The role of charge reactivity in ammonia/diesel dual fuel combustion in compression ignition engine

This study investigates the combustion characteristics of diesel -NH 3 -air mixture in compression ignition engine. Three different levels of ammonia energy ration (AER) were used for the investigation: 0 % AER (pure diesel), 30 % AER, and 50 % AER. Increasing AER leads to a rise in the initial peak of apparent heat release rate and promotes the prevalence of premixed combustion. Numerical simulations effectively capture the abrupt increase in maximum cylinder pressure (P max ) from 7.4 to 7.9 MPa as AER increases from 0 to 30 %. Additionally, raising AER from 0 to 30 % extends a high-temperature region externally in the squish zone, attributed to the higher knocking propensity of the 30 % AER premixed charge. The ammonia-assisted diesel accomplish advanced diesel direct injection timing (SOI D ) at both heavy and medium load conditions. Under light load conditions, an increase in ITE is observed for AER = 50 % as SOI D varies from-4 degrees CA to-10 degrees CA (ATDC). For medium and high load conditions, ITE monotonically increases with advancing SOI D . The maximum ITE of 44.5 % is achieved at SOI D =-12 degrees CA (ATDC) and AER = 30 %.