Steady-state performance investigation of closed-circuit hydrostatic drive using variable displacement pump and variable displacement motor

This article investigates the steady-state performance of a closed-circuit hydrostatic (HST) drive using a variable displacement pump and a variable displacement motor where the speed of the drive is varied by controlling pump or motor. The drive is operated over a wide range of load torque and speed in two modes of operation: the pump controlled mode and the motor controlled mode. The efficiencies of the pump, motor, and the prime mover driving the pump are taken into account to analyze the overall performance of the drive. In this respect, considering various flow and torque losses of the HST drive components, the equations representing efficiencies of the drive are identified by comparing with the experimental data. The simulation is carried out using MATLAB. The results of the study may be useful to identify the control parameters of the drive to operate it at a reasonable efficiency zone.