Exhaust mufflers for internal combustion engines

Abstract

Various implementations include a muffler having a shell and a tube assembly. The shell defines a shell cavity and has a shell longitudinal axis, a shell first end, and a shell second end, each of which defines a shell opening extending into the shell cavity. The tube assembly is disposed within the shell cavity. The tube assembly includes three or more nested tubes. Each of the three or more nested tubes has a tube longitudinal axis parallel to the shell longitudinal axis, a tube first end, and a tube second end. Each of the three or more nested tubes defines a plurality of perforations. The three or more nested tubes are disposed circumferentially adjacent to one another around the shell longitudinal axis such that portions of the sides of the three or more nested tubes form openings extending along the shell longitudinal axis.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates to the field of attenuating the sound of exhaust streams from internal combustion engines. More particularly, this disclosure relates to mufflers for use with internal combustion engines and the like. [Background technology]

[0002] The problem of mufflers and noise reduction devices used to silence the noise generated or emitted as exhaust gases from internal combustion engines is well known. Many different types of mufflers and noise reduction devices have been developed to address these issues. One type of muffler, commonly referred to as an absorption muffler, consists of a uniform, end-to-end perforated tube with a sound-absorbing material, such as fiberglass, between the tube and an outer housing to direct the gases. These mufflers typically provide low back pressure, but are not very effective at reducing the noise level emitted by the muffler.

[0003] Another type of muffler is the resonator muffler. Resonator mufflers typically use a series of baffle plates to reroute exhaust gases. By blocking or redirecting the gas flow, sound frequencies passing through them are reflected by the baffle plates back toward the noise source, mechanically canceling out at the point of impact. This type of muffler can provide some noise reduction; however, the partial blockage of the exhaust flow can increase exhaust backpressure.

[0004] Other examples of mufflers include those described in U.S. Patent Nos. 5,198,625 and 8,439,159. These mufflers can provide reduced backpressure and reduced noise levels. However, in high performance applications, such as racing applications, further reduction in backpressure and noise levels may be desirable.

[0005] Therefore, there is a need for a muffler that further reduces exhaust system noise levels and backpressure, can be used for extended periods in auto racing, and is packaged for mounting underneath racing and high performance automobiles. Summary of the Invention

[0006] Some embodiments described herein relate to a muffler. The muffler includes a shell and a tube assembly disposed within the shell. The tube assembly includes a first collar having an opening at a first end and a plurality of lobes at a second end, a second collar having a plurality of lobes at the first end and an opening at the second end, and a plurality of nested tubes between the plurality of lobes of the first collar and the plurality of lobes of the second collar. The plurality of nested tubes are perforated. The opening is disposed at a center of the tube assembly. The opening has a shape defined by the sidewalls of the plurality of nested tubes. The opening is aligned with the center of the tube assembly.

[0007] Various implementations include a muffler. The muffler includes a shell and a tube assembly. The shell defines a shell cavity. The shell has a shell longitudinal axis, a shell first end, and a shell second end spaced apart from the shell first end along the shell longitudinal axis, each of the shell first end and the shell second end defining a shell opening extending into the shell cavity. A tube assembly is disposed within the shell cavity. The tube assembly includes three or more nested tubes. Each of the three or more nested tubes has a tube longitudinal axis parallel to the shell longitudinal axis, a tube first end, and a tube second end spaced apart from the tube first end along the tube longitudinal axis, each of the three or more nested tubes defining a plurality of perforations. The three or more nested tubes are disposed circumferentially adjacent to one another around the shell longitudinal axis such that side portions of the three or more nested tubes form openings extending along the shell longitudinal axis.

[0008] In some implementations, the tube assembly further includes a first collar and a second collar, each defining a collar longitudinal axis, a collar first end, and a collar second end spaced apart from the collar first end along the collar longitudinal axis. In some implementations, the collar first end defines a collar opening extending to the collar second end. In some implementations, the tube first end of each of the three or more nested tubes is disposed within the collar second end of the first collar, and the tube second end of each of the three or more nested tubes is disposed within the collar second end of the second collar.

[0009] In some implementations, the collar opening at the collar first end has a first cross-sectional area when viewed from a plane perpendicular to the collar longitudinal axis, and the collar opening at the collar second end has a second cross-sectional area when viewed from a plane perpendicular to the collar longitudinal axis, and the second cross-sectional area is greater than the first cross-sectional area.

[0010] In some implementations, the collar first end is cylindrical.

