Claims:
We Claim:
1. An exhaust emission system for an internal combustion engine (110) of a vehicle (100), wherein said exhaust emission system comprises:
a muffler assembly (185) enabled for noise reduction of said multi-wheeled vehicle (100) and oxidizing and reduction of exhaust coming from said internal combustion engine (110);
an exhaust pipe (195) comprising an upstream portion (200) being connected to said internal combustion engine (110) and a downstream portion (205) being connected to said muffler assembly (185) provided for flow of exhaust from said internal combustion engine (110) to said muffler assembly (185); and
a pseudo hermetic multi-functional body guard (225) to cover said muffler assembly (185), wherein said body guard (225) comprises a plurality of openings (260, 265, 270) being formed at a front portion, top portion and rear portion of said body guard (225) when seen from a front side of said vehicle (100).
2. The exhaust emission system as claimed in claim 1, wherein said muffler assembly (185) is entirely circumscribed by said body guard (225) to trap heat being radiated therein.
3. The exhaust emission system as claimed in claim 1, wherein said muffler assembly (185) comprises of a cylindrically shaped main body (210) with a first conical shaped profile (215) formed at a front portion of said cylindrically shaped main body (210) when seen from a front side of said multi-wheeled vehicle (100), and wherein said muffler assembly (185) comprises of a second conical shaped profile (220) formed on a rear portion of said cylindrically shaped main body (210) when seen from a front side of said multi-wheeled vehicle (100).
4. The exhaust emission system as claimed in claim 1 and claim 3, wherein said body guard (225) comprises of a first curved surface (230) covering a top portion of said cylindrical shaped main body (210), and a second curved surface portion (235) covering a bottom portion of said cylindrical shaped main body (210).
5. The exhaust emission system as claimed in claim 1 and claim 3, wherein said body guard (225) comprises of a first conical shaped plate (250) covering said first conical shaped profile (215), and a second conical shaped plate (255) to cover said second conical shaped profile (220).
6. The exhaust emission system as claimed in claim 5, wherein said first conical shaped plate (250) comprises of a first set of opening (260) to enable a passage for atmospheric air to enter, and wherein said first set of openings is formed on said first conical shaped plate (250).
7. The exhaust emission system as claimed in claim 4, wherein said first curved surface (230) comprises of a second set of openings (265) formed therein enabling a passage for said atmospheric air to enter to optimize temperature of said muffler assembly (185).
8. The exhaust emission system as claimed in claim 5, wherein said second conical shaped profile (255) comprises of a third set of openings (270) formed therein.
9. The exhaust emission system as claimed in claim 4, wherein said first curved surface (230) and said second curved surface (235) are painted silver at inner surface to reflect heat being radiated from said muffler assembly (185).
10. The exhaust emission system as claimed in claim 4, wherein said first curved surface (230) and said second curved surface (235) are painted black at inner surface to absorb heat being radiated from said muffler assembly (185).
, Description:FIELD OF INVENTION
[0001] The present invention relates to an internal combustion engine and more particularly to an exhaust emission system for the internal combustion engine.
BACKGROUND OF INVENTION
[0002] 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 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 the muffler unit. A set of catalysts are provided either in the exhaust pipe or in the muffler unit, depending upon the vehicle, which oxidises the harmful gases. Conventionally, in two-wheeled motorcycles, muffler assemblies are 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 oxidize and convert harmful NOx to NO2 before entering into the atmosphere.
[0003] However, in high speed performance vehicles the combustion temperature is very high, due to which the paint applied of the muffler assembly tends to peel off easily. Thus, some of the vehicles use the muffler assembly in a discolored condition itself, hampering its aesthetic appeal. In furtherance to it, efficiency of the exhaust emission system for such high speed performance vehicles should be higher, which is not so in most of the known arts. The oxidation process of exhaust for such vehicles should be faster and much for effective. Hence, it is desired to have an improved design for the muffler assembly which enhances it aesthetic appeal. In furtherance to it, the efficiency of the exhaust emission system and oxidation process for exhaust being generated needs to be enhanced. Moreover, it is also desired to have an muffler assembly which solves the problem of discoloration and enhances the aesthetic appeal of the vehicle as well.
BRIEF DESCRIPTION OF DRAWINGS
[0004] 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.
