US20110186379A1

US20110186379A1 - Muffler baffle

Info

Publication number: US20110186379A1
Application number: US12/938,368
Authority: US
Inventors: Gerald L. Rinehart
Original assignee: Rinehart Racing Inc
Current assignee: Rinehart Racing Inc
Priority date: 2010-02-03
Filing date: 2010-11-02
Publication date: 2011-08-04

Abstract

Embodiments of the present invention provide an improved baffle for use in a muffler exhaust system and a system utilizing such baffle. The improved baffle comprises a first conduit portion having a first diameter, a second conduit portion having a second diameter, wherein the second diameter is greater than the first diameter, and a diameter step-up conduit connection portion having two ends, one that connects to the first conduit portion and the other that connects to the second conduit portion. The integrated baffle is disposed within the muffler of an exhaust system such that exhaust from an internal combustion engine enters the first conduit portion first, travels through the first conduit portion and then through the second conduit portion, and is then released into the air. Louvers disposed on the surface area of the first and second conduit portions reduce the noise of the engine while the step-up in diameter from the first conduit portion to the second conduit portion causes a pressure differential between the first conduit portion and the second conduit portion which lessens the back pressure applied on the engine and increases the performance and efficiency of the engine.

Description

FIELD

The invention generally relates to the field of muffler exhaust systems, and more particularly, embodiments of the present invention relate to an improved baffle for use in a muffler exhaust system and a system utilizing such baffle.

BACKGROUND

Muffler exhaust systems are generally used in combination with internal combustion engines to reduce the noise attendant to the operation of such engines. Specifically, muffler exhaust systems often provide one or more channels through which the exhaust gases generated during the combustion process travel prior to being released, which channels are configured to cause interference with, and thus slow down, the noisy exhaust exiting the cylinders of the engine. However, because the channels disrupt the flow of the exhaust gases and cause the gases to exit the exhaust system slower than they would in the absence of any disruption, the pressure within the channels increases and back pressure is exerted on the engine. This back pressure negatively impact performance of the engine. In motorcycles, the muffler baffles utilized in motorcycle exhaust systems to reduce the noise associated with the motorcycle engine can reduce the horsepower of the engine and the efficiency of the motorcycle by causing undesirable back pressure. Thus, there is a need for an improved muffler baffle that not only sufficiently reduces the noise levels of the exhaust gases exiting the engine, but also reduces the back pressure exerted on the engine, thus increasing overall performance and efficiency of the engine.

BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention solve the above-described problem and/or other problems by providing an improved baffle for a muffler exhaust system for an internal combustion engine comprising a first conduit portion having a first diameter connected to a second conduit portion having a second diameter, wherein the second diameter is greater than the first diameter. Numerous louvers are defined in the surface area of both the first conduit portion and the second conduit portion, which louvers penetrate the interior volume of the baffle and disrupting the flow of the exhaust through the muffler-baffle assembly and ultimately reducing the noise of the engine. The open end of the first conduit portion interfaces directly or indirectly with the exhaust being expelled from the combustion engine, while the opposite end of the baffle, which is the open end of the second conduit portion, interfaces with the open air. The baffle is thus configured such that the exhaust from the engine enters the first conduit portion through the open end of the first conduit portion and travels through the first conduit portion and then through the second conduit portion before reaching the open end of the second conduit portion and being released into the air. The step-up in diameter from the first conduit portion to the second conduit portion causes a pressure differential between the first conduit portion and the second conduit portion which advantageously urges the exhaust to travel more quickly through the first conduit to reach the second conduit, which lessens the back pressure applied on the engine and increases the performance and efficiency of the engine.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described embodiments of the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIGS. 1 illustrates the environment in which one embodiment of the baffle of the present invention is used;

FIG. 2 is a perspective view illustrating one embodiment of the baffle of the present invention;

FIG. 3 is a perspective view illustrating a section of the baffle of FIG. 2;

FIG. 4 is a perspective view illustrating a larger section of the baffle of FIG. 2;

FIG. 5 is a cross-sectional view along line 5-5 of FIG. 4 illustrating the interior surface of the baffle, in accordance with one embodiment of the present invention;

