TECHNICAL FIELD [0001] The present subject matter relates generally to a power unit for a motor vehicle, and more particularly to an exhaust system for the power unit of the motor vehicle.
BACKGROUND [0002] Generally, motor vehicles with saddle-ride type layout have acquired prominence due to their compact layout. Such saddle-ride type vehicles have a structural member formed by a frame assembly or by a monocoque structure of the vehicle. Such saddle-ride type vehicles may have one front wheel with one or more rear wheels, one rear wheel with one or more front wheels, or plurality of wheels in the front and in the rear. Such vehicles are colloquially referred to as a scooter, motorcycle or trike etc. An internal combustion engine is mounted to the structural member of the vehicle. The internal combustion engine is capable of generating required amount of power or torque for driving the vehicle. [0003] These vehicles incorporating the internal combustion engine are powered by gasoline or diesel. Combustion process that takes place in the internal combustion engine is converted into mechanical energy for producing the required amount of power and torque. Also, the combustion process generates exhaust gas that is to be scavenged into the atmosphere. An exhaust system is very essential system of the vehicle as the exhaust gasses are to be carefully treated before emitting into the atmosphere. Also, the exhaust system is essential to determine the effective working of the engine.
BRIEF DESCRIPTION OF THE DRAWINGS [0004] The detailed description of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.
[0005] Fig. 1 (a) illustrates a right side view of an exemplary motor vehicle, in accordance with an embodiment of the present subject matter. [0006] Fig. 1 (b) illustrates a right side view of the power unit with an exhaust system, in accordance with the embodiment as depicted in Fig. 1 (a).

[0007] Fig.l (c) illustrates a rear perspective of the power unit with the
exhaust system, in accordance with the embodiment of Fig. 1 (b).
[0008] Fig.l (d) illustrates a front view of exhaust system, in accordance with
the embodiment of Fig. 1 (a).
[0009] Fig. 1 (e) depicts a graph drawn for torque against engine speed.
[00010] Fig. 1 (f) illustrates a top perspective view of the power unit with the
exhaust system, in accordance with the embodiment of Fig. 1 (b).
[00011] Fig. 1 (g) illustrates a side perspective view of the power unit with
selected panels, in accordance with the embodiment of Fig. 1 (a).
DETAILED DESCRIPTION [00012] Typically, in a motor vehicle with a saddle-ride type layout, the internal combustion engine is mounted to the structural member of the vehicle. Generally, the motor vehicles with the internal combustion (IC) engine fixedly mounted to the vehicle include an exhaust port disposed in a front side or a rear side of the engine. The exhaust pipes extend from the respective exhaust ports towards one lateral side of the vehicle or towards both lateral sides of the vehicle and then extend towards muffler(s). For example, the vehicle with an exhaust port disposed on a front facing side of the engine has the exhaust pipe extending forward then sideward and subsequently towards the muffler, disposed at a mid-portion/rear portion of the vehicle.
[00013] Generally, the exhaust pipe includes plurality of bends, including tight bends, by way of which free flow of exhaust gas is obstructed thereby reducing the performance of the engine. Some conventional exhaust pipes undergo substantial change in direction or change in orientation along the path that creates resistance for flow of the exhaust gas and resulting in generation of back pressure. The back pressure generally provides a negative effect on the IC engine performance by reducing the power output of the engine. Also, the back pressure is generally compensated by increasing the fuel consumption that reduces the fuel efficiency of the engine, which is undesired. Additionally, some vehicles offer poor torque at low end and mid-range of operation of the engine, which is not desired.

[00014] Also, the air-fuel mixture defines the fuel consumption and performance of the engine. Generally, a closed loop control is used to control air-fuel mixture thereby providing fuel economy and providing reduced emissions. For example, a lambda sensor is mounted to exhaust pipe to identify the oxygen concentration or concentration of other gases depending on which a control system modifies the fuel quantity. Some type of lambda sensors has an operating temperature upon reaching of which the lambda sensor is operational. Therefore, during starting condition, especially during cold start, the lambda sensor takes some time for it to reach the operational temperature. During this time, the emissions are higher as the desired temperature is not achieved which is again undesired.
[00015] Moreover, the exhaust pipe is majorly exposed to the atmosphere either in the front portion or in the side portion, which affects the functioning of the lambda sensor as quick heating cannot be achieved. During operation of the vehicle, the flowing air passing by the exhaust pipe further reduces the temperature of the exhaust pipe thereby affecting required temperature. Generally, additional casing that covers the lambda sensor may be used to retain heat thereof. However, this necessitates use of an additional component, like the casing, which increases the cost of the system. Also, use of additional component increases the assembly time. Also, addition of such components increases the weight on the exhaust pipe necessitating use of larger mounting and securing means increasing overall weight of the vehicle.
[00016] Further, the exhaust pipe being substantially exposed in a front direction and in the side direction of the vehicle, the exhaust pipe and the components mounted on it are also vulnerable to being hit by stones or other foreign particles that could damage the exhaust pipe and also the parts mounted. For example, a secondary air injection (SAI) system, an exhaust gas recirculation (EGR) system, or a turbochafger system requires connection to the exhaust side, which is preferably on the exhaust pipe. Also, during impact the exhaust pipe is damaged that could result in bending or breakage that could result in increased back pressure, or untreated emissions. If damaged, the closed loop control is also

