Claims:I/We Claim:
1. A muffler assembly (155) for a vehicle (100), said muffler assembly comprising:
an exhaust pipe (401), said exhaust pipe (401) being connected on one side to an internal combustion engine (180);
a muffler body structure (407), said muffler body structure (407) including an outer muffler body (407b) and an inner muffler body (407c);
said muffler body structure (407) having a muffler rear member (407d),
said muffler rear member (407d) being the rearmost portion of said muffler assembly (155); and
a tail pipe (409), said tail pipe (409) forming an exhaust passage and being disposed within said muffler body structure (407); wherein,
a cover resonator (408) being disposed in between said tail pipe (409) and said inner muffler body (407c) of said muffler body structure (407),
an end cap cover assembly (406)
wherein,
said end cap cover assembly (406) includes a plurality of sub-covers (410, 411, 412), said end cap cover assembly (406) being adapted to substantially cover said muffler rear member (407d) of said muffler assembly (155);
wherein,
at least one sub cover (410, 411, 412) of said end cap cover assembly (406) being mounted on said cover resonator (408); and wherein,
at least two sub-covers (410, 411, 412) of said end cap cover assembly (406) being separated with a predetermined first annular gap (D1) defined by a predetermined distance for minimizing conductive heat transfer from said tail pipe (409) to said end cap cover assemble (406).

2. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said end cap cover assembly (406) being mounted on said cover resonator (408) by means of an edge contact.
3. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said outer muffler body (407b) and said inner muffler body (407c) of said muffler body (407) being configured with a predetermined third annular gap (D3), said predetermined third annular gap being defined by a predetermined distance.
4. The muffler assembly (155) for a vehicle (100) as claimed in claim 3, wherein at least one end of at least one sub-cover (410, 411, 412) of said end cap cover assembly (406) being supported in said predetermined third annular gap (D3).
5. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said predetermined fist annular gap (D1) ranging in between 5 mm to 20mm.
6. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein one end of said tail pipe (409) being connected to said muffler body structure 407 for receiving exhaust gases; and the other end of said tail pipe (409) being connected to the muffler rear member 407d, said tail piper 409 being configured to form a muffler outlet (405).
7. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said muffler assembly (155) being oriented inclinedly upwards towards a seat assembly (125) of said vehicle (100) and being disposed at a lateral side of a rear wheel (150).
8. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said end cap cover assembly (406) includes an inner cover (410), a middle cover (411), and an outer cover (412) configured to form a conductively insulating end cap cover assembly (406).
9. The muffler assembly (155) for a vehicle (100) as claimed in claim 3 and claim 8, wherein one edge of said inner cover (410) being disposed and supported within said predetermined third annular gap (D3) , and another edge of said inner cover (410) being mounted on a cover resonator (408), said other edge forming at a first contact region (A).
10. The muffler assembly (155) for a vehicle (100) as claimed in claim 9, wherein said first contact region (A) being a edge contact between an extended part (415) of said inner cover (410) and at least a portion of said cover resonator (408).
11. The muffler assembly (155) for a vehicle (100) as claimed in claim 3 and claim 8, wherein a one edge of said middle cover (411) being supported within said predetermined third annular gap (D3) and the other edge of said middle cover (411) being disposed between said inner cover (410) and said outer cover (412), said other edge being disposed at a pre-determined second annular gap (D2) from at least a portion of said cover resonator (408 ).
12. The muffler assembly (155) for a vehicle (100) as claimed in claim 11, wherein said predetermined second annular gap ranging between 2 mm to 20 mm.
13. The muffler assembly (155) for a vehicle (100) as claimed in claim 8, wherein a portion of said outer cover (412) being abuttingly supported on said middle cover (411) by means of one or more of a mounting contact (B), said mounting contact (B) being formed by one or more an outward extended portion of said middle cover (411) and at least one edge of said outer cover (412) being disposed at a predetermined fourth annular gap (D), said fourth annular gap (D4) being defined by a predetermined distance, said predetermined distance being from at least a portion of said cover resonator (415).
14. The muffler assembly (155) for a vehicle (100) as claimed in claim 13, wherein said predetermined fourth annular gap (D4) being at least half in dimension of a second pre-determined second annular gap (D2).
15. The muffler assembly (155) for a vehicle (100) as claimed in claim 13, wherein said middle cover (411) and said outer cover (412) being attached together by means of one or more end cover fasteners (413a, 413b).
16. The muffler assembly (155) for a vehicle (100) as claimed in claim 13, wherein said inner cover (410) being configured with a depressed region (416), formed substantially underneath said mounting contact (B).
17. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said exhaust pipe (401) being substantially covered by a front guard cover (403).
18. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein said muffler body structure (407) and said connecting portion (407a) of said muffler assembly (155) being covered by a leg guard cover (403).
19. The muffler assembly (155) for a vehicle (100) as claimed in claim 18, wherein said leg guard cover (403) includes a first cover (403a) and a second cover (403b), wherein said first cover (403a) covers a substantial portion of said muffler body (407) and said second cover (403b) covers said connecting portion (407a) and a substantial portion of said exhaust pipe (401) and said first cover (403a) and said second cover (403b) having a common mounting point.
20. The muffler assembly (155) for a vehicle (100) as claimed in claim 1, wherein a lambda sensor is positioned in a small chamber closer to an exhaust port (208), wherein the location of said lambda sensor is such that the exhaust flow is parallel to said lambda sensor axis, aiding in maximum heat transfer to said lambda sensor and resulting in faster activation time of a catalytic convertor.
