[0001] The present invention relates to vehicles, and more particularly to an exhaust system of a vehicle.

BACKGROUND

[0002] A vehicle, particularly vehicle configured to be ridden such as motorized scooter, motorcycle, three-wheeled vehicle, and four wheeled vehicle such as all- terrain vehicle, comprise an internal combustion engine and an exhaust emission gas purifying device. The exhaust emission gas purifying device, also referred to as “exhaust gas purifying device” is employed to clean the exhaust gases discharged by the internal combustion engine, during operation thereof. The purified exhaust gases from the exhaust gas purifying device are subsequently discharged into the atmosphere. Generally, a catalyst unit, also referred to as a“catalytic converter” is used as the exhaust gas purifying device. The catalyst unit is disposed either inside the muffler or in the middle of an exhaust pipe having one end thereof connected to the engine and having the other end thereof connected to a muffler.

[0003] Generally, the catalyst unit is provided upstream of the muffler. However, due to stricter emission norms, the catalyst unit needs to be provided closer to the combustion chamber, so that the catalysts contained therein can get activated quickly. Therefore, typically, either the catalyst unit is taken out from the muffler and provided near to the combustion chamber, or an additional catalyst unit is arranged closer to the combustion chamber. Such placement of the catalyst unit tends to improve the gas purification performance of the catalyst unit, resulting in cleaner, more purified exhaust emission. [0004] However, in this arrangement, i.e., when the catalyst is arranged proximate to the combustion chamber, the catalyst unit is positioned below, or in the vicinity of, the engine main body. This increases overall complexity of exhaust layout. Further, during engine operation or when the engine is just stopped after an extended run, there is increase in temperature of the catalyst which may affect the nearby components of the vehicle. Moreover, if the catalyst unit in the exhaust pipe is positioned on the side of the vehicle, there exists higher likelihood of injury because the catalyst unit in the exhaust pipe can come in accidental contact of human body.

SUMMARY OF INVENTION

[0005] In one aspect of the present invention, a vehicle is provided. The vehicle comprises a frame, an internal combustion engine, and an engine mounting system for swingably mounting the internal combustion engine to the frame. The engine mounting system comprising, a right link arm, a left link arm, a pivot shaft, and an engine support member. The vehicle further includes an exhaust system. The exhaust system comprising, an exhaust pipe having a first bent portion, a linear portion, and a second bent portion, the linear portion connects the first bent portion with the second bent portion frame; and an exhaust gas purification device fluidically connected to the exhaust pipe. The exhaust gas purification device is positioned at an angle to a longitudinal direction of the vehicle. The exhaust gas purification device is positioned on the exhaust pipe in a direction substantially along a width direction of the frame, between the first bent portion and the second bent portion. The exhaust gas purification device is positioned above the engine mounting system. In an embodiment, each of the exhaust pipe and the exhaust gas purification device is positioned above the engine mounting system.

[0006] Therefore the present invention provides the vehicle that allows positioning of the exhaust gas purification device proximate to the engine unit and the exhaust port, thereby allowing the temperature of the exhaust gas purification device to quickly reach the activation temperature due to heat from exhaust gases coming out from the exhaust port of the engine unit. In addition, the present invention provides the vehicle having the exhaust gas purification device and the exhaust pipe positioned at a height above the right link arm of the engine mounting system. Owing to such positioning of the exhaust gas purification device and the exhaust pipe, the exhaust gas purification device and the exhaust pipe have considerable clearance from the ground and are above the engine mounting system.

[0007] In an embodiment, the first bent portion of the exhaust pipe is disposed in between the pivot shaft and the engine support member. The upstream end of the first bent portion is connected to an exhaust port of the internal combustion. The exhaust gas purification device of the exhaust pipe includes an upstream end, and a downstream end. Further, the exhaust gas purification device of the exhaust pipe is disposed above the pivot shaft and the engine support member. The exhaust gas purification device is disposed above the engine support member. In particular, the exhaust gas purification device is disposed in a space between the internal combustion engine and the engine mounting system. [0008] Owing to this configuration of the first bent portion and the positioning of the exhaust gas purification device between the engine mounting system, the space between the engine unit and the swing support system is utilized effectively allowing for mounting of exhaust gas purification device to the exhaust pipe without enlarging the overall width of the vehicle, which does not affect the vehicle body design [0009] In an embodiment, the vehicle further includes a muffler device connected to the tail pipe of the exhaust pipe. The muffler device is positioned along longitudinal direction of the vehicle. Further, the exhaust gas purification device, in an embodiment, is a three way catalyst. In an embodiment, the exhaust gas purification device is positioned at a first predetermined height (H2) from a ground surface, and the engine mounting system is positioned at a second predetermined height (Hl) from the ground surface (S). The second predetermined height (H2) is greater than first predetermined height (Hl). Owing to the positioning of the exhaust gas purification device above the engine mounting system, the exhaust gas purification device remains at a suitable ground clearance from the ground surface (S) and therefore remains protected.

