TECHNICAL FIELD

[0001] The present subject matter relates generally to fuel supply system for three wheeled vehicles and more particularly, but not exclusively, to evaporative emission control system for three wheeled vehicles.

BACKGROUND

[0002] Generally, internal combustion (IC) engines require air intake, fuel, and spark ignition to achieve combustion. Atmospheric air is drawn in when a vacuum is created in cylinders during an intake stroke of the IC engine. Further, the atmospheric pressure outside also ensures that air is available as and when required by the IC engines. The air that is drawn in is appropriately mixed with the fuel from a fuel storage device, for example, a fuel tank, and the resulting air-fuel mixture is supplied to combustion chamber of the IC engine. A system that controls the air drawn in and the air supplied to the IC engine for combustion is commonly referred to as an air intake system, while a system that controls the fuel supplied to the IC engine is referred to as fuel supply system.

[0003] Generally, the fuel supply system of IC engines includes the fuel tank, a fuel pump, a fuel filter, plurality of hoses for routing fuel to the IC engine, and optionally a fuel injecting device for injecting the air-fuel mixture into an intake manifold of said IC engine.

[0004] For example, in case of spark ignition IC engines using gasoline or petrol as fuel, the fuel supply system is further enabled to control evaporative emissions. Generally, evaporative emission is caused by direct evaporation of hydrocarbon vapours from the plurality of components of the fuel supply system. Recently, the evaporative emission control system, also called as 'EVAP' gained significance after the introduction of regulations insisting for norms on evaporative emission across the globe.

[0005] Generally, such evaporative emissions caused due to direction evaporation of hydrocarbon vapours leads to smog formation, which have a direct impact on health effects. For example, formation of smog may cause damage to human respiratory system by causing choking, coughing, and by reducing lung capacity.

[0006] Conventionally, hydrocarbon evaporation from automobiles are caused due to a plurality of losses, for example, diurnal breathing loss that is caused due to variation in ambient temperature, hot soak loss that is caused due to transfer of heat from high temperature zones of an automobile such as an 1C engine, especially when the vehicle is kept in parked condition after an end of a trip. Similar losses known in the art also includes running losses, which are due to generation of vapours when the IC engine is in running condition, and refuelling losses, that causes fuel vapours from the fuel tank to escape into the atmosphere during the process of refuelling of the fuel tank.

[0007] Conventional evaporative emission control measures are affected by various factors such as design of vehicle and particularly fuel supply system of the vehicle, variation in ambient temperature, volatility of gasoline, and other reasons including average trip distance, parking time, parking location, duration of parking under direct sunlight etc.

[0008] Generally, automobiles, in particular, four-wheeled vehicles are known to contain an EVAP system that prevents escape of hydrocarbon vapours into the atmosphere both during vehicle running and parking conditions. For example, such systems enable collection of emitted fuel vapours from the fuel tank followed by re-burning of collected fuel vapours by transmitting the fuel vapours to the IC engine so as to prevent atmospheric pollution caused due to emission of such hydrocarbon vapours. Generally known techniques of adsorption of emitted hydrocarbon vapors include use of devices such as a canister that contains activated carbon.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[00010] FIG. 1 illustrates a perspective view of a frame structure of a three-wheeled vehicle, in accordance with an embodiment of the present subject matter.

[00011] FIG. 2 illustrates a rear view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system in accordance with an embodiment of the present subject matter.

[00012] FIG. 3 illustrates a rear view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system in accordance with another embodiment of the present subject matter.
[00013] FIG. 4 illustrates a rear view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system in accordance with yet another embodiment of the present subject matter.

[00014] FIG. 5 illustrates a perspective view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system in accordance with a further embodiment of the present subject matter.

DETAILED DESCRIPTION

[00015] Generally, the EVAP system prevents the escape of fuel vapors to the atmosphere under hot soak and even during engine off conditions by storing the fuel vapors in a fuel adsorbing device, typically known as canister. The system also controls the purging of the stored fuel vapors from the canister to the engine, where they are further burned in the combustion chamber and thereby enabling effective combustion of fuel.

