LOWER BUMPER STIFFENER AND AUTOMOTIVE VEHICLE THEREOF

The present invention is directed to a new lower bumper stiffener comprising a front section, a base plate and longitudinal ribs, as well as an automotive vehicle comprising the lower bumper stiffener.

Typical bumper systems for automotive vehicles extend across the front and rear of the vehicle and have long been designed primarily as an absorber for impact forces generated during collisions with other vehicles and/or fixed objects. However, in many collisions between moving vehicles and pedestrians, the bumper system typically makes contact with the lower leg of the pedestrian, while the pedestrian's foot tends to remain standing on the ground. If the automotive vehicle moves further, the bumper typically overrides the lower pedestrian's leg which may result in potentially severe knee injuries. It has thus become more and more important to reduce the risk of injuries during an impact between an automotive vehicle and a pedestrian. In this regard, lower bumper stiffener (abbreviation: LBS) have been developed in order to provide pedestrian lower leg protection when a running vehicle collides with the pedestrian and thus the lower pedestrian's leg is not bending under the vehicle. Such lower bumper stiffener locates typically behind the front bumper fascia, close to bottom of the front bumper fascia, and extends across substantially the full width of the bumper fascia but with a small gap to the bumper fascia. It can be connected to the bumper fascia via bolt or plug at one or more points, or not. At present lower bumper stiffeners are typically made from glass-fiber reinforced polyamide or metal having a shape of a beam. However, such lower bumper stiffener made from metal, although very strong in stiffness, can be very heavy and thus are not preferred by the automobile manufacturer. Furthermore, these lower bumper stiffeners are limited in geometry and shape. In contrast thereto, lower bumper stiffeners made from glass-fiber reinforced polyamide typically provide an unstable stiffness depending on environmental conditions such as humidity due to the water absorption characteristics of the polyamide. Furthermore, the lower bumper stiffeners made from glass-fiber reinforced polyamide are not a cost effective solution for lower-leg protection relative to polypropylene.

Thus, there is still a demand for lower bumper stiffener having a sufficient stiffness, good legform pedestrian protection, being cost-efficient and reduced in weight.

Thus, the object of the present invention is to provide a lower bumper stiffener having a sufficient stiffness and legform pedestrian protection and being reduced in weight. Furthermore, a cost-efficient lower bumper stiffener should be provided. The finding of the present invention is a lower bumper stiffener (1) comprising a front section (2), a base plate (6) and longitudinal ribs (8).

Accordingly, the present invention is directed to a lower bumper stiffener (1) comprising

a) a front section (2) comprising a front plate (3), a rear plate (4) and V- shaped corrugations (5) extending between the front plate (3) and the rear plate (4), wherein the rear plate (4) is located in parallel to the front plate a base plate (6) attached to the bottom of the front section (2) such that the front edge (7) of the base plate (6) joins the bottom of the front sections rear plate (4) essentially at right-angle, and

c) longitudinal ribs (8) extending in an impact direction and being attached to the upper surface of the base plate (6).

It has surprisingly been found that such a lower bumper stiffener has a sufficient and stable stiffness and excellent legform pedestrian protection, and is reduced in weight. Furthermore, the lower bumper stiffener can be produced at lower cost than the lower bumper stiffener made from glass-fiber reinforced polyamide.

Another aspect of the present invention is directed to an automotive vehicle comprising the lower bumper stiffener (1). According to one embodiment of the present invention, the front plate (3) and the rear plate (4) are arc-shaped. The arc-shape corresponds to the arc of front bumper fascia, behind which the lower bumper stiffener is assembled.

According to another embodiment of the present invention, the V-shaped

corrugations (5) consist of a plurality of V-shaped units (5a), preferably each V- shaped unit (5a) has a vertex angle "a" from 20° to 120°, preferably from 45° to 90° and most preferably from 60° to 90°.

According to yet another embodiment of the present invention, the height "h" of the front plate (3) and of the rear plate (4) is essentially equal to the height "h" of the V- shaped corrugations (5).

According to one embodiment of the present invention, the base plate (6) is essentially flat. According to another embodiment of the present invention, the front edge (7) of the base plate (6) is arc-shaped, preferably identical to the arc of the rear plate (4) of the front section (2). According to yet another embodiment of the present invention, the base plate (6) comprises a rear flange (9), vertical to upper surface of the base plate (6).

