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Diesel particulate filters (DPFs) are commonly employed in modern passenger cars to comply with current particulate matter (PM) emission standards. DPFs requires periodic regeneration to remove the accumulated matter. During the process, high-concentration particles, in both nucleation and accumulation modes, are emitted. Here, we report new information on particle morphology and chemical composition of fine (FPs) and ultrafine particles (UFPs) measured downstream of the DPF during active regeneration of two Euro 5 passenger cars. The first vehicle was equipped with a close-coupled diesel oxidation catalyst (DOC) and noncatalyzed DPF combined with fuel borne catalyst and the second one with DOC and a catalyzed-diesel particle filter (CDPF). Differences in PM emission profiles of the two vehicles were related to different after treatment design, regeneration strategies, and vehicle characteristics and mileage. Particles in the nucleation mode consisted of ammonium bisulfate, sulfate and sulfuric acid, suggesting that the catalyst desulfation is the key process in the formation of UFPs. Larger particles and agglomerates, ranging from 90 to 600 nm, consisted of carbonaceous material (soot and soot aggregates) coated by condensable material including organics, ammonium bisulfate and sulfuric acid. Particle emission in the accumulation mode was due to the reduced filtration efficiency (soot cake oxidation) throughout the regeneration process.

Combust. 31,. Cette approche peut être utilisée comme un moyen de compréhension de phénomènes complexes qui régissent le catalyseur impliquant plusieurs domaines de la physique. Elle représente aussi un outil de simulation pertinent dans la définition des architectures de ligne de post-traitement et dans le contrôle des émissions polluantes. Le potentiel de l'approche pour traiter l'ensemble des organes de post-traitement est illustré par des résultats sur un catalyseur trois voies (3WC), un catalyseur d'oxydation Diesel (DOC), un piège à NOx (LNT), un système de catalyse sélective des NOx (SCR) et un filtre à particules (DPF). Cette capacité à fournir avec un bon compromis temps/précision des informations intéressantes pour aider au développement de systèmes de post-traitement de plus en plus complexes rend la simulation 0D particulièrement attractive. Oil & Gas Science and Technology -Rev. IFP, Vol. 64 (2009) and Technology -Rev. IFP, Vol. 64 (2009) , No. 3, pp. 285-307 Copyright © 2009, Institut français du pétrole DOI: 10.2516/ogst/2009023 Simulation Tools for Powertrain Design and Control Outils de simulation pour la conception et le contrôle du groupe motopropulseur D o s s i e r Oil & Gas Science

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