GB2423513A

GB2423513A - Fuel filler pipe

Info

Publication number: GB2423513A
Application number: GB0504000A
Authority: GB
Inventors: Rob Kavanagh
Original assignee: Nissan Motor Manufacturing UK Ltd; Nissan Technical Centre Europe Ltd
Current assignee: Nissan Motor Manufacturing UK Ltd
Priority date: 2005-02-26
Filing date: 2005-02-26
Publication date: 2006-08-30
Anticipated expiration: 2025-02-26
Also published as: EP1855904B1; GB0504000D0; EP1855904A1; WO2006090117A1; DE602006010823D1; GB2423513B

Abstract

A fuel filler pipe for an automobile, the pipe having a main body and a filler neck, wherein the main body has an inward deformation (130, 134) at a pre-selected axial position in the pipe, the deformation being arranged so as to position a fuel gun nozzle inserted into the pipe for reducing disruption to the laminar flow of fuel from the nozzle through the pipe. The deformation can be used to prevent insertion of an incorrect fuel, for example a diesel fuel gun nozzle, but allow insertion of a correct fuel, for example an unleaded fuel gun nozzle.

Description

Title: Fuel Filler Pipe The present invention relates to a fuel filler

pipe for automobiles.

Conventional fuel filler pipes are manufactured with an insert which serves several purposes. Firstly, for petrol driven automobiles the insert is designed to prevent a user inserting a diesel fuel gun nozzle into the filler pipe of the petrol driven vehicle, thus preventing the user from inadvertently contaminating the vehicle fuel tank with the wrong fuel. The insert restricts entry of the diesel fuel gun nozzle.

A second purpose of the insert is to position the nozzle of the fuel gun relative to the longitudinal axis of the fuel filler pipe to reduce disruption to the laminar flow of the fuel from the nozzle along the filler pipe. This is beneficial in that where there is a poor laminar flow of fuel the back pressure can sometimes cause the fuel gun control to trip and cut off the supply of fuel, and in extreme cases can actually cause a reverse flow of fuel out of the filler pipe which is in itself extremely dangerous. However, the provision of the insert significantly increases the time and cost of manufacture of the filler pipe.

The present invention seeks to provide an improved fuel filler pipe.

In accordance with a first aspect of the invention there is provided a fuel filler pipe for an automobile, the pipe having a main body and a filler neck, wherein the main body has an inward deformation at a preselected axial position in the pipe, the deformation being arranged so as to position a fuel gun nozzle inserted in to the pipe for reducing disruption to the laminar flow of fuel from the nozzle through the pipe.

In accordance with a second aspect of the inspection there is provided a fuel filler pipe for a petrol drive automobile, the pipe having a main body and a filler neck, wherein the main body has an inward deformation at a preselected axial position in the pipe arranged to prevent insertion of a diesel fuel gun nozzle beyond said position and allow insertion of an unleaded fuel gun nozzle beyond said position.

Advantageously, the inward deformation is formed by at least one inwardly projecting portion of a sidewall of the main body of the pipe.

In one embodiment the inwardly projecting portion of said sidewall extends the full circumference of the main body.

In a preferred embodiment of the invention the inward deformation is formed by three angularly spaced inwardly projecting portions of said sidewall of the main body.

Advantageously, the three inwardly projecting portions of said sidewall of the main body are equi-angularly spaced about said sidewall..

In a further prefered embodiment of the invention the or each of said inwardly projecting portions is generally frusto-conical in shape and has a radially inner surface having an arcuate cross-section in a plane perpendicular to the longitudinal axis of the main body of the pipe at said position.

Advantageously, the or at least one of said inwardly projecting portions has a radially inner surface having a substantially part cylindrical shape coaxial with said pipe main body.

The present invention is further described hereinafter, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a longitudinal section through a conventional fuel filler pipe; Figure 2 is a view of the pipe of Figure 1 in the direction of arrow A. Figure 3 is a longitudinal section through a preferred embodiment of a fuel filler pipe according to the present invention; Figure 4 is a view of the pipe of Figure 3 in the direction of arrow A; and Figure 5 is a section along the line V-V of Figure 3 showing the shape of the deformations in the pipe of Figure 3.

Referring firstly to Figures 1 and 2, these show a conventional automobile fuel filler pipe 10. The filler pipe has a main body 12 connecting a filler neck 14 with a fuel tank (not shown). The fuel filler pipe 10 is used for fuel supply to the fuel tank of the automobile and the main body 12 forms a conduit from the filler neck 14 to the fuel tank.

The filler pipe illustrated in Figures 1 and 2 has a filler neck 14 at an outer end of the filler pipe, and a main body 12 which is provided with an insert 16.

As can be seen in the drawings the insert 16 is generally funnel-shaped, being circular in cross-section with a part or frusto-conical neck connecting the inlet portion of the insert with a narrow, circular outlet 18 at the downstream end, the diameter of which is sufficient to allow passage of the nozzle of fuel gun Because the diameter of the outlet 18 provides a relatively close fit for the fuel gun nozzle it is offset from the longitudinal axis of the insert 16 and breather holes 20 are provided in the part conical neck of the insert 16.

The insert 16 is a press-fit or welded or otherwise secured to the inner surface of the filler pipe main body 12.

The insert 16 serves two main purposes. Firstly, as the nozzle of the fuel gun is inserted through the filler neck 14 and into the main body 12 of the pipe it is guided through the outlet 18 which positions the nozzle relative to the pipe 12 to provide a smoother laminar flow of the fuel from the nozzle through the pipe 12.

