A fuel tank for a vehicle

Abstract

Aspects of the present invention relate to a fuel tank for a vehicle, comprising: a fuel bladder; a protective shell enveloping the fuel bladder, the protective shell formed of a top panel, a rear pan

Description

TECHNICAL FIELD The present disclosure relates to a fuel tank. Aspects of the invention relate to a fuel tank, a vehicle comprising the fuel tank, and a method of assembling the vehicle. BACKGROUND It is known to fit auxiliary fuel tanks in vehicles to increase their range, for example for long-distance racing. The size and geometry of the auxiliary fuel tank will be arranged to allow for ease of installation into the vehicle, whilst making most efficient use of the available space within the vehicle. These are generally competing requirements, with a fuel tank that efficiently uses the available space generally having a more complex geometry and this can make installation more difficult. These difficulties can be exacerbated as the complexity of the vehicle structure and sub-structure increases, for instance bulkheads and roll over protection structures can further limit the available space. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a fuel tank, a vehicle comprising a fuel tank, and a method of assembling a vehicle comprising the fuel tank as claimed in the appended claims. According to an aspect of the present invention there is provided a fuel tank for a vehicle, comprising: a fuel bladder; a protective shell enveloping the fuel bladder, the protective shell formed of a top panel, a rear panel, a bottom panel, a front panel, a first side panel, and a second side panel fastened together; and a fuel interaction assembly of the fuel bladder extending through the top panel of the protective shell. A fuel interaction assembly is a device forming an interface for the fuel bladder. Typically, a fuel interaction assembly includes a plate for attaching to the protective shell enveloping the fuel bladder, with the plate forming a mounting surface onto which one or more fuel interaction features are mounted. The plate may be a rigid plate with fuel interaction features extending through the surface of the plate. Such features may include a fuel level sender unit, an outlet, vent, filler cap, high pressure pumps, and a surge tank. The fuel interaction assembly may be known in the art by various names such as a competition fuel cell unit, fill plate and top plate. With this arrangement, a multi-part protective shell is provided that can be assembled within a vehicle. The maximum dimensions of the fuel tank are therefore increased due to the reduced need to consider inserting a fully assembled fuel tank into the vehicle (i.e. herein referred to a fuel tank enclosure of the vehicle). The first side panel and the second side panel may be spaced by a first width towards the rear panel and a second, smaller, width towards the front panel, with a stepped transition between the first and second widths defining a stepped portion of the fuel tank for accommodating an inclined portion of a roll over protection structure. The multi-panel structure of the protective shell allows complicated geometries to be manufactured and assembled more easily, for example to accommodate the configuration of an existing roll over protection structure. The fuel tank may comprise a corner brace within the stepped portion of each of the first side panel and the second side panel. This helps to support the protective shell at the stepped portion, with the stepped portion able to accommodate the positioning of other features such as the roll over protection structure. The top panel may comprise a first top panel section and a second top panel section integrally formed and angled relative to each other at an obtuse angle. The inclined top panel can accommodate the positing of other features such as the roll over protection structure, as well as provide a convenient location for a viewing window for viewing the fuel bladder certification label. The rear panel may be a two-part rear panel comprising a first rear panel section and a second rear panel section fastened to the first rear panel section at a convex edge extending between the first and second side panels. The multi-part fuel tank allows more complicated fuel tank geometries to be manufactured and assembled so as to accurately size to the available geometry. The fuel tank may comprise a strap extending laterally across the first side panel, front panel, and second side panel, and fastened at both ends to the rear panel. The strap can help to support the fuel tank. According to an aspect of the present invention there is provided a vehicle comprising the fuel tank. The bottom panel may be fastened to a main structure of the vehicle. The rear panel may be fastened to a bulkhead of the vehicle. This helps to support the fuel tank. The vehicle may comprise a roll over protection structure having a plurality of tubular members defining a fuel tank enclosure in which the fuel tank is confined, wherein two rear tubular members of the plurality of tubular members are located towards a rear of the vehicle and extend from the main structure to an upper position of the roll over protection structure at an acute angle to a vertical axis of the vehicle. A roll over protection structure can dictate the available geometry of the fuel tank as it defines the fuel tank enclosure. A multi-part fuel tank protective shell can be particularly advantageous in terms of assembly within such a structure. The rear tubular members extend across and generally parallel to a plane of the second top panel section. As a result, the top panel is arranged to maximise the use of space by inclining at the same angle as the tubular members. One of the rear tubular members may extend through the first stepped portion of the fuel tank and / or the other of the rear tubular members may extend through the second stepped portion of the fuel tank. The stepped portion accommodates for the position of the rear tubular members. The vehicle may comprise a fuel tank mount frame mounted on the top panel, the fuel tank mount frame comprising a lateral brace member extending between the rear tubular members. The lateral brace fixes the fuel tank to the roll over protection structure and can help to support the fuel tank. The rear tubular members may be angled towards each other so as to form an inverted ‘V’ configuration. A ‘V’ configuration generally provides improved access to the top of the fuel tank compared to an ‘X’ configuration. The rear tubular members may be removably attached to a main roll over protection structure. This further helps in maximising the ease of assembly of the fuel tank within the fuel tank enclosure of the roll over protection structure. According to an aspect of the present invention there is provided a method of assembling the vehicle. The method comprises: inserting the top, rear, bottom, front, first side, and second side panels into the fuel tank enclosure of the roll over protection structure; inserting the fuel bladder into the fuel tank enclosure; fastening the panels together within the fuel tank enclosure to form the protective shell enveloping the fuel bladder; and, fastening the protective shell to the main structure and / or bulkhead (80) of the vehicle. