Abstract:
An energy absorption system, comprises a vehicle bumper. An energy absorption member is attached to the bumper, the energy absorption member comprising a first piece and a second piece. A linear actuator connects the energy absorption member to the bumper. The actuator may be actuated based on the speed information from the onboard vehicle communication network.

Description:
BACKGROUND 
     Requirements for protecting a vehicle front end may conflict for different crash scenarios. For example, low-speed damageability (LSD) and pedestrian protection requirements may differ. LSD requirements generally dictate that no or minimal damage occurs to various vehicle front end components, e.g., side rails, radiator supports, doors, fenders, hood, hinges, headlamps, etc., at low speeds, e.g., speeds below 15 kilometers per hour (KPH). Accordingly, LSD scenarios generally require that approximately 80 percent of impact energy from a collision be absorbed by a vehicle bumper at speeds of 15 KPH or less. In contrast, pedestrian protection requirements are generally designed to limit pedestrian leg injuries to certain knee shear and bending moment targets at relatively higher speeds, e.g., around 40 kilometers per hour. Accordingly, relative to one another, LSD scenarios generally require a stiff bumper system, whereas pedestrian protection scenarios generally require a softer bumper mechanism. Unfortunately, current vehicle bumper systems are not adaptable to meet these different requirements. There is a need for a vehicle bumper system that can adapt to the respective requirements of an LSD scenario and a pedestrian protection scenario. 
    
    
     
