An exemplary controller includes a control valve that includes an electric actuator operatively coupled to a valve stem, a piston operatively coupled to one or more hydraulic fluid paths controlled by the control valve and including a piston shaft, a rotatable shaft operatively coupled to the piston shaft and mechanically isolated from the valve stem and capable of adjusting geometry of the variable geometry turbine, and an electronic sensor capable of sensing an angular position of the rotatable shaft. Various other exemplary systems, methods, devices, etc., are also disclosed.
1. A variable geometry turbine comprising:
a turbine housing having an inlet for exhaust gas and an outlet, a volute connected to the inlet and an outer nozzle wall adjacent the volute;
a center housing attached to the turbine housing and having a center bore carrying a bearing assembly;
a turbine wheel carried within the turbine housing and attached to a shaft extending through the center housing, the shaft supported by the bearing assembly;
a plurality of vanes having rotation posts extending from a first vane surface substantially parallel to the outer nozzle wall, the posts received in circumferentially spaced apertures in the outer nozzle wall, the vanes further having actuation tabs extending from a second surface of the vanes distal the first vane surface;
a unison ring intermediate the center housing and the vanes, the unison ring having a plurality of slots, the slots receiving the tabs, the unison ring further having an actuation receiver;
a crank shaft movable continuously from a first position to a second position, movement of the crank shaft imparting force to the actuation receiver to urge rotational motion of the unison ring, the rotational motion of the unison ring causing the tabs to move in the slots;
an oil control valve for moving the crank shaft from the first position to the second position wherein the oil control valve includes an electric actuator and a valve stem, the valve stem mechanically isolated from movement of the crank shaft; and
an electronic sensor for sensing movement of the crank shaft.
2. The variable geometry turbine of claim 1 , wherein the electric actuator actuates the valve stem based on a signal having a duty cycle and wherein a constant, non-zero duty cycle maintains the valve stem in a substantially steady position.
3. The variable geometry turbine of claim 1 , wherein the electronic sensor includes a resonator circuit.
4. The variable geometry turbine of claim 3 , wherein moving the crank shaft moves the resonator circuit.
5. The variable geometry turbine of claim 1 , wherein the electric actuator actuates the valve stem in response to a pulse width modulated signal.
6. The variable geometry turbine of claim 5 , wherein the pulse width modulate signal has a frequency in a range from approximately 80 Hz to approximately 150 Hz.
7. The variable geometry turbine of claim 5 , wherein the pulse width modulated signal reduces static friction of the valve stem.