Automobile engine ignition timing control - uses accurate digital counters as integration stages

摘要

The timing control uses a pulse generator (10) responsive to the rotation of the crankshaft or the camshaft controlling a pair of integration stages. Each of these comprises a digital counter (11,12) carrying out a continuous count and responsive to different flanks of the pulse generator pulses. The counter (12) responsive to the latter flank counts forwards with a higher count frequency (f2) beginning from a count value (Zp) dependant on an engine operating parameter. The ignition is fired by the output of a comparator (14) provided when both counters (11,12) reach the same count value. The timing control provides a high timing accuracy and readily allows a wide range of ignition setting characteristics to be obtained.