WO2020174484A1

WO2020174484A1 - A discharge system and motor vehicle thereof

Info

Publication number: WO2020174484A1
Application number: PCT/IN2019/050923
Authority: WO
Inventors: Bharaniram Senthilkumar; Boobalan Mani; Gundavarapu V S KUMAR; Vethanayagam Jayajothi Johnson
Original assignee: Tvs Motor Company Limited
Priority date: 2019-02-27
Filing date: 2019-12-16
Publication date: 2020-09-03
Also published as: CN113383151A; MX2021009890A; EP3931428A1; BR112021016709A2; EP3931428A4

Abstract

The present subject matter relates to a discharge system for a motor vehicle. A discharge pipe (205) of the discharge system formed by a first portion (206) and a second portion (207). The first portion (206) includes a first-upstream end portion (208) connected to an exhaust port (184). The second portion (207) is disposed downstream of the first portion (206), and the second portion (207) includes a second-upstream end portion (215). One of first portion (206) and second portion (207) is adapted to support at least a portion of a treatment device (211). The first portion (206) is capable of at least partially annularly enclosing the treatment device (211). The discharge pipe (205) is optimally provided with minimal parts and joints, and at the same time offers quick heating of the treatment device (211).

Description

A DISCHARGE SYSTEM AND A MOTOR VEHICLE

THEREOF

TECHNICAL FIELD

[0001] The present subject matter, in general, relates to a motor vehicle including an internal combustion engine and, in particular relates to a combustion gas- discharge system for the internal combustion engine of the motor vehicle.

BACKGROUND

[0002] Generally, motor vehicles like saddle -ride type vehicles which are compact are provided with an internal combustion (IC) engine unit. These saddle- ride type vehicles have gained popularity due to their compact layout and their ability to carry an additional passenger and/or to carry loads on them. These vehicles may constitute two-wheels or three-wheels depending on application, engine layout etc. Some of these vehicles are provided with a swinging-type engine, and a connecting link like a toggle link is provided to swingably support the IC engine unit. Some other type of saddle-ride type vehicle have the IC engine fixedly mounted to the frame. In these vehicles the IC engine may be forwardly inclined. Thus, these vehicles have a discharge system that is extending at a lower portion of the vehicle and extending towards a muffler positioned on one of the sides of the vehicle or may be at a center. Thus, the vehicle is to be provided with sufficient ground clearance to securely accommodate the discharge system, which is one of many packaging & layout challenges in such vehicles.

[0003] Additionally, these saddle ride-type motor vehicles are operated in different terrains and with different driving patterns as those are dependent on the location of operation or user, which are beyond control of the manufacturer. These vehicles when operated in such different terrains and with different driving patterns are subjected to jerks and the resultant impact may be transferred to various systems of the vehicle.

[0004] Moreover, when the swinging-type IC engine is provided, it is directly subjected to such jerks due to connection with at least one wheel of the vehicle, which is subjected to swinging motion. The discharge system directly connected to the IC engine directly receives such impacts from the IC engine. Thus, the discharge system requires a rigid mounting.

[0005] In addition, inherently the motor vehicle may have vibrations due to the presence of the IC engine that is operated across wide range of engine rotations per minute (RPM) causing vibrations that creep to other parts of the vehicle. The various system mounted on the vehicle especially the discharge system is to be securely accommodated on the motor vehicle and should be able to perform optimally without failure even when the vehicle is subject to such jerks or vibrations.

[0006] Moreover, the discharge system has to perform optimally in order to treat exhaust gases without any failure of the system even under severe usage conditions. For example, a poor ground clearance may damage the discharge system, which is substantially at a lower portion on the vehicle resulting in affecting the performance of the discharge system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The detailed description is described with reference to the accompanying figures. The same numbers are used throughout the drawings to reference like features and components.

[0008] Fig. 1 depicts a right side view of an exemplary motor vehicle, in accordance with an embodiment of the present subject matter.

[0009] Fig. 2 illustrates a front perspective view of the power unit, in accordance with the embodiment as depicted in Fig. 1.

[00010] Fig. 3 depicts a right side perspective view of a discharge system, in accordance with the embodiment of Fig. 2.

[00011] Fig. 4 depicts an exploded view of a portion of the discharge system, in accordance with the embodiment as depicted in Fig. 3.

[00012] Fig. 5 depicts a detailed view of the discharge pipe, in accordance with an embodiment of the present subject matter.

[00013] Fig. 6 depicts another detailed view of a portion of the discharge pipe, in accordance with an embodiment of the present subject matter. [00014] Fig. 7 (a) depicts a sectional view of the discharge pipe taken at axis A- A’, in accordance with another embodiment of the present subject matter.

[00015] Fig. 7 (b) depicts another sectional view of the discharge pipe taken at axis B-B’, in accordance with another embodiment of the present subject matter as depicted in Fig. 7 (a).

[00016] Fig. 7 (c) depicts another sectional view of the discharge pipe taken at axis C-C’, in accordance with another embodiment of the present subject matter as depicted in Fig. 7 (a).

[00017] Fig. 8 depicts graphical representation of conversion efficiency of treatment device versus time.

[00018] Fig. 9 depicts a sectional view of a discharge system taken along axis X- X’, in accordance with an embodiment of the present subject matter.

[00019] Fig. 10 (a) depicts a sectional view of an implementation of the discharge system taken along axis Y-Y’, in accordance with an embodiment of the present subject matter.

[00020] Fig. 10 (b) depicts another sectional view of another implementation of the discharge system, in accordance with an embodiment of the present subject matter.

[00021] Fig. 11 depicts a sectional view of the discharge, in accordance with yet another embodiment of the present subject matter.

[00022] Fig. 12 depicts an exploded view of the discharge, in accordance with the embodiment of Fig. 11.

[00023] Fig. 13 depicts a graphical representation of uniformity index against various flow rates.

DETAILED DESCRIPTION

[00024] Conventionally, motor vehicles are provided with drive means including the internal combustion (IC) engine and/or a traction motor. Also, the vehicle includes various sub-systems like the air induction system that works in conjunction with the fuel supply system like carburetor or fuel injector. Air-fuel mixture is supplied to the IC engine for combustion, which produces desired power and torque that is transferred to at least one wheel of the vehicle. Further, the gas discharge system includes discharge pipe that transmits the gases generated during combustion process to a muffler. Generally, the gases that are produced may include various harmful components including total hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx). There is a need for treating the harmful components prior to emitting the gases into the atmosphere through the muffler. Typically, a gas treatment device is used for treatment of the aforementioned harmful components before emitting to the atmosphere. Thus, the known exhaust pipe/discharge pipe has to accommodate the treatment device securely.

[00025] Generally, the gas treatment device is disposed within the discharge system. The treatment device has a light-off or operating temperature that has to be attained in shortest possible time for the treatment device to be optimally functional at best efficiency. To achieve early light-off, the treatment device may be disposed in proximity to the exhaust port. However, disposing the treatment device in proximity to the exhaust port may damage the treatment device itself thereby leading to poor durability which is primarily owing to exposure to the extremely high temperature of the discharge gases closer to the exit portion. If the treatment device is disposed away from the exhaust port, the treatment device would not achieve early light-off by which the exhaust gases would go untreated. Fig. 8 shows a graphical representation of conversion efficiency of a treatment device versus time in conventional systems. Line-A (dotted line) depicts the conversion efficiency of the treatment device from the time of engine start and till it reaches a maximum point or optimal point. As depicted, the conventional treatment device takes more time to reach its maximum efficiency for treatment of exhaust gas. In other words, the treatment device takes more time to reach its light-off temperature. Within this time large amount of exhaust gases go untreated which is undesirable. Thus, the challenge is to provide a discharge system with early light-off without damaging it.

[00026] Conventionally, a heating coil may be provided for heating the treatment device as the untreated gases are emitted during the first few minutes of starting the engine operation, which is before the treatment device becomes sufficiently operational. Some solutions in the art suggest provision of additional components like heating coil that help in bringing the treatment device to operating temperature quickly immediately after engine start. However, such a system is not cost effective and at the same time the system is not efficient as it consumes battery power for heating. The provision of heating coil or such electrical/electronic heating system may act as a deterrence to function of other electronic systems of the vehicle due to high power requirements by heating coils, which cannot be delivered by the alternator during engine start as the engine operates in lower RPM. Thus, the engine gets loaded due to power requirements or the battery is used. Additionally, packaging the additional heating system within layout with good ground clearance is difficult.

