Oscillatory–Discharge Processes in Capacitive Ignition Systems with a Unipolar Pulse

Abstract

The discharge processes in a capacitive ignition system with a unipolar pulse, which offers advantages as compared with ignition systems of oscillatory discharge, are investigated. It is noted that the received wisdom concerning the dynamics of development of a unipolar discharge pulse is rather conditional. It is shown that, for small values of inductance of discharge circuit, the discharge in the plug becomes oscillatory, with a pronounced oscillating component being superimposed onto the aperiodic component of the current. An experimental setup and a technique for investigating the oscillatory discharges when changing the parameters of the discharge circuit including the storage-capacitor capacitance and the inductances in the circuit of a shooting semiconductor plug and in the circuit of a high-voltage diode are described. The results of oscilloscope experimental studies and an analysis of results of measuring of the energy of spark discharges in the shooting semiconductor plug are presented depending on the parameters of the discharge circuit. The regularities of development of oscillatory discharges are laid out. It is shown that oscillatory discharges are generated not only under small inductances of the discharge circuit, but also when increasing the inductance in the case of connecting an additional inductance, the value of which is lower than the value of the main inductance, to the high-voltage diode circuit. It is proved that the energy efficiency of the capacitive ignition system of oscillatory discharge can exceed the efficiency of modern ignition systems with a unipolar pulse.