WO1999042317A1

WO1999042317A1 - Fuel tank equipped with a device communicating its upper parts

Info

Publication number: WO1999042317A1
Application number: PCT/FR1999/000378
Authority: WO
Inventors: André ARNAL; Philippe Decobert; Alexis Rosseel
Original assignee: Compagnie Plastic Omnium
Priority date: 1998-02-19
Filing date: 1999-02-19
Publication date: 1999-08-26
Also published as: FR2774949A1; CA2286570A1; EP0975483A1; FR2774949B1

Abstract

The invention concerns a fuel tank with a top wall (16) and comprising a plurality of high parts (9, 10) and a conduit (15) located inside the tank for communicating between them said various high parts. The internal conduit (15) is constructed in a single piece with the tank top wall (16)

Description

Fuel tank fitted with a communication device for its upper parts

The present invention relates to a fuel tank provided with a device for communicating its upper parts.

We know that fuel tanks are equipped with ventilation valves, which, by being connected to exhaust pipes, allow the evacuation of gases generated during filling, we then speak of degassing or during driving, in which case we speaks of venting the tank, while preventing the passage of liquid fuel. To fully fulfill its role, a ventilation valve must place the high point or points of the tank in communication with the outside, it being understood that by high point, one designates a region of the tank situated under its upper wall and in which vapors of fuel accumulates, being trapped between said upper wall and the level of liquid fuel. However, in most tanks, there are a plurality of high points, which requires the provision of as many ventilation valves and exhaust ducts, under penalty of trapping a gas pocket in each unventilated high point of the tank. .

To limit the metering of evacuation conduits leaving the reservoir, it has already been proposed to connect all the valves of the reservoir to each other using a single conduit, which then acts as a manifold, and to evacuate the gases. thus collected in a single conduit connected to the collector.

However, this solution is not entirely satisfactory because it requires the presence of a number of valves as large as the number of high points of the tank and it requires the supply and installation of a relatively large number of conduits, which are relatively expensive due to the good properties of resistance to hydrocarbons and sealing which they must exhibit.

For this purpose, it is known to use multilayer pipes based on polyamide or high density polyethylene, associated with a barrier resin such as polyvinylidene fluoride or polyvinyl alcohol.

Document DE 3040160 discloses a device for placing two high points of a tank in communication.

Such a device comprises a conduit which is placed inside the tank. However, this conduit has several drawbacks.

First, it must be fixed in the upper part of the tank, which requires the supply of additional parts and the use of labor.

In addition, this conduit must be able to withstand the aggressions of the hydrocarbons contained in the tank.

The present invention aims to solve these drawbacks by proposing a new fuel tank which is simple and economical to produce.

The subject of the present invention is a fuel tank having an upper wall and comprising a plurality of high points and a duct placed inside the tank to make these different high points communicate with each other, characterized in that the internal duct is made in one piece with the upper wall of the tank.

It is advantageous, according to the invention, to produce the reservoir by bonding or welding two parts of the reservoir obtained by injection molding. In a preferred embodiment of the invention, the inner conduit is constituted by a channel made in the thickness of the upper wall of the tank.

For example, this channel can result from an additional injection of gas into the injection mold of the upper part of the reservoir, when the latter is molded. In another embodiment, the conduit is constituted by a groove formed on the internal face of the upper wall of the tank, and by a bottom which comes to weld on the edges of the groove to close it.

One of the essential advantages of the invention resides in the fact that once all the high points of the tank have been placed in communication, a single ventilation valve can be provided in any of the high points of the tank, to ensure evacuation gases trapped in the tank.

In a particular embodiment, one can provide at each end of the pipe placed inside the tank, a separating device to prevent liquid fuel from entering the pipe and only allow the passage of gases. This embodiment makes it possible to avoid possible problems of blockage of the conduit with liquid fuel accumulated in the lower part of the conduit as in a siphon. In order to better understand the invention, we will now describe an embodiment given by way of non-limiting example, with reference to the accompanying drawing in which:

FIG. 1 is an elevation view of a traditional fuel tank,

FIG. 2 is a top view of FIG. 1,

- Figure 3 is an elevational view of a fuel tank according to the invention, Figure 4 is a top view of Figure 3, Figure 5 is a sectional view along IV-IV and on a larger scale in Figure 4,

- Figure 6 is a sectional view along VI-VI in Figure 3 of the upper wall of a tank according to another embodiment of the invention.