[00027] Furthermore, the exhaust gases that exit the exhaust port are travelling at high velocity and these gases funnel down towards the treatment device to only certain region leaving the other region of the treatment device underutilized. Presence of curved portion of the exhaust pipe immediately after the upstream end, which is majorly available in most layouts of the IC engines, causes the high velocity exhaust gases to flow along one side, say side opposite to the exhaust port, of the exhaust pipe and the exhaust gases reach the treatment device utilizing only a partial portion of the treatment device resulting in poor utilization of the treatment device. Additionally, only partial portion of the treatment device gets over utilized leading to early failure of the treatment device, which is undesired. As treatment device failure may require replacement of entire exhaust system which is a costly affair. For example, referring to Fig. 13, line LI depicts the uniformity index at various flow rates of the engine in a conventional system. The line LI shows that there is poor utilization of the treatment device due to poor surface uniformity/ face uniformity of flow of exhaust gasses. This also may provide fluctuating information of the oxygen content due to poor uniformity.

[00028] For example, in a forwardly inclined engine, the exhaust gases exiting the downward facing side of the exhaust port get funnel down flowing towards the treatment device. Nevertheless, the exhaust gases get attached to certain portion of the exhaust pipe causing only some portion of the treatment to be utilized. This occurs due to the high velocity exhaust gas passing through only certain region of the exhaust passage, whereas other portions of the exhaust gas travel with poor velocity and also results in turbulence affecting flow. Additionally, the exhaust gases flowing at high velocity will be passing quickly through the treatment device leaving minimal time for the conversion/treatment to take place. This results in poor conversion treatment of the discharge gases.

[00029] Further, an additional challenge is to accommodate a treatment device in a discharge system in vehicles having a forwardly inclined engine. In such vehicles, ground clearance of the vehicle with reference to the position of the exhaust port is substantially low for accommodating and routing the discharge pipe at such compact ground clearance. In the art, some solutions were proposed to address the problem of accommodation of treatment device, for example the treatment device is disposed at a split portion of the discharge pipe by using two holders on either sides of the treatment device. Such systems involve multiple welding points, which are considered weak points in terms of leaks or even in terms structural strength, as the discharge system is rigidly connected the IC engine. In the aforementioned systems, the exhaust pipe is to be split, two device-holding members are to be provided on either sides of the treatment device, and the treatment device is disposed in a casing resulting in increase in number of components, which implies increase in number of joints which is challenging. The discharge pipe provided with the treatment device gets suspended and such aforementioned multiple parts increases weight of the system that makes the joints vulnerable for failure owing to own weight of the system, resonance forces, fatigue loads and due to external parameters like jerks or vibrations.

[00030] At this outset, additional challenge is to accommodate such aforementioned discharge systems in compact saddle-ride type vehicle by maintaining sufficient ground clearance and to optimally dispose the discharge system. In order to maintain ground clearance, the discharge pipe requires sharp bending, which is complicated in tubular parts. Also, the treatment device cannot be accommodated close to the bend in such systems. Thus, the light-off of the treatment device is poor offering performance of the powertrain as a whole.

[00031] Moreover, the IC engine is provided with a lambda sensor or oxygen sensor, which is used to measure and monitor the amount of residual oxygen in the exhaust gas. The data provided by the lambda sensor is used by a control unit to alter/regulate the air-fuel mixture being supplied to the IC engine. Thus, the lambda sensor is required to be mounted on the exhaust system.

[00032] Similar to the conversion device, the lambda sensor also needs to disposed at optimum distance from the exhaust port. Generally, the lambda sensor being disposed on the exhaust pipe is known in the art, wherein the lambda sensor is disposed at a point where the information provided by the sensor is not absolute. However, such a design requires separate provision for sensor on the exhaust pipe, which increases the size of the exhaust pipe. Moreover, for optimum functioning of the exhaust pipe, it is to be disposed in proximity to the exhaust port, specifically it is to be disposed in the proximity to a curved portion of the exhaust pipe, which is a major challenge due to the complexity in mounting the sensor on a curved surface. Additionally, provision of the lambda sensor on the exhaust pipe may lead to leakage of exhaust gases whereby the lambda sensor would not be able to provide accurate exhaust gas related data, say the oxygen content. Thus, the control unit tends to alter/regulate the air-fuel mixture depending on the inaccurate data. This affects the performance of the engine resulting in rich mixture or lean mixture at undesired engine operating conditions. Moreover, an additional plate/ casing may be provided to provide a tight seal from escape of exhaust gases that increases size of the exhaust system especially that of the exhaust pipe, which is generally tubular member, affecting the layout of the vehicle. For example, in a vehicle having a forwardly inclined engine, the ground clearance of the vehicle is affected.

[00033] Besides, the lambda sensor should be able to provide the oxygen content related data prior to treatment and in some cases an additional lambda sensor may be used to get the data post conversion. Thus, there is design conundrum to accommodate the treatment device and the lambda sensor optimally in proximity to the exhaust port.

[00034] Thus, there is a need for addressing the aforementioned and other shorts comings in the prior art. Consequently, the discharge system should be capable of offering reduced weak points like joints offering structural rigidity to the system. Also, the discharge system should be capable of providing optimum performance. [00035] Hence, the present subject matter provides a discharge system for a motor vehicle. The motor vehicle comprises a power unit including an internal combustion (IC) engine. A cylinder head of the IC engine includes an exhaust port provided on one of side walls thereof. The discharge system includes a discharge pipe having one end connected to the exhaust port and other end connected to a muffler. In one embodiment, a primary treatment device is provided within the muffler and a preliminary treatment device is provided in the discharge pipe in proximity to the exhaust port.

[00036] It is a feature of the present subject matter that the discharge pipe includes a first portion a second portion, wherein the second portion is disposed downstream to the first portion with respect to exhaust gas flow direction. The discharge pipe is connected to the exhaust port through the first portion and the second portion gets connected to the muffler. Thus, the discharge pipe of the present subject matter is a compact unit with primarily two parts viz. a first portion and a second portion, which are minimal compared to similar conventional systems.

[00037] It is a feature of the present subject matter that a preliminary treatment device is at least partially enclosed/accommodated in the first portion, which is in proximity to the exhaust port offering early light-off thereof. It is an aspect that the first portion defines an accommodation space capable of accommodating the preliminary treatment device in proximity to the exhaust port and still offers sufficient ground clearance.

[00038] It is another feature of the present subject matter that the second portion supports the preliminary treatment device and the first portion enclosing the preliminary treatment device is connected to the second portion. The preliminary treatment device is not intermediately disposed, which would typically require multiple welding or connections. Thus, the number of weak points are reduced as the number of joints (welds) are reduced.

[00039] It is yet another aspect of the present subject matter that the preliminary treatment device is cantilevered/cantilever mounted to one of a first portion and a second portion. In one embodiment, an upstream end portion of the second portion is adapted to cantilever support the treatment device. The term‘cantilever mounted’ used herein infers that one end (downstream end) of the preliminary treatment device is upstream end portion of the second portion, and other end portion of the preliminary treatment device is suspending within the first portion without any direct contact therewith.

[00040] In one embodiment, the second portion is formed by one or more tubular metallic pipe(s). In one another embodiment, the second portion may include concentrically disposed tubular metallic pipe(s). Further, the first portion is formed by one or more sub-members. The one or more sub-members are connected to each other forming a space capable of accommodating at least a portion of the preliminary treatment device.

[00041] In one implementation, the first portion is formed by a first sub-member and a second sub-member that are partitioned along at least a plane passing along the axis. The first sub-member and the second sub-member are connected to each other forming an annularly closed structure. Additionally, the first portion includes a flange member secured to an upstream end portion of the sub-members. The first portion gets secured to the exhaust port through the flange portion.

[00042] It is an aspect that in one embodiment, the second portion includes a clutching member that is secured to the upstream end portion of the second portion, wherein the clutching member is adapted to support the preliminary treatment device as the clutching member can have a different cross-sectional profile that can match with both the second portion and the treatment device. In other embodiment, the clutching member may be integrally formed with the second portion by forming the clutching member.

[00043] In one implementation, the preliminary treatment device is cantilevered/ cantilever mounted to the clutching member and may be additionally supported by one or more support blocks provided on an inner periphery of the first portion to annularly support the treatment device.

