Modelling and experimental validation of a nonlinear proportional solenoid pressure control valve

Abstract

This paper investigates the static and dynamic behaviour of a pressure control valve with nonlinear negative characteristics. The pressure control valve has both reducing and relieving capability and is actuated by a solenoid. The static characteristics have been measured over the entire working range, covering the dynamic response of the solenoid, as well as the complete valve. A model is proposed that considers the flow as a mix of laminar and turbulent flow and flow forces with a flow angle that varies with the stroke of the spool. The model shows good agreement with measurements. The investigations show that the flow forces decrease with higher flow rates as a result of a flow angle that tends to go towards a vertical angle. This results in an increase in pressure with flow during pressure reducing mode. A linear analysis is also presented, explaining this as a negative spring constant in the low frequency range. Stability is, however, maintained.