Light intensity and image visualization of GDI injector sprays according to nozzle hole arrangements

The light intensity measurement and image visualization of multi-hole injection spray due to different hole arrangements and hole numbers were investigated. The light intensities and behavior characteristics of the GDI spray were analyzed through the axial and diagonal spray penetration, cone angle, and spray area from the spray images by using the image visualization system and image analysis system. The atomization performance of GDI injectors was analyzed by the local and overall Sauter mean diameter (SMD) measurement.It is revealed that the higher injection pressure shows higher light intensity levels due to the strong vortices and collision by a high injection pressure. The light intensity level at the outer and end region of the spray shows lower value compared to that at the center spray region. In all of test injectors, the increased injection pressure leads to the decrease of the droplet size distribution in the initial spray. But, there is little difference of the droplet size at low and high injection pressure in middle and latter period after the injection. The overall SMD of GDI injectors showed from 14 to 23.14 μm.