Fuel tank for gas-powered vehicle

Abstract

The invention relates to a fuel tank (1) for storing gas and for installation in a gas-powered vehicle, in particular a utility vehicle (20), wherein the fuel tank (1) has an elongate shape which is cylindrical in the central region and is closed by curved pole caps at both ends, and a reinforcing layer made of fibre-reinforced plastic, and a metal connection piece on each of the pole caps, known as a boss, and wherein the fuel tank (1) has at least two fastening devices (2, 3) which surround the cylindrical central part of the fuel tank (1) with the aid of tensioning straps and are provided for fastening the fuel tank (1) to a support structure (10), wherein the the cylindrical central region of the fuel tank (1) has on the outer side thereof a ridge (6, 6', 6''), which is arranged directly adjacent to one of the fastening devices (2, 3) and abuts against this such that and is designed such that the fuel tank (1) is unable to slip through the tensioning strap(s) of this one fastening device (2, 3) at least in one direction.

Description

[0001] Fuel tank for gas-powered vehicle

[0002] The invention relates to a fuel tank for storing gas for installation in a gas-powered vehicle, in particular a commercial vehicle, wherein the fuel tank has an elongated shape which is cylindrical in the central region and closed at both ends with curved pole caps, and has a reinforcing layer made of fiber-reinforced plastic, as well as a metallic connecting piece, a so-called boss, on each of the pole caps, and wherein the fuel tank has at least two fastening devices which enclose the fuel tank by means of tensioning straps and are provided for fastening the fuel tank to a supporting structure.

[0003] The support structure serves to mount the fuel tank to the vehicle frame. If necessary, multiple fuel tanks can be attached to a support structure and installed together as a tank module in the vehicle.

[0004] Gas-powered vehicles, for example, are powered by a gas engine or a fuel cell with an electric motor. In order to store sufficient fuel, the gas, which can be hydrogen, among other things, is stored under high pressure in the tank. Pressures of over 200 bar are typical for such pressure tanks, often up to 700 bar or 875 bar. This means that the fuel tank must not only be gas-tight under this pressure, but also require a high level of mechanical stability. In addition, the fuel tank must be large enough for a commercial vehicle, which is why such fuel tanks are often more than 2 m long. Securely attaching such long fuel tanks to the vehicle is a challenging task, as the fuel tanks are very heavy and expand lengthwise when exposed to corresponding internal pressure.

[0005] Fuel tanks for gas-powered vehicles are known in the prior art. These pressure tanks have a wall that includes an internal liner, for example, made of thermoplastic, for sealing, and a reinforcing layer made of fiber-reinforced plastic to provide mechanical stability. The reinforcing layer is preferably wound and designed as a CFRP layer. CFRP stands for carbon fiber reinforced plastic.

[0006] The boss has a through-hole and a connection thread. At least one of the two bosses is connected to a tank fitting when installed in the vehicle, allowing the pressure tank to be filled or gas to be drawn off in a controlled manner. On the other boss, the through-hole is sealed with a cap or a safety valve is provided.

[0007] Fuel tanks for gas-powered vehicles are known in the prior art. Among other things, DE 202007015487 U1 describes a tank module. The two fuel tanks are clamped to a support structure at each end of the cylindrical center section using a tensioning strap as a fastening device. Each tensioning strap wraps around two fuel tanks. The tank module is attached to the vehicle frame via the support structure. A tank fitting is provided at one end of the fuel tank, through which the tanks are filled and emptied and contains the necessary safety devices. A base is also provided, which is adapted to the cross-sectional shape of the fuel tank and against which the fuel tank is pressed. However, excessive clamping can cause damage to the surface of the reinforcement layer.

[0008] Fuel tanks that are mounted vertically in the vehicle are also known, as shown, for example, in document US 2019 / 0255941 A1. This offers the advantage that the fuel tanks can be accommodated behind the driver's cab, particularly in commercial vehicles, in a space-saving manner. In the design shown there, the fuel tanks are attached with a fastening device that engages the boss. However, such a mounting has the disadvantages of being more complex and very rigid. This means that vibrations and shocks cannot be effectively compensated for.

[0009] The object of the invention is to provide a fuel tank with a fastening device which is better suited for installation in the vehicle by ensuring that the fuel tank is securely and reliably fastened.

[0010] The object is achieved by a fuel tank according to claim 1. Further advantageous features are mentioned in the respective dependent claims.