The fuel tank 1 shown in FIGS. 1 and 2 comprises an envelope 2 whose external shape is adapted to conform to the environment of the vehicle for which the tank is intended.

As a result, the casing 2 has, on its lower face, a clearance 3 allowing the passage of the vehicle transmission bridge and, on its upper face, two lateral recesses 4 and 5 intended to make room for the vehicle components attached to the chassis. In known manner, the tank is equipped with a suction assembly, the fixing plate 6 of which appears on the upper face of the tank, a supply pipe 7 and a fuel return pipe 8 leading to said plate.

The reservoir has two high points 9 and 10 located at two of the four corners of its upper wall. Each of these high points 9 and 10 is liable to trap a pocket of gas.

The tank is provided, in each of its high points, with a valve 11, 12 whose function is to allow the evacuation of the gases and to prevent the passage of the liquid fuel. The two valves are interconnected by a manifold 13 to which a discharge pipe 14 is connected.

We see that the manifold 13 travels on the upper wall of the tank in avoiding the recesses 4 and 5 and the fixing plate 6, which forces it to follow a long and winding course.

In the embodiment of Figures 3 and 4, the parts of the tank identical to those which have just been described bear the same reference numbers. The collector is replaced by an inner conduit 15 which connects the two high points 9 and 10 of the tank.

As can be seen in FIG. 4, this internal duct 15 extends from a high point 9 to the other 10 without undergoing a change of direction other than that imposed by the reliefs of the reservoir. In other words, the conduit 15 remains here in a vertical plane.

Other configurations could, depending on the shape of the tank, be preferable.

The reservoir is produced in two parts 2a, 2b which are joined by gluing or welding along a median plane 17, each part resulting from an injection molding or from an implementation of the extrusion / compression process.

Independently of the high point communication channel, the tank includes a ventilation valve 18 and a discharge pipe 19, in one of the two high points.

As seen in Figure 5, the inner conduit 15 is formed in the thickness of the upper wall 16 of the tank.

To this end, the upper part 2a of the reservoir is injection molded and an amount of inert gas such as nitrogen which is injected into the mold cavity corresponding to said conduit and to the core of the molten plastic material. has repelled the plastic and has formed a channel, as is known, the ends of this channel being opened by machining after molding.

As a result, the inner duct is an integral part of the tank, which avoids having to supply a duct and to mount it inside the tank.

In the embodiment of FIG. 6, the internal conduit 15 ′ is produced in the form of a U-section groove 20 formed on the internal face of the upper wall 16 ′.

The groove 20 is closed on its longitudinal opening directed towards the inside of the tank by a plate 21 of identical or compatible plastic material. that constituting the upper wall 16 ′ of the reservoir.

This plate 21 constitutes a bottom which closes the groove and forms with it the internal duct 15 '.

It is understood that the embodiment which has just been described has no limiting character and that it can receive any desirable modifications without departing from the scope of the invention.

Claims

1 - Fuel tank having an upper wall (16,16 ') and comprising a plurality of high points (9,10) and a duct (15,15') placed inside the tank to communicate these different between them high points, characterized in that the inner conduit (15,15 ') is made in one piece with the upper wall (16,16') of the tank.

2 - Fuel tank according to claim 1, characterized in that the inner conduit (15) is constituted by a channel formed in the thickness of the upper wall (16) of the tank.

3 - Fuel tank according to claim 2, characterized in that the channel results from an additional injection of gas into the injection mold of the upper part of the tank, when the latter is molded.

4 - Fuel tank according to claim 1, characterized in that the inner conduit (15 ') is constituted by a groove (20) formed on the inner face of the upper wall (16') and by a bottom (21) which is welded on the edges of the groove to close it.

5 - Fuel tank according to any one of claims 1 to 4, characterized in that it comprises, at each end of the pipe placed in the tank, a separating device to prevent liquid fuel from entering the pipe and does not allow the passage of gases.

6 - Fuel tank according to any one of the preceding claims, characterized in that it is produced by bonding or welding of two parts (2a, 2b; 2'a) of the tank obtained by injection molding.