Optical Characterization of Nanoparticles from an Advanced Common-Rail Diesel Engine

This paper explores the effects of fuel injection pressure, charge dilution (EGR) and fuel-air mixing (swirl) on the particulate matter emissions at the exhaust of a state-ofthe- art DI diesel engine. The engine is a single cylinder prototype engine, derived from the Euro IV version of FIAT 1.9 JTD M-Jet 16V. A test point was selected, corresponding to a low load condition in the European emission test schedule for light duty cars. An unconventional diesel combustion regime, aimed to get lower flame temperatures and overcome the NOx-soot trade off, has been also investigated. A physical characterization of carbonaceous particulate has been carried out at the engine exhaust by means of optical diagnostic techniques. The size of soot primary particles has been inferred by means of time-resolved laser induced incandescence, whilst the mean size of soot aggregates has been measured using light scattering methods.