[0011] According to the invention, the fuel tank is characterized in that it has at least one bead on the outside in the cylindrical central region, which is arranged directly next to one of the fastening devices and rests against it, and is designed such that the fuel tank cannot slip through the tensioning straps of this fastening device in at least one direction. This direction is meant to be parallel to the tank's longitudinal direction.

[0012] The particular advantage of the inventive design is that it provides a secure and vibration-damping fastening without the need to overtighten the tensioning straps. The bead now prevents slippage. Damage to the reinforcement layer caused by overtightening the tensioning straps is thus prevented.

[0013] As a further advantage, the fuel tank offers clear positioning for the installation of the fastening devices.

[0014] Additionally, improved vertical mounting of the fuel tank in the vehicle is possible. Especially with vertical mounting, just one bead is sufficient.

[0015] The tensioning straps of the fastening device are designed in particular as simple clamps or as so-called articulated strap clamps.

[0016] A bead is defined as a local elevation with a larger circumference than the diameter of the cylindrical center section of the fuel tank. This bead design requires less material than if, for example, the entire cylindrical center section had a larger diameter and the tensioning straps were then inserted into a recessed groove to prevent slippage. A groove in the reinforcement layer can also reduce the strength of the fuel tank due to stress concentrations.

[0017] The fact that the bead rests against the fastening device means that no undesired, safety-relevant movement of the fuel tank is possible due to the tensioning straps of the fastening device in a direction parallel to the tank's longitudinal direction t. This prevents displacement of the fuel tank during operation due to acceleration forces, such as those that occur during braking, vibrations or longitudinal expansion due to changes in the internal pressure, at least on one fastening device. In particular, with horizontally mounted side tanks, high forces occur in the tank's longitudinal direction t when the vehicle brakes. Here, the bead can preferably be arranged so that it can absorb these forces and prevent the fuel tank from slipping forward. Displacement of the fuel tank causes undesired forces on the connections and lines connected to the fuel tank.In addition, frequent displacements relative to the tensioning straps can cause damage to the surface of the reinforcement layer.

[0018] In addition, this design offers the advantage for assembly that the positioning of the fuel tank relative to the fastening device is clear, thus simplifying the installation of the connecting lines.

[0019] The advantages can be particularly well exploited if the bead is arranged directly next to the fastening device, which is arranged closer to the boss intended to accommodate the tank fitting. This can prevent undesirable stress on the tank fitting and connected lines due to displacement or expansion of the fuel tank. And positioning during assembly with regard to the connecting lines is easier. Furthermore, it can be advantageous to provide a second bead in the cylindrical central region on the outside, which is arranged next to the second fastening device. The beads rest against the respective fastening devices and are designed in such a way that the fuel tank cannot slip through the tensioning strap(s) of the fastening devices in either direction parallel to the tank's longitudinal direction.This is particularly advantageous for horizontal installation in the vehicle.

[0020] Furthermore, it is advantageous if the second of the two fastening devices is designed to be elastic and / or movable so that the fuel tank can expand in the tank's longitudinal direction. This can reduce unwanted transverse loading on the upper fastening device. In particular, the second fastening device is the one further away from the boss, which is intended to accommodate the tank fitting.

[0021] While with a vertically mounted fuel tank the weight force counteracts the upward displacement and therefore no securing is necessary in this direction, with a horizontal installation it can be advantageous to prevent slipping in both directions by means of a bead.

[0022] In a further preferred embodiment, the bead is annular and surrounds the fuel tank over its entire circumference.

[0023] In an alternative preferred embodiment, the bead is designed as one or more ring segments which at least partially surround the fuel tank on its circumference, wherein the ring segment(s) together preferably surround at least 20%, particularly preferably at least 40% of the circumference

[0024] In each of these cases, the bead is sufficient to prevent slippage in at least one direction. The bead can, for example, represent part of a circle or an ellipse in cross-section, or it can be rectangular.

[0025] The height of the bead is the extent to which the bead extends beyond the diameter of the cylindrical central section. The height of the bead can preferably be at least 10 mm, particularly preferably at least 20 mm. In particular, the height can be at least 2% of the diameter of the fuel tank in the cylindrical central section. Slippage can be reliably prevented by one of these designs.

[0026] The extension of the bead in the tank's longitudinal direction at the connection surface to the reinforcement layer can preferably be between 20 mm and 80 mm. This ensures sufficient stability and a sufficient connection to the reinforcement layer.

