WO2019092744A1

WO2019092744A1 - Exhaust system

Info

Publication number: WO2019092744A1
Application number: PCT/IN2018/050724
Authority: WO
Inventors: Sandeep Kumar BAWASKAR; Pankaj TURKAR
Original assignee: Hero Motocorp Ltd
Current assignee: Hero Motocorp Ltd
Priority date: 2017-11-09
Filing date: 2018-11-08
Publication date: 2019-05-16
Anticipated expiration: 2020-05-09

Abstract

An exhaust system (300) of an internal combustion engine (8) comprises an exhaust pipe (311), a catalyst device (305) and a muffler (306) wherein the exhaust pipe (311) comprises of a first exhaust pipe (301) and a second exhaust pipe (304). An exhaust shield (303) configured to shield the catalyst device (305) and at least a portion of the first exhaust pipe (301). The exhaust shield (303) comprises a plurality of exhaust shield elements (313, 323). which are joined together to form a tubular exhaust shied (303) around a portion of the exhaust system (300).

Description

EXHAUST SYSTEM

FIELD OF THE TECHNOLOGY

[01] The present invention relates to an internal combustion engine and, more particularly, relates to exhaust system of the internal combustion engine of a vehicle.

BACKGROUND

[02] An exhaust system of an internal combustion engine of a saddle type vehicle is known where a catalyst device is mounted on the downstream side of the exhaust port of the internal combustion engine. Generally, the catalyst device is disposed in the exhaust path at a distance from the exhaust port of the internal combustion engine. As the exhaust pipe portion between the exhaust port of the engine and the catalyst device is directly exposed to the outside atmosphere there is a loss of heat from the exhaust gases. Hence, the temperature of the exhaust gases received at catalyst device may not be enough for efficient performance of the catalytic conversion.

[03] Generally, the exhaust pipe extends horizontally from the exhaust port of the engine and then is bent to form a substantial vertical section, the catalyst device is disposed in the vertical section of the exhaust pipe. A double structured exhaust pipe having an inner pipe and an outer pipe surrounding the inner pipe to avoid heat losses from the exhaust pipe are known. Since, the exhaust pipe has a bent portion after the exhaust port of the internal combustion engine, the double structured exhaust pipe is to be provided with a bend, the outer surface of the double structured exhaust pipe forms wrinkles around the inner circle of the bent portion of the exhaust pipe which is not desirable. To address this, sometimes, the pipe is bent with a bigger bend radius, however, such bent pipe having bigger radius requires more curved portion along the length of the pipe and hence has lesser straight portion along the vertical direction to accommodate a catalyst. Similarly, bigger diameter of the outer pipe than the diameter of inner exhaust pipe resulting in more wrinkles around the inner circle of the bent portion. SUMMARY

[04] In one aspect of the present invention, an internal combustion engine comprising an exhaust port and an exhaust system, wherein exhaust system comprises an exhaust pipe, a catalyst device, a muffler and an exhaust shield. In an embodiment, the internal combustion engine (8) comprises a crankcase (04), a cylinder block (06) coupled to an upper portion of the front end of the crankcase (04) and projecting upwardly and forwardly therefrom. The exhaust pipe comprises a first exhaust pipe having a first exhaust pipe upstream end and a first exhaust pipe downstream end, wherein the first exhaust pipe upstream end is operatively coupled to the exhaust port and a second exhaust pipe having a second exhaust pipe upstream end and a second exhaust pipe downstream end. The catalyst device having a catalyst device upstream end and catalyst device downstream end, wherein the catalyst device upstream end coupled to the first exhaust pipe downstream end and the catalyst device downstream end coupled to the second exhaust pipe upstream end. The muffler coupled to the second exhaust pipe downstream end. The exhaust shield is configured to shield the catalyst device and at least a portion of the first exhaust pipe, wherein the exhaust shield comprises a plurality of exhaust shield elements. This enables easy manufacturing of the tubular exhaust shield that covers the catalyst device and the exhaust pipe. Since, the diameter of the catalyst device is different than the exhaust pipe, the manufacturing of the tubular exhaust shield with a single pipe is otherwise cumbersome.

