The Research On Shift Control Of AMT For Hybrid Electric Vehicle

With the constantly improve of the modernization level, the automobile output is rising,the proportion of automobile exhaust in atmospheric pollution is becoming higher and higher.People are turning their eyes from performance problems to new energy and environmentalprotection technologies of the car. Hybrid electric vehicle has the advantages of energysaving and low emission, the strengths of high energy and high specific power, so it hasbroad market prospects.The running condition of bus is complicated, the frequent of shifting is higher, thedriving strength is greater, and it makes the driver work in heavy task. Automatictransmission can change gears automatically according to road conditions, and reducing thelevel of the driver’s fatigue. It is the ideal choice for hybrid electric vehicle. Compared withother several kinds of automatic transmission, AMT has the advantages of simple structure,high transmission efficiency. It is widely used in the vehicle. But it will interrupt the powerwhen shift and cause shift impact. This would require to develop control strategy. Throughcoordinated control of engine, motor, clutch, transmission to reduce power interruption time,reduce the shift shock and then improve the shift quality.This paper base on a single axial parallel hybrid electric vehicle as the research platform,carry out the study of shift control during shift process. The main contents are as follows:(1) Give an introduction of the whole vehicle structure of single axial parallel hybridelectric vehicle. Introduce the definition of shift quality and the shift evaluation index.Introduce shift process with clutch operating, put forward the shift ideal of without clutchoperation and analyze the feasibility and significance without clutch operation from the onworking principle of the AMT.(2) Build the single axial parallel hybrid vehicle powertrain dynamics model. Analyzethe dynamics relationship of shifting process. Develop a shift control strategy without clutchoperation and analyze every stages of shift process. Torque coordinated control of engine, motor can be realized by controlling the throttle opening and motor torque. For activesynchronous of motor adopt fuzzy PI control method. On the basis of the two parameter shiftschedule, decision-making shift was designed, and then analyses the automatic shift controllogic, shifting logic model is established.(3) Build the models of different modules.The engine use method of experiment; themotor through voltage equations and torque equation and kinematics model to build motormodel. The transmission and actuator module, use the transfer function module to build theshifting motor.(4) Make offline simulation for no clutch operating in parallel hybrid electric vehicle,use the corresponding evaluation index of shift quality to evaluate the simulation results.Make offline simulation for clutch operating,and compare the result with no clutch operating.After the offline simulation, build MotoTron hardware in loop test platform, and makesimulation test for with clutch operation and without clutch operation,analyze and comparethe result, verify the effectiveness of the shift control strategy and the correctness ofsimulation model.