[0005] Figure 1 illustrates a side view of an exemplary two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0006] Figure 2 illustrates a side view of an internal combustion connected to a muffler assembly in accordance with an embodiment of the present subject matter.
[0007] Figure 3 illustrates an exploded view of the muffler assembly connected to the internal combustion engine in accordance with an embodiment of the present subject matter.
[0008] Figure 4 illustrates an exploded view of a body guard with respect to the muffler assembly in accordance with an embodiment of the present subject matter.
[0009] Figure 5 illustrates an exploded view of the body guard depicting a plurality of openings formed in accordance with an embodiment of the present subject matter.
[00010] Figure 6 illustrates an exploded view of the body guard in accordance with an embodiment of the present subject matter.
[00011] Figure 7 illustrates a graph projecting time take for CAT light off in different muffler assemblies.

DETAILED DESCRIPTION
[00012] Generally, a saddle-type two or three-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. 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 an engine assembly mounted to it. The engine assembly is functionally connected to the rear wheel, which provides forward motion to the vehicle. A muffler assembly is provided at a lateral side of the vehicle 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 that covers various vehicle parts mounted thereon.
[00013] Typically, the internal combustion engine generates power by combustion an air-fuel mixture which it receives. After burning of the mixture, a substantial amount of exhaust in the form of harmful NOx and CO is generated. An exhaust port is provided on the internal combustion engine through which exhaust being generated leaves or exits. An exhaust pipe typically extends in a downward rearwardly fashion from the exhaust port through which the gases travel to reach the muffler unit. A set of catalysts are provided either in the exhaust pipe or in the muffler unit, depending upon the vehicle, which oxidises the harmful gases. Moreover, the muffler assembly is also used to dampen noise arising from the engine and prevent the harmful oxides from entering in the atmosphere. Furthermore, 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 oxidize and convert harmful NOx to NO2 before entering into the atmosphere.
[00014] However, in case of high speed and performance vehicles, the combustion temperature tends to be very high. The combustion temperature of such vehicles, typically ranges as high as 7000C, which is beyond the scope of most economical heat resistant coatings or paints generally applied on the muffler assembly of other vehicles. In such a case, paints/coatings applied on the muffler assembly peels off and results in discoloration of the muffler assembly. To avoid such a problem, some of the vehicles use a muffler assembly in a discolored state itself, but such a look has a negative effect on the aesthetic appeal of the vehicle & also leads to undesirable rust formation over a period of time leading to porosity, cracks etc.
[00015] Typically, the exhaust emission system of a high speed two-wheeled vehicle also faces performance issues with respect to high time taken for catalytic converter (hereinafter mentioned as CAT) light off. Generally, CAT light off means helping the CAT to achieve a substantial temperature at which it can enable the required oxidation and reduction process in a most effective manner without any adverse impact on the durability of the CAT. But, in case of high speed vehicles the time taken for complete exhaust emission process is very less, whereas the CAT light off time is high resulting in a delayed and insufficient oxidation process which affects the performance of the exhaust emissions system. In some of the previous known arts, an external source for enhancing the temperature for the catalytic converter was used. But, such provisions add to the extra combustion temperature and further degrade the discoloration effect explained above. Furthermore, in some of the known arts a muffler guard is provided for the muffler body, wherein the muffler guard also comprises of an opening to allow a flow of atmospheric air for cooling purposes. However, the efficiency for such openings has limited scope and for high end performance vehicles such openings are not capable of delivering the desired output.
[00016] Hence, an objective of the present subject matter is to provide an improved design for the muffler assembly which enhances the performance of the exhaust emission system by improving the CAT light off time & overcoming all problems in known art. In furtherance to it, the muffler assembly is provided with another configuration which helps in solving the discoloration issue and enhances the aesthetic appeal. According to one aspect of the present subject matter, a multi-purpose body guard is provided for the muffler assembly, which covers the entire muffler assembly. Such a body guard eliminates the need for dedicated coating/ painting for the muffler assembly, thereby preventing the discoloration of the muffler assembly, and such a body guard enhances the aesthetic appeal as well. Such a body guard of the present subject matter also reduces the manufacturing cost and servicing cost of the muffler assembly.
