Capacitor discharge ignition system for internal combustion engine

Abstract From the Canadian patent

The capacitor discharge ignition system for an internal combustion engine includes an ignition capacitor charged by a power supply and discharged through the primary of an ignition coil when a silicon controlled rectifier (SCR) becomes conductive in response to a trigger voltage is applied to the gate of the SCR. A resistor-capacitor delay circuit on the output of the SCR delays rapid discharge of the capacitor to thereby delay the spark at the spark plug in the secondary of the coil. A second SCR is connected to shunt the RC time delay to effectively advance the spark timing in response to predetermined engine speed.