[05] In an embodiment, the plurality of exhaust shield elements are manufactured by stamping process and are coupled together along the longitudinal edges to form a tube shaped exhaust shield. The tubular structure surround the catalyst device and at least portion of the exhaust pipe so as to reduce the heat loss of the exhaust gases.

[06] In an embodiment, the first exhaust pipe has a curved portion between the first exhaust pipe upstream end and the first exhaust pipe downstream end. The plurality of exhaust shield elements comprise a curved portion configured to shield a curved portion of the first exhaust pipe. The plurality of exhaust shield elements are manufactured by forming or pressing method to attain the curved shape. The exhaust shield, formed by coupling these plurality of exhaust shield elements, has a curved portion without any wrinkles around the curved portion of the exhaust shield. In an embodiment, the plurality of exhaust shield elements are semi cylindrical in shape.

[07] In another embodiment of the present invention the exhaust shield has a variable diameter along the length of the exhaust shield so as to conform the portion of the exhaust system which is shielded by the exhaust shield.

[08] In an embodiment of the present invention, the exhaust shield comprises of a shield upstream end and a shield downstream end, wherein the shield upstream end of the exhaust shield is welded to the outer surface of the first exhaust pipe and the shield downstream end of the exhaust shield is welded to the second exhaust pipe.

[09] In an embodiment of the present invention, wherein the substantial gap between the outer surface of the first exhaust pipe and the inner surface of the exhaust shield and the substantial gap between the outer surface of the catalyst device and the inner surface of the exhaust shield are filled with a heat insulating material to avoid loss of heat from the exhaust system to the atmosphere, hence sufficient amount of heat will be available for the process of catalytic conversion and will eventually result in better purification of exhaust gases.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[10] The invention itself, together with further features and attended advantages, will become apparent from consideration of the following detailed description, taken in conjunction with the accompanying drawings. One or more embodiments of the present invention are now described, by way of example only, with reference to the accompanying drawing wherein like reference numerals represent like elements and in which: [11] Figure 01 illustrates a side view of the vehicle according to an embodiment of the invention;

[12] Figure 02 illustrates a view of an exhaust system of an internal combustion engine of the vehicle according to an embodiment of the invention;

[13] Figure 03 illustrates an exploded view of a portion of the exhaust system of the internal combustion engine of the vehicle according to an embodiment of the invention; and

[14] Figure 04 illustrates sectional view of a portion of the exhaust system of the internal combustion engine of the vehicle according to an embodiment of the invention.

[15] The drawings referred to in this description are not to be understood as being drawn to scale except if specifically noted, and such drawings are only exemplary in nature.

DETAILED DESCRIPTION

[16] While the invention is susceptible to various modifications and alternative forms, an embodiment thereof has been shown by way of example in the drawings and will be described here below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternative falling within the spirit and the scope of the invention.

[17] The term "comprises", comprising, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, structure or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or structure or method. In other words, one or more elements in a system or apparatus proceeded by "comprises... a" does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus. [18] For better understanding of this invention, reference would now be made to the embodiment illustrated in the accompanying Figures and description here below, further, in the following Figures, the same reference numerals are used to identify the same components in various views.

[19] While the present invention is illustrated in the context of a saddle riding type vehicle, however, the exhaust system of an internal combustion engine and aspects and features thereof can be used with other type of vehicles as well. It is to be noted that terms such as "two wheeled vehicle" and "vehicle" are interchangeably used throughout the description. The term "two wheeled vehicle" includes vehicles such as motorcycles, scooters, bicycles, mopeds, scooter type vehicle, all-terrain vehicles (ATV) and the like.

