Exhaust Gas Recirculation: Description and Operation

PURPOSE/OPERATION
The EGR system aims at reduction of NOx by lowering combustion chamber temperature through recirculation of a part of exhaust gas into cylinders via the collector chamber. The system consists of an EGR valve, EGR solenoid valve, temperature sensor, and necessary hoses. The EGR valve is operated by throttle body vacuum and controls exhaust gas flow from exhaust manifold to collector chamber. The EGR solenoid valve is controlled by the ECM according to engine operating conditions and opens/closes the vacuum line from throttle body to EGR valve diaphragm.