[00010] In one aspect of the present invention, a vehicle is provided. The vehicle includes a frame; an engine mounting system; an internal combustion engine swingably mounted to the frame through the engine mounting system; an engine cooling fan unit mounted to the internal combustion engine; and an exhaust system. The exhaust system includes an exhaust pipe comprising a first bent portion, a second bent portion, and a tail pipe, a downstream end of the second bent portion fluidically connected to an upstream end of the tail pipe; a second exhaust gas purification device positioned on a downstream end of the tail pipe; a muffler device connected to the second exhaust gas purification device, wherein the second exhaust gas purification device and the muffler device are positioned along a liner axis (Ll - Ll’) of the tail pipe; and a first exhaust gas purification device connected between the first bent portion and the second bent portion. The second exhaust gas purification device comprises a first end connected to a downstream end of the first bent portion, and a second end connected to an upstream end of the second bent portion. The second end of the first exhaust gas purification device is positioned behind the first end of the first exhaust gas purification device.

[00011] This configuration of the first exhaust gas purification device enables the first exhaust gas purification device to occupy less horizontal length, and accordingly, in this configuration, space between the internal combustion engine and the swing support system can be utilized effectively for mounting exhaust gas purification device to the exhaust pipe without having to enlarge the overall width of the vehicle.

[00012] In an aspect of the invention, a line joining the second end of the first exhaust gas purification device and the first end of the first exhaust gas purification device forms an angle (a) within a range of 3 degree to 15 degree with respect to a horizontal axis (H-TG) along width of the vehicle. In an embodiment, the line (i) joining the second end and the first end of the first exhaust gas purification device forms an angle (a) of 11 degree with respect to the horizontal axis (H-H’) along width of the vehicle.

[00013] Further, the second end of the first exhaust gas purification device is positioned at an offset towards exhaust port of the engine, from a longitudinal axis (L- L’) along an outer peripheral edge of the engine cooling fan unit. Moreover, the second exhaust gas purification device is positioned below the opening of the engine cooling fan unit.

[00014] In this configuration, each of the first exhaust gas purification device and the second exhaust gas purification device, which are generally a very hot portion of the exhaust pipe, are arranged away from the engine cooling fan unit. Therefore, there is very less chance that the engine cooling fan unit will suck hot air around the second exhaust gas purification device, which may affect the cooling of the internal combustion engine.

[00015] In one aspect of the present invention, a vehicle is provided. The vehicle includes a frame; an engine mounting system; an internal combustion engine swingably mounted to the frame through the engine mounting system; an engine cooling fan unit mounted to the internal combustion engine; and an exhaust system. The exhaust system includes an exhaust pipe comprising a first bent portion, a second bent portion, and a tail pipe, a downstream end of the second bent portion fluidically connected to an upstream end of the tail pipe; a second exhaust gas purification device positioned on a downstream end of the tail pipe; a muffler device connected to the second exhaust gas purification device, wherein the second exhaust gas purification device and the muffler device are positioned along a liner axis (Ll - Ll’) of the tail pipe; and a first exhaust gas purification device connected between the first bent portion and the second bent portion. The second exhaust gas purification device comprises a first end connected to a downstream end of the first bent portion, and a second end connected to an upstream end of the second bent portion. The second end of the first exhaust gas purification device is positioned below the first end of the first exhaust gas purification device.

[00016] This configuration of the first exhaust gas purification device enables the first exhaust gas purification device to occupy less horizontal length, and accordingly, in this configuration, space between the internal combustion engine and the swing support system can be utilized effectively for mounting exhaust gas purification device to the exhaust pipe without having to enlarge the overall width of the vehicle.

