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The DEXA Cluster consisted of three closely interlinked projects. In 2003 the DEXA Cluster concluded by demonstrating the successful development of critical technologies for Diesel exhaust particulate after-treatment, without adverse effects on NOx emissions and maintaining the fuel economy advantages of the Diesel engine well beyond the EURO IV (2000) emission standards horizon. In the present paper the most important results of the DEXA Cluster projects in the demonstration of advanced particulate control technologies, the development of a simulation toolkit for the design of diesel exhaust after-treatment systems and the development of novel particulate characterization methodologies, are presented. The motivation for the DEXA Cluster research was to increase the market competitiveness of diesel engine powertrains for passenger cars worldwide, and to accelerate the adoption of particulate control technology.

The paper presents the results of the STYFF-DEXA project which has delivered an attractive computational approach based on detailed treatment of the filtration and regeneration processes inside diesel particulate foam filter materials. The new approach can provide accurate macroscopic material parameters by utilizing tomographic data and novel algorithms to reconstruct three-dimensional digital representations of the foam material microstructure. The Lattice-Boltzmann (LB) Method is used as a basis for computing the flow within the foam pores. The latter is coupled to sub-models of particle transport/deposition and size distribution based on the very efficient Method of Moments which employs a probability density function representation of the suspended soot. Additionally, acoustics modelling functionality has been developed which permits the evaluation of the engine noise attenuation capabilities of the foams and similar microstructures.