Heat Balance Analysis And Improvement Of Engine Compartment For X111 Passenger Car

Heat transfer process is controlled and optimized by heat balance and thermal management from view of integration and the overall angle to make sure the key component or the system work reliably and efficiently.The vehicle type studied in this thesis is a brand-new vehicle type. The engine compartment arrangement and the related disposition are different. Its engine cooling capability and the engine apartment temperature field also changed. In order to estimate the engine cooling system whether can undergo the market need, whether there is over heat problem in the engine apartment, the system analysis of engine apartment thermal equilibrium question, the hot evaluation test, and the improvement of the cooling system or the engine apartment arrangement to satisfy the request according to the actual situation are needed. In order to satisfy the design requirements, the basic parameter is calculated firstly in this thesis, and the verification is made through the simulation tests. In order to solve the over heat of the cooling system discovered in the simulation tests , by using the STAR-ccm+, through the simulation analysis, the hot backflow question was discovered and solved, the verification was made finally through the line-up test method, which causes the product to satisfy the design requirements finally. In this project, the simulation analysis and the environmental test were used together, which reduced the development cycle, the independent development experience was gained further, the vehicle thermal balance research level was raised.This main research contents in this thesis are as following:(1)Through the contrast of the road test data and simulated road test data, the difference between the analysis of actual path condition and the simulated condition experiments was studied.Make tests with the same vehicle in high temperature and at high speed on highway and in the environment simulation cabin, record parameters, such as engine water temperature, oil temperature, intake air temperature, throttle angle, and so on, to analyze the deference of the engine state at the same load and environment condition in the two test by comparing the parameters. The analysis is helpful to establish reasonable laboratory test evaluation criteria, which makes the correct establishment to the test vehicle.(2)Through the research of the domestic road condition and the regional climatic conditions, consider the simulated experimental condition, constitute the reasonable inspection test method.Investigate and study domestic typical road condition, research domestic road construction standard, on the other hand investigate the domestic typical climatic conditions, provides the basis for the indoor simulation test condition determination, enables the vehicle to carry on the experimental appraisal under the appropriate climatic conditions, which makes the paper vehicle under the actual exploitation conditions in reasonable level.(3)Analyze the air flow structures via the simulation by using STAR-ccm+.Utilizes the CFD technique, analysis engine apartment flow field condition, through the flow field analysis vehicle low-speed test problem, instructs the design department to solve hot backflow problem in the vehicle, which will enhance the vehicle performance.(4)Through the measurement of the flow field and the thermal field, the design proposal and the improvement was confirmed, and the similar vehicle which sold in the market were compared by environment tests. In the experimental study process, contrast among the vehicle sold in the market provides the basis for the correct localization for the paper vehicle level.(5)By optimizing the design and the engine apartment arrangement, the thermal balance level is raised, heat harm of the engine apartment is solved.The synthesis using of the road test, the simulation tests and the CFD analysis method, through the reasonable seal method, certain hot backflow problem was solved finally, further the vehicle heat balance level was reached, the operation requirements was achieved.