Fuel tank module
Patent Information
- Application Number
- EP2023708430
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-03-24
- Filing Date
- 2023-02-24
- Publication Date
- 2025-02-05
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing fuel tank modules for commercial vehicles face challenges in securely attaching large, high-pressure gas tanks while minimizing weight and space, as traditional fastening devices are not stable enough to reliably fasten long, heavy tanks without increasing the vehicle's payload and installation space requirements.
The fuel tank module employs a support structure with longitudinal supports and a connecting device that wraps around the circumference of individual tanks, utilizing their inherent rigidity to enhance stability, and additional fastening devices with tension straps to secure the tanks, allowing for elastic movement and vibration damping, thus increasing rigidity without adding weight or size to the support structure.
This design increases the natural frequency of tank movement, prevents swinging, and allows for expansion without straining the connecting device, resulting in a more stable and space-efficient fuel tank module that maintains mechanical stability and reduces weight and installation space requirements.
Smart Images
Figure 1.1
Abstract
Description
[0001] Fuel tank module
[0002] The invention relates to a fuel tank module for storing gas for installation in a gas-powered vehicle, in particular a commercial vehicle. The fuel tank module comprises a plurality of individual tanks, a support structure to which the individual tanks are attached, and at least one fastening device that holds the individual tank with the aid of one or more tensioning straps and connects it to the support structure. The support structure is intended to fasten the fuel tank module to the vehicle. The individual tanks have an elongated shape that is cylindrical in the central region and closed at both ends by curved pole caps. The individual tanks have a reinforcing layer made of fiber-reinforced plastic and a metallic connecting piece, a so-called boss, on each of the pole caps.
[0003] The support structure is used to mount the fuel tank module to the vehicle frame.
[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, often up to 700 bar or 875 bar, are typical for such pressure tanks. This means that the tank must not only be gas-tight under this pressure, but also require high mechanical stability. In addition, the fuel tank must be large enough for commercial vehicles, 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 considerable and expand lengthwise when exposed to corresponding internal pressure. Due to their high compressive strength, such individual tanks can weigh up to 300 kg.The individual tanks are designed primarily as hydrogen tanks, for example, for vehicles with fuel cell drives or gas engines. The individual tanks can also be designed for biogas, propane, methane, natural gas, or gas mixtures.
[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 tank modules that are mounted vertically in the vehicle are also known in the prior art, as shown, for example, in document US 2019 / 0255941 A1. This offers the advantage that the individual tanks can be accommodated behind the driver's cab in a space-saving manner, especially in commercial vehicles. In the design shown there, the individual tanks are attached with a fastening device that engages the boss at the top and bottom. However, the box shown, in which the individual tanks are mounted, requires additional installation space and increases the weight, so that for a given tank volume, the space for superstructures and the commercial vehicle's payload is reduced.
[0008] Furthermore, fuel tank modules are known from DE 202007015487 U1, in which the individual 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 fitting is provided at one end of the tank through which the tanks are filled and emptied. The fastening devices shown here are not stable or rigid enough to reliably attach large, long individual tanks, such as those required in commercial vehicles.
[0009] The object of the invention is to provide an improved fuel tank module that reliably supports the individual tanks and is designed to save weight and space, making it particularly suitable for commercial vehicles with high tank volumes. A secure yet space- and weight-saving attachment is essential.
[0010] The object is achieved by a fuel tank module according to claim 1. Further advantageous features are mentioned in the respective dependent claims.
[0011] According to the invention, the fuel tank module according to claim 1 is characterized in that the support structure comprises at least two longitudinal supports, which are each arranged in the space between two of the individual tanks, wherein on each of the longitudinal supports two of the individual tanks are each provided with at least one
[0012] fastening device, and wherein at least one
[0013] A connecting device is provided which connects one of the individual tanks, which is fastened to one longitudinal support, to one of the individual tanks, which is fastened to the second longitudinal support, in which the connecting device wraps around these two individual tanks at least partially at their circumference.
[0014] The advantage of such an inventive design is that the rigidity of the individual tanks themselves is used to make the entire fuel tank module more stable. The rigidity of the individual tanks is achieved through the reinforcement layer made of fiber-reinforced plastic. This rigidity is particularly high when CFRP is used. The supporting structure can thus be designed slimmer, smaller, and lighter. The connecting device ensures that the two pairs of individual tanks, each attached to a longitudinal support of the supporting structure, cannot vibrate against each other. Above all, the inventive design increases the natural frequency for the eigenmodes at which the pairs of individual tanks shift or twist against each other. This is only possible by increasing the rigidity without also increasing the weight. This would inevitably be the case with a stiffer design of the supporting structure or other reinforcements.
