METHOD FOR MANUFACTURING A FUEL TANK AND FUEL TANK

Abstract

The invention relates to a fuel tank comprising a tank body with an outer shell of a fibre-reinforced thermoplastic material comprising fibres embedded in a thermoplastic matrix, wherein an inner side of the outer shell is laminated with a multi-layered film of plastic, the outer shell being thicker than the multi-layer film of plastic and the multi-layer film of plastic comprising at least one barrier layer for hydrocarbons, wherein the fibres comprise at least one of glass fibres, carbon fibres and aramid fibres, wherein the fibre-reinforced material comprises at least one of woven or laid fibres embedded in the thermoplastic matrix

Claims

1-11. (canceled)

12. A fuel tank comprising: a tank body with an outer shell of a fibre-reinforced material comprising fibres embedded in a thermoplastic matrix, wherein an inner side of the outer shell is laminated with a multi-layered film of plastic, the outer shell being thicker than the multi-layered film of plastic and the multi-layered film of plastic comprising at least one barrier layer for hydrocarbons, wherein the fibres comprise at least one of glass fibres, carbon fibres and aramid fibres, wherein the fibre-reinforced material comprises at least one of woven or laid fibres embedded in the thermoplastic matrix.

13. The fuel tank according to claim 12, wherein: the multi-layered film of plastic has a maximum thickness of 1.25 mm.

14. The fuel tank according to claim 13, wherein: the multi-layered film of plastic comprises at least five layers with EVOH as the barrier layer.

15. The fuel tank according to claim 12, wherein: the ratio of the thickness of the outer shell to the multi-layered thickness of the film of plastic is between 2 and 1.2.

16. The fuel tank according to claim 14, wherein: the barrier layer is sandwiched between two adhesion promoter layers, and the barrier layer and the two adhesion promoter layers are sandwiched between two covering layers.

17. The fuel tank according to claim 16, wherein: each layer of the two adhesion promoter layers has a maximum thickness of 200 micrometers.

18. The fuel tank according to claim 12, wherein: the barrier layer has a thickness in a range of 50 to 250 micrometers.

19. The fuel tank according to claim 12, wherein: the outer shell comprises an upper shell and a lower shell, wherein each of the upper shell and the lower shell have an inner side, respectively, wherein the inner side of the upper shell and the inner side of the lower shell each provide a portion of the inner side of the outer shell; and wherein the inner side of the upper shell is laminated with the multi-layered film of plastic which provides a laminated upper shell; and wherein the inner side of the lower shell is laminated with the multi-layered film of plastic which provides a laminated lower shell.

20. The fuel tank according to claim 19, wherein: the laminated upper shell and the laminated lower shell are only laminated on the inner side, respectively, with the multi-layered film.

21. The fuel tank according to claim 19, wherein: the laminated upper shell and the laminated lower shell each have a peripheral flange.

22. The fuel tank according to claim 21, wherein: the peripheral flange of the laminated upper shell and the peripheral flange of the laminated lower shell are bonded to each other.

23. The fuel tank according to claim 22, wherein: the peripheral flange of the laminated upper shell and the peripheral flange of the laminated lower shell are bonded to each other such that the upper shell and the lower shell are bonded directly to each other.

24. The fuel tank according to claim 22, wherein: the peripheral flange of the laminated upper shell excludes the multi-layered film of plastic and the peripheral flange of the laminated lower shell excludes the multi-layered film of plastic such that a bond of the peripheral flange of the laminated upper shell and the peripheral flange of the laminated lower shell excludes the multi-layered film of plastic of the laminated upper shell and the multi-layered film of plastic of the laminated lower shell.

25. The fuel tank according to claim 21, wherein: the peripheral flange of the laminated upper shell or the laminated lower shell is folded over the peripheral flange of the other of the laminated upper shell and the laminated lower shell.

26. The fuel tank according to claim 21, wherein: the peripheral flanges of the laminated upper shell and the laminated lower shell form a peripheral edge-folded seam.

27. The fuel tank according to claim 21, wherein: an end face of the peripheral flange of the laminated upper shell and an end face of the peripheral flange of the laminated lower shell are disposed within a peripheral profile.

28. The fuel tank according to claim 27, wherein: the peripheral profile has a C-shaped profile or a U-shaped profile.

29. The fuel tank according to claim 12, further comprising: at least one insert disposed within the fuel tank, wherein the at least one insert comprises at least one of a valve, a venting line, a surge tank and a feel unit.

30. The fuel tank according to claim 29, wherein: the at least one insert is disposed on an insert carrier which welded or clamped to the outer shell of the tank.

31. The fuel tank according to claim 12, wherein: the outer shell is provided by a thermoformed sheet.

32. The fuel tank according to claim 12, wherein: the outer shell is provided by an organometallic sheet.

33. The fuel tank according to claim 12, wherein: the thermoplastic matrix comprises high density polyethylene.

Description

[0041] Reference is first made to FIG. 2 of the accompanying drawings.

[0042] FIG. 2 shows a view into an upper shell 1 of a fuel tank according to the invention. The fuel tank is joined together from the upper shell 1 and a lower shell 2, complementing the upper shell, to form an essentially closed hollow body. A full view of the fuel tank is not shown in the drawings.

[0043] Both the upper shell and the lower shell are provided with an encircling flange 8, at which the upper shell 1 and the lower shell 2 are joined to form the closed tank.

