Abstract: A variable valve device has a hydraulic actuator that implements discharge of operating oil in a pressure chamber and a hydraulic control valve that controls supply and discharge of the operating oil to and from the hydraulic actuator by opening and closing, thereby preventing the closing movement of the intake valve. After a signal that closes the hydraulic control valve in a current engine control cycle is output at a prescribed crank angle, the crank angle of a crankshaft, when surge pressure in the pressure chamber has exceeded a prescribed threshold value resulting from closing of the hydraulic control valve, is determined, and at least either an output crank angle or a waveform of the signal that closes the hydraulic control valve is corrected based on the operation start crank angle, and the corrected signal is output to the hydraulic control valve in a next control cycle.

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.

Abstract: An engine valve device includes an intake valve which opens and closes an intake port by a pressing force of a rotating cam and a pressing force of a valve spring, a piston which is movable in a same direction as the intake valve, a cylinder portion which houses the piston such that the piston is movable inside, a hydraulic actuator including the piston and the cylinder portion, a supply discharge pipe line which communicates with a pressure chamber formed by the piston and the cylinder portion, an accumulator which accumulates hydraulic oil flowed out from the pressure chamber via the supply discharge pipe line, and an electromagnetic on-off valve which controls a flow of the hydraulic oil between the pressure chamber and the accumulator. The electromagnetic on-off valve is arranged on the supply discharge pipe line between the hydraulic actuator and the accumulator.