Ignition System: Description and Operation

Electronic Ignition System:

PURPOSE AND OPERATION
The ignition timing is controlled by the Engine Control Module (ECM) in order to maintain the best air-fuel ratio in response to every running condition of the engine.
The ignition timing data is stored in the ECM. This data forms the map shown below.

Ignition Data Map:

The ECM detects information such as the injection pulse width and camshaft position sensor signal which varies every moment. Then responding to this information, ignition signals are transmitted to the power transistor.

In addition to this,

^ At starting
^ During warm-up
^ At idle
^ At low battery voltage

the ignition timing is revised by the ECM according to the other data stored in the ECM.

The retard system, actuated by the knock sensor, is designed only for emergencies. The basic ignition timing is pre-programmed within the anti-knocking zone, even if recommended fuel is used under dry conditions. Consequently, the retard system does not operate under normal driving conditions.
However, if engine knocking occurs, the knock sensor monitors the condition and the signal is transmitted to the ECM (ECCS control module). After receiving it, the ECM retards the ignition timing to eliminate the knocking condition