DRAG REDUCTION DEVICE, DRAG REDUCTION DEVICE MANUFACTURING METHOD AND VEHICLE

Description

1 / 24 “DRAG REDUCTION DEVICE, METHOD OF MANUFACTURING THE DRAG REDUCTION DEVICE AND VEHICLE” TECHNICAL FIELD

[001] This disclosure relates generally to a method of producing a drag reduction device for a heavy vehicle. This disclosure also relates to a drag reduction device for a heavy vehicle and to a vehicle comprising said drag reduction device. FUNDAMENTALS

[002] It is well known that a significant amount of air drag occurs when a vehicle travels on a road due to air resistance, and this resistance increases with increasing vehicle speed. Air drag must be compensated for by the propulsion power supplied and therefore increases the vehicle's energy consumption. This, in turn, increases the vehicle's operating costs and may also, depending on the type of vehicle, have a negative environmental impact due to increased emissions. To reduce air resistance and consequently also the vehicle's energy consumption, the vehicle can be equipped with various types of drag reduction devices. Examples of larger drag reduction devices for heavy vehicles include roof air deflectors, side skirts, side air deflectors, and rear air deflectors.

[003] Drag reduction devices for heavy vehicles can, for example, be made of metallic materials, such as aluminum alloys, or of fiber-reinforced polymer compounds, depending on the type of drag reduction device and the desired properties.

[004] Sheet Molding Compound (SMC) is a widely used technique in the plastics manufacturing industry, used to produce Petition 870250092085, dated 08 / 10 / 2025, page 8 / 39 2 / 24 composite components that are strong, lightweight, and durable. The material is a type of glass fiber reinforced polyester that can undergo compression molding. The material can be supplied ready to mold or mixed on-site. The fibers can typically be cut fibers with a length of about 3-6 mm. SMC is a manufacturing process that can be used to create large and complex components with high strength-to-weight ratios and is therefore frequently used in the automotive industry today. However, SMC requires specialized equipment and is associated with high tooling costs. Another disadvantage of SMC is that the material is difficult to recycle and is not environmentally friendly.

[005] Vehicle manufacturers today face the problem of meeting a wide variety of end-user requirements for the vehicles they produce, including different vehicle configurations and sizes. This, in turn, leads to the need to offer a wide variety of shapes and sizes of drag reduction devices. Modularization is a strategy that can be used to improve a vehicle manufacturer's ability to efficiently provide end users, i.e., customers, with a wide variety of customized products. The concept of modularization aims to provide the widest possible range of products to customers with a minimum number of items, given the applications defined by the customers. This strategy can also be used in the production of drag reduction devices.For example, side skirts of different lengths can be supplied by producing modular SMC parts and assembling them to obtain the desired final shape of the side skirt by mounting them on a common metal support structure. The metal support structure also ensures that the assembled side skirt has sufficient mechanical properties to withstand the forces to which it may be subjected during vehicle operation, thus being a component. Petition 870250092085, dated 08 / 10 / 2025, page 9 / 39 3 / 24 essential side skirts comprising SMC panels. While the use of modularization can reduce tooling costs to accommodate a variety of side skirt shapes and sizes, the metal support structure adds weight and consumes space on board the vehicle. SUMMARY

[006] The objective of the present invention is to enable the cost-effective production of drag reduction devices with low weight and sufficient mechanical properties, which would allow the manufacturer to offer a variety of different shapes and sizes of such drag reduction devices.

[007] According to the present disclosure, a method for producing a drag reduction device for a heavy vehicle is provided. The method comprises the following steps: (a) provide a mold adapted to the geometric configuration of the drag reduction device to be produced, (b) arrange a plurality of sub-preforms in said mold so that the sub-preforms are arranged side by side or in a partially overlapping arrangement, with a longitudinal direction of each of the plurality of sub-preforms corresponding to a longitudinal direction of the drag reduction device to be produced, (c) provide a resin, either by resin application or resin infiltration, to the plurality of sub-preforms arranged in the mold, unless the plurality of sub-preforms is already fully impregnated with said resin, and (d) heat treatment to cure the resin; wherein each sub-preform of the plurality of sub-preforms comprises a stack of fiber-containing layers, said fiber-containing layers Petition 870250092085, dated 08 / 10 / 2025, p. 10 / 39 4 / 24 including: - one or more layers extending the entire length and width of the sub-preform, - a first layer of tape extending longitudinally along a first longitudinal side and the entire length of the sub-preform, - a second layer of tape arranged parallel to and spaced from the first layer of tape, the second layer of tape extending along a second longitudinal side and the entire length of the sub-preform, - a plurality of third layers of tape extending transversely to the longitudinal direction of the sub-preform, said plurality of third layers of tape arranged in parallel and spaced from each other; and wherein each of the first layer of tape and the second layer of tape comprises continuous unidirectional fibers aligned with the longitudinal direction of the sub-preform, and each of the multiple layers of third tape comprises continuous unidirectional fibers aligned with the transverse direction of the sub-preform.