[00017] In an aspect of the invention, a line (I - G joining the second end of the first exhaust gas purification device and the first end of the first exhaust gas purification device forms an angle (a) within a range of 3 degree to 15 degree with respect to a horizontal axis (H-TG) along width of the vehicle. In an embodiment, the line (I - G) joining the second end and the first end of the first exhaust gas purification device forms an angle (a) of 11 degree with respect to the horizontal axis (H-TT) along width of the vehicle. [00018] Further, the second end of the first exhaust gas purification device is positioned at an offset towards exhaust port of the engine, from a longitudinal axis (L- L’) along an outer peripheral edge of the engine cooling fan unit. Moreover, the second exhaust gas purification device is positioned below the opening of the engine cooling fan unit. The position of the second exhaust gas purification device is proximate to the engine unit, facilitates easy routing of the exhaust pipe, such that there is no likelihood of the exhaust pipe etc. contacting the user and causing burning issues.

[00019] In this configuration, each of the first exhaust gas purification device and the second exhaust gas purification device, which are generally a very hot portion of the exhaust pipe, are arranged away from the engine cooling fan unit. Therefore, there is very less chance that the engine cooling fan unit will suck hot air around either of the first exhaust gas purification device and the second exhaust gas purification device, which may affect the cooling of the internal combustion engine. BRIEF DESCRIPTION OF DRAWINGS

[00020] 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 wherein like reference numerals represent like elements and in which:

[00021] FIG. 1 is a perspective view of an exemplary vehicle, according to an embodiment of the present invention;

[00022] FIG. 2 is a view of a body frame of the vehicle, according to an embodiment of the present invention;

[00023] FIG. 3 is a bottom view of the vehicle, according to an embodiment of the present invention;

[00024] FIG. 4 is a bottom view of the power unit along with exhaust system of the vehicle, according to an embodiment of the present invention; [00025] FIG. 5 is a front view of the power unit along with exhaust system of the vehicle, according to an embodiment of the present invention;

[00026] FIG. 6 is a view of the exhaust system of the vehicle, according to an embodiment of the present invention;

[00027] FIG. 6A is a side view of the exhaust system of the vehicle, according to an embodiment of the present invention;

[00028] FIG. 7 is another view of the exhaust system of the vehicle, according to an embodiment of the present invention;

[00029] FIG. 8A is another view bent portion and linear portion of the exhaust system of the vehicle, according to an embodiment of the present invention; and [00030] FIG. 8B is another view bent portion and linear portion of the exhaust system of the vehicle, according to yet another embodiment of the present invention.

[00031] 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

[00032] 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.

[00033] 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.

[00034] 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. [00035] While the present invention is illustrated in the context of a vehicle, however, exhaust system and aspects and features thereof can be used with other type of vehicles as well. The terms“vehicle”,“two wheeled vehicle” and“motorcycle” have been interchangeably used throughout the description. The term“vehicle” comprises vehicles such as motorcycles, scooters, bicycles, mopeds, scooter type vehicle, all-terrain vehicles (ATV) and the like. [00036] 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. [00037] Referring to Figure. 1, 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. [00038] As illustrated in Figure 2, the vehicle (100) comprises a body frame

(200), a pair of front fork (l2la, l2lb), a front fender (109), a rear fender (111), a front wheel (108), a steering handle bar (107), a fuel tank (not illustrated) provided below the seat (106), a utility box (105), an engine unit (300), an exhaust system (500), an engine cooling fan unit (316), a side body cover (104), a front cover (126), a leg shield (103), a lower front cover (102), a tail light (139), a headlight (123), a foot board (128), a rear suspension (not visible in figures), a rear grip (141), a rear wheel (127).

[00039] As illustrated in Figure 02, the body frame (200), also referred to as “frame (200)” includes a head tube (110), a main frame (112) and a pair of rear seat sub-frames (H4a), (H4b) and one or more cross frames (116), (120), and (124). The main frame (112) extends downward and backward from the head tube (110) and then extends substantially horizontally. The main frame (112) is provided with the cross member (124) which is connected to the rear end of the main frame (112). The cross frame member (124) extends in the cross direction of the vehicle (100). The cross frame member (124) supports the engine unit (300), also referred to as“internal combustion engine (300)”, or simply engine (300)”. A pair of right and left rear seat sub-frames (114a) and (114b) extends rearwardly and upwardly from the ends of the cross member (124) and then approximately horizontally. The rear part of the rear seat sub-frames (114a) and (114b) curves at the rear end and connected by a bracket (not shown in figure). A‘U’ character- like front side crossing frame (120) is constructed over the front part of the rear seat sub-frames (114a) and (114b). The rear side cross frame member (116) is constructed over the substantially middle part of the rear seat sub-frames (114a) and (114b). [00040] A cross pipe (122) is provided by the upper surface of the front part of the approximately horizontal part of the main tube (112), along the cross direction, and the pair of right and left sub-frames (117a) and (117b) extend back from the both- ends side of the cross pipe (122). These left and right sub-frames (117a) and (117b) are extended to back from the front in the state where it is inclined a little in a side view, they are welded on the cross member (124) forming a step floor structure (125).

