Continuously variable valve timing system and method for controlling the same

Abstract

A continuously variable valve timing (CVVT) system which may be operated in cooperation with a continuously variable valve lift (CVVL) engine may be included. A reference position of a suction CVVT may be set by a spring. In addition, a method for controlling a continuously variable valve timing (CVVT) system may be included. The method includes setting a reference position of a suction CVVT to a most advanced angle position, and controlling a delayed angle amount at the reference position of the most advanced angle.

1 . A continuously variable valve timing (CVVT) system which is operated in cooperation with a continuously variable valve lift (CVVL) engine, wherein a reference position of a suction CVVT is set by a spring. 
     
     
         2 . The continuously variable valve timing (CVVT) system of  claim 1 , wherein the spring is adapted such that a suction cam timing is shifted in an advanced angle direction when an oil control valve installed in the CVVT system does not operate. 
     
     
         3 . A method for controlling a continuously variable valve timing (CVVT) system which is operated in cooperation with a continuously variable valve lift (CVVL) engine, comprising the steps of:
 setting a reference position of a suction CVVT to a most advanced angle position; and   controlling a delayed angle amount at the reference position of the most advanced angle.   
     
     
         4 . The method according to  claim 3 , wherein when an oil control valve installed in the CVVT system does not operate, a suction cam timing is shift in an advanced angle direction by a bias spring which is installed in the CVVT system. 
     
     
         5 . The method according to  claim 3 , wherein when the oil control valve installed in the CVVT system operates to the max, the oil control valve changes an oil pressure passage connected to the CVVT system.