TECHNICAL FIELD
[0001] The present subject matter relates generally to a two-wheeled vehicle and more particularly to a fuel tank for the two-wheeled vehicle.
BACKGROUND
[0002] Generally, in a two-wheeled saddle-ride type vehicle a frame assembly extends rearward from a head tube. Moreover, in the two-wheeled vehicle with a step-through type frame assembly, a step-through space is provided. The frame assembly acts as a skeleton for the vehicle and supports the load carried by the . vehicle. A front portion of the frame assembly is connected to a front wheel through one or more front suspension(s). The frame assembly extends rearwardly of the vehicle, where a rear wheel is connected to the frame assembly through one or
more rear suspension(s). An internal combustion (IC) engine is mounted to the
frame assembly of the vehicle. The IC engine is functionally connected to the rear wheel, which provides the forward motion to the vehicle. Typically, plurality of panels is mounted to the frame assembly of the vehicle that cover various vehicle components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0003] The detailed description of the present subject matter is described with reference to the accompanying figures. Same numbers are used throughout the drawings to reference like features and components.
[0004] Fig. 1 (a) illustrates a left side view of an exemplary two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter. [0005] Fig. 1 (b) illustrates a top view of the two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter. [0006] Fig. 1 (c) illustrates a left side view of a frame assembly of a two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.

[0007] Fig. 2 illustrates a perspective side view of a fuel tank for the two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter.
[0008] Fig. 3 (a) depicts a sectional view of the fuel tank, taken along line A-A in Fig. 2, in accordance with an embodiment of the present subject matter. . [0009] Fig. 3 (b) illustrates a sectional view of the fuel tank, taken along line B-B in Fig. 2, in accordance with another embodiment of the present subject matter.
DETAILED DESCRIPTION [00010] Generally, in a two-wheeled vehicle with a mono-tube frame assembly, a single tubular structure extends rearwardly from the head tube towards a rear portion of the vehicle. Various vehicle components that include the engine assembly, a fuel tank, a seat assembly, and a seat assembly are mounted to the frame assembly. Generally, the vehicle has a naked appearance. Moreover, majority of the vehicle components are exposed to the atmosphere. Further, the vehicle is compactly packaged with various components. More particularly, the engine assembly is mounted to the frame assembly below the step-through space of the frame assembly. The engine assembly includes an internal combustion (IC) engine and a starter system.
[00011] Typically, in a straddle-type motorcycle, the fuel tank is disposed horizontally along a main tube axis. In such an arrangement of fuel tank, the capacity of fuel tank is typically maintained in a range of 10 to 15 litres. - [00012] More often, majority of the surface area of such tanks are exposed to direct sunlight. Further, the profile of the tank is such that, the surfaces of the tank form a rectangular box type profile, with wider center and tapering longitudinal ends. Generally, in such tanks, the width to length ratio is substantially kept at 1:3. Further, in such tanks, when the tank is filled with liquid fuel, due to continuous acceleration and deceleration of the vehicle, the fuel tends to agitate and slosh inside the tank body leading to excessive formation of fuel vapors. Such vapors,

when not controlled by separate external means, may lead to increase in
evaporative emissions into the atmosphere.
[00013] Furthermore, even when the vehicles having such tanks are in parked
condition, where there is no sloshing or agitation of liquid fuel inside the tank, there
still exists a possibility of fuel vapors escaping through the vent hole provided on
the_fuel tank cap covering the hole for filling of fuel.
[00014] Thus, there is a need to control the evaporation of fuel vapors from the
fuel tank of motorcycles, thereby reducing the atmospheric pollution and
enhancing fuel efficiency.
[00015] The present subject matter, provides a fuel tank assembly for a
motorcycle having a fuel tank body disposed substantially vertically to a ground
surface. The fuel tank body is disposed above a frame member, which obliquely
extends downwardly rearward from a head pipe of the motorcycle. The fuel tank
body has an outer profile with wider bottom and a narrower top. The fuel tank body
has a substantially U-shaped cross-section capable of being encompassing the
frame member of the motorcycle.
[00016] When viewed from a rider's seated position, the fuel tank body has a
substantially rectangular profile, with a wider bottom edge and a narrower top edge. The fuel tank body has side edges connecting the top and the bottom edges. Further, the side edges have an inclined profile tapering from the bottom edge towards the top edge. In an embodiment, the side edge" of the fuel tank body tapers ' at a position substantially below the fuel filling orifice.
[00017] The profile of the fuel tank body ensures achieving an aspect ratio of .1:2, i.e., length to width ratio of 1:2. Further, the above profile provides a larger bottom volume as compared to a top volume of the fuel tank body. In an embodiment, the volume of the tank below die tapering portion is substantially larger than the volume that is above the tapering portion.
[00018] Moreover, the orientation of the fuel tank body and die above described profile ensures that the exposure of the larger bottom volume of the fuel tank body to sunlight always remain minimum as compared to the fuel tank

