Exhaust Gas RECIRCULATION: Description

All vehicles are equipped with an exhaust gas recirculation (EGR) system to reduce NOx emissions. With this system, exhaust gas is partially recirculated from an exhaust port of the cylinder head into a port located at intake manifold below the carburetor. Exhaust gas flow is controlled by two EGR valves, one vacuum operated, the other throttle operated. The vacuum applied to the vacuum operated valve is controlled by a thermo valve.