[0027] Advantageously, the bead can be made of a different material than the reinforcement layer. This allows for a particularly wear-resistant or easier-to-machine material to be used. For example, the bead can be made of metal, plastic, rubber, or a composite material. The bead can also be made of a combination of materials.

[0028] In particular, the bead can be attached to the outside of the fuel tank after the reinforcement layer has been manufactured. For example, the bead can be glued or vulcanized on. Alternatively, it can be pressed or clamped on. Or it can be secured against slipping along the fuel tank surface with a form-fitting connection on the outside of the reinforcement layer.

[0029] In a further advantageous embodiment, the bead can be made of fiber-reinforced plastic as an integral component of the reinforcement layer. Thus, the bead is manufactured directly during the production of the reinforcement layer. For example, after the reinforcement layer is wound, the bead is also wound onto the outer side before the resin of the reinforcement layer cures. This ensures a particularly good bond between the bead and the reinforcement layer.

[0030] To improve the bead's wear protection, a metallic element can be placed between the bead and the fastening device's clamping straps. This extends the bead's lifespan, particularly with plastic or rubber beading. The metallic element can, for example, be a sheet metal strip glued or vulcanized to the side of the bead that comes into contact with the fastening device. Or it can be implemented as a metallic coating.

[0031] In a particularly preferred embodiment, the fuel tank is designed for vertical installation in a gas-powered vehicle, in particular a commercial vehicle, with the bead being arranged directly above one of the two fastening devices. The fact that the bead is arranged above one of the fastening devices refers to the position when installed in the vehicle.

[0032] The bead is particularly preferably arranged directly above the lower of the two fastening devices. Here, too, this is based on the position when installed in the vehicle. This means that the two fastening devices are designed as an upper and a lower fastening device, based on the later position when installed in the vehicle. This holds the lower part of the fuel tank securely in position. The connections and lines for refueling and controlled gas release are usually located on the lower boss. These are thus protected from any forces that may occur when the fuel tank expands lengthwise. Expansion of the fuel tank lengthwise occurs when the internal tank pressure changes during filling or emptying. Further advantageous features of the invention are explained using exemplary embodiments with reference to the drawings.Similar parts are marked with the same reference symbols.

[0033] Fig.1 Schematic representation of a vehicle with a fuel tank according to the invention (side view)

[0034] Fig.2 Representation of a fuel tank according to the invention in

[0035] Side view and in section

[0036] Fig.3a / b / c Detailed representation of various designs of the bead on the fuel tank according to the invention in side view and section Fig.4 Example of a fastening device of a fuel tank Fig.5a Representation of another fuel tank according to the invention in

[0037] Side view

[0038] Fig.5b Representation of yet another inventive

[0039] Fuel tanks in side view

[0040] Fig. 1 shows the gas-powered vehicle 20. The vehicle 20 is preferably a commercial vehicle, for example a truck as shown here. Especially with gas-powered commercial vehicles, large quantities of fuel are required for an economically viable range. The drive can be provided, for example, by a fuel cell and electric motor or by a gas engine. The fuel can be hydrogen, biogas, methane, ethane, natural gas or a gas mixture. The gas is stored under pressure in the fuel tanks 1. A pressure of at least 200 bar, often up to 700 or 875 bar, is usually used. The vehicle 20 is shown with a fuel tank module, which usually has a plurality of fuel tanks 1 arranged next to one another in the transverse direction Q of the vehicle. The fuel tanks 1 are mounted vertically in the vehicle 20 so that the longitudinal direction t of the tanks is aligned essentially parallel to the vertical direction H of the vehicle.This allows for optimal use of the installation space, thus maximizing the possible tank volume, while simultaneously improving safety, as the tank fittings are well protected on the underside and not located on the side of the vehicle in a vulnerable area. Depending on the application, the fuel tanks can also be mounted horizontally next to the vehicle frame.

[0041] The fuel tank 1 has an elongated shape that is rotationally symmetrical to the tank's longitudinal direction t. In its central region, it has a cylindrical shape, which is closed at both ends by curved pole caps that terminate in a so-called boss 7. The upper boss 7 usually has a safety valve that releases the gas if the temperature or pressure is too high, thus relieving the tank, for example, in the event of a fire to prevent an explosion. The lower boss 7 has a tank fitting. This can be used to fill the fuel tank 1 with gas and to withdraw gas in a controlled manner during operation. The tank fittings can optionally include additional safety valves.

