GB2076758A

GB2076758A - Fuel Tank and Filler Pipe Therefor

Info

Publication number: GB2076758A
Application number: GB8114194A
Authority: GB
Original assignee: Ford Motor Co Ltd; Ford Motor Co
Current assignee: Ford Motor Co Ltd; Ford Motor Co
Priority date: 1980-05-09
Filing date: 1981-05-08
Publication date: 1981-12-09
Also published as: DE3017765A1; FR2484388A1; DE3017765C2; GB2076758B; FR2484388B1

Abstract

A filler pipe (1) for a fuel tank (2) comprises an outlet which terminates in a Venturi (8) positioned downstream from an internal vent pipe (4). The Venturi reduces return flow of fuel during and immediately after filling. <IMAGE>

Description

SPECIFICATION Fuel Tank and Filler Pipe Therefor The invention relates to fuel tanks and filler pipes therefor.

German Design Patent No. 73 26 179 discloses a fuel tank filler pipe which includes a funnel-shaped device disposed in the upper part of the filler pipe lying in the area of the bodywork which is so designed that when a fuel filler gun is inserted into the neck, the gun is fixed in a definite position. A vent pipe from the tank runs outside the filler pipe and communicates with the filler pipe in the vicinity of the funnel-shaped device.

This known filler pipe has the disadvantage that considerable production costs are involved in ensuring that the connections between the fuel tank and the filler pipe are securely sealed. In addition the assembly of the fuel tank in the bodywork of the motor vehicle must be carried out with a certain degree of care, so that the air vent pipe, which is separate from the filler pipe, is not unduly bent or squashed.

In an alternative construction, the air vent pipe runs inside the filler pipe. Although this construction can be made less expensively, and assembled more easily, in use, reverse flows of fuel can occur, which lead to undesirable spillages of fuel.

According so the invention there is provided a fuel tank comprising a filler pipe for discharging liquid fuel into the fuel tank having an inlet for receiving fuel, and an outlet for communicating with the tank, the outlet terminating in a Venturi.

Since the outlet of the filler pipe includes a Venturi, the flow of fuel in this area is accelerated thus avoiding a return of fuel due to the presence of a positive vapour pressure. Where the filler pipe includes an internal vent pipe, the venturi is positioned between the point at which it communicates with the tank.

The Venturi can be formed integrally with the filler pipe. On the other hand the Venturi can be formed as an extension piece attached to the lower end of the filler pipe.

The end of the extension piece may be provided with axial slots so that the extension piece grips the end of the filler pipe. The end of the plastic pipe can however also be provided with a bayonet connection by means of which it can be locked positively, onto the filler pipe.

The construction of the Venturi as an attachable extension piece allows existing fuel filler pipes to be modified.

Embodiments of the invention will now be described, by way of example only with reference to the accompanying drawings, in which: Figure 1 is a vertical partial section through a fuel tank; Figure 2 is a view of a extension piece for a fuel tank filler pipe; Figure 3 is a section through the extension piece along the line Ill-Ill in Figure 2; and Figure 4 is an alternative filler pipe extension piece.

In Figure 1 a fuel tank filler pipe 1 slopes upwardly at an oblique angle from one side of a fuel tank 2. The filler pipe 1 here comprises a filler tube 3 and a vent pipe 4 placed inside it. The lower end of the filler pipe passes via a seal 5 into the fuel tank 2 and the lower end of the vent pipe 4 is connected via a vent 6 with the vapour space in the fuel tank 2.

The lower end of the filler tube 3 carries an extension 7, indicated in dash dot lines, in which is disposed a Venturi 8. This extension is formed integrally with the filler tube 3.

In use, when fuel is pumped into the filler tube 3 from a fuel gun, the Venturi 8 causes an acceleration of the fuel-flow below the discharge 6 of the vent pipe 4 into the filler tube 3. Wavemovements are initiated in the surface of the fuel which, in cooperation with an increased atmospheric pressure in the vapour space of the fuel tank prevent any reverse flow of fuel up the filler tube 3. On completion of the filling process the wave trough indicated in dotted lines breaks down and the resulting surge of fuel attempts to flow back up the filler tube 3.

However, when the wave crest strikes the open end of the filler tube 3 the Venturi 8 acts as a restrictor. Thus even after the fuel gun is turned off a return of fuel is avoided.

Figures 2 and 3 show an alternative construction. Instead of being integrated with the filler tube 3, the Venturi 8 is formed in a separate plastic extension piece 9. The end of the extension part 9 to be attached to the lower end of the filler tube 3 has radial slots in order to allow it to flexibly clamp on to the end of the filler tube 3.

Figure 4 shows a further alternative construction in which the Venturi is formed in a separate extension piece adapted to be attached to the lower end of the filler tube 3 by a bayonet slot 11 which locks positively onto a locking bolt 1 2 indicated in Figure 1 by dotted lines in the filler tube 3. Of course a similar extension piece could be attached by sticking with a corresponding fuelresistance adhesive or by means of a latch engageable in an aperture in the filler tube 3, such as the vent 6.