[010] By means of the method described herein, the drag reduction device can be produced in a single body with the desired shape and size, without requiring the assembly of different parts, as used in the previously known SMC-based technique. In other words, the method described herein relies on the modularization of the material used to produce the drag reduction device, more specifically the sub-preforms, instead of the modularization of different parts produced to be assembled into the drag reduction device. This also avoids the need for a metal support structure that might be required to assemble the different parts produced and provide sufficient mechanical properties. The omission of the metal support structure reduces weight and also provides more space on board the vehicle to accommodate it. Petition 870250092085, dated 08 / 10 / 2025, page 11 / 39 5 / 24 other components, if desired.

[011] Furthermore, using the sub-preforms above, it is possible to obtain the desired mechanical properties of the drag reduction device. A drag reduction device on a heavy vehicle may be subject to considerable forces resulting from airflow, vibrations, and / or uneven road conditions. By means of the method described herein, the resulting drag reduction device will comprise reinforcement zones extending along the longitudinal sides of the drag reduction device, as well as reinforcement zones extending transversely to the longitudinal sides of the drag reduction device. These reinforcement zones ensure that the drag reduction device has sufficient mechanical properties to meet the most critical loads on the relevant parts of the drag reduction device without having to considerably increase the thickness of the device.When the drag reduction device is mounted on the side of a heavy vehicle, the reinforcement zones mentioned above will extend substantially in a vertical plane of the vehicle.

[012] The method described here is particularly advantageous for the production of a drag reduction device in the case of a side skirt or a side air deflector. These are drag reduction devices for heavy vehicles that typically have a considerable longitudinal extension, such as at least 1.5 meters and, in certain cases, up to 4 meters or more, and which may be subjected to considerable loads during vehicle operation.

[013] Each of the multiple third layers of tape can, according to a preferred alternative, extend between the first and second longitudinal sides of the sub-preform. This further improves the mechanical strength of the drag-reducing device.

[014] One or more layers that extend the entire length and Petition 870250092085, dated 08 / 10 / 2025, page 12 / 39 The 6 / 24 width of the sub-preform may comprise a fourth layer comprising unidirectional fibers oriented at an angle of +30° to +60° relative to the longitudinal direction of the sub-preform, and a fifth layer comprising unidirectional fibers oriented at an angle of -30° to -60° relative to the longitudinal direction of the sub-preform. This further improves the mechanical strength of the drag reduction device.

[015] Each sub-preform of the plurality of sub-preforms can suitably be a pre-consolidated sub-preform. In this way, the handling of the sub-preforms can be facilitated, which in turn facilitates the production of the drag reduction device and improves its quality.

[016] Subpreforms can be produced by automated tape overlapping. This has the advantage of precise manufacturing of the subpreforms, which increases their quality, as well as the resulting drag reduction device. More specifically, fiber orientation can be controlled more precisely. In addition, automated tape overlapping has the advantage of minimizing waste.

[017] The step of supplying a mold adapted to the geometric configuration of the drag reduction device to be produced (i.e., step a) may involve assembling a plurality of modular mold sections. In this way, the method described here can also use the modularization strategy for mold supply, which avoids the need to supply a separate mold for each possible size and configuration of the drag reduction device. This further reduces manufacturing costs when it is necessary to offer a wide variety of different sizes and configurations of drag reduction devices.

[018] Each of the various modular mold sections may have a mold surface corresponding to the geometric configuration of a portion Petition 870250092085, dated 08 / 10 / 2025, page 13 / 39 7 / 24 predefined longitudinal dimension of the drag reduction device to be produced.

[019] In addition, the present disclosure provides a drag reduction device for a heavy land vehicle, such as a side skirt or a side air deflector. The drag reduction device has a longitudinal axis and two opposing longitudinal sides and is made of a fiber-reinforced material. The drag reduction device comprises: - a first reinforcement zone, extending along a first longitudinal side of the two opposite longitudinal sides, the first reinforcement zone comprising continuous unidirectional fibers aligned parallel to the longitudinal axis of the drag reduction device, - a second reinforcement zone, extending along a second longitudinal side of the two opposite longitudinal sides and being spaced from the first reinforcement zone, said second reinforcement zone comprising continuous unidirectional fibers aligned parallel to the longitudinal axis of the drag reduction device, - a plurality of third reinforcement zones, spaced from each other along the longitudinal axis of the drag reduction device, each comprising continuous unidirectional fibers aligned transversely to the longitudinal axis of the drag reduction device.

[020] In view of the different reinforcement zones, the drag reduction device according to this disclosure does not require a metal support structure. In this way, the drag reduction device according to this disclosure allows a reduced drag coefficient of a vehicle with minimal added weight and thus reduces the vehicle's energy consumption. Furthermore, the drag reduction device does not suffer from the recycling problems of previously known SMC drag reduction devices. Petition 870250092085, dated 08 / 10 / 2025, p. 14 / 39 8 / 24

[021] The drag reduction device according to the present disclosure may suitably have a longitudinal extension of at least 1.5 meters. In other words, the drag reduction device may be a large drag reduction device for a heavy vehicle.

