Abstract: A valve actuator assembly for an engine includes a movable poppet valve, and movable first and second spool valves. The assembly also includes an intermediate channel interconnecting the first and second spool valve, a driving channel, and a first and second feedback channel interconnecting the second spool valve and the poppet valve. The valve actuator assembly includes an actuator cooperating with the first spool valve to position the first spool valve to selectively allow high pressure fluid flow to the second spool valve and the driving channel to position the engine valve. The valve actuator assembly further includes a first and second on/off valve in respective fluid communication with the first feedback channel and the second feedback channel to selectively exhaust the first and second feedback channel to control motion of the second spool valve. The second spool valve includes a detent feature operable to maintain the second spool valve in a center biased position.

Abstract: A control system is described that comprises a manifold, at least one valve device operable to control the delivery of fluid from the manifold, and a drive member located within the manifold and rotatable to control the operation of the at least one valve device.

Abstract: An internal-combustion engine provided with a simplified system for variable actuation of the valves, which envisages for two different engine cylinders a single solenoid valve that controls connection to an exhaust channel of two pressurized chambers associated to the intake valves of the two different cylinders.

Abstract: A method for operating a multi-cylinder internal combustion engine includes controlling opening of intake or exhaust valves, via a step of generating a control current in a control circuit for an electrical actuator coupled with the valve. The control circuit is then monitored for an induced current that differs from the control current, and a signal outputted that is indicative of valve performance responsive to monitoring the control circuit. Another operating method includes determining engine valve performance and also trimming an engine valve based on one signal which is indicative of valve performance. An internal combustion engine includes an electrical actuator configured to control opening or closing of one of an intake valve and an exhaust valve.

Abstract: A valve control for a gas exchange valve of an internal combustion engine includes at least one spring element for preloading the valve in an end position and a fixing device for the releasable fixing of the valve. The spring element in a moveable insert, which by means of an actuation device is adjustable in actuation direction of the valve between an end position close to the valve disc and an end position far from the valve disc for adjusting a preload applied on the valve by the spring element.

Abstract: A valve drive (1) of an internal combustion engine which is used to actuate a gas exchange valve (6) is provided. Displacement of the valve takes place when a cam (9) is lifted and when a hydraulic force applying device (12) is lifted. A piston (13) of the force applying device can be displaced from a first end position (A) to a second end position by feeding a hydraulic medium, which can be pressure-adjusted, from a hydraulic medium line (24) into a pressure chamber (21). The pressure chamber (21) can be connected to the hydraulic medium line (24) via a shut-off element (20) which is open towards the pressure chamber (21) and which is arranged in the housing (15) and also by means of at least one passage (26) in the housing (15). The passage (26) is at least partially blocked by an external casing surface (16) of the piston (13) in the first end position (A) thereof.

Abstract: A valve actuation system for providing added motion in the valve mechanism of an internal combustion engine with at least one inlet valve and at least one exhaust valve is provided. The valve mechanism includes a rotatable camshaft including rising and falling ramps designed to interact with a valve control plunger inside a cylinder for actuation of the inlet or exhaust valve under the action of a valve spring. The cylinder communicates with a hydraulic fluid feed line via a check valve and with a hydraulic control circuit allowing a return movement of a valve to be delayed in relation to the timing of the corresponding falling ramp. The hydraulic control circuit includes a first and a second hydraulic fluid flow restrictor connected to the control plunger cylinder at different levels along its longitudinal axis. A selector valve enables a connection between the cylinder and hydraulic fluid return line to be opened via either one only or both flow restrictors.

Abstract: A valve actuation system for providing added motion in the valve mechanism of an internal combustion engine with at least one inlet valve and at least one exhaust valve is provided. The valve mechanism includes a rotatable camshaft including rising and falling ramps designed to interact with a valve control plunger inside a cylinder for actuation of the inlet or exhaust valve under the action of a valve spring. The cylinder communicates with a hydraulic fluid feed line via a check valve and with a hydraulic control circuit allowing a return movement of a valve to be delayed in relation to the timing of the corresponding falling ramp. The hydraulic control circuit includes a first and a second hydraulic fluid flow restrictor connected to the control plunger cylinder at different levels along its longitudinal axis. A selector valve enables a connection between the cylinder and hydraulic fluid return line to be opened via either one only or both flow restrictors.

