System for detecting a pedestrian collision with a vehicle, use of the system and vehicle with such a system

Abstract

System (21) for detecting an impact by a pedestrian (5) on a vehicle (1), characterized by the following features: - the system includes a plastic carrier (4) adapted to a crash management system (3) of the vehicle, - the plastic carrier consists of a fixed part (4.1), several elements (4.2) which are slidable towards the fixed part (4.1) and each have at least one chamber (10) and means for attaching it to the crash management system (3), - the solid part (4.1) contains damping foam (6) with an embedded rubber tube (7) for absorbing the impact, - each element is traversed by a first channel (8) and the solid part by a second channel (9.1) and - the first channels (8) open into the second channel (9.1) and are fluidically connected to the chambers (10) in such a way that they allow fluid (15) displaced from the chambers upon impact to escape from the system (21) in a limited volume flow.

Description

[0001] The present invention relates to a system for detecting a collision between a pedestrian and a vehicle. The present invention further relates to the use of this system and to a motor vehicle equipped with such a system. State of the art

[0002] In the field of pedestrian protection in motor vehicles, various technologies have become established to minimize the risk of injury to pedestrians in a collision with a vehicle. These technologies are regulated by law in the European Union as well as in other regions, including the United States, and require continuous development to meet increasing safety requirements.

[0003] To protect pedestrians from serious head injuries that can occur in collisions where their head comes into contact with the hood or windshield, vehicles are often equipped with deformable hoods. This design effectively absorbs impact energy, thus reducing the forces acting on the pedestrian.

[0004] Furthermore, modern vehicles employ active safety systems. These systems include airbags that deploy over the hood, as well as adjustable hoods that lift upon impact, thereby creating a larger deformation zone. These active systems complement passive safety measures through structural improvements and further contribute to reducing the risk of injury in accidents involving pedestrians.

[0005] Another aspect of pedestrian protection is the early detection of a pedestrian collision. Contact-based sensor systems are primarily used for this purpose. These systems typically consist of a rubber hose mounted along the front of the vehicle and equipped with pressure sensors at its ends. Upon impact, the rubber hose deforms, causing an increase in internal pressure. This pressure increase is detected and evaluated by the sensors, triggering the deployment of safety systems such as airbags.

[0006] In the United States, vehicles must also meet the requirements of the "US Part 581" standard, known as the pendulum test. In this test, the front of the vehicle is subjected to the force of a pendulum with the same mass as the vehicle itself. After the pendulum impact, there must be no obvious damage to the vehicle, and all driver assistance systems must remain functional. For this test, a stiffer absorption foam is often placed in front of the actual crash management system to protect the vehicle structure and reliably meet the standard's requirements.

[0007] DE 10 2014 214 595 A1, DE 10 2017 116 814 A1 and DE 60 2005 000 945 T2 each disclose the subject matter of the preamble of claim 1 and embody the prior art from which the invention is based. Disclosure of the invention

[0008] A problem in the current design of vehicle safety systems, particularly in the area of ​​pedestrian protection, arises from the need to meet both the stringent safety requirements for pedestrian protection in an accident and the legal requirements for the vehicle structure in minor collisions (so-called parking bumps). This dual requirement leads to a conflict of objectives in vehicle design, especially when integrating pedestrian impact detection systems.

[0009] Using a rigid foam poses a risk that the rubber tube used to detect pedestrian impacts will not be sufficiently compressed in the event of an actual pedestrian collision, as the foam prevents the necessary deformation of the tube to activate the sensor. This failure to detect the pedestrian impact and subsequently activate the appropriate protective measures represents a significant safety risk.

[0010] The problem described is solved by a system for detecting an impact by a pedestrian, a method for using this system, and a motor vehicle with such a system according to the independent claims.

[0011] This approach resolves the described conflict of objectives by enabling improved sensitivity and adaptability to different impact situations. The system is able to reliably detect pedestrian impacts without compromising the protection of the vehicle structure according to the stringent requirements of the "pendulum test".

[0012] The new system is characterized by increased flexibility in pressure detection. It is able to react to the specific characteristics of various impact situations, be it the impact of a human leg or a minor parking bump. This adaptability helps to optimize the activation of active protection systems according to the actual hazard situation and, in particular, to minimize false activations.

