Composition and size of diesel particulate emissions from a commercial European engine tested with present and future fuels

摘要

The search for alternative fuels, such as methyl ester from vegetable oils or water-oil emulsions, has become even more pertinent in the current context of fossil fuel shortage, the diesel vehicle population explosion and the new environmental policies. In this paper, the results of experimental research on particulate emissions from a typical indirect injection (IDI) diesel engine running under five different operating conditions and tested with fourteen types of conventional and alternative fuel are reported. The chemical analysis of the emitted particulate matter showed, for example, that the total mass of particulate emissions decreases when using biofuels owing to a reduction in their insoluble fraction. Moreover, composition analysis made it possible to identify the hydrocarbons adsorbed on the soot surface, to quantify their proportion with respect to the total particulate mass and to distinguish between their origins. The results of surface analysis using scanning electron microscopy showed for all the fuels that the number of particles detected per filter surface increased with load. This analysis also showed the effect of some fuel specifications (aromatic and sulphur content) on certain parameters related to the particle size distribution obtained from the filter images.