Spray Development Process Utilizing a Multi-Hole GDI Injector with Different Spray Hole Lengths and Step Hole Diameters

Abstract

This study focused on the spray development process via spray visualization experiment using different nozzle shape. Specifically, the spray penetration and initial spray angle were determined by high-speed camera and Long distance microscope (LDM) visualization system. Additionally, a sheet beam Nd-YAG laser was used to obtain the spray pattern. The experimental results showed that an injector with a step hole of smaller diameter has a narrower spray angle at the initial injection stage and longer spray penetration compared to an injector with a step hole of larger diameter. In addition, spray penetration was greater for a shorter spray hole length. These results demonstrate that the structure of the step and spray hole for a multi-hole Gasoline direct injection (GDI) injector is an important parameter in the spray development process. Because the air flow path could be changed according to the spray and step hole dimensions. Moreover, CFD simulation was conducted by Star-CCM+ 13.06 in order to find out about air recirculation phenomenon.