Technical Paper
CFD Optimisation of the In-Cylinder Flow Patterns in a Small Unit Displacement HSDI Diesel Engine for Off-Highway Applications
2006-11-13
2006-32-0001
The aim of the paper is to provide information about the in-cylinder flow field optimisation in a high speed, direct injection (HSDI) four valve per cylinder diesel engine for off-highway applications. Fully transient CFD analyses of different valve profile strategies for the intake and compression strokes are at first performed, in order to evaluate the effects on both engine permeability and in-cylinder flow field evolution. Modifications are applied to each intake valve separately: gradually stretched cam profiles are imposed so that strategies range from the standard operation, i.e. the adoption of a unique cam profile for the two intake valves, up to the limit case characterized by a 40 % difference between the intake valves maximum valve lifts for three different engine conditions.