Effect of fuel injector nozzle hole diameter on emissions of CAT 3401 diesel engine using CONVERGETM CFD

Abstract

Variation of fuel injector nozzle hole is on engine emission and performance is evaluated in present article. Simulation is carried out on caterpillar 3401 diesel engine is using CONVERGE CFD code. A 60° sector model with SAGE combustion model was considered to examine the four different nozzle hole diameters (0.230mm, 0.240mm, 0.250mm, 0.259mm and 0.270mm) and their effect on the engine performance, emissions and spray characteristics. The combustion results showed that nozzle hole diameter of 0.230mm contributed for maximum in-cylinder pressure and temperature due to enhancement in spray cone angle, atomization, and efficient air-fuel mixture. HC, CO, and soot Emissions were found to be decreased with the decrease in nozzle hole diameter, however, due to enhanced atomization and the overall increase in cylinder gas temperature, the NOx emissions were observed to increase for nozzle holes with smaller diameters. Droplet radius for 0.250mm, 0.259mm and 270 mm is found to be larger to the formation of lower jet velocities. Thus nozzle holes with smaller diameter tend to reduce the emissions with a penalty in NOx emission.