FIELD OF INVENTION

This invention relates to an exhaust system for internal combustion engines, more particularly to an exhaust pipe having provision for enhanced cooling.

BACKGROUND OF THE INVENTION

During the operation of an Internal combustion engines hot exhaust gases produced must be discharged to the surroundings through an exhaust system. The exhaust system before discharging the exhaust gases to the surroundings passes the exhaust gases through a muffler that is connected to the exhaust port of engine via an exhaust pipe. As a result exhaust pipe connected to a vehicle engine becomes significantly hot.

Further, due to packaging requirements and space constraints the exhaust pipe is provided with bends and substantially curved sections along the length of the pipe. It has been observed that the temperature at outward circumferential wall of the pipe at the curved section or bends becomes relatively high as compared to the temperature at the inward circumferential wall of the pipe owing to the flow characteristics of the exhaust gases. This temperature difference may cause plurality of problems such as paint peel off or even thermal failure.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an inlet pipe with the provision of enhanced cooling at the curved sections or the bends. In an embodiment of the invention an extended surface is provided at the curved sections or the bends that sinks the excessive heat and provides larger surface area for the dissipation of heat.

In another embodiment a gas tight detachable joining means is provided at the curved section that provides extended surface for heat sink and dissipation wherein, the pipe downstream of the joint can be integrated with the muffler, thus eliminating need of a separate joint at muffler end.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts a frame of a three-wheeled vehicle having an exhaust system mounted.

Figure 2 depict in detail the exhaust system of the vehicle shown in Figure 1.

Figure 3 depicts a configuration of an exhaust pipe.

Figure 4 depicts an exhaust pipe as per an embodiment of the invention.

Figure 5, 6 and 7 shows an exhaust pipe as per another embodiment of the invention.

Figure 8 depicts a graph comparing exhaust pipe of prior art and the exhaust pipe as per a preferred embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 1 depicts a frame of a three-wheeled motor vehicle 01 defining a passenger cabin 02 an operator's cabin 03 having an engine 04 secured to the rear portion of frame and a muffler 06 connected to the engine 04 through an exhaust pipe 05.

Figure 2 and Figure 3 depicts in detail the muffler 06 along with the exhaust pipe 05 shown in vehicle 01 illustrated above. During the operation of the engine 04 hot exhaust gases produced are discharged to the surroundings through the exhaust muffler 06 that is connected to the exhaust port of engine 04 through said exhaust pipe 05 wherein, one end of the said exhaust pipe 05 is being adapted for connection to an engine exhaust port termed as exhaust end 07 and the other end being adapted for connection to the muffler termed as muffler end 08, the internal periphery of the exhaust pipe 05 provides a passageway for exhaust form the exhaust port to the muffler 06, said exhaust pipe 05 has a non-linear longitudinal axis, such that the exhaust gases passing through the exhaust pipe 05 travels a substantially curved flow path moving from the exhaust port to the muffler 06. Alternative constructions of the intake manifold 05 may include any of a number of different configurations, in which the longitudinal axis of the intake passageway is substantially actuate or curved at various sections.

It has been observed that the temperature at outward circumferential wall 10 of the pipe at the curved section becomes relatively high as compared to the temperature at the inward circumferential wall 09 of the exhaust pipe 05 owing to the flow characteristics of the exhaust gases.

As shown in Figure 4, in an embodiment of the present invention an extended surface 11 is provided on the circumference of the exhaust pipe 05, at the curved section that sinks the excessive heat and also provides larger surface area for the dissipation of heat.

As shown in Figure 5, Figure 6 and Figure 7, in another embodiment of the invention the pipe is split at the curved section, into a muffler end pipe 12 and an exhaust end pipe 13 and a gas tight detachable joining means is provided to join the split ends together. The joint is made of heat conductive material that provides extended surface for heat sink and dissipation wherein, the muffler end pipe 12 can also be integrated with the muffler 06. In the present embodiment said gas tight detachable joining means comprises first hollow-formed sealing flange 14 mounted around or welded to the split end of the muffler end pipe 12 and second hollow-formed sealing flange 15 mounted around or welded to the split end of the exhaust end pipe 13 at the curved section. Said hollow-formed sealing flange 14, 15 are mirror-symmetrical in relation to a plane perpendicular to the radial plane and passing through the centre of the curvature of the curved section. The flanges 14, 15 having a flat outside edge running in said plane along the cross-section of the curve have extended edges 14A, 14B beyond the circumference. The extended edges further comprises of plurality of holes, said flat outside extended edges being placed on each other and fastened through bolt and nut received through said holes as an example bolt 17 and nut 16, so that the hollow-formed sealing flange together form a continuous exhaust passage at the curved section.

Figure 8 depicts a graph that shows the reduction in temperature at the outward circumferential wall 10 of the curved section of the intake pipe 05. As can be seen the temperature with extended surface depicted by the plot 18 is lesser at least by 70 degree Celsius compared to the temperature at the outward circumferential wall 10 of the curved section without extended surface depicted by plot 19. This results in reduction of temperature difference between the outward circumferential wall 10, and the inward circumferential wall 09 at the curved section of the exhaust manifold 05.

The extended surface also increases structural stability and can be placed anywhere within 30 percent of the circumference of the curve on either side of the radial plane of symmetry based on the requirements and is made of heat conductive material.

It should be understood that the foregoing description is that of a preferred embodiment of the invention and that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims. Further any shape and configuration of the extended surface is possible within the ambit of appended claims.

WHAT IS CLAIMED IS:

1. An exhaust pipe for an internal combustion engine comprising;

an exhaust conduit having an exhaust passage and at least one substantially curved section along longitudinal axis of said exhaust passage; and

an extended surface provided at each curved section to enhance heat dissipation and structural rigidity;

wherein, a first end of said exhaust conduit being adapted for connection to an engine exhaust port and a second end being adapted for connection to a muffler.

2. The exhaust pipe, as claimed in claim 1, wherein the extended surface is a gas tight detachable joining means.

3. The exhaust pipe, as claimed in claim 2, wherein said gas tight detachable joining means comprises a plurality of hollow-formed sealing flange means secured on said exhaust conduit.

4. The exhaust pipe, as claimed in claim 3, wherein the plurality of hollow-formed sealing flange means are made of heat conductive material.

5. The exhaust pipe, as claimed in claim 3, wherein said plurality of hollow-formed sealing flange means comprising multiple mirror symmetrical hollow sealing flanges such that the hollow sealing flanges lies in a first plane perpendicular to the radial plane.

6. The exhaust pipe, as claimed in claim 4, wherein said first plane passes through the curved section of the exhaust conduit having a plurality of flat outside edges such that the plurality of flat outside edges lies in said first plane along the cross section of said curved section.

7. The exhaust pipe, as claimed in claim 5, wherein said plurality of outside edges is configured to facilitate the plurality of hollow-formed sealing flange means to form a continuous exhaust passage at the curved section.

8. The exhaust pipe, as claimed in claim 1, wherein the second end is adapted for connection of said exhaust conduit to the muffler is integrated with said muffler.

9. The exhaust pipe, as claimed in claim 1, wherein the extended surface is provided within 30 percent of the circumference of the curve on either side of the radial plane of symmetry.