Intake valve closing hydraulic adjuster

摘要

A mechanism (40) for enabling an engine cylinder valve (18) to close at various times during engine cycles has a hydraulic actuator (58) and a control valve (60) controlling the hydraulic actuator a) to constrain a pivot axis of a valve rocker (52) against relocation while the cylinder valve is being forced increasingly open, and b) to release the constraint after the cylinder valve has been forced open for enabling the pivot axis to relocate so that the intake valve can close early thereby providing early IVC. A hydraulic snubber (64) snubs closing motion of the cylinder valve through a scheduling geometry to a hydraulic accumulator (62). The control valve opens to the accumulator to allow the rocker pivot axis to relocate and provide early IVC and closes to return the pivot axis to a location that doesn't provide early IVC.