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High speed on-off valves (HSVs) are widely used in advanced hydraulic braking actuators, including regenerative braking systems and active safety systems, which take crucial part in improving the energy efficiency and safety performance of vehicles. As a component involving multiple physical fields, the HSV is affected by the interaction of the fields-fluid, electromagnetic, and mechanical. Since the opening of the HSV is small and the flow speed is high, cavitation and vortex are inevitably brought out so that increase the valve’s noise and instability. However, it is costly and complex to observe the flow status by visual fluid experiments. Hence, in this article a visual multi-physics system simulation model of the HSV is explored, in which the flow field model of the HSV built by computational fluid dynamic (CFD) is co-simulated with the model of hydraulic actuator established by AMESim.

A high speed on-off valve (HSV) under the control of high-frequency pulse width modulation (PWM) can make control as linear as proportional valve do, since its valve opening is adjusted linearly by the duty ratio within a certain effective range. It is essential for HSV to achieve linear control performance precisely. In practice the performance is influenced by not only the control strategy, but also by the structural parameters of the valve, such as the valve core diameter, the conical seat angle, and so on. In this article, it is indicated that the effects of the structural parameters on the linear control performance of HSV is exerted by flow force, because different structural parameters bring about different valve opening-flow force characteristics. Hence the relation between the valve structural parameters and the flow force is emphasized. First, the mathematical model of HSV is established, including the flow force mathematical formula being derived in detail.

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.