Experimental study on ammonia-diesel co-combustion in a dual-fuel compression ignition engine

Ammonia, as a carbon-free renewable fuel and a potential hydrogen carrier, is gaining increasing interest in addressing greenhouse gas emissions in industrial applications and transportation. This paper presents experimental studies on the co-combustion of ammonia with diesel fuel in a single-cylinder industrial compression ignition engine operating in dual-fuel mode. The energy share of ammonia ranged from 0 to 60%. Increasing the proportion of ammonia compared to diesel fuel in the compression ignition engine leads to a change in the combustion process character, increasing the kinetic combustion phase at the expense of diffusive combustion. However, it does not result in an increase in the peak pressure rise (PPR) beyond the permissible value of 1 MPa/deg for piston engines. It increases ignition delay and shortens the combustion duration, while also increasing thermal efficiency and decreasing specific energy consumption. An increase in the NH3 share results in a decrease in combustion efficiency, a reduction in unit emissions of NO, CO2, and soot, and an increase in CO emissions. Beyond 42% ammonia share, it reduces unit THC emissions. At a 42% ammonia share, the dual-fuel engine achieves the highest indicated thermal efficiency (ITE), lowest specific energy consumption (SEC), shortest combustion duration, and lowest unit soot emissions. © 2024 Energy Institute