WO2011158202A2

WO2011158202A2 - A fuel cap

Info

Publication number: WO2011158202A2
Application number: PCT/IB2011/052620
Authority: WO
Inventors: Cobus Kemp; Stephen Mark Leeds; Rodney Glenn Shepherd
Original assignee: Cobus Kemp; Stephen Mark Leeds; Rodney Glenn Shepherd
Priority date: 2010-06-18
Filing date: 2011-06-16
Publication date: 2011-12-22
Also published as: WO2011158202A3

Abstract

The invention relates to a fuel tank filler cap (1) which comprises a tube (2) with one closed end (4) and open end (5), and with a stud (9) in the base of the tube at the closed end (4). The stud (9) is shaped and sized to define an annular space (10) relative to the inner wall of the tube (3) complimentary shaped and sized to the nozzle (11) of a fuel filler tube with a predetermined nozzle diameter and shape, operatively allowing the nozzle (11) to extend into the annular space (10) and over the stud (9) to release the cap (1).

Description

A FUEL CAP

FIELD OF THE INVENTION

This invention relates to a fuel cap, in particular for a motor vehicle fuel tank.

BACKGROUND TO THE INVENTION

Several types of fuel are available for the different types of internal combustion engines, petrol or diesel with varying octane ratings or in the case of diesel sulphur components, which lead to the possibility of fuel mixing, especially with passenger motor vehicles.

The scenario where this most often occurs is at passenger motor vehicle filling stations where both petrol and diesel fuel tanks are available, more particularly at filling pumps for passenger vehicles. Presently there are fewer diesel passenger motor vehicles than petrol passenger vehicles in circulation and most filling stations have several fuel islands with petrol and diesel nozzles next to each other on the same island. This means that a diesel passenger vehicle has to fill up at an island where there are petrol and diesel nozzles available. This increases the possibility for fuel contamination. The nozzle being used to dispense diesel is larger in diameter than the one used to dispense petrol. The reason for this wider diameter diesel nozzle is to prevent frothing of the diesel when it is being pump into a fuel tank, which would happen with a narrow diameter nozzle and filler tube for petrol vehicles. The filler tube of a petrol vehicle is smaller than that of a diesel nozzle, which means it is impossible to insert a diesel nozzle into a petrol tank. This prevents diesel fuel from being pumped into a petrol vehicle. This is not the case in older vehicles prior to the introduction of unleaded fuels, which means it is possible to pump diesel in these older petrol vehicles.

Thus, a modern petrol vehicle filling at an island of fuel pumps which include petrol and diesel nozzles cannot inadvertently be filled up with diesel, since the diesel nozzle simply won't fit into the more narrow petrol filler tube.

However, the opposite is not true. Since the nozzle of a petrol pump is smaller than the diesel filler tube it is possible, and often happens, that petrol is added to the fuel tank of a diesel vehicle. This is exacerbated by the presence of mixed fuel pumps on the islands.

The effect of adding petrol to a diesel engine can be very costly. It could damage very sensitive emission control components. Also, since diesel engines function on the principle of compression combustion, and petrol more readily combusts than diesel, the combustion of petrol in a diesel engine could lead to uncontrolled combustion which creates shock waves that could damage engine parts. Also, diesel acts as a lubricant to the engine parts of a diesel engine and petrol does not. Therefore, the use of petrol in a diesel engine robs the components of their required lubrication and creates excessive wear, which will also damage and eventually destroy such components.

Estimates are that in the UK alone as many as 150 000 drivers annually add petrol to diesel vehicles, with the number growing due to the increase in the number of diesel vehicles on the road. There have been several attempts to overcome this problem, which have met with varying degrees of success. A common problem with some of the solutions presented already includes changes to infrastructure, either to filling station forecourt infrastructure or motor vehicle fuel tank design or both. Other examples exists of attempts to overcome this problem, which in principle all rely on the inclusion of some sort of a blocking mechanism to prevent entry of a fuel pump nozzle into the filler tube of a diesel tank.

US2005/000592 and US6966349 disclose devices that operate on the principle of providing a blocking member in the form of a coaxial tube fitted inside the standard filler tube of a vehicle, with the combined co-axial tubes limiting entry of a petrol nozzle into the filler tube. A problem with this type device is that if a fuel cap still has to be placed on top of the tube, the co-axial tube cannot extend to the mouth of the filler tube, which could allow a petrol nozzle to be inserted partly into the filler tube and opened. To prevent this, the device also requires a gate at its bottom which is depressed by the tip of the nozzle. If this is not opened, then fuel cannot enter the filler tube. This then creates the risk of a blowback of fuel if a petrol pump nozzle is inserted into the diesel filler tube.

