Effect of engine parameters on the mixture distribution, performance and emission characteristics of a gasoline direct injection engine with baffles - A numerical analysis

Baffles inside the combustion chamber of internal combustion (IC) engines improve in-cylinder mixture distribution, performance, and emission characteristics. However, the effect of engine operating parameters on these aspects of the engine with baffles (EWB) remains underexplored. In this study, using computational fluid dynamics (CFD), the effects of fuel injection pressure (FIP), engine speed and load in a spray-guided, gasoline direct injection engine (GDI) are analysed and compared with the conventional engine. For the analysis, injection pressures of 30, 50, 80, and 120 bar; engine speeds of 1000, 2000, and 3000 rev/min.; and overall equivalence ratios of 0.7, 0.9, and 1.2 are considered, keeping the fuel injection timing constant. Results show that, EWB outperforms the conventional engine under various conditions considered. Also, it is found that the performance of EWB at an FIP of 30 bar is comparable to that of the base engine at an FIP of 80 bar. Additionally, the EWB exhibits better thermal efficiency across all the engine speeds and load conditions. Moreover, the HC and CO emissions of the EWB are found to be lower in most engine operating conditions. However, NOx emissions are marginally higher than those of the base engine.