, Description:TECHNICAL FIELD
[0001] The present subject matter described herein generally relates to a vehicle, and particularly but not exclusively relates to a muffler assembly for a straddle type vehicle.
BACKGROUND
[0002] Generally, in a two-wheeled vehicle a frame assembly extends rearward from a head tube. The frame assembly acts as a skeleton and a structural member for the vehicle that supports the vehicle loads. A front portion of the frame assembly connects a front wheel 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). An engine assembly is mounted to the frame assembly of the vehicle. The engine assembly is functionally connected to the rear wheel, which provides the forward motion to the vehicle. Typically, plurality of panels are mounted to the frame assembly of the vehicle that covers various vehicle parts mounted thereon.
[0003] Generally, an internal combustion engine of a vehicle receives an air-fuel mixture which is burnt to generate power for transmission of the vehicle. However, after the burning of the gases a substantial amount of exhaust in the form of harmful HC, NOx and CO is generated. This harmful exhaust leaves the internal combustion engine from an exhaust port provided on the internal combustion engine. An exhaust pipe extends in a downward rearwardly fashion from the exhaust port through which the gases travel to reach a muffler assembly. A set of catalysts are provided either in the exhaust pipe or in the muffler assembly, to oxidize the harmful gases. Mostly, the combination of exhaust pipe and muffler assembly constitute as an exhaust emission system used by the vehicle.
[0004] Conventionally, in two-wheeled vehicles, muffler assemblies are also provided to dampen noise arising from the engine and prevent the harmful oxides from entering in the atmosphere. Generally, the muffler assembly comprises of baffle pipes and chambers to increase the flow of the gas and dampen the sound coming from the engine, whereas it also comprises of catalytic converters to reduce and convert harmful NOx to N2 before it gets released into the atmosphere. Typically, the exhaust emission system is located at a rear portion of the vehicle disposed on either of its sides and the muffler assembly is provided on the right side of the vehicle when viewed from a rider’s perspective. The exhaust emission system also comprises of a tail pipe located at the end of the muffler assembly. The tail pipe is disposed after the baffle pipe such that, after travelling through the baffle pipe exhaust would flow out of tail pipe to enter atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The detailed description is described with reference to an embodiment of a two wheeled vehicle with an internal combustion engine along with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.
[0006] Figure. 1a to Figure. 1b illustrate a side view of a vehicle in accordance with an embodiment of the present invention.
[0007] Figure. 2 illustrates a side view of a power train of a vehicle, including an internal combustion engine, according to an embodiment of the present subject matter.
[0008] Figure. 3 illustrates a portion of a power train of a vehicle, according to an embodiment of the present subject matter.
[0009] Figure. 4 illustrates a muffler assembly of a vehicle in accordance with an embodiment of the present subject matter.
[00010] Figure. 5 to Figure. 6 illustrate a cross section of the rear portion of the muffler body of the muffler assembly of a vehicle in accordance with an embodiment of the present subject matter.
[00011] Figure. 7 illustrates an end cap cover assembly assembled to the rear portion of the muffler body as per an embodiment of the present subject matter.
[00012] Figure. 8 illustrates an exploded view of the muffler assembly as per an alternate embodiment of the present subject matter.
DETAILED DESCRIPTION
[00013] 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 that supports the vehicle loads. The frame structure also comprises of a down tube extending in a downward and rearward direction form the head tube, and a main tube extending in a straight and forward direction from the head tube. 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). The frame assembly comprises of a head tube disposed in a front portion of the vehicle, wherein a down tube extends from the head tube in a downward and rearward manner. A main tube is also provided which extends in a substantial straight and rearward fashion from the head tube. In addition to it, a pair of cross tubes are provided at a rearmost portion of the vehicle to accommodate a seat assembly. Moreover, the two wheeled vehicle also comprises of an engine assembly mounted to it.
[00014] Mostly, it is the internal combustion engine which generates power for the vehicle. An air-fuel mixture is supplied to the internal combustion engine by means of a carburetor or an injector. Thereafter combustion of the air fuel mixture takes place so that a piston disposed in the internal combustion engine is set into motion. The piston is operated in a linear motion, after which said linear motion is converted to a rotational motion of a crankshaft, which is finally transferred to the rear wheel.
[00015] Reducing emission to as minimum as possible is often the goal any vehicle manufacturer. Emissions are reduced by enhancing combustion efficiency and / or carrying out after treatment of exhaust output. Additionally, evaporative emission reduction is also being pursued by various known means.
[00016] Typically, any two-wheeled vehicle comprises of an exhaust emission system extending in a downward manner from the internal combustion engine towards a rear portion of the vehicle. The unburnt air-fuel mixture in form of exhaust gases being emitted from the internal combustion engine is emitted into the atmosphere after the oxidation reaction happening in the exhaust emission system. Typically, a catalytic converter is provided in an exhaust pipe or a muffler assembly, to enable oxidation of the unburnt gases such that the toxic gases are converted to less harmful gases. The muffler assembly is also meant for achieving overall noise reduction.
[00017] Typically, in a two-wheeled straddle-ride type motor vehicle, an engine assembly is mounted to the frame assembly in a front portion. A fuel tank is disposed above the engine assembly. A carburetor or the like supplies air fuel mixture to the engine assembly. Combustion of air-fuel mixture occurs in the engine assembly and a piston disposed in the engine assembly is set to operate in a linear motion. The linear motion of the piston is converted into rotational motion and the resultant motion is transferred to the rear wheel thereby resulting in motion of the vehicle. In addition, this results in generation of required power and torque by the engine assembly.
