FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
A FUEL TANK WITH AN ENCLOSURE IN A TWO WHEELED VEHICLE
MAHINDRA TWO WHEELERS LIMITED,
An Indian Company, of D1 Block, Plot No. 18/2 (Part), MIDC, Chinchwad,
Pune-411 019 Maharashtra, India.
INVENTOR(S):
1. SAI SANDEEP VARLAKATI
2. SANTOSH PANDEY
3. YOGARAJA VENKATARAMAN
4. LAKSHMANAN SOLAITHEVAR
5. SATHISKUMAR SUNDARARAJU
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE INVENTION
The present invention relates to a fuel tank for storing the fuel required for propelling an internal combustion engine in a two wheeled vehicle.
BACKGROUND OF THE INVENTION
A fuel tank in a two wheeled vehicle provides for storing and supplying the fuel required for propelling the internal combustion engine. The capacity of the fuel tank is designed taking into account the fuel consumption characteristics of a two wheeled vehicle and the possible range of travel before the refilling event can occur. In a two wheeled vehicle like a motorcycle, the fuel tank is mounted in front of the saddle which is well known in the art. In the recent past attempts have been made by motorcycle manufacturers and designers alike to unveil two wheeled motorcycles with fuel tanks mounted on the rear of the saddle or beneath the saddle. The advantage that rear mounted fuel tanks offer can be seen from the need to better utilize the storage space available on front of the vehicle besides increasing the in-built fuel storage capacity of the vehicle.

One known reference in the art is disclosed through the patent publication EP 2599700 Al, where the fuel tank is mounted on a saddle-riding type vehicle in an inclined attitude in the front-to-rear direction of the vehicle. The fuelling system in this arrangement utilizes a pumping device along with necessary electrical harnesses for transferring fuel to the internal combustion engine. Use of pumping devices adds to the cost besides increasing the power requirements which indirectly leads to higher fuel consumption. Also, the increased presence of movable components has the possibility of increasing the number of modes in which the given machine can fail.
The mounting of a fuel tank beneath the saddle in a motorcycle is also known through the patent publication US 5147077 B where the space in front of the rider is utilized as a storage box for the head gear and fuel tank is arranged beneath the saddle. The known fuel tank comprises an upper half and a lower half which are seamlessly welded together to create the space for storage of the fuel. The fuel tank utilizes a set of thermistor elements to detect the reserve state of the fuel thereby indicating the refueling event to the rider. The invention described in this patent publication inherently has a drawback which is bound to surface especially when the motorcycle is moving uphill. When the motorcycle is moving uphill, the fuel stored in the front end portion of the fuel tank tends to drift rearwards and away from the fuel outlet making the internal combustion engine starve.

It is therefore, the object of the present invention to provide a fuel tank for a two wheeled vehicle on its rear end and beneath the saddle which overcomes the drawbacks of the fuel tanks for two wheeled vehicles known in the prior art.
It is another object of the present invention to provide a fuel tank for a two wheeled vehicle that is simple in construction.
It is yet another object of the present invention to provide a fuel tank for a two wheeled vehicle that is adaptive to the ground conditions on which the given vehicle traverses.
SUMMARY
A fuel tank for use in a two wheeled vehicle, according to the present invention, is provided with an enclosure.
In accordance with the present invention, there is disclosed a two wheeled vehicle having a fuel tank for storing the fuel required for propelling an internal combustion engine. The internal combustion engine can be a compressed ignition engine or spark ignition engine which converts the energy stored in the fuel into power for propelling the two wheeled vehicle. The fuel required for propelling an internal combustion engine of the two wheeled vehicle can be a liquid fuel which includes but not limited to petrol, diesel, and ethanol based bio-

fuels etc. The two wheeled vehicle is provided with a seating arrangement for the rider to conveniently sit on the vehicle in the riding condition.
The fuel tank is located underneath a seating arrangement and extends longitudinally in the fore and aft direction of the two wheeled vehicle. The enclosure provided inside the fuel tank creates the space needed for accumulating the incoming fuel from the fuel tank. The enclosure retains at least a part of the fuel accumulated inside it when the two wheeled vehicle traverses an inclined surface.
The fuel tank of the two wheeled vehicle comprises a base portion having an aperture at a pre-determined location on its bottom surface, a top portion, an enclosure located inside the base portion and a fuel outlet connected to the enclosure. The enclosure has a bottom surface provided and a plurality of side surfaces that together defines the enclosure volume. On one of the side surfaces of the enclosure there is an opening provided at a predetermined distance away from the bottom surface of the enclosure to allow the ingress of fuel from the base portion into the enclosure.
Additionally, one of the side surfaces of the enclosure having the opening is the side surface with the least height.