[0015] In a particularly preferred embodiment, the connecting device has no connection to the support structure; it only connects the two individual tanks to be connected. Thus, the forces between the individual tank pairs are absorbed solely by the connecting device and the individual tanks, and the support structure is not subjected to additional stress. It can be designed smaller and lighter. Furthermore, the support structure can be lower, while the connecting device can still be located at the end facing away from the individual tanks.
[0016] To securely hold the individual tanks and increase the rigidity of the entire module, it is advisable to have at least one additional fastening device for each individual tank. This connects the individual tank to the supporting structure by securing it with one or more tension straps or by holding it to its boss. Two fastening devices per individual tank are necessary, especially for long individual tanks.
[0017] Preferably, the connecting device is designed such that it is elastic or displaceable in the direction of the longitudinal direction (t) and is rigid perpendicular to the longitudinal direction (t), thus allowing a relative movement along the longitudinal direction (t) between the two connected individual tanks.
[0018] A key advantage of this design is that it allows the two individual tanks to expand to varying degrees or shift longitudinally relative to one another without placing excessive strain on the connecting device, which could then cause damage. This type of expansion occurs primarily when there are pressure differences within the individual tank when the tank is filled to up to 875 bar or, once emptied, is subjected to a lower pressure. Expansion is particularly important for larger individual tanks, such as those required in commercial vehicles to provide sufficient tank capacity. Such individual tanks for commercial vehicles can be as much as 2500 mm long and over 500 mm in diameter. The expansion then ranges from several millimeters to a few centimeters in the longitudinal direction. Such dimensions are not known for individual tanks for passenger vehicles; they are usually only around 1000 mm long.
[0019] In this context, elastic means that elastic movement is permitted by the connecting device undergoing controlled elastic deformation. Rigid is considered here that the connecting element is designed in such a way that it allows virtually no movement or deformation in this direction under normal loading.
[0020] In an advantageous embodiment, the connecting device comprises two cables arranged crosswise between the two connected individual tanks. Cables, in this context, are understood to be suitable for absorbing essentially only tensile forces. The cables can also be designed as a band. The crossed arrangement of the two cables prevents or at least dampens any vibration between the individual tank pairs. In particular, the cables can also be made of an elastic material.
[0021] In a further advantageous embodiment, the connecting device is equipped with two tensioning straps, each of which wraps around one of the individual tanks. The two individual tanks are thus held together by the two tensioning straps of the connecting device. The tensioning straps can be designed, for example, as simple clamps or as so-called articulated clamps, both on the connecting device and on the fastening devices.
[0022] In particular, the connecting device comprises a connecting bracket which is arranged between the two connected individual tanks. For example, this connecting bracket can hold the two tensioning straps together. The connecting bracket is preferably made of rubber or elastomer or of metal and rubber. This not only enables elastic movement in the longitudinal direction t of the individual tanks relative to one another, but also provides a certain degree of damping of vibrations between the individual tanks. The damping effect reduces the amplitude of any vibration that may be excited so that no critical condition or damage occurs. In addition, the connecting bracket can be made of rubber, for example, and have metal strips on the sides to protect it against wear on the contact surface with the individual tanks.
[0023] In another advantageous design, the connecting bracket consists of two separate parts. This simplifies assembly, for example.
[0024] Particularly preferably, the support structure is designed such that it has a height h less than the length T of the individual tanks, in particular such that the height h is between 50% and 70% of the length T of the individual tanks. For this purpose, the connecting device is arranged in the tank's longitudinal direction t between the end of the support structure and the boss facing away from the support structure. In a design with a vertical arrangement of the individual tanks, this is, for example, the upper boss.
[0025] In a further embodiment, the connecting device is arranged closer to the end of the cylindrical part of the connected individual tanks than the respective fastening device.