affected as the exhaust gas gets mixed with the atmospheric air providing
inaccurate data to the control unit. Also, failure of the exhaust pipe will result in
noise pollution as the gas may not be passing through the muffler that includes
perforated tubes for suppressing/reducing the noise.
[00017] Also, the exhaust pipe is generally routed in such a way that the rider
legs are at least partially exposed to hot air from the exhaust pipe, which is the air
passing over the exhaust pipe. This results in hot air reaching the user legs
causing poor and uncomfortable riding.
[00018] Thus, there is a need for a motor vehicle with an exhaust system that
is securely and optimally routed. Also, the exhaust system should be capable of
accommodating a component port securely without the need for providing any
additional casings or covers to protect an element connected to the component
port. Also, the motor vehicle should be capable of providing controlled emissions
with reliable closed loop control.
[00019] Hence, the present subject matter provides a motor vehicle
comprising an exhaust system. The exhaust system includes an exhaust pipe
extending rearward of a rear facing side of a power unit of the motor vehicle. The
power unit is preferably Fixedly mounted to a structural member of the motor
vehicle. The exhaust pipe disposed passes through a guarded region defined by
the swinging member.
[00020] It is a feature of the present subject matter that a substantial portion
of the exhaust system is securely disposed rearward of the power unit.
[00021] It is a feature that the exhaust pipe, extending towards the muffler
assembly, is having at least a first portion substantially disposed between a power
unit and a first cross-member of the swinging member. The first lateral member
and the first cross-member, extending substantially in a lateral direction, are in
proximity to the power unit. Further, a component port is provided on the exhaust
pipe and the component port is disposed substantially between the power unit and
the first cross-member when viewed from top.
[00022] It is an aspect of the present subject matter that the exhaust port
includes a component port disposed on the first portion and the component

portion is capable of supporting along with a component working in conjunction
with the exhaust port. The exhaust port includes a component port disposed
within the guarded region when viewed from the vehicle top. It is an advantage
that the exhaust pipe disposed substantially rearward of the IC engine is protected
from damage due to stone hitting or similar foreign particles.
[00023] The exhaust pipe is substantially inward with respect to an outer
most portion of the vehicle in the lateral/width direction. Thus, the exhaust pipe
and the exhaust port are securely disposed in proximity to the center of the motor
vehicle securing it from lateral impacts.
[00024] It is another aspect of the present subject matter that the exhaust pipe
has an upstream portion and a downstream portion are having a direction of flow j
of exhaust gas substantially in a rearward direction of the motor vehicle. Thus,
the exhaust pipe is capable of providing reduced resistance for flow of the j
exhaust gas. It is an advantage that back pressure acting on the engine assembly .
is also reduced due to improved flow of the exhaust gas. It is an additional
advantage that the fuel economy of the vehicle is also improved as the amount of
fuel otherwise required to be used for compensating for the back pressure is
saved. It is yet another advantage that the air-fuel ratio can be kept optimum,
preferably towards lean side during certain operating condition. ;
[00025] It is an aspect of the present subject matter that the exhaust pipe j
extending rearward from a rearward facing side of IC engine is having a first !
i bend whereby the exhaust pipe extends downward towards the guarded region. In
one embodiment, the guarded region is formed by a cross-member of the
swinging member from the rear; at least one arm of the pair of arms the swinging
member from either of the lateral sides, and a swinging axis of the swinging
member from the front. Thus, the guarded region forms an annularly closed
region protecting the exhaust pipe from all sides.
[00026] It is an aspect that the exhaust pipe extending downward after the
first bend is also disposed at an inclination with respect to imaginary vertical line
depicting a substantial center of the vehicle. Thus, the exhaust pipe after the first
bend is inclined towards one lateral side and the exhaust pipe extends towards

other side providing ample space for a lateral arm of the exhaust pipe. It is an advantage that the exhaust pipe is provided with sufficient length that is compactly disposed in the rear portion of the vehicle.
[00027] It is another feature that the exhaust pipe includes a leading bend and a lagging bend subsequent to the first bend, wherein the portion between the leading bend and the lagging bend defines the lateral arm. The lateral arm is provided with a component port for mounting or connecting one or more components working in conjunction with the exhaust system. [00028] It is a feature that the component port is within the guarded region when viewed from vehicle top thereby securing any components mounted to the component port on the exhaust port. Thus, the exhaust system securely mounts the components without the need for additional covers that would increase weight of the system. It is an advantage that the need of covers or protectors is eliminated. Further advantage being, the assembly time is reduced as additional covers are eliminated.
[00029] It is a feature that the exhaust pipe is protected from external factors as substantial portion of the exhaust pipe is disposed rearward of the IC engine and forward of the rear suspension. Also, the exhaust pipe is covered from lateral sides by at least a portion of the structural member and at least partially by the front cowl and by the swinging member thereby providing protection from all sides.
[00030] It is a further advantage that the exhaust pipe enables quick function of the components like lambda sensor or catalytic converter that requires higher temperatures for operation. As the exhaust pipe is protected from external factors as substantial portion of the exhaust pipe is disposed rearward of the IC engine and forward of the rear suspension, the lambda sensor is substantially disposed away from air flow from directly reaching the lambda sensor. This reduces heat exchange at the region thereby enabling the lambda sensor to reach the operating temperature quickly. The lambda sensor becomes quickly operational thereby providing the desired information to the control unit for emission control. This enables in providing proper closed loop control and also

