The electronically controlled EGR system consists of an EGR valve, engine-ECU and sensors. The EGR valve aims at reducing the amount of NOx (nitric oxide) discharge that increases
with the rise in the exhaust gas temperature. Thus, the engine-ECU optimally controls the exhaust
gas temperature in accordance with the operating conditions of the engine. To further improve the exhaust gas reduction performance, the system provides the engine-ECU feedback
on the EGR valve opening. Thus, it effects EGR control to optimize the operating conditions
of the engine.