[00017] According to additional aspect, the body guard also traps the heat of the muffler assembly in that region which in turn results in faster CAT light off and enhances the performance of the exhaust emission system well. In furtherance to it, the body guard is provided with slots at both the ends which help in cooling and optimization of the muffler assembly temperature resulting in a better CAT light off. Dimension of such slots provided on the body guard depend on the vehicle specifications and requirements so that the muffler body temperature is maintained with respect to optimization of the time taken for CAT light off. The present subject matter can be used for two-wheeled, three-wheeled and four-wheeled vehicles as well, however for exemplary purpose it has been described with respect to a two-wheeled vehicle.
[00018] In an embodiment, 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. 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 an engine assembly mounted to it. The engine assembly is functionally connected to the rear wheel, which provides forward motion to the vehicle. A muffler assembly is provided at a lateral side of the vehicle 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 that covers various vehicle parts mounted thereon.
[00019] In an embodiment, the internal combustion engine 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 NOx and CO is generated. This harmful exhaust leaves the internal combustion engine from an exhaust port provided on the internal combustion engine. In an embodiment, an exhaust pipe extends in a downward rearwardly fashion, when seen from a side view of the vehicle, such that the gases travel from the exhaust port to reach the muffler unit. At least one or a set of catalysts are provides in the muffler assembly to oxidize and reduce the harmful gases. The muffler assembly is also provided to dampen noise arising from the engine and prevent the harmful oxides from entering in the atmosphere. The muffler assembly comprises of baffle pipes and chambers to increase the flow of the gas and dampen the sound coming from the engine. The muffler assembly also comprises of catalytic converters to oxidize and convert harmful exhaust emissions such as HC, CO & NOx before entering into the atmosphere.
[00020] In an embodiment, the exhaust pipe comprises of an upstream portion connected to the exhaust port from where it extends in a downward and rearward fashion to get connected to the muffler assembly. The muffler assembly is connected to the exhaust pipe at its rearmost portion, hereinafter mentioned as a downstream portion. In an embodiment, the muffler assembly is a substantial cylindrical shaped element with substantial conical shaped profile at both the ends. The muffler assembly comprises of a cylindrical shaped main body in which the catalysts and the baffle assemblies are disposed. A first conical shaped profile is formed on a front portion of the cylindrical shaped main body, wherein the exhaust pipe is connected to the muffler assembly through the first conical shaped profile. A second conical shaped profile is formed at a rear portion of the cylindrical shaped main body comprising of an opening through which the exhaust after reacting and oxidizing with the catalyst leaves the muffler assembly.
[00021] In an embodiment, the muffler assembly is not painted to meet the aesthetic requirement of the vehicle body, because of the discoloration which occurs due to the heat generated by the high speed engine. The muffler assembly is however covered by a multi-functional body guard, which covers the entire muffler assembly. In an embodiment, the muffler assembly is designed in such a way to match the aesthetic profile / feature of the vehicle and enhance it. Thus, the body guard eliminates the problem of discoloration and also enhances the aesthetic appeal of the vehicle.
[00022] In an embodiment, the body guard comprises of a first curved surface formed around the top portion of the main body of the muffler assembly to match its periphery, and a second curved surface formed around the bottom portion of the main body of the muffler assembly. The first curved surface and second curved surface combinedly, cover the entire main body of the muffler assembly. In furtherance to it, the body guard also includes a first conical shaped plate to be formed around the first conical shaped profile at a front portion of the main body near the downstream portion of the exhaust pipe. A second conical shaped plate is provided at the second conical shaped profile formed at the rear most portion of the main body. In an embodiment, the first curved surface, second curved surface, first conical shaped plate and second conical shaped plate combine to form the body guard to cover the entire muffler assembly to enhance the aesthetic appeal of the vehicle and eliminate any the problem of discoloration of the muffler assembly.
[00023] In an embodiment, the body guard covers the entire muffler assembly to enhance the aesthetic appeal and eliminate the problem of muffler discoloration, rusting etc, but it also traps the heat generated in the muffler assembly. The body guard does not allow the heat generated in the muffler assembly to radiate, rather it traps it around. The heat trapped by the body guard continuously builds up, such that the temperature around that region increases. The increasing temperature around the muffler assembly additionally heats up the CAT converter leading to an early CAT light off. Thus, the heat built up around the muffler assembly because of the body guard heats up the CAT converter also resulting in reduction of time taken for CAT light off. Therefore, the body guard of the present subject matter enhances the overall efficiency of the exhaust emission system by reducing the time taken for CAT light off.
