded cross-sectional change profile. To avoid the formation of vortices, a particularly advantageous design is one in which the cross-sectional profile of the flow through the opening is reduced with a substantially edgeless cross-sectional change profile.

[0009] In order to avoid the formation of eddies in the connection on the upstream side of the wall of the corresponding flow-through opening guide surface of the muffler component, it is proposed that the flow-through opening guide surface be connected to the upstream side of the wall substantially without sharp edges.

[0010] The flow cross-section of the flow-through opening can, for example, be reduced in the first flow-through opening-opening length region corresponding to the wall thickness between the upstream and downstream sides of the wall.

[0011] The strong guiding characteristics of the flow-through opening can be achieved, for example, by providing a flow-through shoulder that extends downstream from the downstream side of the wall and annularly surrounds the corresponding flow-through opening in the second flow-through opening-opening length region, in a manner that matches at least a portion, preferably all, of the flow-through openings. In at least a portion, preferably all, of the flow-through shoulders, the flow-through opening cross-section of each flow-through opening surrounded by one of the flow-through shoulders can be reduced in the second flow-through opening-opening length region.

[0012] In order to achieve a gradual reduction in the flow cross-section of the flow through the opening, the flow cross-section of the flow through the opening can be reduced more significantly in the first flow through opening-opening length region than in the second flow through opening-opening length region.

[0013] In order to effectively avoid flow eddies in the region of the flow-through opening, the inclination angle of the flow-through opening guide surface about the opening center axis can be in the range of 5° to 15° in the region of the outlet end of the corresponding flow-through opening.

[0014] The at least one muffler component can be configured, for example, as an exhaust guide pipe. When multiple exhaust guide pipes are provided in a muffler, a perforation with a flow-through opening, according to the structure of the invention, can be provided in only one or some of the exhaust guide pipes, or in each of the exhaust guide pipes. Alternatively or additionally, the at least one muffler component can be configured as a partition wall separating two muffler cavities from each other. Here, when multiple partition walls are provided in a muffler, a perforation with a flow-through opening, according to the structure of the invention, can also be provided in one or some of the partition walls, or in each of the partition walls.

[0015] Furthermore, the present invention relates to an exhaust device for an internal combustion engine, the exhaust device comprising at least one muffler constructed according to the present invention.

[0016] Furthermore, the present invention relates to a method for manufacturing a muffler having the previously described structure, characterized in that:

[0017] The at least one muffler component is constructed of a metallic material, and channels are formed in the wall of the muffler component to provide the flow-through opening guide surface.

[0018] or

[0019] The at least one muffler component is constructed as a plastic molded part, and the flow-through opening guide surface is formed into the wall of the muffler component. Attached Figure Description

[0020] The present invention will now be described in detail with reference to the accompanying drawings. In the drawings:

[0021] Figure 1 The muffler of the exhaust system of an internal combustion engine is shown, the muffler having a partially opened muffler housing shown;

[0022] Figure 2 It shows that it can be used as an example Figure 1 A perspective view of the exhaust guide pipe used in the muffler components of the muffler;

[0023] Figure 3 It shows that it can be used as an example Figure 1 A perspective view of the partition wall used in the muffler components of the muffler;

[0024] Figure 4 It shows that it can be used as an example Figure 1 A partial longitudinal section view of the exhaust guide pipe used in the muffler component of the muffler;

[0025] Figure 5 Show Figure 4 A magnified view of the detail V in the image;

[0026] Figure 6 This illustrates an alternative design for a muffler component. Figure 5 The illustration. Detailed Implementation

[0027] exist Figure 1 The diagram exemplarily illustrates a muffler, generally designated 10, for an exhaust system 12 of an internal combustion engine. The muffler 10 includes a muffler housing 14, which, in the illustrated example, includes a substantially cylindrical circumferential wall 16 and two end walls 18, 20 disposed at the axial ends of said circumferential wall. A partition wall 22 is provided inside the muffler housing 14, dividing the muffler's internal space 24 into two chambers 26, 28.

[0028] In chamber 26, an exhaust guide pipe 32 providing the muffler component 30 extends between end wall 18 and partition wall 22. The exhaust guide pipe 32 may be closed by partition wall 22 in its end region where it connects to partition wall 22, or it may be as follows: Figure 3 The partition wall 22 shown in the figure is open relative to the opening 34, which is constructed as a channel in the partition wall 22, and thus relative to the chamber 28.

