Future legislation in Japan and European countries may require an energy absorbent design for a vehicle bumper system to help protection a pedestrian's legs from an impact.
Current bumper impact systems employ several separate components, which are assembled. Generally, these components include a soft energy absorber backed by stiff reinforcing beam to achieve US FMVSS and European ECE42 impact. The component parts of the energy absorber may be a thermoplastic resin or polypropylene foam adjacent a stiff supporting reinforcing beam of steel or aluminum. The bumper assembly typically includes a reinforcing beam, which is configured to attach to vehicle rails, an energy absorber, and an aesthetic fascia attachable to the energy absorber. The fascia typically substantially envelops both the reinforcing beam and energy absorber.
Traditional vehicle bumper and bumper energy absorber systems have been designed to protect vehicle structures and possibly occupants of the vehicle during low speed, about 5 miles per hour (mph), in a vehicle-to-vehicle or vehicle-to-solid structure impact. The new legislation requires a level of pedestrian protection during impact with the front end of an automotive vehicle. The impact energy levels during such an occurrence are much lower than the traditional 5 mph vehicle bumper impacts. Systems designed for 5 mph vehicle bumper impact are maybe too stiff to provide a sufficient level of pedestrian injury mitigation.
Desirable features of bumper systems include adaptability of the system to provide for US FMVSS 5 mph impact requirements, European ECE42 legislation, Allianz impact requirements and European Pedestrian Protection for lower and upper leg or legs.