FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10, rule 13)
TITLE OF THE INVENTION
A Capsule Fuel storage Tank for vehicle and method of
manufacturing thereof
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Sachin Lale
Manasi Mone
Mahesh Shinde
Indian nationals of
TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed.

Field of invention:
The present invention relates to a fuel storage system and more particularly this invention relates to a capsule fuel storage tank for vehicle and method of manufacturing thereof.
Background of the Invention:
Automobile Industry is undergoing a revolutionary turn with the new product developments for various applications, features, designs and customer expectations. Automobiles can be classified based on the vehicle applications and customer segments viz. Passenger and Commercial / Personal and Contract.
Day by day reliability is becoming the key parameter for designing of components, aggregates and systems to meet the desired product life, which in turn is dictated by customer usage profile and load patterns. In view of this, design of many components turns out to be a challenge; fuel tank being one such component.
A conventional (fossil) fuel tank used for commercial vehicles usually has a cylindrical shape or a rectangular box section with rounded edges. Though the conventional fuel tank provides advantages like ease of manufacturing and simple construction, there are a few disadvantages offsetting the advantages as mentioned above. The conventional fuel tank has more dead or unusable fuel volume. The conventional fuel tank also has low structural durability under slosh and vibration condition leading to failure of fuel tank. In order to reduce the slosh effect, there are more number of baffles required to be provided in a said conventional fuel tank system which in turn lead to low structural durability. Yet, in conventional design the end plates of the tank are most susceptible to the sloshing effects of fuel. The seam wefded joint of the end plates becomes the weakest location and most of the structural and slosh failures are observed here. These failures are in the form of leakage from the seam joint. Also, in the conventional fuel tank structure, the dead volume of the fuel is more. The dead volume of fuel is the quantity of fuel remaining below the level of the suction

point of suction module, rendered unusable. This is because the fuel below the suction point is spread over the entire length of the tank.
The present invention is conceptualised and developed taking into consideration these drawbacks. The present invention gives an opportunity to overcome these disadvantages by virtue of its shape and construction.
Objects of invention:
The main object of the present invention is to provide a capsule fuel storage tank for vehicle and method of manufacturing thereof.
Another object of the present invention is to provide a capsule fuel storage tank which reduces the "slosh" load at the end in partially filled tank and to eliminate the leakages at the end of said tank.
Yet another object of the present invention is to provide a capsule fuel storage tank
which facilitates an opportunity to save cost due to requirement of less number of
baffles.
Yet another object of the present invention is to provide a capsule fuel storage tank
which helps to reduce the dead volume of fuel in the tank thus aiding utilisation of
maximum tank capacity.
Still another object of the present invention is to provide a capsule fuel storage tank
which prevents dislocation of mounting straps during usages by virtue of tank
construction itself.
Statement of Invention:
A capsule fuel storage tank for vehicle comprises; a cylindrical shell (1) constituting a middle portion; a first spherical cup (2a) and second spherical cup (2b) fitted on end of said cylindrical shell (1) respectively; at least two baffles (3a and 3b) fitted at the joinery of said cylindrical shell(1) and said first and second spherical cups (2a and 2b) respectively; said cylindrical shell (1) having a filler neck assembly (4) for filling fuel in

said tank, an assembly fuel suction and level sensor unit flange (5), a fuel return pipe (6), a drain plug (7); a metal straps (8a and 8b) provided for mounting said fuel tank; a mounting brackets (9a and 9b) provided on chassis for mounting said fuel tank.
The fuel tank, in accordance with this invention, wherein said cylindrical shell (1) comprises a joggled ends (13) formed at both edges during rolling operation before seam welding of said cylindrical shell (1).
The fuel tank, in accordance with this invention, wherein said first (2a) and second spherical cups (2b) comprises a depressions (11a) and (11b) respectively at the end portion for providing necessary stiffness to the said fuel tank.
The fuel tank, in accordance with this invention, wherein said baffles (3a and 3b) are formed out of sheet metal and disposed at both joggle ends (13) of said cylindrical shell (1) respectively.
The fuel tank, in accordance with this invention, wherein said baffle (3a and 3b) comprises plurality of holes punched in them to reduce the slosh force of the fuel and to maintain a uniform fuel level throughout the tank.
The fuel tank, in accordance with this invention, wherein said baffles (3a and 3b) are spot welded (14) to both the joggle ends (13) of the said cylindrical shell (1) and provides reinforcement for mounting fuel tank.
The fuel tank , in accordance with this invention, wherein said first spherical cup (2a) and second spherical cup (2b) joined at the both joggle ends (13) of said cylindrical shell (1) respectively by using joggle joint followed by CO2 welding (12) of said joggled joint to provide stiffness to the tank.
The fuel tank , in accordance with this invention, wherein said filler neck assembly (4), assembly fuel suction and level sensor unit flange (5), fuel return pipe (6), drain plug

