Particle Number and SizeEmissions from a Small DisplacementAutomotive Diesel Engine: Bioderived vs Conventional Fossil Fuels.

Experimental work has been carried out on a small displacementEuro 5 automotive diesel engine fueled alternatively with ultralowsulfur diesel (ULSD) and with two blends (30% vol) of ULSD, with twodifferent fatty acid methyl esters (FAME) obtained from rapeseed methylester (RME) and jatropha methyl ester (JME). The engine-out particulatematter (PM) emissions have been characterized in terms of number andmass size distributions; measurements were performed under differentengine operating conditions that are representative of the New EuropeanDriving Cycle (NEDC), including cold start of the engine. No significantdifferences were detected in the particle numbers (PN) for the differentfuels under steady-state operating conditions, while a moderate reductionin particle mass size distribution was observed for the biofuel blends.The effects on PN emissions due to shifts in the engine operatingpoints on the calibration maps, caused by the different fuel characteristics,have been shown to be significantly larger than the effects due tothe different combustion characteristics of the biofuel blends, thushighlighting the need for a specific adjustment of the engine calibration. [ABSTRACT FROM AUTHOR]