[0011] In some implementations, the collar opening at the collar second end of the first collar and the second collar define three or more lobes having an arcuate cross-section when viewed perpendicular to the collar longitudinal axis. In some implementations, each of the three or more nested tubes is disposed within a different one of the three or more lobes. In some implementations, each of the three or more lobes has a radius of curvature corresponding to the radius of curvature of one of the three or more nested tubes.

[0012] In some implementations, the muffler further includes a first end cap and a second end cap. In some implementations, the first end cap and the second end cap each define an end cap opening, and the first end cap is disposed within the shell opening at the first end of the shell. In some implementations, the second end cap is disposed within the shell opening at the second end of the shell. In some implementations, the first collar end of the first collar is disposed within the end cap opening of the first end cap, and the first collar end of the second collar is disposed within the end cap opening of the second end cap.

[0013] In some implementations, the end cap opening defines a flange extending axially relative to the shell longitudinal axis, hi some implementations, the flange of the end cap opening is configured to be connectable to either an intake duct or an exhaust duct of an exhaust system.

[0014] In some implementations, the three or more nested tubes comprise five or more nested tubes, hi some implementations, the five or more nested tubes comprise six or more nested tubes.

[0015] In some implementations, each of the three or more nested tubes has an exterior surface. In some implementations, the plurality of perforations are disposed in a portion of the exterior surface that covers 5% to 80% of each of the three or more nested tubes. In some implementations, the portion of the exterior surface covers 20% to 40% of each of the three or more nested tubes. In some implementations, the plurality of perforations are disposed in a portion of the exterior surface that covers 100% of each of the three or more nested tubes.

[0016] In some implementations, the shell has an elliptical cross-sectional shape when viewed from a plane perpendicular to the longitudinal axis of the shell.

[0017] In some implementations, the muffler further includes a sound absorbing material disposed within the shell cavity between the three or more nested tubes and the shell. In some implementations, the sound absorbing material includes steel wool. In some implementations, the sound absorbing material includes glass fiber. In some implementations, the sound absorbing material includes ceramic fiber. [Brief explanation of the drawings]

[0018] Exemplary features and embodiments of the present disclosure are disclosed in the accompanying drawings, but the present disclosure is not limited to the precise arrangements and devices shown in the drawings. Similar elements in different embodiments are designated with the same reference numerals. [Figure 1] FIG. 1 shows a perspective view of a muffler according to one embodiment of the present disclosure. [Figure 2] FIG. 2 shows a cross-sectional side view of a muffler according to one embodiment of the present disclosure. [Figure 3] FIG. 3 shows an end view of a muffler according to one embodiment of the present disclosure. [Figure 4] FIG. 4 shows a perspective view of a tube assembly of a muffler according to one embodiment of the present disclosure. [Figure 5] FIG. 5 shows an end view of a tube assembly of a muffler according to one embodiment of the present disclosure. [Figure 6A] FIG. 6A shows a perspective view of a collar of a tube assembly according to one embodiment of the present disclosure. [Figure 6B] FIG. 6B shows an end view of a collar of a tube assembly according to one embodiment of the present disclosure. [Figure 7] FIG. 7 illustrates an exhaust system including a muffler according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] Various terms used herein are intended to have specific meanings. Some of these terms are defined below for clarity. The definitions set forth below are intended to include all forms (e.g., singular, plural, present tense, past tense) of the defined word. In the event that a definition set forth below differs from a commonly understood or dictionary definition of such term, the definition set forth below shall control.

[0020] 1 illustrates an embodiment of a muffler 10 adapted for use with an internal combustion engine. The muffler 10 is configured to attenuate, modify, or reduce the sound of the internal combustion engine generated by high velocity air or gases flowing through the muffler 10. The muffler 10 is suitable for installation on vehicles such as high performance automobiles and racing automobiles.

[0021] Muffler 10 includes a shell 12 defining a shell cavity 13. Shell 12 has a shell longitudinal axis 15, a shell first end 52, and a shell second end 54 spaced apart from shell first end 52 along shell longitudinal axis 15. Shell first end 52 and shell second end 54 each define a shell opening 56 that extends into shell cavity 13. Shell 12 is cylindrically formed and may have a cross-section such that shell 12 forms an elliptical or oval cylinder, as shown in FIG. 1 . Shell 12 may be formed from a sheet of material, such as stainless steel, and joined with a seam weld 14.

