Ignition System: Description and Operation

GENERAL INFORMATION
Ignition timing is controlled by the electric control ignition timing system. The ignition timing data for the engine operating conditions are programmed in the memory of the engine control module (ECM).

The engine conditions (speed, load, warm-up condition, etc.) are detected by the various sensors. Based upon these sensor signals and the ignition timing data, signals to interrupt he primary current are sent to the power transistor. The ignition coil is activated, and timing is controlled at the optimum point.

*CKP: Crankshaft Position
*CMP: Camshaft Position

With the ignition switch in the ON or START position, battery voltage is applied to the ignition coils. As the crankshaft turns, the engine control module (ECM) receives the signals of CKP and CMP sensor. Based on these inputs and other engine sensors, the engine control module (ECM) controls the current through the ignition coil by turning the power transistor (built-in ignition coil) on and off.

When current flow through the primary winding is stopped, a high voltage is induced in the secondary winding of the ignition coil. The high voltage is applied to the two spark plugs that are connected in series.

The ignition failure sensor is connected between the ignition coil fuse and ignition coils to detect ignition failure.