DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to an internal combustion engine, and more particularly to an exhaust emission system for said internal combustion engine.
BACKGROUND
[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 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 unit. A set of catalysts are provided either in the exhaust pipe or in the muffler unit, depending upon the vehicle, which oxides 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 unit 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 entering into the atmosphere.
[0003] With emissions norms becoming stringent the efficiency of the exhaust emission system is something which has become one of the most critical aspects. Different set ups and systems have been designed to improve the efficiency of the exhaust emission system and the catalytic converter in particular. Some of these systems implement a use of more than one catalytic converter. In some of the other known arts, the location and material of the catalytic converters becomes important and is changed to achieve a better result. However, using such an arrangement makes the system costly and heavy. Furthermore, it also happens that in such an arrangement the expected efficiency is not achieved and the catalytic converters remain underutilized.
[0004] Thus, it has been observed that even after implementing these systems the catalytic converter is not used to its optimum potential as the toxic gases emitted are not diffused properly and the uniformity index is low. Hence, even after implementation of such system the flow and distribution of the exhaust is not uniform due to which the catalytic converter implemented is not used to its full potential.
[0005] Thus the present invention provides an exhaust emission system with a better efficiency result, wherein there is no requirement of any extra catalytic converter. Furthermore, the present subject matter ensures a better result and a full utilization of the catalytic converter. In addition to it, the present subject ensures a lower manufacturing cost, without making the system heavy and bulky.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The detailed description of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.
[0007] Fig. 1 illustrates a side view of an exemplary two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0008] Fig. 2 illustrates a perspective view of an exhaust emission system provided for the exemplary two-wheeled vehicle as shown in Fig. 1, in accordance with an embodiment of the present subject matter.
[0009] Fig. 3 illustrates a perspective view of an exhaust pipe of the exhaust emission system as shown in Fig. 2, in accordance with an embodiment of the present subject matter.
[00010] Fig. 4 illustrates a cross-sectional view of the exhaust emission system in accordance with an embodiment of the present subject matter.
[00011] Fig. 5 illustrates a cross-sectional view of a pre-adapter accommodated in the exhaust emission system in accordance with an embodiment of the present subject matter.
[00012] Fig. 6 illustrates a cross-sectional view of a pre-adapter accommodated in the exhaust emission system in accordance with an embodiment of the present subject matter.
[00013] Fig. 7 illustrates a prior art for the exhaust emission system.
[00014] Fig. 7(a) illustrates a perspective view of the working of the exhaust emission system in accordance with an embodiment of the present subject matter.
DETALIED DESCRIPTION
[00015] 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. 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 internal combustion engine mounted to it. Generally, the internal combustion engine is functionally connected to the rear wheel, which provides forward motion to the vehicle. A muffler unit is provided at a lateral side of the vehicle, wherein said muffler unit is mounted to the frame assembly or the vehicle through a mounting bracket.
[00016] 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. 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 liner motion is converted to a rotational motion of a crankshaft, which is finally transferred to the rear wheel.
[00017] Typically, an exhaust emission system of the two-wheeled vehicle extends in a downward manner from the internal combustion engine, further extending towards a rear portion of the vehicle. The unburnt air-fuel mixture in form of exhaust gases is emitted in 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 unit, to enable oxidation of the unburnt gases such that the toxic gases are converted to less harmful gases. The muffler unit is also meant for achieving overall noise reduction.
[00018] To achieve a better efficiency, some of the known exhaust emission systems have come up with various measures generally pertaining to their catalytic converter. Some of these known exhaust emission system includes more than one catalytic converter to come up with a better reaction rate. Whereas some of the known exhaust emission systems have the location of the catalytic converter to be changed to provide better interface and contact with the toxic gases. Some of such known exhaust emission systems also concentrate upon the material composition of the catalytic converter, and try changing its Nobel element composition to achieve a better reaction and performance.
