Abstract: A variable valve actuation system to actuate and control the seating velocity of an internal combustion engine valve is disclosed. The system may comprise a rocker arm that includes first, second and third contact surfaces. The first contact surface may contact the engine valve. A hydraulic lost motion system may contact the rocker arm at the second contact surface, and a mechanical valve train element may contact the rocker arm at the third contact surface. The lost motion system may include a slave piston with a valve seating device incorporated therein. The lost motion system and the mechanical valve train element may be provided side by side at the end of the rocker arm opposite that of the engine valve.

Abstract: A lost motion engine valve actuation system and method of actuating an engine valve are disclosed. The system may comprise a valve train element, a pivoting lever, a control piston, and a hydraulic circuit. The pivoting lever may include a first end for contacting the control piston, a second end for transmitting motion to a valve stem and a means for contacting a valve train element. The amount of lost motion provided by the system may be selected by varying the position of the control piston relative to the pivoting lever. Variation of the control piston position may be carried out by placing the control piston in hydraulic communication with a control trigger valve and one or more accumulators. Actuation of the trigger valve releases hydraulic fluid allowing for adjustment of the control piston position. Means for limiting valve seating velocity, filling the hydraulic circuit upon engine start up, and mechanically locking the control piston/lever for a fixed level of valve actuation are also disclosed.

Abstract: Apparatus and methods for hydraulic valve actuation of engine valves are disclosed. An exemplary embodiment of the present invention may include a plurality of slave piston assemblies that impart motion to the engine valves, wherein the motion is operable to open and close the engine valves. A dual diameter master piston assembly may be used to drive the plurality of slave pistons. The dual diameter master piston assembly may be divided into two or more elements with, for example, a spring bias or a button and T-slot assembly to hold the two elements together.

Abstract: An engine valve actuation system for an internal combustion engine is disclosed. The valve actuation system may include a longitudinally extending link member pivotally attached to an engine member. A longitudinally extending finger follower may be pivotally attached to the link member. The finger follower may include first and second contact surfaces spaced longitudinally from each other. A lost motion piston may contact the first contact surface of the finger follower and an engine valve assembly may contact the second contact surface of the finger follower. A means for receiving valve actuation motion, such as a cam follower, may be incorporated into the finger follower. A valve seating device may contact a third contact surface located on the link member, and a biasing spring may contact a fourth contact surface on the finger follower.

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.

Abstract: Apparatus and methods for hydraulic valve actuation of engine valves are disclosed. An exemplary embodiment of the present invention may include a plurality of slave piston assemblies that impart motion to the engine valves, wherein the motion is operable to open and close the engine valves. A dual diameter master piston assembly may be used to drive the plurality of slave pistons. The dual diameter master piston assembly may be divided into two or more elements with, for example, a spring bias or a button and T-slot assembly to hold the two elements together.

Abstract: An engine valve actuation system for an internal combustion engine is disclosed. The valve actuation system may include a longitudinally extending link member pivotally attached to an engine member. A longitudinally extending finger follower may be pivotally attached to the link member. The finger follower may include first and second contact surfaces spaced longitudinally from each other. A lost motion piston may contact the first contact surface of the finger follower and an engine valve assembly may contact the second contact surface of the finger follower. A means for receiving valve actuation motion, such as a cam follower, may be incorporated into the finger follower. A valve seating device may contact a third contact surface located on the link member, and a biasing spring may contact a fourth contact surface on the finger follower.

Abstract: Methods and systems for retaining hydraulic fluid in a hydraulic valve actuation system adapted to be installed on an internal combustion engine are disclosed. The system may include a hydraulic fluid supply connected by one or more passages to a fluid accumulator and a hydraulic valve actuator. The one or more passages may include a retaining portion elevated above portions of the fluid accumulator and/or the hydraulic valve actuator. The retaining portion may include an air vent and thus prevent back flow of all the fluid in the accumulator and/or hydraulic valve actuator to the fluid supply during periods that the engine is shut off. Retention of hydraulic fluid in the system may be further enhanced during engine shut off by selectively controlling the release of hydraulic fluid from the hydraulic valve actuator during the engine shut off process.

