This paper deals with modelling and simulation of dynamic processes in hydraulic system with simultaneous operation of a directly operated pressure relief valve and a directly operated three-way pressure reducing valve. A comprehensive nonlinear mathematical model is deduced in order to predict the performance of the studied system. The proposed model takes into consideration most nonlinearities of the studied valves. A computer simulation, based on the proposed model, is performed to predict the transient performance of the system. The validity of the proposed model is assessed experimentally in the transient mode of operation. The results show significant agreement between simulation and experiments.
Dimitrov et al. (Sun,) studied this question.