[0042] The fuel tank 1 is equipped with two fastening devices 2, 3, which comprise tensioning straps, for example, simple clamps or so-called articulated strap clamps. There is an upper fastening device 2 and a lower fastening device 3. The fuel tank is attached to the support structure 10 via both fastening devices 2, 3. If necessary, more than two fastening devices can be used, so that, for example, a central fastening device is also present.

[0043] In the illustrated case, the support structure 10 also supports the additional fuel tanks and serves to mount the fuel tank module in the vehicle 20. It can be designed, for example, as a steel frame. A protective cover 11 can be provided to protect the fuel tanks 1 from external influences.

[0044] The bead 6 on the outside of the reinforcement layer of the fuel tank 1 rests against the lower fastening device 3 and serves according to the invention to prevent the fuel tank 1 from slipping downwards through the tensioning straps of the lower fastening device 3. In addition, the bead 6 facilitates assembly by ensuring clear positioning of the fastening device 3 on the fuel tank 1. Fig. 2 shows an embodiment of the fuel tank 1 according to the invention. It comprises two fastening devices 2, 3, one being the upper fastening device 2 and one being the lower fastening device 3. Both are equipped with tensioning straps that surround the fuel tank around its circumference and are designed as clamps. In addition, the fastening devices 2, 3 each have a base 4, 5 to which the tensioning straps are attached and against which the fuel tank 1 is tensioned.With the help of the fastening devices 2, 3, the fuel tank 1 can be attached to the support structure 10. This support structure 10 serves to mount the fuel tank 1 in a vehicle. As shown here, the fuel tank 1 with its fastening devices 2, 3 is intended for vertical installation in a vehicle. The fuel tank 1 has a bead 6 on the outside, which rests against the lower fastening device 3 and ensures that the fuel tank 1 does not slip through the tensioning straps of this fastening device 3. This ensures that it is held securely and does not change its position even in the event of vibrations, which prevents damage to the tank surface.

[0045] In fuel tanks 1 that are filled at high pressure, the length of the tank changes depending on the internal pressure. The bead 6 maintains the fixed position of the fuel tank 1 relative to the lower mounting device 3. This protects the tank fittings and lines, which are usually connected to the lower boss, from additional and changing stress caused by the longitudinal expansion of the fuel tank 1.

[0046] Alternatively, the bead 6 can also be provided above the upper fastening device 2, as shown in Fig. 5a. This is particularly advantageous when the tank fittings are connected to the upper boss. This ensures that the position of the fuel tank 1 relative to the upper boss remains largely constant during longitudinal expansion.

[0047] Particularly when the fuel tank 1 is mounted horizontally in the vehicle, it may be expedient to provide two beads 6, as shown in Fig. 5b. The two beads 6 are arranged such that the fuel tank 1 cannot slip through the clamping straps in either direction along the tank's longitudinal direction t. Also in accordance with the invention are further embodiments with multiple fastening devices comprising clamping straps, and in which the bead rests against at least one of the fastening devices.

[0048] Fig.3a,b,c shows three different designs for the bead 6,6',6", regardless of the position in which the bead 6,6',6" is intended.

[0049] In Fig.3a, the bead 6 is formed as a ring on the entire circumference of the fuel tank 1.

[0050] Alternatively, the bead 6' can be formed only as a ring segment, as shown in Fig. 3b. Preferably, the bead 6' is applied to at least 20% of the circumference, as shown here.

[0051] In another variant, the 6" bead can consist of several ring segments arranged around the circumference of the fuel tank 1. Here, for example, there are four segments. Dividing the 6" bead into several ring segments simplifies the production and attachment of the 6" bead.

[0052] The bead 6, 6', 6" can be an integral part of the reinforcement layer or it can be manufactured separately and attached to the outside of the fuel tank 1, as previously described. If it is manufactured separately, the bead 6, 6', 6" can be made of a different material than the reinforcement layer of the fuel tank 1, for example, metal, plastic, rubber, or a composite material. To reduce wear on the bead 6, 6', 6" and thus extend its service life, a metallic element can be provided on the bead 6, 6', 6" for protection. This metallic element can be, for example, a sheet metal strip or a metallic coating on the side of the bead that comes into contact with the fastening device 3. The illustration in Fig. 4 shows an exemplary variant of the fastening device 3.The fastening device 3 comprises tensioning straps, which here are designed as articulated strap clamps, and a base 5 to which the tensioning straps are attached. Using this fastening device 3, the fuel tank can be attached to the support structure 10.

