Claims:WE CLAIM:
1. A vehicle (100) comprising:
an internal combustion engine (138);
a crankcase (140) extending from the internal combustion engine (138) in a vehicle rear direction, the crankcase (140) partitioned into a right crankcase (140a) extending in a vehicle right direction and a left crankcase extending in a vehicle left direction;
a radiator unit (144) configured for cooling the internal combustion engine (138), the radiator unit (144) extending in a front-rear direction of the vehicle (100) and disposed adjacent to the right crankcase (140a);
an exhaust emission control assembly (146) having a first catalytic convertor (158) for oxidation and reduction of exhaust gases received from the internal combustion engine (138), the first catalytic convertor (158) being provided between the right crankcase (140a) and the radiator unit (144).

2. The vehicle (100) as claimed in claim 1, wherein the exhaust emission control assembly (146) comprises:
an exhaust pipe (154) having a first end (154a) and a second end (154b), the first end (154a) being connected to the internal combustion engine (138);
a muffler unit (156) having a muffler pipe (156a) operably connected to the second end (154b) of the exhaust pipe (154); and
a second catalytic convertor disposed inside the muffler unit (156).

3. The vehicle (100) as claimed in claim 2, wherein the exhaust pipe (154) extends from the first end (154a) to define a first portion (160) extending between a first bend (162) and a second bend (164) of the exhaust pipe (154) in the right direction of the vehicle (100) and a second portion (166) extending between the second bend (164) and the second end (154b) of the exhaust pipe (154) in the rear direction of the vehicle (100).

4. The vehicle (100) as claimed in claim 3, wherein the first catalytic convertor (158) is provided adjacent the second bend (164) of the exhaust pipe (154) such that the first catalytic convertor (158) extends in the rear direction of the vehicle (100) between the second bend (164) and the second end (154b) of the exhaust pipe (154).

5. The vehicle (100) as claimed in claim 1, wherein the first catalytic convertor (158) is provided below a cowl (168) in a side view of the vehicle (100).

6. The vehicle (100) as claimed in claim 1, wherein the right crankcase (140a) comprises a cooling fan to cool the radiator unit (144)

7. The vehicle (100) as claimed in claim 1, wherein the first catalytic convertor (158) extends in a front-rear or longitudinal direction of the vehicle (100).

8. The vehicle (100) as claimed in claim 1, wherein the radiator unit (144) and the first catalytic convertor (158) partially overlaps each other in a side view of the vehicle (100).

Dated this 02nd day of March 2022
TVS MOTOR COMPANY LIMITED
By their Agent & Attorney

(Nikhil Ranjan)
of Khaitan & Co
Reg No IN/PA-1471 , Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]

TITLE OF INVENTION
A VEHICLE

APPLICANT
TVS MOTOR COMPANY LIMITED, an Indian company, having its address at “Chaitanya”, No.12 Khader Nawaz Khan Road, Nungambakkam, Chennai 600 006, Tamil Nadu, India.

PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present invention relates to a vehicle. More particularly, the present invention relates to placement of a catalytic convertor in the vehicle.