Abstract: To provide a variable valve driving device which can accurately control the lift amount of valves and can be manufactured at a low cost. The device has: valves (10) serving as intake valves or exhaust valves of an engine; springs (11) for biasing the valves (10) in the valve closing direction; a cam (12) for pressing the valves (10) in the valve opening direction against a biasing force of the springs; a piston (19) joined to the valves (10); a control chamber (21) configured by a piston insertion hole (20) into which the piston (19) is inserted; and a control mechanism (24) for changing the valve closing timing of the valves (10) by controlling the introduction and discharge of a working fluid into and from the control chamber (21).

Abstract: A valve actuation system for an engine is provided. The valve actuation system can include two or more engine cylinders, each cylinder having at least one intake valve configured to control air-flow into each of the two or more cylinders and at least one exhaust valve configured to control the flow of exhaust gases out of each of the two or more cylinders. The at least one first cylinder includes an exhaust cam lobe configured to control the valve timing of an exhaust valve of the at least one first cylinder and to cause an exhaust valve of a second cylinder to open during an expansion stroke of the second cylinder.

Abstract: A cylinder head cover covers a cylinder head of an internal combustion engine. The engine has a variable valve actuation mechanism and a control valve for controlling supply and drainage of hydraulic oil to and from the variable valve actuation mechanism. The cylinder head cover includes a cover main body fixed to the cylinder head and a valve case to which the control valve is attached. The valve case is caused to contact a side of the cover main body that corresponds to the cylinder head. Therefore, the cylinder head cover maintains a firm attachment of the valve case to the cylinder head.

Abstract: Actuators, and corresponding methods and systems for controlling such actuators, provide independent lift and timing control with minimum energy consumption. In an exemplary embodiment, an electromechanical actuator comprises a housing, first and second electromagnets rigidly disposed in the housing and separated from each other by an armature chamber, an armature disposed in the armature chamber and movable between the first and second electromagnets, an armature rod rigidly connected with the armature and operably connected with a load, at least one first actuation spring biasing the armature in a first direction, at least one second actuation spring biasing the armature in a second direction, and one fluid-operated spring controller capable of controlling the position of the first-direction end of the at least one second actuation spring. The spring controller allows the actuation springs at their least compressed state and the engine valve closed when engine power is off.

Abstract: According to some embodiments, there is provided a four-stroke cycle internal combustion engine in which an amount of valve lift is switchable in more multiple steps according to an operating range. In a four-stroke cycle internal combustion engine 1 including an intake valve 7, an exhaust valve 6, and a valve driving device 8 open/close-driving the intake valve 7 and the exhaust valve 6, at least one of the intake valve 7 and the exhaust valve 6 is provided in plurality, and the valve driving device 8 includes a first and a second variable valve system 26, 26? performing multi-step switching control of at least one of an opening/closing timing and an amount of lift of the valve provided in plurality, independently on a per valve basis.

Abstract: A device for the operation of a valve (5) to the combustion chamber (6) of a combustion engine, wherein the combustion engine comprises a cylinder, a piston (3) displacably arranged in the cylinder (2), and a combustion chamber (6) delimited by the cylinder (2) and the piston (3), and said valve (5), and wherein the device comprises a valve actuator (7) that comprises an actuator chamber (8), an actuator piston (9) displacably arranged in the latter and arranged to drive the valve (5), and a communication channel (11) through which a pressure fluid is conducted into the combustion chamber (8) for the driving of the actuator piston (9) and, thereby, the valve (5) in a direction in which the valve (5) is opened. The communication channel (11) extends from the combustion chamber (6) to the actuator chamber (8), and said pressure fluid comprises fluid pressurized by the pressure in the combustion chamber (6).

Abstract: Hydraulic spring drive apparatus comprising: a rotatable cam shaft having fixed thereon a number of cams; a number of rocker arms, one following each cam, each pivotally attached at one end to a pressure bar and at another to an expansible, compressible connecting means in turn connected to a crank portion of a crank shaft. The cams, crank shaft, and expansible compressible connecting means are arranged so that a number of connecting means expand against the compression of one connecting means. The pressure bar is movable to position the rocker arms for a selected degree of connecting means compression.

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.

