Exhaust Gas Recirculation: Description and Operation

The EGR system is used to reduce oxides of nitrogen in the exhaust gasses. Exhaust gas is partially recirculated from an exhaust port at the cylinder head into a port located at the intake manifold below the carburetor. EGR flow is controlled by an EGR control valve, a sub-EGR control valve and a thermo valve. To improve driveability, EGR flow is suspended during idle and wide open throttle operation.