New algorithm concept for front crash detection in passenger cars based on measurement of local component-specific loads

Airbag algorithms based on the current state-of-the-art make a decision to fire restraint systems in a crash on the basis of an evaluation of the deceleration of the entire vehicle in the progress of the accident. In order to meet the ever-increasing requirements of consumer test organizations and global legislators, detailed knowledge of the nature and direction of the crash would be of great benefit. The algorithms used in current vehicles are only able to do this to a limited extent. In the context of this work, a completely different measurement method is presented to solve these problems. On the basis of this measurement method a new algorithm approach becomes possible. In addition to vehicle deceleration, the chronological sequence of an accident and the associated local and temporal destruction of the vehicle are possible indicators of the severity of an accident. In order to convert this behaviour into a new algorithm concept, the typical structure of a front end is investigated, and a model for the evaluation of local component-related loads, as an equivalent measurand for the destruction behaviour in the course of a crash, is created. As a result of the investigations, crash intensity is defined as a new evaluation variable for a crash algorithm. On the basis of this new evaluation variable, methods are proposed with the help of which an algorithm can be developed that enables the timely firing of restraint systems for each of the crash load cases under consideration. In addition, algorithms are designed that are able to classify crash load cases and provide information about the direction of the accident. The new algorithms are evaluated on the basis of simulation results, compared with the stateof-the-art, and the effectiveness of the overall algorithm concept is proven in real vehicle tests. In addition to the objects of investigation, the state-of-the-art in the field of vehicle safety, restraint systems and, in particular, the current algorithms in use are presented at the beginning of the work. The current algorithm concepts are classified according to a definition created within the scope of this work. Their advantages and disadvantages are evaluated and compared with the newly developed approach. Finally, an outlook is given on the fields of application of the methodology and on its possible further development. The overall result of the work is the provision of a validated algorithm concept for the timely firing of restraint systems in a crash, with simultaneous classification according to accident type and accident direction.