Patent Abstract:
A pedestrian protection system for a motor vehicle includes an impact recognition sensor for recognizing an impact of the motor vehicle with a pedestrian. The impact recognition sensor is located in a front fender of the motor vehicle, next to an outer skin that lines the fender, or in a front part of the motor vehicle, next to an outer skin that lines the front part of the motor vehicle.

Full Description:
FIELD OF THE INVENTION 
     The present invention relates to a pedestrian protection system for a motor vehicle, e.g., having an impact detection sensor for detecting an impact of a pedestrian on the motor vehicle as well as a bumper for a motor vehicle, the bumper including a support made of a stiff material, an outer skin for covering the bumper and an elastic layer situated between the support and the outer skin. 
     BACKGROUND INFORMATION 
     Pedestrian protection systems are described, e.g., in European Published Patent Application No. 0 914 992 and German Published Patent Application No. 100 16 142 as well as from the related art discussed in German Published Patent Application No. 100 16 142. German Published Patent Application No. 100 16 142 describes, e.g., a person protection system having a trigger switch, the trigger switch having a first pair of contacts and at least one second pair of contacts which is operable by pressure and by which an electric circuit may be closed and thereby a contact signal produced, the first and the second pair of contacts being situated at a spatial distance from each other. 
     SUMMARY 
     Example embodiments of the present invention may provide an improved pedestrian protection system. For this purpose it is desirable to find a particularly good compromise between a low false triggering of the pedestrian protection system, a reliable triggering of the pedestrian protection system in the event of an impact of a pedestrian on the motor vehicle and a quick triggering of the pedestrian protection system in the event of an impact of a pedestrian on the motor vehicle. 
     A pedestrian protection system for a motor vehicle may include an impact detection sensor for detecting an impact of a pedestrian on the motor vehicle, the impact detection sensor being situated in a front bumper of the motor vehicle near an outer skin for covering the bumper and/or in a front part of the motor vehicle near an outer skin for covering the front part of the motor vehicle. In this connection, when a collision with a pedestrian is detected, the impact detection sensor may trigger a protective mechanism such as, e.g., a raising of an engine hood as described, e.g., in German Published Patent Application No. 100 16 142. 
     The impact detection sensor may have a side facing the outer skin and a side facing away from the outer skin, the side of the impact detection sensor facing away from the outer skin being, e.g., less than 25 mm away from the outer skin. The side of the impact detection sensor facing the outer skin may substantially or nearly touch the outer skin. 
     A bumper for a motor vehicle includes a support made of a stiff material, e.g., steel, an outer skin for covering the bumper and an elastic layer (such as, e.g., a foam member) situated between the support and the outer skin, and the bumper having an impact detection sensor, situated between the support and the outer skin near the outer skin, for detecting an impact of a pedestrian on the motor vehicle. In this connection, when a collision with a pedestrian is detected, the impact detection sensor may trigger a protective mechanism such as, e.g., a raising of an engine hood as described, e.g., in German Published Patent Application No. 100 16 142. 
     The impact detection sensor may have a side facing the outer skin and a side facing away from the outer skin, the side of the impact detection sensor facing away from the outer skin being, e.g., less than 25 mm away from the outer skin. The side of the impact detection sensor facing away from the outer skin essentially or nearly touches the elastic layer. 
     In another advantageous refinement of the present invention, the side of the impact detection sensor facing the outer skin may substantially or nearly touch the outer skin. 
     The elastic layer may include foamed material or may be made up substantially of foamed material. 
     A motor vehicle—e.g., including the above-mentioned characteristics—may have a first impact detection sensor for detecting an impact of a pedestrian on the motor vehicle and at least one second impact detection sensor for detecting an impact of a pedestrian on the motor vehicle, the first impact detection sensor being situated in a front bumper of the motor vehicle, e.g., at a distance of less than 25 mm from an outer skin for covering the bumper and/or in a front part of the motor vehicle at a distance of less than 25 mm, e.g., less than 10 mm, from an outer skin for covering the front part of the motor vehicle, and the second impact detection sensor, e.g., being situated on a pedestrian protection support of the motor vehicle. 
     Impact detection sensors may be, e.g., contact sensors (such as fiber-optic sensors for example), force sensors or sensors arranged according to the sensor described in German Published Patent Application No. 100 16 142. 
     An arrangement near an outer skin may include an arrangement at a distance of, e.g., less than 25 mm, e.g., less than 10 mm, from the outer skin. 
     A motor vehicle may include a land vehicle that may be used individually in road traffic. Motor vehicles are not, however, restricted to land vehicles having an internal combustion engine. 
     Further aspects and details of exemplary embodiments of the present invention are described below with reference to the appended Figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an exemplary embodiment of a pedestrian protection system of a motor vehicle. 
         FIG. 2  is a cross-sectional view through a segment of the front part of the motor vehicle illustrated in  FIG. 1 . 