FIG. 6( a) is a cross-sectional view of a third slip joint between the female extension of the muffler slidably receiving a male extension from a first end of the header pipe extending from a combustion engine;

FIG. 6( b) is a cross-sectional view of a first slip joint formed by the exhaust inlet end of the baffle slidably receiving a male extension from a first end of the muffler; and

FIG. 6( c) is a cross-sectional view of a second slip joint formed by the exhaust outlet end of the baffle slidably engaging a groove in an end cap that is slidably received about the second end of the muffler.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Referring to FIGS. 1 and 2, there is illustrated a baffle 10 in accordance with one embodiment of the present invention disposed within the interior passage defined by the muffler 30 of a motorized vehicle that is connected to the header pipe extending from the combustion engine of the vehicle. The motorized vehicle may include a motorcycle, car, race car, truck, airplane, water craft, etc. having a combustion engine. The baffle 10 is mounted within the muffler 30, preferably in a concentric arrangement. In one embodiment, as illustrated in FIGS. 6( b) and 6(c), the baffle 10 is mounted within the muffler 30 via first and second mating slip- joints 32 and 34. As illustrated in FIG. 6( b), the first slip joint 32 is formed by the exhaust inlet end 18 of the baffle 10 slidably receiving a male extension 31 from a first end 30 a of the muffler 30. In one embodiment, the length of the male extension 31 extending from the first end 30 a of the muffler 30 is approximately four (4) inches. In the embodiment illustrated in FIG. 6( b), the muffler 30 is tapered approximate the first slip joint 32. Although the muffler 30 design illustrated in FIG. 6( b) is a different muffler design than the “two-into-one” design illustrated in FIG. 1, which has a more gradual taper along the length of the muffler 30, the first slip joint 32 used to connect the exhaust inlet end 18 of the baffle 10 to the male extension 31 from the first end 30 a of the muffler 30 in both designs is preferably the same.
As illustrated in FIG. 6( c), which is a different muffler design than the “two-into-one” design illustrated in FIG. 1, the second slip joint 34 is formed by the second end 30 b of the muffler 30 being slidably received within a groove defined by an end cap 36. The end cap 36 defines a recess machined or otherwise formed within the inside diameter of the end cap that is configured to receive the edge of the exhaust outlet end 20 of the baffle 10 so as to retain the baffle within the muffler 30. The end cap 36 may be secured to the second end 30 b of the muffler 30 via one or more set screws 38, or alternatively, using an adhesive, welding or the like. In the design illustrated in FIG. 1, the econd end 30 b of the muffler 30 is not structured to receive an end cap, so the exhaust outlet end 20 of the baffle 10 can be mounted within the muffler using metallic protrusions 39 as support and then secured with mechanical fasteners such as screws or by welding or other means.
As illustrated in FIG. 6( a), a third slip joint 33 is formed by a female extension 35 extending from a first end 30 a of the muffler 30 slidably receiving a male extension 40 from a first end 40 a of a header pipe 42 extending from a combustion engine (not shown). In one embodiment, the length of the female extension 35 extending from the first end 30 a of the muffler 30 is approximately four (4) inches. For a dual header pipe design, such as the one illustrated in FIG. 1, each pipe will have a corresponding third slip joint 33. The design, specification, and configuration of the muffler 30, header pipe(s) 42 and combustion engine may vary depending on the specifications of the motorized vehicle as will be understood by one of ordinary skill in the art.
The baffle 10 comprises a first conduit portion 12 and a second conduit portion 14 disposed along the same longitudinal axis with a step-up conduit connector 16 disposed between the first conduit portion 12 and the second conduit portion 14 and connected to the first conduit portion 12 on one end and connected to the second conduit portion 14 on the opposite end. In one embodiment, the cross-sectional area of the second conduit portion 14 is greater than the cross-sectional area of the first conduit portion 12. In other embodiment, the cross-sectional area of the second conduit portion 14 is less than the cross-sectional area of the first conduit portion 12. According to some embodiments, and as illustrated in FIG. 2, the first conduit portion 12 and the second conduit portion 14 both have a tubular configuration and the diameter of the second conduit portion 14 is greater than the diameter of the first conduit portion 12. In some embodiments, the diameter of the second conduit portion 14 is less than the diameter of the first conduit portion 12. In some embodiments, the second conduit portion 14 is longer than the first conduit portion 12. In some embodiments, the second conduit portion 14 is shorter than the first conduit portion 12. The baffle 10 further comprises an exhaust inlet opening 18 disposed on the end of the first conduit portion 12 opposite the end of the first conduit portion 12 that is connected to the step-up conduit connector 16 and an exhaust outlet opening 20 disposed on the end of the second conduit portion 14 opposite the end of the second conduit portion 14 that is connected to the step-up conduit connector 16. In some embodiments, the exhaust inlet opening 18 is flared, as illustrated in FIG. 2. In some embodiments, the exhaust outlet opening 20 is flared. Additionally, the baffle 10 may comprises a plurality of louvers 22 that are disposed on the surface of the first conduit portion 12 and/or the second conduit portion 14, either randomly or in a pre-determined pattern.
