Pulse generator of the corona discharge type for sensing engine crankshaft angle on an engine control system

A spark timing and exhaust gas recirculation control system for an internal combustion engine, comprising:

• means for producing a signal representative of the amount of exhaust gases recirculated through said engine;
• means for producing a signal representative of the speed of said engine;
• means for generating a first pulse in response to an engine cylinder reaching a reference point of its combustion cycle and second pulses the frequency of which is proportional to the speed of said engine;
• means for producing a signal representative of power which said engine delivers;
• first storage means in which is stored a set of data each representative of the spark timing of said engine cylinder as a function of a set of engine speed and engine power values for generating a corresponding output in response to said signals representative of said engine speed and engine power;
• second storage means in which is stored a set of data each representative of the rate of exhaust gas recirculation as a function of a set of engine speed and engine power values for generating a corresponding output in response to said signals representative of said engine speed and engine power;
• counter means arranged to be preset in accordance with the output from said first storage means for counting said second pulses in response to each said first pulse and generating a spark timing pulse in response to the counted second pulses reaching said preset count value;
• and
• means for comparing said signal representative of the amount of recirculated gases with the output from said second storage means to detect the difference therebetween for regulating said recirculated gases;
• wherein said means for generating first and second pulses comprises a rotor mounted for revolution with said engine and having a plurality of angularly equally spaced apart segmented regions, electrode means stationarily mounted with respect to said rotor to define an air gap with each one of said segmented regions upon rotation of said rotor and connected to a source of DC potential to form a corona discharge through said air gap to successively generate corona discharges across said air gap upon rotation of said rotor, and an impedance element responsive to each of said corona discharges to develop a signal corresponding to said first and second pulses, one of said segmented regions having a different dimension from the dimension of the other segmented regions and being arranged in said rotor to coincide with the path of said corona discharge in response to said engine cylinder reaching said reference point.