Patent Description:
The use of hydrogen as a fuel for automobiles and other transportation vehicles is expected to increase in popularity in the near future. Onboard storage of hydrogen presents a number of challenges. Because of its low energy to volume ratio, hydrogen gas is often stored in a tank and kept at a high pressure, e.g., <NUM>,<NUM> - <NUM>,<NUM> psi (<NUM> - <NUM> bar). These challenges may be particularly marked in the storage of hydrogen in light vehicles, such as automobiles, limiting the potential size and weight of the storage tank. In particular, a hydrogen storage tank may expand while being filled and contract while hydrogen is depleted through consumption.

<CIT> describes a mounting system for a fuel tank. The fuel tank has a first boss at its first end and a second boss at its second end. A fixed bearing block assembly that includes two rigid block members supports the fuel tank at the second boss. Another bearing block assembly that includes two block portions is configured to permit some movement between its inner periphery and the first boss of the fuel tank.

According to a first aspect of the invention, there is provided a mounting system for a fuel tank as defined in claim <NUM>. For example, the first mount may be configured to mount a first elongated neck portion of a dual port fuel tank, directly or indirectly, to a vehicle chassis, and the second mount may be configured to slidably mount a second elongated neck portion of the dual port fuel tank to the vehicle chassis.

Because the second mount allows movement of at least part of the second portion of the fuel tank, stresses on fuel pipes connected to the fuel tank, the first and second mounts, and other vehicle components may be reduced. This can, in turn, improve durability of the fuel system and vehicle and/or allow for reduced manufacturing tolerances.

The first mount comprises a body portion and a cap portion that, when attached together, form an aperture to receive the first portion of the fuel tank, connected together by at least one fastener. The fastener is configured to attach the body portion to the cap portion with a clearance between the body portion and the cap portion. Such a clearance may reduce shear forces exerted on the first mount that would otherwise be experienced at an interface between the body portion and the cap portion, for example, in response to expansion or contraction of the fuel tank or shocks arising from sudden changes in motion of a vehicle.

A sleeve is provided around at least part of the fastener to increase a region of the first mount over which such shear forces are distributed. For example, where the body portion and the cap portion of the first mount are attached together using one or more bolts, at least a part of a shaft of each bolt may be covered by a sleeve, e.g., a hollow dowel, that extends through at least a part of the body portion and at least a part of the cap portion.

The second mount provides an aperture to receive the second portion of the fuel tank, configured to allow sliding motion of the at least part of the second portion of the fuel tank through the aperture. An insert surrounds an inner surface of the aperture, formed of a material that provides surface along which the second portion can slide with reduced friction. The provision of a relative low friction surface improves the effectiveness with which the sliding motion and, therefore, the expansion and contraction of the fuel tank, is accommodated, as well as reducing wear on the second portion.

The insert includes a circumferential groove configured to receive the inner surface of the aperture. By locating the inner surface of the aperture within such a groove, movement of the insert along a direction of the sliding motion, relative to the aperture, can be reduced or avoided altogether.

The second mount comprises a body portion and a cap portion that, when attached together, are arranged to receive the second portion of the fuel tank, and at least one fastener that attaches the body portion of the second mount to the cap portion of the second mount. For example, the body portion and the cap portion of the second mount may be attached to one another using one or more bolts. Such fasteners can assist in reducing forces arising from sudden changes in the motion of the vehicle, improving the durability of the mounting system, fuel system and vehicle.

According to another aspect of the invention, there is provided a hydrogen fuel system comprising a fuel tank configured to store gaseous fuel, and a mounting system according to the first aspect. In such a system, the fuel tank may be a dual port fuel tank with first and second elongated neck portions, where the first mount receives the first elongated neck portion and the second mount receives the second elongated neck portion.

According to yet another aspect of the invention, there is provided a vehicle including the above mounting system and/or hydrogen fuel system.

According to a further aspect of the invention, there is provided a method of assembling a fuel system as defined in claim <NUM>.

Examples will now be described by way of example only, with reference to the Figures, in which:.