Further, the base portion has an aperture at a pre-determined location on its bottom surface and the enclosure also has an aperture at a predetermined location on its bottom surface. The aperture on the bottom surface of the base portion, aperture on the bottom surface of the enclosure and the fuel outlet are coaxially disposed. The fuel is transferred from the fuel tank to the fuel outlet through the enclosure. The fuel outlet typically can be a tube removably or irremovably connected to the aperture on the bottom surface of the enclosure and passing through the aperture on the bottom surface of the base portion.
As an alternative, the bottom surface of the base portion is adaptable to cooperate with the side surfaces of the enclosure thus making the bottom surface of the base portion act as the bottom surface of the enclosure. In this arrangement, the fuel outlet is connected to the bottom surface of the base portion.
The tank can be of metallic type or non - metallic type. The base portion, the top portion and the enclosure are attached to one another removably or irremovably. The base portion, the top portion and the enclosure combines to define the volume of the fuel tank. The enclosure is advantageously located on the frontal end of the base portion.
The fuel in the fuel tank is delivered to the internal combustion engine by means of gravity.

BRIEF DESCRIPTION OF THE DRAWINGS
The fuel tank in a two wheeled vehicle of the present disclosure will now be described with the help of accompanying drawings in which:
Figure 1 illustrates a side view of a two wheeled vehicle showing the outer appearance thereof in accordance with the present invention
Figure 2 illustrates a side view of the fuel tank of a two wheeled vehicle showing its general shape
Figure 3 illustrates an exploded view of the fuel tank of a two wheeled vehicle with its various elements separately indicated
Figure 4 illustrates top sectional view of the base portion and the enclosure attached therein
Figure 5 illustrates a perspective view of the enclosure
Figure 6 illustrates a front view of the enclosure showing the opening
Figure 7 illustrates the enclosure assembly
Figure 8 illustrates the level of fuel accessible to the fuel outlet in the absence of an enclosure when the vehicle is moving uphill
Figure 9 illustrates the level of fuel accessible to the fuel outlet in the presence of an enclosure when the vehicle is moving uphill
Figure 10 illustrates an alternative arrangement showing two independent fuel transfer paths

DETAILED DESCRIPTION OF THE INVENTION
Hereinafter the invention will be described in more detail with reference to one embodiment of the present invention.
A two wheeled vehicle 10 generally having a pair of wheels (Wl, W2), a manoeuvring arrangement 12, a seating arrangement 14, an internal combustion engine 16 and a fuel tank 18 is shown in figure 1. The two wheeled vehicle 10 as shown in figure 1 is a straddle type two wheeled vehicle having its engine 16 on the front and is typically a motorcycle. A pair of wheels one on the front Wl and the other on the rear W2 engage with the ground and helps in moving the two wheeled vehicle 10 forward. The manoeuvring arrangement 12 enables the rider to steer the two wheeled vehicle 10 on its given path. The seating arrangement 14 serves to provide the required seating space and comfort to the rider of the two wheeled vehicle 10. The internal combustion engine 16 provides the required propelling force to drive the two wheeled vehicle 10 forward by converting the energy stored in the fuel into useful work. The fuel to the internal combustion engine 16 is supplied from the fuel tank 18 mounted at a point relatively higher than the internal combustion engine 16.

