| 摘要 |
A valve actuation assembly (40) for operating a valve of an engine (10) with adjustable closing times is disclosed. The valve actuation assembly (40) comprises a camshaft system comprising a camshaft (56) with a cam lobe (58), and a push rod (48) interacting with the cam lobe (58) to be displaced, during a rotation of the camshaft (56), in accordance with an actuation movement including a lifting movement (L) and a return movement (R). A rocker arm (46) is rotatably mounted to a rocker shaft (50) to perform a pivot movement and comprises a push rod section (46B) for interacting with the push rod (48), which provides a lifting force (Fl) onto the rocker arm (46) during the lifting movement (L), and a valve actuation section (46A) for operating an engine valve (30). A biasing force providing unit (52) provides a biasing force (Fb) counteracting the lifting force (Fl) and enforcing the return movement (R). A valve timing adjustment system (60) is configured to, in a blocking state (B), provide a delay force (Fd) acting against the biasing force (Fb) to block the rocker arm (46), thereby temporarily disengaging the rocker arm (46) from the push rod (48). Respective adaptation of valve closing times allows providing, for example, a filling optimized part load operation, while having a Miller operation at full load. |
