Patent ID: 8683793
Filing Date: 2014-04-01
Classification: E02F,F15B

Abstract:
1. A method for recuperating potential energy during a lowering operation of a load, wherein a hydraulic system is adapted to lift and lower the load, the hydraulic system comprising a hydraulic actuator comprising a hydraulic cylinder which comprises a piston rod, a piston side and a piston-rod side, and a hydraulic machine which functions as both pump and motor, comprising providing at least two energy recuperation modes, a first mode enabling fluid communication between the piston-rod side and the piston side in the hydraulic cylinder and enabling fluid communication between the piston side and the hydraulic machine, a second mode preventing fluid communication between the piston-rod side and the piston side in the hydraulic cylinder and enabling fluid communication between the piston side and the hydraulic machine, determining, for a current operating state representative of at least a desired actuator speed at a given load acting on the piston rod, an amount of energy that can be recuperated for each one of the modes, selecting, with respect to constraints of the hydraulic system used with regard to at least a maximum system pressure, one of the modes in response to the current operating state, and controlling the hydraulic system according to the selected mode.