Figures 2 in the accompanying drawings illustrate a fuel tank 18 which forms the preferred embodiment of the present disclosure. The fuel tank has two ends 17 and 19.
Now referring to figure 3, the fuel tank 18 comprises several constituents which are primarily essential for the working of the proposed invention. Fuel tank 18 comprises a base portion 22, a top portion 20, a enclosure 24 and a fuel outlet 26. The bottom surface 30 of the base portion 22 is provided with an aperture 28.
The base portion 22 of the fuel tank 18 is defined primarily by its bottom surface 30 and side wall 31 as shown in figure 4. The base portion 22 also accommodates the enclosure 24 having a bottom surface 34 and an aperture 32 provided on the bottom surface 34. As shown in figure 5 and figure 6, the enclosure 24 of the fuel tank 18 is defined by its bottom surface 34, side surfaces 36, 37, 40 & 41 and an opening 38.
Referring again to figure 1 and figure 2 of the accompanying drawings in the present disclosure, the fuel tank 18 is rigidly mounted above the rear wheel R and supported by the chassis frame (not shown in figures) of the two wheeled vehicle 10. The fuel tank 18 extends longitudinally along the length of the two wheeled vehicle 10. The seating arrangement 14 is firmly positioned above the fuel tank 18.

The ends 17 and 19 of the fuel tank 18 are separated longitudinally with one of its ends 17 disposed spatially proximate to the internal combustion engine 16 and the other end 19 disposed spatially away from the internal combustion engine 16.
The arrangement of enclosure 24 inside the fuel tank 18 will be explained in detail with reference to figure 3 and figure 4. The top portion 20, the base portion 22 and the enclosure 24 together defines the space inside the fuel tank 18 for storing the fuel. The aperture 28 on the base portion 22 of the fuel tank 18 is provided at a suitable location on the bottom surface 30 closer to the end 17 of the fuel tank 18 thereby allowing the fuel outlet 26 to pass through it. The base portion 22 serves as the lower compartment of the fuel tank 18 and houses the enclosure 24. It is advantageous to locate the enclosure 24 closer to the end 17 of the fuel tank 18. The fuel outlet 26 is removably or irremovably connected to the aperture 32 provided at a suitable location on the bottom surface 34 of the enclosure 24 which forms the enclosure assembly 35 as shown in figure 7. The fuel outlet 26 is connected to the aperture 32 either by means of fastening or welding. The enclosure assembly 35 thus formed is attached to the bottom surface 30 of the base portion 22 such that the fuel outlet 26 and the aperture 28 on the bottom surface 30 are coaxially located. The enclosure assembly 35 and the base portion 22 are fixedly or removably attached to one another either by means of welding or by using a suitable fastening means. After attaching the enclosure assembly 35 to the base portion 22, the top portion 20 is then

connected to the base portion 22 by bringing the contacting surfaces together thus forming the fuel tank 18 shown in figure 2. The contacting surfaces of the top portion 20 and the base portion 22 are joined in a manner so as to prevent any leakage of fluid from the tank 18 into the outside environment through the interstices created in between the contacting surfaces.
The enclosure 24 as shown in figure 5 and figure 6 stores the incoming fuel by virtue of the space created by the bottom surface 34 and a plurality of side surfaces 36, 37, 40 and 41. The side surfaces 40 and 41 face each other and are disposed along the direction of orientation of the fuel tank 18. The side surfaces 36 and 37 faces each other and are disposed normal to the side surfaces 40 and 41 thus forming a four walled envelope. The bottom surface 34 encloses the four walled envelope on one side thereby creating an enclosure for holding the incoming fuel. Alternatively, the bottom surface 30 of the base portion 22 can serve to enclose the four walled envelope of the enclosure 24 in which case the fuel outlet 26 is connected to the aperture 28 of the base portion 22. The surface area of the side surfaces 40 and 41 can be same or different. However, in the preferred embodiment the surface areas of side surfaces 40 and 41 are different. Also, in the preferred embodiment, the surface areas of the side surfaces 36 and 37 are the same. The height of the side surfaces 36 and 37 gradually tends to change as it progresses from one of the side surfaces 40, 41 to the other side surfaces 41, 40 correspondingly with the height being the lowest near the side surface 41 and highest near