[022] This disclosure also provides a vehicle comprising the drag reduction device described above. The vehicle may be a heavy land vehicle, such as a truck or a trailer. BRIEF DESCRIPTION OF THE DRAWINGS

[023] Fig. 1 illustrates a side view of an example of a heavy land vehicle,

[024] Fig. 2 schematically illustrates a side view of a prior art side skirt for a heavy vehicle,

[025] Fig. 3 schematically illustrates a top view of a first exemplary embodiment of a sub-preform that can be used in the method described herein to produce a drag reduction device for a heavy vehicle,

[026] Fig. 4 schematically illustrates a cross-sectional view of a second exemplary embodiment of a sub-preform that can be used in the method described herein to produce a drag reduction device for a heavy vehicle,

[027] Fig. 5 represents a flowchart that schematically illustrates an exemplary embodiment of the method described herein for producing a drag reduction device for a heavy vehicle,

[028] Fig. 6 schematically illustrates an exploded top view of a female part of a mold comprising a plurality of modular mold sections,

[029] Fig. 7 schematically illustrates a top view of an example Petition 870250092085, dated 08 / 10 / 2025, p. 15 / 39 9 / 24 of how a plurality of sub-preforms can be arranged in a mold according to the method described herein, and

[030] Fig. 8 schematically illustrates a side view of an exemplary embodiment of the drag reduction device according to this disclosure. DETAILED DESCRIPTION

[031] The invention will be described in more detail below with reference to the exemplary embodiments and accompanying figures. The invention, however, is not limited to the exemplary embodiments discussed and / or shown in the figures, but may vary within the scope of the appended claims. Furthermore, the figures should not be considered drawn to scale, as some features may be exaggerated to illustrate the invention or features thereof more clearly.

[032] The term preform is used here to describe an arrangement of stacked layers containing fibers that may or may not be impregnated with resin, such as a thermoplastic resin. The term sub-preform is used here to describe a preform that is too small to produce the intended device. In other words, the term sub-preform is used here to illustrate that the size of such a preform is smaller than the size of the drag reduction device to be produced, so that a plurality of sub-preforms are needed to achieve the intended size and configuration of the drag reduction device.

[033] Furthermore, in the present disclosure a distinction is made between a layer and a tape layer. A layer is a substantially two-dimensional component of arbitrary extent in the various directions of a two-dimensional plane. In contrast, a tape layer is a substantially two-dimensional layer that has a considerably greater extent. Petition 870250092085, dated 08 / 10 / 2025, page 16 / 39 10 / 24 in the first direction of a two-dimensional plane than in the second direction of the two-dimensional plane, with the second direction being perpendicular to the first direction.

[034] This disclosure provides a method for producing a drag reduction device, comprising or consisting of continuous fiber reinforced plastics (CoFRP), for a heavy vehicle. The method described herein was developed primarily for producing a side skirt, or a side air deflector (also known as a cab side air deflector), for a wheeled heavy land vehicle. However, the method described herein can also be used to produce other drag reduction devices for heavy land vehicles, in particular larger drag reduction devices such as rear air deflectors (sometimes also called boat tails) or roof air deflectors.

[035] The method for producing a drag reduction device for a heavy vehicle according to the present disclosure comprises the following steps: (a) provide a mold adapted to the geometric configuration of the drag reduction device to be produced, (b) arrange a plurality of sub-preforms in said mold so that the sub-preforms are arranged side by side or in a partially overlapping arrangement, with a longitudinal direction of each of the plurality of sub-preforms corresponding to a longitudinal direction of the drag reduction device to be produced, (c) provide a resin, either by resin application or resin infiltration, to the plurality of sub-preforms arranged in the mold, unless the plurality of sub-preforms is already fully impregnated with said resin, and (d) heat treatment to cure the resin. Petition 870250092085, dated 08 / 10 / 2025, p. 17 / 39 11 / 24

[036] It should be noted here that the mold normally comprises a female part and a male part. The sub-preforms are normally placed in the female part of the mold. After that, the male part of the mold can be placed on top of the female part of the mold.

[037] Sub-preforms are normally flat sub-preforms and therefore can be described as two-dimensional. To obtain the desired three-dimensional shape of the drag reduction device, the method may further comprise a step of forming the sub-preforms into the desired three-dimensional shape using the mold. Said forming step may be performed before or during step (d). According to some embodiments, said forming step is performed after step (b) but before step (c). The forming step may comprise pressing the female part of the mold and the male part of the mold together.

[038] The method described herein may preferably be a thermoforming process. In this case, flat subpreforms may be produced by automated tape overlapping and subsequently subjected to preconsolidation. In automated tape overlapping, several strips of unidirectional tapes (also known as UD tapes) are placed adjacent to each other to form complete layers of a subpreform and may also be used to place layers of individual tapes where desired. Unidirectional tapes are composed of unidirectionally aligned reinforcing fibers embedded in a thermoplastic matrix. Preconsolidation may comprise heating the tape-layered subpreforms above the polymer melting temperature, followed by cooling while applying pressure.To produce the desired final three-dimensional shape of the drag reduction device, the pre-consolidated sub-preforms, after being arranged in the mold as described above, are subjected to heat stamping. Heat stamping is an example of the forming step described above. Petition 870250092085, dated 08 / 10 / 2025, page 18 / 39 12 / 24

[039] According to another alternative, the method described here may be a thermoforming process, but in which automated tape overlapping is not used to produce the subpreforms. Instead, at least one organosheet and unidirectional tapes are used to produce the subpreforms. Organosheets are fully impregnated sheets comprising a woven fiber architecture and which can often be pre-consolidated.