According to some embodiments, the step-up conduit connector 16 comprises a portion of a conduit having non-uniform cross-sectional area. In particular, with reference now to FIGS. 3 and 4, the step-up conduit connector 16 comprises a portion of a conduit having a cross-sectional area and configuration that is the same as the cross-sectional area and configuration of the first conduit portion 12 at the end of the step-up conduit connector 16 connecting to the first conduit portion 12, and then increases in size along its longitudinal axis to the opposite end of the step-up conduit connector 16 where it connects to the second conduit portion 14 and has a cross-sectional area and configuration the same as the cross-sectional area and configuration of the second conduit portion 12. For example, in the case of tubular first and second conduit portions 12 and 14, the step-up conduit portion has a diameter the same as the diameter of the first conduit portion 12 at its end connecting to the first conduit portion 12, then increases in diameter until the diameter is the same as the diameter of the second conduit portion 14, at which point it connects to the second conduit portion 14. According to different embodiments, the increase in size of the cross-sectional area of the baffle 10 that is provided by the step-up conduit connector 16 may be accomplished gradually throughout the length of the step-up conduit connector 16 or abruptly, for example, through a substantial increase in diameter at a particular cross-sectional plane of the step-up connector 16.
Thus, the first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 are connected to form an integrated baffle 10 having a uniform cross-sectional area throughout the first conduit portion 12, a step-up in size of cross-sectional area in the step-up conduit connector, and a uniform cross-sectional area throughout the second conduit portion 14 that is greater than the cross-sectional area of the first conduit portion 12. The first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may be formed integrally with one another such that the baffle 10 comprises a single integral piece or they may be formed as separate pieces and attached via mechanical fasteners, welding or other means, such as being screwed together via matching threads or by pressure fitting the ends together. Furthermore, each of the first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may not be an integral piece and may be comprised of two or more separate pieces attached via mechanical fasteners, welding or other means, including by screwing the corresponding ends together via matching threads or by pressure fitting the ends together. In particular, according to some embodiments, the step-up conduit connector 16 is not a single integral piece. For example, in one embodiment, the step-up conduit connector 16 comprises a conduit formed integrally with the first conduit portion 12 and a conduit formed integrally with the second conduit portion 14, wherein the two conduits of the step-up conduit connector 16 are welded together or attached via mechanical fasteners or other means, such as being screwed together via matching threads or by pressure fitting the ends together. It should be appreciated that there are countless methods of manufacture available to one having skill in the art that may be employed to construct the baffle 10 of the present invention.
The first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may be formed using similar or dissimilar metals and metal alloys. In one embodiment, the first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may be formed 1010 mild steel. In another embodiment, the first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may be formed of an aluminized 1010 mild steel, which will resist rusting than the 1010 mild steel. In yet another embodiment, the first conduit portion 12, second conduit portion 14, and step-up conduit connector 16 may be formed of 304-L stainless steel. Such materials are preferable as they are suited to withstand the high temperatures of the exhaust gases with the 304-L stainless steel being preferred for applications with higher temperatures. However, any other material known in the art may be utilized.