[00016] Typically, canisters are devices found in automobiles enabling decrease of the amount of air pollution the vehicle creates while at the same time helping in enhancing the fuel efficiency of the vehicle. Even when the vehicle's engine is turned off, a certain minimal quantity of hydrocarbon in the form fuel vapors are produced. The canisters trap the fuel vapors rising out of the fuel tank rather than allow it to escape to the atmosphere. Further, the canisters are provided with features that enable them to feed the adsorbed fuel vapors back into the engine for further combustion.

[00017] The canister is characteristic of storing fuel vapors escaping out of the stored fuel inside the fuel tank during engine-off and engine-running conditions. For example, the same is achieved when the activated carbon particles stored inside the canister adsorbs the fuel vapors escaping from the fuel tank. After adsorption of fuel vapors, any quantity of air inside the canister is vented out to the atmosphere through a vent provided on the surface of the canister body.

[00018] The canister is generally capable of storing fuel vapors for as long as required till a point they are purged out to the engine for further combustion. For example, during a suction stroke of the 1C engine, the sudden suction created along the intake manifold of the IC engine causes purging of fuel vapors out from the canister and towards the IC engine for further burning. During purging, atmospheric air at ambient condition enters the canister through the vent provided on the surface of the canister body and carries the adsorbed hydrocarbon particles from the activated carbon.

[00019] Typically, working and performance of canisters are largely influenced by the design of vehicle that includes the layout of fuel supply system, in particular, the layout provided specifically keeping in mind the location and positioning of evaporative emission control system including canister of the fuel supply system in the vehicle. Most often, optimizing the location and position of the evaporative emission control system layout enables effective emission control and enhancing the fuel efficiency.

[00020] Further, providing an optimal location and position for the evaporative emission control system in the vehicle layout also ensures that the evaporative emission control system is not affected due to day to day variations in ambient temperature.

[00021] Furthermore, providing an optimal location and position of the elements of the evaporative emission control system, for example, the canister becomes increasingly important, as mounting the canister in very low temperature zones in the vehicle cabin may impact the proper functioning of the canister. For instance, very low temperature zones may lead to ineffective purging of fuel vapors from the canister when the suction is initiated in the intake manifold of the IC engine. Further, mounting the canister in such zones also means that the size or capacity of the canister can be less optimized and often are kept higher than required, which in turn increases the bulkiness of the evaporative emission control system in the vehicle layout. Furthermore, ineffective purging may lead to more emissions arising out of the system leading to the aforementioned problems.

[00022] The present subject matter provides an optimal location and positioning of the elements of the evaporative emission control system including the canister inside the vehicle layout and enable overcoming the above mentioned problems associated with mounting the canister in very low temperature zones. Further, the present subject matter, in particular, provides an optimal location and positioning of the canister ensuring mounting of the canister in moderate temperature zones ensuring effective purging of fuel vapors from the canister to the intake manifold of the IC engine when the suction of fuel is initiated, for example, by an engine control module of the vehicle. The same is achieved by ensuring that the canister is mounted in the vicinity of the IC engine, in particular, towards a top portion of the IC engine in the vicinity of intake manifold.

[00023] In an embodiment, mounting the canister in moderately high temperature zones is possible by positioning the canister and the other devices of the evaporative emission control system in appropriate location inside the vehicle layout. For example, positioning the canister in the vicinity of the IC engine helps in ensuring the canister remains in moderately high temperature zones. In an embodiment, in the vehicle layout, for example, in a layout of a three-wheeled vehicle, the IC engine is located rearwardly of the seat base middle and the fuel tank inside the cabin assembly of the three-wheeled vehicle, when viewed from rear of the three-wheeled vehicle.

[00024] In one implementation, the canister is mounted on the vicinity of the IC engine and farther away from the fuel tank in a substantially upwardly rightward with respect to the position of the IC engine when viewed from the rear side of the three-wheeled vehicle. In another implementation, the canister is capable of being mounted or substantially upwardly leftward of the IC engine when viewed from the rear side of the three-wheeled vehicle.

