Flow and Pressure Control of Swash Plate Variable Displacement Pump with Load Sensing and Pressure Compensator: An Experimental Approach

A variable displacement pump (VDP) with load sensing and a pressure compensator is more efficient than a fixed displacement pump (FDP). In FDP, if the load increases, the excess flow passes through the pressure relief valve (PRV), whereas in VDP, the excess flow passes through the compensator. If the system load increases, the flow is reduced to a minimum by changing the swash angle, which increases the system’s efficiency. In the present study, the effect of different precompression settings of load sensing (LS) spring and delivery pressure sensing (DPS) on the flow and pressure is measured at a particular speed of the motor. At a constant speed of the axial piston pump, the variation of flow can be generated by activating the LS mode. Whereas the DPS pre-compression setting can control the maximum system pressure, the maximum 55 lpm flow at 56 bar pressure was observed at 1200 rpm, and full opening of the direction control valve (DCV) at no load condition. Whereas, the flow reduced to 31 lpm after activating the minimum LS pre-compression. Hence, in the LS mode of operation at constant speed and constant pressure, the variation of flow is obtained. At full load conditions, the flow reduces to the minimum flow for lubrication purposes only.