Ignition system utilizing a saturable-core square wave oscillator circuit

Claim 1

In an ignition system for use with an internal combustion engine having breaker points associated therewith for mechanically determining the timing of initiation of an ignition spark for a cylinder of said engine, wherein said system comprises a saturable-core square wave oscillator having a fundamental oscillator frequency and employing a saturable-core transformer to provide electromagnetic feedback coupling and providing relatively high frequency electrical energy having continuing duration during oscillation thereof, means under control of said breaker points for saturating said feedback coupling with steady magnetic flux to stop said oscillator and for cutting off such flux to cause rapid starting of said high frequency energy, an output transformer having a high turns ratio for supplying energy to said ignition spark, a pair of transistors, and circuit means for connecting said transistors to said electromagnetic feedback coupling and to said output transformer, the improvement comprising said output transformer being tuned to resonate at a harmonic frequency of said fundamental oscillator frequency at no load, and the magnetic properties of said saturable-core transformer Being determined so as to cause an increase in the frequency of said oscillator as the load on said output transformer increases.