improved emission reduction. Further, the reduction of temperature of the exhaust pipe due to wind flow is also reduced/ eliminated as the exhaust pipe is substantially enclosed.
[00031] 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.
[00032] In the drawings, as and where arrows are provided, the arrows
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, and arrow RH denotes right
side, and an arrow LH denotes left side with respect to the vehicle.
[0001] Fig. 1 (a) illustrates a side view of an exemplary saddle-ride type
vehicle, for example, a motorcycle according to an embodiment of the present
subject matter. The vehicle 100 includes a structural member 105, which is a
frame member 105 that is trellis type in the depicted embodiment, and comprises
a head tube, a main frame, a sub-frame member (not shown) supported by the
main frame. In a preferred embodiment, all the portions of the frame member 105
are made of lightweight metal alloy tubes joined together in a triangular form to
reinforce and support the vehicular components. Hereinafter, the terms 'frame
member' and 'structural member' are interchangeably used. The vehicle 100
includes a front wheel 110 steered by a handlebar assembly 115 and a rear wheel
120 supported by a swinging member 125. Steering assembly includes the
handlebar assembly 115 and the front wheel 110 that are pivoted for steering
operation about the head tube disposed at the front end of the structural member
105. Further, a pair of front forks 130 connects the front wheel 110 to the handle
bar assembly 115. A fuel tank 135 is disposed rearward to the handle bar
assembly 115 and is mounted to the structural member 105.
[0002] A seat assembly 140 for a rider and a pillion (not shown) for seating
are disposed rearward to a fuel tank 135 in the mentioned order from front to rear. In one implementation, the pillion seat is disposed at an elevation with respect to the rider seat. A power unit 150 of the vehicle is mounted to the

structural member 105 and is disposed substantially below the fuel tank 135 on the front portion of the vehicle 100. The power unit 150 includes at least one of an IC engine or a traction motor. Herein, the term IC engine is interchangeably used with the term power unit.
[0003] The IC engine 150 includes an air induction system along a fuel system regulated by a carburetor or a fuel injector body or the like. Exhaust gas " generated due to combustion of air-fuel mixture in the IC engine are scavenged thereof through an exhaust system 200 that includes a muffler assembly 180 disposed at a downstream portion.
[0004] Further, the swinging member 125 along with a rear suspension
assembly 165 is supported at a rear portion thereof for pivotal motion of the swinging member 125 about the structural member 105. The rear suspension assembly 165 can be mono-shock suspension 165 or a dual-shock suspension. In general terms, the front forks 130 and the rear suspension assembly 165 acts as shock absorbers and damping members.
[0005] Further, the vehicle 100 includes a headlamp assembly 170 enclosed by at least a portion of the front cowl assembly 175, referred to cowl assembly for brevity, a tail lamp housing (not shown) housed by at least a portion of the rear cover assembly 185, and at least a pair of turn signal lamps (not shown) are disposed on either sides of the vehicle.
[00033] Fig. 1 (b) illustrates a right side view of the power unit along with the exhaust system, in accordance with the embodiment as depicted in Fig. 1 (a). Fig. 1 (c) illustrates a rear perspective view of the power unit along with the exhaust system, in accordance with the embodiment as depicted in Fig. 1 (b). The IC engine 150 is fixedly mounted to the structural member 105 (as shown in Fig. 1 (a)) of the vehicle 100. The IC engine 150 includes a crankcase 151 that is substantially having two partitions separated in a longitudinal direction F-R of the vehicle 100 and the crankcase 151 includes plurality of bosses and apertures to rotatably support a crankshaft (not shown) and other components functionally connected to the crankshaft. Further, the crankcase 151 supports a cylinder block 152A and a cylinder head 152B mounted to the cylinder block 152A. Further, a

