Compact lost motion system for variable value actuation
View Patent ↗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.
1. A valve actuation system comprising:
a lost motion system having a master piston bore and a slave piston bore, wherein the master piston bore and the slave piston bore intersect, a master piston slidably disposed in the master piston bore, wherein the master piston is adapted to receive an input motion, and a slave piston slidably disposed in the slave piston bore, wherein the slave piston is adapted to actuate one or more engine valves; and
a rocker arm having a first contact portion adapted to provide input motion to the master piston and a second contact portion adapted to provide selective actuation for the one or more engine valves.
2. The system of claim 1 further comprising an engine valve bridge disposed between the one or more engine valves and the second contact portion.
3. The system of claim 1 wherein a lash space is selectively provided between the second contact portion and the one or more engine valves.
4. The system of claim 1 wherein the lost motion system further comprises:
a hydraulic supply passage communicating with the slave piston bore; and
a trigger valve operatively connected to the hydraulic supply passage.
5. The system of claim 1 wherein the slave piston further comprises means for seating the one or more engine valves.
6. The system of claim 5 wherein the means for seating further comprises means for selectively preventing the one or more engine valves from seating.
7. The system of claim 1 wherein the slave piston further comprises a valve seating assembly.
8. The system of claim 7 further comprising:
a trigger valve; and
a hydraulic passage extending between the trigger valve and the valve seating assembly.
9. The system of claim 8 further comprising:
a hydraulic fluid supply passage communicating with the master piston bore; and
a check valve disposed in the hydraulic fluid supply passage.
10. The system of claim 4 wherein the trigger valve is adapted to provide high speed actuation.
11. The system of claim 4 further comprising a fluid accumulator in hydraulic communication with the trigger valve.
12. The system of claim 1 wherein the master piston bore and the slave piston bore extend in directions substantially perpendicular to each other.
13. The system of claim 6 wherein the means for selectively preventing the one or more engine valves from seating further comprises means for providing bleeder braking.
14. The system of claim 1 further comprising:
a second rocker arm disposed adjacent to the rocker arm, said second rocker arm having a rocker shaft receiving end, an actuation end, and an intermediate portion between the rocker shaft receiving end and the actuation end,
wherein the rocker arm second contact portion selectively contacts the second rocker arm intermediate portion, and the second rocker arm actuation end is disposed between the slave piston and the one or more engine valves.
15. The system of claim 1 further comprising:
a second rocker arm disposed adjacent to the rocker arm, said second rocker arm having a rocker shaft receiving end, an actuation end, and an intermediate portion between the rocker shaft receiving end and the actuation end,
wherein the rocker arm second contact portion selectively contacts the second rocker arm intermediate portion, and the second rocker arm actuation end is disposed between the slave piston and a valve bridge associated with the one or more engine valves.
16. A valve actuation system comprising:
a lost motion system having a master piston bore and a slave piston bore, wherein the master piston bore and the slave piston bore extend axially in directions substantially perpendicular to each other, a master piston slidably disposed in the master piston bore, wherein the master piston is adapted to receive an input motion, and a slave piston slidably disposed in the slave piston bore, wherein the slave piston is adapted to actuate one or more engine valves; and
a rocker arm having a first contact portion adapted to provide input motion to the master piston and a second contact portion adapted to selectively actuate the one or more engine valves.
17. The system of claim 16 further comprising an engine valve bridge disposed between the one or more engine valves and the second contact portion.
18. The system of claim 16 wherein a lash space is selectively provided between the second contact portion and the one or more engine valves.
19. The system of claim 16 wherein the lost motion system further comprises:
a hydraulic supply passage communicating with the slave piston bore; and
a trigger valve operatively connected to the hydraulic supply passage.
20. The system of claim 16 wherein the slave piston further comprises means for seating the one or more engine valves.
21. The system of claim 20 wherein the means for seating further comprises means for selectively preventing the one or more engine valves from seating.
22. A method of providing variable valve actuation for an internal combustion engine valve comprising the steps of:
actuating the engine valve for a valve event during at least a positive power mode of engine operation using a lost motion system;
discontinuing actuating the engine valve for the valve event during at least a positive power mode of engine operation using the lost motion system; and
actuating the engine valve for the valve event during at least a positive power mode of engine operation using a rocker arm.
23. The method of claim 22 wherein the step of discontinuing actuating the engine valve is responsive to a failure in the lost motion system.
24. The method of claim 22 wherein the step of discontinuing actuating the engine valve is responsive to selective deactivation of the lost motion system.
25. The method of claim 22 further comprising the step of providing a lower amount of lift for the valve event using the rocker arm as compared to the amount of lift provided for the valve event using the lost motion system.
26. The method of claim 22 further comprising the step of providing different valve event timing using the rocker arm as compared to the valve event timing provided using the lost motion system.