With reference to <FIG>, a fuel system <NUM> is mounted in a cradle <NUM> and attached to a vehicle chassis <NUM>. In this particular example, the fuel system <NUM> includes four hydrogen fuel tanks 106a-d arranged to supply hydrogen gas to a fuel cell <NUM>. The fuel system <NUM> also includes batteries <NUM>, <NUM>, inverter <NUM>, distribution unit <NUM>.

The fuel tanks 106a-d are attached to the cradle <NUM> by respective first and second mounts. For example, fuel tank 106a is attached by first mount 118a and second mount 120a. <FIG> is a view of the cradle <NUM> with the fuel tanks 106a-106d removed, allowing the first mounts 118a-d for respective fuel tanks 106a-d and the second mount 120c for fuel tank 106c to be shown more clearly.

<FIG> depict one of the fuel tanks 106a of the fuel system <NUM>. In this example, the fuel tank 106a is a dual port fuel tank including first and second elongated neck portions <NUM>, <NUM>. The first elongated neck portion <NUM> is attached to the chassis <NUM> via the cradle <NUM> and the first mount 118a, while the second elongated neck portion <NUM> is attached to the chassis <NUM> via the cradle <NUM> and the second mount 120a.

The first and second mounts 118a, 120a each include an aperture <NUM>, <NUM> configured to receive respective ones of the neck portions <NUM>, <NUM> of the fuel tank 106a. The first mount 118a is configured to hold the first elongated neck portion <NUM> in a fixed position, while the second mount 120a is configured to allow sliding motion of the second elongated neck portion <NUM> through the aperture <NUM>, along the x direction indicated in <FIG>.

As discussed above, the hydrogen fuel tank 106a may expand while being filled. An expansion of the fuel tank 106a will cause sliding motion of the second neck portion <NUM> through the aperture <NUM> of the second mount 120a along the negative x direction, while the first neck portion <NUM> remains fixed in position by the first mount 118a. Such sliding motion of part of the fuel tank 106a allows the expansion of the fuel tank 106a to be accommodated within the fuel system <NUM> with reduced stress on the components of the fuel system <NUM>, when compared with systems using only fixed mountings.

In a similar manner, contraction of the fuel tank 106a as the amount of hydrogen stored in the fuel tank 106a decreases causes sliding motion of the second neck portion <NUM> through the aperture <NUM> in the positive x direction, allowing the contraction to be accommodated with limited stress on the components of the fuel system <NUM>.

<FIG> depicts an example first mount 118a for use in the fuel system <NUM> of <FIG>, where a portion of the first mount 118a on the left of <FIG> is shown in section. In this particular example, the first mount 118a includes a body portion <NUM> and a cap portion <NUM>, which form the aperture <NUM> when attached together by at least one fastener. In the example shown in <FIG>, the body portion <NUM> and cap portion <NUM> are attached together by one or more bolts 134a that extend through at least part of the body portion <NUM> and at least part of the cap portion <NUM>.

The fastener is configured to provide a clearance <NUM> between adjacent surfaces of the body portion <NUM> and cap portion <NUM> when attached together. Such a clearance may reduce the effect of shear forces that would be present at the interface between the body portion <NUM> and cap portion <NUM> if their adjacent surfaces were in contact, or close contact, e.g., when clamping one end of the fuel tank to the vehicle.

A sleeve <NUM> is provided around each fastener and extends into at least a part of the body portion <NUM> and at least a part of the cap portion <NUM>. In this particular example, a sleeve <NUM>, such as a hollow dowel, is provided around a part of a shaft <NUM> of each bolt 134a. Such a sleeve <NUM> can distribute any shear forces experienced by the bolt 134a along its shaft <NUM>, e.g., due to loading of the cap portion <NUM> relative to the body portion <NUM>.

In this manner, the clearance <NUM> and the sleeve <NUM> can limit localisation of stresses on at least one of the fastener, the body portion <NUM> and cap portion <NUM>, improving the durability of the first mount 118a.