[00018] After all the reactions and processes, the exhaust leaves the exhaust emission system at a great speed and pressure. Since during running of the vehicle, a large amount of heat is also generated inside the combustion chamber of the internal combustion engine, the exhaust gases passing through the muffler assembly are also at high temperature. Resultant to which, the average temperature of the muffler assembly is usually 300 to 500 degrees. This temperature can also rise to 1200 degrees in worst case scenarios, where the vehicle has been running for a considerable time. Certain known arts suggest that there are many other factors which determine the exhaust gases temperature that in turn determine the muffler assembly temperature and because of which the temperature of the exhaust gasses and the muffler assembly may vary. These factors include engine size, engine speed, engine load, inlet air temperature.
[00019] Since the temperature of the muffler assembly is considerably high to cause serious burns to a person coming in contact with it. Some known arts disclose, usage of one or more covers which are provided on the surface of the muffler assembly to avoid such accidents. Such covers include a front guard cover that covers the exhaust pipe of the muffler assembly, a leg guard cover that covers a portion of the exhaust pipe and a substantial portion of the middle portion of the muffler body that is exposed towards the pillion rider.
[00020] However, usually the rear portion of the muffler body is left unattended mostly because the rear portion includes a muffler outlet and providing of a cover in the rear region may provide an obstruction for the passage of the exhaust gasses through the muffler outlet.
[00021] Other known arts disclose about a muffler assembly having a muffler body extending rearwards along the right side of the rear wheel of the vehicle, such that the muffler body is aggressively inclined towards the seat assembly for a sporty layout and look of the vehicle. This aggressive inclination is usually done for enhancing aesthetic appeal, accommodating the rear wheel hugger and a larger width tire of the rear wheel.
[00022] The aggressive inclination of the muffler body towards the seat assembly brings the muffler assembly in proximity with the seat assembly as compared to other known vehicles. Also, such aggressive inclination considerably exposes the rear portion of the muffler body towards the seat assembly. This proximation of the muffler assembly along with considerable exposure of otherwise uncovered rear portion of the muffler body exposes a considerable portion of the muffler body of the muffler assembly to be in proximity of the leg of the pillion rider seated on the pillion portion of the seat assembly. This increases the risk for the pillion rider to accidently get serious burns on his legs, in situations where he accidently comes in contact with the exposed high temperature portions of the muffler assembly, particularly the rearmost portion of the muffler assembly.
[00023] Hence there is a need to effectively insulate the rearmost portion of the muffler assembly from the body of the pillion rider as well as provide improved solution to considerably minimise the overall average temperature of the rearmost portion of the muffler assembly.
[00024] Hence, there is a need of addressing the above circumstances and other problems of known arts.
[00025] The present subject matter has been devised in view of the above circumstances as well as solving other problems of the known art.
[00026] The present subject matter includes a muffler assembly for a vehicle comprising an exhaust pipe, a muffler body structure, and a tail pipe. The exhaust pipe is connected on one side to an internal combustion engine. The muffler body structure includes an outer muffler body, and an inner muffler body. The muffler rear member being the rearmost portion of the muffler assembly. The tail pipe forms an exhaust passage disposed within the muffler body structure; wherein a cover resonator is being disposed in between the tail pipe and the inner muffler body of the muffler body structure. A predetermined third annular gap D3 exists, defining a predetermined distance, in between the outer muffler body and the inner muffler body of the muffler body structure.
[00027] One end of the tail pipe is connected to the muffler body structure at a connecting portion for receiving exhaust gases and the other end of the tail pipe is configured as a muffler outlet.
[00028] As per another aspect of the present subject matter, the muffler rear member of the muffler assembly includes said muffler outlet. The muffler rear member is substantially covered by an end cap cover assembly. As per an embodiment, the end cap cover assembly includes a plurality of sub-covers. At least one sub cover of the end cap cover assembly is mounted on a cover resonator via a point contact while maintaining a predetermined first annular gap D1 in between at least two sub-covers of the end cap cover assembly, said predetermined first annular gap D1 is between the two sub-covers of end cap cover assembly having a predetermined distance. One end of at least one sub-cover of the end cap cover assembly is supported in between the predetermined third annular gap D3. The predetermined third annular gap exists in between the outer muffler body and the inner muffler body.
[00029] As per another aspect of the present subject matter, at least one sub-cover of the end cap cover assembly is mounted on the cover resonator via a point contact while maintaining a predetermined annular gap of range 5mm to 20mm in between the at least two covers of the end cap cover assembly.
[00030] As per an embodiment the muffler assembly is oriented inclinedly upwards in an aggressive manner to be proximal towards a seat assembly of the vehicle and is disposed at a lateral side of a rear wheel.
[00031] As per another aspect the end cap cover assembly includes an inner cover, a middle cover, and an outer cover. At least one end of the inner cover is supp on a portion of inner muffler body and said support being located within the predetermined third annular gap D3. At least other end of the inner cover is mounted on a cover resonator via a first contact region, wherein the first contact region being substantially a point contact between an extended part of the inner cover and at least a portion of the cover resonator.
[00032] As per another aspect, at least one end of the middle cover is also supported within the predetermined third annular gap D3 and the other end of said middle cover being disposed open between the inner cover and the outer cover. The other end of the middle cover forms a pre-determined second annular gap D2 from at least a portion of the cover resonator. As per an embodiment, the pre-determined second annular gap D2 ranges between 2 mm to 20 mm.