In some embodiments, the cross-sectional area of the second conduit portion 14 is larger than the cross-sectional area of the first conduit portion 12 by a ratio falling within the range of 2.25 inches (outside diameter) to 2 inches (outside diameter), 2.5 inches (outside diameter) to 2 inches (outside diameter), 2.5 inches (outside diameter) to 2.25 inches (outside diameter). In other embodiments, depending on the application, the range could be 3 inches (outside diameter) to 2.75 inches (outside diameter), 3.25 inches (outside diameter) to 3 inches (outside diameter), or even a 3.5 inches (outside diameter) to 3.25 inches (outside diameter). In most embodiments, the range will differ by approximately 0.25 inches (outside diameter) to 0.5 inches (outside diameter), or even up to 0.75 inches (outside diameter) or 1 inch (outside diameter). In some embodiments, the length of the second conduit portion 14 and the length of the first conduit portion 12 are the same and in some embodiments the length of the second conduit portion 14 is longer that the length of the first conduit portion 12 by a length up to approximately 6 inches. The longer the length of the second conduit portion 14 relative to the length of the first conduit portion 12, then the greater the increase in engine torque and greater the decrease in top-end horse power, whereas as the length of the first conduit portion 12 and second conduit portion 14 approach one another, then there is an increase in top-end horse power and a decrease in engine torque. In other embodiments, the length of the first conduit portion 12 is longer than the length of the second conduit portion 14.
The thickness of the material may vary according to the material used. According to one embodiment, the baffle 10, including the first conduit portion 12, second conduit portion 14, and diameter step-up connector 16 comprise a thickness of 0.049 inches if using 304-L stainless steel or 0.065 inches if using 1010 mild steel or aluminized 1010 mild steel. Other thicknesses are also possible, for example a thickness of 0.035 inches if the material is a 321 stainless steel or a titanium, Inconel® (which is a registered trademark of Special Metals Corporation) or material of similar strength. It should be noted that while the baffle 10 is illustrated as comprising tubular conduit portions having circular cross-sections, other cross-sectional geometric shapes are within the scope of the present invention.
Referring again to FIG. 2, louvers 22 are defined in the surface area of both the first conduit portion 12 and the second conduit portion 14. Referring now to FIG. 5, each louver 22 comprises an aperture 26 through the baffle 10, whether through the first conduit portion 12, the second conduit portion 14, or even the step-up conduit connector 16, and a lip 28 that extends into the interior volume of the baffle 10. The apertures 26 and lips 28 of the louvers 22 serve to disrupt the flow of gas through the baffle 10, causing what would otherwise be laminar flow to become turbulent. Thus, the velocity of the exhaust exiting the engine is reduced as the exhaust travels through the baffle 10 and is subjected to the interference caused by the louvers 22. This advantageously can reduce the noise associated with the exhaust. In one embodiment, each louver 22 is comprised of an aperture 26 approximately ⅜ inch in width and a lip that penetrates the interior volume of the baffle 10 by approximately ¼ inch in depth. According to some embodiments, and as illustrated in FIG. 2, the louvers 22 may be disposed on the surface area of the first conduit portion 12 and the second conduit portion 14 in a spiral pattern down at least a portion of the length of the first conduit portion 12 and the second conduit portion 14, which can facilitate the drawing effect discussed below. However, it should be appreciated that other configurations of louvers 22, including the size and shape of each louver or the disposition of the louvers 22 on the surface area of the baffle 10, that are known by those having skill in the art are within the scope of the present invention.
Referring again to FIGS. 1 and 2, according to some embodiments of the present invention, the first conduit portion 12 is configured to receive through the inlet opening 18 exhaust gases created by an internal combustion engine. Thus, the baffle 10 is disposed within the muffler 20 such that inlet opening 18 interfaces directly or indirectly with the exhaust output of the engine. The exhaust enters through the inlet opening 18, travels through the first conduit portion 12, then through the diameter step-up connector 16, then through the second conduit portion 14, before finally exiting the baffle 10 through the outlet opening 20. It is an object of the present invention that the increase in the cross-sectional area of the baffle 10 from the first conduit portion 12 to the second conduit portion 14 via the step-up connector 16 causes a pressure differential between the first conduit portion 12 and the second conduit portion 14, wherein the pressure inside the second conduit portion 14 is lower than the pressure inside the first conduit portion 12. The pressure differential causes the exhaust to be drawn from the first conduit portion 12 into the second conduit portion 14, causing the exhaust to travel more quickly through the first conduit portion 12 than it would if the baffle 10 were uniform in cross-sectional area, thus reduces the pressure in the first conduit portion 12 and, consequently, the performance-reducing back pressure on the engine.
Specific embodiments of the invention are described herein. Many modifications and other embodiments of the invention set forth herein will come to mind to one skilled in the art to which the invention pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments and combinations of embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A baffle for use in the exhaust system of a combustion engine, comprising:

a first conduit portion having a first cross-sectional area and comprising an exhaust inlet end configured to receive exhaust from the combustion engine and a first connecting end opposite the exhaust inlet end;

a second conduit portion having a second cross-sectional area and comprising an exhaust outlet end and a second connecting end opposite the exhaust outlet end, wherein the second cross-sectional area is different than the first cross-sectional area; and

a step-up conduit connection portion disposed between the first conduit portion and the second conduit portion comprising a first end having the first cross-sectional area and a second end having the second cross-sectional area, wherein the first end of the step-up conduit connection portion is connected to the first connecting end of the first conduit portion and the second end of the step-up conduit connection portion is connected to the second connecting end of the second conduit portion.

2. A baffle according to claim 1 wherein the first conduit portion and the second conduit portion are formed of the same material.

3. A baffle according to claim 1 wherein the first conduit portion and the second conduit portion are formed of the same material.

4. A baffle according to claim 1 wherein the baffle comprises at least one material selected from the group comprising 1010 mild steel, aluminized 1010 mild steel and 304-L stainless steel.

5. A baffle according to claim 1 wherein the first cross-sectional area is greater than the second cross-sectional area.

6. A baffle according to claim 1 wherein the first cross-sectional area is greater than the second cross-sectional area.

7. A baffle according to claim 1 wherein at least one of the first conduit portion and the second conduit portion comprises a plurality of louvers.

8. A baffle according to claim 1 wherein the first conduit portion and the second conduit portion have different lengths.

9. A baffle according to claim 10 wherein the length of the first conduit portion is less than the length of the second conduit portion.

10. An apparatus for a motorized vehicle powered by a combustion engine, comprising:

a muffler defining a first end and a second end and an interior passage between the first end and the second end;

a baffle secured within the interior passage of the muffler, the baffle comprising:

a first conduit portion having a first cross-sectional area and comprising an exhaust inlet end configured to receive exhaust from the combustion engine and a first connecting end opposite the exhaust inlet end, the exhaust inlet end being positioned adjacent to the first end of the muffler;

a second conduit portion having a second cross-sectional area and comprising an exhaust outlet end and a second connecting end opposite the exhaust outlet end, the exhaust outlet end being positioned adjacent the second end of the muffler, wherein the second cross-sectional area is different than the first cross-sectional area; and

11. An apparatus according to claim 10 wherein the first conduit portion and the second conduit portion are formed of the same material.

12. An apparatus according to claim 10 wherein the first conduit portion and the second conduit portion are formed of the same material.

13. An apparatus according to claim 10 wherein the baffle comprises at least one material selected from the group comprising 1010 mild steel, aluminized 1010 mild steel and 304-L stainless steel.

14. An apparatus according to claim 10 wherein the first cross-sectional area is greater than the second cross-sectional area.

15. An apparatus according to claim 10 wherein the first cross-sectional area is greater than the second cross-sectional area.

16. An apparatus according to claim 10 wherein the first cross-sectional area is less than the second cross-sectional area.

17. An apparatus according to claim 16 wherein the first cross-sectional area is less than the second cross-sectional area by up to approximately one (1) inch.

18. An apparatus according to claim 10 wherein at least one of the first conduit portion and the second conduit portion comprises a plurality of louvers.

19. An apparatus according to claim 10 wherein the first conduit portion and the second conduit portion have different lengths.

20. An apparatus according to claim 19 wherein the length of the first conduit portion is less than the length of the second conduit portion.

21. An apparatus according to claim 10 wherein the first conduit portion, the second conduit portion and the step-up conduit connection portion are formed integrally together.