(7) are welded onto said cylindrical shell (1) of tank using Metal Inert Gas (MIG) brazing process.
The fuel tank, in accordance with this invention, wherein said mounting straps (8a and 8b) are disposed on the joggled ends (13) of said cylindrical shell (1) for preventing the dislocation of said straps (8a and 8b) during usages and the entire assembly of the capsule fuel tank is fitted onto the brackets (9a and 9b) with the help of said mounting straps (8a and 8b).
A method of manufacturing said capsule fuel storage tank comprising the steps of;
• Blanking of sheet metal of required size followed by blanking of holes of required diameter is done for the filler neck (4), fuel return pipe (6), assembly fuel suction and level sensor unit (5) and drain plug (7);
• Rolling the sheet metal into a cylinder and forming a joggled ends during said rolling operation;
• Joining the edges of rolled sheet metal with the help of seam welding to form the cylindrical shell (1);
• Joining the baffles (3a) and (3b) at both edges of said cylindrical shell (1) with the help of spot welding;
• Joining the deep drawn first spherical cup (2a) and second spherical cup. (2b) at the both edge of the cylindrical shell (1) by using the joggle joint followed by CO2 welding of said joggled joint between the first spherical cup (2a) and second spherical cup (2b) and the middle shell (1);
• Joining other parts or sub assemblies like filler neck assembly (4), assembly fuel suction and level sensor unit flange (5), fuel return pipe (6), drain plug (7) are welded onto the tank using MIG brazing process;
• Providing the entire assembly of the capsule fuel tank onto the brackets
(9a and 9b) with the help of mounting straps (8a and 8b).
Brief Description of Invention:

A capsule fuel storage tank for vehicle comprises; a cylindrical shell (1) constituting a middle portion; a first spherical cup (2a) and second spherical cup (2b) fitted on end of said cylindrical shell (1) respectively; at least two baffles (3a and 3b) fitted at the joinery of said cylindrical shell(1) and said first and second spherical cups (2a and 2b) respectively; said cylindrical shell (1) having a filler neck assembly (4) for filling fuel in said tank, an assembly fuel suction and level sensor unit flange (5), a fuel return pipe (6), a drain plug (7); a metal straps (8a and 8b) provided for mounting said fuel tank; a mounting brackets (9a and 9b) provided on chassis for mounting said fuel tank.
Detailed description of Invention:
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same.
Figure-1a shows front view of capsule fuel tank in accordance with the present invention.
Figure-1b shows the side view of capsule fuel tank in accordance with the present invention.
Figure-2 shows the front view of capsule fuel tank with mounting arrangement fitted on vehicles in accordance with this invention..
Figure-2a shows the sectional view of the joggle joint along with strap and baffle in accordance with this invention.
Figure-3 shows the exploded view of the capsule fuel tank in accordance with this invention.
Now referring to figures-01 to 03, A capsule fuel storage tank for vehicle comprises; a cylindrical shell (1) constituting a middle portion; a first spherical cup (2a) and second spherical cup (2b) fitted on end of said cylindrical shell (1) respectively; at least two baffles (3a and 3b) fitted at the joinery of said cylindrical shell(1) and said first and second spherical cups (2a and 2b) respectively; said cylindrical shell (1) having a filler

neck assembly (4) for filling fuel in said tank, an assembly fuel suction and level sensor unit flange (5), a fuel return pipe (6), a drain plug (7); a metal straps (8a and 8b) provided for mounting said fuel tank; a mounting brackets (9a and 9b) provided on chassis for mounting said fuel tank.
The composite shape of the tank is achieved by rolling the sheet metal into a cylinder and the joint is seam welded to form the cylindrical shell (1) of the tank. The said seam joint of the cylindrical shell (1) is placed near the top half of the tank to prevent or minimise the possibility of any leakage.
Both the edges of said cylindrical shell (1) comprises a joggled ends (13) formed before seam welding of said cylindrical shell (1) during rolling operation.
The first spherical cup (2a) and second spherical cup (2b) are manufactured by using deep drawing manufacturing process. The said first (2a) and second spherical cups (2b) comprises depressions (11a) and (11b) respectively at the end portion provided during drawing process thus providing necessary stiffness to the said cups (2a and 2b) and hence to said fuel tank. The said baffles (3a and 3b) are formed out of sheet metal and disposed at the joinery of edges of said cylindrical shell (1) and said first (2a) and second spherical cup (2b). The said baffle (3a and 3b) comprises plurality of holes punched in them to reduce the slosh force of the fuel and to maintain a uniform fuel level throughout the tank.
Before rolling the cylindrical shell (1), which is middle shell, into the cylindrical shape, blanking of holes of required diameter is done for the filler neck (4) for filling fuel in tank, fuel return pipe (6), assembly fuel suction and level sensor unit (5) and drain plug (7). After seam welding of the cylindrical shell (1), the said baffles (3a and 3b) are spot welded (14) to both the joggle ends (13) of the said cylindrical shell (1). This is followed by CO2 welding (12) of the joggled joint between the spherical cups (2a and 2b) and the cylindrical shell (1). The CO2 welded joggle joint is a stronger joint as compared to a seam welded joint thereby making the capsule fuel tank leak proof. The said joggle joint also provides stiffness to the tank.

