Gas+Particle Engine Emissions Data

Particulate and vapour phase emissions in the diluted exhaust of a light duty diesel engine designed for Euro 5 application have been sampled. The engine was operated in three modes, and samples were collected from exhaust without aftertreatment but also with aftertreatment by an exhaust catalyst and particle filter. The samples were analysed by 2-dimensional gas chromatography with Time-of-Flight mass spectral detection. The results show overall removal efficiencies for organic compound mass by the combination of oxidation catalyst and particle filter of 50%, 56% and 74% for the high speed/high load, low speed/low load and high speed/low load conditions respectively. The results are clearly indicative of substantial repartitioning of the particulate and vapour components within the abatement devices and show an apparently reduced efficiency for removal of high molecular weight alkanes under high speed/high load conditions relative to lower molecular weight compounds, although this may be due to alkane formation by thermocracking of other species. A notable feature is the presence of oxygenated compounds in the emissions which are not present in the fuel. These are increased under high speed/high load conditions and the results suggest formation in the aftertreatment devices as well as in the combustion process.