SPOOL VALVE CONTROL OF AN ELECTROHYDRAULIC CAMLESS VALVETRAIN

摘要

An engine valve assembly (10) within an electrohydraulic camless valvetrain cooperates with a hydraulic system (8) having a low pressure branch (70) and a high pressure branch (68) to selectively open and close engine valve (12). Engine valve (12) is affixed to a valve piston (16) within a piston chamber (18). A volume (42) below piston (16) is connected to high pressure branch (68) and a volume (20) above piston (16) is selectively connected to the high pressure branch (68) or the low pressure branch (70) via a spool valve (34), to effect engine valve opening and closing. A motor (60) effects the movement of the spool valve (34).