| The increasingly stringent particulate regulations for Diesel engines require wide studies about the effect of engine design parameters, operating conditions and fuel characteristics on particulate emissions and composition. Additionally, the size distribution of particulate aerosols are receiving growing attention due to the effect of some of the new engine technologies to generate smaller particles, which increase their hazardous effect on humans. This thesis is focused on the different methodologies to chemically and morphologically analyse the particulate matter emitted by a typical European passenger car Diesel under typical urban and extra-urban road conditions, an with different fuels of present interest, as biofuels from sunflower and cardoon oils, emulsion with water and conventional fuels with different sulphur and aromatics specifications. In particular, the methodologies for engine test definition, particulate matter collection with a mini-tunnel, extraction of the soluble organic fraction, chemical analysis of both the soluble and insoluble fractions, determination of proportion fuel- and lubricant-oil derived hydrocarbons, and scanning electron microscopy and image processing of particulate matter collecting in the filters, are analysed and described in this thesis. Moreover, smoke and total hydrocarbon were measured during the particulate collection tests. The results from chemical analysis of the particles and the comparison with soot (measured as opacity smoke) and hydrocarbons emissions make it possible on the one side to study the relative hydrocarbon adsorption on the soot particles and on the other side to propose a correlation to estimate the particulate Diesel emissions using simple measures under undiluted and hot conditions. Finally some of the effects that the tested fuels and engine operating modes have on the particulate emissions and its characteristics are discussed using the results predicted by a neural network. |
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