cylinder head cover is also provided to cover valve assembly disposed on a top portion of the cylinder head 152B. The cylinder block 152A and the cylinder 152B define a cylinder portion therein and a piston (not shown) disposed in the cylinder portion is capable of have a reciprocating motion about a piston axis P-P' therein that results in the rotational motion of the crankshaft. The IC engine 150 is a multi-stroke type IC with at least one stroke dedicated for intake of air-fuel mixture and at least one stroke for scavenging the exhaust gas formed due the combustion of the air-fuel mixture.
[00034] The air-fuel mixture is supplied by a blending unit 153, herein. In the present embodiment, the blending unit includes a fuel injector that is electronically controlled. A control unit (not shown) is provided to control the fuel injection quantity & timing, and ignition related parameters like spark trigger timing etc. by taking data from various vehicle related parameters including one or more like the throttle position, the rate of change of throttle position, load on the vehicle, or a lambda sensor provided on the exhaust system 200. This data would further help in reducing emissions.
[00035] In the present embodiment, the blending unit 153 is functionally connected to the cylinder head 152B and is disposed at a first face EF of the IC engine 150 and the exhaust system 200 includes an exhaust pipe 205 connected to another face of cylinder head 152B. In a preferred implementation, the IC engine 150 is a single cylinder, parallel twin-cylinder type engine, or V-twin cylinder type engine with an intake port disposed on a front facing side EF thereof and an exhaust port 154 disposed on a rear facing side ER.
[00036] The exhaust pipe 205 is extending rearward from the cylinder head 152B and then extends downward towards the muffler assembly 180 disposed on one lateral side. In the present implementation, the muffler assembly 180 is disposed on right side of the rear wheel 120. The swinging member 125 is pivoted to the frame assembly 105. In one implementation, the swinging member is swingably connected to pair of tubes of trellis frame or to a pivot bracket of a main frame of a cradle type frame member. The swinging member 125 includes a first cross-member 126 that connects a pair of arms 125A, 125B (shown in Fig. 1

(f)) that are separated in lateral direction RH-LH and the swinging member 125 is pivotable about a swinging axis SA. The rear wheel 120 is supported and is disposed between the pair of arms 125A, 125B away from a swinging axis SA of the swinging member 125. The mono-shock suspension 165 is connected to the first cross-member 126 through one end and is connected to the structural member 105 at other end. The exhaust pipe 205 extending downward is ahead of the first cross-member 126 and the mono-shock suspension 165 and extends downwards beyond a lower point of the swinging member 125. The exhaust pipe 205 includes a component port mounted with a lambda sensor 210 that is electrically connected to the control unit (not shown) of the vehicle 100. The swinging member 125 undergoes swinging motion, and an imaginary locus IL is defined by the swinging member 125 formed by the motion of the swinging member 125 and the exhaust pipe 205 extends substantially downward beyond the lower point formed by the imaginary locus IL.
[00037] In the depicted embodiment, the exhaust pipe 205 extends rearward from a rear-facing side ER of the power unit 150. The exhaust pipe 205 includes at least a first portion substantially disposed between the power unit 105 and a first cross-member 126 of the swinging member 125 when viewed from top. A component port 206 is disposed on the First portion. The exhaust pipe 205 undergoes a first bend Bl to change the orientation of the exhaust pipe 205 in a downward direction. Subsequent to the first bend Bl the exhaust pipe 205 extends inclinedly downward to enable smooth flow of the exhaust gases therethrough. The exhaust pipe 205 after the first bend Bl is having a forwardly inclined shape, providing smooth flow of exhaust gas providing low resistance. Further, the first bend Bl provides optimum radius of curvature thereat to enable smooth flow of exhaust gas. Also, the first bend Bl enables the exhaust pipe 205 to have a compact routing thereof. Further, the exhaust pipe 205 includes one or more bends to enable routing towards upstream end of the muffler assembly 180. [00038] Furthermore, as seen in side view of the motor vehicle 100, the exhaust pipe 205 is disposed substantially rearward to engine 150. Further, as shown in Fig. 1 (a), the front cowl assembly 175 extends substantially rearward

covering the exhaust pipe 205 from sides thereby reducing hot air passing by the exhaust pipe 205 from reaching the rider.
[00039] Fig. 1 (d) depicts a front view of the exhaust system as seen from rear face of the IC engine, in accordance with the embodiment of Fig. 1 (b). The exhaust pipe 205 is having an upstream end 205U that is affixed to the exhaust port 154 of the IC engine 150. The exhaust pipe 205 extends rearward from the rearward facing side ER of the IC engine 150 and then extends in a downward direction forming a forward slope in a longitudinal direction F-R of the vehicle 100. Further, in the depicted embodiment as shown in Fig. 1 (d), the exhaust pipe 205 extending downward after the first bend Bl is also disposed at an inclination with respect to imaginary line CL depicting a substantial center of the vehicle 100. The imaginary line CL is analogous to lateral center CL of the vehicle 100 and the terms are interchangeably used. This provides the exhaust pipe 205 with sufficient length towards forming of a second bend B2. Further, the exhaust pipe 205 takes the second bend B2 and then extends in a first orientation FO, which is either to right side RH or to left side LH of the vehicle 100. In the present implementation, the muffler assembly 180 is disposed on a first lateral side RH and the second bend B2 routes the exhaust pipe towards the first lateral side RH. The first orientation FO provides a smooth change in orientation of the exhaust pipe 205 to provide optimum exhaust gas flow. Furthermore, the exhaust pipe 205 includes a third bend B3 subsequent to which the exhaust pipe 205 is oriented in line with an orientation of the upstream end of the muffler assembly 180. The portion of the exhaust pipe 205 substantially between the second bend B2 and the third bend B3 is defined as a lateral arm 205L. Major portion of the lateral arm 205L forms part of the first portion of the exhaust pipe. The lateral arm 205L is provided with the component port 206 for mounting or connecting one or more components working in conjunction with the exhaust system 200. For example, a secondary air injection outlet that injects air, an exhaust gas recirculation (EGR) inlet that receives exhaust gas, or a turbocharger system inlet that receives exhaust gas through the connection thereat. In the depicted implementation, a lambda sensor 210 is mounted at the component port 206.

