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The performance of Hydraulic Anti-lock Braking System (ABS) is important to vehicle brake safety. In this paper, finite element models and simulation models for studying dynamic response of solenoid valve, a critical part of ABS, are established. Based on the calculation results, which are proved in experiment, several effective methods for improving the performance of the solenoid valve are presented. Furthermore, an ABS-vehicle model is developed to study the influence of hydraulic ABS parameters on braking effect. The simulation results have good agreement with the data of in-vehicle driving experiments.

High speed on-off valve is applied widely in vehicle control systems. When high speed on-off valve is controlled by Pulse Width Modulation (PWM) of high frequency, the valve core can float at a certain position which is adjusted by changing the duty ratio within a certain effective range. Then the high speed on-off valve can control the flow and pressure linearly like proportional valve. Thus it is essential to extend the effective range of duty ratio to improve the linear control performance of high speed on-off valve. In this paper, the high speed on-off valve of the automotive Electronic Stability Program (ESP) is the focus, and its flow force is analyzed in detail to get the effects of hydraulic parameters on the valve performance. The mathematic model of the high speed on-off valve is derived. Then the valve structural parameters are optimized according to the Genetic Algorithm(GA), offering the theoretical references for extending the effective duty ratio of PWM.