[20] The terms "front / forward", "rear / rearward / back / backward", "up / upper / top", "down / lower / lower ward / downward, bottom", "left / leftward", "right / rightward" used therein represents the directions as seen from a vehicle driver sitting astride and these directions are referred by arrows Fr, Rr, U, Lr, L, R in the drawing Figures.

[21] Referring to Figure 01, a vehicle (100) according to an embodiment of the present invention is depicted. The vehicle (100) referred to herein, embodies a motorcycle. Alternatively, the vehicle (100) may embody any other ridden vehicles such as scooters, three-wheeled vehicle, all-terrain vehicles (ATV) etc. without limiting the scope of the invention.

[22] Figure 01 is a side view of a two-wheeled vehicle (100) which incorporates an internal combustion engine, according to an embodiment of the present invention. The two wheeled vehicle (100) comprises, inter-alia, a front fork (112), head pipe (207), a front fender (106), a front wheel (108), a headlight (110), a steering handle bar (132), a fuel tank (102), an internal combustion engine (02), exhaust system (300), a rear suspension (118), a rear wheel (126), a rear fender (128), a tail light (130), and a seat (104). It may be noted that the vehicle is shown to have include above stated parts, however the vehicle includes other parts which may not be relevant for explaining the present invention and hence are not shown and described. [23] The front fork (112) is rotatably attached to the head pipe (207) enabling free steering. The front fork (112) supports a front wheel (108) at lower end thereof and a steering handle bar (132) at upper end thereof. A fuel tank (102) storing fuel is mounted on a two wheeled vehicle (100) at a position upper than the internal combustion engine (02). The rear wheel (126) is covered from above by a rear fender (128) which is mounted onto the rear end portion of seat member (104). The rear wheel suspension section includes a swing arm (not shown) supporting a rear wheel (126) and at least one rear suspension (118) attached between the swing arm and the seat rail member (104). A tail lamp assembly (130) is mounted on the rear fender (128).

[24] The internal combustion engine (02) is mounted on the two-wheeled vehicle (100). The internal combustion engine (02) is disposed in a space below the fuel tank (102) and behind the front fork (112). A transmission (not shown) is arranged behind the internal combustion engine (02) to transmit the power output from the internal combustion engine (02) to the rear wheel (126) via a transmission means. The internal combustion engine (02) is comprising of a crankcase (04), a cylinder block (06) coupled to an upper portion of the front end of the crankcase (04) and projecting upwardly and forwardly therefrom, and a cylinder head (08) coupled to an upper end of the cylinder block (06). The cylinder head (08) has a combustion chamber faced by top surface of the piston, an intake port (40) communicating with the combustion chamber and opening at a first surface of the cylinder head (08), and an exhaust port (42) communicating with the combustion chamber and opening at a second surface of the cylinder head (08). The exhaust system (300) is coupled to the exhaust port (42) of the internal combustion engine (02).

[25] The exhaust system (300), as shown in the Figure 02 and Figure 03, comprising an exhaust pipe (311), a catalyst device (305), a muffler (306) and an exhaust shield (303). The exhaust pipe (311) comprises of a first exhaust pipe (301) and a second exhaust pipe (304). The first exhaust pipe (301) has a first exhaust pipe upstream end (301a) and a first exhaust pipe downstream end (301b). The catalyst device (305) has a catalyst device upstream end (305a) and catalyst device downstream end (305b). The first exhaust pipe upstream end (301a) of the first exhaust pipe (301) is fluidicaly coupled to the exhaust port (42) of the internal combustion engine (02). The first exhaust pipe (301) extends substantially horizontal from the exhaust port (42) forming a horizontal portion (301h) [refer Figure 02] of the first exhaust pipe (301); and thereafter the first exhaust pipe (301) bends downwards and extends substantially vertical along the front face of the internal combustion engine (02) forming vertical portion (301v) [refer Figure 02] of the first exhaust pipe (301). The first exhaust pipe downstream end (301b) of the first exhaust pipe (301) is coupled to the catalyst device upstream end (305a) of the catalyst device (305). The first exhaust pipe (301) comprises of a curved portion between the first exhaust pipe upstream end (301a) and the first exhaust pipe downstream end (301b).

