The Influence of a Late In-Cylinder Air Injection on In-Cylinder Flow Measured with Particle Image Velocimetry (PIV)

During development of an air assisted, direct injection combustion system, it was found that an air pulse during the late part of compression stroke significantly shortened the combustion duration and extended the lean limits of the engine.

The effect of an injection of pure air through an air assist direct injector was studied with Particle Image Velocimetry, PIV.

Results showed that an air pulse during the compression stroke significantly speeded up in-cylinder velocities, which also was showed in the heat release analysis.

A system to use low density seeding particles was developed and is presented in the paper.