[00033] As per another aspect the middle cover and the outer cover are held together by means of a mounting contact. The mounting contact is formed by at least an outward extended portion of the middle cover and at least a portion of the outer cover. At least a portion of the at least a portion of the outer cover is abuttingly supported on at least a portion of the middle cover by means of one or more attaching means like an end cover fastener.
[00034] The outward extended portion of the middle cover creates the first predetermined annular gap D1 annular gap thereby creating a thermal separation between the two sub-covers of the end cap cover assembly. As per an embodiment, the inner cover includes a depressed region formed substantially underneath the mounting contact.
[00035] As per another aspect at least one end of the outer cover is disposed forming a predetermined fourth annular gap D4 from at least a portion of the cover resonator. As per an embodiment, the predetermined fourth annular gap D4 by a predetermined distance, which is at least half of the distance of the pre-determined second annular gap D2. As per an aspect the one end of the outer cover forming annular gap D4 being proximal to the tail pipe and proximal to the exit point of the exhaust assembly. As a result of the present invention, the end cover assembly being formed of three sub-covers and the three sub-covers being mounted with predetermined annular gaps formed, the cover assembly is effectively thermally insulated from the excessive heat of the exhaust gases. The outer cover of the cover assembly is thereby operated at a considerably lower temperature thereby improving the safety of the pillion rider in case of accidental contact with it. Also, the present invention enables a more aggressive layout orientation of the muffler assembly thereby enabling a laterally compact layout of the vehicle which is desirable to achieve good ride and handling characteristics of the vehicle. The present invention also enables more freedom for the layout design of the vehicle by bringing the vehicle mass like muffler assembly as close as possible to the vehicle center of gravity in a lateral direction which is of added important for a performance straddle type vehicle like a motorcycle without increasing safety risk to the pillion rider. AS a result of the present invention, owing to the so formed thermal insulation barrier, enables minimizing the peak temperature being reached by the cover assembly, thereby enabling it to also cool down faster which further reduces the chance of major burn injury to the pillion rider or any other person in vicinity of the muffler assembly when the vehicle is in a parked condition.
[00036] As per another embodiment, the muffler assembly includes a front guard cover a leg guard, and an end cap cover assembly. The front guard cover covers the exhaust pipe. The leg guard cover covers the muffler body and the connecting portion of the muffler assembly and/or portion of the exhaust pipe. The end cap cover assembly covers the rear portion of the muffler assembly.
[00037] As per another embodiment, the leg guard cover includes one or more covers.
[00038] Exemplary embodiments detailing features regarding the aforesaid and other advantages of the present subject matter will be described hereunder with reference to an embodiment of a motorcycle types two wheeled vehicle along with the accompanying drawings. Various aspects of different embodiments of the present invention will become discernible from the following description set out hereunder. Rather, the following description provides a convenient illustration for implementing exemplary embodiments of the invention. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof. Further, it is to be noted that terms “upper”, “down”, “right”, “left”, “front”, “forward”, “rearward”, “downward”, “upward”, “top”, “bottom”, “exterior”, “interior” and like terms are used herein based on the illustrated state or in a standing state of the two wheeled vehicles with a driver riding thereon. Furthermore, arrows wherever provided in the top right corner of figure(s) in the drawings depicts direction with respect to the vehicle, wherein an arrow F denotes front direction, an arrow R indicates rear direction, an arrow Up denotes upward direction, an arrow Dw denotes downward direction, an arrow RH denotes right side, and an arrow LH denotes left side. 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.
[00039] Figure 1a to Figure 1b illustrates a side view of a vehicle 100 in accordance with an embodiment of the present invention. The vehicle 100 includes a frame assembly 110 to support different parts of the vehicle 100. In an upper portion of the frame assembly 110, a handlebar assembly 115 is rotatably integrally connected to the steering shaft (not shown). The handlebar assembly 115 is used to steer the vehicle 100 and is connected to a front wheel 185 through the steering shaft (not shown) and a front fork assembly (not shown). An upper portion of the front wheel 185 is covered by a front fender 190 which prevents mud and water from getting deflected towards the steering shaft (not shown). Further, the front fork assembly is supported on the front fender 190 by means of a brace fender (not shown).
[00040] In a front portion of the frame assembly 110 a fuel tank assembly 120 is arranged immediately behind the handlebar assembly 115 and is disposed over a first power source, for example an internal combustion engine 180. A seat assembly 125 is placed behind the fuel tank assembly 120. The seat assembly 125 includes a front rider seating portion and a pillion rider seating portion. The pillion rider seating portion is placed on the rear part of the frame assembly 110, where the rear part of the frame assembly 110 is covered by the tail cover assembly 130. Area below the seat assembly 125 and the fuel tank assembly 120 of the vehicle 100 is covered on both sides by a cover frame assembly 170. The cover frame assembly 170 includes the one or more side covers.
[00041] For the safety of the rider and in conformance with the traffic rules, a headlamp assembly 105 that includes a headlamp and front turn indicator lights 140a are provided in the front portion of the vehicle 100. On the rear portion of the two wheeled vehicle 100 a tail lamp (not labeled) and rear indicator light 140b are provided on the rear portion of the tail cover assembly (not shown).
[00042] Suspension systems are provided for comfortable steering of the two wheeled vehicle 100 on the road. A front suspension assembly 195 serves as rigidity component for the front portion of the vehicle 100 just like the frame assembly 110. The front suspension assembly 195 clamped to the head tube (not shown) through an upper bracket (not shown) and a lower bracket (not shown) is capable of being moved to the left and right. Further, a rear suspension system 160, which is a hydraulic damped arrangement, is connected to the frame assembly 110. The rear suspension system 160 comprises of at least one rear suspension 160 preferably disposed centrally in the longitudinal mid plane of the vehicle 100. However, in a vehicle 100 with two rear suspensions, the same may be disposed on the left side and the right side respectively of the vehicle 100.