[00041] A foot board (128), shown in Figure. 1, is disposed above the step floor structure (125). The foot board (128) is disposed between the seat (130) and the head pipe (122). The footboard (128) is positioned lower than the seat (130). The foot board (128) is the component on which the rider puts his/her feet. Further, a first U-shaped frame tube (118a) extends obliquely downward and rearward, the front ends of which is welded to the left rear seat sub-frames (114a) at a position near the front side cross frame (120). Similarly, a second U-shaped frame tube (118b) extends obliquely downward and rearward, the front ends of which are welded to the right sub-frames (H4b) at a position near the front side cross frame (120). The first and second U- shaped frame tubes (118a) and (118b) are used for mounting a foot peg (328).

[00042] With reference to Figure 1 and Figure 2, the head tube (110) is steerably connected to the front fork (121) and a front wheel (108) is attached to a lower end of the front forks (121 a, 121 b). A handlebar (107) is attached to an upper end of the head tube (110). Ahead light (123) is arranged in front of the handlebar (107). A front fender (109) is provided so as to cover an upper portion of the front wheel (108). A seat (106) on which the rider straddles is supported by rear seat sub frames (H4a) and (H4b).

[00043] The leg shield (103) that protects legs of a rider is provided on the front side. A centre frame cover is provided behind the leg shield (103). A tail light (139) and a rear fender (111) are provided at a rear portion of the side frame cover (104). A fuel tank (not illustrated) is arranged under the seat (106) inside the side frame cover (104). The front cover (126) and a lower front cover (102) forms the front cover portion of the vehicle (100). [00044] The fuel tank (not illustrated) is mounted in the space between rear end portion of the rear seat sub-frames (1 l4a, 1 l4b) and the rear side crossing frame (116), as illustrated in Figure 2. The rear side crossing frame (116) has one or more mounting means such as bracket and the like, for mounting the fuel tank. An engine unit (300) is arranged downwardly in front of the fuel tank. [00045] The engine unit (300), as illustrated in the Figure 1 to Figure 6, and

Figure 6A, is a casing which houses a power unit, a transmission unit and a reduction unit. The engine unit (300) is internally partitioned into chambers, as the power unit chamber (202), the transmission chamber (204) and the reduction chamber (210). The power unit chamber (202) and the transmission chamber (204) are disposed side by side and the reduction chamber (210) is disposed rearward of the transmission unit

(204).

[00046] In an embodiment, the engine unit (300) is a single-cylinder, four-stroke- cycle and forced-air-cooling internal combustion engine. The engine unit (300) comprises a crankcase (214), a cylinder block (313) attached to the front end of the crankcase (214), a cylinder head (312) attached to the cylinder block (313), and a head cover (311) for covering a front opening in the cylinder head (312). The power unit (202) is disposed in the vehicle (100) in substantially horizontal position with head cover (311) positioned towards the front wheel of the vehicle (100). In the power unit

~ P ~ (202), the single cylinder air-cooled engine projectingly provided on the body frame (200) is included, and is disposed in a manner that the cylinder axis of the power unit (202) becomes substantially horizontal along the front and rear direction of the vehicle (100). [00047] The crankcase (214) includes a crankshaft (not illustrated) which extends in the left-right direction of the vehicle (100). The crankshaft is connected to a piston. A generator/alternator (not shown in figure) is provided on the right end of the crankshaft. The engine cooling fan unit (316) is mounted to right side of the crankshaft. The engine cooling fan unit (316) includes an outer peripheral edge (316a) and a fan cover having plurality of fins cover the right-side portion of the engine cooling fan. Air in the power unit (202) is sucked into by means of the engine cooling fan unit (316) being driven by the crankshaft. The engine cooling fan unit (316) is adapted to suck air from the outside and throw the air into the power unit (202) to cool the cylinder block (313) and other component in the engine unit (300). [00048] The cylinder head (312) includes an intake port (not visible in figures) and an exhaust port (321). The exhaust port (321) is provided a cylinder head wall which is facing ground in the vehicle layout. The intake port is provided in another wall of the cylinder head opposite to the exhaust port (321). As shown in Figure 5, the engine unit (300) has an air cleaner (317) mounted on the upper surface side of the transmission chamber (204) positioned on the rear side of the vehicle (100), and has a throttle device (323) joined to the front of the above air cleaner (317). An intake pipe (not shown in figure) extends forward from the throttle body (323), and a mixed air is supplied to the engine unit (300) through the above intake pipe.

