Gas fuel storage assembly

Abstract

Gas fuel storage assembly for a heavy-duty vehicle (2), in particular a truck or a bus, comprising - at least two elongated gas storage tanks (3) arranged parallel to each other with a round cross-section, - a spacer arrangement designed to hold the gas storage tanks (3) at a distance, and - at least one belt (11) designed for attachment to a holder (9) attached to a vehicle chassis (10) and for clamping around the gas storage tanks (3) to compress them to form a tank package (4), characterized in that the spacer arrangement comprises at least one spring element (7) designed for arrangement in a space (8) formed between the gas storage tanks (3) before tensioning the belt (11), which is designed to be compressed by tensioning the belt (11), wherein the at least one spring element (7) is designed to store potential energy for pushing apart the gas storage tanks (3) by this tensioning of the belt (11) when compressed.

Description

TECHNICAL AREA OF INVENTION

[0001] The present invention relates to a gas fuel storage assembly for a heavy-duty vehicle according to the preamble of claim 1, wherein the heavy-duty vehicle can be, for example, a truck or a bus.

[0002] Such a gas fuel storage assembly is known from DE 20 2007 015 487 U1. Similar arrangements are described in CN 2 01 124 754 Y and US 2006 / 0 033 322 A1.

[0003] “Heavy goods vehicle” is defined here as a motor vehicle with an operating weight of more than 3.5 tonnes and includes, among other things, trucks and buses.

[0004] Equipping such a motor vehicle with a gas fuel storage assembly serves to keep the vehicle's production costs low. Ideally, the tank assembly is positioned where the fuel tank, for example for diesel, is to be mounted on other vehicles produced on the same production line, so that the tank assembly can be installed in a similar manner to other fuel tanks. This typically means that the gas storage tanks, usually four, are pre-assembled with the spacer arrangement within a tank assembly. They are lifted onto chassis-mounted brackets and then secured to these brackets by tensioning one or more straps.The spacer assembly typically includes a variety of spacer components, with the rubber elements being compressed by tensioning the belt to form the tank package and protecting the gas storage tanks from chafing.

[0005] To securely fasten the tank assembly to a heavy-duty vehicle like a truck, high tension forces in a belt, on the order of 30-45 kN, are required. However, the rigidity of the tank assembly can be partially compromised because the assembly includes spacers and rubber elements that deform and harden over time. Furthermore, the pressure in the gas storage tanks varies considerably, from approximately 15 to 200 bar during a driving cycle, causing changes in the tanks' circumference due to expansion and contraction. The circumference of steel gas storage tanks can change by up to 0.5% during a driving cycle, and this change can be even greater for composite gas storage tanks.One solution to this problem would be to provide a belt with a very strong spring; but this solution would not be attractive because it would reduce the volume available for the gas storage tanks, and it is desirable to keep this volume as large as possible in order to optimize the vehicle's range through the fuel contained in the gas storage tanks of the gas fuel storage assembly.

[0006] The object of the present invention is to provide a gas fuel storage assembly of the type defined above, which is improved in such a way that changes in the size of the individual gas storage tanks occurring during operation are advantageously taken into account without subjecting the gas storage tanks to undesirable mechanical stresses.

[0007] This problem is solved according to the invention by a gas fuel storage assembly with the features of patent claim 1.

[0008] Thus, the spacer assembly is equipped with at least one spring element designed to be positioned in a space formed between the gas storage tanks before the belt is tensioned and compressed by this tensioning. This spring element stores potential energy for pushing the gas storage tanks apart. The potential energy stored in the at least one spring element ensures that the tank assembly is securely fastened to the vehicle chassis without the risk of movements such as vibrations between the gas storage tanks, independent of changes in gas pressures within the gas storage tanks and deformations or hardening of the spacer elements. Furthermore, this is achieved without affecting the total possible volume of gas that can be stored in the tank assembly, since the already available space between the gas storage tanks is used to accommodate means in the form of the at least one spring element for holding the tank assembly as a rigid unit.Another advantage of arranging the at least one spring element in the space between the gas storage tanks instead of in the at least one belt is the elimination of the dependence on friction that occurs when the belt would otherwise have to slide relative to the tank pack during the action of the spring element.

[0009] According to one embodiment of the invention, the at least one spring element is designed to be pre-tensioned and placed in the space before the belt is tensioned. This optimizes the effective spring travel.

[0010] According to a further embodiment of the invention, the at least one spring element is a mechanical spring. This choice of spring element results in high reliability at favorable costs.