The position of the fuel gun nozzle relative to the pipe 12 determines the smoothness of the laminar flow of fuel. If it is positioned such that this flow is disrupted, the consequent build up in pressure in the pipe 12 can cause a back flow of fuel out of the inlet 14 which can be extremely dangerous. If less severe, it can cause the fuel flow to shut off intermittently.

The outlet 18 of the insert 16 is therefore arranged to position the fuel gun nozzle to reduce or eliminate this potential hazard.

Secondly, the insert can be used in fuel filler pipes for petrol driven automobiles to prevent a user inserting a diesel fuel gun nozzle into the filler pipe of the petrol driven vehicle. In this case, the outlet 18 is of a diameter which is sufficient to allow passage of the nozzle of an unleaded fuel gun but is too narrow to allow the passage of the nozzle of a diesel fuel gun.

Referring now to Figures 3 and 4, these show views, similar to those of Figures 1 and 2, of a preferred form of fuel filler pipe 100 according to the present invention.

As can be seen from the drawings, the filler pipe is generally conventional in design and construction. However, instead of an insert such as the insert 16 used in the conventional filler pipe, the main body 112 of the pipe is deformed inwardly to provide a restriction which serves the same purpose as the insert of the conventional pipe. In the illustrated embodiment the restriction or inward deformation is formed by three inwardly projecting portions or deformations 120, 122 and 124 of the sidewall of the pipe main body, although it will be appreciated that this number may be varied. For example, the restriction may be form by an inward deformation of the pipe extending the full circumference (360 LI) of the pipe main body 112.

However, the use of three inwardly projecting portions or deformations (sometimes referred to as lozenges) as shown in Figures 3 to 5 is the preferred form since they can define a "circular" restriction, equivalent to the outlet 18 of the conventional insert, to receive the fuel gun nozzle.

As can be seen from Figures 4 and 5, one or more of the three deformations is typically of a generally frusto-conical shape having a side wall or walls extending from the inner surface of the main body of the fuel pipe 100 and terminating in a radially inner surface 130, 132, 134. The or each surface 130, 132, 134 is conveniently of arcuate shape in cross-section taken in a plane perpendicular to the longitudinal axis of the pipe 100 at that point. Although where the projecting portions or deformations are shallow, as are deformations from 20, 21, 22 in Figure 5, the actual shape of the surfaces 132, 134 is not critical.

Where the inner surfaces 130, 132, 134 extend only a few millimetres axially of the pipe they can have a generally rounded surface in the axial direction. Where a surface extends for more than a few millimetres it is preferable for the surface to be generally part cylindrical in shape.

The portions 120, 122, 124 and the inner surfaces 130, 132, 134 can be shaped to provide an orifice which narrows longitudinally of the pipe 100 in a direction away from the filler neck 114 to facilitate location of the fuel gun nozzle.

Where the surfaces 130, 132, 134 are part cylindrical in shape this is preferably coaxial with the pipe 100 and may conveniently be tapered inwardly in the direction away from the filler neck. The effect is to define a "cylindrical" or "circular" aperture which is dimensioned to allow passage of the nozzle of an unleaded fuel gun whilst preventing passage of the nozzle of a diesel fuel gun.

Whilst the number and shape of the protrusions shown in Figure 3 and 4 and described above is to be preferred, it will be appreciated that any suitable number and shapes may be used.

The preferred form of fuel filler pipe as described above provides a significant saving in both time and cost in the manufacture of such filler pipes.

Claims

Claims 1 A fuel filler pipe for an automobile, the pipe having a main body

and a filler neck, wherein the main body has an inward deformation at a preselected axial position in the pipe, the deformation being arranged so as to position a fuel gun nozzle inserted into the pipe for reducing disruption to the laminar flow of fuel from the nozzle through the pipe.
2 A fuel filler pipe for a petrol driven automobile, the pipe having a main body and a filler neck, wherein the main body has an inward deformation at a preselected axial position in the pipe arranged to prevent insertion of a diesel fuel gun nozzle beyond said position and allow insertion of an unleaded fuel gun nozzle beyond said position.
3 A fuel filler pipe as claimed in claim 1 or 2 wherein the inward deformation is formed by at least one inwardly projecting portion of a sidewall of the main body.
4 A fuel filler pipe as claimed in claim 3 wherein said inwardly projecting portion of said sidewall extends the full circumference of the main body.
A fuel filler pipe as claimed in claim 3 wherein the inward deformation is formed by three angularly spaced inwardly projecting portions of said sidewall of the main body.
6 A fuel filler pipe as claimed in claim 5 wherein the three inwardly projecting portions of said sidewall of the main body are equi-angularly spaced about said sidewall..
7 A fuel filler pipe as claimed in any of claims 3 to 6 wherein the or each of said inwardly projecting portions is generally frusto-conical in shape.
8 A fuel filler pipe as claimed in any of claims 3 to 7 wherein the or at least one of said inwardly projecting portions has a radially inner surface having an arcuate cross-section in a plane perpendicular to the longitudinal axis of the main body of the pipe at said position.
9 A fuel filler pipe as claimed in any of claims 3 to 8 wherein the or at least one of said inwardly projecting portions has a radially inner surface having a substantially part cylindrical shape coaxial with said pipe main body.

A fuel filler pipe constructed and arranged substantially as described herein with reference to Figures 3 to 5.