[00019] However, even after implementing changes in its catalytic converter, such systems still face challenges with respect to its efficiency. There also exists a problem of utilization of the catalytic converter to its optimum potential. It has been observed that the catalyst converter is not utilized to its optimum potential. The toxic gases which enter the system do not diffuse properly and the uniformity index is low. Moreover, toxic gases which are emitted from the internal combustion engine pass through the muffler unit and hit the catalytic converter at a concentrated spot. This results in larger part of surface area of the catalytic converter being unused. If the whole or a large part of the surface area of the catalytic converter is successfully utilized for conversion and oxidation/reduction reaction, the performance of the exhaust emission system would automatically increase. Therefore, if the above cited issue is addressed the performance of the exhaust emission system would enhance without implementation of any extra catalytic converter, or any other element as a matter of fact.
[00020] The present subject matter overcomes the above stated problems of the exhaust emission system known in the prior art. One of the objectives of the present subject matter is to provide a two-wheeled or three-wheeled vehicle employed with an exhaust emission system with an enhanced performance. Furthermore, the present subject matter provides an exhaust emission system which tries to achieve the optimum potential of the catalytic converter. In an embodiment, yet another objective of the present subject matter is to allow a better interaction and reaction of the unburnt gases and exhaust emission with the catalytic converter, such that the whole or a large part of the surface area of the catalytic converter is utilized. In addition to it, the present subject matter enables in overall reduction of manufacturing cost.
[00021] In an embodiment in accordance with the present subject matter, a two-wheeled vehicle employed with an exhaust emission system is provided. The exhaust emission system comprises of an exhaust pipe extending from an exhaust port provided on the internal combustion engine. The exhaust pipe extends in a downward and rearward manner when seen from a front view of the vehicle. In an embodiment, the exhaust pipe comprises of an upstream portion being connected to the exhaust port, and a downstream portion formed at its extreme end opposite to that of the upstream portion.
[00022] In an embodiment, exhaust being generated in the internal combustion engine enters the exhaust emission system through the upstream portion of the exhaust pipe. The downstream portion of the exhaust pipe is connected to a pre-adapter, wherein an adapter is connected to the other end of the pre-adapter. In an embodiment, the exhaust emission system comprises of a muffler unit welded onto said adapter, wherein said muffler unit comprises of a catalytic converted disposed in it for an oxidation and reduction reaction with the exhaust gases. In an embodiment, one end of the adapter is connected to the pre-adapter, wherein the other end is connected to the catalytic converter and the muffler unit is welded on the outer surface of the adapter. In an embodiment, such an assembly and arrangement is provided such that the exhaust enters the exhaust emission system through the upstream portion of the exhaust pipe and flows through it to enter the pre-adapter from where the exhaust flows to hit the catalytic converter disposed at the other end of the adapter.
[00023] In an embodiment, the exhaust pipe comprises of a flaring portion formed at it downstream portion, wherein the exhaust pipe is connected to the pre-adapter through the flaring portion formed at the downstream portion. As per the present subject matter, the faring portion extends coaxially outwards from the exhaust pipe at an angle of not more than 15 degrees with respect to it. In an embodiment, the flaring portion extends rearwardly upwards configured for a coaxial attachment to the pre-adapter, wherein the diameter of the pre-adapter is not more than two times as that of the diameter of the exhaust pipe. In an embodiment, the pre-adapter comprises of a first end connected to the flaring portion of the exhaust pipe and a second end connected to the adapter, wherein the outer surface of the adapter also extends coaxially outwards an angle of not more than 18 degrees. Furthermore, the adapter comprises of a front end formed towards the front wheel of the vehicle, and a rear end formed towards the rear wheel of the vehicle. In an embodiment, the front end of the adapter is connected to the pre-adapter and the rear end is connected to the catalytic converter disposed in the muffler unit. The muffler unit is adapted on the outer surface of the adapter. Hence, exhaust travels through the exhaust pipe and enters the pre-adapter after passing through the flaring portion, after which it flows through the adapter to hit and react with the catalytic converter.
[00024] The present subject matter increases the performance of the exhaust emission system by improving the oxidation and reaction of the toxic gases. In an embodiment, the present subject matter improves the diffusion rate of the toxic gases and increases the uniformity index by 23%. In an embodiment, the present subject matter successfully uses the catalytic converter to its optimum potential by using a substantial part of the surface area of the catalytic converter. The flaring portion at the downstream portion of the exhaust pipe, coupled with the pre-adapter and the adapter are provided in series so that the emission coming out of the engine assembly reacts with a larger surface area of the catalytic converter and not just hit and react at a certain concentrated spot. In addition to it the present subject matter also helps in reduction of the manufacturing cost.
