Engine of variable stroke type

Abstract

An engine of a variable stroke type may include a camshaft that a first cam and a second cam which may be adjacent to each other may be formed on the camshaft, a valve that may be disposed to be moved by the first cam or the second cam, and a tappet that may be engaged to the valve and disposed between the first and second cam and the valve to make the first cam move the valve or to make the second cam move the valve, wherein the second cam has a rotational phase difference with the first cam in a rotating direction of the camshaft.

What is claimed is: 
     
         1 . An engine of a variable stroke type, comprising:
 a camshaft that a first cam and a second cam which are adjacent to each other are formed on the camshaft;   a valve that is disposed to be moved by the first cam or the second cam; and   a tappet that is engaged to the valve and disposed between the first and second cam and the valve to make the first cam move the valve or to make the second cam move the valve;   wherein the second cam has a rotational phase difference with the first cam in a rotating direction of the camshaft.   
     
     
         2 . The engine of the variable stroke type of  claim 1 , wherein the number of the first cam is one in one rotational area of the camshaft, and the number of the second cam is two in one rotational area of the camshaft. 
     
     
         3 . The engine of the variable stroke type of  claim 2 , wherein two second cams have a phase difference of 180 degrees. 
     
     
         4 . The engine of the variable stroke type of  claim 3 , wherein the valve is an intake valve. 
     
     
         5 . The engine of the variable stroke type of  claim 3 , wherein the tappet includes:
 an inner tappet corresponding to the first cam;   an outer tappet corresponding to the second cam;   a middle tappet that is disposed between the inner tappet and the outer tappet to press the valve; and   a latching pin that is moved by a hydraulic pressure supplied to an end thereof to latch the middle tappet with the outer tappet or to latch the middle tappet with the inner tappet.   
     
     
         6 . The engine of the variable stroke type of  claim 5 , further comprising:
 a first lost spring that elastically biases the inner tappet toward the camshaft from the middle tappet; and   a second lost spring that elastically biases the outer tappet toward the camshaft from the middle tappet.   
     
     
         7 . The engine of the variable stroke type of  claim 5 , further comprising a latching spring that is disposed inside the middle tappet to elastically bias the latching pin toward the outer tappet in such a way that the middle tappet is selectively latched with the outer tappet. 
     
     
         8 . The engine of the variable stroke type of  claim 7 , wherein the hydraulic pressure is supplied to the end of the latching pin in such a way that the latching pin is pushed from a side of the outer tappet to a side of the middle tappet. 
     
     
         9 . The engine of the variable stroke type of  claim 1 , wherein the number of the first cam is one in one rotational area of the camshaft and the number of the second cam is one in one rotational area of the camshaft. 
     
     
         10 . The engine of the variable stroke type of  claim 9 , wherein the first cam has a phase difference of 180 degrees with the second cam. 
     
     
         11 . The engine of the variable stroke type of  claim 9 , wherein the valve is an exhaust valve. 
     
     
         12 . The engine of the variable stroke type of  claim 9 , wherein the tappet includes:
 an inner tappet that is disposed to push the valve corresponding to the first cam;   an outer tappet corresponding to the second tappet; and   a latching pin that is operated by a hydraulic pressure supplied to an end of the latching pin so as to latch the inner tappet with the outer tappet.   
     
     
         13 . The engine of the variable stroke type of  claim 12 , further comprising a lost spring that elastically biases the outer tappet from the inner tappet toward the camshaft. 
     
     
         14 . The engine of the variable stroke type of  claim 12 , further comprising a latching spring that is disposed inside the outer tappet elastically biases the latching pin toward the inner tappet in such a way that the inner tappet is latched with the outer tappet. 
     
     
         15 . The engine of the variable stroke type of  claim 12 , wherein a hydraulic pressure is supplied to the end of the latching pin to push the latching pin from a side of the inner tappet to a side of the outer tappet.