DESC:FIELD OF THE INVENTION

This invention relates to an exhaust muffler of an internal combustion engine. The invention relates, more particularly, though not exclusively, to internal design of an exhaust muffler of an internal combustion engine.

BACKGROUND OF THE INVENTION

Internal combustion engines are generally equipped with an exhaust muffler in order to achieve desired performance characteristics (for example emission of the engine, reduce noise of combustion from of the engine and to allow burnt/combust products of combustion of air-fuel mixture to escape to the atmosphere in a defined direction. The modern age exhaust mufflers are equipped with CAT or catalytic converter to reduce the harmful contents in the exhaust gas which is escape in the atmosphere through the exhaust muffler. The exhaust mufflers are generally packaged in the confined space available.

The catalytic converters are packaged inside the exhaust muffler. There are some drawbacks in this type of exhaust mufflers. Due to space limitation and size of catalytic converter, the outlet gases from the catalytic converter are directed towards the structural parts of the exhaust muffler such as side wall or shell. High velocity gases coming out of the catalytic converter generates the high frequency-low amplitude structural noise in the exhaust muffler assembly.

The gas flow coming from the catalytic converter outlet are with high amount of excitation. This excitations are further transferred to the exhaust muffler shell and structure which generates noise. It is required that these excitations are adequately channelized and diffused to avoid undesired noise.

It is also desirable to have an exhaust muffler having more efficient conversion and generates less back pressure.
OBJECTS OF THE INVENTION

It is an object of the present invention to provide an exhaust muffler for an internal combustion engine which generates less noise induced due to high velocity gases coming out from catalytic converter.

Yet another object of the present invention is to provide an exhaust muffler for an internal combustion engine which improves the Catalytic convertor conversion efficiency.

Yet another object of the present invention is to provide an exhaust muffler for an internal combustion engine which reduces the exhaust back pressure.

SUMMARY OF THE INVENTION

With such objects in view, the present invention provides an exhaust muffler for an internal combustion engine comprising: an inlet tube, at least a catalytic converter, plurality of baffles and a muffler shell,
wherein inlet end of catalytic converter is attached to the inlet tube and outlet end of catalytic converter is attached to a baffle and supported by shell of exhaust muffler,
and wherein an exhaust gas diverting element is provided at outlet end of catalytic converter .

The diverting element may be attached to the said catalytic converter at its outlet end.

An exhaust muffler according to an embodiment of the present invention wherein the said diverting element is attached to outlet end of the said catalytic converter in an angular direction, the angular direction is provided in such a way that the exhaust gas passing through the catalytic converter is diverted in that angular direction towards the larger area of the muffler and not towards the shell of the muffler. This avoids the flow of exhaust gas hitting the shell of muffler. Thus the structural noise generated due to hitting the exhaust gas to shell is eliminated.

An exhaust muffler according to an embodiment of the present invention wherein the said diverting element may be of conical shape or of any other shape for ex circular, elliptical etc. The diverting element may be converging or diverging shape which can divert the flow coming from the Catalytic converter in desired direction as mentioned above.

An exhaust muffler according to another embodiment of the present invention comprising a diffusing element, wherein the said diffusing element is located at outlet end of the said diverting element.

An exhaust muffler according to another embodiment of the present invention wherein the center line of said diverting element and center line of diffusing element substantially coincide with each other; so that the exhaust gas coming out from the catalytic converter through diverting element is diverted/channelized in the angular direction towards the center of diverting element and further the exhaust gases are diffused by the diffusing element in the larger area of the muffler.

An exhaust muffler according to another embodiment of the present invention wherein the center line of said diffusing element may be offset to the center line of diverting element in any direction.

A baffle may be provided at the other end of the diffusing element. Preferably the baffle is attached to shell of the muffler. The diffusing element may be mounted to the said baffle.

An exhaust muffler according to an embodiment of the present invention wherein the said diffusing element may be of conical shape or of any other shape for ex circular, elliptical etc. The diffusing element may be converging or diverging shape which can diffuse the gas flow coming from the diverting element in the larger area of the muffler as mentioned above.

An exhaust muffler according to another embodiment of the present invention wherein the said diffusing element and the baffle may have perforated holes to pass some part of exhaust gas through it to get improved diffusion effect.

An exhaust muffler according to another embodiment of the present invention wherein the exhaust muffler is an assembly of two halves wherein the diffusing element is provided in one half and the diverting element is provided in another half.

An exhaust muffler according to another embodiment of the present invention wherein the diffusing element and diverting element both may be provided in any one of the two halves of muffler.

DESCRIPTION OF DRAWINGS
In the drawings:

Figure 1a is an isometric view of an exhaust muffler of an internal combustion engine according to known prior art.

Figure 1b is a cut sectional view of the exhaust muffler of figure 1a showing the internal details.

Figure 2a is. a cut sectional view of an exhaust muffler of an internal combustion engine according to one embodiment of the invention.