According to one embodiment of the present invention, the thickness of the rear flange (9) is essentially equal to the thickness "tl " of the base plate (6).

According to another embodiment of the present invention, the longitudinal ribs (8) stand essentially at right-angles from the base plate (6) and are moulded integrally from the same material thereon. According to yet another embodiment of the present invention, a) the height "h" of the longitudinal ribs (8) is essentially equal to the height "h" of the V-shaped corrugations (5), and/or b) the ratio of the height "h" of the longitudinal ribs (8) to the thickness "tl" of the base plate (6) (h/tl) is in the range from 2 to 5, preferably in the range from 3 to 5 and most preferably from 4 to 5, and/or c) the distance "d" between the longitudinal ribs (8) is essentially even, preferably the distance "d" between two adjacent longitudinal ribs (8) is from 10 to 60 mm, preferably from 20 to 50 mm, and most preferably from 20 to 30 mm.

According to one embodiment of the present invention, one end of the longitudinal ribs (8) is attached vertically to the rear plate (4) of the front section (2) and the other end of the longitudinal ribs (8) is attached vertically to the rear flange (9) of the base plate (6).

According to another embodiment of the present invention, the length of the longitudinal ribs (8) varies with location on the base plate (6), preferably the longitudinal rib (8) located at the central axle of the base plate (6) has the greatest length and the longitudinal rib (8) located at the lateral side of the base plate (6) has the smallest length. According to yet another embodiment of the present invention, the ratio of thickness "t2" of the longitudinal ribs (8) to thickness "tl " of the base plate (2) (t2/tl) is from 0.4 to 1.0, preferably from 0.5 to 0.8 and most preferably from 0.5 to 0.75.

According to one embodiment of the present invention, the lower bumper stiffener (1) is produced from a glass fiber-reinforced polypropylene.

In the following, it is referred to further details of the present invention and especially the single components of the lower bumper stiffener (1).

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings wherein the same elements are numbered alike and which are presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

Fig. 1 is a schematic three-dimensional top view of an embodiment of a lower bumper stiffener (1).

Fig. 2 is a schematic top view of an embodiment of the front section (2) of the lower bumper stiffener (1). Fig. 2a is an enlarged schematic cross-sectional view of an embodiment of a portion "C" of the front section (2) of the lower bumper stiffener (1 ), taken along the line D- D in Fig.2b. Fig. 2b is an enlarged schematic top view of an embodiment of a portion "C" of the front section (2) of the lower bumper stiffener (1).

Fig. 3 is a schematic top view of an embodiment of the base plate (6) of the lower bumper stiffener (1).

Fig. 3a is a schematic cross-sectional view of an embodiment of the base plate (6) of the lower bumper stiffener (1) taken along the line A-A of Fig. 3.

Fig. 4 is a schematic top view of an embodiment of the longitudinal ribs (8) of the lower bumper stiffener (1).

Fig. 4a is a schematic top view of an embodiment of single longitudinal ribs (8) of the lower bumper stiffener (1).

Component Reference number list

Lower bumper stiffener 1

Front section 2

Front plate 3

Rear plate 4

V-shaped corrugations 5

V-shaped unit 5a

Base plate 6

Front edge 7

Longitudinal ribs 8 Rear flange 9

Rear edge 10

DETAILED DESCRIPTION The present lower bumper stiffener (1) for automotive vehicles is a lightweight and cost-efficient lower- leg protector for vehicles (Fig. 1). Furthermore, the present lower bumper stiffener (1) for automotive vehicles has a sufficient stiffness and excellent legform pedestrian protection, preferably, the stiffness is stable at varying environmental conditions such as varying humidity.

Leg injuries are mainly caused by the impact of pedestrian's legs with stiffer portions of the vehicle bumper system. The present lower bumper stiffener (1) provides a solution to this problem, i.e., where the pedestrian's knee experiences high impact forces and high bending between the upper and bottom portion of the leg. The present lower bumper stiffener (1) can significantly reduce knee bending by pushing bottom portion of the leg backward, during a collision of the vehicle with the pedestrian leg.

