Electronically controlled air suspension and rubber suspension represent the development direction of automobile suspension system at present. The development of automobile suspension in Europe and the United States has experienced the process of "leaf spring → air bag compound suspension → passive all-air suspension - active all-air suspension (i.e. ECAS system) or rubber suspension". In Europe and the United States, the price of rubber suspension and air suspension is not much different, but the use of different environments, air suspension can not be overloaded, so it is widely used in traction vehicles; Rubber suspension has strong adaptability and can be used in overload environment, so it is mainly used in off-highway vehicles or cars with harsh working conditions and large load requirements. At present, ECAS system has been applied in some buses in Europe, and it is expected that with the development of vehicle control technology, ECAS air suspension system will become a development direction of automobile suspension.

Although air suspension and rubber suspension have been introduced in the field of heavy trucks in China for many years, why has it not been mass-produced yet? The author believes that there are mainly the following reasons:

First, the development of heavy truck industry needs. With the development of China's high-grade highway, the increase of transportation volume, the popularity of the weight charging policy and the increase of the income of heavy truck users, they began to put forward higher requirements for the handling stability, ride comfort, comfort and safety of the vehicle, so the new suspension that meets the above requirements began to attract more and more users' attention.

Second, policy encouragement. Because air suspension and rubber suspension have the characteristics of light weight and low damage to the road, the national issued "road vehicle profile size, axle load and mass limits" (GB1589-2004), the provisions of the axle load mass limits of vehicles equipped with air suspension or rubber suspension, compared with the axle load mass of vehicles equipped with plate spring suspension by 15%. Therefore, at the policy level, the state has also made a tilt to the new suspension.