GB2233636A

GB2233636A - Vent system for fuel tank

Info

Publication number: GB2233636A
Application number: GB9015459A
Authority: GB
Inventors: Palu Attilio Dal
Original assignee: Fabbrica Italiana Serrature Torino FIST SpA
Current assignee: Fabbrica Italiana Serrature Torino FIST SpA
Priority date: 1989-07-14
Filing date: 1990-07-13
Publication date: 1991-01-16
Also published as: IT1232552B; FR2649651A1; FR2649651B1; GB9015459D0; DE4021998A1; IT8967590A0

Abstract

A vent system for an auxiliary recirculating pipe (9, 12) of an automotive fuel tank comprises a chamber (11) located in the auxiliary pipe (9, 12) and having a larger section than the pipe. Preferably the chamber (11) is formed by a plastics container having offset inlet and outlet portions connected to the auxiliary pipe, and has a portion (18) complementary in shape to a main fuel pipe (1). The system is intended to prevent backflow of fuel.

Description

VENT SYSTEM FOR THE AUXILIARY RECIRCULATING PIPE OF AN AUTOMOTIVE FUEL

TANK The present invention relates to a vent system for the auxiliary recirculating pipe located between an automotive fuel tank and the main fuel supply pipe, in the vicinity of the union.

Said auxiliary recirculating pipe provides for removing any air inside the tank when this is filled via the main fuel supply pipe. As the auxiliary pipe may also be filled with fuel. at least up to a certain level, when the air in the tank is removed, the fuel inside the auxiliary pipe is forced upwards to where the auxiliary pipe is connected to the main pipe. This, at least temporarily. results in relatively high counterpressures in the two pipes in turn resulting in backflow and leakage of the fuel towards the union and possible arrest of the fuel filler gun.

The aim of the present invention is to provide a vent system for the auxiliary recirculating pipe of an automotive fuel tank designed to overcome the above drawbacks, i.e. which provides for effective venting with no backflow of fuel to the union.

With this aim in view, according to the present invention, there is provided a vent system for the auxiliary recirculating pipe of an automotive fuel tank, characterised by the fact that it comprises means located in said auxiliary pipe and defining a chamber having a larger section than the same.

A non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Fig.1 shows a front view of portions of the main and auxiliary pipes supplying fuel to an automotive tank and featuring the vent system according to the present invention; Fig.2 shows a side view perpendicular to that of Fig.1; Fig.s 3, 4 and 5 show respective sections along lines MIIII W-W and V-V in Fig.2.

Number 1 in Fig.s 1 and 2 indicates a main pipe (without the top portion) for supplying fuel from a union to an automotive fuel tank. Said pipe 1 is of known type, and may conveniently be formed from plastic material with undulated bellows type portions 2 for facilitating assembly to the vehicle. Pipe 1 presents an end portion 3 molded in one piece with an annular portion 4 (Fig.5) which is fitted in fluidtight manner to the inlet pipe 5 of a tank 6 (indicated partially by the dot-and-dash line).

Substantially parallel to main pipe 1, there is provided a known auxiliary recirculating pipe 8, conveniently formed from plastic material,, undulated in the form of a bellows. and smaller in section than main pipe 1. Auxiliary pipe 8 presents a bottom portion 9 located between tank 6 (in known manner not shown) and a container 11 forming part of the vent system according to the present invention; and a top portion 12 located (in known manner not shown) between container 11 and the top portion of main pipe 1,, close to the connection to the union.

As shown partially in Fig.2, the top portions of main pipe 1 and auxiliary pipe 8 fit through respective holes 13 in a bracketed body 14 (secured to the vehicle frame in known manner not shown) for positioning pipes 1 and 8 as required.

Portion 12 of auxiliary pipe 8 and container 11 (Fig.2) are connected by means of an annular portion 15. which is molded in one piece with an end portion of portion 12 and fitted in fluidtight manner (by means of an outer clamp 16) on to outlet pipe portion 17 of container 11. Portion 9 of auxiliary pipe 8 and inlet pipe portion 171 of container 11 are connected in the same way.

Container 11 is in the form of a closed chamber, considerably larger in section than auxiliary pipe 8, and of such a height as to define a capacity of a few tenths of a litre.