[0053] List of reference symbols

[0054] 1 fuel tank

[0055] 2 fastening device

[0056] 3 Fastening device

[0057] 4 Console

[0058] 5 Console

[0059] 6, 6',6" bead

[0060] 7 Boss

[0061] 10 Supporting structure

[0062] 11 Protective cover

[0063] 20 gas-powered commercial vehicles

[0064] H Height direction of the vehicle

[0065] L Longitudinal direction of the vehicle

[0066] Q Transverse direction of the vehicle t Longitudinal direction of the tank

Claims

Patent claims 1. Fuel tank (1) for storing gas for installation in a gas-powered vehicle, in particular a commercial vehicle (20), wherein the fuel tank (1) has an elongated shape, which is cylindrical in the central region and closed at both ends with domed end caps, and has a reinforcing layer made of fiber-reinforced plastic, as well as a metallic connector, a so-called boss, at each of the end caps, and wherein the fuel tank (1) has at least two fastening devices (2, 3) which, by means of tension bands, encompass the fuel tank (1) in the cylindrical central region and are provided for fastening the fuel tank (1) to a support structure (10), characterized in that the fuel tank (1) has at least one bead (6, 6', 6") on the outside in the cylindrical central region, which is arranged directly next to one of the fastening devices (2, 3) and thus abuts it and is designed in such a way thatthat the fuel tank (1) cannot slide through the tension strap(s) of this one fastening device (2,3) in any direction.

2. Fuel tank (1 ) according to claim 1 characterized in that the bead (6,6',6“) is arranged directly next to the fastening device (2,3) which is arranged closer to the boss which is provided to receive the tank fitting.

3. Fuel tank (1 ) according to claim 1 or 2 characterized in that the second of the two fastening devices (2,3) is designed to be elastic and / or displaceable in such a way that the fuel tank (1 ) can expand in the longitudinal direction t of the tank.

4. Fuel tank (1) according to one of the preceding claims, characterized in that a second bead (6;6',6") is provided on the outside of the cylindrical central region, which is arranged next to the second fastening device (2,3), wherein the bead(s) (6,6',6") abut the respective fastening devices (2,3) and are designed in such a way that the fuel tank (1) cannot slip through the tension band(s) of the fastening devices (2,3) in either direction.

5. Fuel tank (1) according to one of the preceding claims characterized in that the bead (6,6',6") is annular and surrounds the fuel tank (1) on its entire circumference.

6. Fuel tank (1 ) according to one of claims 1 to 4 characterized in that the bulge (6,6',6“) is designed as one or more ring segments which at least partially surround the fuel tank (1 ) on its circumference, wherein the ring segment(s) together preferably surround at least 20%, particularly preferably at least 40% of the circumference.

7. Fuel tank (1 ) according to one of the preceding claims characterized in that the bead (6,6',6“) is made of a different material than the reinforcing layer of the fuel tank (1 ).

8. Fuel tank (1 ) according to one of claims 1 to 6 characterized in that the bead (6,6',6“) is manufactured as an integral part of the reinforcement layer of the fuel tank (1 ).

9. Fuel tank (1 ) according to one of claims 1 to 7 characterized in that the bead (6,6',6“) has been attached to the outside of the fuel tank (1 ) after the tank wall has been manufactured.

10. Fuel tank (1 ) according to claim 9 characterized in that the bead (6,6',6“) is glued or vulcanized on.

11. Fuel tank (1) according to claim 9 characterized in that the bead (6,6',6") is pressed on or clamped.

12. Fuel tank (1 ) according to one of the preceding claims characterized in that the bead (6,6',6“) is positively attached to the outside of the fuel tank (1 ).

13. Fuel tank (1) according to one of the preceding claims characterized in that the bead (6,6',6") has a metallic element which is attached on the side which comes into contact with the fastening device (2,3).

14. Fuel tank (1 ) according to one of the preceding claims characterized in that the fuel tank is designed to be mounted vertically in a gas-powered vehicle, in particular a commercial vehicle (20) and that the bulge (6,6',6") is arranged directly above one of the two fastening devices (2,3).

15. Fuel tank (1) according to one of the preceding claims characterized in that the bead (6,6',6") is arranged directly above the lower of the two fastening devices (2,3).

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