This paper describes new concepts to detect side impact collisions. Based on the specific system requirements for side impact detection, a new concept is described using the sensing of the pressure change within the cavity of the impacted door during a side impact collision.

Based on this sensing principle, different system configurations will be shown. The sensing principle was analysed in a large variety of different crash and misuse test conditions. In order to understand the physics of pressure signals, a theoretical model was developed. A thermodynamical description will be set up based on adiabatic compressions and the flow dynamics using the Navier-Stokes equation.

In concluding, the sensing principle will lead to timely firing decisions, e. g. which are in most cases less than five milliseconds. The sensing system is capable to decide well between fire and cases, as well as misuse conditions. A theoretical modeling can reproduce the experimental results and thus provides a further understanding of the entire physical process.