Effects of ASR on combustion performance, GHG emissions and economic efficiency of ammonia/biodiesel dual-fuel low-carbon engine

Ammonia, as a green and carbon-free hydrogen energy carrier, plays an important role in clean energy applications, while the addition of biofuel can also reduce the carbon footprint of engine. Therefore, the ammonia/biodiesel dual-fuel (ABDF) combustion mode is a new green and low-carbon combustion technology. In this study, the experimental investigation of ABDF engine performance at different ammonia substitution ratios (ASRs) and loads based on a modified four-cylinder common-rail engine has been conducted. The results indicate that the peak in-cylinder pressure decreased and occurred earlier as ASR increased, and the combustion duration increased with load, limited by ammonia inert combustion and inhibition. With the increase of ASR, the IMEP decreased, while the coefficient of variation increased. In addition, ammonia exacerbated incomplete combustion, leading to a rise in NH₃, CO and HC emissions. The reduction in NOx and GHG emissions reached the maximum at ASR = 60 %. Since life cycle assessment (LCA) of ammonia is higher than biodiesel, the increase in ASR increased LCA by 17.1 % at 75 % load. In energy balance, unburned losses increased with increasing ASR by 5.9 %, 6.0 % and 2.5 % at ASR = 60 %. The energy consumption and equivalent diesel consumption decreased with increasing ASR, resulting in more economical cost.