[0013] Another advantage of the system is that it requires no additional installation space. This is particularly important for vehicle design, as the available space in the front of the vehicle is limited.

[0014] In this way, the system enables manufacturers to increase pedestrian safety without having to compromise on vehicle design.

[0015] Further advantageous embodiments of the invention are specified in the dependent patent claims. Brief description of the drawings Fig. Figure 1 shows a hood airbag. Fig. Figure 2 shows a hood tilted upwards. Fig. Figure 3 shows the detection of a pedestrian and the activation of an active hood. Fig. Figure 4 shows the activation of the active hood and the creation of a deformation space for the pedestrian's head. Fig. Figure 5 shows the deformation of the hood when absorbing the kinetic energy. Fig. Figure 6 shows a vehicle with absorption foam in front of the crash management system. Fig. Figure 7 shows the vehicle in a more detailed view of the front end. Fig. Figure 8 shows the absorption foam and the hose embedded within it in the initial state. Fig. Figure 9 shows the vehicle colliding with a pedestrian. Fig. Figure 10 shows the compressed absorption foam and hose after the impact. Fig. Figure 11 shows the perspective view of a system according to the invention. Fig. Figure 12 shows a cross-section of the system during the impact of a pedestrian's leg. Fig. Figure 13 shows the corresponding cross-section of the system after the impact of the leg. Fig. Figure 14 shows a longitudinal section of the system during the impact of the leg and another vehicle. Fig. Figure 15 shows the fixed part and a movable element of the plastic carrier in a first isometric representation. Fig. Figure 16 shows the solid part in a second isometric view. Embodiments of the invention

[0016] The Fig. 1 and Fig. Figure 2 shows two different active systems for pedestrian protection: a hood airbag ( Fig. 1) and an upward-sloping hood ( Fig. 2) These systems are designed to cushion the impact of a pedestrian and minimize the risk of injury. Fig. 3 and Fig. Figure 4, taken together, illustrates the operation of such an active hood, which lifts slightly after detecting the impact, thus mitigating the impact on the pedestrian. Fig. Figure 5 shows the deformation of the hood resulting from the impact, which absorbs the kinetic energy of the pedestrian.

[0017] The Fig. Figures 6 to 10 show a conventional contact-based system for detecting such a pedestrian impact, consisting of an absorption foam (2) of thickness x (2.1) and a hose (9) embedded therein. This system is installed in the vehicle (1) upstream of its crash management system (3). Upon impact, the foam (2.2) is compressed, causing the squeezed hose (9) to send a signal to activate the active protection system (see Figure 6 to 10). Fig. 3 to 5).

[0018] The Fig. Figures 11 to 16 show an embodiment of the invention, which provides an improved system for detecting pedestrian impacts. The system comprises a plastic carrier (4) consisting of a fixed part (4.1) and several movable elements (4.2). The width (20) of the movable elements (4.2) is selected such that they generate the required pressure increase upon impact by a pedestrian, while the system (21) withstands a wider impact.

[0019] The solid part (4.1) of the plastic carrier (4) is designed for this purpose according to Fig. 12 is attached to the vehicle's crash management system (3) by means of a collar (4.3) and, in a manner comparable to a conventional system, carries a damping foam (6) with an embedded rubber hose (7) as well as a plurality of guide pins (11) that project in parallel rows along the carrier (4) in the direction of travel. Each of the movable elements (4.2) is mounted onto two of these pins (11) in such a way that a cavity remains between the element (4.2) and the pin (11) in the extension of each pin. The guide pin (11) can thus act as a piston that can displace the air or other fluid located in this chamber (10) when the movable structure (4.2) is moved.

[0020] For example, according to Fig. 13. In the event of a pedestrian impact with their leg (100), the vehicle's attachments are pushed onto some of the sliding elements (4.2). These elements are moved until their distance to the respective pins (11) is exhausted. During this process, the fluid in the chambers is displaced and directed through a channel (8) running through each element into a second channel (9.1) in the fixed part (4.1) of the plastic carrier. Simultaneously, the damping foam (6) is compressed (16) and the rubber hose (7) is pressed in (17), triggering the signal to ignite the protection system.

