Digital automobile ignition timing control - has counters controlled by rotation rate indicated by sensor responsive to passage of crankshaft disc teeth

摘要

The ignition timing control has a toothed disc (1) attached to the crankshaft with a sensor (3) coupled to a counter (4) for counting the teeth. The ignition angle is obtained from the contents of two counters (22,30) one of which is started by detecting a reference marking carried by the toothed disc (1) and counts the pulses supplied by the first sensor (3), the second counter (30) being started when the first of these two counters has performed its run. This second counter (30) is indexed by a fixed frequency and supplies the ignition signal, a further counter (25) started at the same time supplying an ignition closure signal. Pref. the counters are fed with values from respective stores coupled to respective control outputs of a microprocessor responsive to the engine operating parameters including the rotation rate represented by a counted time interval control by the initial counter coupled to the sensor (3) for the teeth (2) of the crankshaft disc (1).