BACKGROUND OF THE INVENTION
[002] A catalytic converter is a device used to reduce the emissions from an internal combustion engine (used in most modern-day automobiles and vehicles). Not enough oxygen is available to oxidize the carbon fuel in these engines completely into carbon dioxide and water, thus toxic by-products are produced. Catalytic converters are used in exhaust systems to provide a site for the oxidation and reduction of toxic by-products (like nitrogen oxides, carbon monoxide, and hydrocarbons) of fuel into less hazardous substances such as carbon dioxide, water vapor, and nitrogen gas.
[003] Due to stringent emission norms, light off temperature of catalytic convertors plays a vital role in the overall emission from the engine. The temperature at which catalytic reactions are initiated within a catalytic converter is light off temperature of catalytic convertor. The time in which catalytic reactions are initiated within a catalytic converter is light off time of catalytic convertor. In order to decrease a light off time of the catalytic convertor, the catalytic converter need to be located as close to the exhaust port as possible to take advantage of the hot exhaust gases. The activation time of the catalytic convertor plays a vital role in emission reduction.
[004] In some vehicle such as scooters, cooling system parts such as a radiator unit and a cooling fan driven by a crank shaft are placed on right hand side of the vehicle. In such vehicles, placement of catalytic convertor close to an exhaust port and also having interface clearances with cooling system parts to achieve a target ground clearance can be difficult. In some prior arts, a catalytic convertor is placed directly below the radiator assembly. This results in decreased ground clearance, i.e., chances of catalytic convertor being damaged due to proximity with the road increases. Thus, such catalytic convertor requires frequent replacement and servicing. Also, since the catalytic convertor is placed directly below the radiator, the temperature of the catalytic convertor increases due to heat emitted from the radiator directly onto the catalytic convertor. This negatively affects the working of the catalytic convertor.
[005] In view of the foregoing, there is a need-felt to overcome the above-mentioned disadvantages.

SUMMARY OF THE INVENTION
[006] In one aspect, a vehicle having an exhaust emission control assembly is disclosed. The vehicle comprises an internal combustion engine and a crankcase extending from the internal combustion engine in a vehicle rear direction. The crankcase is partitioned into a right crankcase and a left crankcase. The right crankcase extends in a vehicle right direction and the left crankcase extends in a vehicle left direction. The vehicle further comprises a radiator unit configured for cooling the internal combustion engine. The radiator unit extends in a front-rear or longitudinal direction of the vehicle and is disposed adjacent to the right crankcase. The vehicle further comprises an exhaust emission control assembly having a first catalytic convertor for oxidation and reduction of exhaust gases received from the internal combustion engine. The first catalytic convertor is provided between the right crankcase and the radiator unit.
[007] In an embodiment, the exhaust emission control assembly comprises an exhaust pipe and a muffler unit. The exhaust pipe has a first end and a second end. The first end of the exhaust pipe is connected to the internal combustion engine. The muffler unit comprises a muffler pipe. The muffler pipe is operably connected to the second end of the exhaust pipe. The exhaust emission control assembly may further comprise a second catalytic convertor disposed inside the muffler unit.
[008] In an embodiment, the exhaust pipe extends from the first end to define a first portion extending between a first bend and a second bend in the right direction of the vehicle and a second portion extending between the second bend and the muffler pipe in the rear direction of the vehicle.
[009] In an embodiment, the first catalytic convertor is provided adjacent the second bend of the exhaust pipe such that the first catalytic convertor extends in the rear direction of the vehicle between the second bend and the muffler pipe.
[010] In an embodiment, the first catalytic convertor is provided inside the exhaust pipe.
[011] In an embodiment, the first catalytic convertor is provided between the muffler pipe and the exhaust pipe.
[012] In an embodiment, the right crankcase comprises a cooling fan to cool the radiator unit.
[013] In an embodiment, the first catalytic convertor extends in front-rear or longitudinal direction of the vehicle.
[014] In an embodiment, the radiator unit and the first catalytic convertor partially overlaps each other in a side view of the vehicle.
[015] In an embodiment, the first catalytic convertor is provided below a cowl in a side view of the vehicle. The cowl is a fan cover or a fan shroud which is used to protect the cooling fan in the crankcase.