Abstract: Systems and methods of actuating engine valves using a hydraulic valve actuation system are disclosed. The valve actuation system includes a master piston and two slave pistons slidably disposed in bores provided in a housing. The master piston and two slave pistons are connected together by a hydraulic circuit. Linear motion imparted to the master piston is transferred to the two slave pistons via the hydraulic circuit. In turn, the two slave pistons may actuate one or more engine valves directly or through an intermediate valve bridge. A valve seating device may be provided to assist in seating the engine valves in embodiments where the valve actuation system is adapted to provide variable valve actuation.

Abstract: Systems and methods for hydraulic and/or variable valve actuation of engine valves are disclosed. An embodiment of the present invention may include a hydraulic valve actuation system operatively connected to an engine valve. First and second control valves may be operatively connected to the hydraulic valve actuation system and adapted to selectively release hydraulic fluid from the hydraulic valve actuation system independent of one another. The first control valve is preferably a solenoid actuated trigger valve and the second control valve is preferably a mechanically or hydraulically actuated valve.

Abstract: A hydraulic circuit in fluid communication with an added motion valve system is disclosed. The hydraulic circuit in fluid communication with an added motion valve system includes at least a first valve that permits flow of a fluid in a first fluid supply channel to an added motion actuator volume by way of a first fluid port and a second fluid port and at least a second valve that permits flow of the fluid in a second fluid supply channel to the first fluid port, the second fluid port, and a third fluid port. A method for controlling a hydraulic circuit in fluid communication with an added motion valve system is also disclosed.

Abstract: The present invention relates to a method of controlling an internal-combustion engine comprising at least one cylinder (10) with at least one burnt gas exhaust means (12) including an exhaust valve (16) whose opening/closing is controlled by control means (22) and an exhaust pipe (14) connected to an exhaust line (18, 20), at least two intake means (26, 28) comprising each a valve (32, 36) whose opening/closing is controlled by a dedicated actuating means (46, 48) and a pipe (30, 34). The method, during low load or medium load running of the engine: controls the closed position of exhaust valve (16) and controls one (36) of the intake valves so as to operate it as a burnt gas discharge valve.

Abstract: In a procedure to operate an internal combustion engine with an electrohydraulic valve control which comprises electrically activated oil control valves for hydraulic actuators for the actuation of charge-cycle valves, a motor control unit as well as an output stage unit, which is connected to the motor control unit via a data link, at least a limited operation of the internal combustion engine is made possible during a breakdown of the data bus between the motor control unit and the output stage unit, in that the output stage unit is transferred into an autonomous mode of operation during a breakdown of the data link to the motor control unit.

Abstract: A combined oil filtration and metering assembly for filtering and metering oil in an oil gallery, such as in a Lifter Oil Manifold Assembly of an internal combustion engine. The filtration and metering assembly includes a filtration element at an oil entrance leading to an internal chamber having a metering orifice as an outlet to a downstream portion of the oil gallery. Preferably the metering orifice has a diverging exit cone. Preferably, the assembly replaces directly a prior art metering valve in a LOMA socket without requiring retooling of the LOMA top plate. The assembly may be readily formed by molding of the filtration element into the oil entrance in an injection overmolding process.

Abstract: An oil gallery for a variable valve timing apparatus of a cylinder head includes an advance oil supply passage that fluidly connects an oil control valve hole and a variable valve timing journal, a retard oil supply passage that fluidly connects the oil control valve hole and the variable valve timing journal, and an oil chamber in at least one of the oil supply passages. The oil chamber may have a slanted ceiling that may slant upward toward an outlet opening of the oil chamber. The uppermost point of the ceiling may be positioned at the oil outlet. The lowermost point of the outlet opening may be above the bottom surface of the oil chamber.

Abstract: A variable valve lift apparatus of an engine includes: a control shaft; a driving arm rotatable around the control shaft by a cam of a camshaft; a first rocker arm rotatable around the control shaft, that is operated by the driving arm so as to drive a first valve through a first swing arm; a second rocker arm rotatable around the control shaft, that is operated by the driving arm so as to drive a second valve through a second swing arm; and a mediating device rotatable around the control shaft, that transmits a movement of the driving arm to the first and second rocker arms.

