PURPOSE: To adjust the ignition timing always to MBT and perform the efficient ignition in consideration of the knock limit by calculating the time difference between MBT (Minimum Spark Advance for Best Torque) and the ignition timing and correcting the ignition timing in this case from the obtained time difference.
CONSTITUTION: An electronic controller 6 inputs a variety of detection signals supplied from a variety of sensors 13-17 and 21 for detecting the operation state of an engine 100, into an input interface 9. While, each control signal is outputted into a fuel injection valve 5 and a spark plug 18 from an output interface 11. In this case, an electric power source 24 for bias for measuring the ion electric current through a high voltage diode 23 is connected with the spark plug 18. An electronic control means 6 allows the ion electric current to flow in a cylinder 10 immediately after ignition, and the time when the electric current value becomes max. is measured. The time difference between the measurement time and the MBT position is calculated, and the time difference is added and subtracted for the ignition time in the preceding time, and the ignition timing in this case is determined.
TAKAGI SADAO
KAJITANI KATSUYUKI
