Abstract: Solenoid valves are mainly used as inlet and outlet valves in vehicle's anti-block system (ABS). The inlet valve is used to control the pressure increase ramp in the pressure-increase phase of the ABS. When the valve is in linear control mode, the control accuracy and dynamic response are poor. So a new stepped control method based on switch control is proposed, and the conditions that are suitable for stepped control are given. The key matching parameters are determined based on the characteristics of the response of solenoid valve under switch control mode. A test bench is built with a real vehicle brake system. The values of the key parameters are adjusted to meet the requirement of the stepped control. Then these adjusted parameters are used in an ABS algorithm on road test. Results show that the proposed method can quickly determine the reasonable ranges of the key parameters and the control accuracy is high.

Key words: vehicle engineering, anti-block system(ABS), stepped control, step threshold, orifice, response time