Flow-Induced Deviation Mechanism and Structural Optimization of Engine Valves Under Braking Conditions

Abstract

Under braking conditions, the valve is prone to lateral swing, which significantly compromises engine performance and longevity. Research indicates that the asymmetric vortex structures around the valve are one of the primary factors inducing effects such as lateral swing. Therefore, addressing this issue, this paper proposes three structural optimization strategies for controlling the flow around the valve: modifying the valve’s camber radius, altering the exhaust port structure that the valve cooperates with, and applying tripwires to the valve. The control effects of these three strategies are demonstrated through three-dimensional numerical simulation techniques, and the control mechanisms are elucidated through vortex field structure analysis. The results reveal that the tripwires improve the asymmetry of the flow field around the valve by disrupting vortex formation at its inception. These analytical results provide specific solutions for reducing the lateral force that induces valve deviation under braking conditions, which possesses important engineering significance.