Four-port Hydraulic Transformer with Inlet and Outlet Equal Flow and Its Efficiency Characteristics

Abstract

In order to avoid throttling loss and recover differential pressure energy, braking energy and gravitational potential energy without changing the original hydraulic system, the four-port hydraulic transformer (FHT) is proposed. Its theoretical and experimental efficiency characteristics are researched. The basic structure and principle of the FHT are explained. Besides, the mathematical model of its efficiency is established. The results show that the pressure ratio can be changed by adjusting the control angle of valve plate, and the efficiency characteristics of the FHT match the efficiency characteristics of the hydraulic pump/motor. The total efficiency increases first and decreases afterwards with the increment of cylinder speed, and increases with the control angle of valve plate, while decreases with the recycling pressure difference.