Title: The effect of diesel engine conditions on the size and morphology of soot particles

Authors: Magín Lapuerta, Rosario Ballesteros, Francisco J. Martos

Addresses: Escuela Tecnica Superior de Ingenieros Industriales, University of Castilla – La Mancha, Edificio Politecnico, Avda., Camilo Jose Cela, s/n 13071 Ciudad Real, Spain. ' Escuela Tecnica Superior de Ingenieros Industriales, University of Castilla – La Mancha, Edificio Politecnico, Avda., Camilo Jose Cela, s/n 13071 Ciudad Real, Spain. ' Escuela Tecnica Superior de Ingenieros Industriales, University of Malaga, Plaza del Ejido, s/n 29013 Malaga, Spain

Abstract: Soot agglomerates emitted by diesel engines are variable in size and morphology, both characteristics having important environmental implications. The main geometrical characteristics of soot emissions can be quantified by means of the size distribution and the fractal dimension, the latter being a measure of the particle irregularity. In this work, size distributions were obtained with a scanning mobility particle sizer connected to a partial-flow dilution mini-tunnel, while fractal dimensions were obtained from high resolution transmission electron microscope images of agglomerates collected by thermophoretic sampling. Both the mini-tunnel and the thermophoretic probe sampled from the same point in the exhaust line, where smoke opacity and gas temperature were also measured. The engine was tested under different engine speeds, air/fuel ratios and exhaust gas recirculation rates, to evaluate their independent effects on the morphology of the emitted particles. Finally, the obtained trends were combined to estimate the effect of real driving conditions in a modern automotive engine on the main morphological characteristics of the soot particles.

Keywords: diesel engines; fractal dimension; microscopy; soot agglomerates; soot particles; soot emissions; size distributions; morphology.

DOI: 10.1504/IJVD.2009.024972

International Journal of Vehicle Design, 2009 Vol.50 No.1/2/3/4, pp.91 - 106

Published online: 06 May 2009 *

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