GB2376460A

GB2376460A - Fuel filler cap

Info

Publication number: GB2376460A
Application number: GB0114601A
Authority: GB
Inventors: Anthony Alan Fitzgerald; David Thomas Bowles
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2001-06-15
Filing date: 2001-06-15
Publication date: 2002-12-18
Also published as: GB0114601D0

Abstract

In a fuel filler cap comprising a body 110 114 having an aperture through it, a pressure relief valve 115 to control the flow of air trough the aperture, and a cover 112 extending over one end of the aperture, projections 142, 144, 146, 148 are provided on the body and the cover which co-operate to define a labyrinthine path between the atmosphere and the valve, so that any dirt carried by indrawn air is trapped before entering the fuel tank. As shown the projections are tubular and extend substantially parallel with the aperture 114. The valve 115 comprises elements which permit entry or exit of air to compensate for under or over pressure within the fuel tank.

Description

A Fuel Filler Cap

The present invention relates to fuel filler caps for motor vehicles.

A typical known fuel filler cap is shown in Figure 1. It comprises a filler cap body 10 and a cover 12. The body 10 is generally cylindrical with an open ended central bore 14 through it, an outwardly extending flange 16 at its top end, and a screw thread 18 on its outer surface arranged to co-operate with a corresponding thread on the inside of a fuel filler neck 20 which protrudes from the side of a vehicle and forms the end of the fuel filler pipe leading down to the vehicle fuel tank. Towards the lower end of the bore 14 a two-way pressure relief valve 15 is provided which allows air to pass through the cap in either direction provided a sufficient pressure differential has built up.

The cover 12 fits over the top of the body 10 and is connected to the outer edge of the flange 16. The flange 16 has apertures 22 through it which are in communication, via a gap between the cover 12 and the upper edge 24 of the body 10, with the bore 14, thus allowing air to pass under the cover 12 inwards and outwards between the filler pipe and atmosphere.

It can be a problem with this type of cap that, when air flows inwards through the cap into the filler neck, contaminants can be carried with it.

The present invention therefore provides a fuel filler cap comprising a body having an aperture through it, a pressure relief valve to control the flow of air through the aperture, and a cover extending over one end of the aperture, wherein projections are provided on the body and the cover which co-operate to define a labyrinthine path between atmosphere and the valve.

Preferred embodiments of the present invention will now be described by way of example only with reference to Figure 2 of the accompanying drawings.

The fuel filler cap according to the invention is similar in basic construction to the prior art cap of Figure 1. Corresponding parts are indicated by corresponding reference numerals preceded by a 1.

The valve assembly 115 is mounted on an annular flange 126 which projects inwards from the wall of the bore 114 near its lower end 128 furthest from the cover 112. The inner edge 130 of the flange 126 defines an aperture 132, and an annular valve spring seat 134 is positioned above the aperture 132, supported on a tubular support section 135 which extends upwards from the flange 126 at a position near to, but spaced from, its inner edge 130. An annular valve member 136 rests against the upper surface of the flange 126 and is held against it by a spring 137 which is compressed between the valve member 136 and the spring seat 134. A valve shuttle 138 is located in the aperture 139 in the centre of the valve member 136 and is biased upwards against the under side of the valve member 136 by a further spring 140.

It will be appreciated that the valve assembly 115 acts as a two way pressure relief valve. If the pressure in the fuel filler neck becomes higher than that in the cap above the valve assembly 115, by more than an amount determined by the rating of the spring 137, the annular valve member 136 will lift off the flange 126 to relieve the pressure in the neck and tank. If the pressure in the tank and neck becomes lower than that in the cap above the valve assembly 115, then the shuttle 138 will move downwards opening the aperture 139 in the annular valve member 136.

A pair of parallel concentric tubular projections 142,144, which are formed integrally with the cover 112, extend from the under side of the cover 112 down into the bore 114 in the body 110. The outer one 142 is close to the wall of the bore 114

but spaced from it and extends downwards into the gap between the supporting section 135 and the wall of the bore 114, being also spaced from the supporting section 135 and the flange 126. A further pair 146, 148 of projections, parallel to and concentric with the first pair 142, 144, extend upwards from the outer and inner edges respectively of the spring seat 134. The outer one 142 extends upwards between, but spaced from, the first pair of projections 142, 144, and the inner one extends inside the inner one 144 of the first pair. Both stop just short of the under side of the cover 112 so there is a space between their upper ends and the cover 112. The second pair of projections 146, 148 are formed integrally with the body 110, flange 126, supporting section 135 and spring seat 134. The projections 142, 144, 146, 148 define a labyrinthine path between the apertures 122 where the air flows into the cap from atmosphere, and the valve assembly 115.

In use, when the cap is in place covering the end of the filler neck 120, air that flows through the cap and the valve assembly 115 must also flow down round the bottom of each of the downwardly extending projections 142, 144 and up over the top of each of the upwardly extending projections 146, 148 before reaching the valve assembly 115. Therefore any dirt and debris carried in this air is likely to by deposited in the bottom of one of the troughs formed between the projections, and not to reach the valve assembly.

It will be appreciated that the cap according to the embodiment described can be produced by modification of the parts already present in the cap shown in Figure 1.

The cover 112 and body 110 may be rotatable relative to each other. The tubular projections 142, 144, 146, 148 are therefore of circular cross section and concentric with the axis of symmetry of the cover 112 and the body 110. This means that during rotation of the cover 112 relative to the body 110 the projections can rotate also without coming into contact with each other.

Claims

CLAIMS 1. A fuel filler cap comprising a body having an aperture through it, a pressure relief valve to control the flow of air through the aperture, and a cover extending over one end of the aperture, wherein projections are provided on the body and the cover which co-operate to define a labyrinthine path between atmosphere and the valve.
2. A fuel filler cap according to claim 1 wherein the projections are tubular.
3. A fuel filler cap according to claim 1 or claim 2 wherein the projections extend in a direction substantially parallel with the aperture through the body.
4. A fuel filler cap according to any foregoing claim wherein the projections overlap in the axial direction of the cap.
5. A fuel filler cap according to any foregoing claim at least one of the projections extends from the cover into the aperture.
6. A fuel filler cap according to claim 5 wherein at least one of the projections extends from the inside of the bore towards the cover.
7. A fuel filler cap according to claim 6 wherein the body includes a flange on which the valve is mounted, and at least one of the projections extends from the flange towards the cover.
8. A fuel filler cap according to any foregoing claim wherein the body includes an outwardly extending flange having an aperture through it to allow the flow of air between the valve and atmosphere.

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9. A fuel filler cap according to any foregoing claim wherein the projections are each formed integrally with either the body or the cover.
10. A fuel filler cap substantially as described herein with reference to the accompanying drawings.