Electronic ignition control systems

Claim 1

An electronic ignition control system for an internal combustion engine comprising: timing pulse means for generating a plurality of timing pulse signals the interval between successive ones of said pulse signals corresponding to each of successive rotations of said engine; clock means for generating a plurality of clock pulses proportional to actual time; counting means connected to said timing pulse means and said clock means for measuring the number of said clock pulses between successive ones of said timing pulse signals, said number representing the actual speed of rotation of said engine for the preceding revolution thereof, said counting means including means for storing said measured number; a read-only memory containing a plurality of constants corresponding to the differences between the time a spark is generated in a cylinder of said engine and the time at which the flame generated by that spark has been propagated throughout the cylinder, each of said constants being correlated with a predetermined range in the speed of rotation of said engine; calculating means for reading out one of said constants from said memory corresponding to the measured number stored in said counting means at a given time, and calculating from said measured number and said correlated constant, a value representing the time at which the next succeeding spark should be generated in a cylinder of said engine; latch means connected to said calculating means for temporarily storing said value; comparator means connected to said latch means and said counting means for comparing the number of said clock pulses occurring since the last of said timing pulse signals with the value in said latch means, and for producing a coincidence pulse when the number of clock pulses and the value coincide; and buffer means connected to said comparator means and responsive to receipt of said coincidence pulse for generating an output signal to create a spark in a cylinder of said engine.