[00025] 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.
[00026] 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.
[00027] Fig. 1 illustrates a side view of an exemplary two-wheeled vehicle (50), in accordance with an embodiment of the present subject matter. The vehicle (50) includes a frame assembly (5) that extends from a head tube (not shown), which is disposed in the front portion of the vehicle (50). The frame assembly (5) 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 (5) may further comprise a sub-frame formed by a pair of rear tubes (not shown) that extend obliquely rearward from the main frame. An internal combustion engine (4) is supported by the main frame of the frame assembly (5). The internal combustion engine (4) acts as the power unit of the vehicle (50), wherein the power unit may also include a traction/electrical motor (not shown). A front portion of a swing arm assembly (15) is swingably connected to the main frame of the frame assembly (5) and rear portion of the swing arm assembly (15) rotatably supports a rear wheel (11). The rear wheel (11) is functionally coupled to the engine assembly (4) through a transmission system. A rear fender (14) disposed upwardly of the rear wheel (11) covers at least a portion of the rear wheel (11). Further, the swing arm assembly (15) is coupled to the frame assembly (5) through one or more rear suspension(s). A pair of front forks (8) supports a front wheel (10) and is steerably supported by the head pipe. A handlebar assembly (2) is connected to an upper portion of the pair of front fork (8). Further, a front fender assembly (9) covers at least a portion of the front wheel (10) and the front fender assembly (9) is mounted to the front forks (8).
[00028] A fuel tank (3) is mounted to the main tube of the frame assembly (5) and disposed rearwardly of the handlebar assembly (2). A seat assembly (12) is disposed rearwardly of the fuel tank assembly (3) and supported by the pair of rear tubes. Further, the vehicle (50) comprises a visor assembly (6) that is disposed forwardly over the headlamp (7). A tail cover assembly (16) is disposed rearwardly of the side panel assembly (not shown) and extends along the pair of rear tubes thereby covering at least a portion of the pair of rear tubes. The tail cover assembly (16) extends towards a rear portion of the frame assembly (5) and the tail cover assembly (16) is adapted to accommodate a pillion handle (13) attached to its side. An exhaust emission system (100) is disposed extending substantially rearwardly upward from an exhaust pipe of the engine assembly (4).
[00029] Fig. 2 illustrates a perspective view of the exhaust emission system (100) of the two-wheeled motor vehicle (50) shown in Fig. 1, in accordance with an embodiment of the present subject matter. In an embodiment, the exhaust emission system (100) comprises of an exhaust pipe (101) extending in a downward and rearward fashion from the internal combustion engine (4). In an embodiment, the exhaust pipe (101) comprises of an upstream portion (107) which is connected to the internal combustion engine (4) and through which the exhaust enters the exhaust pipe (101). Furthermore, the exhaust pipe (101) comprises of a downstream portion (108) formed at an extreme end of the exhaust pipe (101), opposite to that of the upstream portion (107). The downstream portion (108) of the exhaust pipe (101) is connected to a pre-adapter (103). In an embodiment, the exhaust pipe (101) comprises of a flaring portion (102) formed at the downstream portion (108), wherein said flaring portion (102) extends co-axially outwards and upwards to get connected to the pre-adapter (103). Thus, it is the flaring portion (102) formed at the downstream portion (108) through which the exhaust pipe is connected to the pre-adapter (103). In an embodiment, the pre-adapter (103) is further connected to an adapter (104). Therefore, the pre-adapter (103) maintains the connection between the exhaust pipe (101) and adapter (104), such that the exhaust travelling through the exhaust pipe (101) flows through the pre-adapter (103) and adapter (104) to get in contact with a catalytic converter (105) attached to the other end of the adapter (104), wherein said catalytic converter (105) is disposed in a muffler unit (106).
