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Porous honeycombs filters have been widely used for diesel particulates filtration in passenger cars applications. In all current DPF applications, filter lifetime and design are dictated by the need to store non combustible ash generated at the exhaust. Therefore, improving the ash storage capacity of a filter appears as a major step towards the development of maintenance free DPF systems. This paper describes a new filter design that was developed to optimize ash storage volume. Numerical simulations and roller bench tests have been performed in order to compare the performances of this new filter to commercial honeycomb filters.

Recrystallized Silicon carbide (R-SiC) honeycombs have been widely used over the last couple of years as filtration media for diesel particulates filtration in passenger cars applications. Although such filters are very reliable thanks to SiC good properties and smart designs, existing devices can still be improved. This paper describes several new features developed for R-SiC honeycomb filters in order to increase their durability and reduce their cost. Durability improvements can be obtained through the optimization of different filter properties such as thermo-mechanical resistance and thermal diffusivity. Specific tests have been performed in order to optimize new R-SiC filters.

This paper describes mid-load experimental tests combining massive EGR rates and multiple injection strategies. Influence of very high EGR rates on combustion has been reviewed, and a response-surface-modeling tool has been used to present main results. Outputs from this empirical model did highlight a dramatic soot increase when oxygen concentration is reduced. The empirical model based on experimental results model was also used to define more precisely the EGR rate needed to reach US 2010 NOx target. This EGR rate being defined, some investigation has been made on dual-injection strategies combining a main injection with an early pilot injection. Both quantity and timing of pilot injection were varied, and experimental results showed large benefits of this strategy to reduce soot emissions without significant increase of NOx emissions or fuel consumption. Better results were also experienced with the addition of a close post-injection.