Ignition timing control device for internal combustion engine

摘要

An engine operating region in which two ignition plugs ignite at different ignition timings is restricted to a region (phase-difference ignition region) where the effect of different ignition timings is remarkably achieved. In the operating region other than the above region, simultaneous ignition is performed. A basic ignition timing IGMAPIN of the intake ignition plugs 8I is calculated by searching a map (S11). In the phase-difference ignition region, a basic ignition timing IGMAPEX of exhaust ignition plugs 8E is calculated by searching a map (S13). By contrast, in the operating region where simultaneous ignition is to be performed, the basic exhaust ignition timing IGMAPEX is set as the basic intake ignition timing IGMAPIN (S14).