Spray and atomization characterization of a multi-hole GDI injector

The purpose of this study is to investigate a behavior of spray development and atomization characteristics of a multi-hole gasoline direct injection (GDI) injector. For this experiment, a two-dimensional phase Doppler particle analyzer system was used to measure droplet diameter and velocity simultaneously. To investigate overall atomization characteristics of GDI spray, measurements have been performed on a single jet and center region of spray. Results showed that the SMD at the region of single jet tends to be larger than that of center region of spray. However, approaching the end of injection period, an increase in droplet diameter of center region of spray was observed. This can be considered as the effect of droplet coalescence due to low velocity and large number of droplet. The velocity of single jet maintained a constant velocity of 60m/s during injection period. After the end of injection period, however, a great reduction in the velocity was observed