Reduction of the amount of soot particles emitted by diesel engines (diesel particles) during operation can make the use of diesel engines more attractive because of the considerably reduced environmental pollution. The use of soot filters in the exhaust system of diesel engines can lead to the retention of a considerable percentage of the soot particles present in the exhaust gas.
However, the fact that filters that appear to be suitable, especially filters consisting of ceramic threads or ceramic fiber packings, become clogged relatively rapidly, thus losing their filter effect, is problematic.
To regenerate such filters, it has been proposed that the soot particles located within the filter material be burned off with a burner. It has also been proposed that an oxidizing agent be sprayed into the filter in order to lower the ignition temperature of the soot.
Soot filters must be regenerated at certain intervals (determined in terms of hours of operation or the pressure rise of the exhaust gas flowing through). Since the regeneration process takes some time and it cannot be assumed that the engine would be stopped during this period, two diesel particle filters can be arranged in parallel, one of which is always connected in the path of the exhaust gas, while the other is being regenerated and is awaiting use after completion of the regeneration. In an attempt to keep the fuel consumption of an engine as low as possible, the output of the burners during the regeneration of diesel particle filters should also be kept low.