EGR System: Description

The exhaust gas recirculation (EGR) system is used to help control formation of NOx emissions. By recycling a limited amount of exhaust gas back to the intake system, combustion temperatures are lowered, which helps keep NOx emissions down.

The system consists of EGR valve, EGR pipe, thermostatic valve, control valve orifice and vacuum outlet.

The EGR system operates differently for non-turbo and turbo, but the thermostatic valve, which deactivates the EGR system below 112°F (43°C), is controlled by coolant temperature in both systems.