[0022] As shown in FIG. 2, first and second end caps 16 and 18 are disposed on opposite ends of the shell 12 of the muffler 10. The first and second end caps 16 and 18 may be telescopically secured within shell openings 56 in the first and second shell ends 52 and 54, respectively. The first and second end caps 16 and 18 may include end cap openings 21 (FIG. 4) defining flanges 20 extending axially relative to the shell longitudinal axis 15. The flanges 20 of the end cap openings 21 are configured to be connectable to either an inlet duct 22 or an outlet duct 24 (FIG. 7). The inlet duct 22 and the outlet duct 24 are configured to be received on or within the flanged openings 20 of the first and second end caps 16 and 18, respectively. For example, one or both of the inlet duct 22 and the outlet duct 24 may be received in the flanged openings 20 in the first end cap 16 and the second end cap 18 by band clamps 26 .

[0023] 4, tube assembly 28 is disposed within shell cavity 13 of shell 12 of muffler 10. Tube assembly 28 has first and second collars 30 and 32, each defining a collar longitudinal axis 31, a collar first end 58, and a collar second end 60 oppositely spaced from collar first end 58 along collar longitudinal axis 31. Collar first end 58 defines a collar opening 38 that extends to collar second end 60.

[0024] The tube assembly 28 further includes a plurality of nested tubes 34. Each of the nested tubes 34 has a tube longitudinal axis 35 parallel to the shell longitudinal axis 15, a tube first end 62, and a tube second end 64 oppositely spaced from the tube first end 62 along the tube longitudinal axis 35. The tube first end 62 of each of the nested tubes 34 is disposed within the collar second end 60 of the first collar 30, and the tube second end 64 of each of the nested tubes 34 is disposed within the collar second end 60 of the second collar 32.

[0025] The first collar 30 and the second collar 32 may be frustoconical such that the cross-sectional area of ​​the collar opening 38 at the collar second end 60, when viewed in a plane perpendicular to the collar longitudinal axis 31, is greater than the cross-sectional area of ​​the collar opening 38 at the collar first end 58, when viewed in a plane perpendicular to the collar longitudinal axis 31. The collar second end 60 of each of the first collar 30 and the second collar 32 is configured to receive a nested tube 34 configured in a substantially circular shape around the first collar 30 and the second collar 32. The first collar 30 and the second collar 32 may support the nested tube 34 in a circular arrangement, as shown in FIG. 5 . Thus, the nested tubes 34 are circumferentially adjacently disposed around the shell longitudinal axis 15 such that a portion of the side of the nested tube 34 forms an opening 42 extending along the shell longitudinal axis 15.

[0026] 6A and 6B illustrate a first collar 30 in which the second collar 32 and the first collar 30 are identical or substantially identical. The collar second end 60 of the first collar 30 and the second collar 32 can have a plurality of lobes 36, each having an arcuate cross-section when viewed perpendicular to the collar longitudinal axis 31. Each of the lobes 36 has a radius of curvature corresponding to the radius of curvature of one of the nested tubes 34. Each of the nested tubes 34 is disposed within a different one of the lobes 36 to support opposing ends of the nested tubes 34. The nested tubes 34 may be supported in lateral contact with each other along the length of the nested tubes 34. As shown in the figures, the first collar 30 and the second collar 32 can have six lobes 36 corresponding to six of the nested tubes 34 held in the first collar 30 and the second collar 32.

[0027] The collar first ends 58 of the first collar 30 and the second collar 32 may include cylindrical shapes sized such that the collar first ends of the first collar are positioned within the end cap openings of the first end cap and the first collar ends of the second collar are positioned within the end cap openings of the second end cap.

[0028] 1-7 includes six nested tubes 34, in some implementations the tube assembly includes any number of nested tubes greater than or equal to three, with each of the first and second collars defining the same number of lobes, or greater than or equal to three. In some implementations, the tube assembly includes five nested tubes, with each of the first and second collars defining five lobes.

[0029] 5 , the nested tubes 34 are positioned on the first collar 30 and the second collar 32 such that the nested tubes 34 are arranged in a circular configuration around an opening 42 at the center of the tube assembly 28. The opening 42 has a cross-sectional area corresponding to the space defined between the inner sides of the nested tubes 34 of the tube assembly 28. The openings 42 may extend along the length of the tube assembly 28 between the nested tubes 34 and be substantially aligned with the collar longitudinal axis 31. The openings 42 may form a central channel or conduit along the length of the tube assembly 28 to allow the flow of exhaust gases through the center of the tube assembly 28.

