Integrated Analysis Of Engine Thermal Management In Underhood And Vehicle Air Conditioning

Automobile industry is an important symbol of the national economy development andsocial civilization. Nowadays building a conservation-minded society is advocated, whilethe automobile has become a large energy consumer. The vehicle thermal managementtechnology integrates the vehicle thermal management system and objects with the vehicle,which optimizes the energy use and distribution to improve the vehicle performance ofdynamic, fuel economy, comfort, safety, reliability and emission. It has an importantpractical significance of integrated analysis of engine thermal management in underhoodand vehicle air conditioning through advanced vehicle thermal management design conceptand modern automotive design methods.This paper first describes the composition and calculation of vehicle air conditioningload and the method to compose an efficient air conditioning system, then analyze theimpact of air conditioning load and refrigerating capacity. Propose using the equilibriumtemperature of the passenger compartment to evaluate the air conditioning system matchingwith the vehicle. Develop and design the software of air conditioning matching with thevehicle using VBA language based on Excel, which makes the matching and analysis ofvehicle air conditioning systems automatic and digital with vehicle air conditioning heatingload calculation software and vehicle air conditioning refrigeration systems composingsoftware.Build the model of engine cooling system, and develop and design the software ofengine cooling system one dimensional simulation using graphical user interface(GUI) inMATLAB environment. Propose the method of one-dimensional and three-dimensionalcoupled simulation of vehicle air conditioning, engine cooling system and the environmentin underhood, which makes the simulation results more realistic and reliable. Get thevehicle heating load through vehicle air conditioning heating load calculation software and obtain the refrigerating capacity using the vehicle air conditioning refrigeration systemscomposing software, then evaluate the vehicle air conditioning system matching with thevehicle by vehicle air conditioning matching the vehicle software. Accomplish theintegrated analysis of engine thermal management in underhood and vehicle airconditioning, and lay the foundation for building the basic platform of the vehicle thermalmanagement.The evaluation methods of integrated analysis of engine cooling system, airconditioning system and underhood thermal environment is established. Cooling constantindex K is used to predicate the heat dispersion performance of the radiator. Evaluate thesituation of air conditioning system matching the vehicle with the equilibrium temperatureof passenger compartment at some condition. Analysis the thermal environment by thevelocity vector maps and temperature distribution maps from three-dimensional simulationresults.Analysis the thermal coupling characteristics of condenser and radiator. The COP ofvehicle air conditioning system and the heat dissipation of radiator are used tocomparatively analyze coupled system with uncoupled system. At idle speed,40km/h and100km/h three calculation conditions, compared with the uncoupled analysis, the COP ofthe air conditioning system was reduced by43.51%,10.95%and28.93%, the heatdissipation of radiator was reduced by0.32kW,2.18kW2.45kW.Through the thermal environment simulation experiment of vehicle air conditioningsystem, the simulation results are compared with the experimental results, the relative erroris less than5%, to verify the feasibility of the proposed one-dimensional andthree-dimensional coupled simulation method and prove the correctness of air conditioningsystems and vehicle matching analysis method.