[00049] The transmission chamber (204) includes a V-belt around a drive pulley, which is mounted to a left end of the crankshaft, and a driven pulley, which is mounted to a driven shaft. The engine unit (300) rotatably supports a rear wheel (127) via the transmission chamber (204) and the reduction chamber (210) on the rear side of the vehicle (100). [00050] As illustrated in Figure 5, the throttle device (323) may be a carburetor or a throttle body. The intake pipe communicates with an intake port in the cylinder head (312), and through an intake passage, the purified air or the air-fuel mixture is supplied to the intake port in the cylinder head (312) from the air cleaner (317) via the throttle device (323).

[00051] Further, as shown in Figures 1, 3 and 4, the engine unit (300) includes an exhaust system (500) comprising an exhaust pipe (301), the muffler device (307), an first exhaust gas purification device (320), an oxygen detector (310). The exhaust pipe (301) is connected to the downstream end of the exhaust port (321). The muffler device (307) is provided with a discharge port (324) which is exposed to the atmosphere. The muffler device (307) is connected to the exhaust pipe (301) and allows the exhaust gas flowing from the downstream end of the exhaust pipe (301) to flow to the discharge port (324). The muffler device (307) is configured to restrain sound generated by the exhaust gas. In an embodiment, the exhaust system (500) further includes a second, an additional exhaust gas purification device such as catalyst. The oxygen detector (310) is provided upstream of the exhaust gas purification device (320a) such as catalyst.

[00052] The engine unit (300) is supported by the body frame (200) in a swingable manner by an engine mounting system (400), also referred to as a swing support system (400). As shown in Figure 3, the swing support system (400) includes a right link arm (133R), a left link arm (133L), a right engine side bracket (134R), and a left engine side bracket (134L).

[00053] The swing support system (400) further includes a pivot shaft (132). In an embodiment the pivot shaft (132) includes two first pivot shafts namely a first pivot shaft (132R) and a first pivot shafts (132L), collectively referred to as first pivot shafts

(132R), (132L) and an engine support member (131) which includes a right engine support means (131R) and a left engine support means (131L). The engine unit (300) and the rear wheel (127) integrally swing about the first pivot shafts (132R) and (132L). A bracket (135R) is fixed to a position in the vicinity of a right end portion of the cross frame member (124). Similarly, a bracket (135L) is fixed to a position in the vicinity of a left end portion of the cross frame member (124). The brackets (135R) and (135L) extend rearward from the cross frame member (124). The right link arm (133R) is swingably connected to the bracket (135R) via the right engine support means (131R).

[00054] The left link arm (133L) is swingably connected to the bracket (135L) via the left engine support means (131L). As such, the right link arm (133R) and the left link arm (133L) are swingably supported by the body frame (200). In an embodiment, the right and left engine support means (131R) and (131L) is left and right end of a single shaft having a bolt at each left and right ends. In an embodiment, the right and left engine support means (131R) and (131L) are separate shaft each of these include a bolt. The first pivot shafts (132R) and (132L) extend in the left-right direction. The first pivot shaft (132R) and the first pivot shaft (132L) are provided to be coaxial. In an embodiment, the first pivot shaft (132R) and the first pivot shaft

(132L) forms a single shaft. The right link arm (133R) and the left link arm (133L) are formed to be symmetrical in the left-right direction.

[00055] As shown in Figure 3, the right engine side bracket (134R) and the left engine side bracket (134L) constitute a part of the engine unit (300). In an embodiment, the right engine side bracket (134R) and the left engine side bracket

(134L) constitute part of the engine unit (300), more specifically, the crankcase (202). The right engine side bracket (134R) is provided at a right end of a lower part of the engine unit (300). The left engine side bracket (134L) is provided at a left end of the lower part of the engine unit (300). The right engine side bracket (134R) and the left engine side bracket (134L) are formed to be substantially symmetrical in the left-right direction.