[00025] In an embodiment, the evaporative emission control system for a three-wheeled vehicle of the present subject matter includes an internal combustion engine that is mounted rearwardly of the three-wheel vehicle. The engine is disposed in a space substantially downwardly of one or more cabin mounting towers. In an implementation, the cabin mounting towers are U-shaped structural members that are mounted on longitudinal members of the three-wheeled vehicle frame. In one embodiment, the engine is substantially mounted between the two longitudinal members of the three-wheeled vehicle. Further, in one embodiment, the engine in the vehicle layout provided by the present subject matter is mounted substantially rearwardly of at least one cross member, which is disposed transversely to a longitudinal axis of the threes-wheeled vehicle. Furthermore, in one embodiment, the engine of the present subject matter is mounted substantially rearwardly of an upwardly disposed frame member, for example, a seat base middle.

[00026] Further, in an embodiment, the control system further includes a fuel tank disposed substantially rearwardly of the seat base middle. In an implementation, the fuel tank is disposed substantially forwardly of the one or more cabin mounting towers.

[00027] In one embodiment, the evaporative emission control system further includes an evaporative emission control device; for example, the evaporative emission control device is a canister. In one embodiment, the canister enables treating of fuel vapors expelling from the fuel tank disposed substantially upward of the engine in a vicinity of the fuel tank. Further, in an embodiment, the canister is disposed substantially upward and in a vicinity of at least a top portion of the engine and farther away from the fuel tank. In particular, the canister is disposed in at least one of a substantially upwardly rightward, and substantially upwardly leftward of the engine.

[00028] In an embodiment, an air cleaner is mounted on the at least one vertical member of the seat base middle. The longitudinal axis of the air cleaner extends in a vehicle width direction. Further, the canister is mounted on at least a surface of the air cleaner. The longitudinal axis of the control device is displaced

substantially parallel to a ground surface in a vehicle width direction. The control device is disposed substantially upwardly rightward of the engine.

[00029] In one embodiment, at least a transistorized coil ignition (TCI) cover is mounted on the at least one vertical member of the seat base middle adjoining the air cleaner. The longitudinal axis of the air cleaner extends in a vehicle width direction. The canister is mounted on at least a surface of the TCI cover. The longitudinal axis of the canister is displaced substantially parallel to a ground surface in a vehicle width direction. Further, the canister is disposed substantially upwardly leftward of the engine.

[00030] In another embodiment, the canister is mounted on at least one boss disposed on a top portion of an intake manifold of the internal combustion engine. The longitudinal axis of the control device is displaced substantially inclined to a lateral axis of the vehicle that is parallel to a ground surface in a vehicle width direction. The canister is disposed substantially upward of the engine.

[00031] In another embodiment, the canister is mounted on at least one mounting bracket provided on an engine cowl disposed on a top portion of the internal combustion engine. The longitudinal axis of the canister is displaced substantially along a lateral axis of the vehicle that is parallel to a ground surface in a vehicle width direction. The canister is disposed substantially upwardly leftward of the engine.

[00032] Further, in one embodiment, the evaporative emission control system further includes at least one roll-over valve for receiving fuel vapors expelling from the fuel tank through at least a first hose connecting the fuel tank to the roll-over valve. The roll-over valve prevents passage of fuel along with the fuel vapors. Furthermore, the fuel vapors exiting out of the roll-over valve is expelled to the canister through at least a second hose connecting the roll-over valve to the canister.

[00033] Furthermore, in one embodiment, the fuel vapors from the canister are collected by at least a purge valve through at; least a third hose connecting the canister to the purge valve. In an embodiment, the purge valve pulls the fuel from the canister during a suction stroke of the internal combustion engine and transfers to the internal combustion engine through at least a fourth hose.