[00024] In an embodiment, the body guard comprises of a plurality of slots formed in to provide a ventilation and passage for atmospheric air such that the temperature of the muffler body can be optimized. The plurality of slots is provided to allow a certain amount of atmospheric air to enter, so that the muffler assembly does not gets over heated. Overheating creates a safety hazard and is not good for CAT light off as well as its durability. Depending upon the vehicle capacity and requirement the geometry of the slots is varied to provide an entrance for the required amount of air to control the muffler body temperature. In an embodiment, the slots provide an entrance for air so that the muffler body is not excessively heated, and the temperature around that region is maintained to provide the required timing of the CAT light off, depending upon the vehicle and emission requirements. Thus, depending upon the vehicle requirement and specification the at least one or more slots provided on the surface of the body guard maintain the exact heat required in that region for an early CAT light off, and eliminate the possibility of more than required heat to build up in that region.
[00025] In an embodiment, a first set of slots is provided on a front portion of the body guard when seen from a front view of the vehicle, i.e. the first conical shaped plate. The present subject matter also comprises of a second set of slots provided on a top portion of the body guard, i.e. the first curved surface, and a third set of slots provided on a rear portion of the body guard when seen from a side, i.e. on the second conical shaped plate. A substantial amount of atmospheric air enters through the first set of slots provided on the first conical plate and leaves through the third set of slots provided on the second conical shaped plate. By providing first set of slots on the first conical shaped plate and third set of slots on the second conical shaped plate a proper channel of circulation and ventilation passage for atmospheric air is provided which has a much better cooling efficiency. In furtherance to it, the first set of slots is formed at an angel of not more than 45 degrees with respect to the direction of the atmospheric air. Thus, the angle of formation allows a maximum amount of atmospheric air to enter in allowing an enhanced cooling of the muffler assembly. Furthermore, the top and front portion of the muffler assembly are the most positive pressure coefficient areas, thus providing plurality of slots on the first conical plate and first curved surface has the most effective result increasing the cooling efficiency by a at least 5% over known arts. Thus, the plurality of slots is provided in a fashion to enhance the flow and circulation to have a better cooling efficiency, and also optimize the CAT light off.
[00026] In an embodiment, the body guard also retains and traps the heat radiated from the muffler assembly through convection, helping in artificially increasing the temperature of the muffler assembly. The heat rise can be precisely controlled by modifying the surface finish of the inner surface of the body guard to alter its radiation reflectiveness. In an embodiment, the surface finish of the inner surface of the body guard is painted black body to absorb the heat being generated by the muffler assembly in case when the temperature of the muffler assembly needs to kept in control, whereas in another embodiment, it is painted silver to further reflect the heat being generated in case when the temperature needs to be increased. Therefore, the present subject matter controls and alters the heat rise being radiated from the muffler assembly by modifying the surface finish of the inner surface of the full boy guard. As per an embodiment, a predetermined pattern & / or combination of black or silver or any other coatings may be incorporated to achieve intended amount of heat entrapment.
[00027] Thus, the present subject matter provides a multi-functional body guard for the muffler assembly which enhances the aesthetic appeal and eliminates the discoloration effect of the muffler assembly. The body guard described above provides an advantage of early CAT light off through convection resulting in enhancement in the efficiency of the exhaust emission system. In furtherance to it, the body guard comprises of slots which optimizes the muffle body temperature for an efficient CAT light off and prevents an over heating of the muffler assembly by providing an entrance for the atmospheric air. The inner surface of the body guard is accordingly modified to control the heat radiation reflectiveness.
[00028] 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.
[00029] 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.
