Experimental study on the effect of combustion and emission performance of biodiesel–ammonia dual-fuel engine

To assist vessels in meeting the net-zero emission target set by the International Maritime Organization for 2050, this article investigates the emission and combustion characteristics of biodiesel–ammonia dual-fuel engines. This research investigates the impact of various ammonia mass ratios (AMRs, m%) at 0, 14.67%, 29.48%, 46.21%, 58.73%, and 82.72% on the combustion and emission performance of biodiesel–ammonia dual-fuel engines at fixed speed and load. The results show that the biodiesel–ammonia dual-fuel engine is capable of operating at a substantial AMR of 82.72%. In addition, as the AMR increased, the in-cylinder pressure and brake thermal efficiency decreased. The heat release rate peaked at 57.13% AMR. When compared to the only-biodiesel mode, NOx, CO2, and soot emissions are significantly reduced. CO2 and soot emissions decreased by 63.43% and 60%, respectively, at 82.72% AMR, while NOx emissions fell by 34.15% at 58.73% AMR. The emissions of N2O and unburned ammonia rose linearly as AMR increased. The increase in N2O did not counteract the substantial fall in CO2e. CO2e fell by 63.12% at 82.72% AMR, following a trend to similar CO2.