BRIEF DESCRIPTION OF THE DRAWINGS
[016] Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 illustrates a right-side view of a vehicle 100, in accordance with an embodiment of the present invention. As an example, the vehicle 100 is a scooter type vehicle.
Figure 2 illustrates a right-side view of a frame structure of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 3 is a top-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 4 is a partial top-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 5 is a bottom-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 6 is a side-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 7 and Figure 8 are perspective views of the exhaust emission control assembly 146 of the vehicle 100, in accordance with an embodiment of the present invention.
Figure 9 illustrates the air flow over the first catalytic convertor 158, in accordance with an embodiment of the present invention.
Figure 10 illustrates comparison of ground clearance with respect to location of the first catalytic convertor, in accordance with an embodiment of the present invention.
Figure 11 illustrates a Bar graph plotting inlet temperature of the radiator unit in accordance with prior art and inlet temperature of radiator unit 144 in accordance with an embodiment of the present invention.
Figure 12 illustrates a Bar graph plotting inlet temperature of the radiator unit in accordance with prior art and inlet temperature of radiator unit 144 in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION
[017] Various features and embodiments of the present invention here will be discernible from the following further description thereof, set out hereunder.
[018] Figure 1 illustrates a right-side view of a vehicle 100, in accordance with an embodiment of the present invention. As an example, the vehicle 100 is a scooter type vehicle. However, this example should not be construed as limiting and is applicable to vehicles having similar construction. The vehicle 100 includes a vehicle body frame 102, a front fork 104, a front wheel 106, a seat 108, a vehicle body cover 110, a fuel tank (not shown), an engine 138 (Refer Figure 2), and a rear wheel 114.
[019] It is to be noted that terms “upper”, “lower”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom” and like terms are used herein based on the illustrated state or in a standing state of the two-wheeled vehicle with a driver sitting thereon unless otherwise elaborated. Furthermore, a longitudinal axis refers to a front to rear axis relative to the two-wheeled vehicle, defining a vehicle longitudinal direction; while a lateral axis refers to a side to side, or left to right axis relative to said vehicle, defining a vehicle lateral direction. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
[020] Arrows provided in the top right corner of figures depicts direction with respect to the two-wheeled vehicle, wherein an arrow F denotes front direction, an arrow R indicates rearward direction, an arrow Up denotes upward direction, an arrow Dw denoted downward direction, an arrow Rt denotes right direction and arrow Lt denotes left direction, as and where applicable.
[021] The vehicle body frame 102 includes a head pipe 118 and a down frame 120. The front fork 104 is turnably supported by the head pipe 118. In an upper portion of the head pipe 118, a handlebar 122 is rotatably integrally connected to a steering shaft (not shown). The handlebar 122 is used to steer the vehicle 100 and is connected to the front wheel 106 through the front fork. The front wheel 106 is rotatably supported by the lower portion of the front fork 104. The down frame 120 extends downwardly from the head pipe 118.
[022] The vehicle body frame 102 includes a first lower frame 124, a second lower frame 126 (refer to Figure 3), a first rear frame 128, and a second rear frame (not shown).
[023] The first lower frame 124 and the second lower frame 126 are connected to the lower portion of the down frame 120, and extend rearwardly therefrom. The first lower frame 124 obliquely tilts upward in the rear direction of the vehicle 100. The second lower frame 126 obliquely tilts upward in the rear direction of the vehicle 100. The first lower frame 124 and the second lower frame 126 are disposed apart from each other in the width/lateral direction (left-right direction) of the vehicle 100. In the present embodiment, the first lower frame 124 is the right side one of the lower frames, whereas the second lower frame 126 is the left side one of the lower frames.
[024] The first rear frame 128 is connected to the rear portion of the first lower frame 124, and extends therefrom obliquely upward in the rear direction of the vehicle 100. The second rear frame (not shown) is connected to the rear portion of the second lower frame 126, and extends therefrom obliquely upward to the rear direction of the vehicle 100. In the present embodiment, the first rear frame 128 is the right side one of the rear frames, whereas the second rear frame (not shown) is the left side one of the rear frames.
