The present invention concerns a method and a device for electrically controlling a valve actuator in a two-stroke or four-stroke combustion engine where the actuator comprises a solenoid (A), a plunger (5) and a spring (6), wherein the engine has at least one cylinder (1) with at least one freely controllable engine valve disc (10) with corresponding valve stem (11) and a valve spring (4), where a distance (7) is provided between the lower end of the plunger and the upper end of the valve stem and where air is supplied, or exhaust gases are evacuated from, a combustion chamber (3) past a lower part of the valve stem with the valve disc via at least one channel (2) in the cylinder, wherein the valve actuator is activatable to open the engine valve. The invention is characterized in that the opening of the engine valve is initiated after activation of the solenoid, wherein the following acceleration of the plunger brings its lower end to strike the upper end of the valve stem for initial opening of the valve.

The present invention concerns a method and a device for electrically controlling a valve actuator in a two-stroke or four-stroke combustion engine where the actuator comprises a solenoid (A), a plunger (5) and a spring (6), wherein the engine has at least one cylinder (1) with at least one freely controllable engine valve disc (10) with corresponding valve stem (11) and a valve spring (4), where a distance (7) is provided between the lower end of the plunger and the upper end of the valve stem and where air is supplied, or exhaust gases are evacuated from, a combustion chamber (3) past a lower part of the valve stem with the valve disc via at least one channel (2) in the cylinder, wherein the valve actuator is activatable to open the engine valve. The invention is characterized in that the opening of the engine valve is initiated after activation of the solenoid, wherein the following acceleration of the plunger brings its lower end to strike the upper end of the valve stem for initial opening of the valve.

An actuator and a method for controlling such an actuator suitable for operating at least one gas exchange valve arranged in a cylinder head of an internal combustion engine. The actuator includes: an actuator piston disc, a cylinder volume adapted for the actuator piston disc, where the actuator piston disc divides the cylinder volume in a first portion and a second portion, an inlet channel arranged between a pressure fluid inlet and the first portion of the cylinder volume, a controllable first inlet valve arranged in the inlet channel, a controllable second inlet valve arranged downstream the controllable first inlet valve, an outlet channel arranged between the first portion of the cylinder volume and a pressure fluid outlet, and a controllable outlet valve arranged in the outlet channel.

An actuator for axial displacement of an object, includes an actuator piston and an actuator piston rod, wherein the piston is displaceable in the axial direction, and a hydraulic circuit including a liquid filled chamber, a first end of the actuator piston rod being displaceable in the axial direction within the liquid filled chamber, wherein an axially extending recess mouth in the liquid filled chamber is arranged to receive the first end. The actuator piston rod in the area of the first end presents a cylindrical envelope surface, and the recess presents a cylindrical inner surface having a matching shape, wherein the actuator includes a passage extending between the recess and liquid filled chamber when the cylindrical envelope surface and the cylindrical inner surface are located in overlapping configuration, wherein the passage presents at a braking overlap section a cross section area that decreases as a function of increasing overlap.