Mode Transition Rule For Dual Mode Power-split Hybrid Electric Vehicle

Hybrid electric vehicle has high power density,long driving mileage,and can help alleviate the fuel energy shortage and air pollution problem.Among typical HEV architectures,power-split architecture combines the advantages of parallel and series architecture.It can achieve electrical variable transmission and multi-mode by equipping power-split device and clutch/brake.Power-split HEV has been the most competitive technical solution since it can deep tap the system performance potential.The mode transition rule of a dual mode power-split HEV in which configuration and component parameters are given is the focus of the dissertation.Content includes powertrain system analysis and modeling,development of energy management strategy,bench test and design and modification of mode transition rule.The component models are developed by analytical method and experimental data,and then be integrated to an integral simulation platform for the energy management strategy development,and mode transition rule design.A comprehensive efficiency model for power-split device considering the mechanical loss is proposed and the model precision is validated by conducting static experiments.Adaptive Equivalent Consumption Minimization Strategy(A-ECMS)is developed for the dual mode power-split HEV to optimize the equivalent fuel consumption.An updated scheme named Energy Efficiency Maximize Strategy(EEMS)is developed to help reduce the online computational burden in A-ECMS while guarantee the fuel ecomony.Dynamic mode transition rule in which velocity and battery power are input parameters is developed by using linear programming.By using ECMS as optimization solver,economic mode transition rule is developed by selecting velocity,throttle and battery power as input parameters.The ecomonic mode transition rule significantly improves the fuel ecomony,compared to the traditional heuristic rule.The difference between the mode transition rule in HEV and gear shift rule in tradition cars,also the relationship between mode transition rule and energy management strategy are discussed.A modification factor is defined to modify the economic mode transition rule to help avoid the frequent mode transition phenomenon.The simulation results show that an appropriate modification factor may increase the minimum time interval between two sequent transitions can be to 10 s at the cost of little additional fuel consumption,in other words;achieve the cancellation of frequent mode transition.