Computers and Control Systems: Description and Operation

Fig. 6 Control unit test terminal locations.:

This vehicle uses two control units, Fig. 6. The feedback control unit regulates fuel while the emission control unit controls emission devices.

Fig. 2 Feedback control system components.:

The feedback control system, Fig. 2, is to control the air/fuel ratio to reduce carbon monoxide (CO), hydrocarbons (HC) and oxides of nitrogen (NOx), while minimizing fuel consumption. Various sensors are incorporated which transmit signals to the feedback control unit which processes these signals and varies engine operation accordingly.




The emission control system is used to control such systems as EGR, Evaporative (EEC), and Air Injection .