Variable valve device and method of controlling the same

Abstract

A variable valve device and a method of controlling the variable valve device, wherein, in order to prevent a shortage of oil film in a spool section, only the spool of a solenoid on/off valve is moved at a timing not affecting operation of an air intake valve, to thereby stabilize operation of the solenoid on/off valve.

1 . A variable valve device comprising:
 a valve actuation mechanism for moving an air intake valve of an engine to open or close an air intake port;   a hydraulic actuator provided with a piston rod section for preventing the air intake valve from moving;   a hydraulic control valve for controlling an operating oil supplied to or discharged from the hydraulic actuator, the hydraulic control valve having a spool and a slide surface on which the spool slides, the spool being configured so as to move between a prevented position at which the moving of the piston rod section of the hydraulic actuator is prevented and a released position at which the moving of the piston rod section is not prevented;   valve stabilizing control means for performing a control valve stabilizing control for sliding the spool of the hydraulic control valve during a period where the valve actuation mechanism causes the air intake valve to fully close the air intake port; and   variable valve control means for performing a variable valve control for sliding, while the air intake valve is being engaged in closing movement, the spool to the prevented side to prevent the moving of the piston rod section, stopping the closing movement of the air intake valve to thereby change a timing at which the air intake port is fully closed.   
     
     
         2 . The variable valve device according to  claim 1 , wherein the valve stabilizing control means sets a period of time during which the spool is kept on the prevented side in accordance with a rotation speed of the engine so that the period of time becomes longer as the rotation speed of the engine becomes lower. 
     
     
         3 . The variable valve device according to  claim 1 , wherein the valve stabilizing control means sequentially performs the control valve stabilizing control for cylinders of the engine in an order corresponding to a firing order of the cylinders. 
     
     
         4 . The variable valve device according to  claim 1 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means allows the valve stabilizing control means to perform the control valve stabilizing control during a period where the variable valve control is not performed.   
     
     
         5 . The variable valve device according to  claim 1 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means, in performing the variable valve control, allows the variable valve control means to perform the variable valve control after the valve stabilizing control means performs the control valve stabilizing control.   
     
     
         6 . A method of controlling a variable valve device, wherein
 an air intake valve of an engine is moved by the valve actuation mechanism to open or close an air intake port;   the moving of the air intake valve is prevented by a piston rod section of a hydraulic actuator;   a valve member of the hydraulic control valve for controlling an operation oil to be supplied to or discharged from the hydraulic actuator is caused to move between a prevented position at which the moving of the piston rod section of the hydraulic actuator is prevented and a released position at which the moving of the piston rod section is not prevented, so as to control an operation of the piston rod section of the hydraulic actuator, to thereby change a timing at which the air intake port is fully closed,   the method comprising:   performing a control valve stabilizing control for sliding the spool of the hydraulic control valve between the released position and the prevented position during a period where the valve actuation mechanism causes the air intake valve to fully close the air intake port; and   performing a variable valve control for sliding, while the air intake valve is being engaged in closing movement, the spool of the hydraulic control valve to the prevented side to prevent the moving of the piston rod section of the piston, stopping the closing movement of the air intake valve, to thereby change a timing at which the air intake port is fully closed.   
     
     
         7 . The method of controlling a variable valve device according to  claim 6 , wherein the control valve stabilizing control sets a period of time during which the spool is kept on the prevented side in accordance with a rotation speed of the engine so that the period of time becomes longer as the rotation speed of the engine becomes lower. 
     
     
         8 . The method of controlling a variable valve device according to  claim 6 , wherein the control valve stabilizing control is sequentially performed for cylinders of the engine in an order corresponding to a firing order of the cylinders. 
     
     
         9 . The method of controlling a variable valve device according to  claim 6 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   the control valve stabilizing control is performed during a period where the variable valve control is not performed.   
     
     
         10 . The method of controlling a variable valve device according to  claim 6 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   in performing the variable valve control, the variable valve control is performed after the control valve stabilizing control is performed.   
     
     
         11 . The variable valve device according to  claim 2 , wherein the valve stabilizing control means sequentially performs the control valve stabilizing control for cylinders of the engine in an order corresponding to a firing order of the cylinders. 
     
     
         12 . The variable valve device according to  claim 2 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means allows the valve stabilizing control means to perform the control valve stabilizing control during a period where the variable valve control is not performed.   
     
     
         13 . The variable valve device according to  claim 2 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means, in performing the variable valve control, allows the variable valve control means to perform the variable valve control after the valve stabilizing control means performs the control valve stabilizing control.   
     
     
         14 . The variable valve device according to  claim 3 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means allows the valve stabilizing control means to perform the control valve stabilizing control during a period where the variable valve control is not performed.   
     
     
         15 . The variable valve device according to  claim 3 , wherein
 the variable valve device further comprises control means for performing the variable valve control and the control valve stabilizing control in combination, and   the control means, in performing the variable valve control, allows the variable valve control means to perform the variable valve control after the valve stabilizing control means performs the control valve stabilizing control.   
     
     
         16 . The method of controlling a variable valve device according to  claim 7 , wherein the control valve stabilizing control is sequentially performed for cylinders of the engine in an order corresponding to a firing order of the cylinders. 
     
     
         17 . The method of controlling a variable valve device according to  claim 7 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   the control valve stabilizing control is performed during a period where the variable valve control is not performed.   
     
     
         18 . The method of controlling a variable valve device according to  claim 7 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   in performing the variable valve control, the variable valve control is performed after the control valve stabilizing control is performed.   
     
     
         19 . The method of controlling a variable valve device according  claim 8 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   the control valve stabilizing control is performed during a period where the variable valve control is not performed.   
     
     
         20 . The method of controlling a variable valve device according to  claim 8 , wherein
 the variable valve control and the control valve stabilizing control are performed in combination, and   in performing the variable valve control, the variable valve control is performed after the control valve stabilizing control is performed.