Engine control method and engine control device

An engine control device for controlling, based on an operating condition, an ignition timing of each cylinder of an engine having at least three cylinders, the engine control device comprising a processor configured to:

• calculate an ignition timing of each cylinder based on whether or not knocking is occurring;
• set, as a reference ignition timing, at least the ignition timing of a first cylinder of the at least three cylinders, for which the calculated ignition timing is (i) on an advanced angle side relative to a most retarded angle ignition timing on a most retarded angle side and (ii) on a retarded angle side relative to a most advanced angle ignition timing on a most advanced angle side;
• set an allowable timing difference range that is a range of an allowable timing difference with reference to the reference ignition timing;
• determine whether or not the ignition timing of each cylinder falls within the allowable timing difference range;
• and
• when a determination is made that the ignition timing of a second cylinder of the at least three cylinders falls outside the allowable timing difference range, correct the ignition timing of the second cylinder determined to fall outside the allowable timing difference range so that the timing difference of the ignition timing of the second cylinder with respect to the reference ignition timing falls within the allowable timing difference range.