Identifying Unregulated Emissions from Conventional Diesel Self-Ignition and PPCI Marine Engines at Full Load Conditions

Abstract

A study on unregulated emissions of a conventional diesel self-ignition and partial premixed compression ignition (PPCI) marine engine at full load condition was performed, respectively. In this work, PPCI was realized in a marine engine by blending 15% diesel with 85% light hydrocarbons (LHC). Gas chromatography-mass spectrometry (GC-MS) was used to detect and identify unregulated emissions, and the chemical formula and peak area of representative species were obtained. Furthermore, the unregulated emissions were classified and semi-quantitatively analyzed. The results show that the maximum in-cylinder pressure of PPCI is almost 11 bar lower than that of conventional diesel combustion, and the crank angle at that moment is also delayed by 2 °CA. Compared to conventional diesel combustion, the maximum pressure rise rate of PPCI is reduced by 3.5%, while the maximum heat release rate of PPCI increases by 23.5%. Further, PPCI produces fewer species in unregulated emissions, and their chemical formula are less complex than that of conventional diesel combustion. Compared to conventional diesel combustion, the relative concentration of alkane and organic components in PPCI decreases significantly, while ketone and ester increase.