Experimental investigation of a switched inertance hydraulic system

This article reports on experimental investigations of a switched inertance hydraulic system (SIHS), which is designed to control the flow and pressure of a hydraulic supply. The switched system basically consists of a switching element, an inductance and a capacitance. Two basic modes, a flow booster and a pressure booster, can be configured in a three-port SIHS. It is capable of boosting the pressure or flow with a corresponding drop in flow or pressure respectively. This technique makes use of the inherent reactive behaviour of hydraulic components. A high-speed rotary valve is used to provide sufficient switching frequencies and minimise the pressure and flow loss at the valve orifice, and a small diameter tube is used to provide an inductive effect. In this article, a flow booster is introduced as the typical switched system for investigation. The measured steady state and dynamic characteristics of the rotary valve are presented, and the dynamics characteristics of the flow booster are investigated in terms of pressure loss, flow loss and system efficiency. The speed of sound is measured by analysis of the measured dynamic pressures in the inertance tube. A detailed analytical model of a SIHS is applied to analyse the experimental results. Experimental results on a flow booster rig show a very promising performance for the SIHS.