TECHNICAL FIELD
The present subject matter relates generally to a two-wheeled or three-wheeled vehicle and more particularly to an exhaust emission system for said vehicle.
BACKGROUND
Generally, a two-wheeled vehicle comprises of a frame assembly extending rearwardly from a head tube. The frame assembly acts as a skeleton and a structural member for the vehicle to support its loads. A front wheel is connected to a front portion of the frame assembly through one or more front suspension(s). The frame assembly extends towards a rear portion of the vehicle. A rear wheel is connected to a frame assembly through one or more rear suspension(s).
Moreover, the frame assembly also comprises of a powertrain e.g. an engine assembly coupled to it. The engine assembly is functionally connected to the rear wheel, which provides forward motion to the vehicle. An exhaust emission system is provided for the engine assembly to filter the emission being produced by it. The exhaust emission system further comprises of a muffler assembly provided at a lateral side of the vehicle being mounted to the frame assembly or the vehicle through a mounting bracket. Typically, plurality of panels is mounted to the frame assembly of the vehicle which covers other vehicle parts mounted thereon.
Conventionally, in two-wheeled vehicles, muffler assemblies are provided to dampen noise arising from the engine. The muffler assembly is also provided to control the harmful emissions being emitted into the atmosphere. Specifically, from compact layout & packaging requirements, it becomes essential to have the muffler assembly as small as feasible to contain the width and length of the vehicle. Such requirement contradicts the functional aspects of the muffler to be able to minimize exhaust emissions as well as dampen undesirable noise. Generally, to achieve such objective the already known vehicles implement a heavy and bulky exhaust emission system, a bulkier muffler unit to be precise. However, known systems do not help the purpose and only increase the

weight and manufacturing cost. In addition to it, the system becomes complex which increases the cost of maintaining and makes the serviceability hard.
[0005] Thus, the present subject matter provides an exhaust emission system which is
much lighter, compact and efficient in dampening the sound and improving the emission quality. In addition to it, the present subject matter also improves the sound quality of the exhaust emission system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The detailed description of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.
[0007] Fig. 1 illustrates a side view of an exemplary two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0008] Fig. 2 illustrates a perspective view of the rear portion of the exemplary two-wheeled vehicle as shown in Fig. 1, in accordance with an embodiment of the present subject matter.
[0009] Fig. 3 illustrates a perspective view of an exhaust emission system in accordance with an embodiment of the present subject matter.
[00010] Fig. 4 illustrates a rear view of the exhaust emission system in accordance with an embodiment of the present subject matter.
[00011] Fig. 5 illustrates a sectional view of the exhaust emission system in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[00012] Typically, a two-wheeled or three-wheeled vehicle is operated through an
engine assembly horizontally coupled to the rear end of the frame assembly. Air fuel mixture is supplied to the engine assembly by means of a carburetor. Thereafter,

combustion of the air fuel mixture takes place so that a piston disposed in the engine assembly is set into motion. The piston is operated in a linear motion, after which said liner motion is converted to a rotational motion of a crankshaft, wherein said rotational motion is transferred to the rear wheel finally resulting into motion of the vehicle. This mechanism also results in generation of power and torque by the engine assembly.
[00013] Generally, an exhaust system is provided in an attached condition to the
engine assembly. Typically, the exhaust emission system comprises on an exhaust pipe connected to the internal combustion engine, extending in a downward and rearward direction from said internal combustion engine along a vehicle length direction. The other end of the exhaust pipe is connected to a muffler assembly placed laterally at one side of the vehicle. The unburnt air-fuel mixture in form of exhaust gases is emitted in the atmosphere after a proper oxidation reaction which takes place in the muffler assembly of the exhaust emission system. Typically, the exhaust gases enter the exhaust emission system through the exhaust pipe and later enter the muffler assembly for reaction.
[00014] Conventionally, a baffle assembly is provided in the muffler assembly of the
exhaust emission system to help dampen the noise and provide a better quality of sound. It also helps in reducing the temperature of the exhaust gases present. Typically, the gases pass through a bend pipe of the baffle assembly and are released through the perpetrating holes at its end. After being emitted from the bend pipe it enters a baffle pipe before it is finally emitted in the atmosphere through a tail pipe. This whole process provides a better diffusion of the gases so that the noise is dampened, a better sound quality is provided and the temperature of the gases decreases. In addition to it, the exhaust emission system also adds an extra appeal to the aesthetic and aerodynamics features.
[00015] Over the period of time the exhaust emission systems have evolved to a highly
developed stage right now. The exhaust emission systems which have tried decreasing the temperature of the exhaust gases and enhance the sound quality of the system simultaneously. To achieve these purpose systems have become bulkier and longer so that the volume increases resulting in better diffusion of the gases. This helps in increasing the sound quality and reduces the temperature as well. Generally, in such a