[00034] The present subject matter and its equivalent thereof offer many advantages, including those, which have been described henceforth. The evaporative emission control system of the present subject matter provides an optimal location and positioning of the canister and the other cooperative components of the evaporative emission control system including roll-over valve and purge valve. Further, the positioning of the components of the evaporative emission control system in optimal location, enables the vehicle layout to achieve effective and improved purging of the fuel stored in the canister, which influences an enhanced fuel efficiency and reduced emission levels. Furthermore, the positioning of the canister around the vicinity of the engine ensures no stagnaton of fuel or fuel vapor inside the canister. Moreover, the optimal location of the canister mounting is achieved without modifying the existing components in the cabin assembly of the three-wheeled vehicle. Furthermore, the optimized location of the canister also ensures that the size or capacity of the canister is optimal and not bulky. This helps in optimally accomodating the canister inside the vehicle cabin.

[00035] These and other advantages of the present subject matter would be described in greater detail in conjunction with the figures in the following description.

[00036] FIG. 1 illustrates a perspective view of a frame structure of a three-wheeled vehicle, in accordance with an embodiment of the present subject matter. The frame structure 100 of the three-wheeled vehicle depicts a chassis 124 of the three-wheeled vehicle that includes a cabin assembly 112 on the rear side of the three-wheeled vehicle. In an embodiment, the frame structure 100 of the three-wheeled vehicle includes three compartments. A front compartment including a head tube 128 that mounts a handle bar assembly (not shown) of the three-wheeled vehicle, a main tube 126 that connects the head tube 128 and the chassis 124 and a driver seat assembly (not shown) that is housed on top of the chassis 124. In one embodiment, the frame structure 100 further includes a middle compartment that includes a seat base bottom housed on top of a plurality of longitudinal members 118. The seat base bottom of the middle compartment generally enables seating of passengers or occupants of the three-wheeled vehicle. Further, in one embodiment, the frame structure 100 also includes a rear compartment that houses the cabin assembly 112.

[00037] In one embodiment, the cabin assembly 112 of the present subject matter houses an internal combustion (IC) engine 102 and the other driving components of the three-wheeled vehicle. In an embodiment, the IC engine 102 is a spark ignition engine. Further, in one embodiment, the cabin assembly 112 includes a fuel tank 108 disposed upwardly leftward of the cabin assembly 112 when viewed from the rearside of the three-wheeled vehicle. [00038] In an embodiment, the evaporative emission control system of the present subject matter includes other ancillary components that are functionally interconnected with the fuel tank 108. These components include the canister (not shown). In an embodiment, the canister is mounted in the vicinity of the fuel tank 108. In an embodiment, the monting location and positioning of the canister impacts the evaporative emission control system of the present subject matter. Further, the cabin assembly 112 also includes an air cleaner 106 disposed upwardly and rightward of the IC engine 102.

[00039] In one embodiment, the cabin assembly 112 includes the longitudinal members 118 extending on both left and right sides of the cabin. In an embodiment, the cabin assembly 112 further includes a cabin mounting tower including at least one horizontal member 110 and one or more vertical members 116. For example, the one or more vertical members 116 extends vertically upwardly from the top surface of the one or more longitudinal members 118. The top ends of the vertical members 116 are connected by at least one horizontal member 110. In an embodiment, the seat base bottom of the middle compartment has an elongated member that extends inside the cabin assembly 112. The elongated member is a seat base middle 114.

[00040] In an embodiment, the fuel tank 108 and the air cleaner 106 are disposed on both left and right ends of the cabin assembly 112 respectively between the seat base middle 114 and the cabin mounting towers 110, 116. In one embodiment, the one or more longitudinal members 118 of the cabin assembly are horizontally connected by at least one cross member 122. Further, in one embodiemnt, the IC engine 102 is disposed underneath the horizontal member 110 of the one or more cabin mounting towers 110, 116 and placed in the space available between the two longitudinal members 118. In one embodiment, the IC engine 102 is located rearwardly of the cross member 122.

[00041] FIG. 2 illustrates a rear view of the cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system 200 in accordance with an embodiment of the present subject matter. In one embodiment, the evaporative emission control system 200 includes an evaporative emission control device, for example, a canister 212 is optimally located in the vicinity of the IC engine 202. For instance, the canister 212 is disposed upwardly to the IC engine 202 and rightwardly to the fuel tank 208 when viewed from the rearside of the three-wheeled vehicle.

