Abstract
Abstract
A methodology is developed and applied to gain fundamental understanding how the late injection events required for the particulate filter regeneration increase the risk of oil dilution. A CFD methodology has been developed and verified by direct comparison to experimental test bench results and optical measurements in both standard operation and regeneration mode.
This methodology is used in combination with engine testing to identify the major sources for reduction of oil dilution. The first is the geometric shielding effect of the piston bowl and crown. The second is the thermal effect of the main injection flame, which protects the cylinder liner walls from liquid fuel contact. When post injected fuel enters into flame areas with high local temperature, the acceleration of both fuel vaporization and ignition delay reduces the post injection spray penetration through the combustion chamber and thus the wall wetting of the cylinder liner by liquid fuel impingement.