[040] Alternatively, the method described herein may be a resin transfer molding process. In this case, the flat sub-preforms are pre-consolidated and subsequently subjected to pre-forming in the desired three-dimensional geometric configuration, followed by resin infiltration and curing. Pre-molding is normally performed in a mold different from the one in which resin infiltration and curing are performed. If the method described herein is a resin transfer molding process, step (a) of the method described herein may comprise the provision of a molding mold adapted to the geometric configuration of the drag reduction device to be produced, and step (b) may further comprise the joining of the plurality of sub-preforms to one another.Furthermore, the method in such a case comprises molding the plurality of sub-preforms into a network-shaped preform in the molding mold and transferring the network-shaped preform to a resin transfer molding mold. Steps (c) and (d) are then performed in the resin transfer molding mold. Alternatively, if the method is a resin transfer molding process, step (a) comprises providing a resin transfer molding mold adapted to the geometric configuration of the drag reduction device to be produced and the method comprises a further step of liquid molding of each individual preform in a molding mold corresponding to the relevant (longitudinal) portion of the drag reduction device to be produced. Furthermore, a. Petition 870250092085, dated 08 / 10 / 2025, page 19 / 39 13 / 24 step (b) involves arranging the plurality of sub-preforms, which were molded in a network, in the resin transfer mold. Steps (c) and (d) are then performed in the resin transfer mold.

[041] According to one alternative, the process described herein may be a wet compression molding process. In this case, the resin is applied to the sub-preforms before they are placed in the mold in step (b) (in other words, step (c) is omitted). Furthermore, the method comprises molding, pressing and heat treatment to cure the resin within the mold.

[042] Each sub-preform of the plurality of sub-preforms comprises a stack of layers containing fibers comprising: - one or more layers extending the entire length and width of the sub-preform, - a first layer of tape extending longitudinally along a first longitudinal side and the entire length of the sub-preform, - a second layer of tape arranged parallel to and spaced from the first layer of tape, the second layer of tape extending along a second longitudinal side and the entire length of the sub-preform, and - a plurality of third layers of tape extending transversely to the longitudinal direction of the sub-preform, said plurality of third layers of tape arranged in parallel and spaced from each other.

[043] Each of the first and second tape layers mentioned above comprises continuous unidirectional fibers aligned with the longitudinal direction of the sub-preform. In addition, each of the multiple third tape layers comprises continuous unidirectional fibers aligned with the transverse direction of the sub-preform. Preferably, each of the multiple third tape layers extends between the first and second longitudinal sides of the sub-preform. Petition 870250092085, dated 08 / 10 / 2025, page 20 / 39 14 / 24

[044] Continuous fibers are high-performance fibers characterized by having a very high length-to-diameter ratio. When the fibers are aligned, they provide maximum strength, but only along the direction of alignment. The composite is considerably weaker in other directions and is therefore highly anisotropic. Therefore, the sub-preforms used according to the present method comprise both the first and second tape layers, as well as the plurality of third tape layers, as described above.

[045] At least one layer mentioned above, extending throughout the length and width of the sub-preform, may, according to various embodiments, comprise a fourth layer comprising unidirectional fibers oriented at an angle of +30° to +60° with respect to the longitudinal direction of the sub-preform, and a fifth layer comprising unidirectional fibers oriented at an angle of -30° to -60° with respect to the longitudinal direction of the sub-preform. Alternatively, or additionally, the at least one layer extending throughout the length and width of the sub-preform may comprise a woven structure of continuous fibers.

[046] As mentioned earlier, the present method comprises a step of supplying a mold adapted to the geometric configuration of the drag reduction device to be produced. The mold may suitably consist of a plurality of modular mold sections assembled together depending on the desired geometric configuration of the drag reduction device to be produced. In this way, tooling costs are reduced if it is intended to produce a wide variety of different configurations of the drag reduction device. Thus, the step of supplying a mold adapted to the geometric configuration of the drag reduction device to be produced may comprise the assembly of a plurality of Petition 870250092085, dated 08 / 10 / 2025, page 21 / 39 15 / 24 modular mold sections. Each mold section of the modular mold sections may suitably have a mold surface corresponding to the geometric configuration of a predefined longitudinal portion of the drag reduction device to be produced. In other words, the mold provided may suitably comprise a plurality of modular mold sections arranged successively along the longitudinal extent of the drag reduction device to be produced.