[0029] An exhaust guide 36, providing another muffler component 30, extends within chamber 24, opening relative to chamber 26 in its end region connected to partition wall 22 via, for example, an opening 38 formed in a passage within partition wall 22. Exhaust guide 32 may, for example, serve as an inlet pipe for muffler 10 or be connected to the inlet pipe in a region of end wall 18. Exhaust guide 36 may serve as an outlet pipe for muffler 10 or be connected to the inlet pipe in a region of end wall 20. If in Figure 1 In the muffler 10 shown exemplarily, the exhaust guide pipe 32 is closed by the partition wall 22 in its end region where it connects to the partition wall 22. Exhaust A, entering the muffler via the exhaust guide pipe 12, reaches the chamber 26 via the perforation 42 and then the exhaust guide pipe 36, through which exhaust A exits the muffler 10. Here, the chamber 28 can function for silencing in the form of a resonator chamber. If the exhaust guide pipe 32 is designed in such a way as the partition wall 22... Figure 3 As shown, the exhaust gas A entering the exhaust guide pipe 32 is open relative to the chamber 28 via the opening 34 in the partition wall 22, and can enter the exhaust guide pipe 36 via the perforation 42 in the exhaust guide pipe 32 and the chamber 26, and also via the perforation 42 in the chamber 28 and the exhaust guide pipe 36, and is discharged from the muffler 10 via the exhaust guide pipe.

[0030] It should be pointed out that: regarding Figure 1 The following explanation focuses on the exemplary construction of a very simple, structurally-based muffler 10, specifically concerning key system areas of such a muffler. It goes without saying that in the muffler housing of such a muffler, multiple chambers can be constructed to be separated from each other by corresponding partition walls, and more than two exhaust guide pipes, as shown, can be provided to guide exhaust gas flowing through the muffler in a defined manner and method through the muffler and the chambers constructed therein.

[0031] Figure 2 For example, illustrated by means of an exhaust guide 32 providing a muffler component 30, perforations generally indicated by 42, having a plurality of flow openings 44, can be constructed in the wall 40 of the exhaust guide 32. Correspondingly, for example, such perforations can also be constructed in the wall of the exhaust guide 36 or in the partition wall 22. Figure 3 The perforation 42 shown in the figure has a plurality of relatively small, defined, and closely spaced flow openings 44 through which the exhaust gas of the flow muffler 10 can flow.

[0032] The following is about Figure 4 and Figure 5 The structure of the perforation 42, or the flow opening 44 of the perforation, will be explained in detail. It should be noted that the perforation with such a structured flow opening can be provided not only in the wall of the muffler component configured as an exhaust guide pipe, but also in the wall of the muffler component configured as a partition wall.

[0033] These figures, for example, illustrate how the structure of the flow-through opening 44 coordinates with the flow guidance in the muffler 10, using the exhaust guide 32 that provides the muffler component 30. Specifically, it can be seen that in the exhaust guide 32, exhaust gas A, ejected from the internal combustion engine and flowing towards the muffler 10 in the exhaust device 12, enters a volume 48 surrounded by the wall 40 of the exhaust guide 32 and can flow into chamber 26 through perforations 42 formed in the wall 44, or flow-through openings 44 of the perforations, in the illustrated example. Here, in the region of each flow-through opening 44, exhaust gas A flows substantially along the flow direction S from the volume 48 into chamber 26, which can roughly correspond to the extension direction of the opening center axis O of the flow-through opening 44. Considering that exhaust gas A flows through the volume 48 in the exhaust guide 32 in principle along the direction of the pipe longitudinal axis R, the flow direction S can be positioned along the direction of the pipe longitudinal axis R with respect to the extension direction of the opening center axis O of the corresponding flow-through opening 44.

[0034] exist Figure 5 As can be seen from the diagram: Preferably, each flow-through opening 44 is configured such that, along the flow direction S, or in other words, along the direction of the opening's central axis O, in... Figure 5The flow cross-section D, illustrated by the opening diameter, decreases along the flow direction S and provides a corresponding flow-through opening guide surface 50 with a cross-sectional variation profile. In the illustrated example, the flow-through opening guide surface 50 formed in the region of each flow-through opening 44 is connected to the upstream side 54 of the inner surface 52 of the wall 40 that provides the exhaust guide 32 with essentially no edge-like or stepped transition and provides a generally rounded, edgeless cross-sectional variation profile.

[0035] In the preferred region of each flow-through opening 44, a flow-through shoulder 60 is constructed, protruding downstream of the wall 40 of the exhaust guide 32, providing a downstream side 58 of the outer peripheral surface 56. If the exhaust guide 32 is a metal component, for example, constructed from sheet metal, the flow-through shoulder 60 in the region of the flow-through opening 44 can serve as a channel formed during the forming of the metal blank using a corresponding molding die. If the exhaust guide 32 is a plastic molded part, for example, manufactured in a die-casting or deep-drawing process, the flow-through shoulder 60 can be formed onto the exhaust guide 32 during the die-casting process using a corresponding shape.