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a fuel tank according to an embodiment of the invention; Figure 2 shows a fuel interaction assembly of the fuel tank located on a top panel of the fuel tank; Figure 3 shows a perspective view of the fuel tank showing the rear panel; Figure 4 shows the fuel tank in-situ within a fuel tank enclosure defined by a roll over protection structure; Figure 5 shows the roll over protection structure; Figure 6 shows a bulkhead of the vehicle; Figure 7 shows a vehicle in accordance with an embodiment of the invention. DETAILED DESCRIPTION A fuel tank 10 in accordance with an embodiment of the present invention is described herein with reference to the accompanying Figures 1 to 7. As shown in Figure 7, the fuel tank 10 is installed in a vehicle 100. Figure 1 illustrates the fuel tank 10. The fuel tank 10 includes a fuel bladder 28 enveloped by a protective shell 12. The fuel bladder 28 is arranged to contain a fuel suitable for feeding an engine of the vehicle 100. The fuel tank 10 is typically an auxiliary fuel tank 10 arranged to supplement the fuel held in a main tank (not shown) of the vehicle 100 to extend the vehicle range. The auxiliary fuel tank 10 is preferably arranged to contain a large volume of fuel, for instance a larger volume than the main fuel tank and will therefore occupy a significant portion of the vehicle interior volume. This presents a number of challenges related to the design, manufacture and assembly of the fuel tank 10 into the vehicle 100. The protective shell 12 is formed of an assembly of panels that include a top panel 21, a rear panel 22 (shown most clearly in Figure 4), a bottom panel 23, a front panel 24, a first side panel 25, and a second side panel 26 each fastened together by fasteners 13a. The fuel tank, and in particular the fuel bladder 28, can be filled with a fuel via an inlet 15, such as the inlet 15 that extends through the top panel 21. The top panel 21 includes an opening through which a fuel interaction assembly 30 extends. As shown by way of example in Figure 2, the fuel interaction assembly 30 includes a plate 31 attached to the top panel 21 by a plurality of fasteners 13b. The fuel interaction assembly 30 acts as an interface across the protective shell 12 to the fuel in the fuel tank 10 and includes one or more fuel interaction features, such as a fuel level sender unit 32, an outlet(s) 33, fuel return 35 and / or vent 34 that are shown by way of example in Figure 2, although it will be appreciated the fuel interaction assembly 30 may include various additional features including, but not limited to, a surge tank, fuel pumps, high pressure pumps, electrical connections and filler cap. An auxiliary fuel tank is typically installed at a relatively late stage of assembly, or after-market. As a result, the fuel tank is sized not only to fit within the available space of the vehicle 100 but also sized for installation from outside the vehicle 100 into the fuel tanks intended installation position. Accordingly, conventional fuel tanks are suitably sized for installation within these geometrical restraints. By providing a multi-part protective shell 12, the constraints on the size of the fuel tanks 10 are reduced due to the ability to assemble the fuel tank 10 in-situ, i.e. the panels are assembled inside the vehicle 100. It will be appreciated that each of the abovementioned panels 21,22, 23, 24, 25, 26 may be integral panels or formed of separable sub-panels, as examples referred to below will demonstrate. The geometry of the fuel tank 10 is dimensioned to maximise the use of available space within the vehicle 100. To do this, the fuel tank 10 may have an irregular (i.e. non-cuboidal) shape, for example with angled sides, inclined and inflected portions, such as will be described below. As indicated in Figure 2, the first side panel 25 and second side panel 26 are spaced by a first width W1 towards the rear panel 22 and spaced by a second, smaller, width \N2 towards the front panel 24, with a stepped transition between the first and second widths W1, W2 defining a stepped portion of the fuel tank 10. This stepped portion accommodates the position of a roll over protection structure 70, as will be described in further detail in relation to Figure 4. The first and second side panels 25a, 25b may be integrally formed, such as shown, or separately formed and fastened together. The stepped portion is supported by a corner brace 16 located therein. The corner brace 16 is a generally triangular reinforcing member that reinforces the protective shell 12 at the stepped portion. Additional support for the protective shell 12 may be provided by a strap 17. The strap extends laterally across the first side panel 25, the front panel 24, and the second side panel 26, with the strap 17 fastened at both ends to the rear panel 22. The bottom panel 23 of the protective shell 12 is fastened to the main structure of the vehicle (for example a vehicle chassis or vehicle frame), either directly or indirectly. In Figures 3 and 4 the protective shell 12 is shown to include first and second beams 18a, 18b attached to the bottom panel 23. In turn, these beams 18a, 18a are attached to the vehicle frame. It will be appreciated that the protective shell 12 may be attached to any part of the main structure of the vehicle 100, for example the vehicle chassis. The vehicle 100 includes a roll over protection structure 70 (alternatively know as a roll cage), such as shown in Figure 4. The roll over protection structure 70 includes a plurality of tubular members 71. One or more of the tubular members 71 may be joined together by releasable connectors 72. The roll over protection structure 70 defines a fuel tank enclosure in which the fuel tank 10 is constrained, i.e. the roll over protection structure 70 prevents the fuel tank 10 from exiting the fuel tank enclosure when the roll over protection structure 70 is fully assembled. The roll over protection structure 70 includes