Abstract: An oil supply structure of a continuously variable valve timing apparatus includes: a first oil filter to receive and filter oil from a main gallery; a first oil control valve to receive oil from the first oil filter; a first continuously variable valve timing apparatus to receive oil from the first oil control valve; a second oil filter to receive and filter oil from the main gallery; a second oil control valve to receive oil from the second oil filter; a second continuously variable valve timing apparatus to receive oil from the second oil control valve; and an oil supply line in a cylinder head, that fluidly connects the main gallery, the oil filters, the oil control valves, and the continuously variable valve timing apparatuses. The cylinder head includes the oil supply line, and various holes for the components of the oil supply structure to be disposed therein.

Abstract: A variable valve apparatus includes a swing arm that includes a first body that pivots in response to rotation of an input cam, and a second body hingedly connected to the first body at a first connection. A connecting portion connects and disconnects the bodies at a second connection, in response to hydraulic pressure supplied thereto. When hydraulic pressure is not supplied to the connecting portion, the second body is connected to the first body and pivots along with the first body to open a valve.

Abstract: A variable valve timing mechanism-equipped engine is provided which allows a mount installing section and a hydraulic control valve of a variable valve timing mechanism to be positioned in a chain case without limitation of positioning of accessories such as a water pump, air conditioning compressor, power steering oil pump and alternator, and which simplifies an operating oil passage for the hydraulic control valve. In the variable valve timing mechanism-equipped engine, a mount installing section is positioned below an actuator cover section and is offset toward one side with respect to a cylinder axis, and intake- and exhaust-side hydraulic control valves are disposed sideward of the mount installing section with axes inclined toward a direction perpendicular to the crankshaft axis, the intake- and the exhaust-side hydraulic control valves overlapping one another.

Abstract: A method of starting an internal combustion engine for a vehicle having at least a hydraulic pump configured to be powered at least partially by a source other than the engine and an adjustable hydraulic actuator configured to be adjusted by hydraulic fluid of the hydraulic pump is provided. The method comprises during a first start of the engine, operating with the hydraulic actuator in a first position; and during a second start of the engine, operating with the hydraulic actuator in a second position, said second position different from said first position.

Abstract: A variable valve device modulates movement of a valve for internal combustion engine by using a hydraulic pressure. The variable valve device is controlled by a control device via a control valve that modulates hydraulic pressure supply to and discharge from the variable valve device. The control device offsets an operating amount of the control valve by an offset component that shifts the operating amount outside a dead band. The control device sets the offset component smaller as the hydraulic medium temperature increases. The control device sets the offset component smaller when a controlling direction coincides with a biasing direction of a biasing member than that when the controlling direction opposes to the biasing direction. Further, the control device cancels the offset component when the actual valve movement is sufficiently close to the target valve movement.

Abstract: In one aspect of the disclosure an internal combustion engine may be provided that may include a combustion chamber and a piston reciprocally moveable in the combustion chamber. The combustion chamber may have an intake port and a dual function port. The dual function port may be connected to an exhaust system and to an intake system. A method may be provided including opening a fluid connection between the intake system and the combustion chamber via the intake port as well as the dual function port during at least a part of an intake stroke of the piston. Instead of, or in addition, the method may include opening a fluid connection between the exhaust system and the combustion chamber via the dual function port during at least a part of the intake stroke of the piston.

Abstract: Actuators, and corresponding methods and systems for controlling such actuators, provide independent valve control with a large initial or opening force.

Abstract: Actuators, and corresponding methods and systems for controlling such actuators, provide independent valve control with a large initial or opening force.

Abstract: A variable valve lift apparatus includes a lift body that contacts a cam and a valve. The lift body has a first hole for receiving hydraulic pressure and a second hole for exhausting the hydraulic pressure. A spring is provided in the lift body. A hydraulic pressure supplying portion supplies the hydraulic pressure to the first hole, and a hydraulic pressure exhausting portion receives the hydraulic pressure from the second hole.

Abstract: A diagnostic system for an engine includes a pressure monitoring module that determines a plurality of first average pressure values and a plurality of second average pressure values of a fluid supply provided to a camshaft phaser. A diagnostic module identifies one of a plurality of cylinders associated with a failed variable valve lift mechanism based on the first and said second average pressure values. Each of the first and the second average pressure values respectively correspond to each of the plurality of cylinders.

