Study of the Combustion Process of a Homogeneous Charge Compression Ignition (HCCI) Engine and a Partially Premixed Combustion (PPC) Mode of a Compression Ignition Engine Using Natural Gas as an Alternative Fuel

In order to investigate a viable approach to achieving high efficiencies and low nitrogen oxide (NOX) emissions, this paper presents the application of a homogeneous charge compression ignition (HCCI) engine and the partially premixed combustion (PPC) mode applied to a heavy diesel engine. The effect of carbon dioxide (CO2) fraction on combustion parameters was analyzed and discussed in detail. For this purpose, on the one hand, ANSYS CHEMKIN-Pro software was used to perform simulations of a closed homogeneous reactor under conditions relevant to HCCI engines, and on the other hand, ANSYS-Fluent software was used by adding a CO2 fraction varying from 20% to 58% to methane fuel to study 2D flow simulation by applying a PPC combustion mode to predict the distribution of various output parameters such as in-cylinder temperature, in-cylinder pressure and emissions. In comparison with the two presented models, it was found that the HCCI engine showed a lower NOX level than the PPC mode and this was due to the lower in-cylinder temperature in the HCCI engine.