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In this paper, we describe some important aspects of crash severity sensing for “smart” airbag implementation. In particular, gray zone considerations are described in detail. Another important issue discussed is the loss of the additional front sensor used for crash severity sensing and its impact on system performance. A third issue of great importance is the second stage (assume a dual-stage inflator) firing delay. Finally, a discussion of some inherent problems with the crash severity sensor approach are discussed as well as dynamic range/resolution problems that accelerometers can encounter when used in the crush zone of a vehicle. A summary with conclusions and recommended approaches is presented.

A new fast combustion inflator based on the reactions of methane-oxygen mixtures has been developed. The performance of this inflator was evaluated in terms of pressure-time relationships inside the inflator and in a receiving tank simulating an air bag and by assessing the temperature-time relationship in the tank. In order to develop this inflator, several critical issues were studied, including stoichiometry, initial mixture pressure and extreme ambient conditions. Other design parameters such as burst disk thickness and type, ignition device, tank purging gas, concentration of carbon monoxide, severity of temperature in the tank, and the inflator size were investigated and optimized. To simulate the behavior of this inflator, a theoretical and integrated model was developed. The experimental results made at different conditions were found to be in agreement with the model.

Although lower extremity injuries are not life threatening (AIS less than 4), they are very debilitating and require long periods of rehabilitation. A possible cause of the ankle/foot injury in frontal crashes is the foot dorsiflexion resulting from intrusion of the toeboard. Ankle injury on the driver side in the same type of crashes may also be caused by the foot eversion or inversion as it slides off the pedals. In both cases, it is believed that bracing the leg is a major contributor to the injury mechanism. Another contributor to lower extremity injuries is leg interaction with the instrument panel (IP). This paper describes an activated seat design that acts to eliminate the interaction between the lower extremities and the vehicle interior. It also reduces the interaction between the legs and the IP by limiting the forward travel of the lower torso. Three different design approaches are presented in the paper.