two rear tubular members 71a located towards a rear of the vehicle 100 (See Figure 4). The rear tubular members 71a are removably attached to a main roll over protection structure 70a. The rear tubular members 71a extend from a lower position of the main structure to an upper position of the roll over protection structure 70 at an acute angle to a vertical axis of the vehicle 100. In particular, the rear tubular members 71a are inclined towards a front of the vehicle 100. Put another way, the rear tubular members 71a extend from a lower portion of the vehicle 100 to an upper portion of the vehicle 100. The orientation of the rear tubular members 71a decreases the volume of the fuel tank enclosure from a maximum volume towards the lower portion of the vehicle 100 to a minimum volume towards the upper portion of the vehicle 100. To maximise the volume of the fuel tank 10 within the available space, the top panel 21 comprises a first top panel section 21a and a second top panel section 21b angled relative to each other at an obtuse angle. The first top panel section 21a and the second top panel section 21b are integrally formed, although it will be appreciated the first and second top panel sections 21a, 21 b may be separately formed and fastened together. This allows the fuel tank 10 to fit around the roll over protection structure 70, and in particular the inclined rear tubular members 71a of the roll over protection structure 70, with the rear tubular members 71a angled so as to extend across and generally parallel to the plane of the second top panel section 21b. Similarly, the stepped portions of the protective shell 12 accommodates the position of the rear tubular members 71a, whilst also maximising the usable space of the fuel tank enclosure. In other words, the rear tubular members 71a extend through the space defined by a respective stepped portion. The rear tubular members 71a are angled towards each other so as to form an inverted V configuration. In particular, the rear tubular member 71a have a maximum spacing therebetween towards a lower part of the vehicle 100 and a minimum spacing therebetween towards an upper part of the vehicle 100. This inverted V configuration provides several advantages over alterative configurations, such as an ‘X’ configuration. For instance, the inverted ‘V’ configuration provides improved access to the fuel interaction assembly 30 due to the increased spacing between the rear tubular members 71a at the level of the top panel 21 than would otherwise be achievable with an ‘X’ configuration. Similarly, the spacing between the rear tubular members 71a also provides improved visibility of a viewing window 29 in the protective shell 12 that allows access to the certification label and maintenance access for the fuel bladder 28 without disassembly of the protective shell 12. The rear tubular members 71 a are also absent a central junction between the rear tubular members 71a, which thereby makes manufacture and assembly / disassembly of the rear tubular members 71a easier. In turn, the ease of assembly / disassembly makes insertion of the fuel tank 10 within the fuel tank enclosure easier. The increased space towards a lower section of the vehicle 100 also provides additional stowage space. For instance, a spare tyre may be fitted rearwards of the fuel tank 10 and between the rear tubular members 71a. In particular, a tyre (not shown) may be oriented normal to the longitudinal axis of the vehicle 100 so as to be located between a lower portion of the rear tubular members 71a. The vehicle 100 includes a fuel tank mount frame 60 mounted on the protective shell 12. In Figure 4, the fuel tank mount frame 60 is mounted on the top panel 21. The fuel tank mount frame 60 includes a lateral brace member 61 that extends between the rear tubular members 71a. The lateral brace member 61 can act as a supporting member for the roll over protection structure 70. The fuel tank mount frame 60 defines an aperture providing access to the fuel interaction assembly 30. The fuel tank mount frame 60 extends between, and is fastened to, the roll over protection structure 70 and a bulkhead 80 of the vehicle 100. The bulkhead 80 separates a passenger compartment of the vehicle 100 from a rear cargo compartment of the vehicle 100, such as shown in Figure 4. The fuel tank 10 is located behind the bulkhead 80. In this way, the bulkhead 80 forms a protective barrier for vehicle occupants mt eh passenger compartment forward of the bulkhead 80. The protective shell 12 abuts the bulkhead 80. The protective shell 12 is fastened to the bulkhead 80. In particular, the rear panel 22 of the protective shell 12 is fastened to the bulkhead 80. The bulkhead 80 is arranged to accommodate the positioning of the roll over protection structure 70. In the present example, this has resulted in the bulkhead 80 including an inflected portion 81 (shown in Figure 6) that directs the bulkhead 80 out of the path of a pair of inclined tubular members 71b (See Figure 5). Accordingly, the protective shell 12 includes a corresponding inflected portion. In particular, the rear panel 22 is a two-part rear panel 22 comprising a first rear panel section 22a and a second rear panel section 22b fastened to the first rear panel section 22a at a convex edge 22c extending between the first and second side panels 25, 26. The assembly of the fuel tank 10 into the vehicle 100 will now be described. A vehicle 100 is provided comprising a main structure, a roll over protection structure 70, and a bulkhead 80. If the rear tubular members 71a are connected to the main roll over protection structure 70a then the rear tubular members 71a are disconnected. The fuel bladder 28 and each of the panels 21,22, 23, 24, 25, 26 of the protective shell 12 are inserted into the fuel tank enclosure. The panels 21, 22, 23, 24, 25, 26 are fastened together to form the protective shell 12 in which the fuel bladder 28 is held. The protective shell 12 is then fastened to the main structure of the vehicle and the bulkhead 80. The rear tubular members 71a are reconnected to the main roll over protection structure 70a to constrain the fuel tank 10 within the fuel tank enclosure defined by the roll over protection structure 70. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A fuel tank for a vehicle, comprising:a fuel bladder;a protective shell enveloping the fuel bladder, the protective shell formed of a top panel, a rear panel, a bottom panel, a front panel, a first side panel, and a second side panel fastened together; anda fuel interaction assembly of the fuel bladder extending through the top panel of the protective shell.