the side surface 40 in the preferred embodiment. Another characteristic feature in the construction of the enclosure 24 is the gradual change in the width of the bottom surface 34 as it progresses from one of the side surfaces 40, 41 to the other 41, 40 correspondingly with the width being the lowest near the side surface 41 and highest near the side surface 40 in the preferred embodiment.
On at least one of the side surfaces 36, 37, 40 and 41 there is provided an opening 38 to allow the ingress of incoming fuel into the enclosure 24. In the preferred embodiment, the opening 38 is provided on the side surface 41 which is the side surface with the least height as measured from the bottom surface 34 of the enclosure 24. The opening 38 can assume any geometric shape or configuration. It is advantageous to provide an opening 38 which is U - shaped with smoothened corners. The volume of fuel present in the fuel tank 18, size of the opening 38 on the side surface 41 and its location with reference to the bottom surface 34 determines the amount of fuel that the enclosure 24 can store when the vehicle 10 usually moves on a horizontal surface.
Now the working of the invention will be explained in more detail with reference to one or more of the accompanying drawings and with special reference to figure 8 and figure 9. The various surface conditions in which the two wheeled vehicle 10 is operated is broadly classified into horizontal condition, positively inclined condition

(uphill) and negatively inclined condition (downhill). In any given surface condition, the fuel inside the fuel tank 18 enters the enclosure 24 through the opening 38 provided on the side surface 41 and then reaches the fuel outlet 26. Through the fuel outlet 26, the fuel reaches the internal combustion engine 16. The aforementioned flow path of the fuel will remain the same irrespective of the surface conditions.
For the fuel to enter the enclosure 24 through the opening 38, the fuel level inside the fuel tank 18 must have to exceed a minimum threshold level set by means of the location of the opening 38 on the side surface 41 with reference to the bottom surface 34 of the enclosure. The amount of fuel inside the fuel tank 18 that does not cross the aforementioned threshold level will not become accessible to be used for running the internal combustion engine 16. This inaccessible amount of fuel inside the fuel tank 18 is called the 'dead volume'. The use of words 'dead volume' and 'inaccessible amount' in relation to the fuel inside the fuel tank 18 must be construed as synonymous to each another. For a given volume of fuel inside the fuel tank 18 and with the location of the opening 38 of the enclosure 24 being fixed, the inaccessible amount of fuel inside the fuel tank 18 varies depending on the surface conditions upon which the two wheeled vehicle 10 moves.
Referring to figure 8, there is shown a base portion 22 and fuel outlet 26 of the fuel tank 18 with ends 17 and 19. The fuel inside the fuel

tank 18 is referenced as Fl. In the absence of enclosure 24 inside the fuel tank 18, the fuel Fl inside the tank 18 directly enters the fuel outlet 26. When the two wheeled vehicle 10 moves on a negatively inclined surface condition (downhill), for a given volume of fuel Fl inside the fuel tank 18, the fuel Fl tends to move towards the end 17 of the fuel tank there by maximizing the fuel accessible to the fuel outlet 26. When the two wheeled vehicle 10 moves on a horizontal surface condition, for a given volume of fuel Fl inside the fuel tank 18, the fuel Fl tends to remain in a state of equilibrium inside the fuel tank 18 there by keeping the fuel accessible to the fuel outlet 26 constant. When the two wheeled vehicle 10 moves on a positively inclined surface condition (uphill), for a given volume of fuel Fl inside the fuel tank 18, the fuel Fl tends to move away from the end 17 of the fuel tank 18 thereby minimizing the fuel accessible to the fuel outlet 26. While the problem of fuel inaccessibility to the fuel outlet 26 does not arise when the two wheeled vehicle 10 moves on a horizontal surface or downhill, there is a definitive problem of fuel inaccessibility in case if the two wheeled vehicle 10 moves uphill.
Referring now to figure 9, there is shown a base portion 22, enclosure 24 and fuel outlet 26 of the fuel tank 18 with ends 17 and 19. Part of the fuel stored inside the enclosure is referenced as F2 and the part of the fuel inside the fuel tank 18 will be referenced as Fl. In the presence of enclosure 24 inside the fuel tank 18, the fuel Fl inside the tank 18 enters the enclosure 24 and then moves into the fuel outlet 26 provided the level of fuel Fl inside the fuel tank 18 can cross the

