FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)


TITLE OF THE INVENTION
CNG cylinder packaging in boot space
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
Mr. Santosh B Sonawane, Mr. Kiran G Rawal
both 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 automobile and more particularly this relates to CNG
tank .packaging in boot space area.
BACKGROUND OF INVENTION
In the automobile field, the use of compressed natural gas (CNG) as an alternative fuel is principally due to ecological reasons. CNG is made by compressing natural gas (which is mainly composed of methane [CH4]), to less than 1% of its volume at standard atmospheric pressure.
Compressed natural gas vehicles require a greater amount of space for fuel storage than conventional gasoline power vehicles. Since it is a compressed gas, rather than a liquid like gasoline, CNG takes up more space for each gasoline gallon equivalent (GGE). It is stored and distributed in hard containers, at a normal pressure of 200-220 bar (2900-3200 psi), usually in cylindrical or spherical shapes.
Conventional method of mounting cylindrical CNG tank in the vehicle is in the boot space area. CNG tank is mounted on well designed channel type structure called frame, which is directly bolted on the floor at four positions. Mounting of this frame on floor results into transfer of all load to the floor. As there is no any structural member underneath of the vehicle at that particular four mounting positions, crack starts at the critical section of the floor & then it propagates because of vehicle dynamic loading, which finally causes floor cracks at several positions. This is the major drawback of above stated design for CNG tank mounting in boot space area.
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This floor cracks failure can be avoided by providing all mounting points inside structural member of the vehicle which shall be designed for load of CNG tank mounting assembly. Therefore all load of CNG tank mounting frame will transfer from floor to that structural member & floor crack can be avoided. Also tubular design for frame would be better for high strength design & avoid structural failures.
OBJECT OF INVENTION
• The main object of this invention is to provide CNG tank mounting arrangement for automobile with effective utilization of boot space as well as well ease of spare wheel removal.
• Another object of this invention is to provide CNG tank mounting arrangement for automobile which is able to provide an additional stiffness to BIW.
• Yet another object of this invention is to provide CNG tank mounting arrangement for automobile which is able to have good accessibility along with easy to mount/demount.
• Yet another object of this invention is to provide CNG tank mounting arrangement for automobile which is able to effectively distribute the load to floor as well as to mounting means.
• Yet another object of this invention is to provide CNG tank mounting arrangement for automobile which is having good NVH characteristics.
• Yet another object of this invention is to provide CNG tank mounting arrangement for automobile which is simple in construction and cost effective.
SUMMARY OF THE INVENTION
CNG tank mounting arrangement in accordance with this invention consists of cradle which is made by welding of six different shaped tubes of high strength material to each other. Four short length tubes of same size are welded to two long tubes for structural support.
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Base plate is welded at each end of the long tubes, Base plate is also made up of high strength steel material to withstand against high loading. Slots are provided on base plates as well as on the floor for bolting arrangement. This cradle is to be fitted on top of the floor. Under the floor there are underbody brackets, which are to be arc welded inside long member. Long member is the structural member of the vehicle. So bolts can be fitted through base plates, floor and underbody brackets. This is how CNG tank mounting load is distributed from floor to underbody brackets and long members.
Accordingly, the present invention discloses a mounting structure for mounting a CNG tank in the boot of a vehicle comprising: a plurality of tubes assembled together to form a cradle-like structure to be fitted on top of boot floor, said plurality of tubes comprising at least one front cradle tube, at least one rear cradle tube and a plurality of reinforcement tubes; a plurality of fastening means for fastening said CNG tank onto said cradle-like structure; a front mounting arrangement comprising a front base plate and a front underbody bracket member assembled with said front cradle tube, such that the CNG tank mounting load is effectively and uniformly and effectively distributed from said boot floor to said front underbody bracket member; and a rear mounting arrangement comprising a rear base plate and a rear underbody bracket member assembled with said rear cradle tube, such that the CNG tank mounting load is effectively and uniformly distributed from said boot floor to said rear underbody bracket member.
Further, the front underbody bracket member is fixed below the boot floor such that said front base plate. The boot floor and said front underbody bracket member are fastened together with a vehicle long member to effectively distribute the CNG tank mounting load. The rear underbody bracket member is fixed below the boot floor such that said rear base plate. The boot floor and said rear underbody bracket member are
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fastened together with a vehicle long member to effectively distribute the CNG tank mounting load.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 shows CNG tank mounting arrangement provided in boot space of the vehicle in
accordance with this invention.
Fig.2 shows top view of CNG tank mounting arrangement
Fig.3 shows the sectional view of front mounting arrangement
Fig.4 shows the sectional view of rear mounting arrangement
Fig 5 shows the assembly of top strap
Fig 6 shows the assembly of bottom strap
DETAILED DESCRIPTION OF INVENTION
Referring to the Fig 1 & 2, CNG tank (1) mounting arrangement consists of a cradle. Cradle is made by six tubes, out of which two bend tubes (5) & two cross tubes (4) are welded to front and rear cradle tubes (9 & 10) as shown in the figure. Bend tubes (5) & cross tubes (4) are used for providing structural support and reinforcement to the front and rear cradle tubes. CNG tank (1) is mounted on cradle tubes (9 & 10) having two rubber blocks (6) on it at both the sides. Rubber blocks (6) are provided at equidistance on cradle tubes (9 & 10) for avoiding metal to metal contact between tank (1) & cradle tubes (9 & 10). The tank (1) is fitted on cradle by means of four straps (3) & fasteners, keeping necessary clearances from suspension towers & rear seat of the vehicle. CNG tank (1) is having a tank valve (2) at it's RH side. Height of cradle is optimized for ease of spare wheel removal from boot space as well as rigidity.