[0036] By providing a flow-through shoulder 60, a flow-through opening 44 is formed having two successive flow-through opening-opening length regions L1 and L2 along the flow direction S. The first flow-through opening-opening length region L1 substantially corresponds to an extension section of the corresponding flow-through opening 44, which corresponds to the wall thickness W of the wall 40 of the exhaust guide pipe 32. The second flow-through opening-opening length region L2, which then follows along the flow direction S, corresponds to an extension section in which the corresponding flow-through shoulder 60 protrudes outwardly from the downstream side 58 of the wall 40.

[0037] In the illustrated design example, the corresponding flow-through opening guide surface 50 is rounded along the flow direction S, and thus the flow-through opening flow cross-section D of the flow-through opening 44, i.e., the diameter in a circular design, decreases progressively along the flow direction S, i.e., substantially along the direction of the opening's central axis O. This flow-through opening flow cross-section D changes more strongly in the first flow-through opening-opening length region L1 than in the second flow-through opening-opening length region L2. Because the flow-through opening-opening cross-section D changes, i.e. decreases, along the flow direction S over the entire extension of the corresponding flow-through opening 44, a relatively large radius of curvature for the flow-through opening guide surface 50 can be provided by setting the flow-through shoulder 60 and the corresponding flow-through opening 44 along the flow direction S, thus providing a relatively large extension length relative to the wall thickness W. This allows the exhaust gas A of the flow-through volume 48, flowing radially outward through the flow-through opening 44 about the longitudinal axis R of the exhaust guide pipe 32, approximately along the flow direction S, to be introduced relatively gently and without forming significant turbulence into the flow-through opening 44. Therefore, a significantly reduced flow resistance can be achieved when exhaust A penetrates through the perforation 42 compared to a transition from the upstream side 54 to the flow opening 44, for example, a sharp angle, and the risk of noise formation in this transition region through eddies can be significantly reduced.

[0038] exist Figure 5 As can be seen with the aid of tangent T, due to the flow-through shoulder 60 provided in conjunction with the flow-through opening 44 of the perforation 42, the flow-through opening guide surface 50, which extends and bends along the flow direction S, or in the direction of the opening center axis O of the corresponding flow-through opening 44, is almost parallel to the opening center axis O in the region of the outlet end 46 of the corresponding flow-through opening 44, or at a relatively small angle within the range of 5° to 15°. This helps to reduce vortices in the exhaust flow, especially in the region of the outlet end 46 of the flow-through opening 44.

[0039] exist Figure 6 The image illustrates, for example, an alternative design of the muffler component 30 using an exhaust guide 32. In this design, no through-flow shoulder protruding downstream 58 is provided on the wall 40 of the exhaust guide 32. This means that the extension length of the through-flow opening 44 along the flow direction S substantially corresponds to the extension length of the first through-flow opening-opening length region L1 corresponding to the wall thickness W of the wall 40. In such a design, the through-flow opening 44 can also be provided with a flow cross-section D that decreases along the flow direction S and, for example, a rounded through-flow opening guide surface 50. Figure 5 and Figure 6 The comparison clearly shows that: in the basically the same orientation of the flow guide surface 50 of the first flow opening-opening length region L1, i.e., the cross-sectional change profile, the tangent T on the outlet end 46 of the corresponding flow opening 44 is in accordance with... Figure 6 In the design scheme, compared to Figure 5 In the design scheme of having a flow-through shoulder 60 in the flow-through opening 44, the opening center axis O is strongly bent.

[0040] The muffler component 30 in Figure 6 The variant shown can be particularly advantageously specified in the case where the muffler component is manufactured as a plastic molded part, for example, in a die-casting process, in which the flow-through opening 44 and the flow-through opening guide surface 50 surrounding the flow-through opening are generated by the corresponding molding of the molded part.

[0041] It should be noted that the principles of the present invention can also be used when the flow-through openings 44 are provided in a different configuration. For example, these flow-through openings may be constructed as elongated orifice-shaped openings through which exhaust gas A flows and surrounded by corresponding flow-through opening guide surfaces 50. It may also be specified that the radius of curvature of the flow-through opening guide surfaces 50 is changed. For example, it is possible that the radius of curvature is larger in the adjacent region on the upstream side 54 than in the region adjacent to the downstream side 58, or in other words, than in the second flow-through opening-opening length region L2 formed in the corresponding flow-through shoulder 60.

