Valve Mechanism for Internal Combustion Engine

Abstract

Disclosed is a valve mechanism for an internal combustion engine that uses a motor to open/close a valve body of each cylinder. The valve mechanism includes a camshaft that is rotated by the motor and equipped with cams for driving the valve body of a plurality of cylinders; control means that drives the motor while making a mode switch between a normal rotation drive mode in which the camshaft is continuously rotated in one direction to drive the valve body and a swing drive mode in which the camshaft is swung to drive the valve body; and change means that changes the relative angular positions of cylinder-specific cams on the camshaft.

1 . A valve mechanism for an internal combustion engine that uses a motor to drive for opening/closing a valve body of each cylinder, the valve mechanism comprising:
 a camshaft that is rotated by the motor and equipped with a plurality of same sort of cams which are provided to either intake side or exhaust side for driving same sort of valve bodies of a plurality of cylinders; and   cam angle change means for changing the relative angle between the plurality of same sort of cams that are driven by the same motor.   
   
   
       2 . The valve mechanism according to  claim 1 , further comprising:
 control means that drives the motor while making a mode switch between a normal rotation drive mode in which the camshaft is continuously rotated in one direction to drive the same sort of valve bodies and a swing drive mode in which the camshaft is swung to drive the same sort of valve bodies,   wherein the cam angle change means changes the relative angular positions of the same sort of cams when a mode switch is made.   
   
   
       3 . The valve mechanism according to  claim 2 ,
 wherein the camshaft has the same sort of cams for driving the same sort of valve bodies of two cylinders and is formed by combining a first camshaft, which has a same sort of cam for one cylinder, and a second camshaft, which has a same sort of cam for the other cylinder; and   wherein the cam angle change means changes the relative angular positions of the same sort of cam on the first camshaft and the same sort of cam on the second camshaft by changing the relative angular positions of the first camshaft and the second camshaft.   
   
   
       4 . The valve mechanism according to  claim 3 , further comprising:
 angle lock means that is provided at a junction between the first camshaft and the second camshaft to lock the relative angular positions of the first camshaft and the second camshaft in the normal rotation drive mode and in the swing drive mode, respectively.   
   
   
       5 . The valve mechanism according to  claim 4 ,
 wherein the angle lock means includes a lock pin, which is provided for one of the first camshaft and the second camshaft, and a first engagement hole and a second engagement hole, which are made in the other of the first camshaft and the second camshaft to engage with the lock pin;   wherein, in the normal rotation drive mode, the lock pin engages with the first engagement hole to lock the relative angular positions of the first camshaft and the second camshaft; and   wherein, in the swing drive mode, the lock pin engages with the second engagement hole to lock the relative angular positions of the first camshaft and the second camshaft.   
   
   
       6 . The valve mechanism according to  claim 5 , further comprising:
 lock pin disengagement means that supplies oil to the first or second engagement hole to disengage the lock pin from the first or second engagement hole,   wherein the lock pin disengagement means includes an oil path that communicates with either the first engagement hole or the second engagement hole in accordance with the relative angular positions of the first camshaft and the second camshaft;   wherein, in the normal rotation drive mode, the oil path communicates with only the first engagement hole, and when a mode switch is to be made to the swing drive mode, oil is supplied to the oil path to disengage the lock pin from the first engagement hole; and   wherein, in the swing drive mode, the oil path communicates with only the second engagement hole, and when a mode switch is to be made to the normal rotation drive mode, oil is supplied to the oil path to disengage the lock pin from the second engagement hole.   
   
   
       7 . The valve mechanism according to  claim 2 , wherein the same sort of valve body is an intake valve, and when a mode switch is made from the normal rotation drive mode to the swing drive mode, the valve opening timing of the same sort of valve body retards. 
   
   
       8 . The valve mechanism according to  claim 2 , wherein the same sort of valve body is an exhaust valve, and when a mode switch is made from the normal rotation drive mode to the swing drive mode, the valve opening timing of the same sort of valve body advances. 
   
   
       9 . The valve mechanism according to  claim 2 , further comprising:
 a hydraulic lash adjuster for adjusting the clearance between the same sort of valve body and the same sort of cam.   
   
   
       10 . The valve mechanism according to  claim 9 , further comprising:
 a rocker arm for transmitting the acting force of the same sort of cam to the same sort of valve body.   
   
   
       11 . The valve mechanism according to  claim 2 , wherein the motor is positioned at a longitudinal end of the camshaft. 
   
   
       12 . The valve mechanism according to  claim 2 , wherein the motor is positioned above the camshaft. 
   
   
       13 . The valve mechanism according to  claim 1 ,
 wherein the internal combustion engine performs a fuel cut-off operation at the time of vehicle deceleration; and   wherein, when the fuel cut-off operation is performed, the cam angle change means changes the relative angular positions of the same sort of cams so as to close the same sort of valve bodies of all cylinders.   
   
