The ignition timing is controlled by an electronic control system. The values of the optimal ignition timing for all engine operating modes are recorded in the memory of the electronic engine control unit (ECM).
Engine operating mode (engine speed, load, engine thermal condition, etc.) determined by the signals of various sensors. Based on the signals from the sensors and data on the optimal ignition timing, the electronic engine control unit (ECM) sends a signal to interrupt the current in the primary winding of the ignition coil to the power transistor.
A high voltage is induced in the secondary winding of the ignition coil, sufficient to spark between the electrodes of the spark plug, and thus the ignition timing is optimally controlled.