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Earlier work [1] shows that kinetics of Diesel soot oxidation is different from that of ethylene diffusion flame soot oxidation [2], possibly due to metals from lube oil. This study investigates the influence of metals on soot oxidation and the exhaust particle emissions using lube oil dosed fuel (2 % by volume). This method does not simulate normal lube oil consumption, but is used as a means of adding metals to particles for oxidation studies. This study also provides insight into the effect of systems that mix lube oil with fuel to minimize oil change service. The HTO-TDMA (High Temperature Oxidation-Tandem Differential Mobility Analyzer) technique [1] was used to measure the surface specific oxidation rate of Diesel particles over the temperature range 500-750 °C. Diesel particles sampled from the exhaust stream of a Diesel engine were size segregated by differential mobility and oxidized in situ in air in a heated flow tube of known residence time and temperature profile.

This study examines the effect of a ceramic particle trap and a manganese fuel additive on the mutagenic activity and chemical composition of diesel exhaust particulate matter from a heavy-duty mining engine. Particles were collected by dilution tunnel sampling from a 4-cylinder, Caterpillar 3304, naturally-aspirated, indirect-injection engine operated at six steady-state conditions. Depending on engine load and speed the ceramic particle trap reduced the following emissions: particulate matter, 80 – 94%; soluble organic fraction (SOF), 83 – 95%; 1-nitropyrene, 94 – 96%; and SOF mutagencity, 72% (cycle-weighted average). When the Mn fuel additive was used without a ceramic particle trap the total cycle mutagenic activity emitted increased 7-fold, in part, due to elevated emissions of 1-nitropyrene.