초록 ▼

A method of controlling a valve actuation system is provided. An intake cam assembly is operated to move an intake valve between a first position and a second position. An exhaust cam assembly is operated to move an exhaust valve between a first position a second position. An engine brake is operate

A method of controlling a valve actuation system is provided. An intake cam assembly is operated to move an intake valve between a first position and a second position. An exhaust cam assembly is operated to move an exhaust valve between a first position a second position. An engine brake is operated to selectively move the exhaust valve from the first position towards the second position when a piston is at or near a top-dead-center position of a compression stroke. At least one operating parameter of the engine is sensed. A desired intake valve actuation period is determined based on the at least one operating parameter. A valve actuator is engaged with the intake valve to prevent the intake valve from returning to the first position in response to operation of the intake cam assembly. The valve actuator is released to allow the intake valve to return to the first position at the end of the determined valve actuation period.

대표청구항 ▼

A method of controlling a valve actuation system is provided. An intake cam assembly is operated to move an intake valve between a first position and a second position. An exhaust cam assembly is operated to move an exhaust valve between a first position a second position. An engine brake is operate

A method of controlling a valve actuation system is provided. An intake cam assembly is operated to move an intake valve between a first position and a second position. An exhaust cam assembly is operated to move an exhaust valve between a first position a second position. An engine brake is operated to selectively move the exhaust valve from the first position towards the second position when a piston is at or near a top-dead-center position of a compression stroke. At least one operating parameter of the engine is sensed. A desired intake valve actuation period is determined based on the at least one operating parameter. A valve actuator is engaged with the intake valve to prevent the intake valve from returning to the first position in response to operation of the intake cam assembly. The valve actuator is released to allow the intake valve to return to the first position at the end of the determined valve actuation period. e cylinder, said element being provided with a pressure piston longitudinally slidable in a cylinder, which piston is adjacent to a pressure chamber into which opens a pressure channel departing from a port in the wall face of the force application element, a fixed pressure line opening into the guide cylinder in the area of the port, which line can be subjected to hydraulic high pressure permitting hydraulic activation of the valve, wherein a permanent flow connection is provided between pressure line and pressure channel independently of the position of the force application element. 2. A valve train according to claim 1, wherein an end of the pressure line opening into the guide cylinder and the port in the wall face of the force application element are designed to be overlapping in every position. 3. A valve train according to claim 1, wherein the force application element can perform a lift corresponding to the cam lift, wherein a recess is provided between pressure line and pressure channel which communicates with both pressure line and pressure channel, the height of which recess, as measured in the direction of the lift, will correspond to at least the maximum lift of the force application element. 4. A valve train according to claim 3, wherein the recess is configured at least partially by a space in the guide cylinder. 5. A valve train according to claim 3, wherein the recess is configured at least partially by a space in the exterior wall face of the force application element. 6. A valve train according to claim 1, wherein the force application element is located between the cam and the lifting valve. 7. A valve train according to claim 6, wherein the force application element is coaxial with the valve. 8. A valve train according to claim 6, wherein the force application element is configured as a cup-shaped tappet. 9. A valve train according to claim 1, wherein the force application element is configured as part of a valve arm bearing block supporting a valve arm for actuation of the lifting valve. 10. A valve train according to claim 1, wherein the force application element is located between the cam and a valve arm for actuation of the lifting valve. 11. A valve train according to claim 1, wherein the pressure line is connected to an external pressure generating unit comprising at least one pump, and at least one pressure tank with at least one pressure regulator, and at least one pressure control element. 12. A valve train according to claim 11, wherein the pressure control element is configured as an electromechanical element with at least one electromechanically actuated valve. 13. A valve train according to claim 11, wherein the pressure control element is configured as a piezo-mechanical element with at least one piezomechanically actuated valve. 14. A valve train according to claim 11, wherein several lifting valves can be actuated by means of one and the same pressure control element. 15. A valve train according to claim 11, wherein the pressure control element is configured as a 3/2-way valve. 16. A valve train according to claim 11, wherein the working medium or control medium of the pressure generating unit is a liquid selected from the group consisting of water, fuel, and lubricating oil. 17. A valve train according to claim 11, wherein the pressure generating unit is part of a further subsystem of the engine other than the valve train. 18. A valve train according to claim 17, wherein the pressure tank is part of a fuel injection system. 19. A valve train according to claim 17, wherein the pressure tank is part of an hydraulic gear system of the vehicle. 20. A valve train according to claim 17, wherein the pressure tank is part of a hydraulic braking system of the vehicle. 21. A valve train according to claim 17, wherein the pressure tank is part of a coolant circulation system of the vehicle. 22. A valve train according to claim 11, wherein the pressure generating unit has a high pressure level and a