The present lower bumper stiffener (1) is capable of meeting existing pedestrian impact regulations. For example, the present lower-bumper stiffener meets the requirements of the Flexible Pedestrian Legform Impactors (Flex-PLI). The Flex PLI (Flexible Pedestrian Legform Impactor) simulates the flexible nature of the human bone. It is fired from a linear guide into the bumper of a static vehicle at 40 kilometers per hour (km/hr or kmph) for the assessment of pedestrian lower leg and knee injuries.

The present lower bumper (1) stiffener can be prepared from any thermoplastic material or combination of thermoplastic material with another material (e.g., an elastomeric material and/or thermoset material), such as a filled thermoplastic polyolefin (TPO). Suitable thermoplastic materials are preferably selected from the group consisting of acrylic-styrene-acrylonitrile (ASA), acrylonitrile-butadiene- styrene (ABS), acrylonitrile-(ethylene-polypropylene diamine modified)-styrene (AES), polybutylene terephthalate (PBT), polycarbonate, polyphenylene ether resins, blends of polyphenylene ether/polyamide, polyamides, polyvinyl chloride PVC, high impact polystyrene (HIPS), polypropylene (PP), thermoplastic olefins (TPO) and reinforced (such as glass fiber reinforced) materials of the above resins. For example, the lower bumper stiffener (1) is produced from a glass fiber-reinforced polypropylene.

The lower bumper stiffener (1) of the present invention is preferably a moulded lower bumper stiffener (1), more preferably an injection moulded lower bumper stiffener (1). In one embodiment of the present invention, the lower bumper stiffener (1) is an injection moulded lower bumper stiffener (1) comprising at least up to 60.0 wt.-%, preferably at least 80.0 wt.-%, like 80.0 to 100.0 wt.-%, more preferably at least 95.0 wt.-%, like 95.0 to 100.0 wt.-%, and most preferably consisting of a glass fiber-reinforced polypropylene.

Preferably, the single components of the lower bumper stiffener (1), i.e. the front section (2), the base plate (6) and the longitudinal ribs (8) are prepared from the same material in a moulding process, preferably an injection moulding process. In order to obtain the lower bumper stiffener (1), the front section (2) and the longitudinal ribs (8) are preferably moulded integrally on the base plate (6) of the lower bumper stiffener (1). For example, the front section (2) is moulded integrally at right-angles on the base plate (6) with the rear plate (4) of the front section (2) joining front edge (7) of the base plate (6). Concurrently, the longitudinal ribs (8) are moulded integrally at right-angles on the base plate (6). Moulding or injection moulding processes and integrally moulding processes are within the skill of the art. A more complete understanding of the lower bumper stiffener (1) and its single components can be obtained by reference to the accompanying drawings. These drawings (also referred to herein as "Fig.") are merely schematic representations based on convenience and the ease of demonstrating the present invention, and are, therefore, not intended to indicate relative size and dimensions of the lower bumper stiffener (1) and its single components and/or to define or limit the scope of the exemplary embodiments. Although specific terms are used in the following description for the sake of clarity, these terms are intended to refer only to the particular structure of the embodiments selected for illustration in the drawings, and are not intended to define or limit the scope of the present disclosure. In the drawings and the following description below, it is to be understood that the same numeric designation refers to components having the same function.

Fig. 1 shows a schematic three-dimensional top view of an embodiment of such a lower bumper stiffener (1). It is one requirements of the present invention that the lower bumper stiffener (1) comprises a front section (2) comprising a front plate (3), a rear plate (4) and V-shaped corrugations (5) extending between the front plate (3) and the rear plate (4). Furthermore, the rear plate (4) of the front section (2) is located in parallel to the front plate (3) of the front section (2). It is further required that the lower bumper stiffener (1) comprises a base plate (6) attached to the bottom of the front section (2) such that the front edge (7) of the base plate (6) joins the bottom of the front sections rear plate (4) essentially at right-angle. In addition thereto, the lower bumper stiffener (1) comprises longitudinal ribs (8) extending in an impact direction and being attached to the upper surface of the base plate (6). The front section (2) comprising a front plate (3), a rear plate (4) and V-shaped corrugations (5) is also shown in Fig.2 in a schematic top view.

