Electronic timing circuit for engine ignition

Claim 1

Apparatus for electronic generation of ignition timing pulses for an internal combustion piston engine having a plurality of pistons respectively operating in a plurality of cylinders to drive a common crankshaft, comprising: means (13) for generating a sequence of pulses corresponding to equal increments of rotation of the crankshaft of the engine such that a multiplicity of pulses is produced during every complete revolution of the crankshaft; counting means (20) for counting pulses of said sequence, including output means having a plurality of binary digit outputs for providing an output representative of crankshaft position with reference to the upper dead-center point of a permanently preselected piston of said engine; evaluation circuit means (25, 50) responsive to outputs of said counting means and also to variations of at least one selected engine operation condition, for providing ignition timing pulses to the ignition system of said engine, said selected engine operation conditions, of which said evaluation circuit means is responsive to at least one, being engine speed, a temperature measured in the engine, and a pressure measured in the engine, said evaluation circuit means containing a circuit having logic connections arranged for detecting when said counting means reaches values of count respectively equal to predetermined angles of rotation of said crankshaft from a position in which said preselected piston of the engine is at its upper dead-center point; and resetting means (10) for resetting said counting means (20) to a count starting condition when said preselected piston of the engine is at its upper dead-center point.