Electrohydraulic valve controller

Abstract

An electrohydraulic valve controller ( 1 ) for the variable actuation of a gas exchange valve ( 2 ) of an internal combustion engine is provided that includes a hydraulic valve ( 13 ), and for the purpose of emergency running properties, an additional hydraulic valve ( 19 ).

1 . Electrohydraulic valve controller for variable actuation of a gas-exchange valve of an internal combustion engine, comprising
 a master piston driven by a camshaft,   a slave piston adapted to drive the gas-exchange valve,   a pressure space with variable volume defined by the master piston and the slave piston,   a pressure-relief space connected to a hydraulic medium supply of the internal combustion engine,   a control line connecting the pressure space to the pressure-relief space and an electrically controllable hydraulic valve that is arranged therein and adapted to open up or block a hydraulic medium flow through the control line,   a bypass line connecting the pressure space to the pressure-relief space and a non-return valve arranged therein adapted to openup a hydraulic medium flow through the bypass line into the pressure space and to block it into the pressure-relief space,   that the valve controller comprises an additional hydraulic valve that is arranged in the control line between the hydraulic valve and the pressure-relief space and is adapted to block, in case of the hydraulic valve being incorrectly open, the hydraulic medium flow through the control line into the pressure-relief space.   
     
     
         2 . Electrohydraulic valve controller according to  claim 1 , wherein the hydraulic valve has a non-energized open construction. 
     
     
         3 . Electrohydraulic valve controller according to  claim 2 , wherein the additional hydraulic valve has an electrically controllable and non-energized open construction. 
     
     
         4 . Electrohydraulic valve controller according to  claim 1 , wherein the hydraulic valve has a significantly more quickly switching construction than the additional hydraulic valve.