[00030] Figure 1 illustrates a side view of an exemplary two-wheeled motor vehicle (100), in accordance with an embodiment of the present subject matter. The present subject matter is applicable for two-wheeled, three-wheeled and four-wheeled vehicles as well. Thus, hereinafter for the purposes of this invention the vehicle would be referred as multi-wheeled vehicle or just vehicle. The vehicle (100) includes a frame assembly (not shown) that extends from a head tube (not shown), which is disposed in the front portion of the vehicle (100), wherein said frame assembly extends towards a rear portion of the vehicle (100). The frame assembly (not shown) includes a mainframe (not shown) comprising a main tube extending rearward from a rear portion of the head tube and a down tube (not shown) that extends rearwardly downward from the head tube. The frame assembly (not shown) may further comprise a sub-frame formed by a pair of rear tubes (not shown) that extend obliquely rearward from the main frame. An engine assembly (110) is supported by the main frame of the frame assembly (not shown). The engine assembly (110) acts as the power unit of the vehicle (100), wherein the power unit may also include a traction/electrical motor (not shown). A front portion of a swing arm assembly (not shown) is swingably connected to the main frame of the frame assembly and rear portion of the swing arm assembly (not shown) rotatably supports a rear wheel (120). The rear wheel (120) is functionally coupled to the engine assembly (110) through a transmission system. A rear fender (not shown) disposed upwardly of the rear wheel (120) covers at least a portion of the rear wheel (120). Further, the swing arm assembly (not shown) is coupled to the frame assembly through one or more rear suspension(s). In the present embodiment, a rear suspension (115) connects the swing arm assembly (not shown) to the frame assembly. A muffler assembly (185) extends in a downward rearwardly fashion form the internal combustion engine (110), disposed on a lateral side of the vehicle (100) for a safe emission of exhaust to the atmosphere. A pair of front forks (130) supports a front wheel (135) and is steerably supported by the head pipe. A handlebar assembly (140) is connected to an upper portion of the pair of front fork (130). Further, a front fender assembly (145) covers at least a portion of the front wheel (135) and the front fender assembly (145) is mounted to the front forks (130).
[00031] A fuel tank (150) is mounted to the main tube of the frame assembly and disposed rearwardly of the handlebar assembly (140). A seat assembly (155) is disposed rearwardly of the fuel tank assembly (150) and supported by the pair of rear tubes. A foot rest sub-assembly (160) mounted to the frame assembly of the vehicle enable in supporting the rider foot and a side stand unit (175) is also mounted on the frame assembly used to support the vehicle during a parked condition. Further, the vehicle (100) comprises a headlamp assembly (165) that is disposed forwardly of the head tube. Also, the vehicle (100) may include a bottom cowl assembly (170) that covers at least a portion of the engine assembly (110) whereby the engine assembly (110) is protected from dust, dirt, and water splashing. The vehicle comprises of a pillion handle (180) that are disposed rearwardly of a side panel assembly and extend along the pair of rear tubes.
[00032] Figure 2 illustrates a side view of the internal combustion engine (110) connected to the muffler assembly of the exemplary vehicle (100) in accordance with an embodiment of the present subject matter. In an embodiment, the internal combustion engine (110) receives an air-fuel mixture which is burnt to provide the desired power for running of the vehicle (100). After the burning of the mixture, a certain amount of exhaust is produced in the internal combustion engine (110) which is sent out through an exhaust port (190) disposed on it. An exhaust pipe (195) is connected to the exhaust port (190) of the internal combustion engine (110) through which the exhaust travels to reach the muffler assembly (185). The muffler assembly (185) comprises of catalytic converters (not shown) and baffle assembly (not shown) which help in oxidizing of the exhaust gas, and helps in dampening the noise of the internal combustion engine (110). In an embodiment, the exhaust pipe (195) extends in a downward and rearward fashion from the exhaust port (190) to get connected to the muffler assembly (185). The exhaust pipe comprises of an upstream portion (200) which is connected to the exhaust port (190), and downstream portion (205) at which the muffler assembly (185) get connected to the exhaust pipe (195). The exhaust leaves the internal combustion engine (110) through the exhaust port (190) travelling through the exhaust pipe (195) to reach the muffler assembly (185) for further processes.
[00033] Figure 3 illustrates an exploded view of the muffler assembly (185) connected to the internal combustion engine (110) of the exemplary multi-wheeled vehicle (100) as shown in Fig. 1, in accordance with an embodiment of the present subject matter. In an embodiment, the exhaust travels along the exhaust pipe (195) to reach the muffler assembly (185). The muffler assembly (185) is a substantial cylindrical shaped element with conical shaped profile at both the ends. The muffler assembly (185) comprises of a cylindrical shaped main body (210), a first conical shaped profile (215) formed at the front portion of the main body (210) near the downstream portion (205) of the exhaust pipe (195) and a second conical shaped profile (220) formed at the rear most portion of the main body (210). In an embodiment, the entire muffler assembly (185) is covered by a multi-functional body guard (225) which eliminates the need of coloring the muffler assembly (185) and enhances the aesthetic appeal of the vehicle as well.
