RESTRICTOR DEVICE FOR A FUEL TANK

The present invention relates to a restrictor device for controlling the flow of fluid into and out of a fuel tank, and also to a fuel tank and a vehicle including the restrictor device.

Motor vehicles include fuel tanks for storing diesel, petrol or other liquid fuel. A typical fuel tank comprises a large substantially cuboid or cylindrical storage vessel for storing the fuel, a neck portion having an aperture formed therein, which defines an ingress or fuel insertion port, and a closure member such as a cap that is fitted to the neck portion. Typically the cap includes an internal screw thread that is arranged to mate with an external screw thread on the neck portion. The screw cap prevents fuel from spilling out of the tank when securely located in place. However, sometimes drivers forget to replace the screw cap or apply it incorrectly such that the fuel tank is not properly sealed. This is a particular problem for lorries that have one or more large diesel tanks without any additional shrouding. If the cap is not properly applied to the neck, fuel can spill out, particularly when driving round corners or roundabouts, since the forces generated can cause fuel to rise up the neck and to spill onto the road surface. This loss of fuel can be very hazardous for other road users, particularly motorcyclists, who often skid because of fuel spillages. This can lead to serious injury or even death. Therefore there is a need to find an alternative to the screw cap or to provide an additional device that prevents the spillage of fuel when the screw cap is not fitted properly.

Another problem with known fuel tanks is that it is possible to overfill them by withdrawing the fuel pump nozzle as the fuel approaches the neck. This prevents the automatic cut-out mechanism in the pump from operating. This is undesirable since spilt fuel poses a significant fire risk at fuel stations and requires attendants to treat or remove the spilt fuel. Also, the driver has to pay for fuel that he cannot use.

The first problem has been addressed to some extent by the inclusion of a spring loaded flap at the base of the filler neck in some petrol tanks. The resiliency of the spring holds the flap across the neck thereby preventing fuel from exiting the tank. However, it is difficult for this type of arrangement to obtain a good seal and therefore small amounts of fuel can escape the tank if the cap is not attached properly. Also, the device does not properly address the problem of overfilling of the tank.

Accordingly, the present invention seeks to mitigate at least one of the above-mentioned problems, or at least to provide an alternative to the known systems.

According to one aspect of the invention there is provided a restrictor device for restricting the flow of fuel into and out of a fuel tank, said fuel tank having an ingress for receiving fuel, wherein the device includes a closure member that is arranged to move with respect to the ingress from a first operational position wherein the ingress is open to a second operational position wherein the ingress is closed, and an actuator device for moving the closure member to the open position in response to a user inserting a fuel pump nozzle into the fuel tank ingress.

When in the open position, fuel can be pumped into the tank. When in the closed position, the tank is sealed.

Advantageously the actuator device can be arranged to drive the closure member to the closed position when the fuel pump nozzle is removed from the fuel tank ingress.

Advantageously the actuator device can include an actuator member arranged to drive the closure member translationally out of the closed position in response to a user inserting a fuel pump nozzle into the fuel tank ingress. For example, the actuator member can be arranged to push the closure member out of the closed position. Advantageously the actuator member is arranged to allow liquid fuel to pass through it. Advantageously at least part of the actuator member can be tubular. Preferably the tubular part of the actuator member is arranged co-axially with the fuel tank ingress such that during a fuel filling operation fuel is able to flow through the tubular member

into the fuel tank. Advantageously the actuator member can include an actuator element mounted within the tubular part. The actuator element can include a central hub part and a plurality of arms that extend radially outwards from the hub part. Advantageously the liquid fuel can pass through the gaps between the actuator element arms when pumped into the tank. Advantageously the actuator member can include a drive member for driving the closure member, which is arranged in a fixed relationship with the tubular part. Preferably the drive member is arranged substantially co-axially with the tubular part.

Advantageously the actuator device can include biasing means for biasing the closure member into the closed position. Thus the closure member remains in the closed position until a user inserts a fuel pump nozzle into the fuel tank ingress. Advantageously the biasing means can include resilient means arranged to bias the closure member into its closed position. When the fuel pump nozzle is inserted into the ingress, the actuator member is moved along a substantially rectilinear path, the movement of which compresses the resilient means. When the fuel pump nozzle is removed, the resilient means urges the actuator member back along the same path to its closed position. Advantageously the actuator member can be arranged to pull the closure member into its closed position under the action of the resilient means. Advantageously the biasing means can be arranged to act on the actuator member.

