Electronic Ignition (EI) System

Electronic Ignition (EI) System:

SYSTEM DESCRIPTION

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.

Electronic Ignition Timing Map:

The ignition timing data is stored in the ECM, in the form of the map as shown.

OPERATION
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.

e.g. N: 1,800 rpm, Tp: 1.50 msec A BTDC

In addition to this,
1. At starting
2. During warm-up
3. At idle
4. At low battery voltage
the ignition timing is revised according to the other data stored in the ECM.

RETARD SYSTEM

The retard system by 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. After receiving it, the ECM retards the ignition timing to avoid the knocking condition.

Power Transistor:

POWER TRANSISTOR

The power transistor, located on the R.F. frame rail in the engine compartment, is a voltage amplifier that allows the signal sent from the ECM to activate the primary circuit in the ignition coil. This induces high voltage in the secondary windings of the ignition coil, providing spark to the distributor cap and plugs.