Research On Shift Schedule Of Automotive Mechanical Transmission (amt)

Due to its advantages of simple structure, high transmission efficiency,low cost, good manufacturing succession, etc.,Automated Mechanical Transmission (AMT) holds an important place in the automatic transmission family, Vehicles can automatically gearshift with the help of automatic transmission, which can reduce driving fatigue, improve vehicle dynamic quality, fuel economy and reducing emission also.Automatic mechanical transmission AMT)is a type of high and new technology products that adepts to the situation of China nowadays.And it has a wide development prospects.Automated Mechanical Transmission (AMT) is rebuilded with the traditional dry clutch and manual gear transmission, The major change is the manipulation of the manual transmission, which is that using the electronic control to achieve automatic transmission without changing in MT. The input signal of the control unit of AMT(ECU) are the ideas of driver (the location of accelerator pedal and the choose of shift) and the working state of vehicle(including the rotate speed of engine,the state of throttle,the speed of vehicle and so on).ECU generated output signal with the shift schedule, control schedule of clutch, Adaptive adjustment of the engine throttle, The control process simulate basically in the working of Throttle, the clutch and shift in the start and shift, which is cooperated well.About the vehicle of the AMT, the shift schedule is the core of the control system which effect the optimal-power and fuel-economy directly. In the using, by the contrast of collected running state and the shift schedule, the car can got whether the speed reach the best shift speed, and shift by itself. So it can relax the driver, improve the safety, and got good optimal-power and fuel-economy.Vehicle usually runs under the non-stable conditions of acceleration or deceleration, therefore, to get satisfactory 3-parameters shift schedule, a match between engine and transmission must be taken into account and a precise description for engine dynamic torque and fuel consumption characteristics is required.In this paper, engine stable test data of Santana 2000 sedan were revised and fitted to build dynamic torque and fuel consumption models.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 dynamic three-parameter-controlled optimized power shift schedule is designed on the basis of test data, adopting improved analytical methods, considering the effect of road grade.In view of the effect of vehicle mass to shift schedule, a readjustment plan is proposed and applied to design the optimized fuel economy shift schedule.So the problems brought by vehicle mass are resolved.For the purpose of shift schedule evaluation, simulation models of engine and drive-train, as well as a simulation-based shift schedule evaluation model were established using Matlab/Simulink. The gear-shifting processes were simulated on the basis of the drive-train related parameters of Santana 2000 sedan, and the improved and unimproved dynamic and fuel-economical shift schedules were used respectively in the processes of simulation-based evaluation. The conclusions are summarized as follows:gear-shifting repetition on slope and changes of jerk are greatly decreased by the improved optimal dynamic 3-parameter shift schedule; and the computation complexities as well as fuel consumption are reduced by the improved optimal fuel-economical 3-parameter shift schedule.