An actuating system of an engine valve comprises a movable member, for example, in the form of a master piston controlled by a cam of a camshaft. A slave piston is hydraulically controlled by the master piston by means of a volume of pressurized fluid, to open said engine valve against the action of a return spring. The system also comprises an auxiliary device for applying an additional force to the engine valve to keep the engine valve in a closed position. The auxiliary device is configured or controlled in such a way that the total force tending to keep the engine valve in its closed position varies during each rotation cycle of the cam. The total force is higher at least in one part of the rotation cycle of the cam wherein the engine valve must remain in its closed position, and is, instead, reduced at least in one part of the rotation cycle of the cam wherein the engine valve is not in its closed position.

Provided is a four stroke internal combustion engine comprising at least one cylinder arrangement, a crankshaft, a camshaft, and a turbine. The camshaft is synchronized with the crankshaft to rotate at a same rotational speed as the crankshaft. A linkage arrangement is configured to prevent the motion of the valve head every alternate rotation of the camshaft, such that the exhaust opening remains closed during a compression stroke of the piston. Also a method for controlling a four stroke internal combustion engine is disclosed.

A multicylinder internal combustion free-piston engine (FPE) with synchronized reciprocating plungers. The invention provides a solution for the problem of the slow engine speed typical of FPE's with heavy plunger mass. Bounce chambers fitted with sleeve valves control the engine's speed and stroke length. The invention's configuration prevents piston head-strikes and operates at standard compression ratios. Piston pop-top intake valves allow uniflow scavenging and connecting rod oil channels provide lubrication with no combustion chamber contamination. Poppet combustion head valves are operated by linear cams attached to the plungers. Hydraulic valve actuators implement variable valve timing under computer control.

The invention relates to an internal combustion engine gas exchange valve actuator and is used to displace one or more internal combustion engine valves thereby improving the operation and extending the capabilities of the engine. The actuator includes a casing (2) attached to the engine head (1) and with a hollow cylinder (3) formed inside it and containing a reciprocating piston (6) with a piston rod. Provision is made in the casing (2) which is closed by a cap (4), for a loop for controlled charging and discharging of the pressurized fluid and for a solenoid valve with direct electromagnetic control. The solenoid valve is positioned above the piston (6) and is formed as a plunger (19) having a lower cylindrical widening with axial orifices (20) and an upper part with a central recess (22) and radial orifices (23) and (24).

A hydraulic valve brake for a hydraulic valve drive of an internal combustion engine is provided. The valve brake includes a housing with a housing wall and with a housing base, and includes a piston which moves axially in the housing and one end side of which, together with the housing wall and the housing base, delimits a hydraulic pressure chamber and the other end side of which actuates a gas exchange valve. The housing wall is perforated in the region of the pressure chamber by one or more overflow openings, the opening cross sections of which are controlled by a control edge, which delimits the end side at the pressure chamber side, of the piston. In this case, it is the intention for the axial distance (h) between the control edge of the piston, when the latter is fully retracted into the housing, and the housing base to be set by a spacer of predetermined thickness (d).

A engine control device includes an variable exhaust valve mechanism 72 which varies an opening and closing timing of an exhaust valve 22, and a PCM 10 which controls the variable exhaust valve mechanism 72 such that the opening and closing timing of the exhaust valve 22 is varied, wherein the variable exhaust valve mechanism 72 is configured such that a lift amount of the exhaust valve 22 becomes smaller as a retarded degree of the valve opening timing increases, and the PCM 10 is configured to set a maximum retarded valve opening timing in an exhaust stroke based on the lift amount at an exhaust top dead center, and to control the variable exhaust valve mechanism 72 so as to open the exhaust valve 22 in advance of the maximum retarded valve opening timing.

A hydraulic fluid system for a variable valve train system is provided that allows hydraulic fluid flow from a high pressure chamber to a medium pressure chamber during a higher pressure phase after a control valve closes. The hydraulic fluid system includes a housing defining (a) the middle pressure chamber which is connected to a hydraulic fluid supply, and (b) the high pressure chamber which contains hydraulic fluid that is pressurized by a pump piston assembly configured to engage a rotating cam. A control valve selectively provides a first flowpath for hydraulic fluid between the middle pressure chamber and the high pressure chamber. A bypass valve selectively provides a second flowpath for hydraulic fluid between the middle pressure chamber and the high pressure chamber based on a pressure of the hydraulic fluid in the high pressure chamber.

A thrust reverser assembly for a turbine engine can include a core engine surrounded by a nacelle. A bypass duct can be formed in the space between the core engine and the nacelle. A blocker door can be movable to a deployed position extending into the bypass duct. A stop can be provided on the core engine to abut and support force applied to the deployed blocker door. The stop can have an airfoil shape.

In an engine comprising a cylinder having first and second engine valves of a same function type, a system for actuating the first and second engine valves comprises a first and second master pistons that receive first and second valve actuation motions from respective ones of a first and second valve actuation motion source, a first slave piston operatively connected to the first engine valve and configured to hydraulically receive the first valve actuation motions from at least the first master piston and a second slave piston operatively connected to the second engine valve and configured to hydraulically receive the second valve actuation motions from the second master piston. The system further comprises an accumulator and a mode selector valve in hydraulic communication with the first master piston, the first slave piston and the accumulator. The mode selector valve may selectively hydraulically connect the first master piston to the accumulator.

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.