Ignition Coil: Description and Operation

ENGINE CONTROL COMPONENTS

Coil On Plug (COP)
The COPs are part of the distributorless ignition system. They are the source of the high voltage which is used to generate the spark by the spark plug. The hybrid vehicle uses four COPs, one for each cylinder. The COPs are mounted directly onto the spark plugs. The function of the COP is to convert low voltage into high voltage in excess of 40,000 volts.

The COP consists of primary and secondary windings. The primary winding is energized by the IGN START/RUN circuit. The PCM coil driver circuit is connected to the primary winding as well. The secondary winding is connected to the spark plug. The current flowing through the primary winding generates the magnetic field across both windings. The PCM activates the coil driver circuit by opening it. The instant the circuit opens the magnetic field collapses, inducing current flow in the secondary winding.

The COP has three different modes of operation: engine crank, engine running, and CMP failure mode effects management (FMEM).