High efficiency high energy firing rate CD ignition

A capacitive discharge ignition system for internal combustion engines comprising an ignition circuit for firing an ignitor element including at least one energy storage and discharge capacitor of capacitance Cp, and one ignition coil T per ignitor element of primary turns Np, secondary turns Ns, and with turns ratio N=Ns/Np, wherein coil T has a coil primary current switch means S which can be actively turned off, said capacitor Cp, primary winding of said coil T and switch S comprising a primary ignition discharge circuit of Topology Type II wherein said discharge capacitor means Cp is in series with the coil T primary winding, one end of which is grounded, the system powered by an electrical power source Eps for supplying power to the ignition system for charging capacitor Cp to a voltage Vc, the ignition system firing the ignitor to produce ignition sparks in a spark gap in the secondary winding of said coil T by discharging said capacitor means through actuation of said primary current switch means S, the improvement comprising:

• a) a series combination of shunt diode means D and switch SD placed across the coil's primary winding with a voltage dropping element Vdb placed across switch SD,
• b) the system being constructed and arranged for producing an initial capacitive ignition spark discharge, through actuation of switch means S, of duration Tci which can be less than a quarter period of oscillation Tc defined by resonance oscillation of said capacitor Cp with the coil T primary leakage inductance Lpe, said initial discharge followed by an essentially triangular distribution decaying spark discharge of a longer period T which is initiated upon switch S turn-off resulting in diversion of the current flowing in switch S to the series combination shunt diode D and switch SD which is in the turned-on state, and
• c) the system further being constructed and arranged for turning off switch SD near spark current zero or after spark current zero to divert residual primary discharge current through said voltage dropping element Vdb.