[0021] Fig. Figure 14 examines this aspect of the system's venting in detail, noting that a viscous fluid (15) such as oil can be used instead of air. The ratio of the piston areas and the cross-section of the channels (9.1) and outlet opening (105) are chosen such that, on the one hand, in the event of an impact limited to the circumference (101) of the leg (100) and thus only compressing individual elements (4.2), the correspondingly small amount ΔV of displaced fluid escapes quickly and without resistance through the outlet opening (105). On the other hand, the cross-section is sufficiently narrow that the larger amount ΔV displaced in a large-area impact from the circumference (301) of another vehicle (300) – for example, in a minor parking collision – does not escape so quickly that the damping foam (6- Fig. 15 and Fig. 16) would be compressed. Reference symbol description 1 vehicle 2 absorption foam 2.1 Thickness x (of the absorption foam) 2.2 Compressed absorption foam 3 Crash Management System (CMS) 4 plastic carriers (structure) 4.1 fixed part (of the plastic carrier) 4.2 (Movable) element (of the plastic carrier) 4.3 Collar (of the plastic carrier for its attachment) 5 pedestrians 6 damping foam (in its initial state) 7 rubber hose 8 first channel (in element) 9 hose (behind absorption foam) 9.1 second channel (in fixed part) 10 chambers 11 guide pins 15 (fluid escaping from the chambers through the channels) 16 compressed damping foam 17 compressed rubber hose 20 Width (of the elements) 21 System 100 Leg of the pedestrian 101 circumference corresponding to the leg 105 Outlet opening (of the second channel) 300 more vehicles 301 Scope corresponding to the other vehicle

Claims

[1] System (21) for detecting an impact by a pedestrian (5) on a vehicle (1), characterized by the following characteristics: - the system includes a plastic carrier (4) adapted to a crash management system (3) of the vehicle, - the plastic carrier consists of a fixed part (4.1), several elements (4.2) which are slidable towards the fixed part (4.1) and each have at least one chamber (10) and means for attaching it to the crash management system (3), - the solid part (4.1) contains damping foam (6) with an embedded rubber tube (7) for absorbing the impact, - each element is traversed by a first channel (8) and the solid part by a second channel (9.1) and - the first channels (8) open into the second channel (9.1) and are fluidically connected to the chambers (10) in such a way that they allow fluid (15) displaced from the chambers upon impact to escape from the system (21) in a limited volume flow. [2] System according to claim 1, characterized by the following characteristics: - the fixed part (4.1) is provided with guide pins (11) on both sides of the damping foam (6) for guiding the elements (4.2) during the impact and - the chambers (10) are each located in extension of one of the guide pins (11), so that the latter displace the fluid (15) upon impact. [3] System according to claim 2, characterized by the following characteristics: - the guide pins (11) are arranged in two parallel rows along the plastic carrier (4) and - the damping foam (6) extends between the rows over the solid part (4.1). [4] System according to claim 3, characterized bythe following characteristics: - the guide pins (11) are arranged in pairs consisting of one pin from the upper and one from the lower row and - each of the pairs projects parallel into one of the elements (4.2). [5] System according to any one of claims 1 to 4, characterized by the following characteristic: - the solid part (4.1) and the elements (4.2) are shaped in such a complementary way that, when the guide pins (11) have completely displaced the fluid (15), the latter compress the damping foam (6) and rubber hose (7). [6] System according to claim 5, characterized by the following characteristic: - the elements (4.2) are each of such a small width (20) that compression occurs when the impact is limited to a circumference (101) corresponding to a human leg. [7] System according to claim 5 or 6, characterized by the following characteristic: - the second channel (9.1) has an outlet opening (105) of defined cross-section and - the cross-section is so narrow that compression does not occur if the impact assumes a circumference (301) corresponding to another vehicle (300). [8] Use of a system according to any one of claims 1 to 7, characterized by at least one of the following characteristics: - the chambers (10) are filled with air or - the chambers (10) are filled with oil. [9] Motor vehicle (1), characterized by the following characteristics: - the motor vehicle includes a crash management system (3) and a system connected thereto according to one of claims 1 to 7 and - the motor vehicle has a hood designed to cushion the impact. [10] Motor vehicle according to claim 9, characterized by at least one of the following characteristics: - the vehicle contains an airbag and is designed to deploy it over the hood upon impact, or - the vehicle is designed to raise the hood upon impact with the pedestrian.

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