Abstract
Rapidly evolving active safety sensing systems may be able to predict an imminent crash with growing accuracy and reliability, thus complementing with the passive safety sensing systems in a vehicle. As a result, during a pre-crash braking maneuver, with help of new types of restraint systems, the vehicle occupants may be able to change their posture and velocity relative to vehicle interior so as to mitigate the effect of crash. The primary objective of this study is to explore the ability of pre-crash deployment of the motorized retractor pretensioner to control occupant motion just prior to collision and to reduce occupant injury risk. The secondary objective is to carry out a feasibility study for the scope of replacing the conventional pyrotechnic pretensioner with a motor-powered pretensioner (MPP) and identification of the MPP characteristics necessary for adequate occupant restraint. In this paper, shoulder belt pre-crash pretensioning is found to reduce the forward excursion of the model occupant’s head and chest as well as occupant loading. The outcome of the study also shows the potential of high-powered motorized seat belts to replace pyrotechnic retractors. Such replacement, however, would require a much broader analysis as well as a major shift from current typical pretensioner design and performance.