Research On Real-time Optimization Energy Management Strategy For CVT Hybrid Vehicles

With the development of society and the improvement of living standards,people's demand for travel is increasing.Not only to the automobile industry has brought huge opportunities for development,but also brought the energy crisis and environmental pollution problems.CVT hybrid vehicles do not rely on charging facilities and have the advantage of continuously changing speed ratio.With its remarkable fuel economy and emission,CVT hybrid vehicles are considered as one of the new energy vehicles with the most promising market prospect.However,the real-time optimization of energy management strategy is the key to exert the advantages of fuel economy and emission of CVT hybrid vehicles.In this paper,a CVT hybrid vehicle is taken as the research object to conduct real-time optimization of energy management strategy.The specific work is as follows:(1)The main drive system parameters of CVT hybrid vehicle are matched,and the forward simulation model is established for the real-time control system,and the accuracy of the main drive system model is verified by the chassis dynamometer.(2)Equivalent fuel consumption minimization strategy(ECMS)control model with CVT target speed ratio and torque distribution coefficient as control variables was established.Considering the physical constraints su ch as CVT speed ratio change rate and engine start-stop,an equivalent fuel consumption minimization strategy(M-ECMS)for multi-objective optimization is established.The power and feasibility of the strategy are verified by MATLAB/Simulink simulation.(3)Because the estimation of equivalent factors depends heavily on the advance information of driving cycles,and the accuracy of its estimation has a great impact on the effectiveness of ECMS.Through the analysis of standard working conditions,the representative driving conditions are selected based on the distribution of rules and equivalent factors,and the LVQ-based condition identifier is trained.The online recognition effect of LVQ condition identifier is verified by the simulation of MATLAB/Simulink.(4)Build adaptive strategy based on driving pattern recognition.Aiming at the inconsistency of battery SOC when driving conditions change,an equivalent factor of representative driving conditions is proposed to modify battery SOC and constrain its changing boundary.The range of free change of battery SOC trajectory is defined by the optimal battery SOC trajectory of each standard working condition.The fuel of this strategy is verified by MATLAB/Simulink simulation.Economy and working condition adaptability.