Claims:We Claim:
1. An exhaust system 500 for an internal combustion engine, the exhaust system 500 comprising:
an inlet pipe 100 for receiving an exhaust gas flow from the engine, the inlet pipe 100 comprises an upper portion 110, a middle portion 120 and a lower portion 130, the upper portion 110 and the lower portion 130 has perforations for directing and guiding the exhaust gas flow towards an after-treatment unit 200;
wherein the middle portion 120 of the inlet pipe 100 has a reduced cross-sectional area than the upper portion 110 and the lower portion 130 which enables the middle portion 120 to control the exhaust flow entering the inlet pipe 100 for facilitating a uniform flow distribution of the exhaust gas towards the after-treatment unit 200.

2. The exhaust system 500 as claimed in claim 1, wherein an outlet end of the upper portion 110 of the inlet pipe 100 forms a converging section 118 and an inlet end of the lower portion 130 of the inlet pipe 100 forms a diverging section 128 for defining the middle portion 120 of the inlet pipe 100 as a venturi gap 138 for facilitating a uniform flow distribution of the exhaust gas from the perforations of the upper portion 110 and the lower portion 130 of the inlet pipe 100 towards the after treatment unit 200.

3. The exhaust system 500 as claimed in claim 1, wherein the inlet pipe 100 is arranged transversely to an exhaust housing 510.
4. The exhaust system 500 as claimed in claim 1, wherein the after-treatment unit 200 comprises a substrate 210.

5. The exhaust system 500 as claimed in claims 1 and 4, wherein the perforations on the upper portion 120 of the inlet pipe 100 allow the exhaust gas flow to disperse at an upper half of the substrate 210 and perforations on the lower portion 130 of the inlet pipe 100 allow the exhaust flow to disperse at a bottom half of the substrate 210 for facilitating a uniform flow distribution of the exhaust gas towards the after-treatment unit 200.

6. The exhaust system 500 as claimed in claim 1, wherein the after treatment unit 200 includes a Diesel Oxidation Catalysts (DOC) as the substrate 210, a Diesel Particulate Filters (DPF) 220, a Selective Catalytic Reduction (SCR) catalyst chamber 230, and a mixing tube 240.
, Description:Field of the Invention

[0001] The present invention relates to an exhaust system for an internal combustion engine. More particularly, the present invention relates to a radial exhaust system for an internal combustion engine.

Background of the Invention

[0002] An engine exhaust system routes exhaust gas from the engine and exhausts it into the environment. While exhausted to the environment, the system provides noise attenuation and after treatment of the exhaust gases so to prevent environment pollution. A typical exhaust systems may include an inlet pipe, an after treatment unit and an outlet. The after treatment unit may include a substrate positioned within a housing of the exhaust system. Further, the flow distribution of the exhaust gas plays a vital role in the after treatment of the exhaust gas to prevent the exhaust of toxic substances to the environment. If the flow distribution is uniform throughout the exhaust system, the substrate reduces the exhaust gases to less toxic substances by way of catalysed chemical reactions in a more efficient way.
[0003] Further, to enhance enough swirl/turbulence for the exhaust flow entering the system such that flow distribution over substrate face should be uniform, especially for radial inlet systems. Placing perforated plate/pipe upstream of substrate is a conventional approach but it has limitation in distributing flow over the top half of the substrate especially for radial inlet exhaust system.

[0004] Therefore there is a requirement of an exhaust system for an internal combustion engine which overcomes few or all drawbacks of the existing radial exhaust systems.

Objects of the Invention

[0005] An object of the present invention is to provide an exhaust system for an internal combustion engine.

[0006] Another object of the present invention is to provide is to provide an exhaust system for an internal combustion engine, which facilitates a uniform flow distribution of exhaust gas.

[0007] Yet another object of the present invention is to provide an exhaust system for an internal combustion engine, which enhances enough swirl/turbulence for the exhaust flow entering the system such that flow distribution over substrate face should be uniform, especially for radial inlet systems.

[0008] One more object of the present invention is to provide an exhaust system for an internal combustion engine, which is economical and robust in construction.
Summary of the invention

[0009] According to the present invention, an exhaust system for an internal combustion engine in accordance with the present invention is provided. In the present embodiment, the exhaust system is a radial exhaust system. The exhaust system includes an inlet pipe, an after treatment unit and an outlet pipe. The inlet pipe receives an exhaust gas flow from a combustion chamber of the internal combustion engine towards the exhaust system. The exhaust system prevents the release of toxic substances towards the environment by purifying the emission gas from the combustion chamber. The after treatment unit include a substrate positioned within a housing of the exhaust system. The substrate 210 is a Diesel Oxidation Catalysts (DOC).

[0010] In the present embodiment, the after treatment unit includes a Diesel Particulate Filters (DPF), a Selective Catalytic Reduction (SCR) catalysts chamber and a mixing chamber. The inlet pipe is arranged transversely to the exhaust housing such that the exhaust flow entering the exhaust system is perpendicular to the axis of the substrate configured therein. The inlet pipe ensures enough swirl/turbulence for the exhaust flow entering the exhaust system such that flow distribution over the substrate face is uniform. In the present embodiment, the inlet pipe includes an upper portion, a middle portion and a lower portion. The upper portion and the lower portion has perforations for directing and guiding the exhaust flow towards the after treatment unit. In the present embodiment, the middle portion of the inlet pipe has a reduced cross sectional area than the upper portion and the lower portion. Specifically, an outlet end of the upper portion of the inlet pipe forms a converging section and an inlet end of the lower portion of the inlet pipe forms a diverging section for defining the middle portion of the inlet pipe as a venturi gap. The venturi gap facilitates a uniform flow distribution of the exhaust gas from the perforations of the upper portion and the lower portion of the inlet pipe towards the after treatment unit.