[00044] In one implementation, the sub-members are having substantially C- shaped profile. The C-shaped profile or curved outward profile used herein may be formed by any symmetric/asymmetric geometrical profile having an opening towards one side. The two or more C-shaped sub-members that get connected together form a volume therein to accommodate the treatment device thereby acting as the cover for the treatment device.

[00045] It is a feature of the present subject matter that the discharge pipe has one or more bends whereby the direction of extension of the discharge pipe is altered and the first portion includes at least one bend and the second portion includes at least one bend. Further, the at least one bend of the first portion is formed by bending of the sub-member(s).

[00046] It is a feature of the present subject matter that the exhaust gas exiting the power unit enters first portion of the discharge pipe. Additionally, at least a portion of the exhaust gas passes into a gap, which is formed substantially radially between the first portion and the treatment device. The exhaust gas entering the gap helps in quick heating of the preliminary treatment device by which it attains early light-off. As the gap formed annularly outward of the treatment device enables the exhaust gas to heat the treatment device from annularly outward direction.

[00047] It is an additional feature of the present subject matter that the treatment device, in one embodiment, is disposed between a first bend and a second bend. Further, discharge pipe undergoes the first bend with an upper circumferential portion/surface thereof subsequent to the first bend being disposed at a first distance from an imaginary horizontal line passing through an upstream peripheral end. The first distance is attained by the sub-members that are having shorter radius of curvature at the first bend. Unlike in a tubular member that gets complicated to provide sharper bends.

[00048] It is yet an additional feature that the first portion has a lower circumferential portion/surface, taken subsequent to the first bend, disposed at a second distance from the imaginary horizontal line whereby the second distance is kept closer to the exhaust port whereby the discharge system in spite of being on lower facing side of the IC engine offers optimal ground clearance.

[00049] In one embodiment, the discharge system is secured to the power unit being forwardly-inclined type and the power unit is swingably mounted to a frame member through a toggle link. [00050] It one embodiment, the primary treatment device is having a volume greater than a volume of the preliminary treatment device. Thus, the primary treatment device is comfortably accommodated in the muffler and the preliminary treatment device is accommodated in the discharge pipe.

[00051] However, the scope of the present subject matter is not limited to a discharge system having a preliminary treatment device disposed in the discharge pipe and the primary treatment device disposed in the muffler. As it is applicable to a discharge system having one of the primary treatment device or the preliminary treatment device being disposed in the discharge pipe and the other of the primary treatment device or the preliminary treatment device being disposed in the first portion, as the first portion is capable of accommodating any of the treatment device.

[00052] In one embodiment, the discharge pipe is having a first portion formed by one or more sub-member(s), which is capable of accommodating a treatment device. The treatment device includes a sleeve that supports a substrate, wherein the sleeve is provided with an upstream extended portion formed upstream of the substrate. The substrate of the treatment device, typically, supports catalytic material and the substrate is also referred to as‘catalyst support’. The substrate is capable of offering large surface area. For example, the substrate may have a honeycomb structure. The upstream extended portion forms a hollow region upstream of the substrate and a first resistance member is provided thereat. The first resistance member slows down the exhaust gas that reaches the first resistance member and causes the exhaust gases to flow there through. In one implementation, the first resistance member includes plurality of perforations through which the exhaust gases flow causing uniform flow of gases with improved uniformity index at all flow rates. The uniformity index/flow uniformity index provides distribution of a quantity, which is exhaust gas herein, about a surface. Thus, the entire treatment device utilization is achieved due to substantially uniform flow of gases instead of from one region. Moreover, such improvement in flow uniformity index, improves the heat distribution in the discharge pipe. [00053] In one embodiment, the treatment device is provided with a downstream extended portion provided downstream of the substrate. A second resistance member is provided at the downstream end portion of treatment device to further reduce the velocity of exhaust gases to improve the treatment of exhaust gases by improving time spent in the treatment device.

[00054] In a preferred embodiment, the second resistance member is provided with perforations is integrally formed with the sleeve. This also, enables early light- off treatment especially during cold start conditions. Further, the second resistance member is selectively provided depending on back-pressure of the IC engine.

[00055] In one embodiment, treatment device is configured to support a sensor member mounted on a sleeve thereof. In one implementation, the sensor member is mounted to the upstream-extended portion of the sleeve through a mounting bracket for providing oxygen content information for regulating engine related parameters like air- fuel mixture etc.

[00056] The sensor member is securely and rigidly supported by the sleeve without compromising the structural rigidity of the discharge pipe. Further, in one implementation, the first portion that at least partially encloses the treatment device is provided with an aperture to enable a mounting bracket to be secured to the sleeve there through. The sensor member is provided subsequent to the first resistance member and the uniform flow of exhaust gas improves the sensitivity or detection of oxygen information.

[00057] The first resistance member disposed upstream of the substrate and the sensor member protects them any impulsive heat spikes thereby improving reliability of the system. Further, the improved uniformity index of flow of exhaust offers improved surface uniformity by which utilization of entire region of the treatment device is achieved thereby reducing early depletion of certain region of the substrate. As early depletion of even a certain region of the substrate requires replacement of treatment device or is some cases replacement of entire discharge system, which is addressed by the present subject matter.

[00058] In an embodiment, the treatment device is supported by the first portion, wherein an annular ring is provided to cantilever support the treatment device. Preferably, the annular ring is made of thermally non-conducting or a material with poor thermal conductivity, thereby eliminating any heat conduction from the treatment device to the first portion. Thus, the first portion acts as a casing for the treatment device and the same time is kept in isolation from the treatment device.

[00059] ???

[00060] These and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.

[00061] Arrows wherever provided in the top right corner 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.

[00062] Fig. 1 depicts an exemplary motor vehicle 100, in accordance with an embodiment of the present subject matter. The vehicle 100 has a frame member 105 that includes a head tube 106, a main frame 107 extending rearwardly downward from the head tube 106. The main frame 107 may comprise one or more main tube(s), and a pair of rear tubes 108 extending inclinedly rearward from a rear portion of the main tube. In the present embodiment, the vehicle 100 includes a step-through portion 109 defined by the frame member 105 of the vehicle 100. However, the aspects of the present subject matter are not limited to the depicted layout of the vehicle 100.

[00063] Further, a handlebar assembly 110 is connected to a front wheel 115 through one or more front suspension(s) 120. A steering shaft (not shown) connects the handlebar assembly 110 to the front suspension(s) 120 and the steering shaft is rotatably journaled about the head tube 106. A power unit 125 including an internal combustion (IC) is mounted to the frame member 105. The power unit 125 may also include a traction motor either hub mounted or mounted adjacent to the IC engine. In the depicted embodiment, the power unit 125 is disposed below at least a portion of the rear frame(s) 108. However, the power unit may be fixedly disposed to and below the main tube 107. In one implementation, the power unit 125 includes the IC engine, which is forwardly inclined type i.e. a piston axis (not shown) of the IC engine is forwardly inclined. The power unit 125 is functionally connected to a rear wheel 130 through a transmission system (not shown). The vehicle may include one or more rear wheel(s). The transmission system includes any one of a continuously variable transmission (CVT), a fixed gear ratio transmission, or automatic-manual transmission (AMT) controlled by an AMT control unit. Further, the vehicle 100 includes an air induction system (not shown) that provides air to an air-fuel mixing unit (not shown). A fuel tank (not shown) stores and supplies fuel to the air-fuel mixing unit, wherein the air-fuel mixing unit can be a carburetor or a throttle body with fuel injector. Also, the vehicle 100 includes a discharge system 200 that helps in dissipation of exhaust gasses from the IC engine. The discharge system 200 includes a muffler 135 mounted to the vehicle 100. In the depicted embodiment, the muffler 135 is disposed towards one lateral side of the vehicle 100.

[00064] Further, the rear wheel 130 is connected to the frame member 105 through one or more rear suspension(s) (not shown). In the depicted embodiment, the power unit 125 is swingably mounted to the frame member 105 through a toggle link 150 or the like. A seat assembly 140 is supported by the frame member 105 and is disposed rearward to the step-through portion 109.