Abstract: A hydraulic unit (5) for a cylinder head (2) of an internal combustion engine with a hydraulic, variable valve train (1) is provided. In the hydraulic unit, a high-pressure chamber (11), a medium-pressure chamber (12), and also a low-pressure chamber (16) used as a hydraulic medium reservoir are formed. The low-pressure chamber communicates merely via a choke opening (17) with the medium-pressure chamber, wherein the choke opening passes through a separating wall (18) extending between the low-pressure chamber and the medium-pressure chamber.

Abstract: A hybrid camshaft phaser comprising a conventional vane-type hydraulically-actuated phaser to which is coupled an electric motor and gear transmission. The transmission output shaft is coupled to the phaser rotor, optionally via an intermediate clutch mechanism. Under engine operating conditions in which the response of a hydraulic phaser is poor, the electric motor operates to augment the hydraulic actuation. Such conditions include at least low ambient temperatures at which oil viscosities are high, and high ambient temperatures and/or low engine speeds at which oil pressures are low. Preferably, at engine speeds above about 1500 rpm, the electric motor is de-energized.

Abstract: There is provided an engine for a small vehicle where driven sprockets, around which a cam chain for transmitting power from a crankshaft is wound, are provided at one end of camshafts that form a part of a valve system provided with hydraulic valve-operation mode changing mechanisms; and a valve-moving hydraulic pressure control device, which controls hydraulic pressure applied to the valve-operation mode changing mechanisms, is provided in the engine body. In the engine, it is possible to increase the degree of freedom in disposing the oil passage between the valve-operation mode changing mechanism and the valve-moving hydraulic pressure control device while avoiding the increase in the number of parts and assembly man-hours. A valve-moving hydraulic pressure control device is mounted on the side surface of the engine body on the side opposite to a cam chain in an axial direction of a camshaft.

Abstract: Systems and methods for selectively activating and deactivating gas exchange valves in a variable displacement internal combustion engine include a rocker arm having a positioning device that opposes movement of a lash adjustment device while deactivated to position a coupling hole of the rocker arm within a desired coupling range to facilitate coupling of the rocker arm during subsequent activation of an associated engine cylinder.

Abstract: A variable valve lift apparatus according to an exemplary embodiment of the present invention may include an outer part, an inner part disposed in the outer part and connected to a valve, a latching part that is disposed in the outer part and selectively connects the outer part and the inner part, a camshaft supplying torque, a low lift cam that is configured to the camshaft and selectively supplies torque to the inner part, and a high lift cam that is configured to the camshaft and supplies torque to the outer part.

Abstract: An engine is provided having an engine block, a cylinder head mounted to the engine block, a valve train mounted to the cylinder head, and a cam cover extending over the valve train and mounted to the cylinder head. A hydraulic system for providing a hydraulic fluid to the valve train is included. The hydraulic system has a first passage extending from the engine block through the cylinder head to the cam cover and connected to a second passage. The second passage extends along a length of the cam cover and is connected to an oil control valve. At least one control passage extends from the oil control valve through the cam cover to the valve train. The oil control valve is mounted to a port in the cam cover and extends into the cam cover in a direction along a width of the cam cover.

Abstract: A phase control valve, which supplies a drive hydraulic pressure to an advance chamber or a retard chamber, is integrated with a drain switch valve, which controls opening and closing of an advance drain control valve and opening and closing of a retard drain control valve, to form a solenoid spool valve. The advance drain control valve is provided in an advance check valve bypass passage, which bypasses an advance check valve, and is driven by a pilot hydraulic pressure to open and close the advance check valve bypass passage. The retard drain control valve is provided in a retard check valve bypass passage, which bypasses a retard check valve, and is driven by a pilot hydraulic pressure to open and close the retard check valve bypass passage.

Abstract: One of retard passages, which supplies working fluid to one of retard chambers, is a dedicated passage. The other remaining retard passages, which supply the working fluid to the other remaining retard chambers, are branch passages, which are branched from a retard passage that serves as a supply passage. With this construction, a flow quantity of working fluid per unit time supplied from the one of retard passages to the one of retard chambers becomes larger than a flow quantity of working fluid per unit time supplied from the other remaining retard passages to the other remaining retard chambers. Thus, the one of retard chambers can be filled with the working fluid earlier than the other remaining retard chambers.

