Direct injection in internal combustion engines is often realized with a multi hole injector which forms a spray pattern consisting of multiple jets with a small distance between their origin. This leads to an interaction of adjacent spray jets. The spray characteristic is significantly influenced by this interaction, and can considerably change the fuel evaporation and with it the emission behavior with varying number of holes or hole nozzle geometry [8]. Experimental investigations, especially if a good optical access to a single jet is necessary, often needs to use a comparable injector with a reduced number of holes. In addition to that, 3D-CFD simulation models can also use a reduction of spray jet number for a partial consideration of fuel mixture to reduce the computing time. For these cases a determination of the correlation between spray formation and reduced nozzle holes is important. In this work the spray patterns of an original 6-hole gasoline DI-injector and, after closing of 5 holes, the resulting 1-hole injector were compared. The fuel mass flow through one hole can change due to a change of hydrodynamic effects inside the nozzle and leads to a correcting factor for the injecting time, to get comparable fuel mass flows. The penetration depth, droplet speed, size and spatial distribution were measured. Additional investigations of the influence of the fuel pressure and fuel temperature were carried out.

This content is only available via PDF.
You do not currently have access to this content.