Abstract
Keywords - Particulate measurement, volatility, size distribution, OC/EC, v-TDMA.
Abstract - Measurements of exhaust gas particles from two different heavy-duty diesel vehicles on chassis dynamometer were done at two different steady state cases (idle and high load engine conditions), with two different qualities of diesel fuels. Dilution was done with either a rotating disc diluter or a conventional full flow dilution tunnel. The measuring system includes a volatility tandem DMA (v-TDMA) with a heated section, and a filter sampling set-up for post experiment analysis of organic and elemental carbon particulate matter collected on quartz filter. Results from the v-TDMA show a consistent trend in the amount of volatile material on particles to the fractionation of organic and elemental carbon mass based on the quartz filter analysis. In general, high load v-TDMA results show low volatilisation of the particulate matter, which is consistent with the low organic carbon content shown by filter analysis. The size distributions for these high load cases show a single mode in the accumulation size range. The accumulation mode is regarded as mostly containing carbon agglomerates, which is consistent with the high carbon content shown by the total carbon analysis. On the other hand, results from tests at idle conditions show a smaller accumulation mode as well as a pronounced nucleation mode. The tests at idle have low total carbon content, and higher fraction of organic carbon. The presence of more volatile material on the particles was seen in the v-TDMA results for small particles as a shift of the peaks in the size distribution towards smaller size after heat treatment.