[047] This disclosure further provides a drag reduction device for a heavy land vehicle, such as a side skirt or a side air deflector. The drag reduction device has a longitudinal axis and two opposing longitudinal sides and is made of a fiber-reinforced material. More specifically, the drag reduction device is made of continuous fiber-reinforced plastic. The drag reduction device comprises: - a first reinforcement zone, extending along a first longitudinal side of the two opposite longitudinal sides, the first reinforcement zone comprising continuous unidirectional fibers aligned parallel to the longitudinal axis of the drag reduction device, - a second reinforcement zone, extending along a second longitudinal side of the two opposite longitudinal sides and being spaced from the first reinforcement zone, said second reinforcement zone comprising continuous unidirectional fibers aligned parallel to the longitudinal axis of the drag reduction device, - a plurality of third reinforcement zones, spaced from each other along the longitudinal axis of the drag reduction device, each comprising continuous unidirectional fibers aligned transversely to the longitudinal axis of the drag reduction device.

[048] The drag reduction device is preferably a Petition 870250092085, dated 08 / 10 / 2025, p. 22 / 39 16 / 24 large drag reduction device and may therefore have a longitudinal extension of at least 1.5 meters. According to some embodiments, the drag reduction device may have a longitudinal extension of at least 2 meters, or even at least 3 meters. The longitudinal extension of the drag reduction device may, for example, be less than 5 meters or less than 4.5 meters.

[049] The drag reduction device according to the present disclosure is preferably a one-piece drag reduction device, meaning that it does not consist of a plurality of different pre-produced components assembled together to obtain a desired length of the drag reduction device.

[050] Figure 1 illustrates a side view of an example of a heavy land vehicle 1, here illustrated as a tow truck. Vehicle 1 has a front side 2 and a rear side 3, between which extend the side sides of the vehicle. Vehicle 1 comprises a plurality of ground contact wheels 4.

[051] The illustrated vehicle 1 comprises a first side skirt 10 arranged to extend longitudinally along one side of the vehicle. It should be noted here that the vehicle may normally also comprise a second side skirt arranged along the other side of the vehicle. A side skirt is a component designed to reduce or control the airflow entering the chassis region from the side of the vehicle. The airflow passing under a vehicle transmits a drag force when it hits and flows around chassis components attached to or forming part of the underside of the vehicle, and a side skirt is therefore able to considerably reduce this drag force.

[052] Similarly, a drag force can be created by the airflow in the space behind the rear wall of the cabin. This can be considerably Petition 870250092085, dated 08 / 10 / 2025, page 23 / 39 17 / 24 reduced by an air deflector on the ceiling and side air deflectors, both configured to guide the airflow so as not to enter the said space.

[053] Therefore, the illustrated vehicle 1 further comprises a side air deflector 11, which can be mounted on the rear of the driver's cab 5 of the vehicle. The side air deflector 11 is arranged so that it extends longitudinally in the vertical direction of the vehicle 1. The illustrated vehicle 1 also comprises a roof air deflector 12. The roof air deflector 12 can be mounted on the driver's cab 5. In contrast to the side skirt 10 and the side air deflector 11, the roof air deflector 12 extends substantially across the entire width of the vehicle 1.

[054] The method described here will be exemplified herein with reference to the production of a side skirt for the sake of clarity. Meanwhile, the method is not limited to the production of a side skirt, but can also be used to produce other drag-reducing devices for a heavy vehicle, as discussed previously.

[055] Figure 2 schematically illustrates an example of a side skirt 10' of the prior art for a heavy vehicle, such as vehicle 1 shown in Figure 1. The side skirt 10' is shown viewed from a side intended to face the vehicle chassis. The side skirt 10' comprises a first end portion 21, a first center portion 22, a second center portion 23, and a second end portion 24 arranged consecutively along the longitudinal extent LD of the side skirt 10. The different portions 21-24 are produced separately and subsequently assembled onto a metal support structure 25 to provide a side skirt assembly. The metal support structure 25 is configured to provide sufficient mechanical properties in both the longitudinal and transverse directions of the side skirt assembly. The different portions 21-24 can be made of SMC and constitute Petition 870250092085, dated 08 / 10 / 2025, page 24 / 39 18 / 24 modularized components. This means that if a longer longitudinal extension side skirt is desired, an additional central portion (such as portions 22 or 23) can be added.

[056] In contrast to the side skirt shown in Figure 2, a side skirt produced according to the method described here need not consist of a plurality of longitudinal portions produced separately and assembled together. Instead, a side skirt (or any other drag-reducing device for a heavy vehicle, as described here) can be made of a single body consisting of continuous fiber-reinforced plastic. Furthermore, by the method described here, the drag-reducing device need not comprise any metallic support structure. This, in turn, results in a reduction in weight and, if desired, more available space on board the vehicle to accommodate other components. This is a result of both the material selection and the production method selection.More specifically, the method described here for producing a drag-reducing device, such as a side skirt, utilizes a plurality of sub-preforms of a specific configuration, ensuring that the desired mechanical strength in various directions of the drag-reducing device is achieved. The use of a plurality of sub-preforms in the production of the drag-reducing device allows for modularization. For example, the plurality of sub-preforms may have different longitudinal extensions, different numbers of third layers of tape, and / or different numbers and / or types of layers extending throughout the length and width of the sub-preform. According to the method described here, the plurality of sub-preforms are arranged side-by-side or in a partially overlapping arrangement.Thus, the first and second tape layers of a first sub-preform are extended by the first and second tape layers of a second sub-preform adjacent to the first sub-preform, which, in turn, results in zones of... Petition 870250092085, dated 08 / 10 / 2025, p. 25 / 39 19 / 24 reinforcement extending longitudinally along the sides of the resulting drag reduction device.

