Study On The Shift Schedule Of Automatic Mechanical Transmission

The automatic mechanical transmission (i.e. AMT) makes the transformation in the foundation of mechanical transmission, adding the self-shifting operation part. It is a new kind of automatic transmission, has received the advantage of hydraulic automatic transmission on convenient operation, and simultaneously has the performance of mechanical transmission:high efficiency, the low cost, easy to make, operation reliable and so on.At present the research on shift schedule on conventional car automatic mechanical transmission is already mature, coming up with the double parameter shift schedule, the dynamic three parameters shift schedule and the best synchronization shift schedule. At the present stage, AMT always uses the double parameter shift schedule, namely the throttle percentage and the vehicle speed as shifting control variable. Working on Hybrid Electric Vehicle (i.e. HEV) is mature day after day, but the research key point is the almost the vehicle control policy, namely the distribution of engine and electrical machinery's torque, rarely directing at the HEV shift schedule research, so almost the HEV uses the double parameter shift schedule. However, HEV has the wide difference in the system structure and the operation principle with the traditional automobile, cannot solely control by the double parameter to shift. In hill climbing or acceleration operating mode, operate by electrical machine and engine compound; in the retarding brake operating mode, generate electricity by the electrical machine to recycling brake energy. Therefore, study on HEV shift schedule probably considers the battery and electrical machine's influence. At the same time, the function of electrical machine changes along with the working mode, therefore under the different working mode, shift schedule should be different.The paper depends on the cooperative project with China Automotive Engineering Research Institute. Firstly, introduce the application of HEV and HEV AMT, simultaneously elaborated the research background and the significance of HEV AMT shift schedule.Through the research on shift schedule of traditional automobile AMT, obtain double-parameter-controlled shift schedule of the single axle type parallel HEV. In the research foundation of traditional automobile shift schedule, proposed the three-parameter shift schedule controlled by the engine torque, the motor torque and the vehicle speed according to HEV dynamic system characteristic, obtain the best dynamic property and the best economical efficiency three-parameter upward shift schedule, and aiming at HEV dynamic system characteristic, specially put forward the best economical efficiency three-parameter downward shift schedule under the brake mode.Using the shift schedules carry on the simulation in the advisor software, analyze and compare the result of the double-parameter and three-parameter shift schedules of the single-axle parallel HEV, protrude the superiority of three-parameter shift schedule.