Patent ID: 8413638
Filing Date: 2013-04-09
Classification: F02D,F02M,F16K

Abstract:
1. A method of operating a directly actuated valve that comprises a strain-type actuator operable by an actuator driver to actuate a valve member to travel between a closed position in which said valve member contacts a valve seat and an open position in which said valve member is spaced apart from said valve seat, said method comprising transmitting displacements from said strain-type actuator to said valve member, applying a pre-load compressive stress to said actuator, and limiting to less than predetermined limits at least one of: (a) acceleration and deceleration of said valve member when moving between said open positions and said closed position, and (b) velocity of said valve member immediately before contacting said valve seat, to maintain a compressive stress on said actuator that is greater than a predetermined minimum stress.