[025] The seat 108 is supported by the vehicle body frame 102. The seat 108 is disposed over the first rear frame 128 and the second rear frame (not shown). The vehicle body cover 110 is supported by the vehicle body frame 102. The vehicle body cover 110 includes a front cover 130, a lower cover 132, and a rear cover 134. The front cover covers the head pipe 118 and the down frame 120. The lower cover 132 covers the first lower frame 124 and the second lower frame 126. The lower cover 132 includes a flat footboard 136. As shown, the engine such as an internal combustion engine 138 is disposed rearward of the flat footboard 136 and a fuel tank (not shown) disposed under the flat footboard 136. The internal combustion engine 138 is preferably of a so-called unit-swing type, and is pivotably supported by the vehicle body frame 102. The internal combustion engine 138 is located below the seat 108. The internal combustion engine 138 is preferably a liquid cooled engine. The internal combustion engine 138 is disposed between the first rear frame 128 and the second rear frame (not shown), and partially protrudes forward in a vehicle front direction from the first rear frame 128 and the second rear frame (not shown).
[026] A crankcase 140 extends from the internal combustion engine 138 in the vehicle rear direction and is partitioned into a right crankcase 140a extending in vehicle right direction and a left crankcase (not shown) extending in vehicle left direction. The crankcase 140 accommodates a crankshaft (not shown). The rotational axis of the crankshaft extends in the vehicle width/lateral direction (right-left direction). A transmission assembly (not shown) is disposed in the left crankcase (not shown) whereas the cooling fan (not shown) is disposed in the right crankcase 140a. The transmission assembly is provided for transferring the drive force from the internal combustion engine onto a rear wheel 114 for driving the vehicle 100.
[027] A radiator unit 144 (shown in Figure 2) configured for cooling the internal combustion engine 138 is also provided. The radiator unit 144 extends in the vehicle front-rear/longitudinal direction and is disposed adjacent to the right crankcase 140a. The internal combustion engine 138 is cooled by circulating a liquid called engine coolant through an engine block (not shown) and a cylinder head (not shown) where the internal combustion engine 138 is heated, then through the radiator unit 144 wherein the engine coolant loses heat to the atmosphere, and then returned to the internal combustion engine 138. The engine coolant is usually water-based but may also be oil. It is common to employ a water pump to force the engine coolant to circulate. The cooling fan is used to draw cool air through the radiator unit 144.
[028] An exhaust emission control assembly 146 is provided which is discussed in detail in subsequent Figures. A headlight 148 and instrument cluster [not shown] are arranged on an upper portion of the head pipe 118. A rear suspension (not shown) is provided to the rear wheel for dampening the vibrations induced during travel of the vehicle 100 over undulations on the road surface. A taillight unit 150 is disposed at the end of the vehicle 100 and at rear of the seat 108. A grab rail 152 is also provided for facilitating the grip and/or balance of a pillion rider on the vehicle 100 during movement. The rear wheel 114 is arranged below the seat 108.
[029] Figure 2 illustrates a right-side view of a frame structure of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
[030] As shown, the exhaust emission control assembly 146 comprises an exhaust pipe 154 and a muffler unit 156. As already known in the art, the internal combustion engine 138 comprises an intake port (not shown) and an exhaust port (not shown). The exhaust pipe comprises a first end 154a (Refer Figure 7) and a second end 154b (Refer Figure 7). The first end 154a of the exhaust pipe 154 is operably connected to the exhaust port (not shown) of the internal combustion engine 138. The muffler unit 156 is disposed rearward or in the rear direction of the internal combustion engine 138. The muffler unit 156 is disposed such that it overlaps with the rear wheel 114 in the right-side view of the vehicle 100. The muffler unit 156 comprises a muffler pipe 156a. The second end 154b of the exhaust pipe 154 is operably connected to the muffler pipe 156a. The exhaust emission control assembly 146 comprises at least a first catalytic convertor 158 and a second catalytic convertor (not shown). In one non-limiting example, the second catalytic convertor is disposed in the muffler unit 156.