[00065] Further, the vehicle 100 includes a front fender 155 covering at least a portion of the front wheel 115. In the present embodiment, a floorboard 145 is disposed at a step-through portion 109 and is supported by the main frame 107 and a pair of floor frames (not shown). The user can operate the vehicle 100 by resting feet on the floorboard 145, in a sitting position. In an embodiment, a fuel tank (not shown) is disposed below the seat assembly 140 and behind the utility box. A rear fender 160 is covering at least a portion of the rear wheel 135. The vehicle 100 comprises of plurality of electrical/electronic components including a headlight 165, a tail light (not shown), a battery (not shown), a transistor controlled ignition (TCI) unit (not shown), an alternator (not shown), a starter motor (not shown). Further, the vehicle 100 may include a synchronous braking system, an anti-lock braking system. [00066] The vehicle 100 comprises plurality of panels that include a front panel 170 disposed in an anterior portion of the head tube 106, a leg-shield 171 disposed in a posterior portion of the head tube 106. A rear panel assembly 172 includes a right side panel and a left side panel disposed below the seat assembly 140 and extending rearward from a rear portion of the floorboard 145 towards a rear portion of the vehicle 100. The rear panel assembly 172 encloses a utility box disposed below the seat assembly 140. Also, the rear panel assembly 172 partially encloses the power unit 125. Also, the muffler 135 of the discharge system is coupled to exhaust side of the IC engine and in an implementation the muffler 135 is disposed towards one lateral side of the vehicle 100.

[00067] Fig. 2 illustrates a front perspective view of the power unit, in accordance with an embodiment of the present subject matter. The power unit 125 of the present subject matter is the IC engine that is a forwardly inclined type. Further, the IC engine is swinging type that is swingably connected to the frame member 105 the vehicle 100 through a crankcase 181. The crankcase 181 is connected to the frame member 105 using a toggle link 150. One end of the toggle link 150 is connected to lower portion of the crankcase 181 and other end of toggle link 150 is pivoted to the frame member 105.

[00068] Further, the IC engine includes a cylinder portion defined by a cylinder block 180. The cylinder block 180 is mounted to a crankcase 181 of the IC engine. The cylinder block 180 supports a cylinder head 183 that includes a valve assembly. The valve assembly enables entry of air-fuel mixture into the cylinder portion, where the combustion of air-fuel mixture takes place. Subsequently, the valve assembly enables dissipation of the burnt exhaust gases EG (as shown in Fig. 7 (c)) from the cylinder. The air induction system along with air fuel supply system is connected to one side wall of the cylinder head 183 that is provided with an input port (not shown). Further, the cylinder head 183 includes an exhaust port 184 provided on other side wall of the cylinder head 183. In the present implementation, the input port is provided on the upper side wall of the cylinder head 183 and an air fuel regulating unit, which may include a carburetor or a throttle body with fuel injector connected to the input port. Further, in the present implementation, the exhaust port 184 is provided on bottom side wall of the cylinder head 183 and the discharge system 200 is connected to the exhaust port 184. The IC engine includes a cooling cowl assembly 185 (partially shown) that annularly encloses at least a portion of the cylinder head 183, and the cylinder block 180. The discharge system 200 includes a discharge pipe 205 that functionally connects the cylinder head 183 to the muffler 135. In the present implementation, the muffler 135 is disposed laterally adjacent to the rear wheel 130.

[00069] Fig. 3 depicts a right side perspective view of the discharge system 200, in accordance with the embodiment of Fig. 2. The discharge system 200 includes the discharge pipe 205 formed by a first portion 206 and a second portion 207, wherein the second portion 207 is disposed downstream to the first portion 206 with respect to direction of flow of the exhaust gas. The discharge system 200 is connected to the exhaust port 184 (shown in Fig. 2) through an upstream end portion of the discharge pipe 205, hereinafter the upstream end portion of the exhaust pipe 205 is referred to as a first-upstream end portion 208 thereof. Further, the discharge pipe 205 includes a downstream end portion through which it is connected to the muffler 135, hereinafter the downstream end portion of the exhaust pipe 205 is referred to as a second-downstream end portion 216. The discharge system 200 includes a primary treatment device 210 disposed downstream to the preliminary treatment device 211 and the primary treatment device 210 which is disposed in at least one of the second portion 207 and a muffler 135. In the depicted embodiment, the primary treatment device 210 is disposed within the muffler 135, for treating the exhaust gases EG passing there through. The muffler 135 includes one or more mounting brackets 190, 191 for mounting the muffler 135 to the frame member 105. Furthermore, a preliminary treatment device 211 is disposed within the first portion 211 of the discharge pipe 205. Thus, the exhaust gases EG exiting the cylinder head 183 (shown in Fig. 2) is treated by the preliminary treatment device 211 and the primary treatment device 210 thereby enabling dissipation of exhaust gases EG from the muffler 135 with minimal pollutants.

[00070] In the depicted embodiment, the second portion 207 is a single tubular metallic pipe that is having one end secured to the first portion 206 and other end secured to an inlet portion of the muffler 135. The second portion 207 is capable of supporting at least a portion of the preliminary treatment device 211 and the preliminary treatment device 211 is substantially enclosed by the first portion 206. Thus, the preliminary treatment device 211 is in minimal contact or with no-contact with the first potion 206 in spite of the enclosing it. The second portion 207 is secured to first portion 206 by welding or through any other known securing mechanism. The second portion 207 is having a length longer than the length of the first portion 206, wherein the term‘length’ used here is referring to true length in axial direction along the central contour axis of the exhaust system.

[00071] In one implementation, an overall conversion efficiency or output of the preliminary treatment device 211 is lesser compared to an overall conversion efficiency or output of the primary treatment device 210. Accordingly, the primary treatment device 210 is having a volume greater than a volume of the preliminary treatment device 211. The primary treatment device 210 can be comfortably accommodated in the muffler 135 and the preliminary treatment device 211 is accommodated in the discharge pipe 205. However, the first portion 206 of the present subject matter can be adapted to accommodate the high volume primary treatment device 210 therein. Each of the treatment device mentioned herein can be in form a single integrated member or a segregated member either connected to each other or disposed with some spacing. Furthermore, the discharge system 200 is suspended on the vehicle through the first end portion 208 and the mounting brackets 190, 191.

[00072] Fig. 4 depicts an exploded view of a portion of the discharge system, in accordance with the embodiment as depicted in Fig. 3. The second portion 207, which is a tubular metallic pipe having circular section, in the present embodiment, having a second-upstream end portion 215 connected to the first portion 206 through a clutching member 217 and other end, which is the second-downstream end portion 216 is connected to the muffler 135.

[00073] The first portion 206 is formed by one or more sub-members 221, 222. In the present embodiment, the first portion 206 is formed by two sub-members viz. a first sub-member 221 and a second sub-member 222 that are partitioned in a plane along the contoured axis of the discharge pipe 205. Additionally, the first portion 206 includes a flange member 223 that is secured to the sub-members 221, 222 at an upstream portion. The flange member 223 holds the sub-members 221, 222 together at one end and is also acting as mounting member for mounting the discharge pipe 205 to the IC engine. The first portion 206 is capable of enclosing at least a portion of the preliminary treatment device 211 with minimal or no-contact therewith. In the present embodiment, the preliminary treatment device 211 is completely enclosed, especially annularly surrounded, by the first portion 206. The first portion 206 acts as a casing for preliminary conversion device 211 without actually supporting the device 211. Moreover, the sub-members 221, 222 enable in maintaining varying cross-sectional radius with sharp curvature subsequent to the upstream portion 208. Furthermore, the first portion 206 gets connected to the second portion 207 by a downstream end portion of the first sub-member 221 and the second sub-member 222, which are resting on the second-upstream end portion 215 of the second portion 207 annularly adhered and abutting thereto.

[00074] In one embodiment, the second portion 207 includes the clutching member 217, wherein the clutching member 217 acts as interfacing element between the second portion 207 and the preliminary treatment device 211. Thus, the preliminary treatment device 211 is cantilevered to the second-upstream end portion 215, wherein one end 218 (shown in Fig. 6) of the treatment device is mounted to the second-upstream end portion 215. The first-downstream end portion 209 of the first portion 206 is resting on/secured to the second-upstream end portion 215. Other end 219 of the preliminary treatment device 211 projects outwards or is suspended from the clutching member 217. Accordingly, the preliminary treatment device 211 is in no direct contact with the first portion 206 and is substantially supported by the second portion 207.

