The Speed And Torque Dual-synchronization Shift Control For Parallel Hybrid Electric Vehicle

The energy pinch crisis and environmental pollution are becoming more serious,while the room for improvement of energy conservation technology in traditional internal combustion engine（ICE）is approaching its limitation.Therefore,the new energy vehicle（HEV）becomes the focus in the field of automotive energy-saving technologies.The HEV combines advantages of low carbonization in pure electric vehicle with edge of strong duration capacity in ICE,thus becoming one of the main development routes of China’s new energy automobile strategy.The single parallel hybrid electric system architecture is widely used in commercial vehicle due to its high power transmitting efficiency and strong torque loading capacity.However,the single axis parallel HEV adopting clutchless shift method has an adverse effect on its gear-shifting process because of the sharp moment increment in its gearbox input part,which makes the gear-shifting process and shift control for HEVs different from that for conventional vehicles.This paper stretches out based on the National Youth Science Foundation Project the Speed and Torque Dual-synchronization Mechanism and Control Strategy for HEV Based on Constraint of Vibration Characteristics.By designing a kind of new shifting way,namely speed and torque dual-synchronization shift control for HEV,it is able to evade problems such as gear-engaging difficulty or shift failure caused by increased input moment,and thus can achieve better shift performance such as lower shift shock and less shift time.Firstly,this paper established the dynamical model for HEV’s shifting process,and discussed possible meshing forms between sleeve and synchronizing ring or idle gear in the process of gear engagement.In addition,it deeply analyzed the mechanism of how the increased input moment exert unfavorable influence on ring-dial or gear-dial process,and furtherly demonstrated why the speed and torque dual-synchronization shifting method can improve the shift performance.Next,on the basis of specifying dynamical constraint condition of speed synchronizing and torque synchronizing,this paper designed speed and torque dual-synchronization shifting control strategy.After the motor’s torque control law was obtained,it also created a kind of fuzzy RBF neural network PID controller to improve performance of motor torque tracing.Then,a co-simulation experiment was performed to furtherly validate competitive edges of speed and torque dual-synchronization shifting method by establishing HEV’s physical model in AMESim and creating control strategy model for dual-synchronization shifting in Simulink.The co-simulation results for upshift and downshift showed that the proposed motor’s control law could ensure speed and torque dual synchronization between pre-meshing gear pair when gear-engaging starts.Finally,the upshift and downshift bench experiments were carried out respectively both in conventional shifting way and dual-synchronization shifting method.The bench test results showed that compared with traditional gearshift,the proposed speed and torque dual-synchronization shifting method could lessen shift time and relieve shift shock significantly,thus had remarkable superiority.