Subsequently, other parts / sub assemblies like a filler neck assembly (4), assembly fuel suction and level sensor unit flange (5), fuel return pipe (6), drain plug (7) are welded onto the tank using MIG brazing process. The entire assembly of the capsule fuel tank is then fitted onto the brackets (9a and 9b) with the help of mounting straps (8a and 8b) which is disposed on the joggled ends (13) of said cylindrical shell (1) thereby preventing the dislocation of said straps (8a and 8b) during usages. The brackets (9a and 9b) are bolted on the chassis (10) of vehicle.
In accordance with the present invention, method of manufacturing a capsule fuel tank comprising the steps of;
• Blanking of sheet metal of required size followed by blanking of holes of required diameter is done for the filler neck (4), fuel return pipe (6), assembly fuel suction and level sensor unit (5) and drain plug (7);
• Rolling the sheet metal into a cylinder and forming a joggled ends during said rolling operation;
• Joining the edges of rolled sheet metal with the help of seam welding to form the cylindrical shell (1);
• Joining the baffles (3a) and (3b) at both edges of said cylindrical shell (1) with the help of spot welding;
• Joining the deep drawn first spherical cup (2a) and second spherical cup (2b) at the both edge of the cylindrical shell (1) by using the joggle joint followed by CO2 welding of said joggled joint between the first spherical cup (2a) and second spherical cup (2b) and the middle shell (1);
• Joining other parts or sub assemblies like filler neck assembly (4), assembly fuel suction and level sensor unit flange (5), fuel return pipe (6), drain plug (7) are welded onto the tank using MIG brazing process;
• Providing the entire assembly of the capsule fuel tank onto the brackets
(9a and 9b) with the help of mounting straps (8a and 8b).
The present invention reduces the "slosh" load at the end in partially filled tank and to eliminate the leakages at the end of said tank. It also facilitates an opportunity to save

cost due to requirement of less number of baffles.The present invention helps to reduce the dead volume of fuel in the tank thus aiding utilisation of maximum tank capacity and the tanks has joggle ends on which the said mounting straps are disposed which prevents dislocation of mounting straps during usages.
The present structure of Capsule fuel tank basically comprises of a cylindrical shell (1) which is the middle portion of fuel tank and the first spherical cup (2a) and second spherical cup (2b) are forming as end portions of fuel tank.
The said baffles (3a and 3b) are seam welded to the edge of said cylindrical shell (1). Other accessories like fuel filler neck (4), fuel return pipe (6), tank unit flange (5) and drain plug (7) are welded externally onto the said cylindrical shell (1).
The fuel tank assembly is mounted onto the longitudinal member of the vehicle chassis (10) with the help of mounting straps (8a and 8b) located on the joggle ends (13) on the cylindrical shell (1) of fuel tank. The mounting straps (8a and 8b) are made up of metal. The joggle joints help to locate the mounting straps (8a and 8b) and retain them in place. The baffles (3a and 3b) act as reinforcement for the mounting of fuel tank.
During vehicle motion, the fuel keeps sloshing inside the tank. The sloshing is worst when the tank is partially filled. The said baffles (3a and 3b) are used to dampen the sloshing of fuel inside the capsule fuel tank.
The first spherical cup (2a) and second spherical cup (2b) are end portions of capsule fuel tank. The first spherical cup (2a) and second spherical cup (2b) dampen the sloshing movement of the fuel in addition to the baffles (3a and 3b) and the actual load on the end portions which are first spherical cup (2a) and second spherical cup (2b) is reduced considerably and issue of leakage is eliminated unlike the seam weld joint at the end plate of conventional fuel tank structure. The reduced sloshing also reduces the failures of fuel level sender unit.