A similar approach is disclosed in patent GB2435037 which includes the added feature of a cap that fits over filler tube and allows the co-axial blocking tube to extend to sit flush with the end of the filler tube.

GB2391544 discloses a device which includes a central blocking disc that prevents entry of a narrower diameter petrol nozzle into the filler tube. OBJECT OF THE INVENTION

It is an object of the invention to provide a fuel cap which at least partly overcomes the abovementioned problem. SUMMARY OF THE INVENTION

In accordance with this invention there is provided a fuel tank filler cap comprising a tube with one closed end and open end, and with a stud in the base of the tube at the closed end, the stud shaped and sized to define an annular space relative to the inner wall of the tube complimentary shaped and sized to the nozzle of a fuel filler tube with a predetermined nozzle diameter and shape, operatively allowing the nozzle to extend into the annular space and over the stud to release the cap.

There is further provided for the cap to be released by means of the nozzle engaging a release mechanism for the cap located in the annular space.

There is further provided for the tube to be provided with screw thread on its outer surface complimentary to screw thread within a fuel tank filler opening, and for the stud to be provided with at least one semi-circular slot extending co-axially with the tube, the slot being complimentary shaped and sized to an aerator tube located co-axially within the fuel filler tube to allow the aerator tube to operatively engage the slot when the filler tube is extended into the annular space and to allow the filler tube to rotate cap in either direction, with rotation of the cap in a first direction configured to unscrew the cap from a fuel tank filler opening within which it is rotatably secured and rotation in the second direction configured to screw the cap into a fuel tank filler opening.

There is further provided for the stud to include three semi-circular slots equidistantly spaced apart around the circumference of the stud, and for the stud to preferably be right circular cylindrically shaped, and for the tube to also preferably be right circular cylindrically shaped. There is still further provided for the tube to include a flange proximate its open end and for the cap to be provided with an annular cover rotatably securable over the flange, the cover having a central aperture complimentary to the core of the tube, and for the cap to include a one-way ratchet mechanism between the flange and the cover operatively allowing the cover to freely rotate in the first direction and to engage the flange upon rotation in the second direction.

There is further provided for the cover to axially movable with respect to the flange within predetermined limits and for the cover to be axially resiliently biased away from the flange and limited in axial movement away from the flange through engagement of a rim on a lip on the cover which engages the rim of the flange, and preferably for the cover to be biased away from the flange by means of a spring between them, wherein movement of the cover against the bias allows engagement of teeth on the cover with complimentary teeth on the flange and rotation of the cap in the second direction only. There is further provided for the cap to include a one way pressure regulated valve shaped and configured to operatively allow gas to escape from a fuel tank, and preferably for the valve to be located in the base of the tube with a passage extending through the base, the passage being normally closed by the valve and opened under action of predetermined gas pressure to allow gas to escape from the tank through the passage.

According to a still further feature of the invention there is provided for the core of the tube to be shaped into a set of grooves and lands complimentary to a set of grooves and lands on the outer surface of the fuel filler tube, to operatively allow engagement of the two sets of lands and grooves when the fuel filler tube is inserted into the tube. According to a still further feature of the invention there is provided a key for the cap which comprises a cylindrical shaft complementary shaped and configured to the core of the cap and having a grip extending from its operatively upper surface. These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention is described by way of example only and with reference to the accompanying drawings in which : is a perspective view of a fuel cap according to the invention ; is a sectional perspective view of the fuel cap of Figure 1 including a key; is an elevation of the fuel cap of Figure 1 including a key;

is a view of the fuel cap of Figure 1 proximate a fuel filler tube of a motor vehicle;

shows the fuel cap of Figure 4 secured in position in the filler tube with a fuel pump nozzle proximate the fuel cap; and

shows the nozzle of Figure 5 engaged into the fuel cap to open it.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment of the invention comprises a cap (1 ) which comprises a tube (2) with a central right circular cylindrical core (3) which is closed at one end (4) and open at the opposing end (5). The tube includes external screw thread (6), complimentary to screw thread (7) in a filler tube (8) of a diesel vehicle fuel tank (not shown).