[00075] Fig. 5 depicts a portion of the discharge pipe with selected parts, in accordance with the embodiment of Fig. 4. The second portion 207 is provided with the clutching member 217, wherein the second-upstream end portion 215 is inserted at least partially into the clutching member 217 and is secured thereat. The means of securing will preferably be welding but may also include other known means of securing like interference-fit, snap-fit or the like depending on material or manufacturing requirements. Further, the preliminary treatment device 211 (shown in Fig. 4) is at least partially supported by the clutching member 217 from the other side. The clutching member 217 can be adapted to have non-uniform diameter say a first diameter at downstream side to receive the second-upstream end portion 207 thereat and a second diameter at upstream side for cantilever mounting of the preliminary treatment device 211. The clutching member 217 is having a tapered profile in the downstream direction, in accordance with the depicted embodiment. Further, the preliminary treatment device 211 that is cantilever mounted is substantially annularly enclosed by the first portion 206 and the clutching member 217 is at least partially annually enclosed by the first portion 206 thereby rigidly supporting the preliminary treatment device 211 and also providing a tight seal for the exhaust gases EG.

[00076] Fig. 6 depicts another portion of the discharge pipe with selected parts, in accordance with the embodiment of Fig. 4. The first portion 206 formed by the first sub-member 221 and the second sub-member 222, in accordance with the depicted embodiment, are separated in a vertical plane along an axis A- A’ thereof. In the current embodiment, the first sub-member 221 and the second sub-member

222 are symmetrical. However, asymmetrical sub-members may be used owing to design/ manufacturing/ welding or any other feasibility. The first sub-member 221 and the second sub-member 222 can be of a sheet metal part, a casted part, or a FRP part that are secured together by welding or the like. Further, the flange member

223 (shown in Fig. 4) gets welded to the first-upstream end portion 208 of the first portion 206, wherein the upstream end portion forms a substantially circular cross- section and the flange member 223 is capable of holding the two sub-members 221, 222 together by receiving at least a portion thereof. Further, the downstream end portion of the sub-members 221, 222 envelopes the clutching member 217 and are secured thereto.

[00077] Further, the first portion 206 has a bent profile having one or more bends whereby the direction of extension of the discharge pipe 205 is altered. In case of the IC engine being provided with exhaust port 184 on a downward facing side of the cylinder head 183, the bent profile enables extension of the discharge pipe 205 sideward and rearward towards the muffler 135. Whereas, in case of the IC engine having a substantially vertically or inclined piston axis, the first portion is provided with at least a bend adapted to extend in a downward and a sideward direction.

[00078] Fig. 7 (a), Fig. 7 (b), and Fig. 7 (c) show cut-sectional views of the discharge pipe 205 taken along axes B-B’, C-C’, and D-D’, respectively, of the discharge pipe 205 are shown in Fig. 7 (a). The axis B-B’ is taken substantially along a short axis mid-portion of the first portion 206. The sectional view taken along axis B-B’ depicts a gap 230 (also marked in the sectional view at D-D’) between the first portion 206 and the preliminary treatment device 211. In one embodiment, the gap 230 is kept in the range of 5-15% of a radius of the discharge pipe 205 (taken near the port 184) offering sufficient clearance for passage of exhaust gases EG and at the same time maintaining optimum size of the discharge pipe 205 to be mounted to a forwardly inclined engines. Moreover, the first portion 206 acts a cover for the preliminary treatment device 211, wherein the first portion 206 is disposed annularly around the preliminary treatment device 211 without coming in contact or with minimal contact therewith forming the gap 230. The exhaust gases EG leaving the exhaust port 184 flow through the preliminary conversion device 211. Also, the gap 230 enables exhaust gases EG to flow around the preliminary treatment device 211. The gap 230 is annularly formed around the preliminary treatment device whereby the exhaust gases EG that are hot surround the preliminary treatment device 211 thereby heating the preliminary treatment device 211 from outside leading to early light-off. Moreover, the gap 230 has only one entry-exit point, which is at upstream portion thereof, thereby causing the exhaust gasses EG entering the gap 230 to stay for longer duration causing quick heating even during cold start.

[00079] Furthermore, sectional view taken at axis C-C’, which is taken substantially at the downstream end portion of the first portion 206 depicts the second portion 207 being encircled by the clutching member 217, which is further encircled by the first portion 206. Thus, the clutching member 217 is securely sandwich mounted between the second portion 207 and the first portion 206 and the clutching member 217 can rigidly support the preliminary treatment device 211.

[00080] Further, a sectional view taken along axis D-D’ depicts the sectional view of the discharge pipe 205 taken along axis thereof. The first portion 206 includes the flange member 223 that is secured to an upstream end portion thereof, wherein the flange portion 223 is provided with one or more mounting apertures (not shown) for connecting to the cylinder head 183. Further, the flange member 223 includes a cylindrical upstream end that engages with an exhaust port 184 of the power unit 125. The cylindrical upstream end, in accordance with an embodiment, is protruded type that is adapted to be received by the exhaust port. In another embodiment, the cylindrical upstream end is hollow cylindrical type that can receive a protruded type exhaust port.

[00081] The first sub-member 221 and the second sub-member 222 are C-shaped (also shown in Fig. 4) that are connected to each other through the peripheral edges, whereby the two C-shaped Cl, C2 sub-members in assembled condition define a volume there between to accommodate the preliminary treatment device 211, at least a portion of the clutching member 217, and the second-upstream end portion 215 of the second portion 207. The plane PI, which is at joining of the peripheral edges can be passing through the axis thereof or disposed at an off-set from the axis. The cross-section of the sub-member is not limited to C-section and may include any known regular or irregular geometrical sections to accommodate the treatment device. The first portion 206 undergoes a first bend 240 subsequent to which the discharge pipe 205 undergoes a change in orientation and the preliminary treatment device 211 can be accommodated immediately after the first bend.

[00082] As depicted in the sectional view taken along axis D-D’, the first sub member 221 and the second sub-member 222 are provided with curved profile to form the first bend 240. In the present embodiment, each of the first sub-member 221 and the second sub-member 222 are having a first radius of curvature 231 and a second radius of curvature 232 respectively, taken at the angular portion of the first bend 240, wherein the first radius of curvature 231 being inward is smaller than the second radius of curvature 232. A ratio of the second radius of curvature 232 to the first radius of curvature 231 is in the range of 3 to 8 offering sharp angular profile without compromise of structural rigidity.

[00083] Further, moving in a downstream direction of flow of the exhaust gases EG through the first portion 206, the radius of the first portion 206 increases till the first bend 240 and is then gets stabilized at the center portion thereof. The stabilized radius will be substantially equal to a sum of a radius of the preliminary treatment device 211 and the gap 230. The second radius of curvature 232 can be modified whereby the resultant stabilized radius of the second portion 206 is capable of accommodating the preliminary treatment device 211 and still maintaining the gap 230. The gap 230 enables in heating of the preliminary treatment device 211 by allowing the exhaust gases EG to flow around. Furthermore, the first-downstream end portion 209 of the first portion 206 is abutting the clutching member 217 that is supporting the preliminary treatment device 211 being cantilever mounted to the clutching member 217. In other words, one end 218 of the preliminary treatment device 211 is supported by the clutching member 217, which in turn supported by the second portion 207. In one other implementation, the clutching member 217 may be integrally formed with the second portion 207, wherein the second- upstream end portion 215 is machined to provide the function of the clutching member 217.

[00084] Therefore, the exhaust gases EG exiting the power unit 125 enters the discharge pipe 205 through the first portion 206. The exhaust gases EG passes through the preliminary treatment device 211 where it undergoes treatment like oxidation of gases. Additionally, at least a portion of the exhaust gases EG passes into the gap 230, which is formed substantially around the preliminary treatment device 211, due to which it heats the preliminary treatment device 211 quickly. Thus, the exhaust gases EG passing through the preliminary treatment device 211 and that enters the gap 230 holistically results in quick heating of the preliminary treatment device 211 without the need for any additional components like heating elements, which make the system bulkier, requiring high currents, & adding to the cost of the system. Thus, the preliminary treatment device 211 attains early light- off thereby effectively treating the exhaust gases EG. [00085] Fig. 8 shows the conversion efficiency of the treatment device versus time. The line B depicts the conversion efficiency of the treatment device in accordance with the discharge system of the present subject matter. The conversion efficiency of the treatment device 211 reaches its maximum efficiency quickly after the start of the IC engine. The treatment device 211 reaches its maximum efficiency at a time t2, which is earlier than a time tl required for reaching the maximum efficiency in case of an exemplary conventional system. Thus, the present subject matter offers quick heating within a time t2 offering an advantage of Dΐ. Further, the slope of the line B is steeper compared to the line A (conventional system) which implies that the conversion efficiency is dramatically increasing immediately after the IC engine start and also attains early maximum conversion efficiency. Additionally, no direct connection between the preliminary treatment device 211 and the first portion 206, which is acting as the covering means/cover thereof, helps in minimizing loss of heat of the preliminary treatment device 211 as well as any damage from high temperatures & heat conduction related durability issues. Consequently, the preliminary treatment device 211 attains thermal equilibrium faster offering optimum performance thereof.

