DESC:TECHNICAL FIELD
[0001] The present subject matter relates generally to a two-wheeled motor vehicle, and more particularly to an exhaust unit for the two-wheeled motor vehicles.
BACKGROUND
[0002] Generally, in a two-wheeled saddle-ride type vehicle a frame assembly extends rearward from a head tube. The frame assembly acts as a skeleton for the vehicle that supports the vehicle parts. A front portion of the frame assembly connects to a front wheel through one or more front suspension(s). The frame assembly extends rearward of the vehicle, where a rear wheel is connected to a frame assembly through one or more rear suspension(s). An internal combustion (IC) engine is mounted to the frame assembly of the vehicle. The IC engine is functionally connected to the rear wheel, which provides the forward motion to the vehicle. Typically, plurality of panels is mounted to the frame assembly of the vehicle that covers various vehicle components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] 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.
[0004] Fig. 1 illustrates a right side view of an exemplary two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0005] Fig. 2 (a) illustrates a right side view of a frame assembly of a two-wheeled vehicle, in accordance with an embodiment of the present subject matter.
[0006] Fig. 2 (b) depicts a right side view of the exhaust unit and the muffler assembly connected thereof.
[0007] Fig. 2 (c) illustrates an enlarged right side view of the exhaust unit in accordance with the embodiment depicted in Fig. 2 (a).
[0008] Fig. 3 depicts a graph illustrating experimental graph for wheel force against engine speed, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[0009] Typically, in a two-wheeled saddle-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.
[00010] Generally, the exhaust system extends from the engine assembly towards a rear portion of the vehicle. The combusted air-fuel mixture, which are the exhaust gases are sent to atmosphere through a muffler. To meet with stringent emission norms, there is a need for ensuring that the exhaust gasses are purified before the gases are release into atmosphere. A catalytic converter disposed in the exhaust pipe enables in oxidation of un-burnt gases. Generally, a catalyst converter operates optimally in a specific temperature range. Therefore, the catalytic converter may be disposed in the exhaust pipe. However, back pressure is created in the exhaust pipe. Moreover, engine torque in low and mid range of the engine speed is also affected thereby affecting performance of the vehicle.
[00011] Hence, an objective of the present subject matter is to provide a two-wheeled vehicle employed with an exhaust unit. According to one aspect of the present subject matter, the exhaust unit enables in optimum functioning of a catalytic converter that is disposed in the exhaust unit. According to another aspect, the exhaust unit enables reduction of back pressure. Further aspect being, engine torque, in low and mid range of engine speed, is improved. Yet another aspect being, the present subject matter enables in overall noise reduction of the vehicle.
[00012] In an embodiment in accordance with the present subject matter, a two-wheeled vehicle employed with an exhaust unit is provided. An inlet of the exhaust unit is coupled to an engine assembly and an outlet of the exhaust unit is coupled to a muffler assembly. The exhaust unit and the muffler assembly are mounted to a frame assembly of the vehicle.
[00013] In an embodiment, the exhaust unit extends from an exhaust port of the engine assembly downwardly towards the muffler assembly of the vehicle. The muffler assembly is disposed adjacently to the rear wheel and extending substantially along longitudinal axis of the vehicle. In another embodiment, the muffler assembly may be disposed in line with a longitudinal axis of the vehicle or with an offset with the longitudinal axis of the vehicle.
[00014] In an embodiment, the exhaust unit is provided with at least one catalytic converter. In a preferred embodiment, the exhaust pipe is provided with a converter mounting portion that is adapted to accommodate the catalytic converter. Further, the exhaust unit is provided with a perforated tube.
[00015] In an embodiment, the exhaust pipe extends sidewardly downward from the exhaust port of the engine assembly. Further, the exhaust pipe extends rearwards from below the rider foot peg and substantially in longitudinal direction of the vehicle, towards the muffler assembly. In an embodiment, the catalytic converter is disposed in disposed forwardly of the rider foot peg. In a preferred embodiment, the converter mounting portion is integrally formed with the exhaust pipe. The perforated tube is disposed rearwardly of the catalytic converter. The perforated tube is disposed forwardly of the outlet portion of the exhaust pipe and rearwardly of the catalytic converter, therebetween, along the exhaust pipe.
[00016] In an embodiment, the perforated tube is disposed rearwardly of the catalytic converter and at a distance, in the range of one to five times of a diameter of the exhaust pipe, from the catalytic converter. In an embodiment, the perforated tube is disposed concentrically inside the exhaust pipe and end(s) of the perforated tube are supported by the exhaust pipe.