[00042] In one embodiment, the canister 212 is mounted on an air cleaner 206. In particular, the canister 212 is mounted externally on a vertical surface of the air cleaner 206 extending rearward towards the IC engine 202 in a direction that is substantially parallel to the ground surface and disposed with its longitudinal axis extending in vehicle width direction. Such a mounting location of the canister 212 enable effective purging of the fuel from the canister 212 and the optimal location further enhances ease of assembly of the fuel supply system components. [00043] In an embodiment, the fuel vapors escaping out of the fuel tank 208 are routed to a roll-over valve 216 through a first hose 214, for example, a hose connecting the fuel tank and the roll-over valve 216. The roll-over valve 216 is a one-way valve that prevents the passage of fuel further downstream into the canister 212 and allowing only fuel vapors to pass-by. In an embodiment, the roll¬over valve 216 is mounted on to a horizontal member of the cabin mounting tower 210 that is adjacent to the fuel tank 208.

[00044] Further, in one embodiment, the fuel vapors from the roll-over valve 216 are transmitted to the canister 212 through |a second hose 218, for example, a hose connecting the roll-over valve 216 and the canister 212. In an embodiment, the canister 212 contains activated carbon that adsorbs the fuel vapors entering the canister 212. The positioning of the canister 212 adjoining the fuel tank 208 enables effective adsorption of escaping fuel vapors by the canister 212.

[00045] In one embodiment, when the IC engine 202 begins suction of fuel, a purge valve 222, for example, a solenoid valve is activated for collection of fuel vapors from the canister 212. During this stage, the fuel vapors stored in the canister 212 are transmitted by an ambient air that is allowed to enter the canister 212 through at least one vent that is provided on the outer surface of the canister 212. The fuel vapors are carried by the incoming ambient air from the canister 212 through a third hose 220 that connects the canister 212 and the purge valve 222. The purge valve 222 opens up and pulls all the fuel vapors out of the canister 212 and sends across to an intake manifold of the IC engine 202 for futher combustion. In an embodiment, the fuel vapors are sent to the IC engine 202 from the purge valve 222 through a fourth hose 224'that connects the purge valve 222 and the engine 202, for example, to a carburettor 204. In one embodiment, the fuel from the purge valve 222 is sent as a .mixture of both fuel vapors and fuel as a result of cooling of incoming fuel vapors at the purge valve 222. In another embodiment, an engine control module (not shown) controls the opening and closing of the purge valve 222 depending on the suction created along the intake manifold of the IC engine 202.

[00046] FIG. 3 illustrates a rear view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system 300 in accordance with another embodiment of the present subject matter. In one embodiment, the evaporative emission control system 300 includes an evaporative emission control device, for example, a canister 312 that is optimally located in the vicinity of the IC engine 302. For instance, the canister 312 is disposed upwardly to the IC engine 302 and rightwardly to the fuel tank 308 when viewed from the rearside of the three-wheeled vehicle.

[00047] In one embodiment, the canister 312 is mounted on a rearwardly disposed surface of a TCI cover 328. For example, the canister 312 is mounted on a rearward surface of the TCI cover 328 that is facing the IC engine 302. In particular, the canister 312 is mounted on the rearward facing surface of the TCI cover 328 in a direction that is substantially parallel to the ground surface and disposed with its longitudinal axis extending in vehicle width direction. Such a mounting location of the canister 312 enable effective purging of the fuel from the canister 312 and the optimal location further enhances serviceability of the fuel supply system components.

[00048] In an embodiment, the fuel vapors escaping out of the fuel tank 308 are routed to a roll-over valve 316 through a first hose 314, for example, a hose connecting the fuel tank and the roll-over valve 316. The roll-over valve 316 is a one-way valve that prevents the passage of fuel further downstream into the canister 312 and allowing only fuel vapors to pass-by.