[26] The second exhaust pipe (304) has a second exhaust pipe upstream end (304a) and a second exhaust pipe downstream end (304b). The second exhaust pipe (304) is coupled to the catalyst device (305). The second exhaust pipe (304) is coupled to the catalyst device (305) by joining the second exhaust pipe upstream end (304a) of the second exhaust pipe (304) to the catalyst device downstream end (305b) of the catalyst device (305). The second exhaust pipe (304) then extends towards rear of the vehicle (100). The second exhaust pipe downstream end (304b) of the second exhaust pipe (304) is coupled to the muffler (306) towards rear of the vehicle (100).

[27] As illustrated in the Figure 03, in accordance with an embodiment of the present invention, an exploded view of parts of the exhaust system (300) are shown, without limiting the scope of the invention, wherein the catalyst device (305) is comprising of a honeycomb like structure inside it. The catalyst device (305) is shown to comprise of two conical structures as a first conical structure (302a) and a second conical structure (302b). The first conical structure (302a) is fixed to the first end of the catalyst device (305) and the second conical structure (302b) is fixed to the second end of the catalyst device (305). The converging end of the first conical structure (302a) forms the catalyst device upstream (305a). The converging end of the second conical structure (302b) forms the catalyst device downstream end (305b).

[28] As illustrated in the Figure 02, 03 and 04, at least portion of the exhaust system (300) is surrounded by the exhaust shield (303). As illustrated in the exemplary embodiment, the at least portion of the exhaust system (300) is comprising of at least portion of the first exhaust pipe (301) and the catalyst device (305). This portion of the exhaust system (300) is surrounded by an exhaust shield (303), the at least portion of the first exhaust pipe (301) is a part of the horizontal portion (301h) of the first exhaust pipe (301), without limiting the scope of the invention. As illustrated in the exemplary embodiment, the at least portion of the exhaust system (300) is comprising of the first exhaust pipe (301) and the catalyst device (305). This portion of the exhaust system (300) is surrounded by an exhaust shield (303), without limiting the scope of the invention. In an embodiment, the at least portion of the exhaust system (300) comprises of the first exhaust pipe (301), the second exhaust pipe (304) and the catalyst device (305). This portion of the exhaust system (300) is surrounded by an exhaust shield (303), without limiting the scope of the invention.

[29] The exhaust shield (303) is a tubular body that surround a portion of the exhaust pipe (311). The exhaust shield (303) comprises of a plurality of shell like structures (313, 323, ... ). A plurality of shell like structures (313, 323, ... ) hereinafter interchangeably also referred to as exhaust shield elements (313, 323, ... ) for the illustration of this invention. The plurality of exhaust shield elements (313, 323) are coupled together to form the exhaust shield (303). In an embodiment of the present invention, the plurality of the exhaust shield elements (313, 323) are welded together to form the exhaust shield (303). As depicted in the Figure 03, the plurality of exhaust shield elements (313, 323) are coupled along the longitudinal edges so as to form a tubular structure of the exhaust shield (303). In an embodiment, the tubular structure of the exhaust shield (303) is formed such that it has variable diameter along its length so as to conform the outer surface of the portion of the exhaust system (300) which is shielded by the plurality of the exhaust shield elements (313, 323, ... ).

