In foreign trade export, ECAS is an electronically controlled air suspension system for passenger cars. It's an export product. ? The bus electronically controlled air suspension system (ECAS) is composed of ECAS electronic control unit, solenoid valve, height sensor, air bag and other components. The height regulator is responsible for detecting the change of the height of the vehicle, the electronic control unit will accept the input information, judge the current state of the vehicle, stimulate the solenoid valve work, several solenoid valves to achieve the charging and discharging of each air bag adjustment. With the improvement of people's requirements for vehicle riding comfort and the development of bus suspension technology in China, the application of air suspension in buses is becoming more and more extensive.