assemblies of conventional straddle type motorcycles, which are oriented horizontally.
[00019] Furthermore, the position of the fuel filling orifice (or) hole on the fuel tank body of the present subject matter enables liquid fuel to be filled completely on the larger bottom volume, i.e., below the tapering portion of the fuel tank body. Further, the profile of the fuel tank body is such that, the liquid fuel doesn't get filled in the narrower top volume of the fuel tank body, i.e., above the tapering portion. Such a construction of the fuel tankbody enables any fuel vapors formed inside the fuel tank bottom volume, gets conveniently trapped (or) occupied in the narrower top volume, where there is no liquid fuel. Moreover, the fuel filling orifice is oriented substantially facing the rider in a seated position, which ensures that the fuel vapors occupying the narrower top volume do not escape through the vent provided on the fuel tank cap covering the fuel filling orifice: [00020] Further, since the cross-sectional area of the top portion of the fuel tank body is substantially lesser compared to the bottom portion, hence, the fuel vapors formed, if any, will be substantially lesser and negligible. Furthermore, the U-shaped cross-section of the bottom portion of the fuel tank body where liquid fuel is stored, in addition to the vertical orientation, do not allow sloshing and/or agitation of the liquid fuel during riding of the vehicle. This also contributes to the overall reduction in the formation of fuel vapors. Thus, ensuring negligible evaporation of the fuel vapors to the atmosphere.
[00021] The construction of the fuel tank body of the present subject matter ensures elimination of use of an alternate external means for absorbing fuel vapors. [00022] 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.
[00023] Fig. 1 (a) illustrates a left side view of an exemplary two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter. Similarly, Fig. I (b) illustrates a top view of the two-wheeled motor vehicle, in accordance with an embodiment of the present subject matter. Fig. 1 (c) illustrates a left side view of a frame assembly of a two-wheeled motor vehicle, in accordance

with an embodiment of the present subject matter. The two-wheeled vehicle 100 depicted in Fig. 1 (a) and Fig. 1 (b) includes a frame assembly 105, which acts as the skeleton for bearing the loads. The frame assembly 105 is a mono-tube type frame assembly 105 that includes a head tube 105A, a main tube 105B, a down tube 105C, and a rear tube 105D. The main tube 105B extends rearwardly downward from the head tube 105A. The down tube 105C extends rearward, along a longitudinal axis of the vehicle 100, from a rear portion of the main tube 105B. The rear tube 105D extends inclinedly rearward from a rear portion of the down tube 105C towards a rear portion R of the vehicle. A center line C-C extends along the frame assembly from a front portion towards a rear portion. The center line C-C passes substantially along the center of cross-section of the frame assembly 105. Therefore, the center line C-C extends from the head tube 105 A along the center of cross-section of the main tube 105B, then extends along the center of cross-section of the down tube 105C and along the center of the cross-section of the rear tube 105D. A handle bar assembly 115 is pivotally disposed through the head tube 105A. The handle bar assembly 115 is connected to a front wheel 110 by one or more front suspension(s) 120. A front fonder 125 is disposed above the front wheel 110.for covering at least a portion of the front wheel 110. In an embodiment, an auxiliary storage compartment is mounted to a mounting portion of the frame assembly 105. In one embodiment, the auxiliary storage compartment is a fuel tank 130, which is mounted to the main tube 105B of the frame assembly 105 and disposed in the front portion F of a step-through space of the frame assembly 105. In an alternative embodiment, the auxiliary storage compartment is a fuel tank provided with additional storage space to store accessories such as a mobile device, tools, wallet etc. In an embodiment, the additional storage space acts as a glove box. In one embodiment, the power unit 135 is mounted to the down tube 105C. In an embodiment, the power unit 135 is an IC engine. The fuel tank 130, which includes a fuel filler cap 190 for providing access to Fill fuel, is functionally connected to the power unit 135. In an embodiment, a piston axis of the engine is horizontal i.e. parallel to a longitudinal axis of the vehicle 100. A swing arm 140 is swingably connected to the frame assembly 105. A rear wheel 145 is rotatably

