Fuel Distribution in an Air Assist Direct Injected Spark Ignition Engine with Central Injection and Spark Plug Measured with Laser Induced Fluorescence

The fuel distribution in an air assist direct injection engine was measured with Planar Laser Induced Fluorescence, PLIF. The engine was fueled with isooctane and 3-pentanon was used as the fuel tracer.

The optical engine was of the prolonged piston type, with a quartz ring in the upper part of the cylinder. Both the fuel injector and the spark plug were centrally located in the cylinder head. Two different pistons were examined: flat piston and bowl in piston.

Results show that the differences in fuel stratification are very large for the flat piston compared to the piston with a bowl.