Located centrally in the core (3) at its closed end (4) is a stud (9). The stud (9) is axially aligned with the core (3) and is shaped and sized to define an annular space (10) relative to the inner wall of the core (3), which space (10) is complimentary shaped and sized to the filler tube nozzle (1 1 ) of a diesel fuel nozzle, to operatively allow the nozzle to extend into the annular space (1 1 ) and over the stud and release the cap when rotated anti clockwise from a fuel tank filler tube (8), within which it is operatively rotatably secured. The stud (9) and the core (3) of the tube (2) are right circular cylindrically shaped. The stud (9) includes three semi-circular slots (12) equidistantly spaced apart around the circumference of the stud (9) and extending co-axially with the tube (2). The slots (12) are complimentary shaped and sized to an aerator tube (not shown) located co-axially within the fuel filler nozzle (1 1 ) to allow the aerator tube to operatively engage one of the three slots (12) when the nozzle (1 1 ) is extended into the core (3) and the annular space (10) therein. The core (3) of also includes a set of co-axial grooves (13) and lands (14) complimentary to a set of lands (15) and grooves (16) on the outer surface of the fuel filler nozzle (1 1 ), to operatively allow engagement of the two sets of lands and grooves when the fuel filler nozzle (1 1 ) is inserted into the core (3). The two sets of engaging features, namely the aerator tube and slots (12) and the lands (14, 1 5) and grooves (13, 16), allow the fuel filler nozzle (1 1 ) and fuel cap (1 ) to positively engage each other. This allows the nozzle (1 1 ) to rotate the cap (1 ) in either direction. Simultaneous rotation of the nozzle and cap in the anti-clockwise direction unscrews the cap (1 ) from the filler opening (8) and rotation in the clockwise direction screws the cap (1 ) into the filler opening (8).

The nozzle (1 1 ) of a fuel pump is thus used to unscrew the cap (1 ) from the filler opening (8). The cap can be unscrewed only by means of the fuel nozzle. Tightening occurs by way of the fuel nozzle or by hand, the latter being made possible through the one way ratchet mechanism.

To facilitate easy closure of the cap (1 ) the tube (2) also includes a flange (17) proximate its open end (5). An annular cover (18) is located over the flange (17), and the cover (18) includes a central aperture (19) complimentary to the core (3) of the tube (2) so as not to obstruct the core (3).

The cover (18) is rotatably secured over the flange (17), with a rim (20) on the lip (21 ) of the cover (18) being engaged over the rim (22) of the flange (17). The cap (1 ) includes between the cover (18) and flange (17) a one way ratchet mechanism in the form of a set of complimentary teeth with one set of teeth (23) on the operatively inside surface of the cover and the other set of teeth (24) on the operatively upper surface of the flange (1 7). The sets of teeth (23, 24) are ramped on one side each and are configured for the ramps to ride over each other upon rotation on the cover in first direction and for the teeth (23, 24) to engage each other upon rotation of the cover in the second direction. There is limited axial movement between the cover (1 8) and the flange (17) which is limited on the one end by abutment of the cover rim (20) with the flange rim (22), and at the other end by abutment of the sets of teeth (23, 24). The cap (1 ) also includes a helical spring (25) between the cover (1 8) and flange (17) which biases the cover (18) away from the flange (1 7) to keep the sets of teeth out of engagement unless the cover (18) is depressed against the spring (25) bias.

The cap (1 ) also includes a conventional one way pressure regulated valve (26) at its closed end (4). The cap (1 ) includes a pressure relief passage (27) centrally in its base which extends through the stud (9). The passage (27) is normally closed by the valve (26), but opens at a predetermined gas pressure to allow gas to escape from the fuel tank connected to the fuel filler tube (27). This prevents dangerous build up of gas within the fuel tank.

The cap also includes a key (28) which allows manual removal of the cap from a fuel filler tube (8), and for its securing therein. The key (28) includes a cylindrical shaft (29) complementary shaped and configured to the core (3) of the cap (1 ) and a grip (30) which extends from the operatively upper surface of the key (28). The shaft (29) of the key (28) includes grooves (not shown) and lands (not shown) which matches the lands (14) and grooves (15) in the core (3). The key (28) may be inserted up to the grip (30) into the core (3) and rotated in either direction by the grip (30). This allows the opening or closing of the cap (1 ) by means of the key (28).

