Abstract
It is well known that diesel particulate filters (DPF) can be subjected to incomplete regeneration which can lead to DFP failure when a severe regeneration follows many partial regenerations. The following study concentrates on C-DPF (Catalysed Diesel Particulate Filter) filters made of R-SiC (Recrystallized Silicon Carbide) from Saint-Gobain and aims at studying the soot distribution in the filter as a function of regeneration efficiency. The soot distribution is deduced from a radial velocity profile using a specific test bench.
First, an experimental protocol has been designed to produce a controlled partial regeneration. This protocol allows us to obtain the desired regeneration efficiency. To measure the velocity profiles at the filter outlet a specific test bench has been designed and built. We use a propeller anemometer with a diameter of 9 mm.
Test results do not show a direct linear correlation between the pressure drop efficiency (ratio of the total pressure loss of the filter before regeneration on the pressure loss after regeneration) and the mass efficiency (ratio of the soot mass after regeneration on the soot mass before regeneration) during partial regenerations. On the contrary a very good linear correlation between the mean velocity and the regeneration efficiency has been observed.
Moreover, it could also be observed that more the regeneration efficiency increases and more the radial distribution of remaining soot in the filter is uniform. This result shows that partial regeneration in the case of a controlled regeneration tends to have a uniform distribution of soot in the radial direction and thus to not concentrate soot which are not regenerated.
Then, we have seen that the correlation between the mean velocity and the remaining soot after partial regeneration is different from that obtained during loading. Thus, to load a filter completely then to empty it partially does not give the same result as to load it partially. We think that the regeneration that we used modifies the organization of soot inside the filter.
Keywords:Diesel particulate filter, partial regeneration, loading, velocity profile, soot.