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The objective of this study is the design, construction and evaluation of a Selective Particle Size (SPS) sampler able to provide continuous delivery of diesel soot particles of specific size ranges. The design of the sampler combines principles of aerosol transport phenomena and separation technologies. Particles smaller than a given size are removed from the exhaust by diffusional deposition, while removal of particles above a given size is achieved by low pressure inertial impaction. The main application of the developed sampler is the exposure of biological samples such as cell and tissue cultures to selected sizes of diesel exhaust particles. By applying the SPS sampler to diesel exhaust it is demonstrated that it is possible to obtain two aerosol streams with widely separated particle size distributions (of nanometric dimensions), suitable for biological exposure studies.

Diesel Particulate Filters (DPFs) need to be periodically regenerated in order to achieve efficient and safe vehicle operation. Under typical diesel exhaust conditions, this invariably requires the raising of the exhaust gas temperature by active means, up to the point that particulate (soot) oxidation can be self-sustained in the filter. In the present work the development path of an advanced catalytic filter technology is presented. Full scale optimized Catalytic Diesel Particulate Filters (CDPFs) are tested in the exhaust of a light-duty modern diesel engine in line with a Diesel Oxidation Catalyst (DOC). The management of the DOC-CDPF emission control system is facilitated by a virtual soot sensor in order to ensure energy-efficient operation of the emission control system.

The increasing need for controlled diesel engine emissions and the strict regulations in the abatement of diesel exhaust products lead to an ever increasing use of Diesel Particulate Filters (DPFs) in OEM applications. The periodic regeneration of DPFs (oxidation of soot particles) demands temperatures that rarely appear during engine operation. It is therefore necessary to employ direct or indirect catalytic measures. In the present work, the development and synthesis via aerosol-based routes, of nanostructured base metal oxides for direct soot oxidation, along with their characterization and their evaluation in engine exhaust is described. The synthesized powders were characterized with respect to their phase composition and morphology. XRD, SEM and TEM analysis have shown the nanostructured character of the powders, while Raman spectroscopy was employed for the preliminary characterization of the materials surface chemistry.

DPF has become widely known as an indispensable after-treatment component for the purification of the particulate matter in the diesel exhaust gas. But, in order to correspond to further regulation strengthening such as carbon dioxide emission regulation and number-based particulate matter emission regulation, it must be necessary also for DPF to keep improving its performance. In this study, it was examined how to improve both the filtration efficiency and the oxidation efficiency of PM regarding the catalyzed DPF. SiC-made 10mil/300cpsi-OctoSquare asymmetric cell structure was chosen for the DPF substrate and PM oxidation catalyst was coated on the surface of the filter wall as a layer with the device of the coating method. As a result, it was found that the layer coated DPF has advantage on the filtration efficiency without soot accumulation and efficiency was similar to an uncoated one with 0.1 g/l soot loading.

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.