[00056] The right engine side bracket (134R) and the left engine side bracket (134L) extend frontward. A front end portion of the right engine side bracket (134R) is connected to the right link arm (133R) via a right engine support means (131R). A front end portion of the left engine side bracket (134L) is swingably connected to the left link arm 133L via a left engine support means (131L). As such, the right engine side bracket 134R and the left engine side bracket (134L) are swingably connected to the right link arm (133R) and the left link arm (133L), respectively. Owing to such connections, the engine unit (300) is allowed to swing about the first pivot shafts (132R) and (132L). The right and left engine support means (131R) and (131L) extend in the left- right direction. The right and left engine support means (131R) and (131L) are provided to be coaxial. [00057] In an embodiment, the right and left engine support means (131R) and

(131L) form a single shaft. The right and left engine support means (131R) and (131L) are provided rearward of the first pivot shafts (132R) and (132L). In an embodiment, the right link arm (133R), the left link arm (133L), the first pivot shafts 132R, (132L) and the right and left engine support means (131R), (131L) together forms an integrated unit. The exhaust port (321) lies between the right link arm (133R) and the left link arm (133L) when viewed from the bottom side as shown in Figures 3 and Figure 4. As shown in Figure 3 to Figure 6, the exhaust pipe (301) is connected to the downstream end of the exhaust port (321). The exhaust pipe (301) includes a first bent portion (302), a second bent portion (303), and a tail pipe (330). A linear portion (304) is connected to the second bent portion (303). The exhaust gas purification device

(320) connects the first bent portion (302) and the second bent portion (303). In an embodiment, the exhaust gas purification device (320) is embodied as a linear portion (304) that connects the first bent portion (302) and the second bent portion (303). The upstream end of the first bent portion (302) has a flange (not numbered) communicatively connected to the exhaust port (321). The first bend portion (302) is extended downward and sideward from the exhaust port (321) substantially in the width direction of the vehicle (100). The first bend portion (302) is connected to upstream end of the linear portion (304). The first bent portion (302) of the exhaust pipe (301) is disposed in between the exhaust port (321) and the right and left link arms (133R), (133L), when viewed in up and down direction of the vehicle (100). In an embodiment, both the first bent portion (302) and the exhaust gas purification device (320) of the exhaust pipe (301) may be disposed in between the exhaust port (321) and the right and left link arms (133R), (133L), when viewed in up and down direction of the vehicle (100).

[00058] The linear portion (304) of the exhaust pipe (301) extends substantially in the width direction of the vehicle (100). The second exhaust gas purification device (320) is provided in the linear portion (304) of the exhaust pipe (301). In an embodiment, the second exhaust gas purification device (320) is embodied as the linear portion (304) of the exhaust pipe (301). As shown in Figure. 3, the first bent portion (302) of the exhaust pipe (301) is disposed in between the first pivot shafts (132R), (132L) and the right and left engine support means (131R), (131L), when viewed in frontward and rearward direction of the vehicle (100). In an embodiment, the first bent portion (302) and exhaust gas purification device (320) of the exhaust pipe (301) disposed in between the first pivot shafts (132R), (132L) and the right and left engine support means (131R), (131L), when viewed in frontward and rearward direction of the vehicle (100). The exhaust gas purification device (320) of the exhaust pipe (301) extends at an angle to a longitudinal direction of the vehicle (100). In an embodiment, the exhaust gas purification device (320) of the exhaust pipe (301) extends substantially in the width direction of the vehicle (100).

[00059] The upstream end of the second bend portion (303) is connected to the downstream end of the exhaust gas purification device (320). Further, the upstream end of the second bend (303) extends in the rearward direction while bending such that the downstream end of the tail pipe (330) is connected to the muffler device (307). The muffler device (307) is arranged in its longitudinal direction almost along a forward and rearward direction of the vehicle (100). As illustrated, the second exhaust gas purification device (320a) and the muffler device (307) are positioned along a liner axis (Ll - Ll’) of the tail pipe (330). [00060] In an embodiment, each of the first exhaust gas purification device (320), and the second exhaust gas purification device (320a) may be catalytic converters. In an example, each of the first exhaust gas purification device (320), and the second exhaust gas purification device (320a) may be a three-way catalyst. The three way catalyst may be a honeycomb structure or any other suitable structure for catalyst having a coatings of metal such as platinum, palladium, rhodium and the like metal combination thereof. These configuration, by way of example, not limited to this, may be in other configurations.

[00061] As shown in Figure 5, the second exhaust gas purification device (320) of the exhaust pipe (30) is in fluidic communication with the exhaust gases discharge from the exhaust port (321). In an embodiment, the first bent portion (302) is formed by joining two half shell structure at the respective peripheral ends to form a hollow pipe structure having substantially uniform diameter. In an embodiment, the first bent portion (302) is a hollow pipe structure communicatively connected to the exhaust port (321) at one end.