[00049] Further, in one embodiment, the fuel vapors from the roll-over valve 316 are transmitted to the canister 312 through a second hose 318, for example, a hose connecting the roll-over valve 316 and the canister 312. In an embodiment, the canister 312 contains activated carbon that adsorbs the fuel vapors entering the canister 312. The positioning of the canister 312 adjoining the fuel tank 308 enables effective adsorption of escaping fuel vapors by the canister 312.

[00050] In one embodiment, when the IC engine 302 begins suction of fuel, a purge valve 322, for example, a solenoid valve is activated for collection of fuel vapors from the canister 312. During this stage, the fuel vapors stored in the canister 312 are transmitted by an ambient air that is allowed to enter the canister 312 through at least one vent that is provided on the outer surface of the canister 312. The fuel vapors are carried by the incoming ambient air from the canister 312 through a third hose 320 that connects the canister 312 and the purge valve 322. The purge valve 322 opens up and pulls all the fuel vapors out of the canister 312 and sends across to an intake manifold of the IC engine 302 for futher combustion. In an embodiment, the fuel vapors are sent to the IC engine 302 from the purge valve 322 through a fourth hose 324 that connects the purge valve 322 and the engine 302, for example, to a carburettor 304. In one embodiment, the fuel from the purge valve 322 is sent as a mixture of both fuel vapors and fuel as a result of cooling of incoming fuel vapors at the purge valve 322.

[00051] FIG. 4 illustrates a rear view of a cabin assembly of a three-wheeled vehicle depicting an evaporative emission control system 400 in accordance with yet another embodiment of the present subject matter. In one embodiment, the evaporative emission control system 400 includes an evaporative emission control device, for example, a canister 412 is optimally located in the vicinity of the IC engine 402. For instance, the canister 412 is disposed upwardly to the IC engine 402 and rightwardly to a fuel tank 408 when viewed from the rearside of the three-wheeled vehicle.

[00052] In one embodiment, the canister 412 is mounted on an intake manifold 430 of the IC engine 402. In particular, the canister 412 is mounted on the intake manifold 430 at by means of a mounting bracket (not shown) fixed to the intake manifold 430 in a direction that is substantially inclined to a lateral axis of the vehicle that is parallel to the ground surface in a vehicle width direction. Further, the canister 412 is disposed rightwardly to the fuel tank 408 when viewed from the rearside of the three-wheeled vehicle. Furthermore, the canister 412 is disposed downwardly leftward to the air cleaner 406 when viewed from the rearside of the three-wheeled vehicle. Such a mounting location of the canister 412 enable effective purging and the optimal location further enhances serviceability and ease of assembly of the components of the fuel supply system within the cabin assembly.

[00053] In an embodiment, the fuel vapors escaping out of the fuel tank 408 are routed to a roll-over valve 416 through a first hose 414, for example, a hose connecting the fuel tank and the roll-over valve. The roll-over valve is a one-way valve that prevents the passage of fuel further downstream into the canister 412 and allowing only fuel vapors to pass-by.

[00054] Further, in one embodiment, the fuel vapors from the roll-over valve are transmitted to the canister 412 through a second hose 418, for example, a hose connecting the roll-over valve 416 and the canister 412. In an embodiment, the canister 412 contains activated carbon that adsorbs the fuel vapors entering the canister 412. The positioning of the canister 412 adjoining the fuel tank 408 enables effective adsorption of escaping fuel vapors by the canister 412.

[00055] In one embodiment, when the IC engine 402 begins suction of fuel, a purge valve 422, for example, a solenoid valve is activated for collection of fuel vapors from the canister 412. During this stage, the fuel vapors stored in the canister 412 are transmitted by an ambient air that is allowed to enter the canister 412 through at least one vent that is provided on the outer surface of the canister 412. The fuel vapors are carried by the incoming ambient air from the canister 412 through a third hose 420 that connects the canister 412 and the purge valve 422. The purge valve 422 opens up and pulls all the fuel vapors out of the canister 412 and sends across to an intake manifold of the IC engine 402 for futher combustion. In an embodiment, the fuel vapors are sent to the IC engine 402 from the purge valve 422 through a fourth hose 424 that connects the purge valve 422 and the engine 402, for example, to a carburettor 404. In one embodiment, the fuel from the purge valve 422 is sent as a mixture of both fuel vapors and fuel as a result of cooling of incoming fuel vapors at the purge valve 422.

