WO2014149060A1

WO2014149060A1 - High pressure fuel tank

Info

Publication number: WO2014149060A1
Application number: PCT/US2013/033551
Authority: WO
Inventors: Mark Lill
Original assignee: International Truck Intellectual Property Company, Llc
Priority date: 2013-03-22
Filing date: 2013-03-22
Publication date: 2014-09-25

Abstract

A jacket has an expandable material shaped to define an inner volume that substantially encloses a high pressure fuel tank. An input disposed on or in the jacket is in fluid communication with the inner volume. The input is configured to fluidly couple with an over pressure output device of the high pressure fuel tank.

Description

HIGH PRESSURE FUEL TANK

BACKGROUND

[0001] Embodiments described herein relate generally to fuel storage for vehicles.

[0002] Fuels that are in a gaseous state at atmospheric pressure, such as compressed natural gas (CNG), liquefied natural gas (LNG), hydrogen, propane, and others, are increasingly used for powering vehicles. Such fuels typically are stored, for example as a liquid, in high pressure fuel tanks; i.e., fuel tanks capable of withstanding high pressures. When internal pressure of a high pressure fuel tank ("tank") becomes too high, an over pressure output device provided on the tank releases the high pressure fuel into the atmosphere.

SUMMARY

[0003] A jacket has an expandable material shaped to define an inner volume that substantially encloses a high pressure fuel tank. An input disposed on or in the jacket is in fluid communication with the inner volume. The input is configured to fluidly couple with an over pressure output device of the high pressure fuel tank.

[0004] An apparatus for storing a fuel comprises the above tank jacket and a high pressure fuel tank configured to store the fuel. The tank has a tank skin for storing the fuel under high pressure, a selectably releasable opening for selectively releasing the fuel, and the over pressure output device. The tank skin is disposed within the inner volume of the jacket, and the input is fluidly coupled to the over pressure output device. [0005] A jacket is provided for a high pressure fuel tank. The high pressure fuel tank comprises a tank skin for storing a fuel under high pressure, an opening for selectively releasing the fuel, and an over pressure output device. The jacket has expandable means for enclosing and thermally insulating the tank skin within an inner volume, and means for fluidly coupling the over pressure output device to the inner volume.

[0006] For a high pressure fuel tank comprising a tank skin containing fuel, an opening for selectively releasing the fuel, and an over pressure output device, a method of containing a fuel that is released from the over pressure output device is provided. The released fuel is directed into an inner volume of a jacket. The jacket comprises a thermally insulating and expandable material defining an inner volume that substantially encloses the tank skin. The released fuel is stored within the inner volume and outside the tank skin. The released fuel has a lower temperature than the fuel contained within the tank skin due to the pressure change. The storing causes the jacket to expand.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of a high pressure fuel tank mounted to a vehicle, without a jacket.

[0008] FIG. 2 is a sectional view of the high pressure fuel tank of FIG. 1.

[0009] FIG. 3 is a perspective view of a jacket disposed around the high pressure fuel tank of FIG. 1, with a valve assembly removed for clarity. [0010] FIG. 4 is a perspective view of the jacket of FIG. 3 disposed around the high pressure fuel tank as mounted in FIG. 1, in which the jacket is not inflated.

[0011] FIG. 5 is a sectional view of the jacket and high pressure fuel tank of

FIG. 4.

[0012] FIG. 6 is a perspective view of the jacket and high pressure fuel tank similar to FIG. 4, in which the jacket is inflated.

[0013] FIG. 7 is a sectional view of the jacket and high pressure fuel tank of

FIG. 6.

DETAILED DESCRIPTION

[0014] Referring to FIGs. 1-2, a high pressure fuel tank (tank) is generally indicated at 10. The tank 10 includes a tank skin 12 configured to store a fuel at a high pressure (e.g., gas compressed to 3000-3600 psi for on-board storage, or chilled to minus 260 °F to become a cryogenic liquid). While the example tank skin 12 is generally cylindrical in shape, other shapes for the tank skin are possible. Example materials for the tank skin 12 include steel, aluminum, plastic, polymer, and composite material, and can include additional material for reinforcement. To retain the tank 10 and mount the tank, for instance horizontally to a chassis 14 of a vehicle, a holding assembly, generally indicated at 16, includes a pair of clamps 18. Each clamp 18 is partially disposed within a girdle 20 that allows the force of the clamp to be distributed over the tank. An outer surface 22 is defined by the outside of the tank skin 12. The girdle 20 can be disposed around the outer surface 22. Each of the clamps 18 is removably mounted to a respective U-beam 24. The U-beams 24 are in turn mounted to the chassis 14 using suitable fasteners. The chassis 14 can vary in configuration depending on the vehicle. If the tank 10 is mounted vertically, the clamps 18 shown can be omitted.

