A relief valve has been used to protect the hydraulic system from the inadmissible high pressure peak and maintain the constant system pressure against the change of flowrate. It must be satisfied with the three predominant demands, that are little pressure override, little pressure oscillation and noise, and fast response against sudden change of flowrate.
In this thesis, a nonlinear model of an electro-magnetic relief valve using flapper-nozzle valve formulate in explicit form from the fundamental principles of the rigid body motion and fluid dynamics. Model parameters, such as spring constant, electro-magnetic constant, and discharge coefficient, are identified form steady-state characteristics and physical dimensions of the valve.
And static characteristics of electro-magnetic relief valve, pressure override, compare with that of the other relief valve.