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Diesel particle filters (DPFs) efficiently eliminate soot, fuel-, and oil-ash emissions of diesel engines, but little data are available with respect to long term aging or deterioration effects of DPFs under real world operating conditions. Aging of wash coat- and catalyst-materials, catalyst poisoning, ash sintering, adsorption and long lasting storage of semi- or non-volatile substances can take place, which over time may influence filtration and conversion properties of DPFs. Herein we report to what extent DPF aging may affect particle filtration characteristics. We compared particle number concentrations (PN), and particle mass (PM) emissions after a 2000 operating hours endurance test (VFT2). Such a controlled field test is required by VERT verification procedures, which lately were published as a national standard (SNR 277205).

Due to the limited energy resources as well as due to increasing CO2-emissions the importance of alternative- and biogene fuels increases continuously. Investigations of the engine operation were performed on a latest technology Liebherr engine for construction machines, which was operated using crude rapseed oil (ROR), rapseed methyl ester (RME) and synthetic Gas-To-Liquid fuel (GTL) without any change of ECU setting. On this occasion the combustion diagnostics, behaviour of the injection system and the pollutant emissions, including the unlimited nano-particles were especially assessed. For injection (with this unit pumps system) it can be stated, that ROR and a little bit less RME shorten the injection lag and increase the maximum injection pressure. At higher engine load this causes the 50% heat release a little earlier (1-2°CA) and as consequence higher NOx and lower specific energy consumption.