The front section (2) in the embodiment shown here illustrates that the rear plate (4) is located in parallel to the front plate (3). Furthermore, the V-shaped corrugations (5) are configured such that they connect the front plate (3) and the rear plate (4) of the front section (2). Accordingly, the V-shaped corrugations (5) are located such that they extend between the front plate (3) and the rear plate (4) of the front section (2)·

In one embodiment of the present invention, the front plate (3) and the rear plate (4) are arc-shaped, preferably arc-shaped in a direction perpendicular to an impact direction. Furthermore, the front plate (3) and the rear plate (4) of the front section (2) have essentially the same thickness "tl ". Additionally or alternatively, the front plate (3) and the rear plate (4) of the front section (2) have essentially the same height "h" (e.g. as shown in Fig. 2a). It is appreciated that the rear plate (4) is located in parallel to the front plate (3). Thus, the space "1" between the rear plate (4) and the front plate (3) is essentially even over the whole width and height of the front section (2) as shown in Fig. 2b. It is preferred that the space "1" between the rear plate (4) and the front plate (3) is from 5 to 50 mm, more preferably from 5 to 30 mm and most preferably from 10 to 20 mm.

The front section (2) of the lower bumper stiffener (1) further comprises V-shaped corrugations (5) extending between the front plate (3) and the rear plate (4). For example, the front section (2) of the lower bumper stiffener (1) can comprise V- shaped corrugations (5) in a direction perpendicular to an impact direction (e.g. Fig. 1 and Fig. 2). Preferably, the V-shaped corrugations (5) are configured between the front plate (3) and the rear plate (4) such that one side of the V-shaped corrugations (5) is attached to the front plate (3) and one side of the V-shaped corrugations (5) is attached to the rear plate (4) of the front section (2).

In one embodiment of the present invention, the V-shaped corrugations (5) of the front section (2) consist of a plurality of V-shaped units (5a) (e.g. Fig. 2a).

Preferably, the V-shaped corrugations (5) of the front section (2) consist of a plurality of continuous V-shaped units (5a) (e.g. Fig. 2a).

It is appreciated that the vertex angle "a" of each V-shaped unit (5a) is preferably essentially the same as illustrated in Fig. 2a. For example, each V-shaped unit (5a) has a vertex angle "a" of greater than zero and less than 120°. In one embodiment of the present invention, each V-shaped unit (5a) has a vertex angle "a" from 20° to 120°, preferably from 45° to 90° and most preferably from 60° to 90°.

Similarily as described for the height "h" of the front plate (3) and the rear plate (4) of the front section (2) above, the height "h" of the front plate (3) and of the rear plate (4) is essentially equal to the height "h" of the V-shaped corrugations (5) (as shown in Fig. 2a). Additionally or alternatively, the thickness "tl " of the V-shaped corrugations (5) is essentially the same as for the front plate (3) and the rear plate (4) of the front section (2).

In one embodiment of the present invention, the base plate (6) being attached to the bottom of the front section (2) has a thickness "tl " that is essentially the same as for the V-shaped corrugations (5) and/or the front plate (3) and the rear plate (4) of the front section (2).

Fig. 1 illustrates that the base plate (6) is attached to the bottom of the front section (2). Preferably, the base plate (6) is attached to the bottom of the front section (2) such that the front edge (7) of the base plate (6) joins the bottom of the front sections rear plate (4) essentially at right-angle.

Thus, it is preferred that the base plate (6) in the embodiment shown here comprises a front edge (7) being arc-shaped as also shown in Fig. 3 in a schematic top view. In order to ensure a sufficient stiffness, it is preferred that the arc shape of the front edge (7) of the base plate (6) is essentially identical to the arc of rear plate (4) of the front section (2). The front section (2) of the lower bumper stiff ener (1) is thus integrated on the base plate (6) with its rear plate (4). The bottom of the front section's rear plate (4) can be attached on the base plate (6) by any means suitable for joining them essentially at right-angle. Thus, the front section's rear plate (4) can be attached on the base plate (6) by attachment means such as for example screws, bolts, rivets, plug-in pins or the like, which may produce a firm connection between the rear plate (4) and the base plate (6). Preferably, the front section's rear plate (4) is moulded integrally on the base plate (6) of the lower bumper stiffener (1).

The rear edge (10) of the base plate (6) can be straight or curved. As shown in the schematic top view of Fig. 3, the rear edge (10) of the base plate (6) is preferably straight, more preferably perpendicular to an impact direction.

