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Different Diesel Particle Filters (DPF)*) were tested on a 2-Stroke Detroit-Diesel bus engine 6V 92 TA. The investigations focused on soot burden and regeneration of the DPF with special filter materials. Also examined was promoting the regeneration by: throttling, additive (FBC), oxidation catalytic converter upstream of DPF and the catalytic coating of the filter material. The metrics were the particulate matter emission, its composition and the nanoparticles. The most important results are: The average SOF content in the engine exhaust particulate matter is 77.6 % and the majority of it is emitted as bigger droplets The wire-mesh filter catalyst (WFC) - a novel emission reduction technology -substantially curtails the SOF and PM. WFC traps and oxidizes the oil droplets and produces a “dry” soot. This can be very advantageous for the DPF downstream of WFC. (WFC can be also very interesting for 2-S gasoline engines).

NO₂ is much more toxic than NO. The average proportion of NO₂ in exhaust gases of vehicles increases significantly due to the use of oxidation catalysts and catalytic coatings in the exhaust gas systems during the last decades combined with generalization of using low sulfur fuels. Diesel oxidation catalysts (DOC) and Pt-containing DPF coatings are widely used to support the regeneration of particle filters, being a source of strongly increased production of NO₂. The present work shows some examples and summarizes the experiences in this matter performed at the Laboratories for IC-Engines & Exhaust Emissions Control (AFHB) of the University of Applied Sciences Biel-Bienne, Switzerland, during some research activities on engine dynamometers in the years 2010-2012.

The progressing exhaust gas legislation for on- and off-road vehicles includes gradually the nanoparticle count limits. The invisible nanoparticles from different emission sources penetrate like a gas into the living organisms and may cause several health hazards. The present paper shows some results of a modern chain saw with & without oxidation catalyst, with Alkylate fuel and with different lube oils. The measurements focused specially on particulate emissions. Particulates were analysed by means of gravimetry (PM) and granulometry SMPS (PN). In this way the reduction potentials with application of the best materials (fuel, lube oil, ox-cat.) were indicated. It has been shown that the particle mass (PM) and the particle numbers (PN), which both consisting almost exclusively of unburned lube-oil, can attain quite high values, but can be influenced by the lube oil quality and can be considerably reduced with an oxidation catalyst.