[00086] In the depicted embodiment, the first portion 206, subsequent to the first bend 240, is having an upper circumferential portion 226 disposed at a first distance 235 from an imaginary horizontal line 236 passing through an upstream peripheral end. The first distance 235 is lower such that the first portion 206 offers sharp bend offering orientation change and at the same time retaining the ability to accommodate the treatment device 211. The first distance 235 can be maintained in the range of 5 to 125 millimeters. Further, the discharge pipe 205 has a lower circumferential portion 227, taken subsequent to the first bend 240, at a second distance 237 from the imaginary horizontal line 236. The second distance 237 is maintained in the range of 50-175 millimeters offering optimum ground clearance between the discharge pipe 205 and the ground in spite of accommodation of the treatment device 211 therein.

[00087] The discharge pipe 205 undergoes the first bend 240, wherein the first portion 206 of the discharge pipe 205 extends substantially in laterally direction. Thus, the discharge pipe 205 does not extends into the toggle link 150 portion. Subsequently, the discharge pipe 207 undergoes a second bend (not shown) whereby the discharge pipe 205 extends towards the muffler 135. Further, the first portion 206 enables the preliminary treatment device 211 to be accommodated therein in proximity to the exhaust port 184 immediately after the first bend 240 keeping it close to the exhaust port 184 for early light-off. At the same time extension of the discharge pipe 205 in lateral direction and towards the ground is optimized.

[00088] In one embodiment, the power unit 125 comprising the IC engine is forwardly inclined type having a piston axis, also analogous to a cylinder axis, which is forwardly inclined. Further, the cylinder block 180 (shown in Fig. 2) is supported by the crankcase 181 which is constituted by two or more parts. Further, the cylinder head 183 mounted to the cylinder block 180 (shown in Fig. 2) includes the exhaust port 184 to which the discharge system 200 is connected. In the present embodiment, the flange member 223 (as shown in Fig. 4) gets secured to the exhaust port 184. The discharge pipe 205 extends towards a muffler 135 disposed either to leftward, or to rightward with respect to a lateral center of the motor vehicle 100. In one embodiment, the muffler 135 may be disposed at least partially along the lateral center. The discharge pipe 205 includes a first portion 206 and a second portion 207, and the second portion 207 substantially supports the preliminary treatment device 211, which is enclosed by the first portion 206. The preliminary treatment device 211 is cantilever mounted to the second portion 206. The first portion 206 enables quick heating of the treatment device 211 due to the gap 230. Also, the first portion acts as casing for the treatment device 211.

[00089] Fig. 9 depicts a sectional view of a portion of the discharge system taken along axis X-X’, in accordance with a second embodiment of the present subject matter. The discharge system 300 includes a discharge pipe 305 formed by a first portion 306 and a second portion 307. The first portion 306 is formed by one or more sub-members 321, 322. In the present embodiment, the first portion 306 is formed by a first sub-member 321 and a second sub-member 322 that are partitioned in a plane along the axis of the discharge pipe 305. The first portion 306 is capable of enclosing at least a portion of a treatment device 311, wherein one of the first portion 306 and the second portion 307 support the treatment device 311 with minimal contact. In the depicted embodiment, the second portion 307 supports the treatment device 311. Further, the first portion 306 gets connected to the second portion 307 by a downstream end portion thereof. The second portion 307 includes a clutching member 317, wherein the clutching member 317 acts as interfacing element between the second portion 307 and the first portion 306. Further, in one embodiment, the treatment device 311 is supported by the clutching member 317 (not shown). An annular ring 360 is provided to provide cantilever support to the treatment device 311 with minimal or no-contact with the first portion 306. Preferably, the annular ring 360 is made of thermally non-conducting or a low conducting material, thereby eliminating any heat conduction from the treatment device 311 to the first portion 306.

[00090] The annular ring 360 further defines a gap 330 between treatment device 311 , to be precise between the sleeve 312 and the inner periphery of the first portion 306. Also, the annular ring 360 blocks flow of exhaust gases EG from the gap 330 towards downstream of the annular ring 360. Thus, the annular ring 360 is disposed at a portion where the substrate 313 ends. Thus, the gap 330 extends till the region the substrate 313 extends thereby causing heating of the entire substrate 313 without any external heating elements.

[00091] In the current embodiment, the clutching member 317 has a tapering dimeter in a downstream direction. An upstream end portion 315 of the second portion 307 is secured to an inner periphery of the clutching member 317 and an upstream end portion of the clutching member 317 is secured to downstream end portion of the second portion 307. Specifically, the upstream end portion of the clutching member 317 is secured to downstream end portion of the first portion 306.

[00092] Further, in one embodiment, the treatment device 311 includes a sleeve 312 that supports a substrate 313. In one embodiment, the substrate 313 is adapted to match the structural profile of the sleeve 312, which is preferably circular/cylindrical. The substrate 313 may have a honeycomb structure (internal) with precious metal(s) such as platinum, palladium, rhodium, or similar materials loading for reduction process. The sleeve 312 includes an upstream-extended portion 314 that is extending in an upstream direction thereof beyond a portion about which the substrate 313 is supported. The first portion 306 formed by the sub members 321, 322 enables accommodation of the elongated treatment device 311 and also providing the cantilever mounting.

[00093] Further, the discharge system 300 is provided with a first resistance member 365 mounted to the treatment device 311 at an end portion thereof at upstream-extended portion 314. The sub-members 321, 322 forming the first portion enables the accommodation of the treatment device 311 in proximity to the flange member 232/exhaust port 184 (shown in Fig. 2) due to the swift / sharp increase in diameter of the first portion immediately subsequent to the exhaust port 184 (shown in Fig. 2). The exhaust gases EG flowing at high velocity from the exhaust port to the discharge system 300 enter the first portion 306 and come in contact with the first resistance member 365.

[00094] Firstly, the first resistance member 365 slows down the velocity of the exhaust gases EG passing there through, wherein the attachment of exhaust gases EG to one portion of wall of the first portion 306 is disrupted. The first portion 306 with larger second radius of curvature 232 (as explained in Fig. 7 (c)) may cause flow attachment to the side opposite to the exhaust port 184. The present subject matter with the first portion 306 in conjunction with the treatment device 311 causes the exhaust gases EG passing through the perforations, provided on the first resistance member 365, by which uniform surface utilization of the treatment device 311 is improved. Moreover, this also leads to increase in time spent by exhaust gases EG passing through the substrate 313 due to reduced speed. Furthermore, this additionally leads to early light-off of the treatment device 311 due to retention of hot exhaust gases EG for more time. In one embodiment, the first resistance member 365 is having an area of perforated holes to be equivalent to 50-80% of a total frontal area / face area of the treatment device 311, which helps in optimal disruption of high velocity gases flowing along a certain region thereby causing uniform flow through the perforations. [00095] Fig. 10 (a) depicts another implementation of the present subject, in accordance with an embodiment. In the present embodiment, the treatment device 311 is configured to support a sensor member 345 at the upstream-extended portion 314. In the depicted embodiment, the sensor member 345 is mounted to the upstream-extended portion 314 through a mounting bracket 350. The first portion 306 is provided with an aperture 355 to enable a mounting bracket 350 to be secured to the upstream-extended portion 314 of the treatment device 311. The mounting bracket 350 can be a cylindrical bolt or a mounting boss, which is secured to the upstream-extended portion 314 and in an embodiment, it partially enters the inner hollow region of the treatment device 311. Further, a sensor member 345, like a lambda sensor, an oxygen sensor or the like, is secured thereat extending into the inner hollow region. The annular ring 360 is disposed at a portion where the substrate 313 ends. Thus, the gap 330 extends till the region the substrate 313 extends thereby causing heating of the entire substrate 313 without any external heating elements. Also, the sensor member 345 undergoes quick heating due to the exhaust gases EG passing through the gap 330.

