Fundamental study of Direct Injection Diesel Engine Fuelled with Hydrogen (2nd Report: Analysis of Auto-ignition/Combustion Characteristics in Unsteady Hydrogen Jets)

In this study, authors investigated the characteristics of auto-ignition/combustion of high pressurized hydrogen jets to improve performances of a direct-injection, diesel engine fueled with hydrogen. The auto-ignition/ combustion of hydrogen were investigated in a constant-volume combustion vessel under simulated direct-injection diesel engine conditions. The parameters varied in the investigation included the injection pressure, ambient temperature and ambient oxygen concentration. The conclusions of this study are shown as follows: (1) Effect of ambient oxygen concentration in the ambient on auto-ignition delay and heat conversion efficiency is little at high ambient temperature range. Also, by reduction of ambient oxygen concentration, reduction of NO is possible. (2) In the case of the smaller orifice and multi hole, heat conversion efficiency is increased