Simulation Research on Automobile Exhaust Waste Heat Thermoelectric Generation System
|School||Wuhan University of Technology|
|Keywords||Automobile Waste Heat Thermoelectric Generator (TEG) the simulationof hot side gas box the simulation of cold side water tank|
In recent years with the continuously rapid development of the social economy, the responsibility of energy conservation and emission reduction already has become a great and formidable task for all people based on the reality that our country’s energy consumption has greatly increased, oil imports continuously keep breaking records and the dependence on other national is rising. As one of the main oil consumption industry, the automobile industry will undertake more and more social responsibility. It has been one hundred years history since the internal combustion engine is used for the traditional power of automobiles. So people are constantly pursuing the progress of technology aiming to improve internal combustion engine performance. However, due to the limit of engine combustion cyclic inherent characteristic and a large part of fuel consumption energy is wasted through exhaust gas. the thermal efficiency of traditional internal combustion engine is always low. The thesis has carried out a series of research work on the exhaust gas based on the use of thermoelectric material.The experiment and simulation research of TEG hot side gas box and cold side water tank has been carried on. During the hot side research, the surface temperature of hot side gas box and inlet and outlet of exhaust temperature MAP of water tank had been acquired from experiment. Established the engine simulation model integrated with gas box based on the gas box pressure drop equivalent model simulated by the exhaust back pressure experiment results. Through the simulation, the paper has acquired the exhaust flow MAP which is the input parameters to calculate the TEG generate electricity performance in the following work.moreover, has analyzed the effect of gas box influencing on the engine power and economy performance and air intake system noise effect. During the cold side research, established the engine simulation model TEG integrated with cooling system combined with the water tank internal heat transfer effects theory. Analysis of the different water tank connecting ways in engine cooling system, simulation results show that when access in the small loop stage, standard engine warm-up time will extend, if cycle access in the large stage, TEG cooling water tank temperature is rising but not synchronized and the different water temperature when achieving steady state. Aim to eliminating above problems, the connection way of three cooling water tanks has chosen the parallel structure compared with series structure, in addition, optimizing the TEG cooling water tank capacity and the cooling liquid inlet and outlet diameter size. Considering the TEG influence on the engine cooling system, the thesis has optimized the water tank capacity from the point of thinning the thickness of the water tank and its processing manufacturability. The results show that the water temperature variation among water tank has good synchronicity, the time obviously has been shortened when achieving steady state and the cold side has good performance after optimized.Further, comprehensive with the study on TEG cold and hot side, established the single module generate electricity model, designed the electrical connection topological structure among modules combined with the research on the surface temperature of hot side gas box. Established the TEG system generate electricity model and integrated with the vehicle, the simulation and analysis of TEG performance have been carried on the integrated model based on the vehicle driving cycles. The TEG output performance is poor when the low load conditions, After Improved design and analysis. Simulation results indicated the improvement measures effect is obvious. To further improve the difference in temperature, this paper also has carried out the research on the independent cooling system realizing the dramatically improvement on TEG output performance but little increase on the vehicle fuel consumption, what is more, realizing the promotion of pure output power and reduction of fan energy consumption through the optimizing of cooling fan speed.