Characteristics of Low NOx Formation of Over-Rich-Mixture Plume Combustion in High Pressure Direct Injection SI Hydrogen Engines

Abstract

A direct cylinder injection system is expected as a fueling system in hydrogen fueled S.I. engines since it has a potentiality to mitigate decrease in output power which is disadvantageous nature of gas fuel engines. Technology to reduce fairly high NOx emissions level that is characteristics of direct injection SI hydrogen engines, however, is still underway of development In this study new concept of optimizing combination of injection, ignition and combustion based on an application of high pressure injection up to 20 MPa, which enables notable reduction in NOx emissions without any tradeoffs on decrease in output power and thermal efficiency is introduced in direct injection S.I. engines.