       DRAWINGS 
         FIG. 1  is a perspective view of an example of an adaptive energy absorber system and a vehicle front fascia. 
         FIG. 2  is a perspective view of an example of an adaptive energy absorber system in a first state. 
         FIG. 3  is a perspective view of the adaptive energy absorber system of  FIG. 1  in a second state. 
         FIG. 4  is a perspective view of an end portion of the adaptive energy absorber system of  FIG. 1  in the first state. 
         FIG. 5  is a perspective view of an end portion of the adaptive energy absorber system of  FIG. 1  in the second state. 
         FIG. 6  is a perspective view of a center portion of the adaptive energy absorber system of  FIG. 1  including a detail view of a linear actuator. 
         FIG. 7  is a perspective detail view of linear actuator including the actuator head bracket, and a vehicle bumper. 
         FIG. 8  is a block diagram of a vehicle bumper control system. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein and illustrated in the various figures is an adaptive energy absorber system  10  for a vehicle. As seen in  FIG. 1 , a vehicle front fascia  12 , which is shown for completeness and context, but which is not necessary to the energy absorber system  10 , may cover a bumper  14  and an energy absorber  16  affixed to the bumper  14 . The fascia  12  could be affixed to the energy absorber  16  with a low density foam or the like (not shown) to allow the fascia  12  to maintain a desired shape.  FIG. 2  shows the system  10 , including an energy absorber  16 , in a first state, e.g., in a position to accommodate low-speed damageability requirements.  FIG. 3  shows the system  10 , including an energy absorber  16 , in a second state, e.g., in a position to accommodate pedestrian protection requirements, i.e., at higher speeds. In the first state, the system  10  is deployed to absorb a greater amount of impact energy than when deployed in the second state. 
     With reference to  FIGS. 1-3 , the bumper  14  may be a conventional vehicle bumper, e.g., formed of steel or the like. The energy absorber  16  may be any one of a variety of materials, depending on energy absorption requirements, such as an elastomeric plastic, sheet metal, etc. Moreover, the energy absorber  16  generally includes a first piece  17  and a second piece  18  made of such materials. The pieces  17 ,  18  may be secured to one another via a variety of mechanisms, such as an adhesive and/or friction. The bumper  14  may further have affixed thereto side members, e.g., crash cans,  15 . The bumper  14 , e.g., via the crash cans  15 , may be attached to a vehicle front end (not shown) in a conventional manner. 
     First and second ends of the energy absorber  16 , e.g., a first end being an end of the first piece  17 , and a second end being an end of the second piece  18 , are attached to respective first and second ends of the bumper  14 . For example, pivot pins  22  may be inserted through respective securing tabs  34  in the first and second ends of the energy absorber  16 , and through openings provided in the bumper  14 , thereby pivotably securing each of the pieces  17 ,  18  to the bumper  14 . 
     A linear actuator  20 , e.g., a screw-type linear actuator or the like, is provided to move the energy absorber  16  with respect to the bumper  14 , e.g., to move the energy absorber  16  from a first state to a second state as described above. That is, the actuator  20  may be used to extend the energy absorber  16  away from the bumper  14  to achieve the first state, i.e., deployment for an LSD scenario. Further, the actuator  20  may be used to pull the energy absorber  16  toward the bumper  14  to achieve the second state, i.e., deployment for a pedestrian protection scenario. The actuator  20  includes a bumper securing fixture  23  that may be welded, adhered, or otherwise secured to the bumper  14 . Further, the actuator  20  is connected to the energy absorber  16 , generally to both pieces  17 ,  18 , by a flexing mechanism that allows the actuator  20  to accommodate flexing and movement of the pieces  17 ,  18  with respect to each other and to the bumper  14 . In the present example, the flexing mechanism is a hinged head bracket  26 . The bracket  26  may be secured to the energy absorber  16  with an adhesive or other securing mechanism. 
     As seen in  FIG. 4 , a piece  17  of the energy absorber  16  may include tabs  34  having an opening  36  therein to accommodate the pin  22 . Note that, although one tab  34 , and opening  36 , is shown extending from a top side of the piece  17  in  FIG. 4 , it should be understood that a second corresponding tab  34 , including a second opening  36  in the second tab  34 , generally likewise extends from a bottom side of the piece  17 , the second opening  36  also accommodating the pin  22 . The opening  36  may be elongate, e.g., having a width slightly larger than a diameter of the pin  22 , and having a length some multiple, e.g., 3 to 4 times, the diameter of the pin  22 . The purpose of providing the opening  36  with an elongate shape is to allow the piece  17  to pivot about the pin  22 , and to move in a longitudinal direction with respect to the bumper  14 , when the energy absorber  16  is transitioned from a first state to a second state (or some state in between). 
     For example,  FIG. 4  shows the energy absorber  16 , including the piece  17 , in a first state corresponding to  FIG. 2 . When the linear actuator  20  is actuated to move the energy absorber  16  in a direction toward the bumper  14 , the energy absorber  16  transitions to the second state, corresponding to  FIG. 3 . In this transition, the piece  17  moves in a direction indicated by the arrow A. 
       FIG. 5  shows the energy absorber  16 , including the piece  17  in a second state corresponding to  FIG. 3 , e.g., when the actuator has moved the energy absorber  16  from the first state to the second state. Conversely, the actuator  20  could be used to move the energy absorber  16  in the first state away from the bumper  14  to transition to the second state. Although not shown in detailed diagrams such as  FIGS. 4 and 5 , it should be understood that a second piece  18  of an energy absorber  16  may likewise include tabs  34  having openings  36  through which a pin  22  is inserted. Accordingly, in the manner just described, the pieces  17 ,  18  included in the energy absorber  16  may be movably, longitudinally and/or pivotably with respect to the bumper  14 , secured to the bumper  14 . 
       FIGS. 6 and 7  include detailed views of the linear actuator  20  as used in the system  10 . An actuator flange  24  and an actuator threaded cylinder  25  form an actuator bumper fixture  23 . The flange  24  may be affixed to the bumper  14  via a variety of securing mechanisms, e.g., welding or adhesion. An interior of the threaded cylinder  25  is threaded to correspond with threads provided on an actuator screw  21  threaded therethrough. The screw  21  is rotatably secured to a hinged head bracket  26 . For example, the screw  21  could be provided with a lip or flange to secure the screw  21  to an opening in a head bracket center member allowing the bracket  26  to move toward and away from the bumper  14  in a direction of an axis of the screw  21 . 
     Further, the securing mechanism of the screw  21 , as just mentioned, allows the screw to rotate or turn with respect to the center member  32  of the bracket  26 . The bracket  26  is further provided with side members  30  that are hingedly attached to the center member  32  via hinges  28 . The side members  30 , which, along with the center member  32 , may be made of sheet metal or the like, are secured to the pieces  17 ,  18 , respectively using a securing mechanism, e.g., welding. Accordingly, when the actuator  20  is used to affect motion of the energy absorber  16  toward or away from the bumper  14  in a direction of an axis of the screw  21 , the hinges  28  and or flexibility of the center member  30  accommodate movement of the pieces  17 ,  18  with respect to one another. 
     For example, when the energy absorber  16  is moved toward the bumper  14 , the pieces  17 ,  18  may move apart from one another, particularly on a side to which the members  30  are attached. The hinges  28 , possibly along with flexibility in the center member  32 , accommodates a change in a distance, e.g., the distance grows larger, between the two members  30 . Likewise, when the energy absorber  16  is moved away from the bumper  14 , the pieces  17 ,  18  may move toward one another until there is no gap between the pieces  17 ,  18  on a side to which the members  30  are affixed. Thus, the hinges  28  and/or flexibility of the center member  32  can accommodate the change in distance, e.g., the distance grow smaller, between the two members  30 . 
       FIG. 8  is a block diagram of a vehicle bumper control system  100 . The system  100  includes a controller  105  communicatively coupled to one or more actuators  115 . The controller  105  generally includes a processor and a memory, the memory storing instructions executable by the processor. Further, the controller  105  may communicate on an in-vehicle network and/or communications mechanism, such as a controller area network (CAN) or the like. Accordingly, in addition to one or more actuators  115 , the controller  105  may be communicatively coupled to one or more speed sensors  110 . A speed sensor  110  may be any one of a number of known mechanisms for providing an indication of vehicle speed to the controller  105 , e.g., as a CAN communication or the like. The actuator  115  shown in  FIG. 8  is a generic representation of an actuator used to effect a change in an energy absorber system  10 , e.g., the linear actuator  20  discussed above. 
     A process executed according to instructions stored in the memory of the controller  105  could include a step of, when a vehicle is in motion, using data from one or more speed sensors  110  to determine whether to deploy the bumper system  10  according to a low-speed scenario or a high-speed scenario, e.g., an LSD scenario or a pedestrian protection scenario. For example, a low-speed scenario could be identified when a vehicle was traveling at a speed of 15 kilometers per hour or less, while a high-speed scenario could be identified for any higher speed than this. In any event, upon identifying a scenario, the controller  105  could send a signal, e.g., a CAN communication, to an actuator  115  to move the energy absorber  16  to achieve a desired energy absorbing characteristic of the system  10 . For example, the energy absorber  16  could be moved from a first state to a second state, and/or vice versa, as described above. Accordingly, in the event of an impact, the system  10  would provide appropriate energy absorbing characteristics for a speed of impact. 
     As used herein, the adverb “substantially” modifying an adjective means that a shape, structure, measurement, etc. may deviate from an exact described geometry, distance, measurement, etc., because of imperfections in materials, machining, manufacturing, etc. 
     In the drawings, the same reference numbers indicate the same elements. Further, some or all of these elements could be changed. Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. 
     Many embodiments and applications other than the examples provided would be apparent to those of skill in the art upon reading the above description. The scope of the invention should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the arts discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the invention is capable of modification and variation and is limited only by the following claims. 
     All terms used in the claims are intended to be given their ordinary meaning as understood by those skilled in the art unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.