Experimental Study of DPF Loading and Incomplete Regeneration

It is well known that diesel particulate filters can be subjected to incomplete regeneration which can lead to DFP failure when a severe regeneration follows several partial regenerations. The following study concentrates on C-DPF (Catalyzed Diesel Particulate Filter) filters made of R-SiC (Re-crystallized Silicon Carbide) from Saint-Gobain and aims at studying the spatial soot distribution in the filter as a function of soot loading and regeneration efficiency.

The soot distribution is deduced from a radial velocity profile at the rear of the filter which is measured using a specific test bench. In this work, an experimental protocol is designed to produce a controlled partial regeneration. This protocol allows the desired regeneration efficiency to be obtained. It can be observed that the better the regeneration efficiency is, the more the radial distribution of remaining soot in the filter is homogeneous. Consequently, regeneration is more efficient where the filter is more loaded. This result shows that partial regeneration in the case of a controlled regeneration tends to homogenize the distribution of soot in the radial direction and thus not to concentrate soot which is not regenerated. Moreover, it is observed that the correlation between the mean velocity and the remaining soot mass after partial regeneration is very different from that obtained for the mechanism of soot loading.

This experimental study is extended with an investigation of the longitudinal soot deposition which demonstrates the density difference between the soot deposited during loading and the soot deposited during regeneration.