[00030] Fig. 3 illustrates a perspective view of the exhaust pipe (101) in accordance with an embodiment of the present subject matter. As explained above, the exhaust pipe (101) comprises of an upstream portion (107) formed at a front portion of the exhaust pipe (101) when seen from a front view of the vehicle (50), wherein the exhaust pipe (101) is connected to the internal combustion engine (4) through it. The downstream portion (108) is formed at the other end of the exhaust pipe (101), opposite to that of the upstream portion (107). As per the present subject matter, the flaring portion (102) is formed at the downstream portion (108) of the exhaust pipe (101). In an embodiment, the flaring portion (102) extends in a coaxially outwards and upward direction from the exhaust pipe (101) at a pre-determined angel a. As per the present subject matter, the pre-determined angle a at which the flaring portion (102) extends outwards is not more than 15 degrees. Furthermore, the exhaust pipe (101) through which exhaust travels comprises of a diameter D.
[00031] Fig. 4 illustrates a cross-sectional view of the exhaust emission system (100) in accordance with an embodiment of the present subject matter. As explained above, the exhaust pipe (101) comprises of a flaring portion (102) formed at its downstream portion (108). The exhaust pipe (101) is connected to the pre-adapter (103) through the flaring portion (102) extending coaxially outwards at a pre-determined angle a. The pre-adapter (103) enables a secure connection between the exhaust pipe (101) and adapter (104) enabling a passage for the exhaust to flow from the exhaust pipe (101) to the adapter (104). In an embodiment, the pre-adapter comprises of a diameter D1, wherein as per the present subject matter the value of D1 is not more than twice of D (diameter of exhaust pipe). The adapter (104) is connected to the other end of the pre-adapter (103), wherein the outer surface of the adapter (104) extends in a coaxial outward direction at a pre-determined angle ß, when seen from a front view of the vehicle (50). In an embodiment, the pre-determined angle ß at which the outer surface of the adapter (104) extends coaxially outwards is not more than 18 degrees. The other end of the adapter (104) is connected to the catalytic converter (105), and the muffler unit (106) is welded on the outer surface of the adapter (104). Thus, the present subject matter through the current assembly and dimensions allows a better diffusion for the exhaust travelling to react with the catalytic converter (105). In addition to it, it improves the uniformity index of the exhaust travelling and enhances the reaction rate of the exhaust with the catalytic converter (105) by enabling the exhaust to get in contact with a larger surface area of the catalytic converter (105).
[00032] Fig. 5 illustrates a cross-sectional view of the pre-adapter (103) in accordance with an embodiment of the present subject matter. In an embodiment, the pre-adapter (103) helps in co-axial attachment of the exhaust pipe (101) to the adapter (104) through its first end (103F) and second end (103S). In an embodiment, the first end (103F) of the pre-adapter (103F) is connected to the flaring portion (102) of the exhaust pipe (101) formed at its downstream portion (108), whereas the second end (103S) of the pre-adapter (103) is connected to the adapter (104). Thus, though the present construction the pre-adapter (103) ensure a stable connection between exhaust pipe (101) and adapter (104) allowing the exhaust to flow and react with the catalytic converter (105). Furthermore, the pre-adapter (103) is structured comprising of a diameter D1 which is almost two times of that of the diameter D of the exhaust pipe (101).
[00033] Fig. 6 illustrates a cross-sectional view of the adapter (104) in accordance with an embodiment of the present subject matter. In an embodiment, the adapter (104) comprises of a front end (104F) formed in the direction of the front end of the vehicle (50), and a read end (104R) formed towards a rear end of the vehicle (50). The front end (104F) of the adapter (104) is connected to the pre-adapter (103), and the catalytic converter (105) is attached on the rear end (104R) of the adapter. As per the present subject matter, the outer surface of the adapter (104) extends coaxially outwards at a pre-determined angle ß, wherein the value of ß is not more than 18 degrees. The adapter (104) ensures and allows a passage for the exhaust travelling through the exhaust pipe (101) and pre-adapter (103) to flow and react with the catalytic converter attached at its rear end (104R). In addition to it, the adapter (104) comprises of an outer surface (104S) to which the muffler unit (106) is welded.
