Electronic advance and retard control circuit

Claim 1

nIn an internal combustion engine with a closed loop, regulated shaft angle position signal and shaft angular velocity signal generating system, comprising in combination an adjustable current source, integrating means having an input connected to said adjustable current source, reset means responsive to engine rotation periodically resetting said integrating means at regular spaced intervals of engine rotation to produce a sawtooth-shaped signal related to engine shaft angle position in the output of said integrating means, a voltage reference source establishing the regulation level for said sawtooth signal and having a predetermined relationship to the peak amplitude which the sawtooth signal should attain when said integrating means is reset by said reset means, comparator means connected to said reference source and said integrating means to produce an output signal when the amplitude of said sawtooth signal attains said predetermined relationship to the level of said voltage reference source, and means connecting the output of said comparator means to said adjustable current source for adjusting the latter until the output of said integrating means attains said predetermined relationship to the voltage level of said reference source when the integrator means is reset, said integrating means, comparator means and said adjustable current source connected in a closed feedback loop which automatically and continuously regulates the sawtooth-shaped shaft angle position signal in the output of said integrating means and produces the shaft angular velocity signal in the output of the adjustable current source as a result of the regulation of the shaft angle position signal in the output of said integrating means.