In order to ensure a sufficient stiffness, it is appreciated that the front section (2) as well as the longitudinal ribs (8) of the lower bumper stiffener (1) should be attached on an essentially even surface. Thus, it is preferred that the base plate (6) is essentially flat (see also Fig. 3a).

Fig 3a illustrates an embodiment of the base plate (6) comprising a rear flange (9). It is preferred that the thickness "tl "of the rear flange (9) is essentially equal to the thickness "tl " of the base plate (6). For example, the thickness "tl " is in the range from 1 to 10 mm, preferably from 1 to 6 mm, more preferably from 2 to 5 mm and most preferably from 3 to 4 mm. It is a further requirement of the present lower bumper stiffener (1) that longitudinal ribs (8) are attached to the upper surface of the base plate (6). The longitudinal ribs (8) can be attached on the base plate (6) by any means suitable for joining them together. Thus, the longitudinal ribs (8) can be attached on the base plate (6) by attachment means such as for example screws, bolts, rivets, plug-in pins or the like, which may produce a firm connection between the longitudinal ribs (8) and the base plate (6). Preferably, the longitudinal ribs (8) are moulded integrally on the base plate (6) of the lower bumper stiffener (1).

In one embodiment of the present invention, the longitudinal ribs (8) stand essentially at right-angles from the base plate (6) and are moulded integrally thereon. Preferably, the longitudinal ribs (8) and the base plate (6) are made from the same material.

The longitudinal ribs (8) in the embodiments shown herein are preferably attached to only one side of the base plate (6). More preferably, the longitudinal ribs (8) are attached to the same side of the base plate (6) as the front section (2) of the lower bumper stiffener (1) (see Fig. 1). That is to say, the longitudinal ribs (8) are preferably attached to the upper surface of the base plate (6). Accordingly, it is appreciated that the longitudinal ribs (8) and the front section (2) of the lower bumper stiffener (1) are preferably attached to the upper surface of the base plate (6).

The longitudinal ribs (8) extend essentially in an impact direction of the automotive vehicle. Preferably, the longitudinal ribs (8) are arranged parallel next to one another (see also Fig. 1 and Fig 4). The longitudinal ribs (8) extend essentially in horizontal direction approximately over the whole length and/or width, preferably length and width, of the base plate (6).

For example, the longitudinal ribs (8) extend from the rear plate (4) of the front section (2) to the rear edge (10) of the base plate (6) (see also Fig. 1). If the base plate comprises a rear flange (9), the longitudinal ribs (8) are encased by the rear plate (4) of the front section (2) and the rear flange (9) of the base plate (6), like a shell. In one embodiment of the present invention, one end of the longitudinal ribs (8) is thus attached vertically to the rear plate (4) of the front section (2) and the other end of the longitudinal ribs (8) is attached vertically to the rear flange (9) of the base plate (6) (see Fig. 1). The longitudinal ribs (8) can be attached vertically to the rear plate (4) of the front section (2) and the rear flange (9) of the base plate (6) by any means suitable for joining them together. Thus, the longitudinal ribs (8) can be attached vertically to the rear plate (4) of the front section (2) and the rear flange (9) of the base plate (6) by attachment means such as for example screws, bolts, rivets, plug-in pins or the like. Preferably, the longitudinal ribs (8) are moulded integrally to the rear plate (4) of the front section (2) and the rear flange (9) of the base plate (6).

Due to the arc-shape of the front sections' rear plate (4), it is appreciated that the length of the longitudinal ribs (8) preferably varies with location on the base plate (6) (see Fig. 1 and Fig. 4). Thus, it is preferred that the longitudinal rib (8) located at the central axle of the base plate (6) has the greatest length "LI " and the longitudinal rib (8) located at the lateral side, i.e. right and left lateral side, of the base plate (6) has the smallest length "L3". Accordingly, the longitudinal rib (8) located at the curvature inflexion of the front edge (7) of the base plate (6) has a length "L2". Preferably, length "L2" lies between length "LI " and "L3". It is preferred that the stiffness of the present lower bumper stiffener (1) can be improved if the longitudinal ribs (8) have a specific length relative to the space "1" between the rear plate (4) and the front plate (3) of the front section (2).

For example, the ratio of length "LI ", i.e. the length of the longitudinal rib (8) located at the central axle of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (Ll/1) is from 8 to 12, preferably from 8 to 11 and most preferably from 9 to 10.

