Basic Study and Engine Trial on Diesel NOx Reduction by Controlling Mixing

This paper investigates the effect of enhancing mixing of spray tip region on NOx reduction from diesel engines. The concept is based on the fact that dominant part of NOx formation is the flame tip region with weak mixing intensity. Two methods to realize our concept were attempted in a constant volume combustion bomb and in an actual diesel engine. One is the two-stage injection and another is the method with a jet created by combustion of premixed charge in a turbulence cell. The paper presents results of variety trials of experiment, and it discusses necessary means to achieve the concept.