Paper ID ICLASS06-074 EVALUATION OF IN-CYLINDER FLOW STRUCTURES AND GDI SPRAY PROPAGATION OVER A RANGE OF ENGINE SPEEDS AND INJECTION TIMING

The in-cylinder flow field during the latter half of the intake stroke in a single cylinder optical engine operating at 750, 2000 and 3500 rpm has been quantified by PIV. This was complemented by a Mie imaging study of the structure of multi-stream GDI sprays with injection timings of 90 120 and 150 0 CA. The vector fields and spray images at specific crankangles have been used to demonstrate the effect of inlet air velocity on the disruption and transport of the fuel spray. The study has shown that it is the early airflow through the valve gap that is more responsible for fuel disruption than the latter air motion.