Study On The Multi-Energy Management Strategy For ISG (Integrated Starter/Generator) Parallel Diesel Hybrid Electric Vehicles

The Hybrid Electric Vehicle (HEV) which combines the internalcombustion engine, electric motor and Nickel-metal hydride battery(NiMH)can achieve higher fuel economy and the same range compared with thetraditional internal combustion engine is the most promising next generationvehicle type.The energy management control strategy is this thesis is based on thecity bus assembled with Integrated Stater/Generator (ISG) parallel dieselhybrid power-train which inserts a thin permanent magnetic motor betweenthe diesel engine and the flywheel. This type of HEV is a compact, highlyintegrated hybrid assemble which can be adapted into with all kinds oftransmissions to realize the functions like auto-stop, motor assistance andregeneration.The energy management for HEV decides the energy distributionbetween the electric motor and the internal combustion engine is the keytechnology to achieve the fuel economy target. Because of the sophisticatedcharacteristics of the components, the energy management is a multi-purposeoptimal question. And as to the intelligent property issue, it also becomes theimportant item for the commercialization of the HEVs.1) Lastest development about HEVs are collected and classified toshow the trend of HEV development. And the strengths andweakness of various methods for the control strategies are compared.2) The construction, functions and configuration of the ISG dieselhybrid power-train are presented in this paper. The hierarchicalarchitecture of ISG hybrid control system is designed as well as theCAN protocol and the hardware for HCU (hybrid control unit) isalso developed. 3) By adopting the standard ‘V’ Cycle process， a forward-lookingmodel is developed in the Matlab/Simulink environment. Themethod for functions like regeneration brake, SOC balance, andmotor assistance in the multi-energy management strategy arecompared by the simulation model and a complete rule-basedmulti-energy control strategy is built.4) The control stragegy is the key work in this thesis, including theauxiliary strategy and dominant strategy. The auxiliary strategy isused to realize the auto start-stop function and model switchingfunction. The dominant strategy is the torque distribution strategywhich is ultized by the fuzzy-optimal method to fulfill functions likeregeneration, SOC balance and motor assistance. The fuzzy-optimaltorque distribution deduces its control rules by the optimal algorithmand set various rule-base to implement different functions. Thistorque distribution method which can achieve a good trade-offbetween the conflicting dynamic and fuel-economy targets is themain innovation.5) The bench test and road test are conducted to validate theperformance of the ISG hybrid city bus after fine-tuning the controlstrategy using the calibration system. The ISG motor is able toproduce the maximal350N.m torque and the maximal torque of thewhole power-train is equal to the original6-cylinder engine with27%improvement in low speed range. The0-50km/h accelerationtime is9.5%less than the original bus. The fuel economy is testunder the4-speed cycle with the requirement that the SOCdifference is less than1%and the result shows that there is25%improvement compared to the original bus.