The Study On Shift Schedule Of The Automatic Transmission

Automatic transmission was born with the fast development of electronic technology. It has greatly improved the ease of using motor vehicles, so it can help drivers reduce fatigue during long-distance driving. In further, it also meet the requirements of people on using motor vehicles.Compared with the MT(manual transmission) and AT(Automatic Transmission), an AMT(Automated Mechanical Transmission) can be compact and affordable, provide the good fuel economy, and it also provide the effortless shifting of an AT. For the reasons above, AMT is receiving a great deal of attention, when fuel efficiency standards on vehicles are becoming more and more increasingly strict. Some have been installed by European vehicle manufacturer on their sports cars.Shift schedule is one of AMT's Key technologies. This paper has done some research on establishment methods of shift schedule, and analyses the influence factors of power and fuel-economy for the auto.First, the advantages, disadvantages and development prospects of various transmissions are analyzed according to the classification of automotive transmission. The development process, characteristics, system configuration of these transmissions are also introduced.An advanced shift schedule based on the optimized dynamic 3-parameter shift schedule, which makes maximum use of the power-train potential and meets well with the optimal driving conditions of the vehicles, is developed in this paper. Twomethods to calculate the shift schedule are introduced--one of which is of graphic,and the other, of analytic. For the latter, the mathematical model of shift is very accurate and convenient of use with computer, by which the shift schedule for optimal dynamic performance and fuel economy has been established practically.As the computer simulation can save a lot of manpower and material resources comparing with the true-car test, so in this thesis, the author uses the simulation toolbox Matlab/Simulink to set up the simulation model for shift schedules. The operating principle and implementation of each block under the model were introduced too. Using this model, the optimal-power shift schedule and optimal fuel-economy shift schedule above are simulated and proved to be reasonable.