[0015] A lower frame 30 is mounted to the U-beams 24, though the lower frame can be mounted at other locations. The lower frame 30 includes supports 36 for mounting a step (not shown) for assisting entry into a vehicle. If the tank 10 is mounted vertically, the configuration of the lower frame 30 can vary, or the lower frame can be omitted (for instance, the tank 10 can be disposed to rest on outer ridges or lips (not shown)).

[0016] The tank 10 includes a valve assembly, generally referred to at 40, that is disposed at a tank ring 42 at an end of the tank. The valve assembly 40 is coupled to the tank skin 12 via inner threads 44 disposed within the tank ring 42. The valve assembly 40 includes a valve control 45 and a nozzle 46 for outputting fuel from the valve assembly to, for instance, a vehicle engine. The valve assembly 40 shown is an example, and those of ordinary skill in the art will appreciate that other configurations for the valve assembly 40 are possible.

[0017] Certain events can cause the internal pressure of the tank 10, particularly the internal pressure of the tank skin 12, to increase. As one example, the internal pressure of the tank 10 increases if the tank storing fuel becomes too warm. An over pressure output device 50 is provided, e.g., as part of the valve assembly 40 or elsewhere, to release fuel if the internal pressure of the tank 10 gets too high. An example over pressure output device 50 is a valve for ASME Code Constructed Vessels. Other example over pressure output devices include a diaphragm or a blow out valve.

[0018] If the over pressure output device 50 is open to the atmosphere, the escaped fuel is dissipated into the surroundings. FIGs. 3-7 show a jacket, generally indicated at 60, which can be configured and disposed for capturing, at least temporarily, this fuel. While the example jacket 60 is generally cylindrically shaped to fit a generally cylindrical tank such as tank 10, it will be appreciated that the jacket could be shaped or configured in other ways to fit other tank configurations.

[0019] The jacket 60 includes an expandable material 62 having an interior surface 63 that at least partially defines an inner volume 64. "Expandable" refers to being capable of expanding, e.g., by unfolding of excess material, deforming to stretch, etc. to expand the inner volume 64.

[0020] This inner volume 64 substantially encloses the tank 10, for instance substantially encloses the tank skin 12, when the tank 10 is inserted into the jacket 60. A fluid capture volume 66 (e.g., see FIGs. 5 and 7), which is a portion of the inner volume 64, can be defined by a space that is disposed between the interior surface 63 of the expandable material 62 and the outer surface 22 of the tank skin 12. As a nonlimiting example, the capture volume 66 can be about 3 cubic feet when expanded. If the expandable material 62 is shaped to closely fit the shape of the tank skin 12 and thus wrap around the skin closely, the combined jacket 60 and tank 10 can be substantially flush with one another, and thus take up a relatively small amount of overall volume. Further, for a horizontally mounted tank 10, if the expandable material 62 is sufficiently thin, the additional size provided by the jacket 60 can be under the clamping variance for the tank provided by the clamps 18, and thus be disposed between the outer surface 22 of the tank skin 12 and the clamps 18, as shown in FIGs. 4-7. However, the expandable material 62 can be of larger thicknesses and fit over the tank 10 more loosely as well. Modifications for mounting the combined tank 10 and jacket 60 will be appreciated by those of ordinary skill in the art.

[0021] The jacket 60 is configured to capture and at least temporarily store escaped fuel from the over pressure output device 50 within the jacket's inner volume 64. The expandable material 62 can be made of a thermally insulating material, though low thermally insulating materials are also possible. Low thermally insulating materials will still provide at least some thermal insulation for the tank 10. The expandable material 62 can be selectively semipermeable to high pressure fluid fuel to permit fuel to escape slowly. Alternatively, the expandable material 62 can be selected to be less permeable and thus retain fuel, for instance for later removal. Example materials for the expandable material 62 include polyethylene, such as flashspun polyethylene fibers and/or polystyrene, such as close-celled polystyrene insulation. In an example embodiment, the expandable material includes a strong outer sheath, for instance manufactured from TYVEK®, disposed around an inner insulating layer of closed cell foam. The thickness of the inner insulating layer can be increased or decreased to increase/decrease the thermal insulation value. Other, nonlimiting example materials include carbon (e.g., reinforced carbon-carbon), material from FIBs (flexible insulation blankets), etc.

