Research And Simulation On Shift Schedule Of Automatic Mechanical Transmission

With the development of society economy and the increase of the automobile possession, the market demand for automobiles equipped with automatic transmission is increasing with the day and the application of automatic transmission is on the growing popularity. Although now the city-buses used the traditional manual transmission are able to meet the basic requirements of the dynamic performance and fuel economy, there are some problems such as hard working on shifting, be hard to master the best opportunity of gear shifting, uncomfortable travelling and unsmooth driving. AMT (Automatic Mechanical Transmission) is a type of high and new technology products that adept to the situation of china nowadays and the most suitable of applying in the city buses and trucks because of its outstanding advantages of high efficiency, low cost and simple structure. And it has a wide development prospects.This thesis based on the actual project, primarily studies on shift schedules for the automatic mechanical transmission (AMT) of the series of B90V6110J city-bus, in order to improve the power and fuel-economy of the vehicle. The shift schedule is the soul of the AMT which affects the optimal-power and fuel-economy directly. The author chooses the shift schedule as the key technology problem to be researched and the main study aim of this thesis is to get the optional shift schedules for the AMT and so improve the power and fuel-economy of the vehicle.By analyzing auto dynamics, fuel economy and engine characteristics, building vehicle running equation and fuel consumption equation, the methods for establishing optimized power and optimized fuel economy shift schedule are both primary studied. The author draws up the best performance shift schedule of the city-bus. In this paper, the optional-economical and the optional-power schedule for the shifting gear of the AMT automobiles is analyzed and researched. Considering the economy and power of automobiles, a synthetically shift schedule is further researched. In view of the large quality change during the operation of city buses and the change influencing the shift schedule, this thesis propose variable quality shift scheme as an innovative point, enriching the control theory of the automatic shifting gear of AMT vehicles.Because the computer simulation can save a lot of manpower and material resources comparing with the true-vehicle test, so in this thesis, the author uses the simulation toolbox MATLAB/Simulink to set up the simulation model of engine and drive-train as well as a simulation-based shift schedule evaluation model. Using this model, the optional economical, the optional power and the synthetically shift schedule above are simulated and proved the synthetically shift schedule to be reasonable. Through comparing the simulation results of variable quality shift schedule and the synthetically shift schedule, demonstrate the variable quality shift scheme is excellent.