[0030] 4, the nested tube 34 includes a plurality of perforations 40 formed around the periphery of the nested tube 34. The perforations 40 may be formed around the periphery of the nested tube 34 along the length of the nested tube 34. The perforations 40 may be disposed substantially completely around the periphery of the nested tube 34 along the length of the nested tube 34 between the first collar 30 and the second collar 32 of the tube assembly 28.

[0031] In one embodiment, the total area covered by the perforations 40 can range from about 5.0% to about 80% of the total surface area of ​​each of the nested tubes 34. The total area covered by the perforations 40 can range from about 20% to about 40% of the total surface area of ​​the nested tubes 34. The range of surface area of ​​the nested tubes 34 covered by the perforations 40 can allow for varying amounts of gas interconnection from the openings 42 to the nested tubes 34, between the nested tubes 34, and from the nested tubes 34 to the interior volume of the muffler 10. In some implementations, the total area covered by the perforations 40 can be 100%.

[0032] 2, the space within shell cavity 13 between shell 12 and nested tubes 34 of muffler 10 may be filled with sound-absorbing material 44. For example, sound-absorbing material 44 may include one or more of steel wool, fiberglass, and ceramic fiber. In some embodiments, the space between shell 12 and nested tubes 34 of muffler 10 may be hollow or may be devoid of sound-absorbing material 44.

[0033] 7, the muffler 10 may be part of an exhaust system 46 that may be used, for example, in a vehicle featuring an internal combustion engine. The exhaust system 46 may include a pair of mufflers 10 for receiving exhaust gases from banks of cylinders of the internal combustion engine. Each of the mufflers 10 may be positioned downstream of an upstream muffler 48 such that the exhaust gases first pass through the upstream muffler 48 before reaching the muffler 10. Exhaust gases from the exhaust system 46 may exit through a pair of exhaust tips 50. The exhaust tips 50 may be oriented to discharge exhaust gases from the exhaust system 46 out the sides of the vehicle.

[0034] During operation, exhaust gases flow from the inlet duct 22 into the first collar 30, where they diffuse or expand to reduce the temperature of the exhaust gases and change the acoustic frequency of sound waves within the first collar 30. A portion of the exhaust gases then flows into the nested tubes 34, where the exhaust gases and acoustic pulses travel through the perforations 40 in the nested tubes 34, attenuating the exhaust sound waves. If the muffler 10 includes sound-absorbing material 44 within the shell 12 of the muffler 10, some of the exhaust sound waves may travel through the perforations 40 and into the sound-absorbing material 44. At least some of the exhaust sound waves may cancel each other out to attenuate the sound of an exhaust system including the muffler 10. Other portions of the exhaust gases and sound waves may travel through the central opening 42 of the tube assembly 28, allowing some of the exhaust gases to travel through the tube assembly 28 substantially unimpeded by the nested tubes 34. The various exhaust gases and sound waves then enter a second collar 32 where the sound waves and exhaust gases may be recombined into a single flow through the outlet duct 24 .

[0035] The configuration of the muffler 10 advantageously increases the surface area through which the exhaust gases flow, allowing frequencies in the exhaust to cancel each other. Additionally, the centrally located opening 42 of the muffler 10 allows a portion of the exhaust gases to effectively flow through the muffler 10, reducing backpressure and improving performance of the internal combustion engine.

[0036] Numerous exemplary implementations are provided herein. However, it will be understood that various modifications can be made without departing from the spirit and scope of the disclosure herein. As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, the term "comprising" and variations thereof are used synonymously with the term "including" and variations thereof and are open, non-limiting terms. Although the terms "comprising" and "having" have been used herein to describe various implementations, the terms "consisting essentially of" and "consisting of" can be used in place of "comprising" and "having" to provide more specific implementations and are disclosed.

[0037] Disclosed are materials, systems, devices, methods, compositions, and components that can be used for, can be used in combination with, can be used in preparation for, or are products of the disclosed methods, systems, and devices. While these and other components are disclosed herein, when combinations, subsets, interactions, groups, etc. of these components are disclosed, it is understood that the particular components are disclosed, but not the specific components. When combinations, subsets, interactions, groups, etc. of these components are disclosed, it is understood that specific reference to the various individual and collective combinations and permutations of these components may not be explicitly disclosed, but each is specifically contemplated and described herein. For example, when a device is disclosed and discussed, each combination and permutation of that device is disclosed herein, and unless specifically indicated to the contrary, possible variations are specifically contemplated. Likewise, any subset or combination of these is also specifically contemplated and disclosed. This concept applies to all aspects of the present disclosure, including, but not limited to, steps in methods using the disclosed systems or devices. Thus, if there are various additional steps that can be performed, it is understood that each of these additional steps can be performed with any particular method step or combination of method steps of the disclosed methods, and that each such combination or subset of combinations is to be considered specifically contemplated and disclosed.