[00040] Further, the component port 206 is provided on an upward facing portion of the exhaust pipe 205. The lateral arm 205L is having an arm length LI formed between the second bend B2 and the third bend B3. The length of the exhaust pipe 205 between the upstream portion 205U and the first bend Bl is about 130- 160 millimeters. Further, length of the exhaust pipe 205 between the first bend Bl and the second bend B2 is about 1.4 to 1.8 times of the length of the exhaust pipe between the upstream portion 205U and the first bend Bl. Further, the arm length LI formed between the second bend B2 and the third bend B3 is about 1.4-1.8 times of the length of the exhaust pipe upstream portion 205U and the first bend Bl. Further, the ratio of length of exhaust pipe 205 taken between upstream portion 205U and second bend B2 to the length between the second bend B2 and the third bend B3 is in the range of 1.4 to 1.8 times. [00041] Further, the exhaust system 200 is capable of providing improved lower end torque and mid-range of the operation engine 150 along with optimum higher performance. Fig. 1 (e) depicts a graphical representation of torque of the Engine 150 plotted against engine speed from low end to mid-range, which is in rotations per minute. The graph depicts a first curve CI with the aforementioned ratio substantially equal to 1. At the lower ratio, the low end to mid-range torque of the engine 150 is lower thereby offering poor performance at the low and mid-range RPM of the engine 150. As the vehicle is majorly operated in the low and mid-range, especially in the city riding conditions, the vehicle 100 offers poor performance. Further, a second curve C2 depicts the plot for the torque of the engine 150 taken at a low to mid-range of operation of the engine 150, with ration taken around 1.5. As depicted, the engine 150 offers improved performance even at the lower end speed of the engine operation. Further, a third curve C3 depicts the torque variation of the engine 150 for the aforementioned ratio taken in a value higher than 1.5, say 1.8. Thus depicts the engine 150 offers further improvement of the low-end to mid-range torque of the engine 150. The exhaust system 200 is capable of offering low-resistance path to the engine and at the same time is capable of providing improved lower-end to mid-range performance of the engine 150.

[00042] Thus, majority of the length of the exhaust pipe 205 is substantially disposed at the center of the vehicle, wherein the center is both lateral center and longitudinal center thereby enabling optimum layout of the exhaust system to achieve smooth and low resistance flow of exhaust gases, with best heat retention & minimum emission with minimum fuel consumption. Thus, the exhaust system 200 is compactly disposed close to the center of gravity (CG) of the vehicle 100. Also, in one implementation, majority of the portion of the exhaust pipe 205 is disposed at a central region formed by interjunction of a lateral center portion and a longitudinal center portion of said motor vehicle 100, whereby the exhaust pipe 205 is securely disposed in the vehicle 100.
[00043] In a preferred implementation, the lambda sensor 210 is disposed at a sensor angle with respect to direction of flow of the exhaust gas to enable optimum functioning of the lambda sensor. The senor angle is in the range of 75-105 degrees to enable optimum functioning of the sensor 210. Further, a sensor cable 211 capable of electrically connecting the lambda sensor 210 to a control unit is extending in an upward direction UP and passes through a gap formed between the arms 125A, 125B of the swinging member 125. [00044] Also, it provides the advantage of protecting of exhaust pipe 205 from external factors as substantial portion of the exhaust pipe 205 is disposed rearward of the IC engine 150 and forward of the rear suspension 165. Also, the exhaust pipe 205 is covered from lateral sides by at least a portion of the structural member 105 and at least partially by the front cowl 175 (as shown in Fig. 1 (a)) thereby providing protection from all sides. As depicted in the present embodiment, when viewed from front, the exhaust pipe 205 overlaps with at least a portion of the mono-shock suspension 165. Also, substantial portion exhaust pipe 205 is disposed between the arms 125A, 125B of the swinging member 125. Further, the motor vehicle 100 includes the advantage of having substantial portion of the exhaust pipe 205 close to the CG of the vehicle 100 thereby keeping effect of vibration minimum thereof & enhancing handling performance of the vehicle.

