Integrated Analysis Of Pure Electric Vehicles Multiple Thermodynamic Systems Coupling Underhood

It is environmental pollution,greenhouse effect and energy crisis across the whole world that bring much inconvenience.Under the dual pressure of environmental pollution and energy shortage,many countries are devoted to develop Electric Vehicles(EV)to meet the requirements of emission regulation and energy saving and environmental protection.Because of compact form of EV underhood,multiple thermodynamic systems have thermal interaction effects in the underhood.These effects directly impact working performance of thermal management systems even bring negative effect to the vehicle dynamic,economic performance and comfort.Consequently,this paper carries out integrated analysis of EV multiple thermodynamic systems,including battery and electric machine thermal management system and air-conditioning system,for simulation and optimization of thermal management system,to improve computation and analysis methods of EV thermal management system coupling simulation.In the process of EV multiple thermodynamic systems simulation platform building,it was used a new simulating method that 1D unites with 3D and theoretical characterization unites with experimental characterization.Based on the heat transfer theory,the cooling constructions of battery and electric machine have been characterized by 1D theory.According to the experiment data of condenser,evaporator,compressor,expansion valve,the mathematic relation between influence factors and components was built.The heat transfer and flow model of radiator and condenser and rotational model of fan in the underhood has been characterized by 3D theory.EV multiple thermodynamic systems coupling underhood 1D/3D co-simulation platform has been established completely by MATLAB compiling control FLUENT.It was put forward a set of EV thermal management system performance evaluation method by researching of multiple thermodynamic system integrated analysis and design matche methods.This method specific function as follows by combining with simulated result of platform: components of matching and optimizing,evaluation of system operation under a variety of conditions,analysis of thermal interaction problems between multiple thermodynamic systems.Finally,the underhood was determined to the rearr-facing condenser arrangement form by comparing and analyzing the result of the front-and rear-facing condenser form,and combining with the thermal management system performance evaluation method.Based on the 1D/3D co-simulation platform,computed on the rear-facing condenser form under different operationg conditions,such as air conditioning load,driving state,coolant flow,ambient temperature and fan speed.It simulated thermal parameter trend of components,observed thermal current field distribution,analyzed thermal interaction problems between multiple thermodynamic systems.By comparing and analyzing the result of simulation result,the action characteristic of different influencing factors has been studied,the operation effect of multiple thermodynamic system has been evaluated.So rational suggestions of EV thermal management systems' design and control policy has been put forward.