Stiff Valve (Increased Torque)
In this graph the torque required to keep the valve moving has increased. At the point at which the valve starts to move, the black curve drops below the red curve. This is because the actuator has an increased load and is not moving as quickly as in the previous test. Therefore, the rate of change of volume in the cylinder is decreased and the pressure drops more quickly.
The SVM system can monitor this over time, document degrading performance, and assist in predicting when the valve should be serviced.