Search Results

In order to use modeling as a predictive tool for real-world particulate filter designs (segmented filters, non-axisymmetric designs), it is necessary to develop reliable 3-dimensional models. This paper presents a 3 d modeling approach, which is validated against engine-bench measurements with both FBC and CDPF systems. Special emphasis is given to the prediction of the transient inlet flow distribution, which is realized without resorting to external CFD software. The experimental and modeling results illustrate the 3-d nature of the problem, induced by the heat capacity and conductivity effects of the cement layers. It is possible to predict the localization of regeneration in certain areas of the filter (partial regeneration), as a result of poor heat transfer to thermally isolated regions in the filter. The accuracy of the model was validated by extensive comparisons with temperature measurements in 30 positions inside the filters and at various operating conditions.

The possibility to employ a single-brick system with a catalyzed filter (CDPF) for the after-treatment of diesel engines is potentially a promising and cost-effective solution. In the first part of this paper, the effectiveness of a single brick CDPF system towards reducing the gaseous CO and HC emissions is investigated experimentally and computationally. The second part of the paper deals with the behavior of single brick catalyzed filters compared with two brick systems comprising an upstream oxidation catalyst. The main differences of the two systems are highlighted in terms of regeneration efficiency and thermal loading, based on simulation results. The modeling work is based on a 3-dimensional model of the catalyzed filter and an axi-symmetric model of the oxidation catalyst. Model validations are presented based on engine bench testing.