[0026] Such designs ensure that the fuel tank module is sufficiently rigid and stable without the required support structure becoming too large or heavy. This means that both the installation space and the weight of the payload are not unnecessarily reduced. The rigidity of the fuel tank module is increased despite the relatively low support structure by arranging the connecting device at the end of the individual tanks facing away from the support structure. The fuel tank module can be further improved if the support structure includes two cross braces that connect the longitudinal supports, and if the support structure includes a floor brace that connects the cross braces and the longitudinal supports. This allows the support structure to be stiffer and even lower and lighter.
[0027] Further advantageous features of the invention are explained using exemplary embodiments with reference to the drawings. Similar parts are designated by the same reference numerals.
[0028] Fig.1 Schematic representation of a vehicle with a fuel tank module according to the invention (side view)
[0029] Fig.2a Representation of a fuel tank module according to the invention
[0030] Fig.2b Detailed view of the supporting structure
[0031] Fig.3a / b Sectional view and top view of an inventive
[0032] Fuel tank module
[0033] Fig.4 Top view of a further embodiment of an inventive
[0034] Fuel tank module
[0035] Fig.5a / b / c Detailed illustration of various designs for a connecting device with connecting console
[0036] Figure 1 shows a gas-powered vehicle 30, in this case a commercial vehicle, with the fuel tank module 20 according to the invention. The fuel tank module 20 is designed so that the four individual tanks 1.1, 1.2, 1.3, and 1.4 can be mounted vertically behind the driver's cab. This maximizes the available space and protects the individual tanks and their fittings from damage.
[0037] The individual tanks 1.1, 1.2, 1.3, 1.4 have an elongated shape with a longitudinal axis (t) that is cylindrical in the central region and closed at both ends by curved pole caps. The individual tanks 1.1, 1.2, 1.3, 1.4 comprise a reinforcement layer made of fiber-reinforced plastic, preferably CFRP, and a metallic connecting piece, a so-called boss 2, 3, on each of the pole caps. The individual tanks 1.1, 1.2, 1.3, 1.4 are each attached to the support structure 10 with two fastening devices 4, 5, which enclose the individual tanks 1.1, 1.2, 1.3, 1.4 with tensioning straps. Not visible in the side view are the two longitudinal supports of the supporting structure, to which two of the individual tanks 1.1, 1.2, 1.3, and 1.4 are each attached. Also not visible in this illustration is the connecting device that connects two of the individual tanks, here the two middle individual tanks 1.2 and 1.3.
[0038] Fig. 2a shows the fuel tank module 20 according to the invention, and Fig. 2b shows the support structure 10 alone as a detail. The fuel tank module 20 is designed for vertical installation of the individual tanks in the vehicle.
[0039] The fuel tank module 20 here comprises exactly four individual tanks 1 .1, 1 .2, 1 .3, 1 .4. Two individual tanks are each mounted on one of the longitudinal supports of the support structure 10, each with two fastening devices - here an upper and a lower one. The individual tanks 1 .1, 1 .2 are attached to the longitudinal support 11, and the individual tanks 1 .3, 1 .4 are attached to the longitudinal support 12. Each of the individual tanks is attached with a fastening device 4 in the lower region of the cylindrical part of the individual tank and with a fastening device 5 in the central region of the cylindrical part of the individual tank. All fastening devices 4, 5 are designed here with tensioning straps that enclose the individual tanks around the circumference. The tensioning straps are designed here as simple clamps with a tension lock. The lower fastening device 4 could alternatively also be designed to hold the individual tank to the lower boss 3.
[0040] Between the longitudinal supports 11, 12, the support structure 10 is provided with cross braces 13, 14, creating a box-like structure that can support the weight of the individual tanks. A floor brace 15 is also provided for reinforcement, which also serves for attachment to the vehicle. Since the longitudinal supports 11, 12 are each arranged in the space between two individual tanks, the support structure can be very narrow and lightweight. The longitudinal supports 11, 12 have attachment options for the fastening devices 4, 5, such as the attachment options 12a, 12b shown.
[0041] For stability and vibration reasons, the support structure 10 would also have to have a canted bracing at the top edge, like the one at the bottom, to prevent the box structure from deforming into a parallelogram or similar. Particularly useful for longer individual tanks, such as those used in commercial vehicles, the selected box structure would be relatively slim and tall, and thus particularly susceptible to such deformations. However, such bracing at the top edge is only possible if the support structure extends upwards above the individual tanks, as is known in the prior art. This would make the support structure larger and heavier, which is disadvantageous.
