Comparative Study of the Capability of Mixture- and Liquid Based GDI Configurations to optimize a Lean Stratified SI-Combustion in a Two-Stroke, small Displacement Engine

The first part of the paper gives an overview of the environmental conditions with which a future two stroke engine must comply. The reasons for which a direct gasoline injection into the combustion chamber offers one of the most promising solutions are explained.

In order to understand the potential of different GDI-layouts to produce very lean stratified combustion behavior two different approaches are studied in detail. The latest version of the fuel/air mixture injection used by the F. A. S. T. engine is confronted with a basically liquid high-pressure layout, similar to the design used in automotive four-stroke passenger car engines.

A description is given of the basic fluid dynamics of the 50 cc engine used for the study as well as of the experimental and numerical tools applied.

The paper concludes with a detailed presentation of the obtained results as well as of the arguments retained to produce the final rating.