[00043] Further, a swing arm (not shown) extending rearwards is swingably connected to a lower rear portion of the vehicle 100. The rear wheel 150 is rotatably supported at a rear end of the swing arm. Power from the internal combustion engine 180 is transmitted to the rear wheel 150 through a power drive mechanism, such as a drive chain, to drive and rotate the rear wheel 150. A center stand 165 is provided in between the front wheel 185 and the rear wheel 150 for parking the vehicle 100.
[00044] A rear wheel hugger 145 for covering an upper side of the rear wheel 150 is mounted to a rear portion of the vehicle 100 to prevent mud and water splashed by the rotating rear wheel 150 from entering the muffler assembly 155, the internal combustion engine 180 and other parts disposed close by. To enhance the overall aesthetics of the vehicle 100 and to prevent undesired foreign particles from entering parts of the vehicle 100, a plurality of rear covers (not labeled) is attached to a rear portion of the frame assembly 110.
[00045] Figure 1b illustrates a vehicle 100 without cover frame assembly 170 (as shown in Figure 1a). Figure 1 b further illustrates that the first power source, for example the internal combustion engine 180 is mounted to a front lower portion of the frame assembly 110 by means of an engine mounting bracket (not shown). The internal combustion engine 180 is partially covered on the lower side of the internal combustion engine 180 by an engine cover 175. The internal combustion engine 180 is equipped with an exhaust system, for example a muffler assembly 155, that includes an exhaust pipe 401 connected to the internal combustion engine 180 and a muffler body structure 407 connected to the exhaust pipe 401 and a muffler rear member 407d. In the present illustrated figure, the muffler body structure 407 of the muffler assembly 155 extends rearwards along the right side of the rear wheel 150, such that the muffler body structure 407 is aggressively inclined towards the seat assembly 125 of the vehicle 100 and disposed in close proximity to a longitudinal central plane of the vehicle. This aggressive inclination is usually also done for enhancing aesthetic appeal and accommodating the rear wheel hugger 145 and a larger width tire of the rear wheel 150.
[00046] Figure 2 illustrates a side view of a power train of a vehicle 100, including an internal combustion engine 180, according to an embodiment of the present subject matter. The powertrain encompasses every component that converts an engine’s 180 power into the movement of the vehicle 100. This includes an engine 180, a transmission system, driveshaft, differentials, axles; basically anything from the engine 180 through to the rotating wheels of the vehicle 100.
[00047] The internal combustion engine 180 includes a cylinder block 202 supported by a crankcase assembly 201 of the internal combustion engine 180. The cylinder block 202 defines a cylinder portion at which a piston can perform reciprocating motion. A cylinder head 203 is mounted to the cylinder block 202 and the cylinder head 203 acts as one end of the cylinder portion. The cylinder block 202 is provided with cooling fins 206 and the cylinder head 203 may be provided with the cooling fins 206.
[00048] The internal combustion engine 180 comprises a piston (not shown) performing a reciprocating motion in the cylinder portion due to force imparted to it by the combustion of air-fuel mixture. This reciprocating motion is converted and transferred to a rotary motion of a crankshaft 210 through a connecting rod (not shown). Further, a cylinder head-cover 204 is mounted to the cylinder head 203. The crankcase assembly 201 is made up of left-side crankcase and right-side crankcase. The crankcase assembly 201 rotatably supports the crankshaft 210. Further, an electric machine like a magneto assembly 211 or an integrated starter generator is mounted to the crankshaft 210. The magneto assembly 211 during operation is used to charge a battery (not shown).
[00049] The crankshaft 210 includes a crankpin bore (not shown). As per an embodiment, the hardening of crankpin bore increases the yield strength and hence avoid the permanent deformation at crankpin bore, because the hardness in the crank pin bore avoids distortion while pressing crankpin in the crankshaft 210. And because of this crankshaft 210 web deflection is avoided. For example, this hardening is done by providing a heat treatment for achieving a hardness in range of 400-550 Hv at 0.3 kg load and effective case depth at 0.5-1.5 mm.
[00050] The cylinder head 203 includes an intake port 205 and an exhaust port 208 (shown in Figure 3) that are provided on a first face and a second face of the cylinder head 203. In the present embodiment, the first face is an upward facing side and the second face is a downward facing side thereof. Further, the cylinder head 203 supports a camshaft assembly (not shown) that is capable of operating intake valve(s) and exhaust valve(s) of the internal combustion engine. As per another embodiment, a lambda sensor is positioned in a small chamber closer to the exhaust port 208. The location of the lambda sensor is such that the exhaust flow will be parallel to the sensor axis. This helps in maximum heat transfer to the sensor resulting in faster activation time of a catalytic convertor (CAT CON). Along with the sensor, the CAT CON is provided in the same chamber such that the chamber creates an annular space around the CAT CON, this helps in movement of exhaust gas around the CAT resulting in faster activation time. Annular space also helps in heat retention which helps in less heat feel to the customer in an undesirable event of contact of customer with the muffler assembly (155).
[00051] Figure 3 illustrates a portion of a power train of a vehicle 100, according to an embodiment of the present subject matter. The power train of a vehicle 100 includes a gear oil pump drive connected to the crankshaft 210 and rotates integrally with it. The gear oil pump drive includes a primary driving gear (not shown). The primary driving gear acts a primary drive and can transfer rotational force or torque to a primary driven gear. The primary driven gear is thus operably connected to the crankshaft 210 (shown in Figure 2).
