Variable valve gear and method of controlling same

Abstract

A variable valve gear and a method of controlling the variable valve gear, 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 intake valve, to thereby stabilize operation of the solenoid on / off valve. A variable valve gear comprises: a hydraulic actuator provided with a valve gear mechanism for moving an air intake valve to open or close an air intake opening and also with a piston rod section for preventing the air intake valve from moving; a hydraulic control valve for controlling hydraulic oil supplied to or discharged from the hydraulic actuator, the hydraulic control valve having a valve member and a slide surface on which the valve member slides, the valve member being configured so as to move between a prevented position at which the piston rod section of the hydraulic actuator is prevented from operating and a released position at which the piston rod section is not prevented from operating; and a means for performing control valve stabilizing control for sliding the valve member of the hydraulic control valve when the air intake valve is being totally closed by the air intake valve, and the means also performing variable valve control for sliding, after the control valve stabilizing control is performed and while the air intake valve is being engaged in closing movement, the valve member to the prevented side to prevent the piston rod section from operating, stopping the closing movement of the air intake valve to thereby change the timing at which the air intake opening is totally closed.

Description

technical field [0001] The present invention relates to a variable valve device and a control method thereof. Background technique [0002] Conventionally, it is known that an engine mounted on a vehicle is equipped with a variable valve device that controls the opening and closing timing of the intake valve or the exhaust valve according to the operating state of the engine, and adjusts the amount of intake air or exhaust air. quantity. [0003] In this variable valve device, an electric motor or hydraulic pressure is used as a driving source, and a hydraulic drive type variable valve device driven by hydraulic pressure controls the flow of hydraulic oil to operate the variable valve. [0004] For example, a variable valve arrangement is provided which utilizes a directional control valve to prevent fluid from flowing out of a fluid actuator following a rocker arm at a prescribed timing, whereby the fluid actuator stops acting on The rocker arm maintains the open state of...

AI Technical Summary

Problems solved by technology

[0008] However, if the electromagnetic on-off valve disclosed in Patent Document 1 is maintained in the closed state, the oil film on the spool portion of the electromagnetic on-off valve is used up, and the operation may become unstable at the initial movement.

[0009] That is, after maintaining the closed state of the electromagnetic on-off valve, if the oil film of the spool valve portion is used up during the initial on-off operation of the electromagnetic on-off valve, the spool valve of the spool valve portion cannot operate smoothly. , especially during the cut-off action, the return of the slide valve is delayed (slowly), so that the timing of the full closing of the intake valve is greatly deviated. As a result, the compression ratio changes, which may lead to incomplete combustion

[0010] In addition, if the return of the slide valve is slow (delayed) so that the timing of the full closing of the intake valve is delayed, the intake valve may collide with the engine piston.

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