AMT Design Of Hybrid Electric Vehicles

With the increasing of vehicle numbers in the world,energy shortage crisis and environmental pollution have become more and more serious.The new energy vehicles,such as hybrid electric vehicles,show good fuel economy and provide a new choice for reducing the dependence of traditional energy.Hybrid electric vehicle has two power sources to supply the traction motivation: the motor and the engine.Compared with traditional vehicle,hybrid electric vehicle can maximize the engine efficiency through the coordination between the engine and the motor.At the same time,with the great development of engine technologies,such as Atkinson cycle,cooling exhaust gas recirculation,low temperature combustion,and so on,the engine characteristic would be no doubt improved and enhanced: a better thermal efficiency and an expanding area of fuel economy.Furthermore,the development of engine technology would subsequently influence the powertrain architecture.The main contents of this paper are organized as follows:1.A review of the advanced technologies in the field of the engine is made and the characteristics of each technology and its influence on the combustion thermal efficiency is analyzed.Moreover,based on the existing technical conditions and the development of the engine technology,a future engine BSFC MAP with high thermal efficiency and better fuel economy is obtained.2.The influence of future high thermal efficiency engine on the powertrain architecture is studied in Chapter 2.With the aid of MATLAB software,the dynamic programming algorithm is applied to investigate the influence.And the simulation results show that the fuel consumption decreases greatly for the future high efficiency engine,compared with that for the conventional engine.Meanwhile,for the future high efficiency engine,the improvement of the gearbox with more gears on the fuel consumption decreases significantly.And four gears is the turning point of the fuel consumption trend where the degree of the decrease from two gears to four gears is more obvious and much bigger than that from the four gears to the six gears.3.According to the simulation results of dynamic programming,a new hybrid power coupling mechanism based on AMT is proposed,and the mechanism is introduced in detail in Chapter 3,including structure composition,working modes and shift processes.4.The simulation of this architecture,including the fuel consumption and gearshift quality,is carried out in AMESim software.Through the cooperation between the engine and the motor,this new architecture can fulfill the entire driving cycle with different working modes,such as EV mode,HEV mode and regenerating mode.And a good fuel consumption is achieved.In addition,the shift process in the EV mode and HEV mode is analyzed in detail,including the torque variation of the clutch,of the synchronizer and of the wheel,and the characteristics of the engine and the motor.The simulation results demonstrate that the shift process in the EV mode and HEV mode can be completed without power interruption and show good gearshift quality.