[0044] As already mentioned at the beginning, both the upper shell 1 and the lower shell 2 consist of a carrier material in the form of an organometallic sheet 3 and a laminate 4 laminated-on on one side, which in the present case is formed as a multi-layer film. The organometallic sheet 3 consists, for example, of a base material/matrix material of HDPE (High-Density Polyethylene) with fibres embedded in it in the form of carbon fibres, glass fibres or aramid fibres. The fibres are embedded in the matrix material in the form of a laid or woven structure. The organometallic sheet 3 may be additionally provided on the visible side/outer side with an HDPE covering layer, which ensures that the fibre reinforcement is completely covered.

[0045] The laminate 4 that is provided on the inside of the organometallic sheet 3 comprises two HDPE covering layers 5, two layers of adhesion promoter 6 and an EVOH layer 7 as a barrier layer.

[0046] A method for manufacturing the fuel tank according to the invention envisages the provision of a completely made-up and laminated semifinished product in the form illustrated in FIG. 1. The semifinished product is first subjected to a heat treatment and then shaped into shells in a thermoforming mould.

[0047] At the same time, the shells are formed with a preferably encircling flange 8.

[0048] In the region of this flange, the shells, i.e. the upper shell 1 and the lower shell 2, are preferably joined, i.e. connected to one another with a material bond, preferably welded to one another.

[0049] The different variants of the peripheral connection of the upper shell 1 and the lower shell 2 are illustrated in FIGS. 4 to 6.

[0050] FIGS. 4a and 4b show two successive method steps of the peripheral joining of the upper shell 1 and the lower shell 2, the procedure that is shown in FIGS. 4a and 4b being favourable if the flange 8 of the upper shell 1 and the lower shell 2 are respectively of different lengths.

[0051] In a first step, the just-formed upper shell 1 and lower shell 2 are placed one on top of the other, as represented in FIG. 4a. In this state, the upper shell 1 and the lower shell 2 may be still warm and plastic, so that subsequent welding can be performed by using the basic heat of the material.

[0052] In principle, however, the upper shell 1 and the lower shell 2 may also have been placed one on top of the other in the cold state. Then, for example, the flange 8 of both shells 1, 2 is heated by means of infrared radiation and softened until they plasticize.

[0053] In a next step, for example, the flange 8 of the lower shell 2 is folded over around the flange 8 of the upper shell 1 with a suitable tool (see FIG. 4b), so that the fuel tank is given a peripheral edge-formed seam 9, which in particular also forms a sealing labyrinth because of the multiple folding of the individual layers.

[0054] This type of connecting technique makes allowance in particular for the fact that the layer thickness of the laminate 4 is at most 1.25 nm, essentially only the covering layers 5 of the laminate 4 contributing to the welding.

[0055] An alternative embodiment of the joining operation is represented in FIG. 5.

[0056] The upper shell 1 and the lower shell 2 have a flange of the same dimensions; the flanges 8 are placed flush one on top of the other for the purpose of connecting the shells. Then, a U-shaped peripheral profile 10 of thermoplastic material, preferably of HDPE, is placed onto the tank seam, reaching around the flanges 8. The peripheral profile 10 is welded to the outer side of the organometallic sheets 3 while applying pressing pressure under heat.

[0057] Alternatively, adhesive bonding of the peripheral profile 10 may be provided, for example, with an adhesion promoter on the basis of LDPE.

[0058] The method according to the invention comprises the introduction of inserts 11 into the fuel tank before the joining of the upper shell 1 and the lower shell 2. For this purpose, the inserts, for example in the form of valves, nipples, filling-level sensors, surge tanks or the like, are premounted in a predetermined layout of the tank shell concerned on an insert carrier 12 in the form of a lattice support of thermoplastic material. The insert carrier 12 is then placed in the position shown in FIG. 2 in the upper shell 1 of the fuel tank.

[0059] The insert carrier 12 is formed, for example, as an injection-moulded plastic carrier, which is adapted to the contour of the upper shell 1 and has, for example, been placed into the upper shell 1. Alternatively, clamping or else welding is possible. The inserts 11, in the present case valves, are connected to one another by way of a relatively stiff venting line 13. One of the inserts 11 is provided with a connection nipple 14, which passes through a lead-through 15 of the upper shell 1.

[0060] The lead-through 15 is produced, for example, after completion of the upper shell 1 and before joining of the upper shell 1 to the lower shell 2, by cutting out a circle. Then, the insert carrier 12 is brought into the upper shell 1 in such a way that the connection nipple 14 passes through the lead-through 15. The connection nipple 14 lies, for example, with an encircling collar 16 against the laminate 4. The collar is provided with an annular groove 17, placed in which is an O-ring seal, which seals off the connection nipple 14 from the the lead-through 15.

[0061] The connection nipple 14 is also provided with a thread 19, which passes through the lead-through 15. On the outer side of the upper shell 1, the nipple is secured by a nut 20, which engages in the thread 19.

[0062] Alternatively, the connection nipple 15 may be latched by a fastening element provided on the outer side of the upper shell 1.

LIST OF REFERENCE SIGNS

[0063] 1 Upper shell [0064] 2 Lower shell [0065] 3 Organometallic sheet [0066] 4 Laminate [0067] 5 HDPE covering layer [0068] 6 Layer of adhesion promoter [0069] 7 EVOH layer [0070] 8 Flange [0071] 9 Sealing labyrinth [0072] 10 Peripheral profile [0073] 11 Inserts [0074] 12 Insert carrier [0075] 13 Venting line [0076] 14 Connection nipple [0077] 15 Lead-through [0078] 16 Collar [0079] 17 Annular groove [0080] 18 O-ring seal [0081] 19 Thread [0082] 20 Nut