[00052] The camshaft assembly (not shown) is rotatably coupled to the connecting rod (not shown). A cam chain (not shown) operably connects the crankshaft 210 and camshaft assembly. A driven sprocket of the camshaft assembly is configured to be meshed with the primary driving gear (not shown) and the driven sprocket (not shown) transfers the rotary motion of the crankshaft 210 to the camshaft assembly.
[00053] Typically, the transmission assembly of the power train includes a spring-loaded multiplate friction clutch assembly 207 fixedly attached to the left-hand portion of the crankshaft 210 using plurality of fastening means. The right-hand side of the crankcase 210 encloses a dry magneto assembly 211. The dry magneto assembly 211 is configured to rotate along with the crankshaft 210 to generate power which recharges the battery (not shown).
[00054] The clutch assembly 207 further includes one or more clutch plates 207a, a clutch hub 207, and a flywheel (not shown). The clutch assembly 207 is fixedly attached by fastening means to an input shaft (not shown). The clutch assembly 207 is selectively engaged disengaged to ensures that power transmission from the internal combustion engine 180 to the rear wheel 150 (as shown in Figure 1).
[00055] The cylinder head 203 (shown in Figure 2) comprises a valve train arrangement to control opening and closing of intake and exhaust valves present at the intake port 205 (shown in Figure 2) and exhaust ports 208 thereby controlling intake of air-fuel mixture and outlet of exhaust gases.
[00056] As shown in Figure 4, The exhaust pipe 401 of the muffler assembly 155 is connected to the exhaust port 208 to provide a passage for passing the exhaust gases from the internal-combustion engine 180 to primarily attenuate (reduce) the airborne noise of the internal combustion engine 180.
[00057] The noise of the exhaust gas exiting the engine at high speed is abated by a series of passages and chambers lined with roving fiberglass insulation and resonating chambers, for example, by means of a cover cover resonator (408) (shown in Figure 4), harmonically tuned to cause destructive interference, wherein opposite sound waves cancel each other out.
[00058] As per an embodiment, two catalysts are disposed in the muffler assembly 155. One of the catalysts, herein called as a pre catalyst is disposed in the exhaust pipe 401 and another catalyst herein called as a main catalyst is disposed in the muffler body structure 407. The pre-catalyst which helps in partial conversion of emissions, is located outside the body of engine 180 and above the crank axis of the crankshaft assembly (210) and being towards the cylinder head 203 when viewed from top side of the engine 180. This partial conversion of emissions can only be achieved when the pre catalyst achieves an ideal temperature called as the light off temperature. In order achieve a faster light off temperature the pre-catalyst is positioned closer to the engine exhaust port 208.
[00059] Once the exhaust gasses are formed a large amount of heat is also generated inside the combustion chamber of the internal combustion engine 180, the exhaust gases passing through the muffler assembly 155 is also at high temperature. There are many other factors which determine the exhaust gases temperature that in turn determine the temperature of the muffler assembly 155 and because of which the temperature of the exhaust gasses and the muffler assembly 155 may vary. These factors include engine size, engine speed, engine load, inlet air temperature.
[00060] Figure 4 illustrates a muffler assembly 155 of a vehicle 100 in accordance with an embodiment of the present subject matter. As shown in Figure 1, the vehicle 100 consists of a fuel tank assembly 120, an engine 180, and a muffler assembly 155. The muffler assembly 155, includes an exhaust pipe 401, a muffler body structure 407, a muffler rear member 407d and a tail pipe 409 (shown in Figure 5). The muffler assembly 155 is supported on the frame assembly 110 (shown in Figure 1b) of the vehicle 100 through a mounting means 404, which is fixed, to the muffler body structure 407. The muffler body structure 407 includes an outer muffler body 407b, and an inner muffler body407c. muffler rear member 407d. The exhaust pipe 401 is connected to the muffler body structure 407 at a connecting portion 407a. The muffler body structure 407 holds a tail pipe 409 within the muffler body 407. Therefore, one end of the tail pipe 409 is also connected to the muffler body structure 407 at the connecting portion (not shown) and the other end of the tail pipe 409 is configured as a muffler outlet 405.
[00061] The muffler rear member 407d is the rearmost portion of the muffler assembly 155 towards the atmosphere away from the exhaust pipe 401.
[00062] One end of the exhaust pipe 401 is connected to the exhaust port 208 (shown in Figure 3) of the engine 180. The fuel from the fuel tank assembly 120 that gets inside the engine 180 undergoes combustion from which mechanical power is generated and it is transferred to the wheels. Since combustion of fuel is an exothermic reaction; a large amount of heat along with exhaust gasses is generated in this process. Then the high temperature exhaust gas pass through a catalytic convertor (not shown), which is placed inside the muffler assembly 155 and is released into the atmosphere through a muffler outlet 405.
[00063] The carrying away of burnt and unburnt gases during combustion through the exhaust muffler, increases the temperature of the muffler assembly 155 and consequently the muffler assembly 155 attains a very high temperature while the vehicle 100 is in use. Resultant to which the average temperature of the muffler assembly 155 can rise to 300 to 500 degrees. This temperature can also rise to 1200 degrees in worst case scenario when the vehicle 100 has been running for a considerable time period.
