ELECTROHYDRAULIC VALVE CONTROLLER
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.