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 including a turbocharger, the system comprising:

• a data detector configured to detect data related to 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 opening timing and closing timing of an intake valve of the engine;
• an exhaust two-stage variable valve duration (VVD) device configured to control opening duration of an exhaust valve of the engine in two stages;
• an exhaust continuous variable valve timing (CVVT) device configured to control opening timing and closing timing of the exhaust valve;
• 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 CVVT device, the exhaust two-stage VVD device, and the exhaust CVVT device according to the control regions,
• wherein the controller applies a maximum duration to the intake valve and a long duration to the exhaust valve in a first control region, advances an intake valve closing (IVC) timing, applies the long duration to the exhaust valve, and maintains a maximum valve overlap in a second control region, applies the long duration to the exhaust valve and advances the IVC timing and an exhaust valve closing (EVC) timing in a third control region, applies a short duration to the exhaust valve and controls the EVC timing to be close to a top dead center (TDC) in a fourth control region, controls a throttle valve to be fully opened, applies the short duration to the exhaust valve, and retards an exhaust valve opening (EVO) timing in a fifth control region, and controls the throttle valve to be fully opened, applies the long duration to the exhaust valve, advances the EVO timing, and controls the EVC timing to be close to the TDC in sixth control region.