[00017] The present subject matter enables reduction of emissions and reduction of noise. Moreover, torque, which is essential parameter, is improved in low and mid range speed of the engine. Also, the exhaust unit is compact.
[00018] 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.
[00019] Fig. 1 (a) illustrates a right side view of an exemplary two-wheeled saddle-ride type vehicle, in accordance with an embodiment of present subject matter. The vehicle 100 has a frame assembly 105, which acts as the skeleton for bearing the loads. The frame assembly extends from a front portion F towards a rear portion R of the vehicle 100, which is substantially along a longitudinal axis of the vehicle 100. A handle bar assembly 110 is rotatably disposed through a head tube 105A (shown in Fig. 2) of the frame assembly 105. The handle bar assembly 110 is connected to a front wheel 115 through one or more front suspension(s) 120. A front fender 125 is mounted to the one or more front suspension(s) 120 and covers at least a portion of the front wheel 120. A swing arm 140 is swingably connected to the frame assembly 105. A rear wheel 130 is rotatably supported by the swing arm 140. A rear fender 135 is disposed upwardly of the rear wheel 130 and covers at least a portion of the rear wheel 130. One or more rear suspension(s) 140, which are connect the swing arm 140 to the frame assembly 105, that enable to sustain both radial and axial forces occurring due to rear wheel 130 reaction. A seat assembly 150 is mounted to the frame assembly 105. A fuel tank 155 is disposed at an anterior portion of the seat assembly 150.
[00020] An engine assembly 160 is disposed substantially below the fuel tank 155 and mounted to the front portion F of the frame assembly 105. The engine assembly 160 includes a starting mechanism, a transmission system for transferring the power to the rear wheel 130, and an air-fuel supply. Further, a carburetor or a fuel injection system or the like (not shown) supplies air-fuel mixture to the engine assembly 160. A muffler assembly 165 is mounted to the vehicle that transfers exhaust gases into atmosphere. An exhaust unit 200 is functionally coupled to the engine assembly 160 at one end and to the muffler assembly 165 on other end.
[00021] The handle bar assembly 110 includes a handle bar, an instrument cluster, handle grips and one or more levers. The vehicle 100 has various electrical loads including a headlamp 170, a tail lamp 175. Further, plurality of body panels including a pair of side panel(s) 180A and a tail cover-panel assembly 180B are mounted to the frame assembly 105 covering at least a portion of the frame assembly 105.
[00022] Fig. 2 (a) illustrates a right side view of an exemplary frame assembly 105 of a two-wheeled vehicle with parts laid thereon, in accordance with an embodiment of the present subject matter. The frame assembly 105 includes a head tube 105A, a main tube 105B extending rearward from the head tube 105A. The frame assembly 105 further comprises a down tube 105C extending obliquely downward from the head tube 105A. Also, one or more rear tubes 105D extend rearward from the main tube 105B towards a rear portion of the vehicle 100. In an embodiment, the one or more rear tubes 105D are supported by a secondary tube(s) 105E that extend inclinedly rearward from the main tube 105B.
[00023] The frame assembly 105 is provided with one or more engine mounting bracket(s) (not shown) for mounting the engine assembly 155 (shown in Fig. 1) to the frame assembly 105. The seat assembly 145 (as shown in Fig. 1) is mounted to the one or more rear tubes 105D of the frame assembly 105. The main tube 105B of the frame assembly 105 supports a pair of rider foot peg(s) 185 for resting rider foot. Further, the secondary frame 105E is mounted with a pillion foot bracket 195 and the pillion foot bracket 195 is provided with a pillion foot peg 195A for resting pillion foot. The rider foot peg 185 and the pillion foot peg 195A are made of a rigid material, for example any known metal, and are secured to the frame assembly 105. Further, an elastic material or the like may be provided on the rider foot peg 185 and the pillion foot peg 195A.
[00024] An exhaust pipe assembly 200 extends from an exhaust port (not shown) of the engine assembly 155 downwardly towards a muffler assembly 165 of the vehicle 100. The muffler assembly 165 is disposed adjacently to the rear wheel 130 and extending substantially along longitudinal axis of the vehicle 100. An inlet 205 of the exhaust pipe 210, which is disposed at one end, is functionally coupled to the engine assembly 155. Further, an outlet of the exhaust pipe 210 is coupled to the muffler assembly 165. The exhaust pipe is made of a rigid material, for example any known metal or the like.