The shape of first spherical cup (2a) and second spherical cup (2b) itself functions as a baffle and also improves the overall structural and slosh strength of the capsule fuel tank. Thus the less baffles are required and hence reduce the cost of manufacturing of capsule fuel tank. Since capsule fuel tank shape reduces the sloshing inside the tank which in turn reduces the load on the mounting brackets. The capsule fuel tank having an aerodynamic shape which minimises the wind loading (and/or air eddy currents) during vehicle in motion, thus reducing the further load on the mounting brackets. The shape of the capsule fuel tank has a better performance under vacuum as well as pressure.
Also, the fuel below the suction point remains only in the cylindrical shell (1) which is middle portion of fuel tank. The said first spherical cup (2a) and second spherical cup (2b) portions allows the residual fuel to accumulate mostly in the cylindrical shell (1) or middle body of the tank when the fuel level goes on reducing and thus reducing the dead volume of fuel. The present invention of capsule fuel tank can be used to . continue with the conventional mounting scheme of the vehicle.
The foregoing description is a specific illustrative embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.

We Claim:
1.A capsule fuel tank structure comprises; a cylindrical shell (1) constituting a middle portion; a first spherical cup (2a) and second spherical cup (2b) fitted on end of said cylindrical shell (1) respectively; at least two baffles (3a and 3b) fitted at the joinery of said cylindrical shell(1) and said first and second spherical cups (2a and 2b) respectively; said cylindrical shell (1) having a filler neck assembly (4) for filling fuel in said tank, an assembly fuel suction and level sensor unit flange (5), a fuel return pipe (6), a drain plug (7); a metal straps (8a and 8b) provided for mounting said fuel tank; a mounting brackets (9a and 9b) provided on chassis (10) for mounting said fuel tank.
2. The fuel tank as claimed in claim 1, wherein said cylindrical shell (1) comprises a joggled ends (13) formed at both edges during rolling operation before seam welding of said cylindrical shell (1).
3. The fuel tank as claimed in claim 1, wherein said first (2a) and second spherical cups (2b) comprises a depressions (11a) and (11b) respectively at the end portion for providing necessary stiffness to the said fuel tank.
4. The fuel tank as claimed in claim 1, wherein said baffles (3a and 3b) are formed out of sheet metal and disposed at both joggle ends (13) of said cylindrical shell (1) respectively.
5. The fuel tank as claimed in claim 1, wherein said baffle (3a and 3b) comprises plurality of holes punched in them to reduce the slosh force of the fuel and to maintain a uniform fuel level throughout the tank.
6. The fuel tank as claimed in claim 1, wherein said baffles (3a and 3b) are spot welded (14) to both the joggle ends (13) of the said cylindrical shell (1) and provides reinforcement for mounting fuel tank.

7. The fuel tank as claimed in claim 1, wherein said first spherical cup (2a) and second spherical cup (2b) joined at the both joggle ends (13) of said cylindrical shell (1) respectively by using joggle joint followed by CO2 welding (12) of said joggled joint to provide stiffness to the tank.
8. The fuel tank as claimed in claim 1, wherein said filler neck assembly (4), assembly fuel suction and level sensor unit flange (5), fuel return pipe (6), drain plug (7) are welded onto said cylindrical shell (1) of tank using MIG brazing process.
9. The fuel tank as claimed in claim 1, wherein said mounting straps (8a and 8b) are disposed on the joggled ends (13) of said cylindrical shell (1) for preventing the dislocation of said straps (8a and 8b) during usages and the entire assembly of the capsule fuel tank is fitted onto the brackets (9a and 9b) with the help of said mounting straps (8a and 8b).
10. A method of manufacturing a capsule fuel tank comprising the steps of;
• Blanking of sheet metal of required size followed by blanking of holes of required diameter is done for the filler neck (4), fuel return pipe (6), assembly fuel suction and level sensor unit (5) and drain plug (7);
• Rolling the sheet metal into a cylinder and forming a joggled ends during said rolling operation;
• Joining the edges of rolled sheet metal with the help of seam welding to form the cylindrical shell (1);
• Joining the baffles (3a) and (3b) at both edges of said cylindrical shell (1) with the help of spot welding;
• Joining the deep drawn first spherical cup (2a) and second spherical cup (2b) at the both edge of the cylindrical shell (1) by using the joggle joint followed by CO2 welding of said joggled joint between the first spherical cup (2a) and second spherical cup (2b) and the middle shell (1);

• Joining other parts or sub assemblies like filler neck assembly (4),
assembly fuel suction and level sensor unit flange (5), fuel return pipe
(6), drain plug (7) are welded onto the tank using MIG brazing process;
• Providing the entire assembly of the capsule fuel tank onto the brackets
(9a and 9b) with the help of mounting straps (8a and 8b).