Design And Research On Electronically Controlled Air Suspension System

Air suspension use air spring as spring element, make use of the condensability of the air to achieve the function, it can improve cars'economical efficiency, directional ability of vehicle handing reliability,safety.Furthermore, it can release the strike to protect roads . Now, air suspension is used on both trucks and carriages widely abroad. And it's using on light trucks increases rapidly, a part of cars else begin to install air suspension gradually. The economy of our country has leapt forward in recent years, following the improved of roads'condition and paying more attention to the limits of overload by our country the implication of air suspension will be more and more widely, it is the tend that the traditional spring suspension system will be replaced by airsuspension system .In recent years,the electronically controlled air suspension of lifting axle become new a tend of technic development. The use of lifting axle of ECAS, make the lifting axle keep uprising to save fuel, reduce the wear of types, when there is no load, otherwise, put down the lifting axle to make equitable distribution of load. By the course of driving help ,the lifting axle is hung up, increase the load of drive axle to increase the force of drive effectively. For lifting axle can increase the performance of the vehicle effectively ,it become the most important part of air suspension systems.Based on the background above, this paper analyses the key parts in the design course of lifting axle by practical application, and give a careful descriptions of difficult points .the main views of the paper are : 1. The research of ECAS system and the piecing work 2. The research of air bellow and the piecing work 3. Design special tests for air suspension and the analysis of the test results (1).The research of ECAS and the piecing work ECAS is a control system that by the way of the electronics to control air suspension systems to achieve many functions . The main parts including : the module of electronic control(ECU),solenoid valve,attitude sensor,air spring remote controller 。The control of ECAS is to carry out the whole control by ECU, attitude sensor translate the changes of attitude to be electronic signals ,then transfer it to ECU,ECU receives signals transferred by all the sensors(including attitude sensor and pressure sensor ),the send dictates to solenoid valve ,then it control the air's input and output course of the air suspension .on a 6X2 vehicle equipped air suspension which is controlled by ECU , in the mode of driven help ,when the load of driven axle reach it's rated load , float axle begin to take off the extra loads—lifting axles increase its load with driven axles having no changes . When lifting axles reach its rated load ,the float axles and driven axles increase together by a ratio----this is also the pressure ratio of float axle and driven axle set in advance----until it reach the max permit load of the vehicle . This kind of load distribution method make the vehicle get enough driven force when it is on the roads which is slippery or have less surface attachment coefficient , and it can also reduce the types'wear of both float axle and driven axles at the time vehicle get steering . The vehicles need more driven force when they move on a slope (grade climbing) When vehicles run at a low speed you can turn on the switch to use the driven help . Release the load of float axle and increase the load of driven axle at the same time to get suitable driven force,but this method is not benefit for distribution of the brake force , and when compared with equality pressure control ,it need parts and systems more complex . How to optimize the parameters is the key and difficulty in the fit course of ECAS this paper induces the basic definition ,main consist parts basic functions the principle and method of the control system . The paper also induces the parameters of the optimize control function of the final...