Claims

1. a shell defining a shell cavity, the shell having a shell longitudinal axis, a shell first end, and a shell second end spaced apart from the shell first end along the shell longitudinal axis, the shell first end and the shell second end each defining a shell opening extending into the shell cavity; a tube assembly disposed within the shell cavity and including three or more nested tubes, each of the three or more nested tubes having a tube longitudinal axis parallel to the shell longitudinal axis, a tube first end, and a tube second end spaced opposite from the tube first end along the tube longitudinal axis, each of the three or more nested tubes defining a plurality of perforations; the three or more nested tubes are arranged circumferentially adjacent one another about the shell longitudinal axis such that side portions of the three or more nested tubes form openings extending along the shell longitudinal axis.

2. 2. The muffler of claim 1, wherein the tube assembly further includes a first collar and a second collar each defining a collar longitudinal axis, a collar first end, and a collar second end oppositely spaced from the collar first end along the collar longitudinal axis, the collar first end defining a collar opening extending to the collar second end, the tube first end of each of the three or more nested tubes being disposed within the collar second end of the first collar, and the tube second end of each of the three or more nested tubes being disposed within the collar second end of the second collar.

3. 3. The muffler of claim 2, wherein the collar opening at the collar first end has a first cross-sectional area when viewed from a plane perpendicular to the collar longitudinal axis, and the collar opening at the collar second end has a second cross-sectional area when viewed from a plane perpendicular to the collar longitudinal axis, the second cross-sectional area being greater than the first cross-sectional area.

4. The muffler of claim 2 , wherein the collar first end is cylindrical.

5. 3. The muffler of claim 2, wherein the collar openings at the collar second ends of the first and second collars define three or more lobes having arcuate cross sections when viewed perpendicular to the collar longitudinal axis, and wherein each of the three or more nested tubes is disposed within a different one of the three or more lobes.

6. 6. The muffler of claim 5, wherein each of the three or more lobes has a radius of curvature that corresponds to a radius of curvature of one of the three or more nested tubes.

7. 3. The muffler of claim 2, further comprising a first end cap and a second end cap, each of the first end cap and the second end cap defining an end cap opening, the first end cap being disposed within the shell opening at the shell first end and the second end cap being disposed within the shell opening at the shell second end.

8. 8. The muffler of claim 7, wherein the collar first end of the first collar is disposed within the end cap opening of the first end cap and the first collar end of the second collar is disposed within the end cap opening of the second end cap.

9. The muffler of claim 7 , wherein the end cap opening defines a flange extending axially relative to the shell longitudinal axis.

10. 10. The muffler of claim 9, wherein the flange of the end cap opening is configured for connection to either an intake duct or an exhaust duct of an exhaust system.

11. The muffler of claim 1 , wherein the three or more nested tubes comprise five or more nested tubes.

12. The muffler of claim 11 , wherein the five or more nested tubes comprise six or more nested tubes.

13. 2. The muffler of claim 1, wherein each of the three or more nested tubes has an exterior surface, and the plurality of perforations are disposed in a portion of the exterior surface covering between 5% and 80% of each of the three or more nested tubes.

14. 14. The muffler of claim 13, wherein the portion of the exterior surface covers between 20% and 40% of each of the three or more nested tubes.

15. 2. The muffler of claim 1, wherein each of the three or more nested tubes has an exterior surface, and the plurality of perforations are disposed in a portion of the exterior surface that provides 100% coverage of each of the three or more nested tubes.

16. The muffler of claim 1 , wherein the shell has an elliptical cross-sectional shape when viewed from a plane perpendicular to the shell longitudinal axis.

17. The muffler of claim 1 , further comprising a sound absorbing material disposed within the shell cavity between the three or more nested tubes and the shell.

18. 18. The muffler of claim 17, wherein the sound absorbing material comprises steel wool.

19. 18. The muffler of claim 17, wherein the sound absorbing material comprises fiberglass.

20. 18. The muffler of claim 17, wherein the sound absorbing material comprises ceramic fibers.

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