[30] Thus, it is evident that if the portion of the exhaust system (300) has a curved portion, then the plurality of exhaust shield elements (313, 323, ... ) will also be curved so as to confirm the curved portion of the exhaust system (300). In the exemplary illustration of the present invention, the first exhaust pipe (301) comprises of a curved profile between the first exhaust pipe upstream end (301a) and the first exhaust pipe downstream end (301b) and the catalyst device (305) is disposed aligning with the vertical portion of the first exhaust pipe (301). Hence, the plurality of exhaust shield elements (313, 323, ... ) are also shaped so as to confirm the curved portion of the first exhaust pipe (301) and the catalyst device (305). Once such plurality of exhaust shield elements (313, 323, ... ) are joined together to form a tubular curved portion and a longitudinal portion so that the tubular curved portion confirms the curved portion of the first exhaust pipe (301) and the longitudinal portion confirms the catalyst device (305).

[31] The exhaust shield (303) has a shield upstream end (303a) and a shield downstream end (303b), wherein the shield upstream end (303a) of the exhaust shield (303) is coupled to the first exhaust pipe (301) near to its first exhaust pipe upstream end (301a) and the shield downstream end (303b) of the exhaust shield (303) is coupled to the second exhaust pipe (304) near to its second exhaust pipe upstream end (304a).

[32] The tubular structure of the exhaust shield (303) formed by joining plurality of exhaust shield elements (313, 323, ... ) provides a covering to the first exhaust pipe (301) and the catalyst device (305) to prevent loss of heat from the exhaust gases coming from exhaust port (42) and entering the catalyst device (305). Hence sufficient amount of heat will be available for the process of catalytic conversion and will eventually result in better purification of exhaust gases.

[33] The tubular structure of the exhaust shield (303) formed by joining the plurality of exhaust shield elements (313, 323, ... ) provides a covering to the first exhaust pipe (301) and the catalyst device (305) so as to prevent heat losses of the exhaust gases coming from exhaust port (42). Hence, the exhaust shield (303) will act as an insulator between the atmosphere and the exhaust gases in the first exhaust pipe (301) and excess heat in the first exhaust pipe (301) will not hurt the legs or any other body parts of the rider.

[34] In an embodiment of the present invention, as illustrated in the Figure 04 (Sectional view of the exhaust system), the exhaust shield elements (313, 323, ... ) are surrounding the first exhaust pipe (301) and the catalyst device (305), a cavity (310a) is formed in between the inner surface of the exhaust shield elements (313a, 313b) and the portion of the first exhaust pipe (301) and another cavity (310b) is formed in between the inner surface of the exhaust shield elements (313b, 323b, ... ) and the outer surface of the catalyst (305). These cavities (310a, 310b) are filled with a heat insulator to further avoid heat losses to the atmosphere and also to protect legs of the rider from excess heat in the first exhaust pipe (301).

[35] In an embodiment of the present invention, at least one of the plurality of exhaust shield elements (313, 323, ... .) is manufactured by stamping, pressing, or forming of a metal sheet / plate to form the curved shape, as shown in the Figure 03, confirming to the curved profile of the first exhaust pipe (301) between the first exhaust pipe upstream end (301a) and the first exhaust pipe downstream end (301b) and to the catalyst device (305), and the plurality of the exhaust shield elements (313, 323, ...) are joined together along the longitudinal edges to form a tube shaped exhaust shield (303) with the curved profile. Hence these exhaust shield (303) provide a curved profile with required radius while not resulting any wrinkles on the outer surface of the exhaust shield (303) and this exhaust shield (303) provides enough vertically straight portion to accommodate a catalyst device (305) inside the exhaust shield (303) without resulting any wrinkles on the outer surface of the exhaust shield (303). Hence by using stamping and pressing process to attain the curved profile of the exhaust shield (303), the wrinkles resulting by bending process can be avoided. In an embodiment, the plurality of exhaust shield elements (313, 323, ....) are semi cylindrical in shape. In an embodiment, the plurality of exhaust shield elements (313, 323, ... .) are of suitable shape.

[36] While few embodiments of the present invention have been described above, it is to be understood that the invention is not limited to the above embodiments and modifications may be appropriately made thereto within the spirit and scope of the invention.

