Fuel tank for a vehicle

Field of the Invention:

The present invention relates to "Fuel tank for a vehicle "and more particularly relates to fuel tank construction used on three wheelers.

Background of the Invention:

A fuel tank for a automobile is required to be light and strong, to be leak proof and easily produced. Normally any automobile running on gasoline will have a fuel tank for gasoline, wherein the volume for the tank is specified only with respect to the maximum amount of gasoline that the tank shall be capable of carrying.

Generally the fuel tanks in two wheelers form a style part and are made of steel or polymer resin with low permeability. In case of three wheelers it is typically hidden within the body of three wheelers located either in the front of the vehicle near the driver seat or in the rear portion below the passenger's seat. The said fuel tank used in three wheelers is normally made of polymer resin with a regular shape of square or rectangle with all the corners rounded off.

In the above mentioned construction for fuel tank, the said fuel tank faces the problem of leakage through the vent provided on the tank due to vapour build up within the tank. The vent on the fuel tank acts as a breather for the fuel tank. Due to exposure to high ambient temperature either for the environment or for location of tank within the engine compartment, there is vapour build up within the tank. This vapour build up inside the fuel tank subsequently reduces the volume available within the tank for gasoline to occupy whereby the vapour pressure acts on the gasoline to ooze it out through the available breather vent, as can be explained as per Pascal's law.

In the light of the aforesaid circumstances it is an object of the present invention to prevent fuel loss through breather provided in the fuel tank.

Summary of the Invention:

The present invention has been devised in view of the above problems and it is therefore an object of the present invention is to prevent fuel loss from the fuel tank.

Another object of the present invention is to provide a large fuel tank without widening the width of the fuel tank.

A further object of the present invention is to introduce an additional volume inside the fuel tank.

Yet another object of the present invention is to provide space for vapours without much change in the shape of the tank.

Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Detailed Description of the Invention:

It is further to be noted that the present invention is not limited to the described embodiment and many other changes and modifications may be made without departing from the scope of the appended claims.

A preferred embodiment of a fuel tank unit of an automobile according to the present invention will be described hereunder. The present invention is applied to a three wheeler or like vehicles.

Referring to figure 1, a three wheeler passenger carrier is provided with a relatively small wheel diameter with that of motorcycles. A single wheel (101) in the front is placed ahead of a metallic cowl (102) which is located in the centre of the front view of the vehicle. The said three wheeler is controlled by a handle bar (103) placed behind the said front cowl (102). The front cowl (102) is further extended upwards and is provided with a large opening to fit a transparent glass (104) for driver's visibility. A floor board (105) is formed with a height just above the centre of the wheel but below the top surface of the wheel (101). The said floor board (105) extends from the bottom most portion of the front cowl (102) to rear end of the passenger seat cabin support structure. A partition wall or B pillar (106) is provided perpendicular to floor board (105), located in the mid way portion between passenger seat structure (107) and front cowl (102). The height of the partition wall (106) is nearly equal to the height of driver's seat (108) top surface. A driver seat
(108) is provided between the said partition wall (106) and the front cowl (102) for the driver wherein the rear end of the seat nearer to partition wall (106). The passenger seat mounting structure attaches with extended body structure or cabin (109) of the three-wheeler to cover the remaining two wheels (110) on top and partially on sides and extends beyond rear end of the wheel substantially. The said extended body structure (109) is almost a cube extended longitudinally with bottom portion completely open. The extended structure or cabin (109) is a inverted 'U' shaped metallic sheet structure with open end of the inverted 'U' is joined with a step like structure joining two side walls to form a longitudinally extended cube. The sidewalls of the cabin (109) are provided with inverted 'U' shaped recess (111) to allow rear wheels (110) to swing according to the movement of the wheel at the bottom most position of the cabin (109). The rear side of the cabin (109) is provided with an opening to fit a door or lid. The passenger seat (107) is on the passenger seat support structure. A gap is formed between the passenger seat (107) and the partition wall or B pillar (106) to form a region to accommodate and support the passengers and luggage. A sheet (112) extends from the rear end of the vehicle to the top most end of the front cowl (102) to cover the vehicle at the top supported by tubular support structure.

The said sheet (112) is generally a soft top made preferably of a resin material.

The rear end portion of the floor board is attached with 'U' shaped brackets spaced apart within the overall width of the vehicle. A pair of link arms is pivotably attached to the brackets through independent bolts. The rear end of the link arm is provided with a mounting bracket to fit a shock absorber bottom end. The rear end of the link is attached with a cylindrical member parallel to the axis of the pivot bolt to fit bearings and oil seal on both link arms. The axis of the cylinder member nearly co-incides with the axis of the 'U' shaped recess provided on the side wall. A wheel axle passes through the bearings fitted on the cylindrical member attached to link member (arm). Outer end of the axle is attached with a circular flange provided with bolts press fitted in a circular pitch equidistantly. A wheel is fitted on the flange fastened by nuts (the fitment of wheel is same on both left and right side). The inner end of the axle is attached with a coupling member.

The front cowl, the partition wall and the floorboard attached to a ladder shaped frame place below the floorboard.

On one side of the crankshaft, a magneto is mounted to generate electric current to charge the battery, provide electric spark at the spark plug to ignite the fuel air mixture in the combustion chamber, to operate the horn, wiper, lights etc. An additional wheel is provided and attached to the frame at the left inner side of the compartment. The electrical system for spark generation, charging the battery, lighting the bulbs and activating wipers and horn is provided on the step like passenger support structure at the inner side and inside the engine compartment.

Typically the fuel tankincludes a main body portion preferably of rectangular shape integrally coupled with a goose neck portion to fill fuel into the fuel tank. The goose neck portion extends diagonally upward away from the main body portion. The goose neck portion is provided with a breather vent on it. Generally another breather vent is placed on the upper flat surface of fuel tank. The second breather vent is at a lower height with respect to the first breather vent which is provided on the goose neck portion. A liquid disturbance wave is generated within the fuel tank when liquid such as for example fuel or gasoline moves from the front to the rear or vice versa inside fuel tank. The sloshing of fuel within the fuel tank leads to leakage of fuel through the second breather vent located on flat upper surface of the fuel tank. Since the fuel tank top or upper surface is uniform flat surface, it is contemplated that fuel is filled up to that level. There is a tendency of vapour formation for any hydrocarbon fuels when exposed to open atmosphere. So whenever vapours build up, these vapours are formed on the upper surface of the fuel tank, exerting pressure on the fuel and thereby leading to leakage through breather vent located on the upper surface of the fuel tank.

According to one of the preferred embodiment of the present invention and referring to figure 2, a hump like structure 201 is integrally configured and positioned on the upper surface 206 of the fuel tank 202 thereby increasing the volume of the fuel tank 202. The fuel tank body is rectangular in shape is provided with a goose neck 203. Further on the goose neck a breather vent 204 is provided. The previously placed breather vent 205 on the upper flat surface 206 is shifted on to the top of the hump structure 201. Whenever there is a vapour generation, all vapours get trapped within the hump structure 201 since fuel level is automatically maintained till the bottom edge of the hump 206.

The said measures described above prevent the fuel to ooze out from the tank breather vent due to pressure build up.

The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the claims.

We Claim:

1. A fuel tank for three wheeler comprising:

a rectangular shaped fuel tank body;

a first breather on the goose neck portion of the fuel tank

a hump shaped portion integrally configured on the upper surface of the fuel tank; and

a second breather is provided on the top of the hump shaped portion.