A Study of Mixture Formation and Combustion for Spray Guided DISI

A Spray Guided DISI (Direct Injection Spark Ignition) is being proposed as a next-generation DISI and is expected to reduce the fuel consumption and the emissions than a Wall Guided DISI that is currently in the mainstream. With the aim of developing a Spray Guided DISI, the evaluation technologies for the spray behavior and the combustion characteristics in a single cylinder transparent engine, the measurement technologies for the mixture formation by LIEF (Laser Induced Exciplex Fluorescence) method and using a Fast Response FID (Flame Ionization Detector), and the analysis technologies for the spray behavior and the mixture formation with CFD (Computational Fluid Dynamics) technology were established. Based on these evaluation techniques, the behavior of spray and mixture formation by a Swirl Injector and a Multi Hole Injector were evaluated.

As a result, it was found that the characteristics of the Multi Hole Injector are suitable for the Spray Guided DISI because it is less affected by in-cylinder airflow since the spray penetration force is strong. Furthermore, since it was recognized that there was room for improvement in mixture formation in the Multi Hole Injector that was evaluated, improvement measures was examined and the Multi Hole Injector was improved. Then the spray and combustion behavior of the improved Multi Hole Injector was examined and the establishment of spray-guided combustion was confirmed.