METHOD OF REDUCING OF NOX OF GDI ENGINE FOR VEHICLE

摘要

PURPOSE: An NOx reduction method of a GDI(Gasoline Direct Injection) engine is provided to reduce NOx deposited on a lean NOx reduction catalyst when driving an engine at an area of lean air-fuel ratio. CONSTITUTION: An NOx reduction method comprising the steps of: deciding if the measured value of NOx in the exhaust gas is over a predetermined value when driving an engine; performing a normal driving without suspending ignition if the measured value is not over the predetermined value; suspending the ignition at a lean fuel area; reducing NOx deposited on a lean NOx reduction catalyst by radiating the injected fuel; and removing NOx repeatedly until the engine stops after reducing NOx. Herein, the function of NOx catalyst is maintained at a lean fuel area and the fuel efficiency is improved at an abnormal driving area without backing in normal ignition time.