Exhaust Emissions System - Exhaust Gas RECIRCULATION: Description
The exhaust gas recirculation system is designed to control formation of NOx emissions. This is done by reintroducing some exhaust gas back into the combustion chamber. The exhaust gases are lower in temperature than the combustion flame. By reducing combustion chamber temperatures, NOx formation is reduced.
Systems consist basically of an EGR valve, EGR solenoid, thermal switch, electric vacuum switch, transmission switch, vacuum (amplifier) control valve, and EGR maintenance indicator. When 4th gear is selected, the transmission switch activates the EGR solenoid which shuts off vacuum flow and stops EGR operation.