[37] While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

Claims

We claim:

1. An internal combustion engine (8) comprising:

an exhaust port (42);

an exhaust system (300) comprising:

an exhaust pipe (311) comprising:

a first exhaust pipe (301) having a first exhaust pipe upstream end (301a) and a first exhaust pipe downstream end (301b), wherein the first exhaust pipe upstream end (301a) is operatively coupled to the exhaust port (42); and

a second exhaust pipe (304) having a second exhaust pipe upstream end (304a) and a second exhaust pipe downstream end (304b); a catalyst device (305) having a catalyst device upstream end (305a) and catalyst device downstream end (305b), wherein the catalyst device upstream end (305a) coupled to the first exhaust pipe downstream end (301b) and the catalyst device downstream end (305b) coupled to the second exhaust pipe upstream end (304a);

a muffler (306) coupled to the second exhaust pipe downstream end (304b); and

an exhaust shield (303) configured to shield the catalyst device (305) and at least a portion of the first exhaust pipe (301), wherein the exhaust shield (303) comprises a plurality of exhaust shield elements (313, 323, ....).

2. The internal combustion engine (8) as claimed in claim 1, wherein the plurality of exhaust shield elements (313, 323, ... ) are manufactured by stamping process.

3. The internal combustion engine (8) as claimed in claim 1, wherein the plurality of exhaust shield elements (313, 323, ... ) are coupled together to form a tubular exhaust shield (303).

4. The internal combustion engine (8) as claimed in claim 1 and claim 3, wherein the plurality of exhaust shield elements (313, 323, ... ) are coupled together along the longitudinal edges to form a tube shaped exhaust shield (303).

5. The internal combustion engine (8) as claimed in claim 1, wherein the first exhaust pipe (301) has a curved portion between the first exhaust pipe upstream end (301a) and the first exhaust pipe downstream end (301b).

6. The internal combustion engine (8) as claimed in claim 1 and claim 5, wherein the first exhaust pipe (301) being a curved profile between the first exhaust pipe upstream end (301a) and the first exhaust pipe downstream end (301b) and the plurality of exhaust shield elements (313, 323, ... ) comprise a curved portion configured to shield the curved portion of the first exhaust pipe (301).

7. The internal combustion engine (8) as claimed in claim 1, wherein the exhaust shield (303) having a variable diameter along the length of the exhaust shield (303).

8. The internal combustion engine (8) as claimed in claim 1, wherein the plurality of exhaust shield elements (313, 323, ... ) are coupled together by means of welding.

9. The internal combustion engine (8) as claimed in claim 1, wherein the exhaust shield (303) comprises of a shield upstream end (303a) and a shield downstream end (303b), wherein the shield upstream end (303a) of the exhaust shield (303) is welded to the outer surface of the first exhaust pipe (301) and the shield downstream end (303b) of the exhaust shield (303) is welded to the second exhaust pipe (304).

10. The internal combustion engine (8) as claimed in claim 1, wherein a substantial gap (310a) maintained between the outer surface of the first exhaust pipe (301) and the inner surface of the exhaust shield (303).

11. The internal combustion engine (8) as claimed in claim 1, wherein a substantial gap (310b) maintained between the outer surface of the catalyst device (305) and the inner surface of the exhaust shield (303).

12. The internal combustion engine (8) as claimed in claim 10 and claim 11, wherein the substantial gap (310a) between the outer surface of the first exhaust pipe (301) and the inner surface of the exhaust shield (303) and the substantial gap (310b) between the outer surface of the catalyst device (305) and the inner surface of the exhaust shield (303) are filled with a heat insulating material.

13. The internal combustion engine (8) as claimed in claim 1, the plurality of exhaust shield elements (313, 323, ....) are semi cylindrical in shape.

14. The internal combustion engine (8) as claimed in claim 1, wherein the internal combustion engine (8) comprises a crankcase (04), a cylinder block (06) coupled to an upper portion of the front end of the crankcase (04) and projecting upwardly and forwardly therefrom.