Electronic Variable Geometry Turbocharger (VGT) Control Valve
The electronic VGT control valve is a 4-way proportional hydraulic flow control valve with a closed center position. The valve controls the linear actuator position of a closed loop hydraulic servo by charging and venting the flow on both sides of a piston. Linear displacement feedback from the actuator varies a feedback spring force to move the valve spool to the center closed position when the actuator reaches the desired position. Therefore, the actuator position is dependent only on the control valve current, it is independent of the hydraulic fluid temperature and viscosity.