As shown in <FIG>, the first mount 118a may be attached to the cradle <NUM> using bolts 142a, 142b or other fasteners. In other examples, the first mount 118a may be attached directly to the chassis <NUM> and/or to another part of a vehicle.

<FIG> depicts an example second mount 120a for use in the fuel system <NUM> of <FIG>, where a portion of the second mount 120a on the right of <FIG> is shown in section. In this example, the second mount 120a includes a body portion <NUM> and a cap portion <NUM>, which form the aperture <NUM> when attached together. In the example shown in <FIG>, the body portion <NUM> and cap portion <NUM> are attached together by at least one fastener. In this particular example, the at least one fastener includes a bolt 148a that extends through at least part of the body portion <NUM> and at least part of the cap portion <NUM> of the second mount 120a, to clamp the body portion <NUM> and the cap portion <NUM> together.

The second mount 120a may be attached to the cradle <NUM>, the chassis <NUM>, or another part of a vehicle, using fasteners such as bolts 150a, 150b.

An insert <NUM> is provided that surrounds an inner surface of the aperture <NUM>. The insert <NUM> may be formed of a material that reduces friction when the second neck portion <NUM> of the fuel tank 106a slides through the aperture <NUM>. In this particular example, the insert <NUM> is formed of a plastics material.

As shown in <FIG> and <FIG>, the insert <NUM> includes a circumferential groove <NUM>, configured to receive the inner surface of the aperture <NUM>. Because the inner surface of the aperture <NUM> is located within the groove <NUM>, contact between the inner surfaces of the groove <NUM> and sides of the body portion <NUM> and the cap portion <NUM> resists motion of the insert <NUM> along the x direction. In this manner, the insert <NUM> is held in position when the second neck portion <NUM> is sliding through the aperture <NUM>. The body portion <NUM> and the cap portion may be sized to ensure that tightening of a fastener, e.g., bolt 148a, does not substantially deform, e.g., by more than <NUM> microns or <NUM> microns, an inner opening of the insert <NUM> upon clamping the body portion <NUM> and the cap portion <NUM> together. In this manner, excessive clamping force is not applied to a portion of the fuel tank that is secured in the second mount 120a.

<FIG> shows an example of a vehicle <NUM> in which the fuel system may be installed. The vehicle <NUM> includes the fuel system <NUM> described above with reference to <FIG>, located in the cradle <NUM> and attached to the underside of the chassis <NUM>. As discussed above, in other examples, the fuel system <NUM> may be attached, directly or indirectly, to the chassis <NUM> or to another part of the vehicle.

Although the vehicle <NUM> shown in <FIG> is an automobile, the mounting system described above may be used to mount fuel tanks in other vehicles, including vans, trucks, coaches, buses, trucks, lorries, or any other appropriate vehicle. In some examples the mounting system described above may be used to mount fuel tanks in other applications, such as power generators, etc..

Claim 1:
A mounting system for a fuel tank, comprising:
a first mount (118a) configured to attach a first portion of the fuel tank (106a) in a fixed position on a vehicle, the first mount (118a) comprising:
a body portion (<NUM>) and a cap portion (<NUM>) that, when attached, form an aperture (<NUM>) to receive the first portion of the fuel tank;
at least one fastener (134a) for attaching the body portion to the cap portion, wherein a clearance (<NUM>) is maintained between the body portion and the cap portion in an assembled configuration; and
a sleeve (<NUM>) located around at least part of the fastener; and a second mount (120a) configured to attach a second portion of the fuel tank (106a) on the vehicle and to allow movement of at least part of the second portion relative to the vehicle, the second mount (120a) comprising:
a body portion (<NUM>) and a cap portion (<NUM>) that, when attached, form an aperture (<NUM>) to receive the second portion of the fuel tank;
an insert (<NUM>) that surrounds an inner surface of the aperture upon clamping the body portion and the cap portion together, the insert comprising a circumferential groove (<NUM>) configured to receive the inner surface of the aperture; and
at least one fastener (148a) for clamping together the body portion to the cap portion.