Research On The Energy Management Strategy And Parameter Optimization Of Parallel Hybrid Electric Bus

New energy automobile industry draws wide attention as people calls more forenergy consumption and environment protection. Nowadays, PHEV (Parallel HybridElectric Vehicle) has been widely applied in the field of domestic city bus. Energymanagement strategy is very important to PHEV’s energy-saving effect. A lot ofresearch around this aspect has been done both at home and abroad, which providestheory method for PHEV’s optimization and also proposes many strategies. Needed topoint out that, these studies focus more on the theoretical analysis and simulation. Inview of this, the thesis focuses more on real implementation and road experiment. Onthe other hand, parameters selection of the powertrain has important influence on theperformance of the vehicle, thesis carries on related research.The thesis builds coaxial parallel hybrid simulation model based onMatlab/Simulink environment. It’s convenient to use the model to evaluate thevehicle fuel economy under different strategies. The thesis confirms the relatedparameters in the simulation model by vehicle parameter calibration test, and throughthe comparison between road test results and simulation results, finally verifies thereliability and accuracy of the model.The thesis expounds two kinds of typical energy management strategy-rulebased and instantaneous optimization strategy, introduces the two strategiesrespectively to the simulation model and analysis their difference through simulationunder typical working condition. Combining the advantages of them, rule basedinstantaneous optimization strategy is proposed.The thesis realizes the strategy in an existed HCU (Hybrid Control Unit).Introduction of the HCU is claimed at first, then the method to realize upper strategyand coordination between upper strategy and low-level control is explained.The thesis verifies the effect of proposed strategy through road experiment.Comparative experiment under typical working condition was conducted usingexisted rule based strategy and new proposed strategy. Essential variables of theexperiment were compared and vehicle energy flow was analyzed. Result shows that the proposed strategy could improve the vehicle fuel economy.The thesis develops a coaxial parallel hybrid simulation system based onsimulation model, which could automatically come out powertrain parameterselection scheme, optimize the parameter and evaluate vehicle performance.Parameter selection of PHEV could be completed quickly and effectively using thissystem.