Patent attributes
The invention provides a valvetrain configuration in an internal combustion engine in which a plurality of two-step rockers enable the engine poppet valves to switch between two lift profiles. In addition, a lost-motion stationary lash adjuster enables the deactivation of the engine poppet valve. The integration of a two-step rocker with a deactivating stationary lash adjuster yields a better control of the combustion process, under different engine operating conditions than what is achievable with either one of these actuators acting alone. Preferably, the locking and unlocking of the two-step rocker arm and deactivating stationary lash adjuster is controlled by two on/off hydraulic valves in a hydraulic circuit, and a piloted check valve prevents hard landings between stationary and moving components within the stationary hydraulic lash adjuster.
