Fuel Vaporizer: Alternative Solution for DPF Regeneration 2010-01-0561
Current emission standards for diesel passenger cars in Europe
and the US require the use of diesel particulate filters (DPF). For
optimal engine performance the accumulated soot on the filter has
to be removed periodically at elevated exhaust gas temperature of
600-650\,DC. Since many driving conditions do not allow such
exhaust gas temperature additional measures have to be applied to
increase the temperature in the exhaust.
Post-injection of diesel fuel in the combustion chamber is the
more common solution used to increase the exhaust temperature for
particulate filter regeneration. Oil dilution is one of the
drawbacks of regeneration by post-injection.
The use of a fuel vaporizer is another option to increase the
exhaust temperature by introducing fuel in vapor form into the
exhaust system. The vaporizer can be located in front of the
DOC/DPF either in a close coupled position to the engine or in an
underfloor position. The vaporized hydrocarbons (HC) are burnt on
the diesel oxidation catalyst (DOC). Energy is released by
exothermal chemical reactions and the required regeneration
temperature is obtained in front of the DPF.
This paper discusses the impact of different exhaust system
designs and different fuel vaporizer locations on the performance
of such technology. The performance is analyzed relative to uniform
temperature distribution and HC-slip. The results of these
measurements are used to discuss how a fuel vaporizer can be used
to develop an optimized strategy for DPF regeneration in
combination with post-injection.