System and method for controlling valve timing of continuous variable valve duration engine

A system for controlling valve timing of a continuous variable valve duration engine, the system comprising:

• a data detector configured to detect data related a running state of a vehicle;
• a camshaft position sensor configured to detect a position of a camshaft;
• an intake continuous variable valve timing (CVVT) device configured to control an opening timing and a closing timing of an intake valve of the engine;
• an exhaust variable valve duration (CVVD) device configured to control an opening duration of an exhaust valve of the engine;
• and
• a controller configured to classify a plurality of control regions depending on an engine speed and an engine load based on signals from the data detector and the camshaft position sensor, and configured to control operations of the intake CWT device and the exhaust CVVD device according to the control regions;
• wherein the controller retards an intake valve closing (IVC) timing and limits a valve overlap between the intake valve and the exhaust valve in a first control region, advances the IVC timing and applies a maximum duration to the exhaust valve in a second control region, advances the IVC timing according to an increase of the engine load in a third control region, controls a throttle valve to be fully opened and advances the IVC timing in a fourth control region, and controls the throttle valve to be fully opened and retards the IVC timing in a fifth control region.