Research on the dynamic characteristics of seawater hydraulic cartridge-type 4/3 directional valve

Water hydraulic directional valve is a key control element in seawater fluid power system. Because of the properties of high bulk modulus and low viscosity of seawater, the leakage and dynamic characteristics of directional valve would be different from those of the traditional one. In this study, a new working principle of seawater hydraulic 4-3 cartridge directional valve (abbr. SHCDV) is introduced, and the mathematical model and simulation model of the SHCDV are developed in this paper. The pressure and flow characteristics are investigated through simulation and experiment. The optimal structure parameters and dynamic characteristic curves of SHCDV are achieved through simulation. The simulation results show that the control chamber area, the damping hole diameter of the cartridge valve, and the flow rate of the pilot valve have important influences on the dynamic characteristics of SHCDV. Meanwhile, the static and dynamic characteristics of SHCDV are measured using a water hydraulic-component-performance test stand. The results show that its rated pressure is 14 MPa, the flow rate is 120 L/min, the dynamic opening response time is 109 ms, and the closing time is 128 ms. The experimental results are basically consistent with the simulation results, and verify the accuracy of the simulation model. This research will lay the foundation for the further development of a high-pressure, high-flow, and fast-response SHCDV, and it can be widely used in oceanic exploration, marine development, desalination, and other fields.