[00062] Also, the exhaust purification device (320) is fluidically connected to the first bent portion (302). In an embodiment, as shown in Figure 8 B, the linear portion (304) is constituted by a holder (326) and a pair of cones (305), (306). The exhaust gas purification device (320) is provided in the holder (326). The pair of cones (305), (306) includes an upstream cone (305) and a downstream cone (306).

[00063] The downstream end of the first bent portion (302) is connected to the holder (326) via the upstream cone (305). Further, the upstream end of the second bent portion (303) is connected to the holder (326) via the downstream cone (306). The exhaust gas discharge from the exhaust port (321) passes through the first bent portion (302), the linear portion (304) and the third bent portion (303) to reach the muffler device (307) and finally exit into the atmosphere from the exit end (324) of the muffler device (307). [00064] In an embodiment, as shown in Figure 8 A, the linear portion (304) is a hollow pipe (327) and the exhaust gas purification device (320) is provided in the hollow pipe (327). The exhaust purification device (320) is provided in the hollow pipe (327) that constitutes the linear portion (304), and between the first bent portion (302) and the second bent portion (303) of the exhaust pipe (301).

[00065] As shown in Figure 7, the distance between the longitudinal axis YY’ of the oxygen detector (310) and the central axis XX’ of the upstream end of the first bent portion (302) is smaller than the distance between the longitudinal axis YY’ of the oxygen detector (310) and the upstream edge of the exhaust gas purification device (320). In this configuration, both the oxygen detector (310) and the exhaust gas purification device (320) can be arranged very compactly within first bent portion (302) and the linear portion (304) in the width direction of the vehicle (100).

[00066] Further, as shown in Figure 5, the oxygen detector (310) overlaps with the exhaust gas purification device (320) when viewed along the downstream end of the linear portion (304) of the exhaust pipe (301). Also, the emission can be controlled easily as the activation temperature of the oxygen detector (310) and the exhaust gas purification device (320) can be reached very quickly due to their proximity with the exhaust port (321).

[00067] As shown in Figure 5, the exhaust gas purification device (320) of the exhaust pipe (301) is arranged in such a way that the rear end of the second exhaust gas purification device (320) at the downstream end of the linear portion (304) is substantially within the outer boundary of the engine cooling fan unit (316) when viewed from the front side of the engine unit (300). Further, the second exhaust gas purification device (320) comprises a first end (305a) connected to a downstream end of the first bent portion (302), and a second end (306a) connected to an upstream end of the second bent portion (303). In this configuration, the exhaust gas purification device (320) which is generally a very hot portion of the exhaust pipe (301), is arranged away from the engine cooling fan unit (318). Therefore, there is very less chance that the engine cooling fan unit (318) will suck hot air around the exhaust gas purification device (320) which may affect the cooling of engine unit (300). Further, as shown in Figures 3 and 4, at least a portion of the exhaust gas purification device (320) is arranged between the exhaust port (321) and one of the right link arm (133R) and left link arm (133L) when viewed from bottom side of the vehicle (100).

[00068] In an embodiment, at least a portion of the exhaust gas purification device (320) overlaps with one of the right link arm (133R) and left link arm (133L) when viewed from bottom side of the vehicle (100). In this arrangement, the exhaust gas purification device (320) is arranged in the vicinity of the engine unit (300) and is more close to the exhaust port (321), therefore, temperature of the exhaust gas purification device (320) can easily reach the activation temperature due to heat from exhaust gases coming out from the exhaust port (321) of the engine unit (300), for example, even in the cold state immediately after the start of travel, the exhaust gas mixture gets heated to a relatively short time to activate the exhaust gas purification device (320) quickly.

[00069] As illustrated in Figure 6A, the exhaust gas purification device (320) is disposed at a position higher than, or above, the swing support system (400). The exhaust gas purification device (320) is disposed at a position higher than, or above the right link arm (133R) of the swing support system (400). Alternatively, the exhaust gas purification device (320) may be disposed at a position higher than, or above the left link arm (133L) of the swing support system (400), without deviating from the spirit of the present disclosure.

[00070] Specifically, the exhaust gas purification device (320) is positioned behind the first end (305a) of the first exhaust gas purification device (320). In an embodiment, the second end (306a) of the first exhaust gas purification device (320) is at a height H2 from a ground surface (S), whereas the swing support system (400) is positioned at a height Hl from the first end (305a) of the first ground surface (S), wherein H2 is greater than Hl. In other words, the exhaust gas purification device (320). This inclined configuration of the first exhaust gas purification device (320) enables the first exhaust gas purification device (320) to occupy less horizontal length, accordingly, in this configuration, space between the engine unit (300) and the swing support system (400) can be utilized effectively for mounting exhaust gas purification device (320) to the exhaust pipe (301) without having to enlarge the overall width of the vehicle (100).

