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Experimental work was carried out on a small displacement Euro 5 automotive diesel engine alternatively fuelled with ultra low sulphur diesel (ULSD) and with two blends (30% vol.) of ULSD and of two different fatty acid methyl esters (FAME) obtained from both rapeseed methyl ester (RME) and jatropha methyl ester (JME) in order to evaluate the effects of different fuel compositions on particle number (PN) emissions. Particulate matter (PM) emissions for each fuel were characterized in terms of number and mass size distributions by means of two stage dilutions system coupled with a scanning mobility particle sizer (SMPS). Measurements were performed at three different sampling points along the exhaust system: at engine-out, downstream of the diesel oxidation catalyst (DOC) and downstream of the diesel particulate filter (DPF). Thus, it was possible to evaluate both the effects of combustion and after-treatment efficiencies on each of the tested fuels.

This paper focuses on measuring particle emissions of a representative light-duty diesel vehicle equipped with different engine exhaust aftertreatment in close-coupled position, including one designed to meet the upcoming Euro 6 emission standards. The latter combines a lean NOx trap (LNT) and a diesel particulate filter (DPF) in series to simultaneously reduce NOx and PM. Particle Matter (PM) and particle number emissions are measured throughout testing procedure and instrumentation which are compliant with the UN-ECE Regulation 83 proposals. Specifically measuring devices for particle number emissions, provided by two different suppliers, are alternatively used. No significant differences are observed due to the different system employed. On the other hand particle size distributions are measured by means of a specific experimental set-up including a two stage dilution system and an electrical low pressure impactor (ELPI).

The effects of using blended renewable diesel fuel (30% vol.), obtained from Rapeseed Methyl Ester (RME) and Hydrotreated Vegetable Oil (HVO), in a Euro 5 small displacement passenger car diesel engine have been evaluated in this paper. The hydraulic behavior of the common rail injection system was verified in terms of injected volume and injection rate with both RME and HVO blends fuelling in comparison with commercial diesel. Further, the spray obtained with RME B30 was analyzed and compared with diesel in terms of global shape and penetration, to investigate the potential differences in the air-fuel mixing process. Then, the impact of a biofuel blend usage on engine performance at full load was first analyzed, adopting the same reference calibration for all the tested fuels.