By making use of a cap according to the invention it is possible to prevent inadvertent filling of a diesel vehicle with petrol, since the petrol pump nozzle is not able to release the cap from the filler tube. The narrower diameter nozzle of the petrol pump will simply rotate freely upon the stud (9) in the cap without unscrewing it. Even if the fuel pump is then opened, fuel would still not flow into the diesel tank since the cap is still in place. (The fuel cap of the vehicle can not be opened/released by hand)

Only once a fuel attendant has taken a diesel pump nozzle and removed the cap using it, will he be able to fill the diesel tank. By then he will already have the diesel pump nozzle in his hand and would have to deliberately replace it and take a petrol nozzle out of its location on another pump to get petrol into the diesel tank. This will not happen inadvertently.

It will be appreciated that the invention is not limited to the specific embodiment described above. It is possible to change aspects of this embodiment without departing from the scope of the invention. It is for example possible to include a normal key and lock into the cap which will operate to secure the cap in cars which do not have lockable filler tube cover plates.

It is also possible to include a release mechanism which operates on a pressure sensitive mechanism located in the annular space between the stud and the core of the tube. This could allow the cap to be released by means of a mechanism that is triggered by the end of the diesel fuel nozzle when it extends into the space, a space which is not accessible to a petrol pump nozzle. The invention therefore provides a fuel cap which at least partly eliminates accidental fuel contamination. This is achieved by a cap that allows opening only through the diesel fuel nozzle, but still allowing closing thereof by hand. Substantive issues of human error and incorrect fuel types are eliminated, as well as the repair costs involved to rectify this error.

Claims

A fuel tank filler cap comprising a tube with one closed end and open end, and with a stud in the base of the tube at the closed end, the stud shaped and sized to define an annular space relative to the inner wall of the tube complimentary shaped and sized to the nozzle of a fuel filler tube with a predetermined nozzle diameter and shape, operatively allowing the nozzle to extend into the annular space and over the stud to release the cap.

A fuel tank filler cap as claimed in claim 1 wherein the cap is released by means of the nozzle engaging a release mechanism for the cap located in the annular space.

A fuel tank filler cap as claimed in claim 1 or 2 wherein the tube is provided with screw thread on its outer surface complimentary to screw thread within a fuel tank filler opening, and wherein the stud is provided with at least one semi-circular slot extending co-axially with the tube, the slot being complimentary shaped and sized to an aerator tube located co-axially within the fuel filler tube to allow the aerator tube to operatively engage the slot when the filler tube is extended into the annular space and to allow the filler tube to rotate cap in either direction, with rotation of the cap in a first direction configured to unscrew the cap from a fuel tank filler opening within which it is rotatably secured and rotation in the second direction configured to screw the cap into a fuel tank filler opening.

A fuel tank filler cap as claimed in any of the preceding claims wherein the stud includes three semi-circular slots equidistantly spaced apart around the circumference of the stud.

A fuel tank filler cap as claimed in any of the preceding claims wherein the stud and tube is right circular cylindrically shaped.

A fuel tank filler cap as claimed in any of the preceding claims wherein the tube includes a flange proximate its open end and wherein the cap is provided with an annular cover rotatably securable over the flange, the cover having a central aperture complimentary to the core of the tube, and wherein the cap includes a one-way ratchet mechanism between the flange and the cover operatively allowing the cover to freely rotate in the first direction and to engage the flange upon rotation in the second direction.

7. A fuel tank filler cap as claimed in claim 6 wherein the cover is axially movable with respect to the flange within predetermined limits and wherein the cover is axially resiliently biased away from the flange and limited in axial movement away from the flange through engagement of a rim on a lip on the cover which engages the rim of the flange, wherein movement of the cover against the bias allows engagement of teeth on the cover with complimentary teeth on the flange and rotation of the cap in the second direction only.

8. A fuel tank filler cap as claimed in claim 7 wherein the cover is biased away from the flange by means of a spring.

9. A fuel tank filler cap as claimed in any of the preceding claims wherein the cap includes a one way pressure regulated valve shaped and configured to operatively allow gas to escape from a fuel tank.

1 0. A fuel tank filler cap as claimed in claim 9 wherein the valve is located in the base of the tube with a passage extending through the base, the passage being normally closed by the valve and opened under action of predetermined gas pressure to allow gas to escape from the tank through the passage.

1 1 . A fuel tank filler cap as claimed in any of claims 6 to 1 0 wherein the core of the tube is shaped into a set of grooves and lands complimentary to a set of grooves and lands on the outer surface of the fuel filler tube, to operatively allow engagement of the two sets of lands and grooves when the fuel filler tube is inserted into the tube.

12. A fuel tank filler cap as claimed in any of the preceding claims including a key for the cap which comprises a cylindrical shaft complementary shaped and configured to the core of the cap and having a grip extending from its operatively upper surface.