Study And Improvement Of Underhood Thermal Management Of A New Vehicle

Underhood thermal management basically research on the airflow characteristic in the underhood and the performance of cooling system, With the increasing popularity of automotive vehicles, that will influence driving safety, riding comfort and fuel economy dramatically. Compared with wind tunnel test, the simulation technique could help to reduce cost and shorten development cycle,thus to speed up launching new vehicle and improve the competition of products. On the background of a certain new vehicle, whose engine is midship,of a famous automobile company, the systematic study on underhood thermal management is carried on based on computer simulation technology.Three-dimensional geometry is simplified to build qualified polyhedral mesh with the help of STAR CCM+firstly. Investigation on the airflow property and temperature distribution is carried out at three different conditions:idling, sloping, high speed. After that problems of inverse flow and high temperature besides exhaust manifold are detected. Based on the outcome from3D software, the result of thermal equilibrium performance analysis in AMEsim shows that the water temperature of engine outlet is too high in the sloping case.Finally, several schemes are introduced and optimization principles of baffle and thermal shiled are settled based on the structure characteristics of the vehicle. Then, in view of installing viability, air fins and thermal shroud are designed. The simulation is carried on again based on the new model and the result shows this proposal could increase air flow of the cooling system effectually,also decrease thermal radiation evidently. The water temperature of engine outlet decreases to104.43℃by3.6%, according to the ID thermal equilibrium analysis, which achieves the design requirement. By this3D/1D coupling numerical simulation method, the performance of underhood thermal management can be evaluated effectually in an early stage of vehicle development. Different proposals can be compared with each other to improve the thermal performance taking the advantages of low cost, short cycle and swift remodel of computer simulation. It provides approaches and references for thermal management performance analysis of this kind of vehicles.