[057] Figure 3 schematically illustrates a top view of an exemplary embodiment of a sub-preform 30 that can be used in the method described herein to produce a drag reduction device for a heavy vehicle. The illustrated sub-preform is a substantially flat sub-preform 30 with length L (i.e., extension in the longitudinal direction) and width w. The width w can essentially correspond to the width of the drag reduction device to be produced. However, the length L of the sub-preform 30 is considerably less than the longitudinal extension of the drag reduction device to be produced. The sub-preform comprises a first longitudinal side 31 and a second opposite longitudinal side 32. The sub-preform may have a rectangular area, as shown in the figure. Alternatively, the sub-preform may have the area of ​​a parallelogram.If the sub-preform is to be placed in a longitudinal end portion of the drag reduction device to be produced, other geometric shapes are also plausible.

[058] Sub-preform 30 comprises a stack of layers containing fibers. More specifically, sub-preform 30 comprises at least one layer 33 extending the entire length L and width w of the sub-preform. In other words, at least one layer 33 extends the entire area of ​​sub-preform 30. At least one layer 33 may, for example, be formed by a plurality of tape layers arranged adjacent to each other so as to form the layer together, although the present disclosure is not limited to at least one layer 33 being formed by tape layers. For example, at least one layer 33 may alternatively comprise a woven structure comprising continuous fibers. The sub-preform further comprises a first tape layer 36 extending in the longitudinal direction of sub-preform 30 to Petition 870250092085, dated 08 / 10 / 2025, p. 26 / 39 20 / 24 along the first longitudinal side 31 of the sub-preform. The first layer of tape 36 extends the entire length L and comprises continuous unidirectional fibers aligned with the longitudinal direction of the sub-preform. Furthermore, the sub-preform 30 comprises a second layer of tape 37 arranged parallel to and spaced from the first layer of tape 36. The second layer of tape 37 extends along the second longitudinal side 32 of the sub-preform 30. Like the first layer of tape 36, the second layer of tape 37 comprises continuous unidirectional fibers aligned with the longitudinal direction of the sub-preform.

[059] The sub-preform 30 further comprises a plurality of third layers of tape 38 extending transversely to the longitudinal direction of the sub-preform. It should be noted that, although the figure illustrates four of these tape layers, the number of third layers of tape may be 2, 3 or more than 4, without departing from the present disclosure. The number of third layers of tape may, for example, depend on the length of the sub-preform 30 and / or the strength requirements of the drag reduction device to be produced. The third layers of tape 38 are arranged in parallel and spaced from each other.

[060] Furthermore, each of the multiple third layers of tape 38 comprises continuous unidirectional fibers aligned with the transverse direction of the sub-preform, i.e., aligned in the width direction of the sub-preform 30.

[061] Figure 4 schematically illustrates a cross-sectional view of a second exemplary embodiment of a sub-preform 30 according to the present disclosure, taken close to and parallel with a first longitudinal side of the sub-preform 30. The sub-preform according to the second exemplary embodiment comprises, in addition to a first layer of tape 36 and a second layer of tape 37 (not visible in the figure) extending along a respective longitudinal side of the sub-preform, a plurality of third layers of tape extending transversely to the first and second layers. Petition 870250092085, dated 08 / 10 / 2025, p. 27 / 39 21 / 24 of tape 36, 37, a fourth layer 34 and a fifth layer 35. Each of the fourth and fifth layers 34, 35 extends the entire length and width of the sub-preform, i.e., the entire area of ​​the sub-preform. The fourth layer 34 comprises continuous unidirectional fibers oriented at an angle of +30° to +60° relative to the longitudinal direction of the sub-preform. The fifth layer 35 comprises unidirectional fibers oriented at an angle of -30° to -60° relative to the longitudinal direction of the sub-preform. The fourth and fifth layers 34, 35 can be suitably formed by automated tape layering to achieve the desired fiber orientation of the respective layers.

[062] Figure 5 represents a flowchart that schematically illustrates an exemplary embodiment of the method described herein for producing a drag reduction device, such as a side skirt or a side air deflector. The method comprises a step S101 of supplying a mold adapted to the geometric configuration of the drag reduction device to be produced. The method further comprises a step S102 of arranging a plurality of sub-forms in said mold so that the sub-forms are arranged side by side or in a partially overlapping arrangement, with a longitudinal direction of each of the plurality of sub-forms corresponding to a longitudinal direction of the drag reduction device to be produced. The method may also comprise a step S103 of supplying a resin, either by resin application or

[063] resin infiltration, to the plurality of sub-preforms arranged in the mold. If the sub-preforms are already fully impregnated with resin, step S103 can be omitted. The subsequent method comprises a heat treatment step S104 to cure the resin. In this way, the drag reduction device is obtained.

