A treatise on crash sensing for automotive air bag systems

Car air bags are effective safety features, but have caused some fatalities and injuries. An essential focus of potential enhancements ("smart air bags") centers around crash sensing. This paper provides a basic yet thorough discussion of underlying technical challenges and design approaches for the subject matter. Mechanical sensors are analyzed to reveal their functioning characteristics. Discussions of design approaches for electronic sensor are elaborated with analysis of sensing algorithms. Subsequently, the shortcomings of current systems are cited. Definitions and compositions of smart air bags are then summarized. Included in the discussions are occupant sensing and integrated systems. Also presented is a perspective on system design of occupant restraints that relates to the concept of energy management. The implementation of air bags and related occupant restraints requires extensive knowledge from various engineering disciplines, in particular mechanical, chemical, electrical, and increasingly electronic expertise. The market is evolving toward a greater usage of electronic contents. The demand of advanced functions is stimulating the integration of various sensing technologies.