[00034] In an embodiment, the body guard (225) comprises of a first curved surface (230) and second curved surface (235). The first curved surface (230) covers a top portion of the main body (210) of the muffler assembly (185), whereas the second curved surfaced (235) covers a bottom portion of the main body (210) of the muffler assembly (185). The first curved surface (230) and the second curved surface (235) combined cover the entire cylindrical shaped main body (210) of the muffler assembly (185). In an embodiment, the body guard (225) also comprises of a first conical shaped plate (250) covering the first conical shaped profile (215) formed at the from portion of the main body (210), and a second conical shaped plate (255) covering the second conical shaped profile (220) formed at the rear portion of the main body (210). Thus, as per the present subject matter, the body guard (225) covers the entire muffler assembly (185) eliminating the need of coloring the muffler assembly, and in process solves the problem of discoloration of the muffler assembly (185), enhancing the aesthetic appeal of the vehicle (100) as well. In furtherance to it, the body guard (225) covering the muffler assembly (185) also traps the heat being generated from it, which provides extra heat for the catalytic converters and improves their light off time. Therefore, the body guard enhances the efficiency of the exhaust emission system as well. As per an aspect of the present subject matter, the body guard (225) is mounted on the muffler assembly (185) through suitable attaching means e.g. fasteners & mounting provision attached to the muffler body. The contact area of the attaching means as well as the contact between the muffler assembly (185) & the conical ends of the body guard (225) are very small. This enables configuring a body guard (225) substantially circumscribing the muffler assembly (185) in a pseudo hermetic condition wherein insignificant heat is transferred from the muffler assembly (185) to the body guard (225). Thus, even if any aesthetic coatings are provided on the guard (225), it does not get affected by the high temperature of the muffler assembly (185). In an embodiment, the body guard (225) can also be referred as a multi-functional pseudo hermetic body guard (225).
[00035] Figure 4 illustrates an exploded view of the body guard (225) along with the muffler assembly (185) of the exemplary multi-wheeled vehicle (100) in accordance with an embodiment of the present subject matter. In an embodiment, the body guard (225) comprises of first curved surface (230), second curved surface (235), first conical shaped plate (250) and the second conical shaped plate (255), wherein when all combined cover the entire muffler assembly (185). According to the present subject matter, the body guard (225) eliminates the need of coloring the muffler assembly (185) protecting it from the effect discoloration, rust and in process enhances the aesthetic appeal of the vehicle (100) as well. In furtherance to it, the body guard (225) traps the heat being radiated from the muffler assembly (185) in a running condition of the vehicle (100). This trapping of heat by the body guard (225) increases the temperature of the muffle assembly (185). As explained above, the muffler assembly (185) comprises of CAT converters which help in oxidization of the exhaust being sent from the internal combustion engine (110). However, there is a certain temperature up to which the CAT converter needs to be heated for its light off, so that it can be activated to react and oxidize the exhaust passing around it. The time taken to achieve the CAT light off explained above is high which results in a certain delay affecting the performance of the exhaust emission system. Thus, the body guard (225) explained above helps the CAT converter to achieve an early light off by trapping the heat being radiated thereby increasing the temperature around that region and that of the muffler assembly (185). However, depending upon the vehicle requirement the muffler assembly (185) should be heated to a certain range, and over heating should be avoided for an efficient CAT light off.
[00036] Hence, to optimize and regulate the temperature of the muffler assembly (185) a plurality of openings (260, 265, 270) is provided in the body guard (225). In an embodiment, the first conical shaped plate (250) comprises of a first set of openings (260), the first curved surface (230) comprises of a second set of slots (265) and the second conical shaped plate (255) comprises of a third set of slots (270). In an embodiment, the plurality of openings is also referred to as plurality of slots. Alternatively, the plurality of openings can also be called as plurality of ventilations. The plurality of openings (260, 265, 270) provide an entrance for the atmospheric air, which helps in optimization and controlling of the muffler assembly (185) temperature. Depending upon the vehicle requirement and specifications, the geometry of these openings are varied accordingly, so that the heat being trapped and temperature of the muffler assembly (185) can be optimized and controlled for an efficient CAT light off. Thus, as per the present subject matter the body guard (225) helps in trapping of the heat being radiated for an efficient and early CAT light off, and the plurality of slots (260, 265, 270) provided help in optimization of the muffler body (185) temperature.
