ALLUMAGE PAR DECHARGE DE CONDENSATEUR AVEC RETARD D'ALLUMAGE AUTOMATIQUE

Disclosed herein is a capacitor discharge ignition system adapted for use with an internal combustion engine and comprising a charge capacitor, an ignition coil primary winding, an ignition SCR, and a spark retard circuit connected in series relationship with the charge capacitor, the primary winding, and the ignition SCR. The spark retard circuit comprises a thyristor having an anode-cathode path connected in series relationship with the charge capacitor, the primary winding, and the ignition SCR, an RC delay network including a capacitor and a resistor with a junction therebetween, the network having one end connected to the thyristor anode and having an opposite end connected to the thyristor gate, and a zener diode connected between the thyristor gate and the RC delay network junction for selectively preventing full discharge of the capacitor through the primary winding for a predetermined period of time after the ignition SCR is rendered conductive, thereby allowing for over advancing at mid rpm range and providing for automatic spark retard at higher engine rpm. In one embodiment of the invention a potentiometer replaces the resistor in the RC delay network to allow for further adjustment of ignition spark timing.