Additionally or alternatively, the ratio of length "L3", i.e. the length of the longitudinal rib (8) located at the lateral side of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (L3/I) is from 1 to 3.5, preferably from 1.5 to 3.5 and most preferably from 2 to 3.5.

Additionally or alternatively, the ratio of length "L2", i.e. the length of the longitudinal rib (8) located between the longitudinal rib (8) at the central axle of the base plate (6) and the lateral side of the base plate (6), and located at the curvature inflexion of the front edge (7) of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (L2/1) is from 4 to 7.5, preferably from 5 to 7.5 and most preferably from 6 to 7.5.

In one embodiment of the present invention, the ratio of length "LI ", i.e. the length of the longitudinal rib (8) located at the central axle of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (Ll/1) is from 8 to 12, preferably from 8 to 1 1 and most preferably from 9 to 10, and the ratio of length "L3", i.e. the length of the longitudinal rib (8) located at the lateral side of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (L3/1) is from 1 to 3.5, preferably from 1.5 to 3.5 and most preferably from 2 to 3.5, and the ratio of length "L2", i.e. the length of the longitudinal rib (8) located between the longitudinal rib (8) at the central axle of the base plate (6) and the lateral side of the base plate (6), to the space "1", i.e. the space between the rear plate (4) and the front plate (3) of the front section (2), (L2/1) is from 4 to 7.5, preferably from 5 to 7.5 and most preferably from 6 to 7.5.

As illustrated by Fig. 1 and Fig. 4, the longitudinal ribs (8) are preferably arranged parallel next to one another. It is appreciated that the longitudinal ribs (8) are preferably attached essentially even on the upper surface of the base plate (6). Thus, it is preferred that the distance "d" between the longitudinal ribs (8) is essentially even. For example, the distance "d" between two adjacent longitudinal ribs (8) is from 10 to 60 mm, preferably from 20 to 50 mm, and most preferably from 20 to 30 mm. Additionally or alternatively, the height "h" of the longitudinal ribs (8) is essentially equal to the height "h" of the V-shaped corrugations (5) and/or the height "h" of the front plate (3) and of the rear plate (4) of the front section (2). Preferably, the height "h" of the longitudinal ribs (8) is essentially equal to the height "h" of the V-shaped corrugations (5) and the height "h" of the front plate (3) and of the rear plate (4) of the front section (2).

It is preferred that all longitudinal ribs (8) have essentially the same thickness "t2". For example, the thickness "t2" is in the range from 0.5 to 10 mm, preferably from 1 to 6 mm, more preferably from 2 to 5 mm and most preferably from 3 to 4 mm.

In order to provide a sufficient stiffness of the lower bumper stiffener (1), a specific ratio of height "h" of longitudinal ribs (8) to thickness "tl " of the base plate (6) should be met. It is thus preferred that the ratio of height "h" to thickness "tl " (h/tl) in the range from 2 to 5, preferably in the range from 3 to 5 and most preferably from 4 to 5. It is preferred that the thickness "t2" of the longitudinal ribs (8) is the same or below the thickness "tl" of the base plate (6). For example, the ratio of thickness "t2" of the longitudinal ribs (8) to the thickness "tl " of the base plate (6) (t2/tl) is preferably from 0.4 to 1.0, preferably from 0.5 to 0.8 and most preferably from 0.5 to 0.75.

The invention discussed above provides a lower bumper stiffener (1) for an automotive vehicle for the protection of pedestrians during collision of a pedestrians' lower leg against the lower region of a front bumper. The lower bumper stiffener (1 ) of the present invention is preferably arranged behind the front bumper fascia, close to the bottom of the front bumper fascia, with a small gap to the front bumper fascia, and extends across substantially the full width of the bumper fascia. The lower bumper stiffener (1) may be attached to engine compartments or to support of the cooling pack. Preferably, it is simultaneously attached to the front bumper fascia via point connection, such as by bolt or snap- fit.

In view of the excellent results obtained for the present lower bumper stiffener (1), the present invention is further directed to an automotive vehicle comprising the lower bumper stiffener (1).

While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a number of variations exist. It should also be appreciated that the exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient concept for implementing an exemplary embodiment of the invention. It is understood that various changes may be made in the function and arrangement of the elements described in the exemplary embodiments without departing from the scope of the invention as set forth in the attached claims and their legal equivalents. The following examples and tests will illustrate the present invention, but are not meant to restrict the invention to the exemplified embodiments. The examples below show the dimensions of an exemplified lower bumper stiffener (1) according to the present invention and its stiffness values.

