Selective resetting lost motion engine valve train components
Systems and related methods include a rocker arm having integrated components, including a lost motion actuator piston and components for resetting the lost motion actuator piston to provide normal valve closing or late valve closing. Selective reset is facilitated by a reset piston and a blocking piston disposed in a hydraulic circuit including a reset passage. In a non-resetting mode of operation, the blocking piston may block oil flow within the reset passage, regardless of the position of the reset piston, which facilitates late valve closing. An alternative embodiment includes a blocking sleeve disposed concentrically relative to the reset piston.
1. A valve actuation system for conveying motion from a motion source to at least one engine valve in a valve train in an internal combustion engine comprising:
a housing adapted to support components of the system;
a lost motion component disposed in the housing for selectively conveying motion from the motion source to the housing, the lost motion component adapted to absorb motion provided from the motion source in a lost motion state;
a reset component for resetting the lost motion component to the lost motion state; and
a reset blocking component for selectively preventing reset of the lost motion component.
2. The valve actuation system of claim 1 , further comprising a working fluid circuit, at least partially defined in the housing, for controlling the flow of working fluid to the lost motion component.
3. The valve actuation system of claim 2 , wherein the working fluid circuit further comprises a working fluid supply and a backflow prevention component for preventing backflow of working fluid from the lost motion component to the working fluid supply.
4. The valve actuation system of claim 3 , wherein the backflow control component is a check valve disposed in the working fluid circuit.
5. The valve actuation system of claim 2 , wherein the working fluid circuit further comprises a flow control component for controlling a flow of working fluid from the reset component.
6. The valve actuation system of claim 2 , wherein the reset component and reset blocking component form part of the working fluid circuit.
7. The valve actuation system of claim 2 , wherein the working fluid circuit further comprises a working fluid circuit control component for controlling the lost motion component based on at least one engine parameter, including engine load, engine speed, engine temperature and exhaust temperature.
8. The valve actuation system of claim 1 , wherein the motion source includes a valve closing profile for imparting valve closing motion to the valve train, and wherein the reset component is arranged to reset the lost motion component to absorb at least a portion of the valve train valve closing motion.
9. The valve actuation system of claim 1 , wherein the reset component comprises a reset valve.
10. The valve actuation system of claim 1 , wherein the reset blocking component comprises a reset blocking valve.
11. The valve actuation system of claim 1 , wherein the housing is a rocker arm and wherein the reset component and reset blocking component are integrated into the rocker arm.
12. The valve actuation system of claim 1 , wherein the housing is a rocker arm mounted on a rocker shaft and wherein the reset component is arranged to reset the lost motion component based on an angular position of the rocker arm relative to the rocker shaft.
13. The valve actuation system of claim 1 , wherein the reset component comprises a reset piston, and wherein the reset blocking component comprises a sleeve cooperating with the reset piston.
14. The valve actuation system of claim 1 , further comprising an internal combustion engine, the internal combustion engine further comprising a contact surface, wherein the housing is arranged to move relative to the contact surface and wherein the reset component is adapted to engage the contact surface as the housing moves relative to the contact surface.
15. The valve actuation system of claim 1 , wherein the housing comprises a rocker arm, the system further comprising a rocker arm biasing component for biasing the rocker arm.
16. The valve actuation system of claim 1 , wherein the lost motion component further comprises an actuator piston and a lost motion biasing component for biasing the actuator piston towards an extended position.
17. The valve actuation system of claim 16 , further comprising a lash adjustment component for setting a stroke of the lost motion component.
18. The valve actuation system of claim 1 , further comprising at least one blocking component actuator to actuate the blocking component.
19. The valve actuation system of claim 1 , wherein the lost motion component further comprises an actuator piston and a motion limiter for limiting the motion of the actuator piston.
20. A method of controlling valve motion in a valve actuation system in an internal combustion engine, the valve actuation system comprising: at least one engine valve in a valve train in an internal combustion engine; a housing adapted to support components of the valve actuation system; a lost motion component disposed in the housing for selectively conveying motion from a motion source to the housing, the lost motion component adapted to absorb motion provided from the motion source in a lost motion state; a high-pressure hydraulic reset component for resetting the lost motion component to the lost motion state; and a reset blocking component for selectively preventing reset of the lost motion component, the method comprising:
operating the high-pressure hydraulic reset component to reset the lost motion component and cause the lost motion component to absorb motion from the motion source; and
operating the reset blocking component to block flow of high-pressure hydraulic fluid from the high-pressure hydraulic reset component and to thereby block reset of the lost motion component.
21. The method of claim 20 , wherein the step of operating the high-pressure hydraulic reset component comprises absorbing late valve closing motion provided by the motion source, and wherein the step of operating the reset blocking component causes late valve closing motion.