[00071] As shown in Figure, 4, a line (i) joining the second end (306a) of the first exhaust gas purification device (320) and the first end (305a) of the first exhaust gas purification device (320) forms an angle (a) within a range of 3 degree to 15 degree with respect to a horizontal axis (H-H’) along width of the vehicle (100). In an embodiment, the line (i) joining the second end (306a) of the first exhaust gas purification device (320) and the first end (305a) of the first exhaust gas purification device (320) forms an angle (a) of 11 degree respect to a horizontal axis (H-H’) along width of the vehicle (100). [00072] During operation of the vehicle (100), when the power unit (202) starts, exhaust gases are discharged from the exhaust pipe (301) from the combustion chamber in the cylinder head (312) via the exhaust port (321). The exhaust gases pass through the inside of the first bent portion (302) of the exhaust pipe (301) to flow into the second exhaust gas purification device (320) provided on the exhaust pipe (301). The second exhaust gas purification device (320) of the exhaust pipe (301) is heated by the exhaust gases and thereby early activation is achieved, and the exhaust gases further pass through the second bent portion (303) of the exhaust pipe (301) and the muffler device (307) to be discharged from exit (324) of the muffler device (307) into the atmosphere. [00073] As the second exhaust gas purification device (320) is arranged in the vicinity of the engine unit (300) and more close to the exhaust port (321), therefore, temperature of the second exhaust gas purification device (320) can easily reach the activation temperature due to heat from exhaust gases coming out from the exhaust port (321) of the engine unit (300), for example, even in the cold state immediately after the start of travel, the exhaust gas mixture was heated to a relatively short time to activate the second exhaust gas purification device (320) quickly.

[00074] The second end (306a) of the first exhaust gas purification device (320) is positioned at an offset towards exhaust port of the engine, from a longitudinal axis

(L- L’) along the outer peripheral edge (316a) of the engine cooling fan unit (316). Moreover, the second exhaust gas purification device (320a) is positioned below the opening of the engine cooling fan unit (316). Therefore, as the second exhaust gas purification device (320) is arranged away from the engine cooling fan unit (316), there is very less chance that the engine cooling fan unit (316) will suck hot air around the second exhaust gas purification device (320) which may affect the cooling of engine unit (300). In particular, at least a portion of the exhaust gas purification device (320) is positioned below a cylinder block (313) of the internal combustion engine (300). [00075] In addition, the position of the second exhaust gas purification device

(320a) is proximate to the engine unit (300), and the muffler device (307) being connected to the tail pipe (330) of the exhaust pipe (301), facilitate easy routing of the exhaust pipe (301), such that there is no likelihood of the exhaust pipe (301) etc. contacting the user and causing burning issues. [00076] Furthermore, in this configuration, space between the engine unit (300) and the swing support system (400) can be utilized effectively for mounting exhaust gas purification device (320) to the exhaust pipe (301) without enlarging the overall width of the vehicle (100), which does not affect the vehicle body design.

[00077] In addition, the exhaust gas purification device (320) is arranged immediately below the engine unit (300) and substantially in the middle of the vehicle (100) therefore lowering gravity center position, thus optimizing the weight balance of the vehicle (300). [00078] In light of the foregoing, the present invention provides the vehicle (100) that allows positioning of the exhaust gas purification device (320) proximate to the engine unit (300) and the exhaust port (321), thereby allowing the temperature of the exhaust gas purification device (320) to quickly reach the activation temperature due to heat from exhaust gases coming out from the exhaust port (321) of the engine unit

(300). In addition, the present invention provides the vehicle (100) having the exhaust gas purification device (320) and the exhaust pipe (301) positioned at a height above the engine mounting system (400). Owing to such positioning of the exhaust gas purification device (320) and the exhaust pipe (301), the exhaust gas purification device (320) and the exhaust pipe (301) have considerable clearance from the ground and are above each of the right link arm (133R) and the left link arm (133L). In particular, each of the first bent portion (302) and the linear portion (304) of the exhaust pipe (301) are disposed in between the first pivot shafts (132R), (132L) and the right and left engine support means (131R), (131L), while the each of the first bent portion (302) and the linear portion (304) of the exhaust pipe (301) are disposed at an height

[00079] 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.

[00080] 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.