EXAMPLES Example 1

Test 1

Table 1 outlines the relevant dimensions of the single components of a lower bumper stiffener (1) prepared in this Example, i.e. the front section (2), the base plate (6) and the longitudinal ribs (8), and stiffness thereof tested.

The lower bumper stiffener is used to be assembled into a car (Toyato Yaris 2010). The arc of front plate (3) and rear plate (4) of the front section (2) corresponds to the arc of front bumper fascia of the car, i.e. Toyato Yaris 2010.

The lower bumper stiffener (1) is prepared by injection-moulding, and the whole structure is made and formed integrally in one injection-moulding process.

Material for preparing the lower bumper stiffener is a glass fiber-reinforced PP. It comprises 60% homo PP, 30% SGF, and balanced regualr additives, and has a MFR of 4.5/10min. The glass fiber is SGF (short glass fiber), having an aspect ratio of 50.

The lower bumper stiffener (1) was manufactured by the injection-molding machine "Engle 1500T" of Engle Austria GmbH. The injection-moulding machine has a barrel for heating and plastizing the material. The temperatures in the zones of heating and plastizing of the barrel were in sequence 210°C, 220°C, 230°C, 240°C. The temperature of injecting the melt and melt temperature at gate of the mold were 240°C. The injection pressure was set to 30MPa and the injection speed was

200cm ³ /second. Injection time was 4 sec. After injection, the pressure of mold was maintained at 20MPa. for lOsec, and then cooled down. The mold for preparing the lower bumper stiffener (1) was made by Hangyan Xingtai Plastic Mold Co. Ltd, Huangyan, Zhejiang, China. The mold includs two parts: core side and cavity side. The core side has a relief pattern corresponding to the target structure, and the cavity side has a concave pattern with an enantiomorphous shape and size to the pattern on the core side.

The stiffness was determined by computer simulation by using the software

ABAQUS (version 6.12-2, 2013)/ Standard code, which is used widely in

engineering simulation.

In the test, the rear flange (9) of the base plate (6) is fixed and 2400N load is applied on two areas of 320mm ² of the front plate (3) of the front section (2), i.e. the center of the front plate (3) and the curvature inflexion of the arc of the front plate (3) of the front section (2). Deformation at the two test points in load application direction was measured at room temperature and represented as Ul (center of the front plate (3) of the front section (2)) and U2 (curvature inflexion point of the front plate (3) of the front section (2)) respectively. Stiffness is defined as the applied load divided by Ul or U2. Table 1 :

tl a 1 Ll/1 L2/1 L3/1 t2/tl d h/tl Ul U2 [mm] [°1 [mm] [mm] [mm] [mm]

(stiffness) (stiffness)

3.2 90 15 9.3 6.9 2.5 0.5 20 5 2.1 1 2.23

(1 137N/mm) (1076N/mm) Note: stiffness tested is 1137 and 1076 N/mm, corresponding respectively to Ul and U2.

Test 2

ABAQUS/ EXPLICIT module code and FLEX PLI GTR (version 2.0) legform dummy were used to test legform pedestrian protection by computer simulation according to the requirements of the Assessment Protocol of Euro NCAP (version 2014). The lower bumper stiffener was assembled into a car (Toyato Yaris 2010) by connecting it to bumper fascia and support of cooling pack via five points (center, two lateral sides, two points between center and lateral side) respectively. A FLEX PLI GTR legform dummy hits the center of the bumper fascia of the car at an initial velocity of 40km/hr. Three parameters of the legform dummy were determined at room temperature: Tibia Bending moment, MCL (Medial Collateral Ligament) elongation and ACL (Anterior Collateral Ligament) /PCL (Posterior Collateral Ligament) elongation. Tibia Bending moment represents tibia injury, which is the worst performing of tibia moments. MCL elongation and ACL/PCL elongation represent knee injury.

The test values in comparison to the allowable criteria according to Euro NCAP criteria are outlined in Table 2.

