Spark plug for igniting Otto engine mixt. - uses HV capacitor discharged on reaching threshold voltage, higher than breakdown voltage of electrodes

摘要

In the igniting process a high voltage capacitor is charged, and discharged across a spark gap and ignition electrodes when a threshold value voltage has been attained. This voltage is higher than the breakdown voltage at the ignition electrodes. The energy transfer takes place in the starting phase of the ignition spark, i.e. possibly in the breakdown phase of the ignition start. In an appropriate spark plug the presparking path is as near as possible to the ignition electrodes. It has the lowest possible ohmic and inductive resistance, and its threshold value voltage is externally controllable. Between the capacitor and the ignition electrodes the inductance and ohmic resistance of the supply line to the electrodes is as low as possible, at least at frequencies exceeding 50 MHz.