system the tail pipe is provided on the rear at extreme end of the system in a same line of axis as that of the muffler body. There are systems in which the breadth of the muffler assembly is also increased in addition to increase in the length so as to provide that extra volume for diffusion with tail pipe attached at its end.
[00016] However, such known exhaust emission systems with changes implemented to
its length and dimensions face numerous challenges. The length cannot be increased as per desire because in that case the system would become bulkier and disturb the balance of the vehicle and might cross the rear wheel itself. The aerodynamics and the aesthetic appeal of the system also get affected when the length is increased. On some occasions the breadth of the exhaust emission system is increased to provide a large volume for diffusion. But in such cases the banking angle is reduced thus resulting in a lower ground clearance and there is a constant fear of the exhaust emission system hitting the ground at turns. The system mentioned in the prior art above faces a challenge with respect to its manufacturing as well. In order to provide the tail pipe at the rear in the same line as that of the muffler body, a cut needs to be provided on both sides of the system to accommodate the tail pipe there.
[00017] Thus, the present subject matter overcomes the above stated problems of the
exhaust emission system known in the prior art. One of the objectives of the present subject matter is to provide a vehicle employed with an exhaust emission system with better sound quality and reduced temperature of the exhaust gases. Another objective of the present subject matter is to provide an exhaust emission system which tries to achieve the above stated features without making the system bulkier. In an embodiment, yet another objective of the present subject matter is to allow an increased banking angle. In an embodiment, yet another objective of the present subject matter is to provide an exhaust emission system with a better aerodynamically favored shape which is aesthetically appealing too. Yet another aspect being, the present subject matter enables in overall ease of manufacturing that too with reduced manufacturing cost.
[00018] In an embodiment in accordance with the present subject matter, a vehicle
employed with an exhaust emission system is provided. The exhaust emission system

comprises of a muffler assembly attached to the exhaust pipe extending in a downward and rearward fashion from an internal combustion engine. In an embodiment, the muffler assembly as a whole is coupled to a frame assembly of the vehicle.
[00019] In an embodiment, the exhaust pipe emerging from an exhaust port of the
internal combustion engine extends downwardly in a rearward fashion along the length of the vehicle. The exhaust emission system is disposed adjacently to the rear wheel extending substantially along the longitudinal axis of the vehicle. In an embodiment, the muffler assembly provided comprises of a left hand (LH) piece and a right hand (RH) piece welded together to form said muffler assembly. The sides of the muffler assembly converge in at the rearmost portion to meet and form a substantial conical structure. In an embodiment, the converging rear portion of the muffler assembly meet at a point on a longitudinal line of axis passing substantially centrally through the muffler assembly. In an embodiment, at least one of the LH piece and RH piece of the muffler assembly placed in an opposite side of the vehicle protrudes and extends out to provide a larger volume for the system. Thus, it does not disturb the balancing and banking angle of the system, and neither does it makes the system bulky, and provides an extra volume for the muffler assembly as well.
[00020] In an embodiment, the exhaust emission system of the present subject matter
comprises of a U-shaped bend pipe disposed in a muffler unit. The exhaust gases after its reaction with the catalyst converter enters the bend pipe. The bend pipe comprises of perforating holes at it end, from which the toxic gases are released after hitting the end of the bend pipe. In an embodiment the exhaust emission system comprises of a baffle pipe disposed in the muffler unit located just below the upper portion of the bend pipe and is placed substantially parallel to it. The exhaust gases after being emitted from the bend pipe further enter the baffle pipe. In an embodiment, the muffler unit comprises of a locus (P) disposed at its rearmost portion. The locus (P) being disposes in a central portion when seen from a rear view of the vehicle, wherein said locus (P) is located at the point where the rearmost portion converge in to meet, at the partition where the LH and RH side are joined to be precise. Furthermore, in an embodiment the exhaust emission system comprises of a tail pipe disposed at rearmost portion of the muffler assembly in a

