Abstract:
An outer bumper and an inner bumper have disposed therebetween a plastic bolster. At least one inflator is communicatively coupled to a controller and arranged to inflate the plastic bolster. The bolster is formed of a plastic having sufficient rigidity to fold. In one example, the bolster includes accordion folds in an undeployed state.

Description:
BACKGROUND 
     Equipping vehicles to enhance pedestrian safety has been a subject of growing interest in recent years. Unfortunately, existing pedestrian protection systems require vehicles to include bulky and unwieldy energy absorbing materials at a front end of a vehicle to protect a pedestrian in the event of an impact. For example, energy absorbing materials that are presently used are typically closed or open cell foam, or injection or blow-molded plastic. Because present materials are static, they are required to be thick enough to absorb the impact of the pedestrian, therefore limiting the flexibility of the design of the vehicle&#39;s front fascia and overhang. 
    
    
     
       DRAWINGS 
         FIG. 1  is a perspective view of a vehicle including an exemplary bumper bolster system. 
         FIG. 2  is a top sectional view of an exemplary bumper bolster system with a bolster in an undeployed state. 
         FIG. 3  is a top sectional view of an exemplary bumper bolster system with a bolster in an deployed state. 
         FIG. 4  is a front view of an exemplary bumper bolster system. 
     
    
    
     DESCRIPTION 
     As illustrated in  FIG. 1 , a vehicle  10 , e.g., an automobile, light truck, etc., may include a bumper bolster system  12 . Turning to  FIGS. 2-4 , the system  12  includes an inflatable bolster  14  situated in an interior bumper space  15  between an outer bumper cover  16  and an inner bumper  18 . The bolster  14  generally has a length L, and a height H, dimensioned for the bolster  14  to fit within a space between the bumpers  16 ,  18 . Further, a width W 1  of the bolster  14  in an undeployed, folded position, as discussed below, is determined by a distance between the bumpers  16 ,  18  when the system  12  is in the undeployed state. A width W 1  of the bolster  14  in a deployed position, as also discussed below, is generally two to three times the width W 1 . 
     The inner bumper  18  may be mounted to a vehicle  10  frame or bumper beam  25  in a known manner. The bolster  14  is generally affixed to the bumpers  16 ,  18  with respective welds  20 ,  22 . For example, the bolster  14  is generally made of a plastic, e.g., polypropylene or the like, e.g., some other resinous material, which may be welded to the bumpers  16 ,  18  in a known manner. Use of plastic for the bolster  14  advantageously allows for benefits that cannot be achieved with other materials. In particular, plastic allows for the bolster  14  to be expandable, yet at the same time is sufficiently rigid to be foldable in an accordion-like fashion, and to be securely mounted in the interior bumper space  15 , and to remain properly positioned to expand the space  15  upon inflation. 
     Further, such welds  20 ,  22  may be used to seal seams of the bolster  14 , and/or seams of the bolster  14  may be sealed at other locations. Moreover, although a single weld  20  is shown attaching the bolster  14  to the bumper  16 , the weld  20  need not be continuous along a side of the bumper  16 , but multiple welds  20  could be provided. Likewise, multiple welds  22  could be provided affixing the bolster  14  to the inner bumper  18 . In any case, it is important that the bolster  14  is hermetically sealed to allow for inflation of the bolster  14  by gas from inflators  24 , and that the bolster  14  is securely affixed to each of the bumpers  16 ,  18 . In general, a hermetic seal of the bolster  14  may be achieved by the weld  20  to the outer bumper  16 , with the inner bumper  18  providing a reaction surface for the bolster  14 . It is also possible that one of the welds  20 ,  22  could be omitted. 
     One or more inflators  24  is disposed within the bolster  14 , the inflators being communicatively coupled with a controller  26 , e.g., via wires, a wire harness, and/or a vehicle  10  communications bus, etc., wires or other communications mechanisms being sealed by the weld  22 . Although the bolster  14  is not an airbag, and is made of plastic, as mentioned above, rather than cloth or material typically used for an airbag, inflators  24  may be airbag inflators or the like, i.e., mechanisms for providing an inflation gas to the bolster  14 . 
     Further, controller  26  may be an airbag controller or the like such as is known for detecting a collision or imminent or likely collision, and providing a signal to the inflators  24  to provide the inflation gas. In any case, the controller  26  generally includes a processor and a memory, the memory storing instructions executable by the processor. Further, the controller  26  generally is in communication with various vehicle  10  systems, e.g., via a vehicle communications bus such as a controller area network (CAN) bus or the like. For example, as is known, various sensors such as cameras, radar, lidar, etc., may be used to provide information to the controller  26 , from which the controller  26  determines that a pedestrian collision is imminent or occurring. 
     As seen in  FIG. 2 , the bolster  14  includes corrugated sides to accommodate folding in an accordion-like fashion in an undeployed state. As seen in  FIG. 3 , when the controller  26  detects a likely or actual collision with a pedestrian, the controller  26  triggers the inflators  24 , thereby inflating the bolster  14 , which expands, e.g., as permitted by the accordion folds. In one embodiment, inflation of the bolster  14  increases a distance between the bumpers  16 ,  18  by a factor in a range of about two to three, i.e., as mentioned above, the deployed width W 2  of the bolster  14  is, in an exemplary embodiment generally two to three times greater than the undeployed width W 1 . However, other ratios of the widths W 1 , W 2  could be used. 
     In any case, in the deployed state, the bolster system  12  is in a full energy-absorption position, and provides for a greater absorption of energy than in the undeployed state, the deployed state providing greater protection to a pedestrian. However, in the undeployed state, the bolster  14  advantageously allows the outer bumper  16  to be closer to the inner bumper  18 , and for the front of the vehicle  10  to have a smaller profile, than is possible with systems using energy absorbing materials permanently mounted in a full energy-absorption position. 
     Because the outer bumper  16  moves away from the inner bumper  18  when the bolster  14  is inflated, the outer bumper  16  and the inner bumper  18  may not be attached to one another. However, if the bumpers  16 ,  18 , are attached, such attachment must be easily detachable or breakable when the bolster  14  is inflated. 
     As used herein, the adverb “substantially” means that a shape, structure, measurement, quantity, time, etc. may deviate from an exact described geometry, distance, measurement, quantity, time, 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. With regard to the components, processes, systems, methods, etc. described herein, it should be understood that these are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claimed invention. 
     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 plain and ordinary meanings as understood by those skilled in the art unless an explicit indication to the contrary in 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.