Hydraulic valve actuation systems and methods to provide variable lift for one or more engine air valves
Hydraulic valve actuation systems and methods to provide variable lift for one or more engine air valves by way of a variable position hard stop. Various embodiments are disclosed, including embodiments controlling lift by providing a choice of two different fixed stops, three different fixed stops, stops continuously variable throughout a range of lifts, and a fixed stop and stops continuously variable throughout a range of lifts. The valves controlled by a variable position hard stop may be a single engine intake or exhaust valve, or multiple valves of any number, and of either intake or exhaust valves or both, or of one intake or one exhaust valve for one or more cylinders in engines having more than one intake or exhaust valve per cylinder. Dashpot deceleration of engine valve velocity on opening to the hard stop and on engine valve closure is disclosed, as are other aspects and embodiments of the invention.
1. In a hydraulic engine valve actuation system, a hydraulic engine valve actuator coupleable to a source of actuation fluid under a first pressure to open an engine valve and coupleable to actuation fluid under a second pressure less than the first pressure to allow the engine valve to close, the hydraulic engine valve actuator having a plurality of progressive orifices coupling the hydraulic engine valve actuator to the actuation fluid under a second pressure that are progressively closed as the engine valve approaches the engine valve closed position to decelerate the engine valve, and a check valve configured to bypass the progressive orifices when actuation fluid under the first pressure is coupled to the hydraulic engine valve actuator to open an engine valve.
2. In the hydraulic engine valve actuation system of claim 1 , at least one pin acting under actuation fluid under the first pressure to urge the engine valve toward the closed position.
3. In the hydraulic engine valve actuation system of claim 2 , the maximum engine valve lift is defined by the at least one pin reaching a limit of its travel.
4. In the hydraulic engine valve actuation system of claim 3 , the at least one pin being slideable within a respective cylinder, the cylinder having progressive orifices coupled to the actuation fluid under pressure that are progressively closed as the engine valve approaches its maximum lift to decelerate the engine valve.
5. In the hydraulic engine valve actuation system of claim 4 , wherein the respective cylinder is in an adjustable lift adjusting member, whereby the maximum engine valve lift may be varied.
6. In a hydraulic engine valve actuation system, a hydraulic actuator coupled to a source of hydraulic fluid under pressure to encourage an engine valve to a closed position, the hydraulic actuator having a plurality of progressive orifices coupling the hydraulic actuator to the hydraulic fluid under pressure that are progressively closed as an engine valve approaches an engine valve open position to decelerate the engine valve, and a check valve configured to bypass the progressive orifices when the engine valve moves toward the engine valve closed position.
7. The hydraulic actuator of claim 6 further comprised of a variable position hard stop defining engine valve lift at the engine valve open position.
8. In a hydraulic engine valve actuation system, a hydraulic engine valve actuator coupleable to a source of actuation fluid under a first pressure to open an engine valve and coupleable to actuation fluid under a second pressure less than the first pressure to allow the engine valve to close, the hydraulic engine valve actuator having progressive orifices coupling the hydraulic engine valve actuator to the actuation fluid under a second pressure that are progressively closed as the engine valve approaches the engine valve closed position to decelerate the engine valve, and a check valve configured to bypass the progressive orifices when actuation fluid under the first pressure is coupled to the hydraulic engine valve actuator to open an engine valve.
9. In the hydraulic engine valve actuation system of claim 8 , at least one pin acting under actuation fluid under the first pressure to urge the engine valve toward the closed position.
10. In the hydraulic engine valve actuation system of claim 9 , the maximum engine valve lift is defined by the at least one pin reaching a limit of its travel.
11. In the hydraulic engine valve actuation system of claim 10 , the at least one pin being slideable within a respective cylinder, the cylinder having progressive orifices coupled to the actuation fluid under pressure that are progressively closed as the engine valve approaches its maximum lift to decelerate the engine valve.
12. In the hydraulic engine valve actuation system of claim 11 , wherein the respective cylinder is in an adjustable lift adjusting member, whereby the maximum engine valve lift may be varied.
13. In a hydraulic engine valve actuation system, a hydraulic actuator coupled to a source of hydraulic fluid under pressure to encourage an engine valve to a closed position, the hydraulic actuator having progressive orifices coupling the hydraulic actuator to the hydraulic fluid under pressure that are progressively closed as an engine valve approaches an engine valve open position to decelerate the engine valve, and a check valve configured to bypass the progressive orifices when the engine valve moves toward the engine valve closed position.
14. The hydraulic actuator of claim 13 further comprised of a variable position hard stop defining engine valve lift at the engine valve open position.