Ignition Coil
The ignition coils are installed in the cylinder head covers, under the Noise, Vibration and Harshness (NVH) covers. Each ignition coil locates on a spark plug and is secured to the related cylinder head cover with a single screw. Each ignition coil incorporates a 3 pin electrical connector for connection to the engine wiring harness.
Each ignition coil contains a primary and a secondary winding. The primary winding receives electrical power supply from the Powertrain Control Module (PCM) relay in the rear Engine Junction Box (EJB). A power stage in the primary winding allows the PCM to interrupt the power supply. The power supply interruption inducing a voltage in the secondary winding and thus the spark plug.
A diode in the ground side of the secondary winding reduces any undesirable switch-on voltage, to prevent misfiring into the intake manifold.
The power stage limits the following voltages:
- the maximum voltage and current in the primary winding.
- the current voltage in the primary winding, to protect the power stage.
- the voltage in the secondary winding.