Engine that is equipped with continuous variable valve lift system

Abstract

An engine having a continuously variable valve lift system, may include a camshaft having an input cam formed at one side thereof, wherein the camshaft is mounted on a cylinder head, a drum shaft that is disposed with a predetermined distance from the camshaft, wherein a swing arm is rotatably mounted at one side thereof, a control shaft that is disposed with a predetermined distance from the drum shaft, wherein a control cam that varies a position of the drum shaft is formed thereto, an output cam that is rotatably mounted on the camshaft and is connected to and moved by the swing arm, such that the output cam variably lifts a valve mounted in the cylinder head according to a position of the drum shaft,

1 . An engine having a continuously variable valve lift system, comprising:
 a camshaft having an input cam formed at one side thereof, wherein the camshaft is mounted on a cylinder head;   a drum shaft that is disposed with a predetermined distance from the camshaft, wherein a swing arm is rotatably mounted at one side thereof;   a control shaft that is disposed with a predetermined distance from the drum shaft, wherein a control cam that varies a position of the drum shaft is formed thereto;   an output cam that is rotatably mounted on the camshaft and is connected to and moved by the swing arm, such that the output cam variably lifts a valve mounted in the cylinder head according to a position of the drum shaft;   a first cap, of which a lower portion thereof is fixed on an upper portion of the cylinder head, and including a first semicircular portion sliding with an exterior circumference of the camshaft formed at one side of a lower part thereof, and a second semicircular portion sliding with an exterior circumference of the control shaft formed at the other side of an upper part thereof; and   a second cap, of which a lower side thereof is fixed to an upper side of the first cap, and including a third semicircular portion corresponding to the second semicircular portion formed at one side of a lower part thereof, wherein a guide slot through which the drum shaft penetrates is formed at a center portion thereof.   
     
     
         2 . The engine of  claim 1 , further comprising:
 an input link connecting one end of the swing arm to the input cam eccentrically so as to rotate the swing arm on the drum shaft by the input cam;   an output link connecting the other end of the swing arm to the output cam so as to rotate the output link on the camshaft; and   a control link eccentrically connecting the control cam of the control shaft with the drum shaft so as to vary a position of the drum shaft disposed in the guide slot.   
     
     
         3 . The engine of  claim 2 , further comprising a guide drum that is fixed on the drum shaft and moves along the guide slot. 
     
     
         4 . The engine of  claim 2 , wherein a straight line connecting a rotation center of the drum shaft and a rotation center of the control shaft has an ascent angle ranging from approximately 10 to approximately 30 degrees in a central direction of the cylinder head. 
     
     
         5 . The engine of  claim 4 , wherein the camshaft is disposed at a predetermined distance from the drum shaft in a lower direction of the drum shaft. 
     
     
         6 . The engine of  claim 2 , wherein a first oil passage is formed along a central line of the control shaft, a second oil passage is diverged from the first oil passage and is formed along the control cam, the control link, and the drum shaft, and a third oil passage is formed along a central line of the drum shaft to lubricate sliding surface between the drum shaft and the swing arm.