sideward fashion offset to the locus (P) disposed at a central position of the muffler assembly when viewed from a rear side of the vehicle. After proper diffusion of the toxic gases in the muffler unit the exhaust gases are emitted through the tail pipe. The sides of the muffler unit converge in at the end and meet at a point on the longitudinal line of axis of the muffler unit to form a conical shape at the rear.
[00021] The present subject matter increases the performance of the exhaust emission
system by improving the sound quality of the system and decreasing the temperature of the exhaust gases. In an embodiment, the present subject matter improves the diffusion rate of the toxic gases by giving optimal amount of time and volume for it. The system is able to achieve this objective without making the exhaust emission system any bulkier or lengthier. In an embodiment, the present subject matter successfully increases the banking angle for the vehicle, resulting in a better ground clearance such that the system does not hit the ground at turns. The tail pipe being located sideward at one side of the muffler unit provides more time and space for the exhaust to travel. Generally, a slot needs to be created on both the LH and RH side to disposes the tail pipe. However, as per the present subject matter manufacturing becomes easier since slot needs to be created only at one of said LH side and RH side.
[00022] The aforesaid and other advantages of the present subject matter would be
described in greater detail in conjunction with the figures in the following description.
[00023] Arrows provided in the top right corner of each figure depicts direction with
respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicated R direction, an arrow Up denotes upward direction, an arrow Dw denoted downward direction, an arrow Rh denotes right side, an arrow Lh denoted left side, as and where applicable.
[00024] Fig. 1 illustrates a left side view of an exemplary scooter type vehicle (10) in
accordance with an embodiment of the present subject matter. The vehicle comprises of a main frame assembly (1) made of carbon fiber and resin material and is conventionally an underbone chassis frame which provides a generally open central area to permit “step-through” mounting by a rider. Typically, the frame assembly (1) comprises of a head tube

(2), a main tube (3), and a pair of side tube LH (4) and side tube RH (only one shown). The head tube (2) is disposed towards the front portion, wherein the main tube (3) extends downwardly and rearwardly from the head tube (2) forming a flat horizontal step-through portion (3S). The other end of the main tube (3) is connected with the pair of side-tubes (LH, RH) through a bracket (not shown).
[00025] The head tube (2) is configured to rotatably support a steering tube (not
shown) and further connected to the front suspension system (6) at the lower end. A handlebar support member (not shown) is connected to an upper end of the steering tube (not shown) and supports a handlebar assembly (9). The upper portion of a front wheel (7) is covered by a front fender (8). The pair of side-tubes (LH, RH) extend from the other end of the main tube (3) being disposed parallel on either side of the vehicle (10) width direction. Each of the said side tube (LH, RH) extends from the main tube (3) in an upward inclined fashion and gradually after a certain length extends rearward in a substantially horizontal and parallel fashion being placed in the vehicle widthwise direction. A plurality of cross pipes (not shown) is secured in between the pair of side-tubes (LH, RH) at selected intervals to support vehicular attachments including a utility box (12), a seat assembly (11) and a fuel tank assembly (not shown). The vehicle furthermore, comprises of a side panel LH and side panel RH which covers the side tubes (LH & RH) and covers the vehicle (10) structure from the sides.
[00026] Generally, the utility box (12) is supported between the side tube LH (4) and
side tube RH so as to be disposed below the seat (11). A fuel tank assembly (not shown) may be disposed on between the rear portions of the pair of the side-tubes (LH, RH). The vehicle (10) further comprises of a rear wheel (13) covered by a rear fender (14) with a tail light (15) disposed above it and a support bar (16) place above the tail light (15) at the end of the seat assembly (11). The rear wheel (13) is supported towards the rear side of the main frame (1) by an internal combustion (IC) engine (5) which is horizontally coupled swingably to the rear of the frame assembly (1) of the two-wheeled vehicle (10) through a rear suspension system (17). The IC engine (5) transfers the drive directly to the rear wheel (13) as it is coupled directly to it through a continuously variable transmission (CVT) system (18). The vehicle further comprises of an exhaust emission