Figure 2b is a close view of the exhaust muffler of figure 2a showing the internal details.
Figure 3a is. an isometric view of an exhaust muffler of an internal combustion engine according to another embodiment of the invention.

Figure 3b is a cut sectional view of the exhaust muffler of figure 3a showing the internal details.

Figure 4 shows views of exit cone of the exhaust muffler according to an embodiment of the invention.

Figure 5 shows. top views of top baffle of the exhaust muffler according to an embodiment of the invention.

Figure 6a & 6b shows view of diverting element of the exhaust muffler according to another embodiment of the invention.

Figure 7a & 7b shows assembly view of catalytic converter, diverting element and baffle of the exhaust muffler according to another embodiment of the invention.

Figure 8a & 8b shows isometric views of arrangements of diverting element and diffusing element of the exhaust muffler according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Description of preferred but non-limiting embodiments of the exhaust muffler of the present invention will now follow with reference to the above drawings.

Referring to figures 1a & 1b, there is shown an exhaust muffler 10 according to an existing prior art. The exhaust muffler 10 comprises inlet tube 11, catalytic converter 12, baffle 13, diffuser element/ plate 14 and muffler shell 15. Due to space limitation and size of catalytic converter, the outlet gases from the catalytic converter 12 are directed towards the structural parts of the exhaust muffler 10 such as side wall or shell 15. High velocity gases (as shown by arrows 16) coming out of the catalytic converter 12 generates the high frequency-low amplitude structural noise in the Muffler 10.

Normally diffuser element/ plate 14 may be used to diffuse the gas flow coming from the catalytic converter 12 outlet. This diffuser element/ plate 14 is mounted on the shell 15 of exhaust muffler 10. But this diffuser element/ plate 14 is less efficient to diffuse the high velocity gas induced excitation. This excitations are further transferred to the muffler shell 15 and structure which generates noise.

Referring now to Figures 2a, 2b and 4, there is shown an exhaust muffler 20 according to an embodiment of the invention, comprising inlet tube 11, catalytic converter 12, baffle 13 and diverting element in form of exit cone 21. As mentioned above the shape of diverting element may be of conical shape or of any other shape for ex circular, elliptical etc. The diverting element 21 may be converging or diverging shape, which can divert the flow coming from the Catalytic converter in desired direction as mentioned above. The exit cone 21 is attached to the outlet portion of catalytic converter 12 at baffle 13 . in an angular direction. The angular direction is provided in such a way that the exhaust gas passing through the catalytic converter 12 is diverted in that angular direction. The shape of this exit cone 21 is designed so that the outlet portion 22 of exit cone 21 is bent towards the upper side of exhaust muffler 20. Due to this arrangement, the exhaust gases coming out from catalytic converter 12 are diverted towards the outlet portion 22 of exit cone 21 and further diverted towards the larger area 26 of exhaust muffler as shown by arrows 23. This avoids the flow of exhaust gas hitting the shell 15 of exhaust muffler 20. Thus the structural noise generated due to hitting the exhaust gas to shell 15 is eliminated.

Referring now to figures 1a, 1b, 2a, 2b, 4 and 8a, in the prior art exhaust muffler 10, the exhaust gases coming out from catalytic converter 12 hit the muffler shell 15 which is located adjacent to it. This generates back pressure in the exhaust system. The catalytic converter 12 is mounted at an angle to inlet tube 11 of muffler 10. This arrangement makes most of the exhaust gas flow (as shown by arrows 17) travel through the rear/lower side of the catalytic converter 12 giving lower conversion efficiency.

In the exhaust muffler 20 as per an embodiment of the present invention, the exhaust gas flow coming from the catalytic converter 12 directed by exit cone 21 over a larger area (26) in the muffler 20 avoiding hitting to shell 15. This arrangement provides lower back pressure compared to prior art design. Also in the muffler 20, the exit cone outlet portion 22 is offset towards front side compared to catalytic convertor center 18. This arrangement forces the exhaust gas flow uniformly through the catalytic converter 12 (as shown by arrows 25) giving better conversion efficiency compared to prior art design.

Referring now to Figures 3a, 3b, 4, 5a, 6a and 8b, there is shown an exhaust muffler 30 according to another embodiment of the invention, comprising inlet tube 11, catalytic converter 12, baffle 13, exit cone 21, baffle 32 and a diffusing element in form of conical diffuser. The diffusing element 31 may be converging or diverging shape which can diffuse the gas flow coming from the diverting element 21 in the larger area (39) of the muffler 30 as mentioned above.The conical diffuser 31 is mounted on the baffle 32 such that the vertex 35 of conical diffuser 31 is towards the exit cone 21 and the center line 24 of exit cone 24 and the center line 34 of conical diffuser 31 are substantially coincide with each other. Due to this arrangement, the exhaust gases coming out from catalytic converter 12 and diverted by the exit cone 21 are hit on the conical diffuser 31 and diffused over a larger area (39) of exhaust muffler 30 as shown by arrows 35. This reduces the flow of exhaust gas hitting the baffle 32 of exhaust muffler 30. Thus the structural noise generated due to hitting the high velocity exhaust gas to baffle 32 is reduced.
As per another embodiment of the present invention, the conical diffuser 31 and the baffle 32 may have perforations 36 as shown in the figure 5b and 6b. Some part of exhaust gases coming out from exit cone 21 passes through these perforations 36. This arrangement further increases the diffusion of exhaust gases over a larger area (39) in the muffler 30.