Advantageously the closure member can be constructed and arranged to float with the rising fuel level in the fuel tank. This can help prevent the fuel tank from being overfilled. Advantageously the closure member can be arranged to move translationally relative to the actuator member. For example, the closure member can be slideably mounted on the actuator member and is arranged for limited axial movement relative thereto. When the fuel pump nozzle is inserted into the fuel tank ingress it causes the actuator member to push the closure member into the open position, which is preferably downwards into the fuel tank. As the level of fuel approaches the ingress it meets the closure member and causes it to slide along the actuator member until it engages the fuel tank ingress at which point the tank is full (a predetermined maximum level). At

this time, the automatic cut-out in the fuel pump is tripped and no more fuel is pumped into the tank.

Alternatively the translational position of the closure member can be fixed relative to the actuator member such that the closure member moves with the actuator member.

Advantageously the restrictor device can include means for enabling air to flow into the fuel tank as the fuel is used up. This prevents a vacuum from forming in the fuel tank. Advantageously the air can enter the fuel tank by breaking the seal between the closure member and the ingress. Preferably the restrictor device includes resilient means for biasing the closure member into the closed position, wherein the resilient means is arranged such that the closure member breaks its seal with the fuel tank ingress to enable air to enter the fuel tank via the gap(s) between the ingress and the closure member when the suction force generated by negative pressure inside the fuel tank is greater than the biasing force of the resilient means. The strength of the resilient means is selected accordingly. Advantageously the resilient means can be the biasing means used to bias the closure member into the closed position and/or a second resilient means acting between the closure member and the actuator member. For example, in one embodiment a large helical spring is used to bias the closure member into the closed position and a second smaller helical spring is located on the actuator member between an end stop and the free moving closure member. The large helical spring is mainly used to strongly urge the closure member against the fuel tank ingress to seal the tank and the smaller spring is arranged to allow some relative movement between the closure member and the actuator member when the closure member is in the closed position. Thus a negative pressure in the fuel tank, which can occur when fuel is drained from the tank when a vehicle is operating, can overcome the smaller spring to enable the seal between the closure member and the fuel tank ingress to allow air to be drawn into the tank via the ingress to reduce the negative pressure.

Advantageously the restrictor device can include a support assembly for supporting the actuator device. The support assembly can include a tubular housing for housing the actuator device. Advantageously the tubular housing can be arranged to fit into the fuel

tank ingress such that it is arranged co-axially with the actuator member. The position of the tubular housing is fixed relative to the fuel tank ingress and the actuator member is arranged for limited translational movement within the tubular housing. Advantageously the limited translational movement can be a long an axis that is coaxial with, or is substantially parallel with, the longitudinal axis of the tubular housing.

Advantageously the restrictor device can include at least one air pathway to enable air to exit the fuel tank during a fuel insertion process. The or each air pathway is separate from the pathway that the fuel flows along when inserted into the fuel tank. The or each air pathway can include air holes formed in the tubular housing. The air holes are arranged close to the exit of the fuel tank ingress to ensure that when a fuel pump nozzle is inserted into the ingress the end of the nozzle is located beyond the air holes. This allows the air to escape the fuel tank beyond the leading end of the fuel pump nozzle thereby preventing the fuel pump cut-out mechanism from tripping.

The restrictor device can include means for closing the or each air pathway when the closure member is in the closed position to prevent air and fuel from escaping the fuel tank. Advantageously the actuator member can be arranged to seal the or each air pathway when the closure member is in the closed position. For example, the actuator member can be arranged to seal the air holes in the tubular housing.

The support assembly can include an annular support member for restricting the lateral movement of the tubular housing within the fuel tank ingress. Advantageously the annular support member can include at least one pathway formed therein to allow air to pass between the fuel tank body and the tubular housing. For example, the annular support member may include holes, grooves or slots formed therein. Advantageously the or each pathway is arranged to allow air to pass along them but to prevent liquid fuel from passing through the annular support member. For example the holes, grooves or slots may include a gauze or filter, which allows air to pass through but prevents liquid fuel from passing through.

The restrictor device can include at least one filter member for filtering the fuel pumped into the tank. Advantageously the restrictor device can include first and second filter members. Preferably a first filter member is located in the tubular housing. Preferably a second filter member is attached to the actuator member.

According to another aspect of the invention there is provided a fuel tank including a restrictor device according to any configuration described herein.

According to another aspect of the invention there is provided a vehicle including a fuel tank and a restrictor device according to any configuration described herein.

An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side sectional view of a restrictor device in accordance with the invention located in a filler neck of a fuel tank in a first operational condition; and

Figure 2 is a side sectional view of the restrictor device of Figure 1 in a second operational condition.

Figure 1 shows a restrictor device 1 securely located in the neck 3 of a fuel tank 5. The device may be included in a fuel tank at the time of construction of a new vehicle or alternatively can be retrofitted at a later date. In either case, it is intended that the restrictor device 1 will be sufficiently secure to prevent its unauthorised removal, for example the restrictor device 1 could be welded into place.

The restrictor device 1 includes a first part Ia that has a fixed position relative to the fuel tank 5 and a second part Ib that is able to move relative to the fuel tank 5 (and hence the first part Ia).