system (shown in Fig, 2) connected to the internal combustion engine (5). The exhaust emission system enables the filtering the exhaust being generated by the internal combustion engine (5), and helps in releasing it in the atmosphere. The present subject matter is applicable for two-wheeled and three-wheeled vehicles. Hence, the word vehicle (10) is interchangeably used which includes the both.
[00027] Fig. 2 illustrates a side view of the rear portion of the exemplary two-wheeled
vehicle (10) as shown in Fig. 1, in accordance with an embodiment of the present subject matter. In an embodiment, the internal combustion engine (5) comprises of a cylinder head (21) which provides a space for combustion of the air-fuel mixture. The cylinder head (21) comprises of an exhaust port (22) to which an exhaust pipe (23) is connected. In an embodiment, the exhaust emission system (20) comprises an exhaust pipe (23) extending in a downward and backward direction along the vehicle length form the exhaust port (22). In an embodiment, the exhaust emission system comprises a muffler assembly (24) connected to the other end of the exhaust pipe (23). The exhaust being produced by the internal combustion engine (5) travels through the exhaust pipe (23) to enter the muffler assembly (24). The muffler assembly (24) helps in oxidization of the emission bring produced by the internal combustion engine (5). In furtherance to it, the muffler assembly also helps in reducing the temperature of the exhaust being produced and dampens the sound of the internal combustion engine (5).
[00028] Fig. 3 illustrates a perspective view of the exhaust emission system (20) in
accordance with an embodiment of the present subject matter. In an embodiment, the muffler assembly (24) is connected at an end of the exhaust pipe (23). As per an embodiment of the present subject matter, the muffler assembly (24) comprises of a front portion (31) formed near the exhaust pipe (23), a central portion (32) and a rear most portion (33) formed near the rear wheel (13) at an extreme end of the vehicle (10). In an embodiment, the muffler assembly (24) comprises of a longitudinal line of axis (XX’) passing substantially through its center. In an embodiment, the front portion (31) of the muffler assembly (24) protrudes outwardly from the exhaust pipe (23) in an oblique fashion when viewed from the rear of the vehicle. Furthermore, the sides of the muffler assembly (24) extend in a substantial parallel manner to form the central portion (32).

Lastly, the sides of the muffler assembly (24) converge in to meet at said longitudinal line of axis XX’ and from the rear most portion (33). The rear most portion (33) is the extreme end of the muffler assembly (23) formed near the rear wheel (13) at the extreme end of the vehicle (10). Through such a construction a sufficient volume is provided for the exhaust to travel and diffuse in the muffler assembly (24). In addition to it, even after increasing the volume of the muffler assembly (24), the structure is compact and not bulky like other known systems.
[00029] Fig. 4 illustrates a rear view of the exhaust emission system (20) of the exemplary two-wheeled vehicle (10) as shown in Fig. 1, in accordance with an embodiment of the present subject matter. In an embodiment, the exhaust emission system (24) comprises of muffler assembly (24), wherein the muffler assembly (24) further comprises of a left hand (LH) piece (41) and a right hand (RH) piece (42) welded together to form said muffler assembly (24). The muffler assembly (24) comprises of a longitudinal line of axis (XX’) passing substantially through its center (as shown in Fig. 3). In one embodiment, the muffler assembly comprises of a tail pipe (43) provided to release the exhaust into the atmosphere after due reaction in the muffler assembly (24). As per an embodiment of the present subject matter, the tail pipe (43) is accommodated on at least one of LH piece (41) and RH piece (42) on an opposite side as that of the vehicle (10). For the purpose of the present subject matter the tail pipe (43) is supposedly accommodated in the RH piece (42) when seen from a rear view of the vehicle (10). In an embodiment, the muffler assembly (24) comprises of a locus (P) disposed on the muffler assembly (24). As per an embodiment of the present subject matter, the locus (P) is disposed at a substantial central position between the LH piece (41) and RH piece (42) when viewed from a rear side of vehicle (10). The locus (P) is disposed centrally with respect to the muffler assembly (24) width as well as height. As per an embodiment of the present subject matter, the tail pipe (43) is accommodated on at least one of the LH piece (41) and RH piece (42) (accommodated in the RH piece for the present subject matter) of the muffler assembly (24) in an offset fashion to the locus (P), such that the tail pipe (43) is offset to the locus (P) by a pre-determined distance α mm. As per an embodiment of the present subject matter, the value of α is not more than 60 mm. The tail pipe (43) is located at a substantial end of the central potion (32) and extends till the rear portion (33)