[00045] At the same time, the motor vehicle 100 provides ease of access to the first portion of the exhaust pipe 205 as it is being substantially disposed rearward of the engine assembly 150 and ahead of a laterally extending plane LP, depicted as dotted line, passing through one or more rear suspension 165. In the proposed embodiment, the rear suspension is a mono-shock type suspension 165 that is having an axis, which is the axis of the piston of the mono-shock type suspension, inclined forward and the plane LP is extending in a lateral direction passing through the axis. Thus, the exhaust pipe 205 is easily accessible through the gap formed between the rearward face ER of the engine assembly 150 and the plane P. Similarly, the lambda sensor 210 is also accessible from the aforementioned portion. Also, ease of maintenance is improved as the lambda sensor or the sensor cable 215 is easily accessible by service personnel. Especially, in certain vehicles as depicted in Fig. 1 (a), the front cowl assembly 175 includes side panel(s) disposed on either sides that extend towards a rear portion at least partially enclosing the engine assembly 150 and covers at least a portion of the exhaust pipe 205 from lateral side(s) RH, LH. In one embodiment, the lambda sensor 210 and the exhaust pipe 205 are accessible in a disassembled condition of the side panel(s) of the front cowl assembly 175. [00046] Further, the first portion of the exhaust pipe 205 surrounded by the guarded region GR is substantially covered by the power unit 150 from the front. Therefore, when viewed from vehicle front F, the exhaust pipe 205 from the upstream portion SU and beyond a portion the component port 206 is provided& overlapped by the IC engine 150. Thus, cooling of the exhaust pipe 205 and the ' lambda sensor 210 mounted thereat by oncoming air stream during operation of the motor vehicle 100 is substantially reduced thereby enabling early operation of the lambda sensor 210 due to quick heating. Also, a Catalytic converter (not shown) within the exhaust pipe 205 can attain early light-off thereby to due retention of the heat thereby enabling early operation of the Catalytic converter. [00047] Further, the pillion foot rest 106 is disposed at a height upwards of the exhaust pipe 205 and the exhaust pipe 205 extending in the downward

direction from the exhaust port 154 reduced or eliminates the hot air from reaching the pillion foot thereby providing comfortable ride to the pillion rider. [00048] Fig. 1 (f) depicts a top perspective view of the exhaust system connected to the power unit, in accordance with the embodiment of Fig. 1 (b). The exhaust system 200 includes the exhaust pipe 205 that is extending rearward R from a rearward facing side ER of the IC engine 150 and extends downward DW at a first bend Bl (as shown in Fig. 1 (b)). Further, the exhaust pipe 205 is extending downward from the first bend Bl and passes through a guarded region GR enclosed by the first cross-member 126 from the rear R, at least one of the pair of arms 125A, 125B of the swinging member 125 from either of the lateral sides RH, LH and a swinging axis SA disposed in the front F. A First lateral member 127 has the swinging axis SA passing through it. The lateral member 127 is either integrally formed with the swinging member 125 or is a shaft separately provided that swingably supports the swinging member 125. When viewed from top of the motor vehicle 100, the component port 206 is substantially disposed within the guarded region GR, which is preferably a quadrilateral guarded region GR forming a closed portion. The swinging axis SA, in one embodiment, is passing through the axle that swingably supports the swinging member 125. In the present embodiment, the guarded region GR is preferably a quadrilateral region GR forming a closed portion. The exhaust pipe 205 passes through the guarded region GR and subsequently extends towards the muffler assembly disposed on lateral side of the vehicle 100 by taking one or more bends B2, B3. The length between the first bend Bl and the second bend B2 is provided to keep the lateral arm 205L extending in the lateral direction downward to the swinging member 125 away from the maximum downward motion possible to the swinging member 125 thereby keeping the exhaust pipe 205 secure from any impacts from the swinging member 125. The portion of the exhaust pipe 205 between the upstream end portion SU and the third bend B3 is substantially disposed between the power unit 150 and the first cross-member 126, defining the first portion of the exhaust pipe 205.

[00049] The exhaust pipe 205 has an upstream end SU having a direction of flow of exhaust gas (depicted as dotted line) in a first direction and a downstream SD of the exhaust pipe 205 is having direction of flow of exhaust gas substantially in the first direction. Therefore, the exhaust pipe 205 enables flow of exhaust gas with reduced resistance due to reduction of substantial U-bends or L-bends having angle in-between the L-arms less than 90 degrees. Further, back pressure acting on the engine assembly 150 is also reduced. Furthermore, the fuel economy of the vehicle is also improved as the amount of fuel otherwise required to be used for compensating for the back pressure is saved. This also reduces the emissions as the air-fuel ratio can be kept optimum, preferably towards lean side during certain operating condition.
[00050] Further, the exhaust pipe 205 and the component port 206 along with a component 210 connected thereto is secured from being hit by stones or other foreign particles that could damage that part as the exhaust pipe 205 is disposed rearward of the engine assembly 150 thereby protecting the exhaust pipe 205 and the component port 206 from any damage from a front direction and a sideward direction of the exhaust pipe 205. Also, the guarded region GR securely encloses the exhaust pipe 205 substantially and during any impact the exhaust pipe 205 is protected from damage by the swinging member 125 from at least three sides. The swinging member 125 being made of a metallic member is capable of withstanding any impacts and suppressing the impact from reaching the exhaust pipe 205.
[00051] Further, Fig. 1 (g) that depicts a side perspective view of the power unit along with selected cowl assembly. The cowl assembly 175 (as shown in Fig. 1 (a)) includes a bottom cowl 176 that is disposed downward of the power unit 150 and at least a portion of the exhaust pipe 205. The bottom cowl 176 extends from rear portion of the front wheel 110 covering the power unit 150 and the exhaust pipe 205 from lateral sides Rh, LH and from bottom direction. The bottom cowl 176 extends beyond the second bend B2 whereby the bottom cowl protects the exhaust pipe 205 and the component port 206 along with the components mounted thereat from the surroundings. Further, the bottom cowl

