Ignition System Construction

In this ignition system, each cylinder has its own ignition coil with a built-in igniter. The ignition timing is under control of ECM, which receives signals from the CMP, TP, ECT and MAF sensors and determines the ignition timing based on these signals.

Each component operates as described.

• ECM 

  It detects the engine condition by the signals from the sensors, determines the most suitable ignition timing and time for electricity to flow to the primary coil and sends a signal to the igniter (power unit).

• Igniter (Power unit) in ignition coil assembly 

  It turns ON and OFF the primary current of the ignition coil according to the signal from ECM.

• Ignition coil in ignition coil assembly 

  When the ignition coil primary current is turned OFF, a high voltage is induced in the secondary winding. One ignition coil is in charge of ignition of one cylinder only.

• CMP sensor (Camshaft position sensor) 

  Being photoelectrically operated, this system converts timing and time by and during which the light is received at the light receiving part in the CMP sensor into the electric signals. It also outputs the engine speed (position) signal and the cylinder identification (reference) signal to ECM.

• TP sensor, ECT sensor and MAF sensor 
• Knock sensor 

  It uses a piezoelectric ceramics element which converts engine vibration into voltage signals and detects knocking from them. Receiving signals from the knock sensor, ECM controls the ignition timing to prevent knocking.

• TCM (Vehicle with A/T) 

  TCM (Transmission Control Module) sends torque reduction signal to ECM when gear shifting is needed. Receiving the torque reduction signal from TCM, ECM retards the ignition timing during gear shifting in order to reduce shift shock of automatic transmission.