The first part Ia of the restrictor device includes a substantially cylindrical outer sleeve member 7, an inner support ring 9 for attaching a support element 19 to the outer sleeve member 7, and a collar 13.

The outer sleeve 7 fits into the filler neck 3 and includes a flange 7b for abutting the upper end of the neck 3 and fixing its longitudinal position relative to the tank 5. The outer sleeve 7 is supported by the collar 13, which prevents the outer sleeve 7 from moving laterally within the neck 3. The outer sleeve 7 also includes six apertures 15 formed in the curved surface of the sleeve, which are air holes for providing part of an air pathway between the interior of the fuel tank and atmosphere when the apertures 15 are exposed to atmosphere. The apertures 15 are located towards the upper end of the outer sleeve 7 and are evenly distributed circumferentially about the sleeve. The position of the apertures 15 ensures that during a filling operation air can escape the tank 5 above the filler nozzle. The collar 13 is designed to allow air to pass through its structure, for example it may include a number of holes or slots formed therein, which can optionally be covered by a gauze or mesh that allows air to pass there through but not liquid fuel. This allows air into and out of the fuel tank 5 via the apertures 15 when the apertures 15 are exposed to atmosphere.

The support ring 9 fits into the outer sleeve 7 in a tight fitting manner and is arranged co-axially therewith. The support ring 9 is fixed in place towards the lower end of the sleeve 7, for example via a tongue and groove arrangement 17. The support element 19 is attached to the outer sleeve 7 by the support ring 9. The support element 19 includes a number of spokes 21 extending radially inwards from the ring 9 to a hub 23. Filter segments (not shown) can be located between each of the spokes 21 so that the support element 19 can also act as a filter for removing particulate contamination from the liquid fuel.

The second part Ib of the restrictor includes an inner sleeve member 25, an actuator element 27, a large helical spring 29, a drive rod 31 having a stop member 33, a closure element 35 and a small spring 37. The second part Ib of the restrictor is arranged to seal the fuel tank 5 in an openable manner.

The inner sleeve 25 is located within the outer sleeve 7, coaxially therewith. The inner sleeve 25 is arranged for limited axial movement within the outer sleeve 7 from a "closed" position, wherein the inner sleeve 25 abuts a shoulder 39 formed in the inner

surface of the outer sleeve 7 (see Figure 1) and an "open" position, which is axially displaced from the closed position in the direction of the fuel tank, wherein the extent of movement is mostly determined by the fuel pump nozzle being fully inserted into the neck 3 of the tank. When in the open position, the inner sleeve 25 exposes the apertures 15 to atmosphere, thereby creating an air pathway from the interior of the fuel tank 5 to the atmosphere. When in the closed position, the inner sleeve 25 seals the apertures 15.

The actuator element 27 is fixed to the inner sleeve 25. The actuator element 27 has a similar structure to the support element 19 (i.e. includes spokes 21, a hub 23 and optionally may include filter segments (not shown)). The drive rod 31 is located coaxially with the inner sleeve member 25 and passes through the hubs 23 of the support and actuator elements 19,27. The drive rod 31 is fixed to the actuator element 27 but can move axially relative to the support element 19, thus the inner sleeve 25, the actuator element 27 and the drive rod 31 are arranged to move as a unit, to open and close the fuel tank 5.

The closure element 35 is used to seal the fuel tank 5. The closure element 35 has a main body portion 35a, which includes a substantially conical outer shell 35b for providing a good seal with the lower end of the outer sleeve 7, and a substantially cylindrical tubular portion 35c for connecting to the drive rod 31, which extends above and below the outer shell 35b. The closure element 35 is mounted on the drive shaft 31 via the tubular portion 35c and is arranged to slide axially along the drive shaft 31. The sliding movement is limited by a stop member 33 at one end of the drive shaft and the support element 19. A small helical spring 37 is located between the stop 33 and the underside of the conical shell 35b for biasing the closure element 35 towards the lower end of outer sleeve when in the closed position.

The large helical spring 29 is located coaxially with the inner sleeve 25 and is positioned between the support and actuator elements 19,27. The large spring 29 is arranged to bias the inner sleeve 25, and hence the closure member 35, to the closed position (see Figure 1). The closure member 35 is moved to the open position (see Figure 2) by the insertion of a fuel pump nozzle driving the actuator element 27, and

hence the inner sleeve 25 and drive rod 31, into the fuel tank 5, thereby compressing the large spring 29.