Abstract: An electromagnetic hydraulic valve (1), which including an electromagnet (2) with an armature (3) and of a valve housing (4) with an axial bore (5) and a piston valve (6) located therein is provided. The valve housing (4) includes several annular grooves (8, 9, 10) in which several radial openings (11, 12, 13) are located, which open into the axial bore (5), through which the hydraulic valve (1) has a fluid connection with a pressure connection (P), a tank connection (T) and two consumer connections (A, B). The piston valve (6) is acted upon by the armature (3) of electromagnet (2) and includes two ring-shaped control sections (14, 15), which connect alternatively the pressure connection (P) and the tank connection (T) with one of the consumer connections (A, B) through axial movement of piston valve (6). According to the invention, the radial openings (11, 12, 13) in valve housing (4) are provided as windows having a rectangular cross section.

Abstract: An internal combustion engine having a cylinder block defining a plurality of cylinders at least half of which are selectively deactivatable by a plurality of switching hydraulic lifters. A source of pressurized oil is provided. Additionally, at least one solenoid-actuated hydraulic control valve operates to selectively communicate pressurized oil from the source of pressurized oil to actuate the plurality of switching hydraulic lifters thereby deactivating the selectively deactivatable cylinders. The number of the solenoid-actuated hydraulic control valves is fewer than the number of selectively deactivatable cylinders.

Abstract: In a method for operating an electrohydraulic valve control system of an internal combustion engine, the electrohydraulic valve control system comprising at least one gas exchange valve actuator and a gas exchange valve, which is hydraulically actuated by it, an actuation characteristic is acquired during the operation of the internal combustion engine while the gas exchange valve is being actuated and is compared with a reference actuation characteristic, which describes a nominal characteristic of the gas exchange valve actuator.

Abstract: A valve control system for an internal combustion engine includes a valve actuation system. The valve actuation system includes lift control valves that actuate at least one of an intake valve and an exhaust valve between N open lift modes, where N is an integer greater than one. A control module enables transitioning of at least one of the intake valve and the exhaust valve between the open lift modes. The control module synchronizes transitions between the N open lift modes with crankshaft and valvetrain timing. The control module generates an engine position synchronization signal based on the transitioning.

Abstract: Systems and methods of actuating two engine valves associated with a common engine cylinder using one or more lost motion systems and one or more control valves are disclosed. The control valves are capable of selectively trapping hydraulic fluid in the lost motion systems for auxiliary engine valve actuations and selectively releasing the hydraulic fluid to default to cam controlled valve seating of the engine valves. The systems may provide a combination of main exhaust, compression release, exhaust gas recirculation and early exhaust valve opening in preferred embodiments.

Abstract: A valve drive (1) of an internal combustion engine which is used to actuate a gas exchange valve (6) is provided. Displacement of the valve takes place when a cam (9) is lifted and when a hydraulic force applying device (12) is lifted. A piston (13) of the force applying device can be displaced from a first end position (A) to a second end position by feeding a hydraulic medium, which can be pressure-adjusted, from a hydraulic medium line (24) into a pressure chamber (21). The pressure chamber (21) can be connected to the hydraulic medium line (24) via a shut-off element (20) which is open towards the pressure chamber (21) and which is arranged in the housing (15) and also by means of at least one passage (26) in the housing (15). The passage (26) is at least partially blocked by an external casing surface (16) of the piston (13) in the first end position (A) thereof.

Abstract: A switchable valvetrain system is provided having a control unit and a pressure regulator valve responsive to control signals from the control unit. A pressurized fluid source is provided in communication with the pressure regulator valve. A switchable valvetrain component having a latching mechanism and lubrication circuit in selective communication with the pressurized fluid source through the pressure regulator valve is also provided. The pressure regulator valve is operable to selectively and variably communicate fluid pressure from the pressurized fluid source to the latching mechanism and the lubrication circuit in response to control signals from the control unit. A method of operating the switchable valvetrain system is also provided.

Abstract: A system and method for actuating one or more engine valves is provided. In particular, systems and methods for providing variable valve actuation to improve engine performance are provided. Embodiments of the present invention may be used in conjunction with positive power, engine braking, and/or exhaust gas recirculation operation of an internal combustion engine. In one embodiment, the system comprises: a valve train element; a housing disposed intermediate the valve train element and the engine valve; an outer piston slidably disposed in a bore formed in the housing, the outer piston having a cavity formed therein; an inner piston slidably disposed in the outer piston cavity; and a valve in communication with the outer piston cavity, the valve having more than one position, wherein the position of the valve determines the timing of the engine valve event.