[00025] The exhaust unit 200 is provided with at least one catalytic converter 215. In a preferred embodiment, the exhaust pipe 210 is provided with a converter-mounting portion 220 that is adapted to accommodate the catalytic converter 215. Further, the exhaust unit 200 is provided with a perforated tube 225. In addition, the exhaust unit 200 is provided with at least one exhaust mounting bracket(s) 210A that is affixed to the exhaust pipe 210. The exhaust unit 200 is secured to the frame assembly by mounting to the frame assembly 105 through said exhaust mounting bracket(s) 210A. Also, the muffler assembly 165 is provided with at least one muffler mounting bracket(s) 165A that is affixed to the muffler assembly 165. The muffler assembly is secured to the frame assembly 105 through the muffler mounting bracket(s) 165A. In addition, the exhaust unit 200 is supported by engine assembly 155 at one end and by the muffler assembly 165 at the other end.
[00026] The exhaust pipe 210 is provided with a bracket 190 welded thereon for mounting the exhaust pipe assembly 200 to the frame assembly 105. In a preferred embodiment, the bracket 190 is provided in vicinity to the perforated tube 225 to withhold the weight of the perforated tube 225 and the catalytic converter 215.
[00027] Fig. 2 (b) depicts a right side view of the exhaust unit 200 and the muffler assembly connected thereof. The exhaust pipe 210 of the exhaust unit 200 extends sidewardly downward from the inlet 205, which is coupled to the exhaust port of the engine assembly 155. Further, the exhaust pipe 210 extends rearwards from below the rider foot peg 185 and substantially in longitudinal direction of the vehicle 100 towards the muffler assembly 165. The muffler assembly 165 is disposed adjacently of the rear wheel 130, and substantially extends in the longitudinal direction of the vehicle 100. The exhaust pipe 210 is provided with the catalytic converter 215 that is disposed at the converter-mounting portion 220. In a preferred embodiment, the converter-mounting portion 220 is integrally formed with the exhaust pipe 210. The perforated tube 225 is disposed rearwardly of the catalytic converter 215. In other words, the perforated tube 225 is disposed downstream of the catalytic converter 215. Also, the perforated tube 225 is disposed forwardly or ahead of the outlet portion 230 of the exhaust pipe 210 and rearwardly of the catalytic converter 215, therebetween, with respect to direction of flow of exhaust gases in the exhaust pipe 210.
[00028] Further, the muffler assembly 165 is provided with one or more secondary perforated tubes 305A, 305B, and 305C that are disposed selectively in the muffler assembly 165. In an embodiment, at least one secondary pipe 305A is directly coupled to the exhaust pipe 210 of the exhaust unit 200. Also, the muffler assembly 165 includes a tail pipe through which exhaust gases enter atmosphere. In the present embodiment, the muffler assembly 165 has a circular cross-section. Also, the muffler assembly may have a cross-section with regular or irregular geometric shapes.
[00029] Fig. 2 (c) illustrates an enlarged right side view of the exhaust unit 200 in accordance with the embodiment depicted in Fig. 2 (a). The catalytic converter 215 is disposed in the exhaust pipe 210 of the exhaust unit 200. The perforated tube 215 is disposed rearwardly of the catalytic converter 215 and positioned forwardly of the outlet 230 of the exhaust pipe 210. In a preferred embodiment, the exhaust unit 200 is provided with the perforated tube 225 disposed at a distance X from the catalytic converter 215. The distance X is in the range of one to five times of a diameter D of the exhaust pipe 210. In an embodiment, the perforated tube 225 is disposed concentrically inside the exhaust pipe 210 and end(s) of the perforated tube 225 are supported by the exhaust pipe 210.
[00030] Further, the exhaust pipe 210 includes a first portion 210A and a second portion 210B composed integrally. The first portion 210A includes the upstream end portion 205 of the exhaust pipe 210 and extends inclinedly rearward towards the second portion 210B. The second portion 210B extends substantially horizontally in the longitudinal direction F-R of the vehicle 100. In one embodiment, the second portion 210B is having a length equal to or greater than the length of the first portion 210A. The second portion 210B is adapted to accommodate the at least one emission control device including catalytic converter 215 and the perforated tubes 225. In the present embodiment, the catalytic converter 215 is having a cylindrical cross section. The perforated tubes 225 is a cylindrical structure with plurality of apertures or holes provided on the circumference of the cylindrical structure. The catalytic converter 215 is disposed at the converter-mounting portion 220 having a cross sectional area greater than the cross-sectional area greater than the cross-sectional area of rest of the exhaust pipe 210. Also, in one embodiment, the perforated tube 225 is concentrically disposed about the exhaust pipe 210. In another embodiment, the perforated tube is disposed at an offset from the axis of the exhaust pipe 210.
[00031] Further, the converter-mounting portion 220 is disposed ahead and below to a rider footrest 185 whereby heat dissipated therefrom is directed away from the rider footrest 185.