176 includes a guide portion 177 that guides hot air from the surroundings exhaust pipe 205 in a rearward direction away from the user's feet. [00052] Furthermore, the exhaust pipe 205 is substantially inward with respect to an outer most portion of the vehicle 100 in the lateral/width direction. For example, in the present implementation, the muffler assembly 180 is having a laterally outward peripheral portion 180P substantially outward with respect to a laterally outer portion of the exhaust pipe 205. Thus, the exhaust pipe 205 is protected from any lateral impacts as the muffler assembly 180 comes first into contact with any external object thereby guarding the exhaust pipe 205. Moreover, bottom cowl 176 includes lateral member(s) 178 that are disposed on either lateral side thereof. The bottom cowl 176 includes a U-shaped cross-section covering substantial portion of the power unit 150 and the exhaust system 200 from the lateral sides and from the bottom.
[00053] 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.

We claim:
1. A motor vehicle (100) comprising:
a power unit (150) fixedly mounted to a structural member (105); an exhaust pipe (205) functionally connecting a muffler assembly (180) to said power unit (150); and
a swinging member (125) swingably connected to a structural member (105) of said motor vehicle (100),
wherein said exhaust pipe (205) extending rearward from a rear-facing side (ER) of said power unit (150) towards said muffler assembly (180), said exhaust pipe (205) includes at least a first portion substantially disposed between said power unit (105) and a first cross-member (126) of said swinging member (125) when viewed from top, and wherein a component port (206) is disposed on said first portion of said exhaust pipe (205).
2. The motor vehicle (100) as claimed in claim 1, said first portion of said exhaust pipe (205) is passing through a guarded region (GR) defined by said first cross-member (126) from the rear (R), at least one arm (125A or 125B) of said swinging member (125) extending substantially in longitudinal direction (F-R) disposed on lateral sides (RH or LH) thereof, and a first lateral member (127) with a swinging axis (SA) passing therethrough from front (F); when viewed from vehicle top.
3. The motor vehicle (100) as claimed in claim 1 or 2, wherein said component port (206) is at least partially surrounded by said guarded region (GR), when viewed from vehicle top.
4. The motor vehicle (100) as claimed in claim 1 or 2, wherein said power unit (150) includes an intake port disposed on a front-facing side (EF), and said exhaust pipe (205) is connected to an exhaust port (154) disposed on said rear-facing side (ER) of said power unit (150), said power unit (150) is rearward inclined type, and said exhaust pipe (205) is passing from an upward to downward direction through said guarded region (GR).

5. The motor vehicle (100) as claimed in claim 1, wherein said first portion of exhaust pipe (205) includes a substantially lateral arm (205L) disposed in a first orientation (FO) with respect to a lateral direction (RH-LH) of said motor vehicle (100), wherein said component port (206) is provided on said lateral arm (205L).
6. The motor vehicle (100) as claimed in claim 5, wherein said lateral arm (205L) of said exhaust pipe (205) is defined between a leading bend (B2) and a lagging bend (B3) formed thereof, said leading bend (B2) is disposed ahead of said lagging bend (B3) in a longitudinal direction (F-R) of said motor vehicle (100), and said leading bend (B2) is disposed in proximity to a lateral center (CL) of said motor vehicle (100) and said lagging bend (B3) is away from said lateral center (CL) and in proximity to an upstream portion of said muffler assembly (180).
7. The motor vehicle (100) as claimed in claim 1, claim 2or 4, wherein said exhaust pipe (205) extending rearward from said rear-facing side (ER) of said power unit (105) includes a first bend (Bl) providing a first change in orientation of said exhaust pipe (205) and subsequently said exhaust pipe (205) extends inclinedly rearward, said exhaust pipe (205) includes a second bend (B2) forming said leading bend (B2) and a third bend (B3) forming said lagging bend (B3) whereby said exhaust pipe (205) is compactly disposed rearward of said power unit (150).
8. The motor vehicle (100) as claimed in claim 1 or claim 2, wherein said exhaust pipe (205) includes an upstream portion (SU) and a downstream portion (SD), said upstream portion (SU) connected to power unit (150) and said downstream portion (SD) connected to said muffler assembly (180), wherein direction of flow of exhaust gas at said upstream portion (SU) and at said downstream portion (SD) is substantially in a rearward direction (R) of said motor vehicle (100).
9. The motor vehicle (100) as claimed in claim 6 or 7, wherein said exhaust pipe (205) post said first bend (Bl) is extending in downward direction (DW) is extending away from an imaginary vertical line (CL) forming said lateral center (CL) of said motor vehicle (100), said exhaust pipe (205) between said first bend

