Exhaust Gas Recirculation: Description and Operation

PURPOSE / OPERATION
- The Exhaust Gas Recirculation (EGR) system aims at reduction of Oxides of Nitrogen (NOx) by lowering the combustion temperature through recirculation of a part of exhaust gas into cylinders via the intake manifold.
- This system consists of the EGR valve, EGR solenoid valve, and Back Pressure Transducer (BPT): The EGR valve is operated by the vacuum via a BPT from the throttle body and controls the exhaust gas flow from the exhaust manifold to the intake manifold. The EGR solenoid valve is controlled by the ECM according to the engine driving condition and opens/closes the vacuum line from the BPT to the EGR valve diaphragm. The BPT controls vacuum in order for the amount of the EGR that corresponds to the engine load to be obtained.