In the first category, a significant fuel consumption
penalty must be fore seen to supply the additional
energy required for regular thermal regeneration
during city driving. Catalytic regeneration, on the
other hand, is based on the use of catalysts to
achieve the onset of regeneration at significantly
lower temperatures. The catalyst may impregnate the
porous ceramic wall or be used as a fuel additive,
which is emitted and accumulated in the filter together
with the particulate. The use of catalysts is critical to
the design of a successful diesel filter system, because
it overcomes both problems mentioned above: namely
that of minimizing back pressure levels and that of
sustaining regeneration at low temperatures
The use of some catalytic fuel additives results in
regeneration temperatures as low as 350°C, although
stochastic regeneration may be observed even down
to 200°C for high filter loadings.