[00096] Furthermore, the inward edges 356 of the aperture 355 are bent inward so as to abut an outer periphery of the sleeve 312 by which it acts as a seal restricting any escape of exhaust gases EG there through. This enables the sensor member 345 to be mounted immediately after a first-upstream end portion 308 of the exhaust pipe 305 with a pre-determined gap. This enables the sensor member 345 to be optimally mounted in proximity to the exhaust port 184 for providing the oxygen content information that leaves the exhaust port 184. Moreover, the turbulence around the sensor member 345 caused due to the first resistance member 365 improves the sensitivity or detection of oxygen information. Additionally, the first resistance member 365 (as shown in Fig. 9) protects the sensor member 345 and the treatment device 311 from any impulsive heat spikes that may occur during various operating conditions of the engine.

[00097] Further, an annular ring 360 is provided to provide cantilever support to the treatment device 311. Preferably, the annular ring 360 is made of thermally non conducting or a low conducting material, thereby eliminating any heat conduction from the treatment device 311 to the first portion 306. Thus, the treatment device 311 is either cantilever mounted to the second portion 307 of the exhaust pipe 305 or cantilever mounted to the annular ring 360 eliminating need for any additional mounting scheme the first portion 306 is formed by the first sub-member 321 and a second sub-member 322 that are partitioned in a plane along an axis of the discharge pipe 305. Thus, the first portion 306 is capable of enclosing at least a portion of the preliminary treatment device 311 and also supporting it through the annular ring 360 thereby offering an effective design with minimal connections, especially to support the treatment device 311.

[00098] Fig. 10 (b) depicts yet another implementation of the discharge system of the presents subject matter. The discharge system 301 is provided with a first resistance member 365 mounted to the treatment device 311 at an upstream end portion thereof. The exhaust gases EG flowing at high velocity from the exhaust port to the discharge system enters the first portion 306 and comes in contact with the first resistance member 365 that is adapted to slow down the velocity of the exhaust gases EG passing through there through. Further, the first resistance member 365 has passage portions like perforation through which the exhaust gases EG passes at uniform speed. This also helps in maintaining uniform temperature in the first portion 306.

[00099] Fig. 11 depicts a discharge system 400, in accordance with another embodiment of the present subject matter. Fig. 12 depicts an exploded view of the discharge system 400. The discharge system 400 according to the depicted embodiment includes a discharge pipe 405 formed by a first portion 406 and a second portion 407. The first portion 406 is formed by one or more sub-members 421, 422. Further, in one embodiment, the treatment device 411 includes a sleeve 412 that supports a substrate 413. The treatment device 411 is configured to support a sensor member 345 at the upstream-extended portion 414, which is formed at an upstream portion of the substrate 413. The treatment device 411 is supported by an annular ring 460, wherein the treatment device 411 is cantilever supported by the annular ring 460. However, in one embodiment, a clutching member 417 supports the treatment device 411 in a cantilever manner. The cantilever mounting of the treatment device 411 reduces the number of connection points and reduced contact portion whereby the first portion 406 offers thermal isolation. In one embodiment, the sensor member 345 is mounted to the treatment device 411 at the upstream- extended portion 414 through a mounting member 350. As shown in Fig. 12, one of the sub-members, which is the second-sub member 422 in this case is provided with an aperture 455 to mount the mounting member 350 there through.

[000100] Further, the discharge system 400 is provided with a first resistance member 465 mounted to the treatment device 411 at an end portion thereof. The exhaust gases EG flowing at high velocity from the exhaust port to the discharge system enters the first portion 406 and comes in contact with the first resistance member 465. In one embodiment, the first resistance member 465 is having an area of perforated holes to be equivalent to 50-80% of a total frontal area of the treatment device 411. Firstly, the first resistance member 465 slows down the velocity of the exhaust gases EG passing through there through. This leads to increase in time spent by exhaust gases EG passing through the substrate 413 due to reduced speed. Furthermore, this additionally leads to early light-off of the treatment device 411.

[000101] Further, in the depicted embodiment, the treatment device 411 includes a downstream-extended portion 475 formed downstream to the substrate 413. Further, the downstream-extended portion 475 is provided with a second resistance member 466. The second resistance member 466 can be a perforated plate, a perforated cylinder or the like. In the depicted embodiment, the second resistance member 466 is formed as a perforated cylindrical member. In other words, the second resistance member 466 may be internally formed with the downstream- extended portion 475 and a stopper plate 480 is provided on the downstream end of the treatment device 411.

[000102] As depicted in Fig. 13, a line L2 which depicts the uniformity index at various flow rates of the IC engine according to present subject matter. As shown, the present subject matter offers an improvement of D g of the uniformity index thereby providing improved detection of oxygen content information. As the discharge pipe 205, 305, 405 enables the accommodation of the treatment device 211, 311, 411 even with the extended portions due to the sub-members 221, 222, 321, 322, 421, 422 that provides a swift varying diameter and with sharp orthogonal bend to accommodate the treatment device 211, 311, 411 thereat. Also, the first portion 206, 306, 406 with the swift varying diameter that flares in downstream direction enables accommodation of the resistance member 365 comfortably at upstream portion of the substrate 213, 313, 413 thereby enabling the exhaust gases EG passing along certain portion of the discharge pipe 205, 305, 405 to spread about the area of the treatment device 211, 311, 411. Furthermore, the first resistance member enables the exhaust gases EG to pass there through at a uniform rate and the sensor member 345 disposed subsequent to the first resistance member 365 is capable of providing unfluctuating data of the oxygen content thereby enabling regulation of the air-fuel mixture. Thus, the first portion 206, 306, 406 in conjunction with the sensor member 345 mounted to the treatment device 211, 311, 411 improves the detection of the oxygen with minimal fluctuation.

[000103] Thus, the exhaust gases EG subsequent to passing through the substrate 413 reaches the perforations radially provided at the downstream-extended portion 475 by which a further reduction in speed of the exhaust gases EG is achieved thereby enabling effective utilization of treatment device. In one implementation, an overall area of all the perforated holes provided in all the resistance members is equivalent to 100-150% of the total frontal area of an axial face/frontal face of the treatment device 522. Thus, provision at such resistance members 465/466 enables exhaust gases EG to have substantial time at the substrate portion leading to effective treatment of the exhaust gases EG. Moreover, retention of exhaust gases EG about the substrate region enables the treatment device to attain early light-off. The resistance member(s) 465, 466 enables improved surface uniformity and uniformity of the exhaust gases EG entering the treatment device thereby. Thus, instead of specific region of the substrate 413 of the treatment device 411 being utilized, an overall area of the substrate is utilized.

[000104] 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 List of reference signs:

100 vehicle 313/413 substrate

105 frame member 314/414 upstream extended portion

106 head tube 215 second-upstream end portion 107 main frame 216 second-downstream end portion

108 rear frame 45 217/317/417 clutching member

109 step-through space 221/321/421 first sub-member

110 handlebar assembly 222/322/422 second sub-member

115 front wheel 223/323/423 flange member

120 front suspension 226 upper circumferential portion 125 power unit 50 227 lower circumferential portion

130 rear wheel 230/330 gap

135 muffler 231 first radius of curvature

140 seat assembly 232 second radius of curvature 145 floorboard 235 first distance

150 toggle link 55 236 horizontal line

155 front fender 237 second distance

160 rear fender 240 first bend

165 headlight 345 sensor member

170 front panel 350 mounting bracket

171 leg shield 60 355/455 aperture

172 rear panel assembly 356 inward edge

180 cylinder block 360/460 annular ring

181 crankcase 365/465 first resistance member 182 toggle link 466 second resistance member

183 cylinder head 65 475 downstream extended portion

184 exhaust port 480 stopper member

190 mounting member EG exhaust gas

200/300/301/400

discharge system

205/305/405 discharge pipe

206/306/406 first portion

207/307/407 second portion

208/308 first-upstream end

portion

209 first-downstream end portion

210 primary treatment device

211/311/411 preliminary treatment

device

312/412 sleeve

Claims

We claim:

1. A discharge system (200, 300, 301, 400) for a motor vehicle (100), said discharge system (200, 300, 301, 400) connected to a power unit (125) of said motor vehicle (100), the discharge system (200) comprising:

a discharge pipe (205, 305, 405), said discharge pipe (205, 305, 405) formed by a first portion (206, 306, 406) and a second portion (207, 307,

407), said first portion (206, 306, 406) connected to an exhaust port (184) of said power unit (125) through a first-upstream end portion (208, 308,

408) thereof, said second portion (207, 307, 407) disposed downstream of said first portion (206, 306, 406), one of said first portion (206, 306, 406) and said second portion (207, 307, 407) being adapted to support a treatment device (211, 311, 411), and

said first portion (206, 306, 406) capable of at least partially annularly enclosing said treatment device (211, 311, 411), and said first portion (206, 306, 406) includes a first-downstream end portion (209) secured to said second portion (207, 307, 407).

