Matching And Simulation Modeling Of Four-wheel Drive Plug-in Hybrid Vehicle

The depletion of oil resources and the increasingly serious environmental pollution make the development of new energy vehicles has become an inevitable trend. Because there are some shortages in pure electric vehicles, such as the short mileage, slow charging and so on, the plug-in hybrid electric vehicles as a transitional product emerge as the times require. It can charge the energy storage device through the power grid storage, reduce the dependence on oil fuel and use cost, and ensure the mileage. In the plug-in hybrid electric vehicles energy saving ability depends largely on the parameters matching and control strategy. Therefore, the research on the parameters matching and control strategy of the plug-in hybrid electric vehicles has important significance.For the target to improve the fuel economy, in this paper based on the transmission system of the four-wheel drive plug-in hybrid electric vehicle, some researches are done, such as parameters matching, formulating control strategy, and establishing the model of the dynamic transmission system. Details are as follows:① Parameters matching of the four-wheel drive plug-in hybrid electric vehicle. Taking the dynamic performance as the goal, at first the total required power of power source and then the power ranges of engine and motor which meet the design requirements are calculated, and in that power ranges three groups of different power combination are selected. Based on the selected power parameters, the ratios of AMT and main reducers are determined. And based on the required of mileage and the parameters of drive motor, the parameters of the battery pack are matched. At last, a, b and c groups of parameters of different dynamic transmission system are got.② Formulating control strategy and establishing the model of the dynamic transmission system. The vehicle control strategy mainly includes the mode switching and energy distribution, and this paper applies the simple and reliable logic threshold control strategy. Based on the parameters of the different power source, the thresholds are set to control the mode switching. On energy distribution, when the engine or the drive motor works alone, the require power is supplied by themselves; when the engine and the drive motor work together, the engine works in the optimal economic line and the excess energy is used for charging while the lacking energy is supplied by the drive motor. This paper employs reverse simulation and based on Matlab/Simulink the simulation models are established. The component models mainly include the road model, the AMT model, the mode switching model, the required energy allocation model, the engine model, the drive motor model, the BSG model and the battery pack model. The simulation model of the vehicle dynamic transmission system is got with connecting all the component models according to the reverse order of power transmission line.③ Simulation and establishing. Under the three different cycles which are NEDC, UDDS and HWFET and two different modes which are CD mode and CS mode, energy consumption economic of a, b, and c groups of the vehicle dynamic transmission systems is simulated in this paper. The simulation results show that in CD mode a group of dynamic transmission system in which the power of engine is the largest while the power of the drive motor is the lowest has the lowest fuel consumption and the most electric energy, and c group of dynamic transmission system in which the power of engine is the lowest while the power of the drive motor is the largest has the most fuel consumption and the lowest electric energy; in CS mode the SOC of the battery pack of three groups of dynamic transmission system are maintained at about 0.3, besides that, the fuel consumption of a group of dynamic transmission system is the lowest while b group is in the middle and c group is the highest. Taken together, the parameters of a group of dynamic transmission system are selected as the final result.