Table 2:

Tibia bending Euro MCL Euro ACL PCL Euro moment NCAP elongation NCAP elongation NCAP criteria criteria criteria

201.1Nm < 282Nm 9.1mm < 19mm 6.7mm < lOmm From Table 2 it can be gathered that the lower bumper stiffener (1) of this Example of the present invention shows an excellent performance in the tests and thus provides an excellent lower leg pedestrian protection. Furthermore, the lower bumper stiffener (1) is reduced in weight and can be produced at lower cost than lower bumper stiffener made from glass-fiber reinforced polyamide or metal.

Example 2

Table 3 outlines the relevant dimensions of the single components of another lower bumper stiffener (1 ), i.e. the front section (2), the base plate (6) and the longitudinal ribs (8), and stiffness thereof. The lower bumper stiffener (1) of Example 2 was manufactured as described for Example 1. Further, the lower bumper stiffener (1) had the same mass as the lower bumper stiffener (1) of Example 1. The stiffness was tested and determined as outlined above for Test 1.

Table 3:

Table 4 outlines the Tibia Bending moment, MCL (Medial Collateral Ligament) elongation and ACL (Anterior Collateral Ligament) /PCL (Posterior Collateral Ligament) elongation as determined for the lower bumper stiffener. The values were tested and determined as outlined above for Test 2.

Table 4:

Tibia bending Euro 1 MCL Euro ACL PCL Euro moment NCAP elongation NCAP elongation NCAP criteria criteria criteria

225.8Nm < 282Nm 1 1.5mm < 19mm 7.1mm < 10mm

From Table 4 it can be gathered that the lower bumper stiffener (1 ) of Example 2 of the present invention shows an excellent performance in the tests and thus provides an excellent lower leg pedestrian protection. Furthermore, the lower bumper stiffener (1) is reduced in weight and can be produced at lower cost than lower bumper stiffener made from glass-fiber reinforced polyamide or metal.

Example 3

Table 5 outlines the relevant dimensions of the single components of another lower bumper stiffener (1), i.e. the front section (2), the base plate (6) and the longitudinal ribs (8), and stiffness thereof. The lower bumper stiffener (1) of Example 3 was manufactured as described for Example 1. Further, the lower bumper stiffener (1) had the same mass as the lower bumper stiffener (1) of Example 1.

The stiffness was tested and determined as outlined above for Test 1.

Table 5:

Table 6 outlines the Tibia Bending moment, MCL (Medial Collateral Ligament) elongation and ACL (Anterior Collateral Ligament) /PCL (Posterior Collateral Ligament) elongation as determined for the lower bumper stiffener. The values were tested and determined as outlined above for Test 2.

Table 6:

From Table 6, it can be also gathered that the lower bumper stiffener (1) of Example 3 of the present invention shows an excellent performance in the tests and thus provides an excellent lower leg pedestrian protection. Furthermore, the lower bumper stiffener (1) is reduced in weight and can be produced at lower cost than lower bumper stiffener made from glass-fiber reinforced polyamide or metal. Example 4

Table 7 outlines the relevant dimensions of the single components of another lower bumper stiffener (1), i.e. the front section (2), the base plate (6) and the longitudinal ribs (8), and stiffness thereof. The lower bumper stiffener (1) of Example 4 was manufactured as described for Example 1. Further, the lower bumper stiffener (1) had the same mass as the lower bumper stiffener (1) of Example 1.

The stiffness was tested and determined as outlined above for Test 1.

Table 7:

tl a 1 Ll/1 L2/1 L3/1 t2/tl d h/tl Ul U2 [mm [°] [mm] [mm] [mm] [mm] 1 (stiffness) (stiffness)

3.6 60 17 8.2 5.9 2.2 1.0 40 5 2.8 2.9

(857N/mm) (828N/mm) Table 8 outlines the Tibia Bending moment, MCL (Medial Collateral Ligament) elongation and ACL (Anterior Collateral Ligament) PCL (Posterior Collateral Ligament) elongation as determined for the lower bumper stiffener. The values were tested and determined as outlined above for Test 2.

Table 8:

From Table 8 it can be also gathered that the lower bumper stiffener (1 ) of Example 4 of the present invention shows an excellent performance in the tests and thus provides an excellent lower leg pedestrian protection. Furthermore, the lower bumper stiffener (1 ) is reduced in weight and can be produced at lower cost than lower bumper stiffener made from glass-fiber reinforced polyamide or metal.