(Bl) and said second bend (B2) forms a portion of said first portion, whereby length of said exhaust pipe (205) between said first bend (Bl) and said second bend (B2) is compactly disposed rearward of said power unit (150) enabling smooth flow of exhaust gas therethrough.
10. The motor vehicle (100) as claimed in claim 1, claim 2 or 5, wherein said muffler assembly (180) is disposed towards one lateral side (RH or LH) of said motor vehicle (100), and said lateral arm (205L) is disposed downward of at least one arm (125A or 125B) of said swinging member (125), and said lateral arm (205L) is outside an imaginary locus (IL) formed by swinging motion of the swinging member (125).
11. The motor vehicle (100) as claimed in claim 1 or 6, wherein said power unit (150) is an internal combustion engine (150) with a piston axis (P-P') disposed at a rearward inclination, and a substantial portion of said exhaust pipe (205) formed between the first bend (Bl) and the second bend (B2) is substantially disposed at a region formed by interjunction of a lateral center portion and a longitudinal center portion of said motor vehicle (100).
12. The motor vehicle (100) as claimed in claim 1, wherein said at least a portion of said exhaust pipe (205) overlaps with at least a portion of a rear suspension (165) mounted to said cross-member (126) of said swinging member (125) when viewed from front of said vehicle (100).
13. The motor vehicle (100) as claimed in claim 1 or 2, wherein said component port (206) enables connection of at least one of a lambda sensor (210), a secondary air injection outlet, an exhaust gas recirculation (EGR) inlet, or a turbocharger system inlet thereat, and said lambda sensor (210) is disposed at a senor angle in the range of 75-105 degrees with respect to direction of flow of exhaust gases thereat.
14. The motor vehicle (100) as claimed in claim 1 or 2, wherein said lambda sensor (210) is connected to a control unit through a sensor cable (211) capable of providing electrical connection therebetween, said sensor cable (211) is extending in an upward direction (UP) passing through said guarded region (GR).

15. The motor vehicle (100) as claimed in claim 1 or claim 2, wherein said exhaust pipe (205) is substantially inward in a lateral direction (RH or LH) with respect to an outer most portion (180P) of the muffler assembly (180), and said power unit (150) is enclosed by a cowling assembly (175) in at least one direction and said cowling assembly (175, 176) is extending rearward adjacent to at least a portion of said exhaust pipe (205).
16. The motor vehicle (100) as claimed in claim 13, wherein said cowling assembly (175) includes a bottom cowl (176) extending rearward from downward portion of the power unit (150) and the exhaust pipe (205) whereby said bottom cowl (176) directs hot air rearward and protects the exhaust pipe (205) from downward impacts.
17. The motor vehicle (100) as claimed in claim 1 or claim 2, wherein the motor vehicle (100) includes a pillion foot rest (106) disposed at a height substantially upward of the exhaust pipe (205) that is extending in the downward direction (DW) from the exhaust port (154) of the power unit (150).
18. The motor vehicle (100) as claimed in claim 6, wherein said exhaust pipe (205) includes a length between the first bend (Bl) and the second bend (B2) to be in the range of 1.4 to 1.8 times of a length of the exhaust pipe (205) between the upstream portion (205U) and the first bend (Bl).
19. The motor vehicle (100) as claimed in claim 6, wherein said exhaust pipe (205) includes a length between the second bend (B2) and the third bend (B3) to be in the range of 1.4 to 1.8 times of a length of the exhaust pipe (205) between the upstream portion (205U) and the first bend (Bl).
20. The motor vehicle (100) as claimed in claim 6, wherein said exhaust pipe (205) includes a length between the upstream portion (205U) and the second bend (B2) to be 1.4 to 1.8 times the length of a length of the exhaust pipe (205) between the second bend (B2) and the third bend (B3).
21. The motor vehicle (100) as claimed in claim 2 or 6, wherein said first portion of said exhaust pipe (205) includes a portion formed between said first bend (Bl) and said second bend (B2) disposed substantially within said guarded region

(GR) when viewed from top of said vehicle (100) and said portion is passing through said guarded region (GR) from top in downward direction. 22. The motor vehicle (100) as claimed in claim 5, wherein said component port (206) is mounted to said lateral arm (205L), said component port (206) and at least a portion of said lateral arm (205L) is disposed between said guarded region (GR), when viewed from top of said vehicle (100). .