Container 11 is curved so as to form a cavity 18 in which to house main pipe 1, and presents a downward-facing cup-shaped main body 19 of upwardly decreasing section. and a flat wall 20 closing off the bottom.

outlet and inlet portions 17 and 171 are offset and extend integrally from the top portion of main body 19 and flat wall 20 respectively.

The two parts 19 and 20 of container 11 are conveniently molded from plastic material and connected, e.g. hot-blade welded. along the common edge 22.

Connection of container 11 to main pipe 1 is shown in Fig.s 1 and 5. At the bottom of cavity 18, which presents a slightly larger radius than main pipe 1, container 11 presents an integral C-section portion 24 defining an inner channel 25 and projecting inwards of cavity 18 so as to adapt to the radius of main pipe 1.

Said portion 24 presents two vertical outer appendixes 27 housed in a cavity 28 in main pipe 1, and inner channel 25 houses a clamp 29 which is tightened about pipe 1 so as to secure container 11 angularly and axially to the same.

Said position is conveniently established so that flat wall 20 of container 11 is substantially on a level with the top wall of fuel tank 6.

Using the vent system according to the present invention, when tank 6 is filled with fuel via main pipe 1. fuel is allowed to enter substantially only the bottom portion 9 of auxiliary pipe 8 located between tank 6 and container 11. Moreover, container 11, which presents a considerably larger section than auxiliary pipe 8, provides for accommodating the fuel inside its chamber. with substantially no backflow into top portion 12 of auxiliary pipe 8. thus preventing fuel leakage from the union and reducing the counterpressure in main pipe 1.

The advantages of the vent system according tc> the present invention will be clear from the foregoing description. Moreover. container 11 may also act as a holding tank for increasing the ma imum. capacity of tank 6.

To those skilled in the art it will be clear that changes may be made to the embodiment described and illustrated herein without, however, departing from the scope of the present invention. For example, container 11 may be designed differently, or formed from blow-molded plastic. etc.

Claims

1) - A vent system for the auxiliary recirculating pipe (8) of an automotive fuel tank (6), characterised by the fact that it comprises means (11) located in said auxiliary pipe (8) and defining a chamber having a larger section than the same.

2) - A system as claimed in Claim 1. characterised by the fact that said chamber (11) presents a capacity of a few tenths of a litre.

3) - A system as claimed in Claim 1 or 2, characterised by the fact that said means comprise a container (11) having inlet (171) and outlet (17) portions connected to respective portions (9, 12) of said auxiliary pipe (8).

4) - A system as claimed in Claim 3. characterised by the fact that said inlet (171) and outlet (17) portions are offset.

5) - A system as claimed in claim 3 or 4, characterised by the fact that said container (11) is formed from plastic material.

6) - A system as claimed in one of the foregoing Claims from 3 to 5. characterised by the fact that said container (11) presents means (24. 29) for connection to a main pipe (1) supplying fuel to said tank (6).

7) - A system as claimed in one of the foregoing Claims from 3 to 6. characterised by the fact that said container (11) presents a portion (18) complementary in shape to a main pipe (1) supplying fuel to said tank 1 If (6).

8) A system as claimed in one of the foregoing Claims from 3 to 7. characterised by the fact that said container (11) presents a flat bottom wall (20).

9) - A system as claimed in Claim 8, characterised by the fact that said container (11) is inserted between said portions (9, 12) of said auxiliary pipe (8) in such a position that said bottom wall (20) is substantially on a level with the top wall of said tank (6).

10) - A container (11) designed to form part of a vent system for the auxiliary recirculating pipe (8) of an automotive fuel tank (6), as claimed in one of the foregoing Claims.

11) - A vent system for the auxiliary recirculating pipe of an automotive fuel tank, and relative container designed to form part of said system. substantially as described and illustrated with reference to the accompanying drawings.

Published 1991 at The Patent Office. State House. 66171 lliali Holborn. London WC 1 R 4T11- Further ropies niai. be obtained froni The Patent Otti(t. Sale, Branch. St Marv Cray. Orpinglon. Kent 13MS 3RD- Printed bv Mulliplex tec.iiilique hd- St Man- Cr.ty. Kent. Con. 1 /87