         FIG. 3  is a front view of a motor vehicle. 
         FIG. 4  is another front view of a motor vehicle. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a pedestrian protection system  16 , modified with respect to the person protection system described, e.g., in German Published Patent Application No. 100 16 142, for a motor vehicle  10  for protecting pedestrians  14 . 
     The pedestrian protection system  16  has a raisable engine hood  22 , which is raisable using an engine hood airbag device  24 . In order to prevent a firing of engine hood airbag device  24  from raising engine hood  22  more than a predefined distance, an engine hood catching device  25  in the form of a cable line, a chain or a stop is provided. Engine hood includes, e.g., a covering of a space lying in front of a passenger compartment of a motor vehicle. 
     Pedestrian protection system  16  includes a control system  31  by which the engine hood airbag device  24  is triggered if a collision with a pedestrian  14  is detected by an impact detection sensor  32  illustrated in  FIG. 1  and situated in a front bumper  30 . For this purpose, control system  31  and impact detection sensor  32  are suitably connected to each other in terms of data technology. 
     If the velocity of the motor vehicle, which is determinable with the aid of impact detection sensor  32  using an impact detection sensor, such as that described, e.g., in German Published Patent Application No. 100 16 142, lies within a predefined velocity window of, e.g., 20 km/h to 50 km/h, then the pyrotechnic charge of engine hood airbag device  24  is triggered. If the velocity lies above the velocity window, then control system  31  locks engine hood  22  using a locking device  48 , which, e.g., secures catching device  25 . An activation of the pyrotechnic charge of engine hood airbag device  24  does not occur. 
       FIG. 2  is a cross-sectional view through a segment of the front part of motor vehicle  10  including bumper  30  in a detailed view. Bumper  30  includes a steel support  35 , on whose side  39  facing the front side of motor vehicle  10  a solid or honeycomb-structured foam member  34  is situated. Foam member  34  is covered by an outer skin  33 . 
     Bumper  30  has an impact detection sensor  32  situated between steel support  35  and outer skin  33 —e.g., between foam member  34  and outer skin  33 —at a distance of, e.g., less than 25 mm from the outer skin. The present exemplary embodiment provides for impact detection sensor  32  or for side  45  of impact detection sensor  32  facing outer skin  33  substantially or nearly to touch outer skin  33 . Side  46  of impact detection sensor  32  facing away from outer skin  33  is, e.g., less than 25 mm away from outer skin  33 . In addition, side  46  of impact detection sensor  32  facing away from outer skin  33  substantially or nearly touches foam member  34 . 
     There may be an optional provision for motor vehicle  10  to have at least one additional impact detection sensor  36  for detecting an impact of a pedestrian  14  in or on a pedestrian protection support  37  of motor vehicle  10 . In this instance, there may be a provision for control system  31  to evaluate also a time difference between a signal of impact detection sensor  32  indicating an impact and a signal of impact detection sensor  36  indicating an impact in order to differentiate between an impact of a pedestrian  14  from an impact of an object, for example. 
     Impact detection sensors  32  and  36  may be, e.g., contact sensors (such as fiber-optic sensors, for example), force sensors or sensors arranged according to the sensor described, e.g., in German Published Patent Application No. 100 16 142. Sensors arranged in accordance with the sensor described in German Published Patent Application No. 100 16 142, that is, sensors having at least one, e.g., two pairs of contacts, which by contact close an electric circuit in the event of an impact, may be provided for impact detection sensor  32 , that is, an impact detection sensor situated in a bumper. 
       FIG. 3  and  FIG. 4  each show a front view of a motor vehicle  50  or  60 . In this instance, reference numerals  51 ,  52 ,  61 ,  62 ,  63  and  64  indicate regions (e.g., not visible from outside), in which impact detection sensors may be situated in a segmented or in a continuous manner. Thus, e.g., motor vehicle  50  may correspond to motor vehicle  10 , it being possible for impact detection sensor  32  to be situated in a segmented or in a continuous manner in region  51  and impact detection sensor  36  to be situated in a segmented or in a continuous manner in region  52 . Motor vehicle  60  may also correspond to motor vehicle  10 , for example, it being possible for impact detection sensor  32  to be situated in a segmented or in a continuous manner in regions  61 ,  62  and  63 . There may also be a provision, alternatively or additionally to impact detection sensor  36 , for an impact detection sensor to be situated in region  64 . 
     LIST OF REFERENCE NUMERALS 
     
         
           10 ,  50 ,  60  motor vehicle 
           14  pedestrian 
           16  pedestrian protection system 
           22  engine hood 
           24  engine hood airbag device 
           25  engine hood catching device 
           30  bumper 
           31  control system 
           32 ,  36  impact detection sensor 
           33  outer skin 
           34  foam member 
           35  steel support 
           37  pedestrian protection support 
           39  side of a steel support facing the front side of a motor vehicle 
           45  side of an impact detection sensor facing the outer skin 
           46  side of an impact detection sensor facing away from the outer skin 
           48  locking device 
           51 ,  52 ,  61 ,  62 , 
           63 ,  64  region

Technology Classification (CPC): 1