Application Research Of Automated Mechanical Transmission In Medium-sized Off-road Vehicle

Automated Mechanical Transmission, as so called AMT, is a new-style transmission system. AMT technology applies the automatic technology to the manual mechanical transmission and makes the selection-gear, shift, clutch and throttle implement automatically. Therefore, research and development of AMT suitable for Off-road vehicle not only fits the situation of our country, but also can realize automatization-alteration and improve battle effectiveness of the Off-road vehicle.Shift schedules decide the time to shift and are the soul of the AMT. When the AMT is working, by comparing the states of the vehicle with the optimal shift schedules, the AMT decides the optimal shift time and achieves the shift automatically. This will lessen the tiredness of the driver and improve the safety. At the same time, the power and fuel-economy of the vehicle can also be improved. The author chooses the optimized dynamic 3-parameter shift schedule to apply in the Off-road vehicle equipped with AMT and the main study aim of this thesis is to improve the power, trafficability, and fuel-economy of the vehicle.The control parameter of shift schedule can be divided into single-parameter, 2-parameters and 3-parameters. According to the shift mode, shift schedule can be classified into off-road and flat shift schedule. The research of this thesis is focused on the 3-parameter dynamic shift schedule based on off-road and flat shift mode.Through making dynamics analysis in the off-road mode, established driving equation, and did some research on the methods making dynamic shift schedule in accordance with this formula, including graphic method and analytic method, and practically make optimal 3-parameter dynamic shift schedule surface; established fuel consumption equation of the flat mode, and did some research on the methods making fuel-economical shift schedule and improved methods; In order to solve the influence of mass on the shift schedule, the author presents a variable-structure-controlled shift system. This enriches the theory of shift schedules.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. The improved and unimproved dynamic and fuel-economical shift schedules in the two mode were used respectively in the processes of simulation-based evaluation, and do some comparisons. Using this model, the 3-parameter dynamic shift schedule based on off-road and flat shift mode are simulated and proved to be reasonable.