Investigation of the Dynamic Characteristics of a Two-Stage High-Speed On/Off Valve with Adjustable Maximum Opening

The effective way to improve the reliability of the fuel metering system in an aero-engine is to use a high-speed on/off valve (HSV) instead of a servo valve as the pilot stage of the fuel metering valve. However, the dynamic performance of the fuel metering valve is easily affected by the HSV, so a novel two-stage high-speed on/off valve with adjustable maximum opening (AMOHSV) is proposed in which the maximum stroke of the main valve is regulated with an adjustable rod. Firstly, the structure and working principle of the proposed valve are presented. Then, an entire mathematical model is established and verified based on a multi-physical field coupling mechanism. Finally, simulations and experiments prove that when the maximum opening is 0.2 mm, the total opening time and total closing time of the AMOHSV are within 5 ms. In addition, an upward inflection point and a downward inflection point on the pressure curve of the control chamber can be used to identify the total opening time and total closing time, respectively. The research results also prove that the proposed structure solves the conflict between the maximum flow rate and the dynamic performance of the traditional HSV.