[00034] Fig. 7 illustrates a prior art for an exhaust emission system. The figure depicting the prior art shows the direction taken by the exhaust (70) while travelling through the exhaust emission system. According to the previous known arts, the diffusion rate and uniformity index of the exhaust (70) travelling and reacting with the catalytic converter was very low. Thus, the expected efficiency was never achieved. Hence, different exhaust emission systems tried using multiple numbers of catalytic converters at different locations. But, this only added to the manufacturing cost and made the system heavier. In addition to it, the catalytic converter used in prior art was never fully utilized and used to its optimal level. The exhaust (70) reacting with the catalytic converter would only hit at a concentrated spot and rest of the surface area of the catalytic converter remained unutilized. Thus, these are the problems which the present subject matter solved.
[00035] Fig. 7(a) illustrates a perspective view of the working of the exhaust emission system (100) in accordance with an embodiment of the present subject matter. As per the present subject matter, the flaring (102), pre-adapter (103) and adapter (104) are connected in series with its construction as specified above. The profile of the present system is a continuous increasing one formed around specific pre-determined angles and dimensions to achieve the original intended objective. The present figure illustrates the exhaust flow (71) as the present subject matter. As illustrated, the present subject matter with its specific construction allows sufficient profile and space for the exhaust (71) to flow, which results in a better diffusion rate and uniformity index. The present construction helps in improvement of the uniformity index of the exhaust by almost 23%. In furtherance to it, the present subject matter also enables an optimal utilization of the catalytic converter. In accordance with the present subject matter, exhaust (71) is not concentrated at one single spot on the catalytic converter (105), and a substantial part of its surface is utilized resulting in a better reaction rate. Thus, the present subject matter improves the efficiency of the exhaust emission system (100) without making it heavy and complex or increasing the manufacturing cost.
[00036] 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.
,CLAIMS:We Claim:
1. An exhaust emission system (100) for an internal combustion engine (4) of a vehicle (50), wherein said exhaust emission system (100) comprises:
a muffler unit (106) comprising a catalytic converter (105) disposed therein for oxidation and reduction of exhaust being produced from said internal combustion engine (110);
an adapter (104) comprising an outer surface (104S) over said muffler unit (106) is welded;
an exhaust pipe (101) comprising an upstream portion (107) being connected to said internal combustion engine (4) and a downstream portion (108) formed on an opposite end as that of said upstream portion (107), wherein said exhaust pipe (101) comprises a coaxially outward extending flaring portion (102) formed at said downstream portion (108), and said flaring portion (102) extends outwards at a pre-determined angle, being connected to a pre-adapter (103).
2. The exhaust emission system (100) as claimed in claim 1, wherein said flaring portion (102) extends coaxially outwards in an upward direction at a pre-determined angle of not more than 15 degrees with respect to said exhaust pipe (101).
3. The exhaust emission system (100) as claimed in claim 1, wherein said exhaust pipe (101) comprising of a diameter D is connected to said pre-adapter (103) through said flaring portion (102) formed at said downstream portion (108).
4. The exhaust emission system (100) as claimed in claim 1, wherein said pre-adapter (103) comprises of a diameter D1 of not more than twice of diameter D of said exhaust pipe (101).
5. The exhaust emission system (100) as claimed in claim 1, wherein said pre-adapter (103) is disposed between said flaring portion (102) formed at said downstream portion (108) of said exhaust pipe (101) and said adapter (104).
6. The exhaust emission system (100) as claimed in claim 1, wherein said pre-adapter (103) comprises of a first end (103F) formed at front portion therein when seen from a front view of said vehicle (50), and a second end (103S) formed at a rear portion therein when seen from a front view of said vehicle (50).
7. The exhaust emission system (100) as claimed in claim 1, wherein said pre-adapter (103) is connected to said flaring portion (102) through said first end (103F) formed therein.
8. The exhaust emission system (100) as claimed in claim 1, wherein said pre-adapter (103) is connected to said adapter through said second end (103S) formed therein.
9. The exhaust emission system (100) as claimed in claim 1, wherein said adapter (104) connected to said pre-adapter (103) extends coaxially outwards at a pre-determined angle of not more than 18 degrees with respect to said pre-adapter (103).
10. The exhaust emission system (100) as claimed in claim 1, wherein said exhaust pipe (101) comprising of said flaring potion (102), said pre-adapter (103) and said adapter (104) are connected in series.