Chemical/physical features of particulate emitted from a Heavy-Duty SI LPG engine

Road traffic emissions are one of the main sources of environmental pollutants affecting urban inhabitants. Investigation focused to develop systems and processes for the reduction of air pollutants is strongly addressed to achieve near zero emissions goal. In the field of internal combustion engines (ICE), the use of alternative fuels together with the adoption of innovative combustion concepts are possible routes to develop high efficient and low emission technologies. Fuel decarbonization and the utilization of gaseous fuels are two top-notch approaches for emission lowering (including CO2) and for suitable standard regulations settlement. The major pollutants emitted in engine exhaust gases are particulate matter (PM), CO2, nitrogen oxides (NOx), and, to a lower extent, unburned hydrocarbons. PM formation is usually linked to (even local) fuel-rich conditions establishing in some phases during the combustion process (i.e. high engine load conditions). In this study the performances of a heavy-duty SI gas engine fueled with LPG (propane > 98%) were investigated by sampling and evaluating the chemical, physical and morphological characteristics of the emitted PM (off-line), as well as the engine-out particle size distribution function (PSDF) and total number (PN) (on-line).