Capacitive discharge ignition system

Claim 1

A capacitive discharge ignition system for use with an internal combustion engine having a power source and means for producing timed pulses for triggering the ignition system comprising, in combination, a storage capacitor, a voltage stepup transformer having primary and secondary windings mounted on a core, a controlled conduction device having input, output and control electrodes, means connecting said primary winding, said input electrode and said output electrode in series, means for connecting said series connected transformer and controlled conduction device to the power source, means connected to said control electrode responsive to each trigger pulse for switching said controlled conduction device to a conducting state whereby current flows from the power source through said primary winding and said controlled conduction device to store energy in said transformer core, first means connected to said control electrode responsive to an increasing current flow through said series primary winding and controlled conduction device for increasing the impedance of said controlled conductIon device to limit current flow through said controlled conduction device to a predetermined maximum level whereby the total energy stored in said core is regulated, second means responsive to the voltage across said primary winding dropping to a predetermined minimum as the current through said primary winding increases to said predetermined maximum level for switching said controlled conduction device to a nonconducting state whereby a collapsing magnetic field in said core establishes a predetermined high voltage across said secondary winding, means for charging said capacitor with such secondary voltage, means responsive to each trigger pulse for discharging said capacitor, and means responsive to the discharge of said capacitor for generating a high voltage for firing a spark plug.