supported by the swing arm 140. One or more rear suspension(s) 150, which are connecting the swing arm 140 at an angle, to sustain both the radial and axial forces occurring due to wheel reaction, to the frame assembly 105. A rear fender 155 is disposed above the rear wheel 145. A seat assembly 160A, 160B is disposed at a rear portion R of the step-through space. In an embodiment, the seat assembly 160 includes a rider seat 160A, and a pillion seat 160B. Further, the seat assembly 160A, 160B is positioned above the rear wheel 145 .The vehicle is supported by a center stand mounted to the frame assembly 105. A floorboard 165 is mounted above the down tube 105C. The floorboard 165 covers at least a portion of the power unit 135.
[00024] In an embodiment, the fuel tank 130 is disposed along the main tube 105B of the frame assembly 105. The fuel tank 130 is disposed substantially inclined to a longitudinal axis 195 of the vehicle 100. The fuel tank 130 is inclined in such a manner that a top portion of the fuel tank 130 is inclined substantially forwardly towards vehicle front as compared to a bottom portion of the fuel tank 130.
[00025] The internal combustion (IC) engine of the power unit 135 includes an air'intake system (not shown), an exhaust system (not shown), and a starter system (not shown). The'starter system includes an electric starter mechanism or a mechanical starter mechanism. The electrical starter system is powered by an auxiliary power source, for cranking the IC engine. Power generated by IC engine is transferred to the rear wheel 145 through a transmission system (not shown).
[00026] Fig. 2 illustrates a perspective side view of the fuel tank 130 for the two-wheeled motor vehicle 100, in accordance with an embodiment of the present subject matter. In an embodiment, the fuel tank. 130 has a main body that is disposed along the main tube 105B of the frame assembly 105 of the vehicle 100. The main body of the fuel tank 130 has an outer surface 215 extending longitudinally along the main tube 105B. In an embodiment, the main body of the fuel tank 130 includes a LH side surface 220, and a RH side surface (not shown) extending laterally in a vehicle widthwise direction. Further, in one embodiment,

the outer surface 215 is provided with an inclinedly disposed fuel filler cap 190 towards a top portion 205 of the fuel tank 130. Furthermore, in an embodiment, the main body of the fuel tank 130 has a profile capable of achieving an aspect ratio of 1:2, i.e., length to width ratio of 1:2. Further, the above profile of the fuel tank ] 30 ensures that the volume of a bottom portion 225 of the fuel tank 130 is larger as compared to the volume of the top portion 205 of the body of the fuel tank 130. In an embodiment, the body of the fuel tank 130 includes a tapering portion substantially below the fuel filler cap 190. In an embodiment, the volume of the tank 130 below the tapering portion is substantially larger than the volume that is above the tapering portion.
[00027] Fig. 3 (a) depicts a sectional view of the fuel tank 130, taken along line A-A in Fig. 2, in accordance with an embodiment of the present subject matter. In an embodiment, the main body of the fuel tank 130 has a top volume 315 that is substantially lower than a bottom volume 325 (shown in Fig. 3 (b)). In an embodiment, the fuel tank 130 includes an inner wall top 310 that is substantially provided with a cylindrical profile converging along the LH side surface 220 and the RH side surface 305 of the main body of the fuel tank 130. Further, in an -embodiment, the fuel filler cap 190 substantially closes a fuel fill orifice 330 diat is inclinedly disposed on the top portion 205 of the main body of the fuel tank 130. [00028] Fig. 3 (b) illustrates a sectional view of the fuel tank 130, taken along line B-B in Fig. 2, in accordance with another embodiment of the present subject matter. In an embodiment, the fuel tank 130 has an inner wall bottom 320, which along with the bottom portion 224 of the outer surface 215 forms a bottom volume 325, which is substantially larger than the top volume 315. Further, in an embodiment, the bottom portion 225 has a substantially U-shaped cross-section. In an embodiment, the larger volume of the bottom portion of the main body of the fuel tank 130 as compared to the top portion along with the substantially vertical orientation of the fuel tank 130, and the side edges of the tank 130 having an inclined profile tapering from the bottom edge towards the top edge, at a position substantially below the fuel filling orifice 330, ensures that fuel vapors formed, if any, inside the fuel tank 130 will be substantially lesser- and negligible.

Furthermore, the U-shaped cross-section of the bottom portion 225 of the body of the fuel tank 130 where liquid fuel is stored, ensures that sloshing and/or agitation of the liquid fuel during riding of the vehicle is substantially prevented. Furthermore, the above construction of the fuel tank 130 contributes to the overall reduction in the formation of fuel vapors and ensuring negligible evaporation of the fuel vapors to the atmosphere.
[00029] Many modifications and'variations of the present subject matter are possible within the spirit and scope of the present subject matter, in the light of above disclosure.