FORM 2
THE PATENT ACT 1970 (as amended)
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE: "JET PUMP ARRANGEMENT FOR A FUEL TANK"
Name and address of the Applicant:
TATA MOTORS LIMITED, an Indian company having its registered office at
Bombay house, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra,
INDIA.
Nationality: INDIAN
The following specification particularly describes the invention the manner in which it is to be performed.

FIELD OF INVENTION
This invention pertains to Jet pump arrangement in metallic fuel tank and especially to means for maintaining a sufficient fuel level to pump inlet during vehicle operation and cooling down the temperature of hot return fuel line in a smaller height metallic fuel tank.
BACKGROUND OF THE INVENTION
In the recent years, there is increasing trend of common rail diesel vehicles that demands fuel system wherein typically a requirement of high flow rate and cooling down the temperature of hot return fuel line. High flow rate demands a very good aspiration rate (filling rate) in surge pot to keep the fuel available all time to the pump. Conventional intank fuel pump supply unit mounted on fuel tank has an integrated plastic surge pot called as fuel module with jet pump to maintain the fuel level in the reservoir and cooling down the temperature of return fuel from the engine. But in case of smaller height fuel tank, where it is not possible to have integrated plastic surge pot (reservoir) and jet pump to fuel pump unit due to variable constraints and hence requires a separate metallic reservoir welded to automotive metallic fuel tank at bottom. Welded metallic reservoir stores the fuel and makes fuel available to Intank pump suction tip locally. But in absence of jet pump, it leads to poor filling rate in reservoir i.e. insufficient fuel level to pump inlet inside the reservoir in case of low fuel level and various vehicle operation, such as cornering, braking, acceleration and slope climbing and downhill at low fuel level causes sometime fuel unavailable at the suction tip of pump. Further it leads to high temperature issue in the fuel tank due to high return fuel temperature in Common rail engine vehicle.
SUMMARY OF THE INVENTION
This invention relates to arrangement made in metallic reservoir to have jet pump and umbrella valve to overcome the problem of poor filling rate and high temperature issues in fuel tank due to hot return fuel.
In this invention, for a smaller height metallic fuel tank, where there is no provision of integrated plastic surge pot (reservoir) and jet pump to fuel pump, the fuel jet pump is incorporated in a metallic reservoir mounted on bottom shell of metallic fuel tank. A jet pump arrangement made in small plastic elbow stem fits into the pocket created and arrangement made in one side of the metallic reservoir for maintaining the fuel level to provide the a continuous fuel to the fuel pump when fuel level in tank is low and further to

cool down the temperature of hot return fuel with mixing of cold fuel of fuel tank. The jet pump has a Venturi orifice made in metal inserted into plastic part which directs the flow of fuel upward into a Venturi passage which has a converging section, parallel section and then finally diverging section made in metallic reservoir. This continuously draws fuel from fuel tank to keep the reservoir always full and over flows during vehicle operation. An arrangement made in other side of metallic reservoir for umbrella valve to be inserted for the fuel to come inside the metallic reservoir during first fill from fuel tank. Once the fuel enters the metallic reservoir, the umbrella valves prevent the fuel to go back to tank.
Therefore an objective of this invention is to provide a reservoir welded to bottom of the metallic fuel tank continuously filled during vehicle operation of cornering, braking, acceleration and slope climbing at low fuel, which maintains the level of fuel in metallic reservoir to provide a continuous supply to fuel pump.
Another objective on this invention is hot fuel handling. It cool down the temperature of hot return fuel from common rail engine by mixing with cold fuel of tank outside the metallic reservoir through jet pump operation fitted into the metallic reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig.Ol is exploded view of the invention in showing different parts assembly in to metallic reservoir.
Fig.02 is front view of invention in section showing fuel flow through the plastic elbow stem to metallic reservoir.
Fig.03 is sectional view of pocket in metallic reservoir for elbow stem arrangement.
Fig.04 is top view of invention showing parts arrangement in metallic reservoir.
Fig.05 is sectional view of pocket in metallic reservoir for umbrella valve arrangement
DETAILED DESCRIPTION OF THE PREFEREED EMBODIMENT
The current design for smaller height fuel tank has fuel pump without integrated reservoir and jet pump mounted on the fuel tank, where fuel return port directly opens to small separate reservoir. This reservoir may be a metallic reservoir. Hence, there is no mechanism to fill the reservoir and to cool down the hot return fuel temperature. Small opening and

