Cold-start particulate and hydrocarbon performance of a polished crown piston against a standard piston fitted to a two-litre turbo-charged direct injection diesel engine

摘要

The piston crown surface finish of a standard piston is typically 1.1μm Ra, this has been improved to 0.1μm Ra. The emissions of particulates and hydrocarbons have been collected and compared for the two piston types in four 30 second periods.The particulate emission levels between the two piston types remained similar but the polished crown piston produced higher hydrocarbon emissions. Further analysis of the gas phase hydrocarbon emissions showed significant differences in the range ofalkanes produced and when they were produced. The paper concludes with possible reasons why this occurred.