[0022] The jacket 60 includes an input, generally referred to at 70, on or in the expandable material 62 that is configured to be fluidly coupled with the over pressure output device 50. The input 70 can include, for instance, an opening 72, which is in fluid communication with the inner volume 64. A grommet 74 or other suitable member can be disposed about the opening 70. A fluid coupling 76, such as but not limited to a hose or other fluid conduit, can be coupled to the over pressure output device 50 via any suitable manner, for introducing fuel to the inner volume 64. Further, a seal 78, for instance an elastic seal such as but not limited to an elastic band, is disposed to at least partially cover the opening 72 to seal the opening, or at least partially cover another opening on the expandable material 62 that is in fluid communication with the inner volume 64, to seal this alternative opening. For instance, the seal 78 can be disposed about an interface between the fluid coupling 76 and the opening 72. The seal 78 can help seal the overall inner volume 64 around the tank 10. In an example embodiment, if the pressure inside the inner volume 64 becomes excessive, the seal 78 can expand to release stored fuel. In another embodiment, the seal 78 includes a material that is selected and configured to rupture if the pressure inside the inner volume 64 becomes excessive. The seal 78 in various configurations can provide an automatic release device for venting fuel.

[0023] In another example embodiment, the over pressure output device can be disposed closer to the tank ring 42 of the tank 10, and an input to the jacket can be provided by an opening 80 in the expandable material 62 through which the valve assembly 40 extends. This opening 80 can extend over the over pressure output device so that the over pressure output device is fluidly coupled to the inner volume 64. A neck seal (not shown), such as but not limited to an elastic band, can seal the opening 80 around the tank ring 42, such that escaped fuel enters the inner volume 64. If the inner pressure becomes excessive, the seal can expand to release excess fuel.

[0024] Referring now to FIGs. 4-5, to install the jacket 60 around the tank 10, the tank is provided. If the tank 10 is mounted via the holding assembly 16 or other mounting device or configuration, it can be removed before installing the jacket 60. For other mounting configurations, such as certain vertical mountings, this can be omitted. The tank 10 slides into the jacket 60 so that the tank skin 12 is disposed within the inner volume 64. The over pressure output device 50 is fluidly coupled, e.g., connected, to the input 70, e.g. via the fluid coupling 76. The seal 78 can be provided at or near the opening 72. In an example embodiment, the combined jacket 60 and tank 10 are mounted within the holding assembly 16. For other configurations for the tank 10, the mounting can be varied as will be appreciated by those of ordinary skill in the art.

[0025] FIGs. 4-5 show the combined tank 10 and jacket 60 in a state before fuel has escaped at high pressure via the over pressure output device 50. The expandable material 62 is wrapped closely around (e.g., flush against) the tank skin 12, and thus the fluid capture volume 66 between the interior surface 63 of the jacket 60 and the outer surface 22 of the tank skin 12 is relatively small.

[0026] FIGs. 6-7 show the combined tank 10 and jacket 60 in a state after fuel under high pressure has escaped via the over pressure output device 50. The escaped fuel is directed to the inner volume 64 of the tank cover via the input 80 fluidly coupled to the over pressure output device 50. Because the fuel does not return to the interior of the tank skin 12, it flows throughout the fluid capture volume 66, which volume is increased due to the expansion of the expandable material 62. In the example horizontal mounting of FIGs. 6-7, the fixed clamps 18 partially restrict the expansion of portions of the expandable material 62, causing the fluid capture volume 66 to be generally divided into a plurality of pockets 90. These pockets 90 can be in fluid communication with other pockets in the fluid capture volume 66 by, for instance, providing pass through channels (not shown) such as but not limited to ducts in the mounting loop. For example, ducts can be disposed on the fixed clamps 18 between the frame of the vehicle and the tank 10. Pass through channels allow the flow of fuel throughout the capture volume 66. The shape and size of the pass through channels can vary depending on the configuration of the tank 10, the mounting hardware, or both. For other mounting arrangements, including horizontal arrangements without the clamps 18 or for vertical mounting arrangements, the resulting fluid capture volume 66 can take other shapes. The expansion of the expandable material 62, which can appear similar to a low pressure balloon, can provide a visual indicator that fuel has escaped the tank 10, and thus also provides an indicator of high pressure in the tank.

