Energy Efficiency of Three-Chamber Cylinder with Digital Valve System

Commonly used hydraulic cylinders have a piston and a piston rod. The piston divides the inside of the cylinder in two chambers and pressures which affect how the piston generates the linear motion. Use of distributed valve system enables several control modes in a system of this type because different control edges can be controlled independently. These control modes can be used for decreasing energy consumption and improving controllability. The traditional hydraulic cylinder has only a limited number of control modes, but by utilizing a multi-chamber cylinder the number of control modes can be increased. In this paper, a three-chamber cylinder is studied using measurements and simulations. The control of the cylinder is presented and measurements are done in a 1-DOF boom mock-up to show the operation of the system in practice. A simulation model is built to investigate further the energy saving capability of the system. The studies show that losses can be significantly reduced by replacing traditional cylinder drives with multi-chamber cylinders.