Ignition System: Description and Operation

CIS-EIII Ignition Components:

CIS-EIII (Bosch KE3-Jetronic) Engine Control System:

The CIS-E III engine control system is a mechanical, continuous injection system which is electronically controlled. The system is based on the Bosch KE-Jetronic fuel injection system. Two separate electronic control units (ECUs) are used. One controls the fuel delivery while the other controls the ignition system. The ECUs share information from various engine sensors and use this information, compared with information stored in their individual memories, to precisely control the fuel and ignition systems for lower exhaust emissions, better fuel economy and better engine performance, under all operating conditions.
Ignition control is managed by the ignition control unit, through signals to a power switching transistor (power output stage) that operates the ignition coil. The signal timing (ignition timing) and duration (dwell) is determined by inputs from the coolant temperature sensor, hall sensor, air flow sensor potentiometer, and knock sensor mounted on the engine.
Only the output devices and secondary ignition components are covered in this section. For complete information on computer control of the ignition system and the sensors and signals that influence it, refer to COMPUTERS AND CONTROL SYSTEMS.