Abstract: Values of a correction amount of correcting a fundamental control amount of an internal combustion engine are stored in a rewritable memory having divisional storage areas corresponding to divisional running areas. When a value of the correction amount for a particular divisional running area is renewed, concurrently therewith, values of the correction amount for divisional running areas adjacent to the particular divisional running area are also renewed.

Abstract: An ignition timing control apparatus for an internal combustion engine having a plurality of cylinders. The apparatus includes a knock sensor for detecting a knocking condition in the engine, sensors for detecting other operating conditions of the engine, a microprocessor unit for receiving signals from the sensors to determine a basic ignition timing of the engine and generate an ignition timing control signal, and a power transistor circuit responsive to the ignition timing control signal from the microprocessor unit to switch on and off the primary current in an ignition coil and generate a high-voltage ignition signal.

Abstract: The data processing unit of an engine control apparatus constantly fetches signals flowing from the sensors and signals flowing to the actuators, and decides whether the respective fetched signals are normal or abnormal to thereby store the results of the decision as diagnosis data in a random access memory.The data processing unit stores a predetermined code in a predetermined area of the random access memory, carries out the engine control data processing operations in accordance with the diagnosis data, and writes the predetermined code in the predetermined area of the random access memory and clears data of all areas of the random access memory other than the predetermined area to thereby carry out the engine control data processing when the read data is determined not to be equal to the predetermined data.