The Ride Comfort Control Of PHEV During Driving Mode Transfer Process

Today, internal combustion engine vehicles are booming, especially in China. It leads energy crisis, urban air pollution(Haze enveloped in China) and other environment problems. Faced with the world of increasingly stringent vehicle emissions regulations and limited oil resources, the global automotive industry are working to develop a new energy vehicles which have low-emission, high performance, and accepted by consumers. Currently, pure electric vehicle is recognized as new energy vehicles. But subject to imperfect current battery technology and current infrastructure, charging time and gaining mileage will get consumers in troubles. Plug-in hybrid can solve the above problems, and can reduce emissions and improve vehicle efficiency of the system. Currently, it has become the best transitional product which era the automobile industry from oil to electric drive era. Plug-in hybrid has multiple operating mode, operating mode switching, control how could result in improper vehicle ride comfort is deteriorated, so Ride Control of plug-in hybrid operation mode switching is vital, which decide whether it can be accepted by consumers.This paper is bases on a system equipped with CVT single-motor plug-in parallel hybrid electric vehicle. Use of modeling and simulation, road test and bench test, to research the ride comfort when its mode is shifted conducted. The main contents are as follows:① A single-motor plug-in parallel hybrid electric vehicle architecture is introduced. Analysis of steady-state characteristics and dynamic characteristics of the engine, and engine drag torque starting characteristics, build the simulation model of the engine; According to the response characteristics of the motor torque, the motor mode is simplified, establishing a motor mode with first-order response of motor torque demand. In this paper, the focus is not on battery, so the battery with the most simple method of modeling the internal resistance, which greatly reduces the computation time; The structure and principle of wet multi-plate clutch were introduced, according to its torque transfer characteristic, combined with the establishment of a clutch hydraulic clutch model; to minimize fuel consumption targets were carried out for each operation mode CVT ratio optimization, CVT speed ratio control by the look-up table.② This paper studies the torque demand for plug-in uniaxial parallel hybrid system was identified divided uniaxial parallel plug-in hybrid system, each operating region; determining conditions for hybrid vehicles each mode and runs in each mode target torque during power source; determining the condition hybrid system switching between different modes; developed class coordination process mode switching power source and a wet multi-plate clutch control strategy.③ Using Stateflow and Simdriveline to build plug-in uniaxial parallel hybrid system control strategy simulation model for each type of switch mode switching process typical simulation study. The work mode switch dived into wet multi-plate clutch engagement mode switching, wet multi-plate clutch without the operation mode switching, wet multi-plate clutch mode switching. In all types of mode switch in pure electric mode were selected to switch to the engine drive mode, the engine drive mode to the engine, the motor joint drive mode, the engine driving mode is switched to pure electric drive mode as examples of simulation study, and the simulation results are analyzed to verify the effectiveness of the control strategy. And it provides a control strategy selection for bench test and road test.④ To compensate for the lack of simulation, study the real control result. Build a plug-in single-motor hybrid system mode switching Ride Control Strategy verification test bench, for each mode switching performed bench verification; and the mode switching ride control policy to the vehicle controller, were road test of the vehicle, through analysis of experimental data, effectively verify the proposed mode switch practicality and effectiveness of ride control strategy.