2. The fuel tank of claim 1, wherein the first side panel and the second side panel are spaced by a first width towards the rear panel and a second, smaller, width towards the front panel, with a stepped transition between the first and second widths defining a stepped portion of the fuel tank for accommodating an inclined portion of a roll over protection structure.

3. The fuel tank of claim 2, comprising a corner brace within the stepped portion of each of the first side panel and the second side panel.

4. The fuel tank of any preceding claim, wherein the top panel comprises a first top panel section and a second top panel section integrally formed and angled relative to each other at an obtuse angle.

5. The fuel tank of any preceding claim, wherein the rear panel is a two-part rear panel comprising a first rear panel section and a second rear panel section fastened to the first rear panel section at a convex edge extending between the first and second side panels.

6. The fuel tank of any preceding claim, comprising a strap extending laterally across the first side panel, front panel, and second side panel, and fastened at both ends to the rear panel.

7. A vehicle comprising the fuel tank of any preceding claim.

8. The vehicle of claim 7, wherein the bottom panel is fastened to a main structure of the vehicle and / or wherein the rear panel is fastened to a bulkhead of the vehicle.

9. The vehicle of claim 7 or 8, comprising a roll over protection structure having a plurality of tubular members defining a fuel tank enclosure in which the fuel tank is confined, wherein two rear tubular members of the plurality of tubular members are located towards a rear of the vehicle and extend from the main structure to an upper position of the roll over protection structure at an acute angle to a vertical axis of the vehicle.

10. The vehicle of claim 9 when dependent on claim 4, wherein the rear tubular members extend across and generally parallel to a plane of the second top panel section.

11. The vehicle of claim 9 or 10 when dependent on claim 2, wherein one of the rear tubular members extends through the first stepped portion of the fuel tank, and / or wherein the other of the rear tubular members extends through the second stepped portion of the fuel tank.

12. The vehicle of any preceding claim when dependent on claim 9, comprising a fuel tank mount frame mounted on the top panel, the fuel tank mount frame comprising a lateral brace member extending between the rear tubular members.

13. The vehicle of any preceding claim when dependent on claim 9, wherein the rear tubular members are angled towards each other so as to form an inverted V configuration.

14. The vehicle of any preceding claim when dependent on claim 9, wherein the rear tubular members are removably attached to a main roll over protection structure.

15. A method of assembling the vehicle of any one of claims 9 to 15, comprising:inserting the top, rear, bottom, front, first side, and second side panels into the fuel tank enclosure of the roll over protection structure;inserting the fuel bladder into the fuel tank enclosure;fastening the panels together within the fuel tank enclosure to form the protective shell enveloping the fuel bladder; and,fastening the protective shell to the main structure and / or bulkhead of the vehicle.

Images