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La1-xAxNi1-yByO3 nanostructured perovskite-type oxides catalysts (where A = Na, K, Rb and B = Cu; x = 0, 0.2 and y = 0, 0.05, 0.1), also supporting 2% in weight of gold, were prepared via the so-called “Solution Combustion Synthesis (SCS)” method, and characterized by means of XRD, BET, FESEM-EDS and TEM analyses. The performance of these catalysts evaluated. The 2 wt.% Au-La0.8K0.2Ni0.9Cu0.1O3 showed the best performance with a peak carbon combustion temperature of 367°C and the half conversion of CO reached at 141°C. The same nanostructured catalyst, deposited by in situ SCS directly over a SiC filter and tested on real diesel exhaust gases, fully confirmed the encouraging results obtained on the powder catalyst.

Four perovskite catalysts LaBO3 (B = Cr, Mn, Fe, Ni), also supporting 2% in weight of gold, were prepared via the so-called “Solution Combustion Synthesis (SCS)” method, and characterized by means of XRD, BET, FESEM-EDS, TEM, O2-TPD and CO-TPR analyses. The performance of these catalysts towards the simultaneous oxidation of soot and CO was evaluated. The 2 wt.% Au-LaNiO3 showed the best performance with a peak carbon combustion temperature of 431 °C and the half conversion of CO reached at 156 °C. The same nanostructured catalyst, deposited by in situ SCS directly over a SiC filter and tested on real diesel exhaust gases, fully confirmed the encouraging results obtained on the powder catalyst.

Several Li-Cr delafossite catalysts were prepared via the so-called “Solution Combustion Synthesis (SCS)” method, characterized and tested as catalysts for the combustion of diesel soot. These catalysts already showed appreciable activity at 350 °C even under loose contact conditions. An in situ SCS method was tailored to the preparation of a LiCr0.9O2 -catalyzed trap based on a SiC wall-flow monolith. Engine bench tests on these catalytic traps showed that the presence of the catalyst enabled both a more complete regeneration and a one-third fold reduction of the regeneration time compared to the case of a non-catalytic trap.

The growing demands on fuel economy and always stricter limitations on pollutant emissions has increased the interest in the ignition phenomena to guarantee successful flame development for all the spark ignition (SI) engine operating conditions. The initial size and the growth of the flame have a strong influence on the further development of the combustion process. In particular, for the new FIAT generation of turbocharged SI engines, the first times of spark ignition combustion are not yet fully understood. This is mainly due to the missing knowledge concerning the detailed physical and chemical processes taking place during the all set of the flame propagation. These processes often occur simultaneously, making difficult the interpretation of measurements. In the present paper, flame dynamic was followed by UV-visible emission imaging in an optical SI engine.

Nano-structured bulk Li-substituted La-Cr perovskites were prepared, characterized, tested in comparison with the reference LaCrO3. The progressive increase in the Li content of the catalysts induces an increase in the catalytic activity owing to the enhancement of the amount of weakly chemisorbed oxygen O-species, key players in the soot oxidation mechanism. However, beyond 20% Cr substitution with Li, part of this latter metal was segregated as LiCrO2. The best single-phase catalyst (La0.8Cr0.8Li0.2O3) was already active well below 350°C. Catalytic traps were prepared by in situ combustion synthesis within cordierite and SiC wall-flow filters on the basis of the above catalysts and tested on real diesel exhaust gases in an engine bench, fully confirming the encouraging results obtained on powder catalysts.

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.

Non-intrusive diagnostic techniques based on broadband (190-550 nm) extinction and scattering spectroscopy were applied at undiluted exhaust Common- Rail (CR) diesel engine in real time. The influence of load and Exhaust Gas Recirculation (EGR) on soot mass concentration, size distribution of emitted particles and NO concentration was analyzed. NO concentration was evaluated by ""in-situ"" ultraviolet-visible absorption measurements and compared with those obtained by conventional analyzer. The extinction and scattering spectra were compared with those evaluated by the Lorenz-Mie model for spherical particles in order to retrieve the size, the number concentration of the emitted particles and particulate mass. The optical measurements showed that new generation diesel engines, in spite of a drastic reduction of the exhaust mass concentration, caused the emission in the atmosphere of high number concentration of carbonaceous nanoparticles.

The present paper reports the results of an experimental investigation carried out on a four-stroke single- cylinder D.I. diesel engine (100 x 95mm bore x stroke) with the aim to evaluate the effects of a four-lobe square combustion chamber on the gaseous and particulate emissions. Fluid-dynamic behaviour of the axisymmetric toroidal and four-lobe square chambers was investigated by Laser Doppler Anemometry. Engine tests at 2000 and 3000 rpm for different start of combustion (SOC) and A/F ratio are reported. Particulate, HC and NOx emission index measured under different operating conditions are given. In addition, the volatile content of the particulates produced from the two chambers at various engine operative conditions was measured by thermogravimetric analysis (TGA). Finally, the catalytic activity of a metal-oxide-based catalyst in the combustion of particulate was also evaluated by TGA.