Patent ID: 8561397

Claim:
A hydraulic system, the hydraulic system, comprising: a hydraulically operated device which is supplied a hydraulic fluid that when is pressurized actuates the hydraulically operated device; a reservoir connected to the hydraulically operated device for supplying the hydraulic fluid to and from the hydraulically operated device; a first sensor measures a first volume of the hydraulic fluid in the reservoir; a second sensor, which is connected to the hydraulically operated device, measures a parameter of the hydraulically operated device which is indicative for a second volume of the hydraulic fluid; and a controller calculates the second volume of the hydraulic fluid based on the parameter and determines a leakage of hydraulic fluid in the hydraulic system based on the first volume and the second volume, wherein the controller compares the measured first volume with a predetermined reference value of the first volume, and wherein the reference value of the first volume is a function of the parameter.