Opening and closing of a novel high-speed switching valve

The current paper presents a high-speed switching valve for the piston motion control of a single-piston hydraulic free-piston engine. A performance prediction model is developed and a test method for the valve spool movement without using displacement sensors is provided. The agreement between experiments and simulations indicates that the model can predict the valve performance. The valve response is rapid enough for the piston motion control of the engine. The flow capacity of the valve is not reduced by the fast response requirement. The time between the step of the control signal and the response of the pilot valve is important for reducing the valve response lag. A smaller gap is helpful in improving the valve response.