Engine control event timing employing both crank angle rotation and time

Abstract

An engine control method generally applicable to those control systems of the engine such as an ignition system, fuel injection system, etc., which are controlled to optimum operation in accordance with engine operating conditions. Angular pulses are generated each time the output shaft of the engine rotates a predetermined angular amount. These angular pulses are counted from the occurrence of a position pulse which is generated at a predetermined angular position of the output shaft of the engine. A central processor is employed to calculate a first angular position at which an electric device for the engine is to be controlled. The central processor also calculates a time interval between the first angular position and a second angular position at which one of the angular pulses is to be provided just before the first angular position. When the angular pulse counting reaches a value corresponding to the second angular position, fixed frequency clock pulses are then counted. When the calculated required time interval has passed as determined by counting the fixed frequency clock pulses, the electric device is controlled.