Combustion, gaseous emissions and PM characteristics of Di-Methyl Carbonate (DMC)-gasoline blend on Gasoline Direct Injection (GDI) engine

The higher level of particle emissions of Gasoline Direct Injection (GDI) engines with respect to their counterpart port fuel injection engines motivated the introduction of legislative measures to limit their number in addition to the particulate matter (PM) mass. This study presents the impact on pollutant emissions of a potentially suitable oxygenated component, Di-Methyl Carbonate (DMC), as a supplement to gasoline fuel. Exhaust PM was characterised with Thermogravimetric Analysis (TGA) to understand its oxidation behaviour and composition, Transmission Electron Microscopy (TEM) to study the morphological characteristics of its agglomerate and Raman Spectroscopy (RAMAN) to analyse the particle nano-structure. Engine studied of an 8% v/v DMC-gasoline fuel blend (D8) show similar combustion characteristics and fuel economy compared to gasoline. The combustion of DMC fuel blend reduced total unburnt hydrocarbon (THC) by approximately 30% and the number of PM emissions by 60%. Characterisation of particles formed by D8 demonstrated morphological and nano-structural alterations including a 10% reduction in primary particle size, leading to greater particles oxidation reactivity. The oxidation of particles emitted from the combustion of D8 started 15 °C earlier when compared to particles emitted from the gasoline combustion.