Study On Energy Management Strategy For AMT Medium Hybrid Electric Vehicle Based On Efficiency Optimized

Automatic Manual Transmission not only has the function of automatictransmission，but also has some advantage like manual transmission, such as hightransmission efficiency easy to manufacture. The medium HEV equipped with AMT isa Single-axis Parallel hybrid electric vehicle. Compared with mild HEV, The proportionof ISG motor power in the powertrain has increased. The vehicle could be driven by themotor independently when the clutch is disengaged which increases the utilization ofmotor and this can decrease the fuel consumption and gas exhaust. The regeneratingenergy recycling rate is increased when the vehicle is braking, so, more kinetic energyis converted into electric energy of battery by the ISG motor. Further, working point ofthe engine and ISG motor can be optimized by controlling the gears of AMT in thedriving condition. And the regenerating energy recycling rate can be also increased,because the working point of ISG motor can also be optimized by the AMT in thebraking condition. Then, medium HEV with AMT become an important researchingbranch.In this dissertation, based on a medium HEV with AMT, the energy managementstrategy is studied with improving the fuel economy as objective. The main researchesare as followed:①Based on the experiment on the engine and motor, the fuel consumption modeand efficiency mode of engine and efficiency mode of motor are built. And thenthe internal resistance model and efficiency model of the battery are built after sometheoretical derivation of the battery charging and discharging experimental data. At last,the efficiency mode of the AMT transmission is gained based on the theoreticalanalysising of power loss.②Based on efficiency model of the key components and the kinetic equation ofthe power transmission, the theoretical calculating formula of system efficiency forvehicle under different working modes are derived. After building the optimal model ofsystem efficiency under different working modes, the target gears of AMT and theobjective torque of motor are worked out with maximizing systematic efficiency asobjective, by comprehensively considering the efficiency of the engine, motor/generator,battery and transmission system. At the same time, the objective gears of AMT isoptimized to improve energy recovery under regenerative braking modes. ③The working mode switch strategy and torque distributing strategy areproposed based on the static results of medium HEV with AMT by system efficiencyoptimizing. At the same time, the economic shift rules of the vehicle are gained.④Backward simulation model of medium HEV with AMT is built based onforward modeling idea. Then, the simulation of the proposed energy managementstrategy is carried out, and comparative analysis are taken with the traditional electricassist control strategy under some driving cycle condition.