A valve train device for an engine includes: a shaft portion; a cam element portion which is mounted on the shaft portion; and an operation member. The cam element portion includes a first end surface cam and a second end surface cam. Each of the first end surface cam and the second end surface cam includes a lift portion. The operation member includes a first operation member and a second operation member. The first operation member causes the cam element portion to move in a first direction, and the second operation member causes the cam element portion to move in a second direction. The first end surface cam includes a first slope portion, and guides the first operation member radially outwardly; and a displacement allowing portion which is formed adjacent to the first slope portion, and allows relative displacement between the first operation member, and the cam element portion.

A system for controlling valve opening/closing timing that allows an unlocking operation to be reliably performed is configured. When extracting a lock member from a recess, a second control valve is set to an unlock position, a first control valve is set to a predetermined position, and a relative rotation phase is displaced. As a result, the relative rotation phase is displaced in a direction opposite to the direction of displacement by cam average torque from a camshaft. Afterward, by setting the first control valve to a neutral position, the relative rotation phase is displaced by the cam average torque, and when this displacement occurs, a state in which the lock member is separated from an inner wall of the recess is created, thus facilitating extraction of the lock member from the recess.

A method is disclosed for adaptively controlling an engine system of a motor vehicle comprising the steps of evaluating the outputs from angular position sensors associated with inlet and exhaust camshafts of an engine of the engine system to establish whether differences between the currently measured positions and previously saved positions are the result of elongation of an endless drive used to drive the camshafts or due to some other reason. If it is confirmed that the differences are due to elongation of the endless drive then the measured values of angular position are used in the control of a number of engine functions.

A valve train device for an engine includes: a shaft portion; a cam element portion which is mounted on the shaft portion; and an operation member. The cam element portion includes a first end surface cam and a second end surface cam. Each of the first end surface cam and the second end surface cam includes a lift portion. The operation member includes a first operation member and a second operation member. The first operation member causes the cam element portion to move in a first direction, and the second operation member causes the cam element portion to move in a second direction. The first end surface cam includes a first slope portion, and guides the first operation member radially outwardly; and a displacement allowing portion which is formed adjacent to the first slope portion, and allows relative displacement between the first operation member, and the cam element portion.

A system for controlling valve opening/closing timing that allows an unlocking operation to be reliably performed is configured. When extracting a lock member from a recess, a second control valve is set to an unlock position, a first control valve is set to a predetermined position, and a relative rotation phase is displaced. As a result, the relative rotation phase is displaced in a direction opposite to the direction of displacement by cam average torque from a camshaft. Afterward, by setting the first control valve to a neutral position, the relative rotation phase is displaced by the cam average torque, and when this displacement occurs, a state in which the lock member is separated from an inner wall of the recess is created, thus facilitating extraction of the lock member from the recess.