First diesel particulate filter from Rüsselsheim

Shortly after the first German brands BMW and Mercedes diesel
particulate filters have made diesel engines for their prospective
move, even now after the Rüsselsheim. The German GM subsidiary will
also introduce the public at the IAA 2003 in Frankfurt, their first,
newly developed and maintenance-free diesel particulate filter system
(DPF).

It requires no fuel additives and, according to data from Opel also
avoid other drawbacks of previous systems. With the help of a new
regeneration process were fuel consumption, CO2 emissions and power
almost at the same level as in operation without a filter. Mass
production is scheduled for early 2004 in the Vectra and the Signum
line with the new 1.9 CDTI Ecotec engine.

In addition to soot particles are also the levels of hydrocarbon (HC)
and carbon monoxide (CO) emissions by the interaction of a
close-effectively reduce pros and an underfloor catalyst. The new
diesel particulate filter consists of a honeycomb-shaped ceramic solid
silicon carbide. It is crossed by microscopic channels. Happens, the
exhaust stream, the channel walls, the carbon black particles collect
on the surface.

To avoid clogging of the filter, which must be burned particles
deposited on time. In the past, the developers decided here often for
the addition of a fuel additive to reduce the ignition temperature. In
this type of regeneration process was initiated. The engineers of the
GM Powertrain and Opel jointly developed diesel particulate filter
technology, but dispenses such additives. To raise the exhaust
temperature of the diesel engine for the combustion process in the
filter to the required ignition temperature of 600 ° C, this system
serve a noble metal coating of the filter substrate and targeted
multiple injections. This requires the injection system to be very
flexible, ideally in each engine load range. The system will
eventually not only work at full capacity, but also in the "cold", is
optimal.

This is the regeneration, adapted to the respective driving behavior
in discontinuous intervals, and the combustion of the soot particles
deposited - ie the injection of fuel - will take place only if a
suitably large back pressure is caused by the loading in the filter.
In the context of the DPF unit contains pressure and temperature
sensors that control the entire process from the driver unnoticed.

Besides the close-coupled "Start-Kat 'of the particle filter is an
oxidation catalyst upstream of the oxidized using the air oxygen
compounds such as HC and CO in the diesel exhaust. The nitrogen oxide
emissions could reduce the Opel engineers according to their own
information through in-engine measures alone under the limits of the
Euro-4 standard. The only mandatory from 2006 for vehicle
registrations standard requires a halving of the current limits for
particulate and nitrogen oxide emissions from diesel engines.