Claims

1. A fuel tank comprising a filler pipe for discharging liquid fuel into the fuel tank having an inlet for receiving fuel, and an outlet for communicating with the tank, the outlet terminating in a Venturi.

2. A fuel tank according to Claim 1, wherein the Venturi is formed integrally with the filler pipe.

3. A fuel tank according to Claim 1, wherein the Venturi is formed in an extension piece mounted on the filler pipe.

4. A fuel tank according to Claim 3 wherein one end of the extension piece has axial slots which grip the end of the filler pipe.

5. A fuel tank according to Claim 3 wherein one end of the extension piece is secured to the filler pipe by a bayonet connection.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Fuel Tank and Filler Pipe Therefor The invention relates to fuel tanks and filler pipes therefor. German Design Patent No. 73 26 179 discloses a fuel tank filler pipe which includes a funnel-shaped device disposed in the upper part of the filler pipe lying in the area of the bodywork which is so designed that when a fuel filler gun is inserted into the neck, the gun is fixed in a definite position. A vent pipe from the tank runs outside the filler pipe and communicates with the filler pipe in the vicinity of the funnel-shaped device. This known filler pipe has the disadvantage that considerable production costs are involved in ensuring that the connections between the fuel tank and the filler pipe are securely sealed. In addition the assembly of the fuel tank in the bodywork of the motor vehicle must be carried out with a certain degree of care, so that the air vent pipe, which is separate from the filler pipe, is not unduly bent or squashed. In an alternative construction, the air vent pipe runs inside the filler pipe. Although this construction can be made less expensively, and assembled more easily, in use, reverse flows of fuel can occur, which lead to undesirable spillages of fuel. According so the invention there is provided a fuel tank comprising a filler pipe for discharging liquid fuel into the fuel tank having an inlet for receiving fuel, and an outlet for communicating with the tank, the outlet terminating in a Venturi. Since the outlet of the filler pipe includes a Venturi, the flow of fuel in this area is accelerated thus avoiding a return of fuel due to the presence of a positive vapour pressure. Where the filler pipe includes an internal vent pipe, the venturi is positioned between the point at which it communicates with the tank. The Venturi can be formed integrally with the filler pipe. On the other hand the Venturi can be formed as an extension piece attached to the lower end of the filler pipe. The end of the extension piece may be provided with axial slots so that the extension piece grips the end of the filler pipe. The end of the plastic pipe can however also be provided with a bayonet connection by means of which it can be locked positively, onto the filler pipe. The construction of the Venturi as an attachable extension piece allows existing fuel filler pipes to be modified. Embodiments of the invention will now be described, by way of example only with reference to the accompanying drawings, in which: Figure 1 is a vertical partial section through a fuel tank; Figure 2 is a view of a extension piece for a fuel tank filler pipe; Figure 3 is a section through the extension piece along the line Ill-Ill in Figure 2; and Figure 4 is an alternative filler pipe extension piece. In Figure 1 a fuel tank filler pipe 1 slopes upwardly at an oblique angle from one side of a fuel tank 2. The filler pipe 1 here comprises a filler tube 3 and a vent pipe 4 placed inside it. The lower end of the filler pipe passes via a seal 5 into the fuel tank 2 and the lower end of the vent pipe 4 is connected via a vent 6 with the vapour space in the fuel tank 2. The lower end of the filler tube 3 carries an extension 7, indicated in dash dot lines, in which is disposed a Venturi 8. This extension is formed integrally with the filler tube 3. In use, when fuel is pumped into the filler tube 3 from a fuel gun, the Venturi 8 causes an acceleration of the fuel-flow below the discharge 6 of the vent pipe 4 into the filler tube 3. Wavemovements are initiated in the surface of the fuel which, in cooperation with an increased atmospheric pressure in the vapour space of the fuel tank prevent any reverse flow of fuel up the filler tube 3. On completion of the filling process the wave trough indicated in dotted lines breaks down and the resulting surge of fuel attempts to flow back up the filler tube 3. However, when the wave crest strikes the open end of the filler tube 3 the Venturi 8 acts as a restrictor. Thus even after the fuel gun is turned off a return of fuel is avoided. Figures 2 and 3 show an alternative construction. Instead of being integrated with the filler tube 3, the Venturi 8 is formed in a separate plastic extension piece 9. The end of the extension part 9 to be attached to the lower end of the filler tube 3 has radial slots in order to allow it to flexibly clamp on to the end of the filler tube 3. Figure 4 shows a further alternative construction in which the Venturi is formed in a separate extension piece adapted to be attached to the lower end of the filler tube 3 by a bayonet slot 11 which locks positively onto a locking bolt 1 2 indicated in Figure 1 by dotted lines in the filler tube 3. Of course a similar extension piece could be attached by sticking with a corresponding fuelresistance adhesive or by means of a latch engageable in an aperture in the filler tube 3, such as the vent 6. Claims

6. The use of a pipe having an outlet terminating in a Venturi as a filler pipe for a fuel tank.

7. A fuel tank having a filler pipe substantially as hereinbefore described with reference to Figure 1 or Figures 2 and 3 or Figure 4 of the drawings.