Optimal design of axial noble metal distribution for improving the performance of a dual monolithic catalytic converter

Abstract

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.In practical applications, monolithic catalytic converters are operated at non-isothermal conditions. In this case, the active metal distribution along the length of the converter may influence its performance. Indeed, better conversions can be achieved by controlling the distribution of the same quantity of active material. In this study, we used a one-dimensional catalyst model to predict the transient thermal and conversion characteristics of a dual monolithic catalytic converter with Platinum/Rhodium (Pt/Rh) catalysts. The optimal design of a longitudinal noble metal distribution of a fixed amount of catalyst is investigated to obtain the best performance of a dual monolithic catalytic converter by using a micro genetic algorithm with consideration of heat transfer, mass transfer, and chemical reaction in the monolith during FTP-75 cycle. The optimal design for the optimal axial distribution of the catalyst is determined by solving the multi-objective optimization problems which are to minimize both the CO cumulative emissions during FTP-75 cycle, and the difference between the integral value of a catalyst distribution function over the monolith volume and catalytic surface area per unit monolith volume.