[031] The exhaust pipe 154 extends from the first end 154a (Refer Figure 7) to define a first portion 160 (Refer Figure 7) which extends in the right direction of the vehicle between a first bend 162 (Refer Figure 7) and a second bend 164 (Refer Figure 7). The exhaust pipe 154 further defines a second portion 166 (Refer Figure 7) which extends from the first portion 160. The second portion 160 is provided between the second bend 164 and the second end 154b of the exhaust pipe 154. The second portion 166 of the exhaust pipe 154 extends in the rear direction of the vehicle 100. The first catalytic convertor 154 is disposed adjacent the second bend 164 such that the first catalytic convertor extends in the rear direction of the vehicle between the second bend 164 and the second end 154b. As shown, the first catalytic convertor 158 and the radiator unit 144 partially overlaps each other in side-view of the vehicle 100.
[032] Figure 3 is a top-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention. Figure 4 is a partial top-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention. Figure 5 is a bottom-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention
[033] As shown in Figure 3, Figure 4 and Figure 5, the first catalytic convertor 158 is provided between the radiator unit 144 and the right-crank case 140a of the vehicle 100. Also, the first catalytic convertor 158 is provided below a cowl 168 (when viewed in side-view of the vehicle 100). The cowl 168 is a fan cover or a fan shroud which is used to protect the cooling fan (not shown) in the right crankcase 140a. Also, exhaust pipe 154 extends from the first end 154a to define the first portion 160 (Refer Figure 7) extending between the first bend 162 (Refer Figure 7) and the second bend 164 (Refer Figure 7). The first portion 160 extends in the right direction of the vehicle 100. Further, the exhaust pipe 154 comprises a second portion 166 (Refer Figure 7) extending between the second bend 164 and the second end 154b of the exhaust pipe 154 in the rear direction of the vehicle 100. The first catalytic convertor 158 is provided adjacent the second bend 164 such that the first catalytic convertor 158 extends in the rear direction or longitudinal direction of the vehicle.
[034] Figure 6 is a side-view of the vehicle 100 illustrating arrangement of the first catalytic convertor 158, in accordance with an embodiment of the present invention.
[035] As shown, the radiator unit 144 and the first catalytic convertor 158 partially overlaps each other. Also, exhaust pipe 154 extends from the first end 154a (Refer Figure 7) to define the first portion 160 (Refer Figure 7) extending between the first bend 162 (Refer Figure 7) and the second bend 164 (Refer Figure 7). The first portion 160 extends in the right direction of the vehicle 100. Further, the exhaust pipe 154 comprises a second portion 166 (Refer Figure 7) extending between the second bend 164 and the second end 154b (Refer Figure 7) of the exhaust pipe 154 in the rear or longitudinal direction of the vehicle 100. The first catalytic convertor 158 is provided adjacent the second bend 164 such that the first catalytic convertor 158 extends in rear direction/longitudinal of the vehicle 100.
[036] Figure 7 and Figure 8 are perspective views of the exhaust emission control assembly 146 of the vehicle 100, in accordance with an embodiment of the present invention.
[037] As shown, the exhaust emission control assembly 146 comprises the exhaust pipe 154 and the muffler unit 156. The exhaust pipe 154 comprises a first end 154a and a second end 154b. The first end 154a of the exhaust pipe 154 is operably connected to the exhaust port (not shown) of the internal combustion engine 138. The muffler unit 156 is disposed rearward of the internal combustion engine 138. The muffler unit 156 is disposed in the vehicle 100 such that it overlaps with the rear wheel 114 in the right-side view of the vehicle 100. The muffler unit comprises a muffler pipe 156a. The second end 154b of the exhaust pipe 154 is operably connected to the muffler pipe 156a. The exhaust emission control assembly 146 comprises at least a first catalytic convertor 158 and a second catalytic convertor (not shown). In one-non limiting example, the second catalytic convertor is disposed in the muffler unit 156.
