Ignition System: Description and Operation

Ignition System Components:

SYSTEM OPERATION
To produce a spark that will ignite the air/fuel mixture within an engine's cylinders, ignition systems generate high voltage and direct it to spark plugs at each cylinder. Voltage must be high enough to jump the spark plug gap under compression and it must be supplied at the correct time under a wide range of operating conditions.

SYSTEM COMPONENTS

Crank And Cam Angle Sensors
The crank and cam angle sensors provide the ECU with signals regarding engine rpm and #1 cylinder TDC (camshaft position). Together with other inputs, the ECU calculates ignition timing over the range of vehicle operating conditions. For additional information on these sensors, refer to COMPUTERS AND CONTROL SYSTEMS.

Igniter
An ECU controlled igniter is used to regulate current flow through the coil primary circuit. Each time current flow is interrupted, high voltage is induced to fire the spark plugs. Except for the initial setting, timing is determined by the ECU.

Secondary Ignition Components
Ignition wires direct high voltage from the distributor and coil to the appropriate spark plug.