Multiple spark cd ignition system

Abstract

Disclosed herein is a multiple spark circuit for use with a capacitor discharge ignition system including a current supply, a charge capacitor, an ignition coil primary winding, and an ignition timing SCR. The multiple spark circuit includes a charge reservoir capacitor connected to the current supply, a restrike circuit subject to the timing SCR, and to the voltage and discharge current of the charge capacitor, for allowing repeated charging and discharging of the charge capacitor to produce multiple ignition sparks at each ignition timing point, and a charge interrupt circuit, subject to the restrike circuit, for allowing repeated charging of charge capacitor by the charge reservoir capacitor at each ignition timing point. The restrike circuit preferably comprises a thyristor connected to the timing SCR and charge capacitor, and a zener diode connected to the thyristor gate and anode to render the thyristor conductive when the charge capacitor voltage exceeds a predetermined upper limit. The charge interrupt circuit preferably includes a Darlington transistor connected between the charge reservoir capacitor and the charge capacitor, with the base connected to the current supply and to the ignition coil primary winding, whereby, when the charge capacitor is discharging, the base current is shunted to interrupt charging of the charge capacitor by the charge reservoir capacitor.