Experimental and Numerical Investigation of Motion-Induced Fluid Force for a High-Speed Valve

Abstract

A high-speed valve (HSV) is used to control the friction plate accurately and flexibly in the shifting stages of an automatic transmission. In the past, the transient modeling and dynamic improvement of HSVs neglected fluid–solid coupling and motion-induced fluid force (MIFF), which made it difficult to improve the response performance and kinetic energy efficiency of HSVs. In order to fully represent the MIFF and internal flow field features, a novel general approximate model for HSVs with a more accurate fidelity unsteady computational fluid dynamics (CFD) analysis is built in this paper. In addition, the experimental data of HSVs when the sphere is moving in oil-free or oil-immersed media are collected to verify the proposed model. In order to validate the model, the mechanism law of buffer groove towards the MIFF is tracked at length. The motion-induced added mass with buffer groove is reduced by 43.9%. The experimental results show that under the working pressure of 1 MPa (rated pressure), the opening time is shortened to 0.90 ms, which is 11.8% shorter than the original structure. The closing time is shortened from 1.5 ms to 1.34 ms, which represents a decrease of 10.7%. The buffer groove improves the kinetic energy efficiency from 41.91% to 46.70% in the start-up phase and from 41.98% to 56.75% in the close-up phase. This study provides a new perspective for improving the dynamic performance and energy efficiency of the system in terms of the MIFF.