Fig 3 shows, front mounting arrangement consists of front base plate (7) & front underbody bracket (12). Front base plate (7) is welded at the end of front cradle tube (9)
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where flaring is provided on base plate for getting high welding strength. Also base plate is having one sided flanging for better strength. There are two slots given on plate for bolting arrangement. Respective front underbody bracket (12) is welded inside long member (22) having two slots with weld nut. There is a front reinforcement (13) provided on the rear floor (11) below base plate (7) for additional strength.
Fig 4 shows rear mounting arrangement consists of rear base plate (8) & rear underbody brackets (14). Rear base plate (8) is welded at the end of rear cradle tube (10) where flaring is provided on base plate for getting high welding strength. Also rear base plate (8) is having one sided flanging for better strength. There is only one slot given on plate for bolting arrangement. Respective rear underbody bracket (14) is welded inside long member (22) having one slot with weld nut. Same as front side, there is also a rear reinforcement (15) provided on the rear floor (11) below rear base plate (8) for additional strength.
Fig 5 shows the assembly of top strap consists of metal strap top (16) having hook (18) & stud (17) welded at the ends. Then hook (18) is welded to front cradle tube (9) and stud (17) will fit to another bottom strap at other side of cradle by means of nut. Rubber strap is provided in between metal strap top (16) & tank (1) for avoiding direct contact.
Fig 6 shows the assembly of bottom strap consists of metal strap bottom (19) having a bracket (20) welded at one side to provide mounting means between straps. This is achieved by providing one slot on that bracket. Reinforcement strap (21) is welded on metal strap bottom (19) for more strength.
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WE CLAIM
1. A mounting structure for mounting a CNG tank in the boot of a vehicle
comprising:
a plurality of tubes assembled together to form a cradle-like structure to be fitted on top of boot floor, said plurality of tubes comprising at least one front cradle tube, at least one rear cradle tube and a plurality of reinforcement tubes;
a plurality of fastening means for fastening said CNG tank onto said cradle-like structure;
a front mounting arrangement comprising a front base plate and a front underbody bracket member assembled with said front cradle tube, such that the CNG tank mounting load is effectively and uniformly and effectively distributed from said boot floor to said front underbody bracket member; and
a rear mounting arrangement comprising a rear base plate and a rear underbody bracket member assembled with said rear cradle tube, such that the CNG tank mounting load is effectively and uniformly distributed from said boot floor to said rear underbody bracket member.
2. The mounting structure as claimed in claim 1, wherein said front underbody bracket member is fixed below the boot floor such that said front base plate, said boot floor and said front underbody bracket member are fastened together with a vehicle long member to effectively distribute the CNG tank mounting load.
3. The mounting structure as claimed in claim 1, wherein said rear underbody bracket member is fixed below the boot floor such that said rear base plate, said boot floor and said rear underbody bracket member are fastened together with a vehicle long member to effectively distribute the CNG tank mounting load.
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4. The mounting structure as claimed in claim 1, wherein rubber blocks are provided at equidistance on front and rear cradle tubes for avoiding metal to metal contact between said cradle tubes and said CNG tank mounted thereon.
5. The mounting structure as claimed in claim 1, wherein said fastening means for fastening said CNG tank onto said cradle-like structure include straps and fasteners.
6. The mounting structure as claimed in claim 1, wherein flaring is provided on said front base plate and said front base plate is fixed at the end of said front cradle tube.
7. The mounting structure as claimed in claim 6, wherein said front base plate has
a one sided flanging for increased strength.
8. The mounting structure as claimed in claim 2, wherein two slots are provided on said front base plate for fastening arrangement.
9. The mounting structure as claimed in claim 2, wherein said front underbody bracket is preferably welded inside said long member.
10. The mounting structure as claimed in claim 2, wherein a front reinforcement is provided on the boot floor below said front base plate for additional strength.
11. The mounting structure as claimed in claim 1, wherein flaring is provided on said rear base plate and said rear base plate is fixed at the end of said rear cradle tube.
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12. The mounting structure as claimed in claim 11, wherein said rear base plate has a one sided flanging for increased strength.
13. The mounting structure as claimed in claim 3, wherein one slot is provided on said rear base plate for fastening arrangement.
14. The mounting structure as claimed in claim 3, wherein said rear underbody bracket is preferably welded inside said long member.
15. The mounting structure as claimed in claim 3, wherein a rear reinforcement is provided on the boot floor below said rear base plate for additional strength.
16. The mounting structure as claimed in claim 1 and 5, wherein said fastening means includes a top strap and a bottom strap, said top strap consists of a metal strap top having a hook member and a stud connected at its end, said hook is connected to said front cradle tube and said stud is fitted to said bottom strap,
17. The mounting structure as claimed in claim 16, wherein rubber strap is provided in between said metal strap top and CNG tank to avoid direct metal-to-metal contact.
18. The mounting structure as claimed in claim 16, wherein said bottom strap consists of a metal strap bottom having a bracket connected at one side.
19. The mounting structure as claimed in claim 16, wherein reinforcement strap is provided on said metal strap bottom for increased strength.
20. The mounting structure as claimed in claim 1, wherein the height of said cradle¬like structure is optimized for ease of spare wheel removal from boot floor.
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21. A mounting structure for mounting a CNG tank in the boot of a vehicle substantially as hereinabove described with reference to the accompanying drawings.