[0027] When fuel escapes the tank 10 at high pressure, the maximum change of temperature due to the escaping fuel is provided at the over pressure output device 50. This cooler fuel is distributed throughout the fluid capture volume 66, and held against the outer surface 22 of the tank skin 12 by the interior surface 63 of the jacket 60. This helps to cool the tank 10 (enhanced if the expandable material 62 is made of a thermally insulating material) and thus help decrease the amount of fuel lost. If the pressure within the inner volume 64, including within the fluid capture volume 66, exceeds a predetermined pressure, the automatic release device, such as the seal 78, can operate (e.g., expand due to the higher internal pressure) to allow fuel to be released.

[0028] The captured fuel can be recovered by, for instance, releasing the seal 78 to empty the fuel into a suitable storage container. The jacket 60 then can retract to again be flush against the tank skin 12. Before removal (or installation) of the jacket 60, the captured fuel can be removed. With an example jacket 60, if no fuel is captured within the inner volume 64, the jacket can be slid on and off easily. [0029] An example jacket 60 can be replaceable. Depending on the configuration, the jacket 60 can be used for various tanks, including tanks for new or preexisting high pressure fuel powered vehicles. Fuel can be captured before it is released into the atmosphere. Capturing cooler fuel can reduce fuel loss. Fuel costs can be reduced. The expansion of the expandable material 62 can provide a visual indicator that can be used for tank 10 and/or vehicle diagnosis.

Claims

What is claimed is:

1) A jacket for a high pressure fuel tank comprising: an expandable material shaped to define an inner volume that substantially encloses the high pressure fuel tank; and an input disposed on or in the jacket, the input being in fluid communication with the inner volume; wherein the input is configured to fluidly couple with an over pressure output device of the high pressure fuel tank.

2) The jacket of claim 1, wherein the expandable material comprises a thermally insulating material.

3) The jacket of claim 1, wherein the expandable material is semi permeable.

4) The jacket of claim 1, further comprising: an automatic release device in fluid communication with the inner volume; wherein the automatic release device is configured to release fuel stored within the inner volume. 5) The jacket of claim 1, wherein the automatic release device comprises: an opening in or on the expandable material that is in fluid communication with the inner volume; a seal disposed at least partially over the opening, the seal being configured to be opened to selectively release stored high pressure fuel within the inner volume.

6) The jacket of claim 5, wherein the input comprises: the opening; and a fluid coupling that is coupled to the opening and to the over pressure output device; wherein the seal is disposed at an interface between the opening and the fluid coupling.

7) The jacket of claim 1, wherein the expandable material comprises an outer sheath disposed around an inner insulating layer.

8) The jacket of claim 1, wherein the expandable material comprises an insulating material taken from the group consisting of polyethylene, polystyrene, and carbon.

An apparatus for storing a fuel, the apparatus comprising: a high pressure fuel tank configured to store the fuel, the high pressure fuel tank comprising a skin for storing the fuel, a selectably releasable opening for selectively releasing the fuel, and an over pressure output device; and

the jacket of claim 1; wherein the skin is disposed within the inner volume of the jacket; and wherein the input is fluidly coupled to the over pressure output device.

10) The apparatus of claim 9, wherein the fuel comprises a fuel taken from the group consisting of compressed natural gas, liquefied natural gas, hydrogen, and propane.

11) The apparatus of claim 9, further comprising: a holding assembly disposed and configured for retaining the high pressure fuel tank and the jacket.

12) For a high pressure fuel tank comprising a skin for storing a fuel under high pressure, a selectively releasable opening for selectively releasing the fuel, and an over pressure output device, a jacket comprising: expandable means for enclosing and thermally insulating the skin within an inner volume; and means for fluidly coupling the over pressure output device to the inner volume. 13) The jacket of claim 12, further comprising: means for releasing high pressure fuel within the inner volume; wherein the means for releasing are in fluid communication with the inner volume.

14) For a high pressure fuel tank comprising a skin containing fuel, a selectively releasable opening for selectively releasing the fuel, and an over pressure output device, a method of containing fuel that is released from the over pressure output device, the method comprising: directing the released fuel into an inner volume of a jacket, wherein the jacket comprises a thermally insulating and expandable material defining an inner volume that substantially encloses the skin; and storing the released fuel within the inner volume and outside the skin; wherein the released fuel has a lower temperature than the gaseous fluid fuel contained in the skin due to a pressure change in the release fuel; and wherein the storing causes the jacket to expand.

15) The method of claim 15, further comprising: releasing the stored fuel by an automatic release device.