Active Speed Regulation Of AMT For Series-parallel Hybrid Electric Vehicle During Gear Shifting

With the increasing issues energy exhaustion and environmental contamination,a large amount of automakers and research institutions are reinforce their research on new energy vehicles and energy-efficient vehicles.Pure electric vehicles are limited by the range problem;fuel cell vehicles are constrained by the infrastructure;thanks to the good fuel economy,hybrid vehicles have become a better solution;Automatic mechanical transmission has a strong torque carrying capacity and simple structure,and its application in commercial hybrid vehicles can improve the efficiency of the engine,so it has a wide range of application prospects.However,because the automatic mechanical transmission is a non-power shift,and after the synchronizer synchronization process,it needs to control the clutch combination to restore the engine power smoothly,which will make an impact on vehicle’s dynamics and comfort.In order to settle aforementioned issues,this paper inquires into the shifting process of hybrid electric vehicles equipped with automatic mechanical transmissions,and does the following work.Firstly,the study model is positioned,the principal performance indexes of the car are determined,and the parameters of the major parts of the powertrain are matched by using the formula and the appropriate models are selected on the basis of the power requirements for the car.The hardware parts of the whole vehicle were modeled,for instance,engine model,transmission model,driving resistance model and motor model,to prepare for the simulation work afterwards.Secondly,the powertrain system is analyzed,the operating modes of the vehicle are classified and the specific usage and power flow direction of each operating mode are introduced;the working principle of gear shifting is explained with the example of shifting from first to second gear,and the shifting process is summarized;the kinematic and dynamical relationships between the parts of the driveline are analyzed in detail,and the first-order kinetic differential equations of the entire vehicle driveline are summarized.Thirdly,the control design of the power switching before the start of gearshift is carried out according to the control problem;the proportional-integral differential controller is designed for the input and output quantities of the input part of the gearbox and the controlled object.The transfer function is solved by the state space equation,and the reasonable adjustment of the controller parameters is completed.The controller plays the role of active speed regulation for the speed synchronization of the gearshift process.Finally,the simulation was verified on the simulation platform,and the shifting logic was developed according to the two-parameter shifting rule,and the two gears of first and second gears were selected for up/down simulation.