Referring now to Figures 7a and 7b show an assembly catalytic converter 12, baffle 13 and exit cone 21 according to another embodiment of the invention. Normally this assembly is done by Tri-Welding which is difficult. The Tri-Welding may be avoided by welding the exit cone 21 to baffle 13 first and then welding the catalytic converter 12 to baffle 13. Additionally the exit cone 21 is located in desired position on baffle 13 with the help of lug 37 on exit cone 21 and corresponding locator 38 on baffle 38. The similar arrangement may be used for locating conical diffuser 31 on baffle 32.

As per another embodiment of the present invention, the exhaust muffler 30 is manufactured by joining two halves 30A and 30B. The conical diffuser 31 and baffle 32 are joined to first half 30A. The exit cone 21 and baffle 13 are joint to second half 30B. This arrangement confirms the alignment of exit cone 21 and conical diffuser 31 on the substantially same center line when these two halves 30A and 30 B are joint together.

Modifications and variations to the exhaust muffler described in this specification may be apparent to skilled readers. Such modifications and variations are deemed within the scope of the present invention. The applicant intends to rely on the provisional specification and drawings annexed to the provisional specification.
,CLAIMS:1. An exhaust muffler (20) of an internal combustion engine comprising:
An inlet tube (11), at least a catalytic converter (12), plurality of baffles (13) and a muffler shell (15),
wherein inlet end of catalytic converter (12) is attached to the inlet tube (11) and outlet end of catalytic converter (12) is attached to a baffle (13) and supported by shell (15) of exhaust muffler (20), and wherein an exhaust gas diverting element (21) is provided at outlet end of catalytic converter (12).

2. An exhaust muffler (20) of claim 1 wherein the said diverting element (21) is attached to outlet end of the said catalytic converter (12) in an angular direction, the angular direction is provided in such a way that the exhaust gas passing through the catalytic converter (12) is diverted in that angular direction towards the larger area (26) of the muffler (20) and not towards the shell (15) of the muffler.

3. An exhaust muffler (20) of claim 2 wherein the said diverting element (21) is of conical shape.

4. An exhaust muffler (20) of claim 2 wherein the said diverting element (21) is of any other shape for ex circular, elliptical etc.

5. An exhaust muffler (20) of claim 2 wherein the said diverting element (21) is converging or diverging shape which can divert the flow coming from the Catalytic converter (12) in desired direction.

6. An exhaust muffler (30) of claim 1 comprising: a diffusing element (31), wherein the said diffusing element (31) is located at outlet end (22) of the said diverting element (21).

7. An exhaust muffler (20) of claim 6 wherein the center line (34) of said diffusing element (31) and center line (24) of the said diverting element (21) substantially coincide with each other; so that the exhaust gas coming out from the catalytic converter (12) through diverting element (21) is diverted in the angular direction towards the center of diffusing element (31) and further the exhaust gases are diffused by the diffusing element (31) in the larger area (39 )of the muffler (30)

8. An exhaust muffler (30) of claim 7 the center line (34) of said diffusing element (31) is offset to the center line (24) of diverting element (21) in any direction.

9. An exhaust muffler (30) of claim 7 wherein a baffle (32) is provided at the other end of the diffusing element (31) and wherein the baffle (32) is attached to shell (15) of the muffler and wherein the diffusing element (31) is mounted to the said baffle (32).

10. An exhaust muffler (30) of claim 6 wherein the said diffusing element (31) is of conical shape.

11. An exhaust muffler (30) of claim 6 wherein the said diffusing element (31) is of any other shape for ex circular, elliptical etc.

12. An exhaust muffler (30) of claim 6 wherein the said diffusing element (31) is converging or diverging shape which can diffuse the flow coming from diverting element (21) in the larger area (39 )of the muffler (30).

13. An exhaust muffler (30) of claim 6 wherein the said diffusing element (31) and the baffle (32) is have perforated holes (36) to pass some part of exhaust gas through it to get improved diffusion effect.

14. An exhaust muffler (30) of claim 6 wherein the exhaust muffler (30) is an assembly of two halves (30 A, 30B) wherein the diffusing element (31) is provided in one half (30A) and the diverting element (21) is provided in another half (30B).

15. An exhaust muffler (30) of claim 11 wherein the diffusing element (31) and diverting element (21) both are provided in any one of the two halves of muffler.