Statistical analysis of diesel fuel effects on particle number and mass emissions

Particle number concentration and particle matter emissions from an indirec t injection diesel light duty vehicle are statistically examined to reveal significant differences using eight nonoxygenate, one oxygenate, and the re ference fuel. All fuels are of very low sulfur (<43 ppmw) and aromatics (<2 3.7% vol.) concentration. Analysis of variance is applied on particle sampl es collected from raw exhaust by an Electrical Low Pressure Impactor and on filter measurements conducted in the dilution tunnel over the Urban and th e Extra Urban Driving Cycles. Statistically significant increase on both th e number and the mass of emitted particles is established with increasing s ulfur and aromatics content accompanied by a marginal increase of the mean particle size. Total number differs by similar to3 times and mass by simila r to 50% between the most and least refined of the fuels tested. Finally, u se of the oxygenate fuel provides a similar to 20% reduction of both the ma ss and the number over an equivalent, nonoxygenated fuel.