Abstract This study evaluates the influence of progressive dimethyl carbonate (DMC) blending on combustion characteristics, engine performance, and regulated gaseous emissions in a compression ignition engine. It further examines whether ignition enhancement using 2‐ethylhexyl nitrate (EHN) can restore combustion efficiency at elevated oxygenation levels. Four fuels were prepared and tested at constant speed: neat diesel (D100), 10% DMC (D90DMC10), 20% DMC (D80DMC20), and 20% DMC with 2% EHN (D78DMC20EHN2). The results show that increasing DMC concentration from 10% to 20% reduced nitrogen oxides (NOx) by 6.0% due to evaporative cooling and delayed combustion phasing. However, higher oxygenation prolonged ignition delay and shifted peak pressure away from top dead center. Brake specific fuel consumption (BSFC) increased by 19.8%, and brake thermal efficiency (BTE) decreased by 6.1% at maximum load. Hydrocarbon (HC) and carbon monoxide (CO) emissions increased at low load because of reduced oxidation temperature. The addition of 2% EHN shortened ignition delay and restored combustion timing. BTE improved by 4.1%, and BSFC decreased by 15.4% compared with the 20% DMC blend. HC and CO emissions were reduced, while NOx remained below diesel levels. These findings confirm that progressive oxygenation improves emission behavior but affects combustion stability at higher blending levels. Controlled cetane enhancement effectively compensates for this limitation. The proposed staged strategy provides a practical framework for optimizing oxygenated diesel blends without engine modification.
Vellaiyan et al. (Mon,) studied this question.