[038] The exhaust pipe 154 extends from the first end 154a to define a first portion 160 which extends in the right direction/lateral direction of the vehicle 100 between the first bend 162 and the second bend 164. The exhaust pipe 154 further defines the second portion 166 which extends from the first portion 160. The second portion 166 is provided between the second bend 164 and the second end 154b of the exhaust pipe 154. The second portion 166 of the exhaust pipe 154 extends in rear direction/longitudinal direction of the vehicle 100. The first catalytic convertor 158 is disposed adjacent the second bend 164 such that the first catalytic convertor 158 extends in the rear direction/longitudinal direction of the vehicle 100 between the second bend 164 and the second end 154b of the exhaust pipe 154. As shown in Figure 8, the catalytic convertor is provided with a cover 170 to protect the first catalytic convertor 158 from damage.
[039] Figure 9 illustrates the air flow over the first catalytic convertor 158, in accordance with an embodiment of the present invention.
[040] As the catalytic convertor extends in front-rear/longitudinal direction of the vehicle 100, only an end (represented by reference symbol A) of the catalytic convertor 158 facing the down frame 120 is exposed to the air. The natural air flow over the first catalytic convertor 158 is, therefore, low due to less area of contact with air. In other words, the length of the first catalytic convertor 158 is not exposed to the natural air flow and thereby heat retention in the first catalytic convertor 158 is improved. This results in fast activation of the first catalytic convertor 158, thereby improving the efficiency of the first catalytic convertor 158.
[041] Figure 10 illustrates comparison of ground clearance with respect to location of the first catalytic convertor, in accordance with an embodiment of the present invention.
[042] As shown, the line G-G depicts a ground line. The line C1 depicts the ground clearance from the ground line G-G when a catalytic convertor is provided directly below the radiator unit 144 in accordance with the prior art. The line C2 depicts the ground clearance from the ground line G-G when the first catalytic convertor 158 is provided between the radiator unit 144 and right crankcase 140a in accordance with the present invention. It can be clearly seen that ground clearance for the present invention is increased by a value C1-C2. In other words, the present invention provides an improved ground clearance with respect to the prior art.
[043] Figure 11 illustrates a Bar graph plotting ground clearance of catalytic convertor in accordance with prior art and catalytic convertor in accordance with an embodiment of the present invention.
[044] As shown, Bar 1 represents the ground clearance C1 when a catalytic convertor is provided below the radiator unit in accordance with the prior art and Bar 2 represents the ground clearance C2 when the catalytic convertor 158 is provided between the radiator unit 144 and the right crankcase 140a in accordance with the present invention. As shown, the ground clearance C1 represented by Bar 1 is less than the ground clearance C2 represented by Bar 2. In other words, the present invention provides an improved ground clearance with respect to the prior art.
[045] Figure 12 illustrates a Bar graph plotting inlet temperature of the radiator unit in accordance with prior art and inlet temperature of radiator unit 144 in accordance with an embodiment of the present invention.
[046] As shown, Bar 1 represents the inlet temperature t1 of a radiator unit when a catalytic convertor is provided below the radiator unit in accordance with the prior art and Bar 2 represents the inlet temperature t2 of the radiator unit 144 when the catalytic convertor 158 is provided between the radiator unit 144 and the right crankcase 140a in accordance with the present invention. As shown, the inlet temperature of the radiator unit represented by Bar 1 is greater than the inlet temperature of the radiator unit 144 represented by Bar 2. In other words, the present invention results in decrease in inlet temperature of radiator unit 144, thereby improving the thermal efficiency of the radiator unit 144.
[047] Advantageously, in the present invention, the performance of first catalytic convertor 158 is improved as the same is closer to the exhaust port of the internal combustion engine 138. The first catalytic convertor 158 comes in contact with hot exhaust gases which considerably decreases the light off time of the first catalytic convertor 158, thereby, improving the quality of the emission. Also, due to the placement of the first catalytic convertor 158 between the right crankcase 140a and the radiator unit 144 and adjacent to the second bend 164 of the exhaust pipe 154, the heat from the radiator unit 144 does not directly affect the first catalytic convertor 158. Also, due to the placement of the first catalytic convertor 158 between the right crankcase 140a and the radiator unit 144, the ground clearance of the first catalytic convertor 158 is increased resulting in less damage of the first catalytic convertor 158. This results in better serviceability. Also, as the first catalytic convertor 158 extends in the vehicle longitudinal direction, the natural air only comes in contact with the end of the first catalytic convertor 158 facing the down frame 120. This results in fast activation of the first catalytic convertor 158, thereby improving the efficiency of the first catalytic convertor 158. As, the first catalytic convertor 158 is placed inside the exhaust pipe 154, the present invention results in effective usage of an expansion chamber volume in muffler unit 156.
