Ignition System: Description and Operation

Fig. 6 Ignition Control System.:

When the ignition key is turned on voltage is present at the primary windings of both the leading and trailing ignition coils. The current to the primary windings of the ignition coils is interrupted by leading and trailing electronic control modules (igniters) causing the magnetic field surrounding the primary and secondary windings of the ignition coils to collapse inducing a voltage in the secondary windings which fires the spark plugs.

The timing of spark is based on the position of the crank angle sensor. The signals from the two crank angle sensor pickup coils are fed to a control unit which performs the distributor function including spark advance as required.

The leading and trailing spark plugs are fired in a one-two sequence resulting in more complete and efficient burning of the combustion charge thereby reducing emissions.