公开(公告)号：WO1993020337A1

公开(公告)日：1993-10-14

申请号：PCT/US1993002406

申请日：1993-03-17

Applicant: SIEMENS AUTOMOTIVE L.P.

Inventor： SIEMENS AUTOMOTIVE L.P. ,  ROBNETT, James, T. ,  MOLITOR, Mark, Richard

IPC: F01L09/02

CPC classification number: F01L13/0031 ,  F01L1/16 ,  F01L1/255

Abstract: A damping mechanism for a lost motion hydraulic actuator utilizes a thin edge orifice (66) in cooperation with a communication passageway (62) between the upper (46) and lower (48) chambers and controls the damping of the upper piston (38) on closure. The upper piston is operatively connected to the engine valve of an internal combustion engine. A communication port (64) from the upper chamber to the communication passageway is closed off as the upper piston returns to its normal position forcing the flow of the hydraulic fluid through the thin edge orifice. In this manner the viscosity of the hydraulic fluid does not control the damping of the actuator and the noise factor is substantially reduced.