[00064] As shown in Figure 1b, the muffler body structure 407 of the muffler assembly 155 extends rearwards along the right side of the rear wheel 150, such that the muffler body structure 407 is aggressively inclined towards the seat assembly 125 and in close proximity to a longitudinal central plane of the vehicle 100. This aggressive inclination is usually done for enhancing aesthetic appeal and accommodating the rear wheel hugger 145 and a larger width tire of the rear wheel 150.
[00065] The aggressive inclination of the muffler body 407 towards the seat assembly 125 brings the muffler assembly 155 in proximity with the seat assembly 125 as compared to conventional and non-sporty vehicles. This proximation of the muffler assembly 155 with the seat assembly 125 exposes a considerable portion of the muffler rear member 407d of the muffler assembly 155 in proximity of the leg of the pillion rider seated on the pillion portion of the seat assembly 125. This increases the risk for the pillion rider to accidently get serious burns on a body part e.g. legs if he / she accidently comes in contact with the exposed high temperature portions of the muffler assembly 155.
[00066] Therefore, one or more insulating covers are provided on the surface of the muffler assembly 155 to avoid such accidents. Such insulating covers include a front guard cover 402 that covers the exhaust pipe 401 of the muffler assembly 155, a leg guard cover 403 that covers a portion of the exhaust pipe 401 and a substantial portion of the muffler body 407 that is exposed towards the pillion rider. In another embodiment, the present subject matter provides an improved end cap cover assembly 406 that covers a muffler rear member 407d of the muffler body structure 407, in proximity of the muffler outlet 405.
[00067] Figure 5 to Figure 6 illustrates a cross section of the muffler rear member 407d of the muffler body structure 407 of the muffler assembly 155 of a vehicle 100 in accordance with an embodiment of the present subject matter. For the purpose of bringing clarity the cross section is divided into two equal parts by means of a dotted first plane XY passing centrally and laterally through an axis of the tail pipe (409). The region of the muffler body above the first plane XY is herein called as an upper region and the region of the muffler body below the first plane XY is herein called as a lower region. Figure 6 illustrates only the upper region of the cross section of the muffler body 407 of the vehicle 100.
[00068] A tail pipe 409 is disposed within the muffler body structure 407 of the muffler assembly 155. The tail pipe 409 acts as an exhaust passage disposed within the muffler body structure 407, such that one end of the tail pipe 409 is connected to the muffler body structure 407 for receiving exhaust gases, and the other rear end of the tail pipe 409 is connected to the muffler rear member 407d of the muffler body 407, said tail pipe 409 being configured to form a muffler outlet 405.
[00069] The muffler rear member 407d of the muffler body structure 407 includes the muffler outlet 405 and the muffler rear member 407d except the muffler outlet 405 is covered by an end cap cover assembly 406. The end cap cover assembly 406 includes a plurality of sub-covers (410, 411, 412). To avoid heat conduction from the tail pipe 409 to the end cap cover assembly 406, the tail pipe 409 is indirectly mounted to the end cap cover assembly 406 by means of a cover resonator 408, as the tail pipe 409 is disposed within a cover resonator 408 of the muffler body 407.
[00070] At least on one end of at least one sub-cover (410, 411, 412) of the end cap cover assembly 406 being supported in between the outer muffler body 407b and the inner muffler body 407c having a predetermined third annular gap D3 formed between them. And at least one sub-cover (410, 411, 412) of the end cap cover assembly 406 is mounted on the cover resonator 408 via an edge contact while maintaining a predetermined second annular gap D2 between at least two sub-covers (410, 411, 412) of the end cap cover assembly 406 and the cover 408. The point contact between the cover resonator 408 and the end cap cover assembly 406 in addition to the predetermined first annular gap D1 created in between the plurality of sub-covers of the end cap cover assembly 406, provides minimum thermal conduction contact between the sub-cover members and thereby aids in minimizing heat transfer by means of conduction.
[00071] As per an embodiment, the predetermined first annular gap D1 defined by a predetermined distance in between the sub-covers (410, 411, 412) of the end cap cover assembly 406 ranges in between 5 mm to 20 mm.
[00072] The tail cover assembly includes an inner cover 410, a middle cover 411, and an outer cover 412. One edge of the inner cover 410 being supported on muffler inner body 407c. Muffler outer body 407b being disposed to form the predetermined third annular gap D3 between them. The one edge of inner cover 410 being disposed in the predetermined annular gap D3 and at least another edge of the inner cover 410 being attached on a cover resonator 408 via a first contact region A. The first contact region A being an edge contact between an extended part 415 of the inner cover 410 and at least a portion of the cover resonator 408. This is done to minimize heat conduction from the tail pipe 409 to the inner cover 410 via the cover resonator 408.
[00073] One end of the middle cover 411 is disposed unsupported between said inner cover and the outer cover so as to form a predetermined second annular gap D2 annular gap, said second annular gap D2 being between said one end of middle cover 411 and at least a portion of a cover resonator (415) and the other end of the middle cover 411 being disposed in said predetermined third annular gap D3. As per an embodiment, the other end of the middle cover 411 being collocated and coinciding with the one edge of said inner cover 410 so as to be attached to the one edge of said inner cover 410 at its inner surface and the muffler outer body 407b at its outer surface. As per an embodiment, the predetermined annular gap D2 ranges between 2 mm to 20 mm.
[00074] The outer cover 412 is supported on the middle cover 411 by means of a mounting contact B and the outer cover 412 is disposed offset from the middle cover. One edge of the outer cover 412 forms a predetermined fourth annular gap D4 from at least a portion of the cover resonator 415 on at least one end.
[00075] As per an embodiment, the predetermined fourth annular gap D4 is at least half of the second pre-determined distant D2.
