Evoluzione teorico-sperimentale di un sistema di accensione a microonde per i motori ad A.C.

The latest developments of an experimental research concerning an innovative ignition system for S.I. engines are shown. The system is based on free discharge of energy at microwave frequency. It allows to operate with greater amounts of ignition energy without electrode erosion and higher efficiency in energy convey than conventional ignition systems. In fact every single energy discharge is limited to almost the breakdown phase. TMO1O resonance mode is excited inside the combustion chamber. Because of plasma properties, if microwave introduction is prolonged beyond ignition, microwave energy is converted to flame-front electron energy. Thus combustion speed and wholeness are improved, even when mixture conditions are untavourable. A prototype was constructed for experimental tests concerning breakdown produced by microwaves in air at various pressure levels. The results are in good agreement with theory.