Abstract:In the load-sensing (LS) hydraulic system, the LS feedback loop needs to return oil to tank and unload in the neutral position of the multi-way valve, for avoiding the pressure increase caused by oil trapped in the LS circuit. The working mechanisms and characteristics of the LS unloading loop for four different load-sensing multi-way valves in the neutral position were analyzed. The crane hoisting system was taken as the experimental subject. The flow and pressure characteristics of the load-sensing multi-way valve and system with LS feedback oil unloaded in the form of a fixed orifice were theoretically analyzed, simulation and experimental verification was performed.