[064] Figure 6 schematically illustrates an exploded view of a Petition 870250092085, dated 08 / 10 / 2025, page 28 / 39 22 / 24 mold 40 which can be used in the method described herein to produce a drag reduction device. For clarity and ease of illustration, only the female part of the mold is shown. However, it should be noted that the mold normally also comprises a corresponding male mold part. Mold 40 comprises a plurality of modular mold sections 41, 42, 43, 44 which are assembled to form the mold. It should be noted that although only the female part of each modular mold section is shown in the figure, each modular mold section 41, 42, 43, 44 also comprises a corresponding male part. Each of the modular mold sections has a mold surface corresponding to the geometric configuration of a predefined longitudinal portion of the drag reduction device to be produced, which in the present example is a side skirt for a heavy vehicle.More specifically, the plurality of mold sections comprises a first mold section 41 having a mold surface 41a corresponding to a first longitudinal end portion of the side skirt. The plurality of mold sections further comprises a second mold section 42 and a third mold section, each having respective mold surfaces 42a, 43a, corresponding to a longitudinal portion present between the opposite longitudinal end portions of the side skirt to be produced. In addition, the plurality of mold sections comprises a fourth mold section 44 having a mold surface 44a corresponding to a second longitudinal end portion (opposite the first longitudinal end portion) of the side skirt.

[065] To adapt to a desired length and geometric configuration of the drag reduction device to be produced, one of the modular mold sections 42 and 43 may be omitted, replaced by an alternative modular mold section and / or one or more additional modular mold sections may Petition 870250092085, dated 08 / 10 / 2025, pp. 29 / 39 23 / 24 can be added. The modular mold sections can be assembled side-by-side along the longitudinal direction of the drag reduction device to be produced.

[066] The use of modular mold sections to accommodate the variety of sizes and different configurations of drag reduction devices to be produced reduces tooling costs and therefore also overall production costs.

[067] Figure 7 schematically illustrates a top view of an example of how a plurality of individual sub-preforms 30 can be arranged in a mold, such as the mold 40 shown in Figure 6. In the figure, four sub-preforms are used, numbered 30-1 to 30-4 for the purpose of distinguishing them from each other. The sub-preforms are in the example arranged in a partially overlapping arrangement, the overlapping regions marked with the reference number 39. Furthermore, the sub-preforms are arranged so that their longitudinal directions correspond to the longitudinal direction of the drag reduction to be produced.The fact that the sub-preforms are arranged so as to partially overlap ensures sufficient mechanical strength in the longitudinal direction of the drag reduction device, since there will be no interruption between the first and second layers of tape of one sub-preform and the first and second layers of tape of an adjacent sub-preform when the production of the drag reduction device is completed.

[068] According to an alternative to an overlapping arrangement, the plurality of sub-preforms can be arranged side by side, as seen in their longitudinal direction. If this is the case, one or more additional layers containing fibers should preferably be arranged above or below the plurality of sub-preforms in order to guarantee the desired mechanical strength in the longitudinal direction of the resulting drag-reducing device. These Petition 870250092085, dated 08 / 10 / 2025, pp. 30 / 39 24 / 24 additional layers containing fibers should be provided in the mold before the heat treatment step to cure the resin. However, it should be noted that a partially overlapping arrangement of the plurality of sub-preforms is preferable.

[069] After the plurality of sub-preforms have been arranged in the mold, parts of them that may possibly extend beyond the surface of the mold can be removed by trimming according to conventional techniques.

[070] Figure 8 schematically illustrates a side view of an exemplary embodiment of the drag reduction device according to the present disclosure, more specifically a side skirt 10 for a heavy vehicle. The illustrated side skirt 10 can be produced according to the method described above for producing a drag reduction device. The side skirt has a longitudinal direction LD, as shown in the figure.

[071] The side skirt 10 comprises a first reinforcement zone 53, which extends along a first longitudinal side 51 of the side skirt 10. Said first reinforcement zone 53 comprises unidirectional continuous fibers aligned parallel to a longitudinal axis A of the side skirt 10. The side skirt 10 further comprises a second reinforcement zone 54 which extends along a second longitudinal 52 of the side skirt. Like the first reinforcement zone 53, the second reinforcement zone comprises unidirectional continuous fibers aligned parallel to a longitudinal axis A of the side skirt 10. In addition, the side skirt 10 comprises a plurality of third reinforcement zones 55, spaced from each other along the longitudinal axis A of the side skirt 10. In the figure, eight reinforcement zones 55 are illustrated. Each of the third reinforcement zones 55 comprises unidirectional continuous fibers aligned transversely to the longitudinal axis A of the side skirt. Petition 870250092085, dated 08 / 10 / 2025, pp. 31 / 39