[00056] FIG. 5 illustrates a perspective view of a cabin assembly of a three-wheeled vehicle depicting an evaporative dmission control system 500 in accordance with a further embodiment of the present subject matter. In one embodiment, the evaporative emission control system 500 includes an evaporative emission control device, for example, a canister 512 is optimally located in the vicinity of the IC engine 502. For instance, the canister 512 is disposed rearwardly to the IC engine 502 when viewed from the rearside of the three-wheeled vehicle and forwardly to the IC engine 502 with respect to the vehicle front..

[00057] In one embodiment, the canister 512 is mounted on an engine cowl 530. In particular, the canister 512 is mounted on slanting surface of the engine cowl 530 that is extending downwardly forward from a top portion of the IC engine 502. In an embodiment, the canister 512 is mounted in a direction that is substantially parallel to the ground surface and disposed with its longitudinal axis extending in vehicle width direction. In one embodiment, the canister 512 is disposed downwardly to a TCI cover 528, downwardly leftward to an air cleaner 506 and downwardly rightward to a fuel tank 508 when viewed from the rear side of the three-wheeled vehicle. Such a mounting location of the canister 512 enable improved purging of the fuel out of the canister 512 and the optimal location further enhances serviceability of the fuel supply system components.

[00058] In an embodiment, the fuel vapors escaping out of the fuel tank 508 are routed to a roll-over valve 516 through a first hose 514, for example, a hose connecting the fuel tank and the roll-over valve 516. The roll-over valve 516 is a one-way valve that prevents the passage of fuel further downstream into the canister 512 and allowing only fuel vapors to pass-by.

[00059] Further, in one embodiment, the fuel vapors from the roll-over valve 516 are transmitted to the canister 512 through a second hose 518, for example, a hose connecting the roll-over valve 516 and the canister 512. In an embodiment, the canister 512 contains activated carbon that adsorbs the fuel vapors entering the canister 512. The positioning of the canister 512 adjoining the fuel tank 508 enables effective adsorption of escaping fuel vapors by the canister 512.

[00060] In one embodiment, when the IC engine 502 begins suction of fuel, a purge valve 522, for example, a solenoid valve is activated for collection of fuel vapors from the canister 512. During this stage, the fuel vapors stored in the canister 512 are transmitted by an ambient air that is allowed to enter the canister 512 through at least one vent that is provided on the outer surface of the canister 512. The fuel vapors are carried by the incoming ambient air from the canister 512 through a third hose 520 that connects the canister 512 and the purge valve 522. The purge valve 522 opens up and pulls all the fuel vapors out of the canister 512 and sends across to an intake manifold of the IC engine 502 for futlier combustion. In an embodiment, the fuel vapors are sent to the IC engine 502 from the purge valve 522 through a fourth hose 524 that connects the purge valve 522 and the engine 502, for example, to a carburettor 504. In one embodiment, the fuel from the purge valve 522 is sent as a mixture of both fuel vapors and fuel as a result of cooling of incoming fuel vapors at the purge valve 522.

[00061] Although the subject matter has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. It is to be understood that the appended claims are not necessarily limited to the features described herein. Rather, the features are disclosed as embodiments of the frame structure 100 of the three-wheeled vehicle and the evaporative emission control system 200, 300,400, and 500.