[00032] Exhaust gases enter the exhaust pipe 210 through the inlet 205. The gases pass through the exhaust pipe 210 and reach the catalytic converter 215 that is disposed in the exhaust unit 200. The catalytic converter 215 operated optimally, as the gases, which are hot reach the catalytic converter 215. The gases are subject to oxidation. Further, the gases pass through the perforated tube 225 that is disposed rearwardly of the catalytic converter 215. The perforated tube 225 disposed in the exhaust unit 200 enables in reduction of back pressure and improves torque at low and mid range speed of the engine assembly 155. Further, the gases enter the muffler assembly 165, where the gases may be exposed to catalytic converters disposed therein. Also, the gases pass through the secondary perforated tubes 305A, 305B, and 305C provided in the muffler assembly 165 that enables in reduction of noise, thereby reducing noise of overall vehicle 100.
[00033] In one embodiment, the converter mounting portion 220 is provided with a cover member (not shown) covering at least a portion of the converter mounting portion 220. In a preferred embodiment, the cover member is covering at least a portion of the converter mounting portion 220 facing the rider foot rest 180A.
[00034] Fig. 3 depicts a graph illustrating experimental graph for wheel force against engine speed, in accordance with an embodiment of the present subject matter. A first curve A depicts a curve for wheel force, which is measured in Newton, against engine speed for a vehicle with a conventional exhaust unit. Further, a second curve B is a curve for wheel force against engine speed for the vehicle 100 employed with the exhaust unit assembly 200 in accordance with the present subject matter. The wheel force is analogous to the torque of the engine assembly 160. The vehicle 100 performance during initial engine speed, which is measured in rotations per minute (RPM) is imperative. The present subject matter provides the low speed or low RPM performance of the engine is improved as the back pressure affecting the engine performance is optimized. Therefore, in the low speed, performance of the engine is improved thereby providing improved pickup. Also, in the mid range of the engine speed the performance of the vehicle is also improved. As, the vehicle is generally operated in the mid range, the exhaust unit assembly 200 enables improved performance in the mid range. The exhaust unit 200 enables reduction of back pressure, thereby improving torque in range RI including low and mid range of engine speed.
[00035] 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:I/We claim:
1. An exhaust unit assembly (200) for a two-wheeled vehicle (100), said exhaust unit assembly (200) is functionally connected to an engine assembly (160) for directing exhaust gases from said engine assembly (300) to a muffler assembly (165), said exhaust unit assembly (200) comprising:
an exhaust pipe (210) comprising an upstream end portion (205) and a downstream portion (230), said upstream end portion (205) functionally connected to said engine assembly (160) and said downstream end portion (230) functionally connected to said muffler assembly (165); and
at least one catalytic converter (215) disposed in said exhaust pipe (210) away from said upstream end portion (205),
wherein
said exhaust pipe (210) is provided with at least one perforated tube (225) disposed downstream to said at least one catalytic converter (215) and ahead of said downstream end portion (230), therebetween, with respect to a direction of flow of said exhaust gases.
2. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein, said perforated tube (225) is disposed from said at least one catalytic converter (215) at a distance (X) equal to at least a diameter (D) of said exhaust pipe (210).
3. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said perforated tube (225) is disposed from said at least one catalytic converter (215) at a distance (X) equal to five times or less of a diameter (D) of said exhaust pipe (210).
4. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said exhaust pipe (210) includes a second portion (210B) extending substantially horizontally in a longitudinal direction (F-R) of the vehicle, and said at least one catalytic converter (215) and said perforated tube (225) are disposed about said second portion (210B).
5. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said exhaust pipe (210) is provided with a bracket (190) thereon disposed in vicinity to at least one of said perforated tube (225) and the at least one catalytic converter (220).
6. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said at least one catalytic converter (215) is disposed about a converter mounting portion (220), wherein said converter mounting portion (220) is having a cross-sectional area greater than the cross-sectional area of the exhaust pipe (210).
7. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1 or 6, wherein said converter mounting portion (220) is provided with a cover member covering at least a portion of said converter mounting portion (220).
8. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said wherein said downstream end portion (230) of said exhaust pipe assembly (200) is connected to said muffler assembly (300) enclosing one or more perforated tubes (305A, 305B, 305C) disposed therein.
9. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said engine assembly (160) is a forwardly inclined and four-stroke type.
10. The exhaust unit assembly (200) for the two-wheeled vehicle (100) of claim 1, wherein said downstream end portion (230) of said exhaust pipe (210) extends rearward in longitudinal direction (F-R) beyond a main tube (105B) of said frame assembly (105).