[00037] Figure 5 illustrates an exploded view of the body guard (225) along with the muffler assembly (185) of the exemplary two-wheeled vehicle (100) in accordance with an embodiment of the present subject matter. In an embodiment, the plurality of slots comprises of the first set of slots (260), a second set of slots (265) and third set of slots (270) respectively. The first set of slots (260) is formed on the first conical shaped plate (250), the second set of slots (265) is formed on the first curved surface (230), whereas the third set of slots (270) is formed on the second conical shaped plate (255). The first set of slots (260) allows the atmospheric air to enter and leaves through the third set of slots (270) providing an enhanced circulation and ventilation of air flow which improves the cooling efficiency. In an embodiment, the first set of slots (260) is formed at an angle a with respect to the direction of atmospheric air entering, whereas the angle a being not more than 45 degrees. The first set of slots (260) is formed at such an angle on the first conical shaped plate (250) to allow the maximum amount of atmospheric to enter providing a maximum cooling efficiency. Furthermore, it is the top and front portion of the muffler assembly (185) which has the maximum positive pressure coefficient, thus providing atmospheric air on such areas would have the maximum cooling affect. Therefore, the first set of slots (260) is provided on the first conical shaped plate (250), and the second set of slots (265) is provided on the first curved surface (230) located on a front and top portion of the muffler assembly (185). By providing first set of slots (260) and second set of slots (265) at such a region enhances the cooling efficiency by at least 5%. Thus, providing the plurality of slots (260, 265, 270) enhances the cooling efficiency and helps in optimization of the CAT light off as well.
[00038] Figure 6 illustrates an exploded view of the body guard (225) of the muffler assembly (185) in accordance with an embodiment of the present subject matter. In an embodiment, the body guard (225) retains and traps the heat radiated from the muffler assembly (185) through convection, helping in artificially increasing the temperature of the muffler assembly (185). The heat rise can be precisely controlled by modifying the surface finish of the inner surface (275) of the body guard (225) to alter its radiation reflectiveness. In an embodiment, the surface finish of the inner surface (275) of the body guard (225) is painted black to absorb the heat being radiated from the muffler assembly (185) in case when the temperature needs to kept in control, whereas in another embodiment, it is painted silver to reflect heat being radiated in case when the temperature needs to be increased. Therefore, the present subject matter controls and alters the heat rise being radiated from the muffler assembly (185) by modifying the surface finish of the inner surface (275) of the full boy guard (225).
[00039] Figure 7 illustrates a graph projecting time taken for CAT light off for different muffler assemblies. As depicted by the graph time taken for 90 percent of CAT conversion for a muffler assembly without a body guard is almost 1.5 seconds. Whereas, for a muffler assembly provided with a body guard without any slots is 0.5 seconds. However, in such a scenario the muffler assembly becomes very hot and is not safe as well. Thus, as per the present subject matter, a muffler assembly with slots is provided for which time taken for at least 90 percent conversion of CAT lies in a range of 0.5-0.75 seconds. The graph illustrates the performance for different muffler assemblies, showing that the present subject matter is safe with the best possible output.
[00040] Thus, the present subject matter provides a body guard (225) used to cover the entire muffler assembly (185). The body guard (225) covers the entire muffler assembly (185) eliminating the need of painting and problem of discoloration of the muffler assembly (185) resulting in an enhanced aesthetic appeal of the vehicle (100). In furtherance to it, the body guard (225) traps the heat being radiated from the muffler assembly (185) to increase its temperature and the region surrounding it resulting in an early and efficient CAT light off. The body guard (225) is provided with a plurality of slots (260, 265, 270) which allows an entrance for atmospheric air for regulation and optimization of the muffler assembly (185) temperature to prevent it from extra heating.
[00041] 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.