Vehicular Experience with Additives for Regeneration of Ceramic Diesel Filters

The regeneration behaviour of the ceramic diesel particulate filter is investigated. It is found that regeneration of the vaporizable components absorbed by the soot is promoted. The addition of manganese leads to a second conversion maximum. When additives are used, ceramic filters pass through a “running-in” phase. As regards Mn emissions, emissions of Mn oxides of all valency stages as well as Mn-^SO₄may occur. These emissions amount to a maximum of 2.2 µg Mn/mile. Dispersion calculations for worst case situations have shown, that the maximum Mn-immission caused by using manganese fuel additives is still within the level of present immissions.

Families of characteristics are shown for emissions of the diesel particulate filter for particles and NO_x. By using filters with higher efficiency the particulate emissions may fall below 0,08g/miie. The particulate filter and the additive metering system have proved satisfactory in a field test in the US.