Controlling Variable Displacement Hydraulic Pumps for Energy Conservation

The possible causes of hydraulic power losses in both closed and open loop hydraulic systems are discussed. The means of minimizing these losses with the proper choice of closed versus open loop systems and with maximum utilization of variable displacement pump controllability are discussed. Also discussed are means of reducing prime mover size with pump power limiting controls to increase power generation efficiency. Examples are analyzed to illustrate the energy saving potential of closed loop pressure control, open loop pressure and flow compensation, and closed or open loop pump power limiters.