A Study of the Ignition Delay of Diesel Fuel Spray Using a Rapid Compression Machine

Abstract

The ignition delay of a diesel fuel was studied using a rapid compression machine that was developed in a previous study. By applying the hot motered technique proposed by Yu and others, the delay from the ignition start to the oneset of exothermic reaction and the delay required to pressure recovery were measured. The sum of the two delays was assumed to be the net ignition delay. Tests were performed for a range of air temperatures, pressures and fuel quantities. The results obtained are as follows : The temperature dependence of the initial delay is low at high temperatures due to physical effects such as heating up and vaporisation. The pressure recovery delay is largely affected by a fuel-air mixing rate below 750 K. Based on data obtained, an empirical formula of net ignition delay was proposed.