Method for verifying CVVD location learning result and CVVD system thereof

A continuously variable valve duration (CVVD) system, comprising:

• a controller configured to:
• determine, by a data input unit of the controller, whether a learning value acquired in a short duration and a long duration of the CVVD system is required to be verified;
• determine, by a CVVD learning map of the controller, whether the acquired learning value should be verified based on conditions of each of a CVVD system hardware abnormality, a learning value abnormality, and a motor voltage abnormality, wherein a learning value verification control is performed when all of the conditions are not satisfied;
• and
• perform the learning value verification control by comparing a position of a stopper of a control shaft connected to a motor with a cam shaft rotation value, generated by a first protrusion or a second protrusion of a cam shaft during a rotation of the cam shaft, wherein the cam shaft rotation value is detected by an auxiliary cam sensor by detecting the rotation of the cam shaft by recognizing the first protrusion or the second protrusion of the cam shaft,
• wherein the learning value verification control is divided into a long position verification control and a short position verification control, and wherein in the long position verification control a cam shaft rotation value detected by the auxiliary cam sensor is applied to a first threshold, and wherein in the short position verification control a second threshold is applied to the cam shaft rotation value detected by the auxiliary cam sensor;
• a cam sensor provided at an end portion of the cam shaft;
• an auxiliary cam sensor positioned at a middle portion of the cam shaft;
• and
• a CVVD learning verification map configured to provide a signal indicating whether a hardware abnormality, a learning value abnormality, or a motor voltage abnormality is present in the CVVD system.