[0011] According to a further embodiment of the invention, the at least one spring element is a disc spring. The use of one or more disc springs as spring elements enables the provision of high spring stiffness with a short spring travel, which makes such spring elements particularly advantageous considering the limited space available.

[0012] According to a further embodiment of the invention, the spacer arrangement comprises at least two sets with at least one spring element, which act on planes perpendicular to the longitudinal extent of the gas storage tanks and are alternately offset from each other along the longitudinal extent of the gas storage tanks. Arranging a plurality of such sets of spring elements increases the total spring force acting to stabilize the existing tank assembly.

[0013] According to a further embodiment of the invention, the gas fuel storage assembly comprises four gas storage tanks configured to form a tank package by tensioning the at least one belt. The use of four gas storage tanks in a tank package leads to efficient use of the available volume for the tank package and provides suitable space between the gas storage tanks for use with the arrangement of the at least one spring element. According to a further development of this embodiment, the gas storage tanks are arranged to each form a corner of a substantially square cross-section of the tank package, and the spacer arrangement comprises four spring elements acting on a plane perpendicular to the longitudinal extent of the gas storage tanks, such that each gas storage tank is linked to two acting spring elements to push it away from each of the two gas storage tanks adjacent to it.By providing such a set of four spring elements acting on one plane, the total force for pushing the gas storage tanks apart is distributed across these spring elements, which allows for a large spring deflection, i.e., elastic deflection.

[0014] According to a further embodiment of the invention, the at least one strap is designed for attachment to a holder attached to the chassis of the vehicle in order to enclose the tank package of gas storage tanks together with the holder.

[0015] According to a further embodiment of the invention, the gas storage tanks consist of steel or a composite material, which are suitable materials for such gas storage tanks.

[0016] The invention also relates to a heavy-duty vehicle, in particular a truck or a bus, which is equipped with a gas fuel storage assembly according to the invention, wherein the vehicle may also be equipped with two or more gas fuel storage assemblies in order to be able to store a larger quantity of gas fuel to increase the possible range of the vehicle.

[0017] Other advantageous features and benefits of the present invention will become apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] With reference to the attached drawings, a detailed description of an embodiment of the invention follows, which is cited as an example.

[0019] The drawings show the following: Fig. Figure 1 shows a schematic view illustrating how a gas fuel storage assembly according to the present invention can be arranged in a heavy-duty vehicle in the form of a truck. Fig. Figure 2 shows a perspective view of a pre-assembled tank package as part of a gas fuel storage assembly according to an embodiment of the invention, which is ready to be lifted onto holders attached to the chassis of a motor vehicle. Fig. Figure 3 shows a view illustrating the gas fuel storage assembly with the tank package on supports by tensioning a belt attached to it. DETAILED DESCRIPTION OF ONE EXECUTION OF THE INVENTION

[0020] Fig. Figure 1 shows a highly schematic representation of a possible position of a gas fuel storage assembly 1 according to the present invention in a heavy-duty vehicle 2 in the form of a truck, at a location where a liquid fuel tank, containing, for example, diesel fuel, is normally located for such a vehicle. A number of vehicle components have been omitted because they are not related to the present invention concerning the design of a gas fuel storage assembly for such a vehicle.

[0021] The following is a gas fuel storage assembly according to an embodiment of the present invention with regard to Fig. 2 and Fig. 3 described. This gas fuel storage assembly comprises four elongated gas storage tanks 3 arranged parallel to one another, each with a circular cross-section, forming a tank package 4 with a substantially square cross-section. Each gas storage tank typically has a volume on the order of 100 liters, for example, by having a length of 1500 mm and a diameter of 320 mm; however, any volume size is conceivable. The gas storage tanks can contain any type of gas suitable for powering a vehicle, such as biogas. Fig. Figure 2 shows the tank package 4 in a pre-assembled state in which the gas storage tanks 3 are held in place by any form of strip-shaped elements (not shown) and in which a spacer arrangement is part of the tank package for keeping the gas storage tanks 3 at a distance.

[0022] The spacer arrangement comprises spacers 5 wedged between adjacent gas storage tanks 3, and at least one set 6 of four spring elements 7 in the form of disc springs arranged in a space 8 bounded by and between the gas storage tanks 3. These spring elements 7 act on a plane perpendicular to the longitudinal extent of the gas storage tanks, so that each gas storage tank 3 is connected to two spring elements that act to push away each of the two gas storage tanks adjacent to it. Support elements 12 with a surface designed to follow and bear on the circumferential surface of a gas storage tank 3 form supports for the spring elements 7, on which these act.

