Research of pressure limiting valve in the ESP under control of high-frequency PWM

In the ESP (Electronic Stability Program), the pressure limiting valve is used to control the max pressure in the brake system. Although the traditional relief valve can meet this requirement, the max pressure that can control is a certain value which can´t change due to the circumstance of the vehicle. In this paper, the high speed on/off valve under control of high-frequency PWM (Pulse Width Modulation) is used to control the max pressure in the brake system by changing the duty cycle of PWM. Nevertheless, this paper establish a high-speed on/off valve simulation model which is under control of PWM of 2k ~ 4k Hz modulation frequency in MATLAB-Simulink, and analysis the function of pressure limiting valve in different duty cycle of the control of PWM. Through this research, the application of the high-speed on/off valve is extended, and it is helpful to control the brake pressure precisely.