[0042] It should also be noted that, depending on the flow direction, in the tubular design of the muffler component, the flow-through opening can also be provided to introduce exhaust gas into the volume surrounded by the wall of the tubular exhaust guide component. In this case, the upstream side of the wall of such a tubular muffler component forms an outer peripheral surface, while the downstream side provides an inner peripheral surface and is constructed, for example, a flow-through shoulder extending radially inward. It should also be noted that the flow-through opening of such a perforation can be arranged in a pattern different from that shown in the figures, and not all openings of such a perforation need to be the same size. Correspondingly, the flow-through shoulder, for example, arranged in a manner that matches the flow-through openings constructed with different cross-sectional sizes of such a perforation, can also have different extension lengths along the flow direction. For example, compared to a flow-through opening of a smaller defined size, the flow-through shoulder arranged in a manner that matches a flow-through opening of a larger defined size can have a larger extension length.

[0043] In another alternative design approach, the reduced flow cross-section can also be achieved by constructing the flow-through opening guide surface with a substantially truncated conical structure or multiple sections having substantially truncated conical structures successively along the flow direction, thereby achieving a progressive reduction in the flow cross-section of the flow-through opening along the flow direction. However, due to the inevitable formation of vortices in the edge-like transition region, the rounded structure of the flow-through opening guide surface shown in the figure along the flow direction is preferred.

Claims

1. A muffler for an exhaust system of an internal combustion engine, the muffler comprising at least one muffler component (30) having a perforation (42) comprising a plurality of flow openings (44) in a wall (40) of the muffler component (30), wherein, The flow opening (44) is capable of flowing through in the direction of flow (S) from the upstream side (54) of the wall (40) toward the downstream side (58) of the wall (40). At least in a portion of the flow opening (44) of the perforation (42), the flow cross section (D) of the flow opening decreases gradually along the flow direction (S) to provide a flow guide surface (50) for the flow opening. The flow guide surface (50) is characterized in that the angle of inclination of the flow guide surface (50) about the central axis (O) of the opening is in the range of 5° to 15° in the region of the outlet end (46) of the corresponding flow opening (44).

2. The muffler according to claim 1, characterized in that, In all the flow openings (44), the flow cross-section (D) of the flow opening decreases progressively along the flow direction (S).

3. The silencer according to claim 1 or 2, characterized in that, The flow cross section (D) of the flow through the opening decreases in profile with a rounded cross section, or / and the flow cross section of the flow through the opening decreases in profile with a cross section without sharp edges.

4. The silencer according to claim 1 or 2, characterized in that, The flow-through opening guide surface (50) is connected to the upstream side (54) of the wall (40) without any sharp edges.

5. The silencer according to claim 1 or 2, characterized in that, The flow cross-section (D) of the flow opening decreases in the first flow opening-opening length region (L1) corresponding to the wall thickness (W) of the wall (40) between the upstream side (54) and the downstream side (58) of the wall (40).

6. The silencer according to claim 1 or 2, characterized in that, A flow-through shoulder (60) is provided in such a manner as to be matched with at least a portion of the flow-through opening (44), extending downstream via the downstream side (58) of the wall (40) and surrounding the corresponding flow-through opening (44) in a ring shape in the second flow-through opening-opening length region (L2).

7. The muffler according to claim 6, characterized in that, A flow-through shoulder (60) is provided in such a manner as to be matched with all flow-through openings (44), extending downstream via the downstream side (58) of the wall (40) and surrounding the corresponding flow-through opening (44) in a ring shape in the second flow-through opening-opening length region (L2).

8. The muffler according to claim 6, characterized in that, In at least a portion of the flow-through shoulder (60), the flow-through opening cross-section (D) of each flow-through opening (44) surrounded by one of the flow-through shoulders (60) decreases in the second flow-through opening-opening length region (L2).

9. The muffler according to claim 8, characterized in that, In all the flow shoulders (60), the flow opening cross section (D) of each flow opening (44) surrounded by one of the flow shoulders (60) decreases in the second flow opening-opening length region (L2).

10. The muffler according to claim 8, characterized in that, The flow cross section (D) of the through-hole decreases in a first through-hole-opening length region (L1) corresponding to the wall thickness (W) of the wall (40) between the upstream side (54) and the downstream side (58) of the wall (40), and the flow cross section (D) of the through-hole decreases more strongly in the first through-hole-opening length region (L1) than in the second through-hole-opening length region (L2).

11. The silencer according to claim 1 or 2, characterized in that, The at least one muffler component (30) is configured as an exhaust guide pipe (32, 34), or / and the at least one muffler component (30) is configured as a partition wall (22) that separates the two muffler chambers (26, 28) from each other.

12. An exhaust system for an internal combustion engine, said exhaust system comprising at least one muffler (10) according to any one of claims 1 to 11.

13. A method for manufacturing a muffler (10) according to any one of claims 1 to 11, characterized in that, The at least one muffler component (30) is constructed of a metallic material and has a channel formed in the wall (40) of the muffler component (30) for providing the flow-through opening guide surface (50). or The at least one muffler component (30) is constructed as a plastic molded part, and the flow-through opening guide surface (50) is formed onto the wall of the muffler component (30).

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