BACKGROUND

Technical Field

The present disclosure relates to an ignition control system that is used in an internal combustion engine.

Background Art

In recent years, to improve fuel efficiency of internal combustion engines for automobiles, technologies related to combustion control (lean burn engines) of lean fuel and exhaust gas recirculation (EGR) in which a combustible air-fuel mixture is circulated to a cylinder of the internal combustion engine are being studied. In these technologies, as an ignition system for effectively burning fossil fuel that is contained in the air-fuel mixture, a multiple ignition system in which a spark plug continuously performs discharge a plurality of times at an ignition timing of the internal combustion engine is sometimes used.

SUMMARY

The present disclosure is an ignition control system that is applied to an internal combustion engine that includes a spark plug, an ignition coil including a primary coil and a secondary coil, a voltage value detecting unit, and a secondary current detecting unit. The ignition control system performs discharge generation control, in which a discharge spark is generated, once or a plurality of times during a single combustion cycle. The ignition control system successively calculates an approximate energy density based on a secondary current and a discharge path length. During a predetermined period after blocking of a primary current is performed during a single combustion cycle, the ignition control system calculates an integrated value by integrating the discharge path length at this time, based on the approximate energy density being greater than a predetermined value. The ignition control system performs the discharge generation control again based on the calculated integrated value being less than a first threshold.

