| In this dissertation, in view of real problems, such as low conversion efficiency, high light-off temperature, a shorter working life as well as Inefficient control of emissions in the working process in Three-Way catalytic Converter(TWC), the theory including mechanism modeling, numerical simulation, and multi-disciplinary design optimization and artificial intelligence, etc. is applied to TWC for exploring a design optimization theories and methods of effective, rational, efficient , longevous and low- emission TWC, Which improve the TWC characteristics of high efficiency, low light-off temperature, a longer working life, as well as efficient emissions control performance in the working process. It is of great theoretical and practical significance to explore new TWC development methods and techniques, which improve the level of emission control of the automotive TWC.In this paper, based on Hunan University"985" the second phase project, " Scientific and technological innovation platform for advanced automotive design and manufacture technology " (electronic control and power emission subproject) (key project of the Ministry of Education [2004] 1), and focusing scientific and technological project in Hunan Province, " research and development on automotive TWC "( Hunan Science and technology research project [2002] 87) , a design optimization theory and methods of highly efficient, longevous and low-emission TWC is studied through the combination method of theoretical analysis with experimental study for the purpose of the successful research and development on TWC with characteristic of higher conversion efficiency, lower light-off temperature, a longer working life, as well as highly efficient emission control process. The main work and innovation of the paper are as follows:A mathematical model of multi-shape TWC performance including sub-models, such as the flow and heat transfer, chemical reactions is established, and side-by-stacking method of the volume control for the conservation of flow and heat transfer equations calculating, as well as the numerical solution in turbulent flow pressure field is put forward. Non-cylindrical monolith represented by elliptical cross section carries out numerical simulation and the effect of ellipticity, the length of monolith coupled with cross-sectional area, the monolith hole density coupled with the hole wall thickness on the TWC performance is analyzed, Which provides a solid theoretical foundation for the study of multi-shape TWC performance.Based on principle of the mass and energy balance of the gas and solid phase (monolith surface) in the automobile TWC, the multi-element response and conversion features mathematical model in the TWC is established including sub-models, such as a multi-million-catalytic reaction mechanism, the catalyst surface coverage changes, Ce storage of oxygen chemical reaction. The simulation of conversion efficiency, the gas composition and distribution, the catalyst surface coverage changes, the cold-start of the TWC as well as the catalyst oxygen storage capacity coincides with the test results very well.The TWC deterioration characteristics model is established from the sintering rate and the response rate including the deterioration process, the TWC aging characteristic is simulated numerically, the results show that in the aging process, an average diameter of Pt particles increases rapidly, and the inactivation factor in the aging rapidly decreases, the activity of the catalyst declines largest. After 100,000 km aging of the TWC, HC, CO, NOx conversion efficiency reduces by 20 percent or more. To this end, TWC anti-aging measures are proposed from catalyst and its distribution, which provides a basis for the structure optimization and performance improvement of TWC.For the first time, multidisciplinary design optimization method is put forward for highly efficient, longevous and low-emission TWC which objective function includes conversion efficiency, pressure loss, mass and thermal shock resistance of TWC, in which based on more shape and working condition, such as geometry, structure and state bound, the overall optimization of highly efficient, longevous TWC is systematically studied. Through the method, the results show that the TWC conversion efficiencyηincreases by 5.42 percent, pressure lossΔp decreases by 6.99 percent, the mass M reduces by 11.68 percent, displacement deformationΔεreduces by 20.91 percent, and overall performance improves up to 8.40 percent. The method provides optimization design for highly efficient, longevous and low-emission TWC with strong theoretical guidance.Using the least square method and least squares support vector machines, the gasoline engine air mass flow measurement dynamic model is built,and Based on oval gear sensor fuel consumption measuring principle,gas mass flow measurement model is established. With the signal of white noise extracted or removed using wavelet analysis , and measurement signal beating and volatility removed by respectively using eliminating hopping signal algorithm and average recursive filter algorithm, and with function chain neural network fitting for the noise data processing, the interference of the various data collection is effectively eliminate. To provide strong technical support for the working environment optimization match in TWC, a fuzzy neural network controller is designed according to the TWC work environment characteristics of the parameters signal,and thermal situation of the working environment monitoring system of TWC is successfully developed by combining Serial Programming with ODBC technology.Gasoline engine TWC bench test results show that, the light-off temperature of the TWC developed in this paper is about 255℃, emissions testing of the TWC matched with the vehicle tested in the National Automotive Test Center (Xiangfan)show that, the exhaust gas conversion efficiency of the TWC developed is more than 92 percent, the performance indicators meets the European IV emission standards limit, the useful time of TWC with Vehicle loaded is up to more than 120,000 km.
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