Computer aided assessment and optimization of catalyst fast light-off techniques

Abstract Strict future legislation standards are forcing the car industry to employ new techniques for reducing exhaust gas emissions. Most of these techniques focus on accelerating the appearance of catalyst light-off and are thus called fast light-off techniques (FLTs). Optimized exhaust systems comprising FLTs will be able to meet the forthcoming legislation standards for the United States [low emissions vehicle (LEV) and ultra-low emissions vehicle (ULEV)] and the European Union (Stage III). The most promising active and passive FLT systems are briefly reviewed. Computer aided optimization of such systems can be realized with the help of specific computational tools, which are briefly presented in this paper, and according to a concept optimization methodology, which is also discussed. The results indicate an increased sensitivity of FLT systems’ performance over the selected values of certain design and operating parameters that were featured in the examples presented. Moreover, by comparing the computational results with knowledge gained from experiments and testing, the paper indicates that, given the suitable computational tools, the optimization procedure can take place in a most cost-effective manner by substituting many experiments with computer test case runs.