Ignition timing controlling device and method

Abstract

A method of controlling ignition timing of an engine. In the control method, final ignition timing for performing ignition is calculated by adding a variation component to a set ignition timing. According to the final ignition timing, an indicated average effective pressure of an in-cylinder pressure detected when ignition is performed is calculated. An ignition timing characteristic curve indicating the correlation between the indicated average effective pressure and the variation component is estimated and optimal ignition timing is calculated from the characteristic curve. Feedback control for converging the set ignition timing to the optimal ignition timing is then performed. Consequently, the ignition timing is controlled to an optimal ignition timing corresponding to a current operational state of the engine.