The CFD analysis of influence the start of fuel injection (SOI) on combustion parameters and exhaust gas composition of the marine 4-stroke engine

Abstract

The paper presents a theoretical analysis of the impact of injection timing on the parameters of the combustion process and the com-position of exhaust gas from a 4-stroke engine designed to shipbuilding. The analysis was carried out based on a three-dimensional multi-zone model of the combustion process. This model has been prepared on the basis of properties of the research facility. The input data to the model were obtained through laboratory tests. Results of calculations showed that the change of the start of injection angle (SOI) from the value of 14 degrees before TDC to 22 degrees before TDC results in changes in the combustion rate and thus an increase in the temperature of the combustion process as well as the increase of nitric oxides fraction in the exhaust gas. Simultaneously the maximum combustion pressure increases also.

Simulation tests of selected gas flow parameters through combustion engine valves

“…In CFD methods, the problem is the interpretation of results, because the computer "counts everything", unfortunately not always in accordance with the physical characteristics of the phenomenon. This requires a skillful interpretation of the results [4,16,23].…”