baffle arrangement is provided on the metallic reservoir to maintain same fuel level both inside and outside.
As shown in Fig 1 and Fig 2, a fuel supply arrangement 100 includes a fuel pump 23 without integrated surge pot is assembled on a tank assembly 1 (also referred to as fuel tank 1), where fuel is drawn through the strainer resting on a metallic reservoir 16 (also referred to as "reservoir 16") and return hot fuel is coming back to tank passing through the small plastic part called an elbow stem with jet 11 and finally reaching to the metallic reservoir 16. Due to venturi-effect of a metallic jet 14 orifice, it sucks the surrounding fuel of the fuel tank 1 and keeps the metallic reservoir 16 always full and reduces the return line fuel temperature by mixing cold fuel of tank with hot fuel of return line 7. At least one protrusion, such as a protrusion 17 and a protrusion 21 (also refereed to as a second protrusion 21) are made in the bottom surface of the metallic reservoir 16 to position an elbow stem 11 and an umbrella valve 22 respectively. The protrusions 17 and 21 fluidly communicate with the fuel tank 1. The elbow stem 11 is mounted on the reservoir 16 from the bottom and it is accommodated in a space between the reservoir 16 and the tank 1 created by the protrusion 17.
The return line 7 of the fuel pump 23 inside the tank assembly 1 is having a female connector 8 at their end that fits to a male stem 9 of the elbow stem with jet 11. The elbow stem 11 is a plastic part having a male stem 9 at one end to suit a joint for the female connector 8 coming from the return line 7 of the fuel pump 23 and at other end one small metallic insert 14 having small orifice diameter pressed fit to create venturi effect for better aspiration rate and cooling of the hot fuel. In addition to this one small plastic cap 13 is pressed fit at same end to divert the fuel path upward. A small projection 12 is made in between these two ends of elbow stem 11 that fits into a depression 20 made in the reservoir 16. The small protrusion fluidly communicates with the tank assembly 1. This elbow stem 11 has two resting legs on the bottom surface that almost touches to bottom tank shell 2 after the fitment of reservoir 16 to the bottom shell 2. So it keeps the elbow stem 11 position stable with respect to the metallic reservoir 16 and the bottom shell 2.
The small pocket or protrusion 17 is made in one corner of the metallic reservoir 16, where it is having two different heights (Fig 2 & Fig 3) so that there should not be any direct impact of fuel waves on the metallic jet orifice 14 due to sloshing effect in the tank assembly 1. This pocket has got two plunging holes 18,19 for fixing the elbow stem 11 and the tube 15 for the