(shown in Fig 3). In addition to it, the RH piece (42) of the muffler assembly (24) can be seen protruding and expanding outwards in a substantial triangular shape, on a much larger scale as compared to the left hand piece (41). Such a construction is provided to enable the system with sufficient volume for diffusion of gases without making the system bulkier. Thus, the present subject matter provides a sufficient volume without reducing the banking angle. Hence, the exhaust emission system (24), the muffler assembly (24) to be precise does not touches the road at bumpers and turns even after increasing its volume.
[00030] Fig. 5 illustrates a sectional view of the exhaust emission system (20) for the
exemplary two-wheeled vehicle (10) as shown in Fig. 1, in accordance with an embodiment of the present subject matter. In one embodiment, a catalytic converter (51) is proved in the muffler assembly (24), wherein the catalytic converter (51) is connected to an end of the exhaust pipe (23) through a pre-adapter (52) and adapter (53). In one embodiment, a U-shaped bend pipe (54) is attached to the other end of the catalytic converter (51). The U-shaped bend pipe (54) comprises of perforating holes (56) at its end from where the gases are released after passing through it. In an embodiment, the muffler assembly (24) comprises of a baffle pipe (55) through which the toxic gases are passed after being released from the bend pipe (54). This extensive process is provided so that the gases get sufficient volume and time for diffusion resulting in better sound quality and decreased temperature. In an embodiment, the tail pipe (43) is disposed sidewardly at the right hand piece (42) of the muffler assembly (24) which provides the exhaust gases with more time for diffusion. The exhaust after passing through the baffle pipe (56) travels more in the muffler assembly (24) before finding an exit through the tail pipe (43) disposed on the right hand piece (42), offset to locus (P).
[00031] It is to be understood that the aspects of the embodiments are not necessarily
limited to the features described herein. Many modifications and variations of the present subject matter are possible in the light of above disclosure. Therefore, within the scope of claims of the present subject matter, the present disclosure may be practiced other than as specifically described.

We Claim:
1. An exhaust emission system (20) for a vehicle (10) comprising an internal
combustion engine (5), wherein said exhaust emission system (20) comprises:
an exhaust pipe (23) extending downwards from said internal combustion engine
(5) in a rearward direction along vehicle length;
a tail pipe (43) provided for discharge of exhaust from said exhaust emission
system (20); and
a muffler assembly (24) attached on other end of said exhaust pipe (23) comprises
a locus (P) disposed thereto at a substantial central position of said muffler
assembly (24) in a widthwise and vertical direction thereof, when viewed from a
rear side of said vehicle (10), and wherein said tail pipe (43) being disposed at one
side of said muffler assembly (24) substantially offset to said locus (P) of said
muffler assembly (24) by a pre-determined distance.
2. The exhaust emission system (20) as claimed in claim 1, wherein said muffler assembly (24) comprises a left hand (LH) piece (41) and a right hand (RH) piece (42) welded together to form said muffler assembly (24), and wherein said locus (P) is disposed between said LH piece (41) and said RH piece (42) at a substantial central position in a widthwise and height wise direction of said muffler assembly (24) when viewed from a rear side of said vehicle (10)
3. The exhaust emission system (20) as claimed in claim 1 or claim 2, wherein said tail pipe (43) is accommodated in said RH piece (42) when seen from a rear view of said vehicle (10).
4. The exhaust emission system (20) as claimed in claim 1 or claim 2, wherein said tail pipe (43) is disposed on said RH piece (42) offset to said locus (P) by a pre-determined distance of not more than 60mm.

5. The exhaust emission system (20) as claimed in claim 1, wherein said muffler assembly (24) comprises of a front portion (31), a central portion (32), a rear portion (33) and a longitudinal axis XX’ passing through it in a substantial central fashion.
6. The exhaust emission system (20) as claimed in claim 5, wherein said front portion
(31) is formed adjacent to said exhaust pipe (23), and sides of said front portion (31)
protrude out in an oblique fashion from said exhaust pipe (23).
7. The exhaust emission system (20) as claimed in claim 5, wherein said central portion
(32) formed after said front portion (31) comprises of sides extending in a substantial
parallel fashion to each other.
8. The exhaust emission system (20) as claimed in claim 5, wherein said rear portion
(33) formed at a rearmost point comprises of sides converging in to meet at said
longitudinal axis XX’ forming a substantial conical like structure.
9. The exhaust emission system (20) as claimed in claim 2, wherein said RH piece (42) extends and protrudes out in a substantial triangular shape as compared to said LH piece (41) being substantially plain.
10. The exhaust emission system (20) as claimed in claim 1 or claim 2, wherein said tail pipe (43) disposed on said RH piece (42) is located at a substantial end of said central portion (32) extending till said rear portion (33) of said muffler (24).