Abstract: Lost motion systems and methods for providing engine valves with variable valve actuation for engine valve events are disclosed. The system may include a master piston hydraulically linked to a slave piston, and a dedicated cam operatively connected to the master piston. The slave piston may be disposed substantially perpendicular to the master piston in a common housing. The slave piston is adapted to actuate one or more engine valves. The slave piston may incorporate an optional valve seating assembly into its upper end. A trigger valve may be operatively connected to the master-slave hydraulic circuit to selectively release and add hydraulic fluid to the circuit.

Abstract: Lost motion systems and methods for providing engine valves with variable valve actuation for engine valve events are disclosed. The system may include a master piston hydraulically linked to a slave piston, and a dedicated cam operatively connected to the master piston. The slave piston may be disposed substantially perpendicular to the master piston in a common housing. The slave piston is adapted to actuate one or more engine valves. The slave piston may incorporate an optional valve seating assembly into its upper end. A trigger valve may be operatively connected to the master-slave hydraulic circuit to selectively release and add hydraulic fluid to the circuit.

Abstract: The present invention provides a hydraulic actuator for operating an engine valve, which includes a means for controlling the seating velocity of the valve. The design allows for free, unrestricted movement of the actuator piston during opening of the engine valve, and an unrestricted return of the piston and valve until the valve is within a predetermined distance of the valve seat. Once within this predetermined range, the return velocity of the actuator piston and engine valve are limited by the rate at which a fluid may escape through a restriction. The restriction is calibrated to provide the desired maximum valve seating velocity. The invention also provides for automatic lash adjustment.

Abstract: The present invention provides a hydraulic actuator for operating an engine valve, which includes a means for controlling the seating velocity of the valve. The design allows for free, unrestricted movement of the actuator piston during opening of the engine valve, and an unrestricted return of the piston and valve until the valve is within a predetermined distance of the valve seat. Once within this predetermined range, the return velocity of the actuator piston and engine valve are limited by the rate at which a fluid may escape through a restriction. The restriction is calibrated to provide the desired maximum valve seating velocity. The invention also provides for automatic lash adjustment.

Abstract: An engine valve actuation system is disclosed, which is capable providing compression release engine braking in combination with exhaust gas recirculation while maintaining main exhaust and main intake valve events of constant magnitude during both positive power and engine braking. The system is also capable of providing a constant level of desired overlap between main exhaust and main intake valve events during both positive power and engine braking. The system may provide the foregoing functions by using first and second valve actuation subsystems to provide the full spectrum of exhaust valve motions. Both the first and second subsystems may receive an input motion from a valve train element. The first subsystem operates only when the engine braking system is enabled. The second subsystem operates both during positive power and during engine braking.

Abstract: An injector for a common rail fuel injection system employs a solenoid operated valve configuration which functions to control the amount of filling by regulating the start of filling and the end of filling between the injection events. In some embodiments, a three-way solenoid valve is employed. The start of injection is controlled by a control piston. An intensifier piston is employed to increase the injection pressure. A pilot piston assembly may also be employed to regulate the shape of the injection.

Abstract: An electronic unit injector employs an expandable chamber which expands as pressure in the injector increases between a pair of threshold pressures. The expansion of the chamber results in a two-phase rate of injection of the injector whereby the initial injection rate is significantly lower than the second injection rate. In one embodiment, the expandable chamber is formed by a pin which is displaceable in a cap mounted to the injector body. The pin bottoms against the cap to define the phase transition.

Abstract: A fuel injection nozzle and holder assembly of conventional construction is made leakless by eliminating the leakoff passages from the spring chamber. An unreasonable buildup of leakage fuel pressure in the spring chamber is prevented by relieving the pressure in the fuel delivery passages between injection intervals to permit leakage from the spring chamber and a stabilization of the spring pressure. A continuously open passage is provided between the spring chamber and the valve bore to prevent a sealing of the spring chamber by the nozzle valve during the injection interval and thus provide a predictable spring chamber pressure augmenting the nozzle closing force of the spring.