[0042] With the inventive design, the support structure 10 can be made lower and lighter without causing stability or vibration problems. The connecting device 6, which connects the two central individual tanks 1.2, 1.3, utilizes the rigidity of the individual tanks to make the entire fuel tank module 20 more stable. Furthermore, the natural frequency of the modes in which the two central individual tanks 1.2, 1.3 shift or twist relative to each other is significantly increased, so that they are no longer excited during normal operation.
[0043] The connecting device 6 can be designed, as shown here, with two tensioning straps, each of which wraps around one of the individual tanks 1, 2, 1, 3, and with a connecting bracket that connects the tensioning straps. The connecting bracket is preferably designed with damping. Here, too, the tensioning straps are designed as clamps with a tension lock.
[0044] Fig. 3a shows a sectional view at height AA. The support structure 10 comprises the longitudinal supports 11, 12, to each of which two individual tanks are attached using the respective fastening device 5, and the cross braces 13, 14. The fastening devices 5 can each be attached to the longitudinal support 11, 12 via a bracket.
[0045] The illustration in Fig. 3b shows the top view. On the middle individual tanks 1.2, 1.3, the connecting device 6 with the two tensioning straps 7.1, 7.2 and the connecting bracket 8 can be seen. The connecting bracket 8 is made of two parts and made of rubber, so that any vibrations that may occur can be optimally dampened. To protect the rubber parts against wear, the connecting bracket can be provided with metal strips on the sides in the contact area with the individual tanks. By means of the connecting device 6, which is arranged closer to the upper boss 2 than the upper fastening devices 5, the rigidity of the fuel tank module 20 can be increased without the supporting structure having to be made higher and thus heavier.
[0046] Fig. 4 shows an alternative embodiment to the variant shown in Fig. 3b. The connecting device 6' has two cables 9.1, 9.2 that are stretched crosswise and thus diagonally between the two individual tanks 1.2, 1.3. The cables 9.1, 9.2 are each attached at their ends to the support structure 10. The cables 9.1, 9.2 can be made of plastic or as steel cables, for example. The special arrangement of the cables 9.1, 9.2 prevents the individual tanks 1.2, 1.3 from shifting or twisting relative to one another. This prevents unwanted vibrations.
[0047] Figs. 5a, 5b, 5c show different embodiments for the connecting device 6. In all variants, the two tensioning straps 7.1, 7.2 are present to wrap around the respective individual tanks. The embodiments differ in the connecting bracket 8, which holds the tensioning straps 7.1, 7.2 together and thus connects the individual tanks. The connecting bracket can be adapted depending on the desired rigidity and damping properties. In Fig. 5a, the connecting bracket 8 is made as a component made of plastic or rubber. Due to its hollow design, the connecting bracket 8 is so elastic in the longitudinal direction t of the individual tank that it allows different longitudinal expansion of the individual tanks in their mobility. The material is also vibration-damping. The connecting webs between the two flanks are designed as two separate areas. Another design is shown in Fig.5b, which differs only in that the connecting webs between the flanks are designed as a continuous surface. In both variants, a metal strip can also be provided on the flanks to protect the connecting bracket 8 at the contact surface with the individual tanks from abrasion and wear. A third embodiment is shown in Fig. 5c. Here, the connecting bracket 8 consists of two separate parts 8a, 8b. These are also preferably made of plastic or rubber. And they are hollow.