[048] The present invention results in improved working of the O2 sensor. As the first catalytic convertor 158 is placed at a location adjacent to the second bend 164 of the exhaust pipe 154 and slightly overlaps with the radiator unit 144, the first catalytic convertor 158 is prevented from receiving direct heat from the radiator unit 144 and, therefore, results in efficient working of the O2 sensor. In prior arts, the catalytic convertor is placed directly below the radiator unit which results in excessive heat being radiated by the radiator unit onto the catalytic convertor. Also, owing to location of the first catalytic convertor 158 adjacent to the second bend 164, the first catalytic convertor 158 is not exposed to excessive natural air flow. This results in heat retention in the first catalytic convertor which is also necessary for efficient functioning of O2 sensor. It is, therefore, clear that O2 sensor is prevented from the excessive heat as well as natural air flow, which results in efficient working of the O2 sensor.
[049] The present invention recites providing a first catalytic convertor between the right crankcase and the radiator unit and below the cowl. It is to be understood that this arrangement of the first catalytic convertor does not lead to an increase in the width of the vehicle. In other words, there has been no change in the layout of the vehicle to accommodate the first catalytic convertor in accordance with the present invention.
[050] The present invention results in improved working/better thermal efficiency of the radiator unit 144. As the first catalytic convertor 158 is provided between the right crankcase 140a and the radiator unit 144 and below the cowl 168, the hot gas radiation effect to the inlet of the radiator unit 144 is avoided. Owing to this location, customer touch points of hot zones are avoided. In other words, the present invention protects the users from hot spots since the first catalytic convertor 158 is provided away from customer touch points. The present invention results in enhancement in thermal efficiency of the radiator unit 144 because the first catalytic convertor 158 is placed away from the inlet unit of the radiator unit 144. The present invention also results in reduced engine temperature since first catalytic convertor 158 is provided away from the cooling air inlet of the internal combustion engine 138. The present invention results in enhancement in aesthetics due to tucked-in muffler pipe 156a and the first catalytic convertor 158. The present invention results in reduced layout constraints as size of first catalytic convertor 158 is reduced by placing the first catalytic convertor closer to heat source.
[051] The claimed invention as discussed above is not routine, conventional, or well understood in the art, as the claimed invention enable the following advantages in addressing existing problems in conventional technologies. Specifically, the technical solutions of better serviceability of the first catalytic convertor 158, improved ground clearance of the first catalytic convertor 158, compact layout of the internal combustion engine 138, improvement in working of the radiator unit 144, improvement in the working of an O2 sensor, effective usage of expansion chamber of the muffler unit 156 and improvement in emission conversion by the first catalytic convertor 158 are achieved by the present invention.
[052] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.

List of Reference Numerals
100- vehicle
102- vehicle body frame
104- front fork
106-front wheel
108-seat
110- vehicle body cover
114- rear wheel
118- head pipe
120- down frame
122- handle bar
124- first lower frame
126- second lower frame
128-first rear frame
130- front cover
132-lower cover
134-rear cover
136- foot board
138- internal combustion engine
140- crank case
140a- right crankcase
144- radiator unit
146- exhaust emission control assembly
148- headlight
150-tail light unit
152- grab rail
154- exhaust pipe
154a- first end
154b- second end
156- muffler unit
156a- muffler pipe
158- first catalytic convertor
160- first portion of the exhaust pipe
162- first bend of the exhaust pipe
164- second bend of the exhaust pipe
166- second portion of the exhaust pipe
168- cowl
170- cover