   
       14 . The valve mechanism according to  claim 13 ,
 wherein the camshaft includes an intake valve camshaft for driving intake valves and an exhaust valve camshaft for driving exhaust valves; and   wherein, when the fuel cut-off operation is performed, the cam angle change means changes the relative angular positions of the same sort of cams on at least either the intake valve camshaft or the exhaust valve camshaft so as to close the same sort of valve bodies of all cylinders.   
   
   
       15 . The valve mechanism according to  claim 14 , wherein, when the fuel cut-off operation is performed, the cam angle change means changes the relative angular positions of the same sort of cams on one of the intake valve camshaft and the exhaust valve camshaft so as to close the same sort of valve bodies of all cylinders and changes the relative angular positions of the same sort of cams on the other of the intake valve camshaft and the exhaust valve camshaft so as to open only the same sort of valve bodies of some of the all cylinders. 
   
   
       16 . The valve mechanism according to  claim 15 , wherein, when the fuel cut-off operation is performed, the cam angle change means changes the relative angular positions of the same sort of cams on the exhaust valve camshaft so as to close the same sort of valve bodies of all cylinders and changes the relative angular positions of the same sort of cams on the intake valve camshaft so as to open only the same sort of valve bodies of some of the all cylinders. 
   
   
       17 . The valve mechanism according to  claim 15 , wherein the some of the all cylinders are two cylinders in which pistons move in opposite directions. 
   
   
       18 . The valve mechanism according to  claim 15 , wherein the some of the all cylinders are two cylinders that are 180 crank angle degrees out of phase with each other. 
   
   
       19 . The valve mechanism according to  claim 17 , wherein the cam angle change means changes the relative angular positions of the same sort of cams so that the two cylinders open the same sort of valve bodies by the same amount. 
   
   
       20 . The valve mechanism according to  claim 15 , wherein the cam angle change means changes the opening amount of the same sort of valve body in accordance with a requested vehicle speed level of a vehicle in which the internal combustion engine is mounted. 
   
   
       21 . A valve mechanism for an internal combustion engine that uses a motor to drive for opening/closing a valve body of each cylinder, the valve mechanism comprising:
 a camshaft that is rotated by the motor and equipped with a plurality of same sort of cams which are provided to either intake side or exhaust side for driving same sort of valve bodies of two cylinders, and formed by combining a first camshaft, which has a same sort of cam for one cylinder, and a second camshaft, which has a same sort of cam for the other cylinder; and   cam angle change means, which changes the relative angular positions of the same sort of cam on the first camshaft and the same sort of cam on the second camshaft by changing the relative angular positions of the first camshaft and the second camshaft.   
   
   
       22 . The valve mechanism according to  claim 21 , further comprising:
 control means that drives the motor while making a mode switch between a normal rotation drive mode in which the camshaft is continuously rotated in one direction to drive the same sort of valve bodies and a swing drive mode in which the camshaft is swung to drive the same sort of valve bodies,   wherein the cam angle change means changes the relative angular positions of the same sort of cams when a mode switch is made.   
   
   
       23 . The valve mechanism according to  claim 22 , further comprising:
 angle lock means that is provided at a junction between the first camshaft and the second camshaft to lock the relative angular positions of the first camshaft and the second camshaft in the normal rotation drive mode and in the swing drive mode, respectively.   
   
   
       24 . The valve mechanism according to  claim 23 ,
 wherein the angle lock means includes a lock pin, which is provided for one of the first camshaft and the second camshaft, and a first engagement hole and a second engagement hole, which are made in the other of the first camshaft and the second camshaft to engage with the lock pin;   wherein, in the normal rotation drive mode, the lock pin engages with the first engagement hole to lock the relative angular positions of the first camshaft and the second camshaft; and   wherein, in the swing drive mode, the lock pin engages with the second engagement hole to lock the relative angular positions of the first camshaft and the second camshaft.   
   
   
       25 . The valve mechanism according to  claim 24 , further comprising:
 lock pin disengagement means that supplies oil to the first or second engagement hole to disengage the lock pin from the first or second engagement hole,   wherein the lock pin disengagement means includes an oil path that communicates with either the first engagement hole or the second engagement hole in accordance with the relative angular positions of the first camshaft and the second camshaft;   wherein, in the normal rotation drive mode, the oil path communicates with only the first engagement hole, and when a mode switch is to be made to the swing drive mode, oil is supplied to the oil path to disengage the lock pin from the first engagement hole; and   wherein, in the swing drive mode, the oil path communicates with only the second engagement hole, and when a mode switch is to be made to the normal rotation drive mode, oil is supplied to the oil path to disengage the lock pin from the second engagement hole.