EGR System - Gasoline: Operation
Exhaust gases flow out of exhaust manifold, through EGR tubes and into EGR control valve. The EGR control valve meters exhaust gas flow in response to vacuum signals received from the vacuum amplifier or solenoid valve.
The vacuum amplifier monitors carburetor ported vacuum and controls vacuum applied at EGR control valve. The water thermo valve, water thermo switch, solenoid valve (and speed switch, if equipped) allow recirculation of exhaust gases under various engine operating conditions.
NOTE:
For illustration of components used by model application, See PISTON ENGINE VACUUM DIAGRAMS article.