Claims

1 / 4 CLAIMS 1. Method of producing a drag reduction device (10, 11, 12) for a heavy vehicle (1), the method CHARACTERIZED in that it comprises the following steps: (a) providing (S101) a mold (40) adapted to the geometric configuration of the drag reduction device (10, 11, 12) to be produced, (b) arranging (S102) a plurality of sub-preforms (30) in said mold (40) such that the sub-preforms (30) are arranged side by side or in a partially overlapping arrangement, with a longitudinal direction of each of the plurality of sub-preforms (30) corresponding to a longitudinal direction (LD) of the drag reduction device (10, 11, 12) to be produced, (c) providing (S103) a resin, either by resin application or resin infiltration, to the plurality of sub-preforms (30) arranged in the mold (40), unless the plurality of sub-preforms (30) is already fully impregnated with said resin,and (d) heat treatment (S104) to cure the resin; wherein each sub-preform (30) of the plurality of sub-preforms (30) comprises a stack of fiber-containing layers, said fiber-containing layers comprising: - one or more layers (33, 34, 35) extending over the entire length (w) and width (L) of the sub-preform, - a first layer of tape (36) extending in the longitudinal direction of the sub-preform (30) along a first longitudinal side (31) and over the entire length (L) of the sub-preform (30), - a second layer of tape (37) arranged parallel to and spaced from the first layer of tape (36), the second layer of tape (37) extending along a second longitudinal side (32) and over the entire length (L) of the sub-preform. Petition 870250092085, dated 08 / 10 / 2025, page. 32 / 39 2 / 4 preform (30), - a plurality of third layers of tape (38) extending transversely to the longitudinal direction of the sub-preform,said plurality of third layers of tape (30) arranged in parallel and spaced from each other; and wherein each of the first layer of tape (36) and of the second layer of tape (37) comprises continuous unidirectional fibers aligned with the longitudinal direction of the sub-preform (30), and each of the plurality of third layers of tape (38) comprises continuous unidirectional fibers aligned with the transverse direction of the sub-preform (30).

2. Method according to claim 1, CHARACTERIZED in that the drag reduction device is a side skirt (10) or a side air deflector (11).

3. Method, according to any one of claims 1 or 2, CHARACTERIZED in that each of the plurality of third layers of tape (38) extends between the first and second longitudinal sides of the sub-preform (30).

4. Method, according to any of the preceding claims, CHARACTERIZED in that one or more layers extending throughout the length (L) and width (w) of the sub-preform (30) comprise: a fourth layer (34) comprising unidirectional fibers oriented at an angle of +30° to +60° with respect to the longitudinal direction of the sub-preform (30), and a fifth layer (35) comprising unidirectional fibers oriented at an angle of -30° to -60° with respect to the longitudinal direction of the sub-preform (30). Petition 870250092085, dated 08 / 10 / 2025, p. 33 / 39 3 / 4 5. Method, according to any of the preceding claims, CHARACTERIZED in that each sub-pre-form (30) of the plurality of sub-pre-forms is a pre-consolidated sub-pre-form.

6. Method, according to any of the preceding claims, CHARACTERIZED in that it further comprises the production of each of the plurality of sub-preforms (30) by automated tape overlapping.

7. Method, according to any of the preceding claims, CHARACTERIZED in that step (a) of providing a mold (40) adapted to the geometric configuration of the drag reduction device to be produced comprises the assembly of a plurality of modular mold sections (41, 42, 43, 44).

8. Method according to claim 7, CHARACTERIZED in that each of the various modular mold sections (41, 42, 43, 44) has a mold surface (41a, 42a, 43a, 44a) corresponding to the geometric configuration of a predefined longitudinal portion of the drag reduction device (10, 11, 12) to be produced.

9. Drag reduction device (10, 11, 12) for a heavy land vehicle (1), the drag reduction device (10, 11, 12) having a longitudinal axis (A) and two opposite longitudinal sides and being made of a fiber-reinforced material, CHARACTERIZED in that the drag reduction device (10, 11, 12) comprises: - a first reinforcement zone (53), extending along a first longitudinal side (51) of the two opposite longitudinal sides, the first reinforcement zone (53) comprising continuous unidirectional fibers aligned parallel to the longitudinal axis (A) of the drag reduction device (10, 11, 12), - a second reinforcement zone (54), extending along a Petition 870250092085, dated 08 / 10 / 2025, page.34 / 39 4 / 4 second longitudinal side (52) of the two opposite longitudinal sides and being spaced from the first reinforcement zone (53), wherein said second reinforcement zone (54) comprises continuous unidirectional fibers aligned parallel to the longitudinal axis (A) of the drag reduction device (10,11,12), - a plurality of third reinforcement zones (55), spaced from each other along the longitudinal axis (A) of the drag reduction device (10, 11, 12), each comprising continuous unidirectional fibers aligned transversely to the longitudinal axis (A) of the drag reduction device (10, 11, 12).

10. Drag reduction device, according to claim 9, CHARACTERIZED in that the drag reduction device is a side skirt (10) or a side air deflector (11) for a heavy vehicle.

11. Drag reduction device, according to any one of claims 9 to 10, CHARACTERIZED in that it has a longitudinal extension of at least 1.5 meters.

12. Vehicle (1), CHARACTERIZED in that it comprises the drag reduction device (10, 11, 12), according to any one of claims 9 to 11. Petition 870250092085, dated 08 / 10 / 2025, pp. 35 / 39

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