When in the closed position the closure element 35 abuts the lower end of the outer sleeve member, thereby sealing the filler neck 3. In this condition, the small spring 37 is partially compressed between the underside of the closure element 35 and the stop member 33. If a vacuum should form in the fuel tank 5 as fuel is removed, when the vacuum force exceeds the force exerted by the small spring 37 the closure element 35 disengages the lower end of the outer sleeve 7 thereby breaking the fuel tank seal and allows air to flow into the fuel tank 5 via the gap between the outer sleeve 7 and the closure element 35. When the pressure in the fuel tank increases, the biasing of the spring 27 causes the closure element to seal the fuel tank again.

The operation of the restrictor device 1 will now be described. During normal driving conditions the restrictor device will be in a closed position shown in Figure 1. In this position no fluid can enter or leave the fuel tank 5 since the main fluid entry is closed by the closure element 35 sealing the lower end of the outer sleeve 7 and the inner sleeve 25 sealing the apertures 15 thereby closing the air pathway to the fuel tank 5. Thus no fluid can enter or exit the fuel tank 5. This operation condition holds unless a negative pressure occurs in the fuel tank (see below).

During a filling operation, a user pushes the fuel pump nozzle into the outer sleeve 7. The leading end of the nozzle abuts the actuator element 27 such that pushing the fuel pump nozzle into the neck 3 drives the actuator element 27, into the fuel tank 5 against the resiliency of the large spring 29, thereby driving the inner sleeve 25, the drive rod 31 and closure member 35 into the tank 5 until the fuel pump nozzle is fully inserted into the filler neck 3. In this condition, an air pathway is created between atmosphere and the fuel tank 5 via the gap between the outer sleeve 7, the fuel tank neck 3, the gaps in collar 13 and the apertures 15. Movement of the inner sleeve 25 to the open position causes the drive rod 31 to push the closure element 35 out of sealing engagement with the lower end of the outer sleeve 7. Thus fuel can be pumped into the fuel tank through

the support and actuator elements 19,27 and over the upper surface 35b of the closure element.

At this time the, closure element 35 is located towards the stop member 33 on the drive rod 31.

As the fuel level rises within the fuel tank 5, the fuel level causes the closure element 35 to move axially along the drive rod 31 away from the stop member 33 until it engages the lower end of the outer sleeve 7. When this happens, the automatic cut-out in the fuel pump trips, which prevents additional fuel from being pumped into the tank 5. As the user withdraws the fuel pump nozzle, the biasing of the helical spring 29 causes the inner sleeve 25, the actuator element 27 and the drive rod 31 to move to the closed position, which enables the large and small springs 29,37 to bias the closure element 35 against the outer sleeve 7 thereby sealing the fuel tank 5.

If the user tries to continue to pump fuel into the tank 5 while withdrawing the nozzle (so called "necking") the fuel accumulates within the neck 3 and quickly causes the automatic pump trip-out switch to operate. This prevents overfilling of the tank 5.

As fuel is consumed by the vehicle a negative pressure can occur in the fuel tank 5. If the negative pressure generates a force that is sufficiently large to overcome the force exerted on the closure member 35 by the small spring 37 the fuel tank seal will be broken an air enters the fuel tank 5 through the neck 3 via the gap between the closure member 35 and the outer sleeve 7. This reduces the negative pressure in the fuel tank 5. The closure device allows residual fuel to drain from the filler neck into the tank since the dual spring mechanism facilitates this, for example when air seal is broken to relieve pressure.

It will be appreciated by the skilled person that changes can be made to the above embodiment that fall within the scope of the invention, and that the invention is not to be considered as being limited to that embodiment. For example, it is not strictly necessary to use large and small springs. It is envisaged that in at least some

embodiments it will be possible to use a single spring for biasing the closure member 35 into sealing engagement which is sufficiently strong to return the inner sleeve 25, actuator element 27 and drive rod 31 to the start position but also enables air to flow into the tank to prevent a vacuum from forming.

The closure member 35 can be fixed to the drive rod 31 instead of being arranged to slide along it. In this arrangement, the fuel tank remains open during a filling operation until the fuel pump nozzle is withdrawn from the filler neck 3.

The closure member 35 is not limited to a substantially conical shape, for example it can be any suitable shape such as substantially dome shaped.

The construction of the restrictor device allows retrospective fitting to existing vehicle fuel tanks, since it comprises a sleeve having a number internal components that can fit into the neck of an existing fuel tank.

The closure assembly presents minimal restriction to the ingress of fuel. This is because the actuator arrangement pushes the closure element 27 out of the way when the nozzle is pushed into the fuel tank. This accommodates a high delivery rate for commercial refueling systems.

The support assembly and/or the actuator arrangement prevents siphoning of fuel from the tank. In the embodiment described above, the support and actuator elements 19,27 prevent a siphoning tube from being inserted into the tank.

Another advantage of the invention is that the closure element 35 is arranged to increase the seal of the restrictor device in response to the force of fuel trying to escape from the tank. This occurs since the weight of the fuel pushes the closure element 35 more tightly against the outer sleeve 7.