[00076] The second contact B is created by at least an outward extended portion of the middle cover 411 and at least a portion of the outer cover 412 being in abutting contact with the outward extended portion of the middle cover 411. , The middle cover 411 and the outer cover 412 are fastened together by suitable one or more attaching means e.g. pair of fasteners (413a, 413b) one each on the upper portion and the lower portion of the end cap cover assembly 406. The outward extended portion of the middle cover forms a predetermined first annular gap D1 between the rest of the portion of the middle cover 411 and the outer cover 412 thereby achieving a conductively insulating efficient end cap cover assembly 406
[00077] Since the middle cover 411 and the outer cover 412 do not have any direct contact with the tail pipe 409 of the muffler assembly 155, also the first predetermined annular gap D1 is always maintained in between the middle and outer sub-covers, this aids in further reduction of conduction of heat in between the three sub-covers, as obviation of any contact of the middle cover 411 and outer cover 412 with the tail pipe 409 is ensured.
[00078] As per an additional embodiment, the inner cover 410 includes a depressed region 416, formed substantially beneath / underneath the mounting contact B. This depressed region 416 further enables passage of cooling air between the middle cover 411 and the inner cover 410. Thereby the air flow is not obstructed because of the end cover fastener 413a used.
[00079] The inner cover 410 and the middle cover 411 is sealed at one end because the inner cover 410 and the middle cover 411 at their one edge are being integrally attached with the muffler outer body 407b and the muffler inner body 407c. The other edge of inner cover 410 is having an edge contact with the cover resonator 408 and has no contact with the tail pipe 409. The other edge of the middle cover 411 has no contact with the tail pipe nor the cover resonator. Also, there is no other contact between the inner cover 410 and the middle cover 411 except the first edge. Thereby, one way passage is created in between the inner cover 410 and the middle cover 411 while having an enlarged annular gap in between because of the mounting contact B. Resultant to which, air gushes in between the passage while vehicle is running. However, the air fails to escape easily because of the sealed end and thereby provides an additional air insulation in between the two covers and thus providing minimum transfer of heat to the outer cover 412 through conduction.
[00080] Therefore, the present claimed end cap cover assembly 406 enables considerable reduction of the temperature of the outer cover 412 of the end cap cover assembly 406. For example, reduction of temperature up to 150 degrees may be achieved. Such reduced temperature ensures that the leg of the rider or the pillion rider is efficiently safeguarded from excessive heat burns caused by accidental contact with the muffler rear member 407d of the muffler assembly 155.
[00081] Figure 7 illustrates an end cap cover assembly 406 assembled to the muffler rear member 407d of the muffler body 407 as per an embodiment of the present subject matter. The end cap cover assembly 406 is integrated at least on one end with the muffler body structure 407 and covers a substantial portion of the muffler rear member 407d except the portion including the muffler outlet 405, for enabling smooth passage of the exhaust gasses to the atmosphere. The end cap cover assembly 406 is attached at least on two places by means of one or more end cover fasteners (413a, 413b).
[00082] Figure 8 illustrates an exploded view of the muffler assembly 155 as per an alternate embodiment of the present subject matter. As per the alternate embodiment, the leg guard cover 403 protects the rider from heat burns due to accidental contact with the muffler outer body 407b of the muffler body structure 407. The leg guard cover 403 includes a first cover 403a and a second cover 403b. The first cover 403a covers a substantial portion of the muffler body structure 407. The second cover 403b covers the connecting portion 407a and a substantial portion of the exhaust pipe 401.
[00083] As per another aspect of preset invention, the first cover 403a and the second cover 403b are assembled by means of common mounting arrangements. This will reduce number of parts required for assembling of two covers. Further such integrated mounting arrangement also reduces the part variety, assembly time, cost & weight of the muffler assembly 155. This will also help in reducing vibration between the covers present in the overlapping regions.
[00084] The muffler rear member 407d of the muffler body 407 is covered by the end cap cover assembly 406 and the rest of the substantial portion of the exhaust pipe 401 is covered by the front guard cover 402.
[00085] 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.
 
LIST OF REFERENCE NUMERAL
100 – Vehicle
105- Head lamp
115- Handle bar
120- Fuel tank
125- Seat assembly
130- Tail cover assembly
140a- Front indicator light
140b- Rear Indicator light
145- Rear wheel hugger
150- Rear wheel
155- Muffler assembly
160- Rear suspension system
165- Center stand
170- Cover frame assembly
175- Engine cover
180- Internal combustion engine
185- Front wheel
190- Front fender
195- Front suspension assembly
201- Crank case
202- Cylinder block
203- Cylinder head
204- Cylinder head cover
205- Intake port
206- Cooling fins
207- Clutch assembly
207a- Clutch plates
207b- Clutch hub
208- Exhaust port
210- Crankshaft
211- Magneto assembly
212- Oil sump
214- Oil drain plug
401- Exhaust pipe
402- Front guard cover
403- Leg guard cover
403a- First cover
403b- Second cover
404- Mounting means

405- Muffler outlet
406- Tail pipe end cover
407- Muffler body
407a- Connecting portion
407b- Outer muffler body
407c- Inner muffler body
407d- Muffler rear member
408- Cover cover resonator
409- Tail pipe
410- Inner cover
411- Middle cover
412- Outer cover
413a, b- End cover fastener
415- Extended part
416- Depressed region
A- First contact region
B- Mounting contact
XY- First plane
D1: First annular gap
D2: Second annular gap
D3: Third annular gap
D4: Fourth annular gap