A pair of marker signals are generated with respect to a predetermined crankshaft position; the leading edge of the marker signal is used as a control edge to generate, by digital calculation, a digital control signal calculated in accordance with engine operating characteristics, as related to speed, loading, and the like, and providing a numerical output value used as a control value to control the timing of a pulse which may, depending on use, control: ignition timing; fuel injection timing; transmission gear shifting, the data relating engine performance, with respect to loading, speed, and other parameters such as temperature, starting conditions, and the like, being stored in a data memory. Calculation of the digital control signals and determination, by timed sequential counting out, are carried out independently from each other and during time overlap. Under starting, or emergency condition, an override can be provided coupling the trailing flank of the marker signal -- occurring, for example, at upper dead-center position of the cylinder -- to the output of the system to provide directly generated ignition pulses.