VALVE DUTY DIFFERENTIATED EXHAUST GAS RECIRCULATION CONTROL METHOD AND EXHAUST GAS RECIRCULATION SYSTEM

An exhaust gas recirculation (EGR) control method includes a valve duty differentiated control including: detecting, by a controller, an engine operation region, a mixer region, and an external factor region as a valve control condition for an EGR valve duty correction variable for controlling an EGR system; applying, by the controller, the EGR valve duty correction variable to an EGR valve duty, which is set by a target air amount to an intake air amount, to calculate a minimum EGR valve duty; and outputting, by the controller, the calculated minimum EGR valve duty to an EGR valve as the EGR valve duty.