2. The discharge system (200, 300, 301, 400) as claimed in claim 1, wherein said first portion (206, 306, 406) provides at least partial annular gap (230, 330) formed between said treatment device (211, 311, 411) and an inner periphery of said first portion (206, 306, 406).

3. The discharge system (200) as claimed in claim 1, wherein said second portion (207) includes a second-upstream end portion (215), and said treatment device (211) is cantilevered to the second-upstream end portion (215), and wherein one end (218) of said treatment device (211) is supported by said second-upstream end portion (215) and other end (219) of said treatment device (211) projects outwards therefrom.

4. The discharge system (200) as claimed in claim 1, wherein said second- upstream end portion (215) includes a clutching member (217), said treatment device (211) being cantilevered to the clutching member (217), and said clutching member (217) integrated with second-downstream end portion (216).

5. The discharge system (200) as claimed in claim 1, wherein said treatment device (211) cantilevered to said second-upstream end portion (215) acts as a preliminary treatment device (211) having an overall conversion efficiency lesser than an overall conversion efficiency of a primary treatment device (210), and said primary treatment device (210) disposed downstream of said preliminary treatment device (211).

6. , The discharge system (200) as claimed in claim 5, wherein said primary treatment device (210) is disposed in at least one of said second portion (207) and a muffler (135).

7. The discharge system (200) as claimed in claim 1, wherein said treatment device (211) acts as a primary treatment device having an overall conversion efficiency greater than an overall conversion efficiency of a preliminary treatment device disposed downstream of said primary treatment device.

8. The discharge system (300, 301, 400) as claimed in claim 1, wherein said discharge system (300, 301, 400) includes an annular ring (360) adapted to cantilever support said treatment device (311, 411) about said first portion (306, 406), and said second portion (307, 407) includes a clutching member (317, 417) acting as interfacing element between said first portion (306, 406) and said second portion (307, 407).

9. The discharge system (200, 300, 301, 400) as claimed in claim 1, wherein said first portion (206, 306, 406) is formed by one or more sub-member(s), wherein said one or more sub-member(s) includes a first sub-member (221, 321, 421) and a second sub-member (222. 322, 422) partitioned at least along an axis (A-A’) of said first portion (206, 306, 406), and each of said first sub-member (221, 321, 421) and said second sub-member (222, 322, 422) are curved outward, and said first sub member (221, 321, 421) and said second sub-member (222, 322, 422), in assembled condition, define a volume therein to accommodate said treatment device (211, 311, 411).

10. The discharge system (200, 300, 301, 400) as claimed in claim 9, wherein said first portion (206) includes a first bend (240), said first sub-member (221) is disposed substantially upward with respect to said second sub-member (222), said first sub-member (221) having a first radius of curvature (231) for forming said first bend (240) and said second sub-member (222) includes a second radius of curvature (232) for forming said first bend (240), and said second radius of curvature (232) substantially greater than said first radius of curvature (231).

11. The discharge system (200) as claimed in claim 1, wherein said discharge pipe (205) includes one or more bends (240), said treatment device (211) disposed substantially between a first bend (240) and a second bend thereof.

12. The discharge system (200, 300, 301, 400) as claimed in claim 1, wherein the first portion (206, 306, 406) includes a flange member (223, 323, 423) provided at said first-upstream end portion (208, 308), said flange member (223, 323, 423) at least partially holding a first sub-member (221, 321, 421) and a second sub member (222, 322, 422) of said first portion (206, 306, 406), wherein said flange portion (223, 323, 423) includes a cylindrical upstream end adapted to engage with an exhaust port (184) of the power unit (125).

13. The discharge system (200) as claimed in claim 8, wherein first sub-member (221) and said second sub-member (222) are having a first radius of curvature (231) and a second radius of curvature (232) respectively, taken at an angular portion of a first bend 240 of said first portion (206), and a ratio of said second radius of curvature (232) to said first radius of curvature (231) is in the range of 3 to 8.

14. The discharge system (200) as claimed in claim 1, wherein the first portion (206), subsequent to a first bend (240), is having an upper circumferential portion (226) disposed at a first distance (235) from an imaginary horizontal line (236) passing through said first-upstream end portion (208) of said first portion (206), and a lower circumferential portion (227) disposed at a second distance (237) from the imaginary horizontal line (236) passing through said first-upstream end portion (208) of said first portion (206).

15. A discharge system (300, 301, 400) for a motor vehicle (100), said discharge system (300, 301, 400) connected to a power unit (125) of said motor vehicle (100), the discharge system (300, 301, 400) comprising:

a discharge pipe (305, 405), said discharge pipe (305, 405) formed by a first portion (306, 406) and a second portion (307, 407), said first portion (306. 407) connected to an exhaust port (184) of said power unit (125) through a first-upstream end portion (308, 408) thereof, said second portion (307, 407) disposed downstream of said first portion (306, 406), one of said first portion (306, 406) and said second portion (307, 407) being adapted to support a treatment device (311, 411),

said first portion (306, 407) capable of at least partially annularly enclosing said treatment device (311, 411), and said first portion (306, 406) includes a first-downstream end portion secured to said second portion (307), and

said treatment device (311, 411) includes a substrate (313, 413) supported by a sleeve (312, 412) thereof, said sleeve (312, 412) is configured to support a sensor member (345) disposed upstream to said substrate (313, 413).

16. The discharge system (300, 301, 400) as claimed in claim 15, wherein said sleeve (312, 412) of said treatment device (311) includes an upstream-extended portion (314, 414) provided on an upstream end thereof, and said sensor member (345) is secured at said upstream-extended portion (314, 414)

17. The discharge system (300, 301, 400) as claimed in claim 15, wherein said sensor member (345) is secured to a mounting bracket (350), and said mounting bracket (350) is secured to said upstream-extended portion (314, 414) through an aperture (355, 455) formed on said first portion (306, 406).

18. The discharge system (300, 301, 400) as claimed in claim 17, wherein said aperture (355, 455) includes an inward edge (356), said inward edge (356) annularly surrounding said mounting bracket (350) is bent inward to abut an outer periphery of said sleeve (312, 412).

19. A discharge system (400) for a motor vehicle (100), said discharge system (400) connected to a power unit (125) of said motor vehicle (100), the discharge system (400) comprising:

a discharge pipe (405), said discharge pipe (405) formed by a first portion (406) and a second portion (407), said first portion (406) connected to an exhaust port (184) of said power unit (125) through a first-upstream end portion (408) thereof, said second portion (407) disposed downstream of said first portion (406), one of said first portion (406) and said second portion (407) being adapted to support a treatment device (411),

said first portion (406) capable of at least partially annularly enclosing said treatment device (411), and said first portion (406) includes a first- downstream end portion secured to said second portion (407), and wherein at least one resistance member (465, 466) mounted to said treatment device (411).

20. The discharge system (400) as claimed in claim 19, wherein said at least one resistance member includes one or more first resistance member(s) (465) mounted to a sleeve (412) at an upstream portion of a substrate (413) supported by said treatment device (411), and said first resistance member (465) includes plurality of perforations.

21. The discharge system (400) as claimed in claim 19, wherein said at least one resistance member includes one or more second resistance member(s) (466) mounted to a sleeve (412) at a downstream portion of a substrate (413) supported by said treatment device (411), and said second resistance member (466) includes plurality of perforations.

22. The discharge system (400) as claimed in claim 19, wherein said treatment device (411) is provided with a stopper plate (480) provided at the downstream end thereof, and said second resistance member(s) (466) provided with plurality of perforations formed radially on said sleeve (412).

23. The discharge system (200) as claimed in claim 19, wherein said at least one resistance member (465, 466) includes perforations having an overall area in the range of 50-150% of an area of a frontal area of said treatment device (411).