Effects of design parameters on cavitation in a solenoid valve for an electric vehicle braking system and design optimization

Keeping pace with the current rapid development of clean energy, hybrid cars and electric vehicles are receiving extensive attention. In electronic control brake systems, which are essential to these vehicles, a solenoid valve is used to control the hydraulic pressure, which boosts the driver's braking force. However, strong cavitation occurs at the narrow gap between the ball and seat of a solenoid valve due to sudden decreases in pressure, leading to severe damage to the valve. In this study, we numerically investigate cavitation in a solenoid valve to discover geometric parameters that affect cavitation, and we develop an optimal design to minimize the cavitation using an optimization technique. As a result, we propose two design guides for the solenoid valve subject to cavitation: the ratio of the narrowest gap area to the inlet area and the narrow gap length. We also find that preventing a sudden reduction of a flow passage is important to reducing cavitation. Finally, using an evolutionary algorithm for optimization we minimize cavitation. The optimal design results in a maximum vapor volume fraction of 0.051, compared to 0.74 for the reference model.