AMT Shifting Control Strategy And Mechanism Optimization Of Three Axis Plug-in Hybrid Light Commercial Vehicle

The car has brought convenience to people’s lives,but also brought environmental problems and energy issues,these two issues directly affect the development of China’s automobile industry.Compared with conventional vehicles,electric vehicles have many advantages: zero pollution,low noise and high efficiency.The development of electric vehicles and new energy vehicles is an effective way to solve environmental pollution and energy shortage.The purpose of this paper is to control and optimize the two-speed AMT system of the pure electric mode of the hybrid electric vehicle with a three-axis plug-in hybrid electric vehicle.With the continuous development of science and technology,people’s requirements for the AMT system are getting higher and higher.On the basis of automation,more emphasis on intelligence,according to different driving intentions,the design of a reasonable shift schedule,improve the overall dynamic and economic performance of the car.Reasonable shift schedule can avoid the driver due to improper operation of the shift caused by traffic safety problems,improve ride comfort and ride safety.In order to meet the requirements of the driver’s power,the optimal power shift schedule is designed.In order to improve the efficiency of energy utilization,this paper designs the best economic shift schedule.In order to solve the problem that the AMT position is not accurate and the gear shift is slow,a new gear shifting mechanism is designed,and the online correction strategy of AMT gear position is developed.To sum up,this paper has carried on the control and the optimization of the AMT system from the two aspects of the shift schedule and the shift mechanism:According to the parameters of the three axis vehicle,the Truck Sim vehicle model isbuilt.According to the experimental data of motor,the torque characteristics of the motor and the efficiency of the motor are analyzed.According to the two speed AMT structure parameters,built two speed AMT model.The formulation of the three axis vehicle electric mode two-speed AMT optimal power and shifting mechanism rules,analyzes the different shift modes,according to the two-speed AMT,using mapping can establish speed-accelerator pedal opening two parameter shift schedule based on degree,according to the road traffic,the driver on the power and the economy of different requirements,and the two parameter shift schedule is further divided into the optimal power shift schedule to the principle of the maximum acceleration and the best economic shift schedule of motor efficiency optimization.A comprehensive shift schedule based on driving intention is developed.Driving intentions include: driving style,acceleration intention,braking intention.For different driving style,divided into dynamic driving style and economic driving style;according to different acceleration intention and braking intention,The acceleration intention is divided into emergency acceleration,general acceleration and gentleacceleration;The acceleration intention is divided intoemergency braking,general braking.The method of making the shift schedule is as follows: firstly,the driving style is identified and the shift curve is selected.After selecting the shift curve,real-time monitoring of the driver’s current action is what kind of acceleration/braking intention.According to the different acceleration/braking intention,the shift curve is corrected online.In order to set up the hardware in the loop test bench,the research group has NI real-time measurement and control hardware and software resources,and the real-time vehicle simulation software Truck Sim is the technical condition.Through the hardware in the loop simulation experiment,the correctness of the driving intention recognition method based on fuzzy control is verified.In order to improve the shift quality and the success rate of gear shift,a new linear shift shift actuator was designed based on the original shift actuator.Two speed AMT in the long-term use of the process of mechanical wear,resulting in changes in the position of thegear shift,resulting in shift card lag or even hang up.In order to solve this problem,an online correction strategy of two speed AMT position is designed,which greatly improves the success rate of gear shift and improves the robustness of AMT system.