Modeling of Electrical Igniters of Vehicle Occupant Restraint Systems for EMC Simulations

Electrical igniters of vehicle occupant restraint systems can be activated by electrical pulses or high frequency currents caused by electromagnetic fields. In order not to perturb unintentional ignition of the propellant charge and a releasing of the Airbags or the seat belt tightener in the vehicle, the igniters are always qualified with special ESD and RF immunity tests in the development process. Protection concepts against ESD may not affect the safe function of the restraint systems in case of a vehicle crash. Simulations make a fast examination of several test concepts possible and allow checking of parametrical influences in detail. A thermal electrical model of an igniter was developed and verified on the basis of laboratory measurements. The calculation results show a good agreement with measurements. Different configurations were examined and fundamental relations were represented.