jet pump opening respectively. In one of the plunging hole 18 the elbow stem with jet 11 is inserted in such a way that O-ring 10 seals the passage between the metallic reservoir 16 and tank assembly 1. Small projection 12 given in the elbow stem 11 also pressed fit into the small depression 20 given in metallic reservoir 16. This small projection 12 ensures that alignment of elbow stem 11 with respect to the metallic reservoir 16 is correct and having proper orientation and opening of jet orifice 14 into the passage of other plunging hole 19.
A cylindrical tube 15 is welded to the metallic reservoir 16 on the opening of plunging hole 19. This cylindrical tube 15 is having straight portion and diverging section at the opening end to the metallic reservoir 16. The fuel comes out of the cylindrical tube 15 and fills the reservoir 16. The aspiration rate is maintained to keep the reservoir 16 always full and overflowing.
The small rectangle pocket 21 or protrusion 21 is made in the metallic reservoir 16 to have an arrangement for conventional umbrella valve 22 which is required to fill the metallic reservoir 16 during first time filling to fuel tank 1. Valve 22 fits on the small circular hole 24 (Fig 4) made in flat surface of pocket 21 in the reservoir 16. It seals the passage from metallic reservoir 16 to fuel tank 1. It also operates whenever fuel level in the metallic reservoir 16 goes below the tank 1 fuel level. Here again depression (Fig 5) is made at two different heights so that there should not be any direct impact of fuel waves on umbrella valve 22 opening due to sloshing effect in the tank.
The metallic reservoir 16 with all arrangement of elbow stem with jet 11 and the umbrella valve 22 is then spot welded to the bottom shell 2 of the fuel tank 1. Resting legs of the elbow stem 11 almost touches to bottom surface of the tank 1 (Fig 2). So in this scenario there is no chance of dislocation of the elbow stem 11 from the metallic reservoir 16. Finally, seam welding is done between top and bottom shell of metallic tank 1. During the intank-pump 23 fitment to the fuel tank, first the return line end connector 8 gets snap fit to elbow male stem 9 and then intank pump flange 3 is assembled on tank opening.
Advantages
a) A jet pump arrangement constructed in smaller height metallic fuel tank.
b) A metallic reservoir constructed with pocket to accommodate elbow stem with jet to have Venturi effect in order to meet the requirement of sufficient fuel level to pump inlet in case of low fuel level and various vehicle operation, such as cornering,

braking, acceleration and slope climbing and to further to cool down the temperature of hot return fuel from the engine, c) A metallic reservoir constructed with another pocket to accommodate an umbrella valve, wherein it is required to fill the metallic reservoir during first time filling to fuel tank and whenever fuel level in the metallic reservoir goes below the tank fuel level.
Referral Numerals:

Reference Number Description
100 Fuel supply arrangement
1 Tank assembly, Fuel tank
2 bottom tank shell
3 Pump flange
7 Hot fuel return line
8 Female connector
9 Male stem
10 O-ring
11 Elbow stem
12 Small projection
13 Small plastic cap
14 Metallic jet
15 Tube
16 Metallic reservoir
17 Protrusion
18 Plunging hole
19 Plunging hole
20 Depression
21 Protrusion, second protrusion
22 Umbrella valve
23 Fuel pump
The foregoing description is a specific 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 fuel supply arrangement for a fuel tank, said fuel supply arrangement comprising, a reservoir mounted on a bottom surface of said fuel tank, a fuel pump removably integrated with said reservoir, said fuel pump having
a strainer for drawing fuel from said reservoir and a return line for returning fuel to
said reservoir through an elbow steam, characterized in that, at least one protrusion provided on a bottom surface of said reservoir and
fluidly communicating with said fuel tank, said elbow stem being mounted on said
bottom surface of said reservoir, and is accommodated in a space between said
reservoir and said fuel tank created by said protrusion.
2. The fuel supply arrangement as claimed in claim 1, wherein said protrusion includes two plunging holes opening to said fuel tank and said elbow stem being mounted on a first plunging hole.
3. The fuel supply arrangement as claimed in claim 2 further comprising a cylindrical tube, said cylindrical tube having a straight portion mounted on a second plunging hole and a diverging section at said opening end to said reservoir.
4. The fuel supply arrangement as claimed in any one of the preceding claims further comprising a metallic jet orifice provided on said elbow stem, said metallic jet orifice oriented inline with said second plunging hole and being configured to suck fuel of said fuel tank and keep said reservoir full.
5. The fuel supply arrangement as claimed in any one of the preceding claims, wherein said metallic jet orifice being configured to reduce said return line fuel temperature by mixing said fuel of said fuel tank with said hot fuel of said return lines.
6. The fuel supply arrangement as claimed in any one of the preceding claims, wherein a plastic cap is pressed fit to said elbow stem, to divert said fuel path upward.

7. The fuel supply arrangement as claimed in any one of the preceding claims, wherein said return line includes a female connector at an end that fits to a male stem of said elbow stem.
8. The fuel supply arrangement as claimed in claim 1, wherein said protrusions include a second protrusion and an umbrella valve is mounted on said second protrusion.
9. The fuel supply arrangement as claimed in claim any one of the preceding claims, wherein said reservoir is a metallic reservoir.