Method for verifying CVVD location learning result and CVVD system thereof

A method for verifying a continuously variable valve duration (CVVD) location learning result, comprising the steps of:

• determining, by a controller comprising a data input unit, whether a learning value acquired in a short duration and a long duration of a CVVD system is required to be verified;
• determining, by the controller based on a continuously variable valve duration (CVVD) learning map, 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 the conditions are not satisfied, and
• performing the learning value verification control by comparing, by the controller, 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.