A system for variable actuation of an engine valve of an engine includes a master piston driven by a cam of a camshaft. A slave piston is driven by the master piston by a volume of pressurized fluid. The slave piston causes the engine valve to open, against the action of a spring. A control valve controls a communication between pressurized fluid and an environment at lower pressure, with which a fluid accumulator is in communication. A control unit is programmed for controlling the control valve according to one or more different valve modes. When one of these valve modes is actuated, the control valve opens the communication in advance with respect to the end of the lift cycle of the cam, and not after closing of the engine valve to prevent or reduce a decrease in pressure in the volume of pressurized fluid after closing of the engine valve.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively, the camshaft inserted to the first and second cam portions of which relative phase angles with respect to the camshaft are variable; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a cam lifter in which the first and second inner brackets are rotatably inserted, and a cam lifter guide slantly formed on the cam lifter; a cam cap rotatably supporting the first and the second cam portions, and the cam lifter slidably mounted to the cam cap; a control portion including a screw shaft parallel to the camshaft; and an adapter engaged with the screw shaft, on which an adapter guide slidably engaged with the cam lifter guide and moving a relative position of the cam lifter.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively, the camshaft inserted to the first and second cam portions of which relative phase angles with respect to the camshaft are variable; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a cam lifter in which the first and second inner brackets are rotatably inserted, and a cam lifter guide slantly formed on the cam lifter; a cam cap rotatably supporting the first and the second cam portions, and the cam lifter slidably mounted to the cam cap; a control portion including a screw shaft parallel to the camshaft; and an adapter engaged with the screw shaft, on which an adapter guide slidably engaged with the cam lifter guide and moving a relative position of the cam lifter.

A continuous variable valve duration apparatus may include a camshaft, a first and second cam portions on which a cam is formed respectively, of which the camshaft is inserted thereto and of which relative phase angles with respect to the camshaft are variable, a first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively, a slider housing in which the first and second inner brackets are rotatably inserted, of which a relative position with respect to the camshaft is variable, and on which a control slot is formed, a cam cap rotatably supporting the first and the second cam portions and to which the slider housing is slidably mounted, a control shaft parallel to the camshaft and on which a control rod is eccentrically formed, an eccentric plate rotatably connected to the control rod and rotatably inserted into the control slot, a separation prevention pin disposed to inhibit the eccentric plate from being separated from the slider housing and a control portion selectively rotating the control shaft so as to controlling a position of the slider housing.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively, to which the camshaft is inserted and of which relative phase angles with respect to the camshaft are variable; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and second inner brackets are rotatably inserted, and on which a control slot is formed; a cam cap rotatably supporting the first and the second cam portions and to which the slider housing is slidably mounted; a control shaft which is parallel to the camshaft and on which a control rod is eccentrically formed; an eccentric plate rotatably connected to the control rod and rotatably inserted into the control slot; and a control portion selectively rotating the control shaft.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively, to which the camshaft is inserted and of which relative phase angles with respect to the camshaft are variable; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and second inner brackets are rotatably inserted, and on which a control slot is formed; a cam cap rotatably supporting the first and the second cam portions and to which the slider housing is slidably mounted; a control shaft which is parallel to the camshaft and on which a control rod is eccentrically formed; an eccentric plate rotatably connected to the control rod and rotatably inserted into the control slot; and a control portion selectively rotating the control shaft.

A transmission assembly for a mechanically controllable valve train. The transmission assembly includes a gas exchange valve, a coupling element, a slotted guide module comprising slotted guide tracks, mounting members, a camshaft, cam following roller elements, at least two transmission elements, and a valve stroke adjustment device. Each transmission element is directly or indirectly in an operative connection with one gas exchange valve via the coupling element. The transmission elements are mounted via the mounting members in the slotted guide tracks. Each transmission element is in an operative connection with the camshaft via the cam following roller elements. The valve stroke adjustment device sets different maximum strokes of a gas exchange valve. The mounting members and the cam following roller elements are mounted on a rotary axis. Each of the cam following roller elements has two mounting members assigned thereto to increase a rigidity of the rotary axis.

A transmission assembly for a mechanically controllable valve train. The transmission assembly includes a gas exchange valve, a coupling element, a slotted guide module comprising slotted guide tracks, mounting members, a camshaft, cam following roller elements, at least two transmission elements, and a valve stroke adjustment device. Each transmission element is directly or indirectly in an operative connection with one gas exchange valve via the coupling element. The transmission elements are mounted via the mounting members in the slotted guide tracks. Each transmission element is in an operative connection with the camshaft via the cam following roller elements. The valve stroke adjustment device sets different maximum strokes of a gas exchange valve. The mounting members and the cam following roller elements are mounted on a rotary axis. Each of the cam following roller elements has two mounting members assigned thereto to increase a rigidity of the rotary axis.

A camshaft includes a carrier shaft which can be mounted rotatably along a shaft axis and at least one cam pack disposed axially displaceably on the carrier shaft. The cam pack includes at least two cams and at least one adjusting member for axial adjustment of the cam pack. The cams and the at least one adjusting member are connected to one another in an axially adjacent configuration and can be mounted axially displaceably as a composite structure in a direct configuration on the carrier shaft. A method for producing a camshaft and a cam pack are also provided.

A camshaft includes a carrier shaft which can be mounted rotatably along a shaft axis and at least one cam pack disposed axially displaceably on the carrier shaft. The cam pack includes at least two cams and at least one adjusting member for axial adjustment of the cam pack. The cams and the at least one adjusting member are connected to one another in an axially adjacent configuration and can be mounted axially displaceably as a composite structure in a direct configuration on the carrier shaft. A method for producing a camshaft and a cam pack are also provided.