[0011] The reduced cross section in the middle portion or the venturi gap controls the exhaust flow entering the inlet pipe for facilitating a uniform flow distribution of the exhaust gas towards the after-treatment unit. The velocity of exhaust flow increases at the venturi gap which allows the exhaust flow from the upper portion to reach the lower portion and dispersing the exhaust uniformly through the respective perforations.

Brief Description of the Drawings

[0012] The advantages and features of the present invention will be understood better with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

[0013] Figure 1 illustrates a schematic representation of an exhaust system for an internal combustion engine in accordance with the present invention;

[0014] Figure 2 illustrates a perspective view of figure 1;

[0015] Figure 3 illustrates a schematic representation of the arrangement of an inlet pipe inside the exhaust system; and

[0016] Figure 4 illustrates flow distribution of exhaust from the inlet pipe inside the exhaust system.

Detailed Description of the Invention

[0017] An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising, "having, "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0018] The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “an” and “a” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0019] The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms.

[0020] Referring to figures 1 and 2, an exhaust system 500 for an internal combustion engine in accordance with the present invention is illustrated. In the present embodiment, the exhaust system 500 is a radial exhaust system as shown in figure 1. The exhaust system 500 includes an inlet pipe 100, an after treatment unit 200 and an outlet pipe 300. The inlet pipe 100 receives an exhaust gas flow from a combustion chamber (not shown) of the internal combustion engine towards the exhaust system 500. The exhaust system 500 prevents the release of toxic substances towards the environment by purifying the emission gas from the combustion chamber.

[0021] The after treatment unit 200 include a substrate 210 positioned within a housing 510 of the exhaust system 500. The substrate 210 captures solid particulates from the emission gas thereby reducing the exhaust gases to less toxic substances by way of catalysed chemical reactions. In the present embodiment, the substrate 210 is a Diesel Oxidation Catalysts (DOC).

[0022] By way of non-limiting example, the after treatment unit 200 further includes a Diesel Particulate Filters (DPF) 220, a Selective Catalytic Reduction (SCR) catalysts chamber 230 and a mixing chamber 240. The substrate 210 captures solid particulates and are oxidised using oxidation catalysts. Thereafter, the diesel particulate filters 220 reduces the diesel particulate matter or soot from the exhaust gas. Further, the exhaust gas is emitted to the environment after the purifying treatment from the mixing chamber 240 and the Selective Catalytic Reduction chamber 230 inside the exhaust system 500.

[0023] Referring now to figures 3 and 4, the exhaust housing 510 has an opening 510a which allows the inlet pipe 100 to partially configure within the exhaust housing 510. Specifically, the inlet pipe 100 is arranged transversely to the exhaust housing 510 such that the exhaust flow entering the exhaust system 500 is perpendicular to the axis of the substrate 210 configured therein. The substrate 210 is arranged adjacent to the inlet pipe 100 inside the exhaust housing 510. The inlet pipe 100 ensures enough swirl/turbulence for the exhaust flow entering the exhaust system 500 such that flow distribution over substrate 210 face is uniform.

[0024] In the present embodiment, the inlet pipe 100 includes an upper portion 110, a middle portion 120 and a lower portion 130. The upper portion 110, and the lower portion 130 has perforations for directing and guiding the exhaust flow towards the after treatment unit 200. The upper portion 110 has an outlet end to direct the exhaust flow towards the lower portion 130 and the lower portion 130 has an inlet end to receive the flow from the upper portion 110. In the present embodiment, the middle portion 120 of the inlet pipe 100 has a reduced cross sectional area than the upper portion 110 and the lower portion 130. Specifically, the outlet end of the upper portion 110 of the inlet pipe 100 forms a converging section 118 and the inlet end of the lower portion 130 of the inlet pipe 100 forms a diverging section 128 for defining the middle portion 120 of the inlet pipe 100 as a venturi gap 138 as shown in figure 3. The venturi gap 138 facilitates a uniform flow distribution of the exhaust gas from the perforations of the upper portion 110 and the lower portion 130 of the inlet pipe 100 towards the after treatment unit 200.

[0025] Referring to figure 4, the reduced cross section in the middle portion 120 or the venturi gap 138 controls the exhaust flow entering the inlet pipe 100 for facilitating a uniform flow distribution of the exhaust gas towards the after-treatment unit 200. The velocity of exhaust flow increases at the venturi gap 138 which allows the exhaust flow from the upper portion 110 to reach the lower portion 130 and dispersing the exhaust uniformly through the respective perforations. The venturi gap 138 allow some amount of flow to pass through the upper half of the substrate 210 and remaining flow disperse at bottom half of the substrate 210 through perforated holes in the lower portion 130 to develop a uniform flow distribution over the substrate 210 face.

[0026] Specifically, the upper portion 110 of the inlet pipe 100 has perforations which allows the exhaust flow to disperse at an upper half of the substrate 210 and similarly in the lower portion 130.

[0027] Therefore the present invention has an advantage of providing the exhaust system 500 for an internal combustion engine, which facilitates a uniform flow distribution of exhaust gas. The exhaust system 500 enhances enough swirl/turbulence for the exhaust flow entering the exhaust system 500 such that flow distribution over the substrate 210 face is uniform, especially for radial inlet systems. Further, the exhaust system 500 is economical and robust in construction.

[0028] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the scope of the claims of the present invention.