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Study on Numerical Simulation of Fast Aging Characteristics of Three Way Catalytic Converter Based on Detailed Reaction Mechanism

Author: GuoHua
Tutor: GongJinKe
School: Hunan University
Course: Power Machinery and Engineering
Keywords: three-way catalytic converter reaction mechanism aging kinetics model numerical simulation
CLC: U464.134.4
Type: Master's thesis
Year: 2009
Downloads: 117
Quote: 4
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Abstract


The vehicle has brought human being not only convenient traffic and social prosperity but also a great deal of harm to the environment. Thus, it’s the major development issue to reduce exhaust pollution in this field. Three-way catalytic converter (TWC) is the most successful aftertreatment device of controlling exhaust pollution. With emission regulations getting stricter, all light vehicles are required to load with OBD (On-Board Diagnostics), which ask the TWC higher durability. So it’s focal point to research the TWC aging characteristics to further ensure the stability of efficiency in the long-term work to control vehicle emissions.Based on detailed reaction mechanism and oxygen storage reaction mechanism, a kinetic model of two-dimension single-channel of the monolith was established. After analyzing three-way catalytic aging forms, aging mechanism was studied from sintering rate and reaction rate, by which the relative activity of catalyst could be accounted. Combined with the kinetic model and the TWC aging mechanism, an aging kinetic model of the monolith was created.Based on this model, a fluid model of two-dimension single-channel of the monolith was established in FLUENT. Coupled with Chemkin software, numerical simulation of fast aging process was done according to fast aging bench test condition. By simulation, temperature and oxygen concentration distributions were obtained, so the relative activity of catalyst with certain aging hours could be calculated by MATLAB. Therefore, characteristic conversion efficiency, light off characteristics and air fuel ratio characteristics before and after aging were obtained. The simulation results were agreed mainly with the bench test. Thus it provided an effective theory method to analyze the performance of TWC aging process. Then the relative activities of catalyst in different positions were analyzed. The impacts of inlet diffuser and porosity on aging characteristics were analyzed, by which the structure and performance of the TWC could be a certain extent optimized. At last, according to the aging mechanism and distribution of the relative activity of catalyst, anti-aging measures were put forward.

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CLC: > Transportation > Road transport > Automotive Engineering > Automotive engine > Reciprocating engine > Components, parts > Valve > Intake and exhaust systems
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