[0048] List of reference symbols
[0049] 1.1 , 1.2, 1.3, 1.4 single tank
[0050] 2, 3 Boss
[0051] 4 Fastening device
[0052] 5 Fastening device
[0053] 6, 6' connecting device
[0054] 7.1 , 7.2 Tension strap
[0055] 8 Connection console
[0056] 8a, 8b Parts of the connecting console
[0057] 9.1 , 9.2 Rope
[0058] 10 Supporting structure
[0059] 11 , 12 Longitudinal support
[0060] 12a, 12b Mounting option
[0061] 13, 14 Cross bracing
[0062] 15 Floor bracing
[0063] 20 Fuel tank module
[0064] 30 vehicle h height of the supporting structure
[0065] H Height direction of the vehicle
[0066] L Longitudinal direction of the vehicle
[0067] Q Transverse direction of the vehicle t Longitudinal direction of the tank
[0068] T Length of the individual tank
Claims
Patent claims 1. Fuel tank module (20) for storing gas, for installation in a gas-powered vehicle (30), in particular a commercial vehicle, comprising at least four individual tanks (1.1, 1.2, 1.3, 1.4) arranged side by side, a support structure (10) to which the individual tanks (1.1, 1.2, 1.3, 1.4) are attached and which is designed to attach the fuel tank module (20) to the vehicle (30), and for each individual tank (1.1, 1.2, 1.3, 1.4) at least one fastening device (5) which holds the individual tank (1.1, 1.2, 1.3, 1.4) by means of one or more tension straps and connects it to the support structure (10), wherein the individual tanks (1.1, 1.2, 1.3, 1.4) have an elongated shape with a longitudinal axis (t) exhibiting a cylindrical shape in the central area and terminated at both ends with domed polar caps, wherein the individual tanks (1 .1 ,1 .2, 1.3,1 .4) a reinforcing layer made of fiber-reinforced plastic and a metallic connector, a so-called boss (2,3), at each of the polar caps, characterized in that the supporting structure (10) comprises at least two longitudinal supports (11, 12), each of which is arranged in the space between two of the individual tanks (1.1, 1.2, 1.3, 1.4), wherein two of the individual tanks are attached to each of the longitudinal supports (11, 12) with at least one fastening device (5), and wherein at least one connecting device (6, 6') is provided which connects one of the individual tanks. (1.1.1.2.1.3.1.4), which is attached to one longitudinal support (11), connects to one of the individual tanks (1.1, 1.2, 1.3, 1.4), which is attached to the second longitudinal support (12), by connecting the connecting device (6, 6') these two individual tanks (1.1.1.2.1.3.1.4) each at least partially encircles its circumference.
2. Fuel tank module (20) according to claim 1 characterized in that the connecting device (6,6') has no connection with the supporting structure (10).
3. Fuel tank module (20) according to claim 1 or 2 characterized in that for each individual tank (1.1 , 1.2, 1.3, 1.4) at least one further fastening device (4) is provided, which connects the individual tank (1.1 , 1.2, 1.3, 1.4) to the support structure (10) by holding it with the aid of one or more tension bands or by holding it on its boss (2,3).
4. Fuel tank module (20) according to one of the preceding claims characterized in that the connecting device (6,6') is designed to be elastic or displaceable in the direction of the longitudinal direction (t) and rigid perpendicular to the longitudinal direction (t), thus allowing relative movement along the longitudinal direction (t) between the two connected individual tanks.
5. Fuel tank module (20) according to one of the preceding claims characterized in that the connecting device (6,6') has two ropes (9.1 ,9.2) which are arranged crosswise between the two connected individual tanks (1 .1 , 1 .2, 1 .3, 1 .4).
6. Fuel tank module (20) according to one of claims 1 to 4 characterized in that the connecting device (6,6') has two tension bands (7.1 ,7.2) which each encircle one of the individual tanks (1 .1 ,1 .2,1 .3,1 .4).
7. Fuel tank module (20) according to one of the preceding claims characterized in that the connecting device (6,6') comprises a connecting console (8) which is arranged between the two connected individual tanks (1 .1 ,1 .2,1 .3,1 .4) and which in particular holds together the two tension bands (7.1 ,7.2).
8. Fuel tank module (20) according to claim 7 characterized in that the connecting console (8) is made of rubber or elastomer or of metal and rubber.
9. Fuel tank module (20) according to claim 7 or 8 characterized in that the connecting console (8) consists of two separate parts (8a, 8b).
10. Fuel tank module (20) according to one of the preceding claims characterized in that the support structure (10) has a lower height h than the length T of the individual tanks, in particular that the height h is between 50% and 70% of the length T of the individual tanks, and that the connecting device (6,6') is arranged in the longitudinal direction t of the tank between the end of the support structure (10) and the boss (2,3) located further away from the support structure.
11. Fuel tank module (20) according to one of the preceding claims characterized in that the connecting device (6,6') is arranged closer to the end of the cylindrical part of the connected individual tanks (1 .1 ,1 .2,1 .3,1 .4) than the respective fastening device (5).
12. Fuel tank module (20) according to one of the preceding claims characterized in that the supporting structure (10) comprises two cross braces (13,14) connecting the longitudinal supports (11,12) to each other, and that it comprises a bottom brace (15) connecting the cross braces (13,14) and the longitudinal supports (11,12) to each other.