1/ we claim:

1. An evaporative emission control system (200, 300, 400, 500) for a three-
wheeled vehicle comprising:
an internal combustion engine (102) mounted rearwardly of said vehicle, said engine (102) disposed in a space substantially downwardly of one or more cabin mounting towers (110, 116), substantially between two longitudinal members (118) of said vehicle, substantially rearwardly of at least one cross member (122) disposed transversely to a longitudinal axis of said vehicle, and substantially rearwardly of an upwardly disposed frame member (114) of said vehicle;
a fuel tank (108) disposed substantially rearwardly of said upwardly disposed frame member (114), and substantially forwardly of said one or more cabin mounting towers (110, 116); and
an evaporative emission control device (212, 312, 412, 512) for treating fuel vapors expelling from said fuel tank (108) disposed substantially upward and in a vicinity of at least a top portion of said engine (102) and farther away from said fuel tank (108), wherein said control device (212, 312, 412, 512) is disposed in at least one of a substantially upwardly rightward, and substantially upwardly leftward of said engine (102) when viewed from a rear side of the three-wheeled vehicle.

2. The evaporative emission control system (200, 300, 400, 500) as claimed in claim 1, wherein said upwardly disposed frame member (114) includes a seat base middle (114) having at least one horizontal member disposed lengthwise along a vehicle width direction, and at least one vertical member connecting said at least one horizontal member of said seat base middle (114) and a longitudinal member (118) of said vehicle in a vehicle up-down direction.

3. The evaporative emission control system (200) as claimed in claim 2, further comprising an air cleaner (206) mounted on said at least one vertical member of a seat base middle (226), wherein a longitudinal axis of said air cleaner (206) extends in a vehicle width direction, and wherein said control device (212) is mounted on at least a surface of said air cleaner (206), a longitudinal axis of said control device (212) is displaced substantially parallel to a ground surface in a vehicle width direction, said control device (212) is disposed substantially upwardly rightward of said engine (202).

4. The evaporative emission control system (300) as claimed in claim 2 or 3, further comprising at least a transistorized coil ignition (TCI) cover (328) mounted on said at least one vertical member of a seat base middle (326) adjoining said air cleaner (306), wherein a longitudinal axis of said air cleaner (306) extends in a vehicle width direction, and,wherein said control device (312) is mounted on at least a surface of said TCI cover (328), a longitudinal axis of said control device (312) is displaced substantially parallel to a ground surface in a vehicle width direction, said control device (312) is disposed substantially upwardly leftward of said engine (302).

5. The evaporative emission control system (400) as claimed in claim 1, wherein said control device (412) is mounted on at least one boss disposed on a top portion of an intake manifold (430) of said IC engine (402), a longitudinal axis of said control device (412) is displaced substantially inclined to a lateral axis of said vehicle that is parallel to a ground surface in a vehicle width direction, and wherein said control device (412) is disposed substantially upward of said engine (402).

6. The evaporative emission control system (500) as claimed in claim 1, wherein said control device (512) is mounted on at least one mounting bracket provided on an engine cowl (530) disposed on a top portion of said IC engine (502), a longitudinal axis of said control device (512) is displaced substantially along a lateral axis of said vehicle that is parallel to a ground surface in a vehicle width direction, and wherein said control device (512) is disposed substantially upwardly leftward of said engine (502).

7. The evaporative emission control system (200, 300, 400, 500) as claimed in one of the preceding claims further comprising at least one roll-over valve (216) for receiving fuel vapors expelling from said fuel tank (208) through at least a first hose (214) connecting said fuel tank (208) to said roll-over valve (216), wherein said roll-over valve (216) prevents passage of fuel along with said fuel vapors.

8. The evaporative emission control system (200, 300, 400, 500) as claimed in claim 7, wherein said fuel vapors from said roll-over valve (216) is expelled to said control device (212) through at least a second hose (218) connecting said roll-over valve (216) to said control device (212).

9. The evaporative emission control system (200, 300, 400, 500) as claimed in claim 8, wherein said fuel vapors from said control device (212) is collected by at least a purge valve (222) through at least a third hose (220) connecting said control device (212) to said purge valve (222).

10. The evaporative emission control system (200, 300, 400, 500) as claimed in claim 9, wherein said purge valve (222) pulls the fuel from said control device (212) during a suction stroke of said internal combustion engine (202) and transfers to said internal combustion engine (202) through at least a fourth hose (224).