[0023] Fig. Figure 3 shows a gas fuel storage assembly according to an embodiment of the invention, in which the pre-assembled tank package 4 consists of Fig. 2 was placed on one or more brackets 9 attached to the chassis 10 of the vehicle, and one or more straps 11 attached to the bracket 9 were tensioned around the tank package 4 to press the gas storage tanks 3 towards each other, that is, without touching each other, while the spring elements 7 are compressed to store potential energy for pushing the gas storage tanks 3 apart, resulting in a very firm and stable tank package unit. If the circumference of the gas storage tanks 3 decreases due to lower gas pressure within them, the spring elements 7 extend and push the gas storage tanks 3 apart to brace themselves firmly against the strap 11. Conversely, if the circumference of the gas storage tanks 3 increases due to higher gas pressure within them, the spring elements 7 are compressed instead and push the gas storage tanks 3 against the strap 11. The gas storage tank 3' in Fig. 3 is linked to two spring elements 7', 7" which push it away from each of the two adjacent gas storage tanks 3 and 3".

[0024] Due to the longitudinal extent of the gas storage tanks 3, the spring arrangement can comprise several sets 6 of spring elements 7 acting on planes perpendicular to the longitudinal extent of the gas storage tanks and offset from each other along this longitudinal extent, approximately one plane from each point of the Fig. 2 spacers shown 5, which then means three such sets.

[0025] The invention is of course by no means limited to the embodiment described above, since many possibilities for modifications thereof are clear to a person skilled in the art without having to deviate from the scope of the invention as defined in the attached claims.

[0026] The number of gas storage tanks in the gas fuel storage assembly may be other than four in each tank package, and the assembly may include more than one tank package, or the vehicle may have more than one gas fuel storage assembly.

[0027] Other spring elements besides disc springs can be used, including non-mechanical springs; however, disc springs are particularly advantageous due to the possibility of achieving high spring stiffness with a short spring travel. The spring stiffness can be changed by altering the number of discs used to form each spring and the design of each disc.

Claims

[1] Gas fuel storage assembly for a heavy-duty vehicle (2), in particular a truck or a bus, comprising - at least two elongated gas storage tanks (3) arranged parallel to each other with a round cross-section, - a spacer arrangement designed to hold the gas storage tanks (3) at a distance, and - at least one belt (11) designed for attachment to a holder (9) attached to a vehicle chassis (10) and for clamping around the gas storage tanks (3) to compress them to form a tank package (4), characterized by, that the spacer arrangement comprises at least one spring element (7) designed for arrangement in a space (8) formed between the gas storage tanks (3) before tensioning the belt (11), which is designed to be compressed by tensioning the belt (11), wherein the at least one spring element (7) is designed to store potential energy for pushing apart the gas storage tanks (3) by means of this tensioning of the belt (11) when compressed. [2] Gas fuel storage assembly according to claim 1, characterized by , that at least one spring element (7) is designed to be placed in space (8) under preload. [3] Gas fuel storage assembly according to claim 1 or 2, characterized by , that at least one spring element (7) is a mechanical spring. [4] Gas fuel storage assembly according to claim 3, characterized by , that at least one spring element (7) is a disc spring. [5] Gas fuel storage assembly according to any one of the preceding claims, characterized by , that the spacer arrangement comprises at least two sets (6) with at least one spring element (7) which act on planes perpendicular to the longitudinal extent of the tanks (3) and are arranged offset from each other along the longitudinal extent of the tanks. [6] Gas fuel storage assembly according to any one of the preceding claims, characterized by , that it comprises four gas storage tanks (3) designed to form a tank package (4) by tensioning at least one belt (11). [7] Gas fuel storage assembly according to claim 6, characterized by, that the gas storage tanks (3) are arranged to form each corner of a substantially square cross-section of the tank package (4), and that the spacer arrangement comprises four spring elements (7) acting on a plane perpendicular to the longitudinal extension of the gas storage tanks (3), such that each gas storage tank (3) is linked to two spring elements (7) which act to push it away from each of the two gas storage tanks (3) adjacent to it. [8] Gas fuel storage assembly according to any one of the preceding claims, characterized by , that at least one belt (11) is designed to be attached to the holder (9) attached to the vehicle chassis (10) of the vehicle (2) in order to enclose the tank package (4) of gas storage tanks (3) together with the holder (9). [9] Gas fuel storage assembly according to any one of the preceding claims, characterized by , that the gas storage tanks (3) are made of steel or a composite material. [10] Heavy goods vehicle, in particular a truck or a bus, characterized by that it is equipped with a gas fuel storage assembly (1) according to one of the preceding claims. [11] Heavy goods vehicle according to claim 10, characterized by that it is equipped with two or more gas fuel storage assemblies (1).

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