minimum threshold level which is defined by the location of the opening 38 on the side surface 41. In case of the two wheeled vehicle 10 moving uphill, part of the fuel Fl inside the fuel tank 18 will tend to move away from the end 17 there by gradually depleting the amount of fuel available at the opening 38 of the enclosure 24. However, the part of the fuel F2 stored in the enclosure 24 will continue to feed the fuel outlet 26 which ensures to supply the fuel required for running the internal combustion engine 16.
An alternative embodiment is envisaged as shown in figure 10, in which there is provided a second fuel outlet 27 through which the fuel inside the fuel tank 18 is fed into the internal combustion engine 16. One end of the second fuel outlet 27 is connected to the aperture 28 provided on the bottom surface 30 of the fuel tank 18. The other end of the second fuel outlet 27 is connected to a fuel flow path (not shown) leading to the internal combustion engine 16. The second fuel outlet 27 and the fuel outlet 26 are telescopically arranged such that the apertures 28 and 32 are concentrically located. This arrangement offers ease of packaging. Alternatively, the aperture 28 can be positioned at any convenient location along the bottom surface 30 of the fuel tank 18 to which the fuel outlet 27 can be connected. Thus the arrangement described hereinbefore creates two independent fuel transfer paths from the fuel tank 18 to the fuel flow path (not shown) leading to the internal combustion engine 16. The fuel stored inside the enclosure 24 exits the fuel tank 18 through the fuel outlet 26 whose one end is connected to the aperture 32. The remaining fuel stored inside the fuel tank 18 exits through the second fuel outlet 27

whose one end is connected to the aperture 28. The arrangement as envisaged hereinbefore can significantly reduce the amount of inaccessible fuel inside the fuel tank 18 thereby maximising the fuel available for running the internal combustion engine 16.
The enclosure 24 inside the fuel tank 18 is indispensable to continuously keep feeding the fuel to the internal combustion engine 16 especially when the two wheeled vehicle 10 is moving uphill and the level of fuel inside the fuel tank 18 falls below a certain minimum threshold level.
Certain modifications and improvements in the proposed invention will become readily apparent to a person of ordinary skill in the art of fluid storage and conveyance systems and such changes must be treated as equivalents to the elements of the present invention. Changes in the claimed invention by the use of substitutes and alternatives in terms of material, method, manufacturing process, configuration, arrangement, duplication etc., will render them fall within the scope of the claimed invention.

WE CLAIM:
1. A two wheeled vehicle having a fuel tank for storing a fuel required for propelling an internal combustion engine, said fuel tank located underneath a seating arrangement and extending longitudinally in the fore and aft direction of the two wheeled vehicle characterized by an enclosure inside said fuel tank creating a space for accumulating the incoming fuel from the fuel tank and retaining at least a part of the accumulated fuel when the two wheeled vehicle traverses an inclined surface.
2. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the fuel tank comprises a base portion, a top portion and a fuel outlet such that the fuel outlet is connected to the enclosure and said enclosure is disposed inside the base portion of the fuel tank.
3. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the enclosure has a bottom surface and a plurality of side surfaces and at least one of the side surfaces of said enclosure has an opening provided at a predetermined distance away from the bottom surface of said enclosure to allow the ingress of fuel from the base portion of the fuel tank into said enclosure.

4. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the at least one of the side surfaces of the enclosure having the opening is the side surface with the least height.
5. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the base portion has an aperture at a predetermined location on its bottom surface and the enclosure has an aperture at a pre-determined location on its bottom surface such that the aperture on the bottom surface of the base portion, aperture on the bottom surface of the enclosure and the fuel outlet are coaxially disposed thereby allowing the transfer of fuel from the fuel tank to the fuel outlet through the enclosure.
6. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the bottom surface of the base portion is adaptable to cooperate with the side surfaces of the enclosure such that the fuel outlet is adaptably connected to the bottom surface of the base portion.
7. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the enclosure is located on the frontal end of the base portion of the fuel tank.
8. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the base portion, the top portion and the enclosure combines to define the volume of said fuel tank.

9. A two wheeled vehicle having a fuel tank as claimed in claim 1, characterized in that the fuel in said fuel tank is delivered to the internal combustion engine by means of gravity.
10. A two wheeled vehicle having a fuel tank substantially as herein described with reference to accompanying drawings and description.