The Spontaneous Ignition of Hydrocarbon Fuels in a Flowing System

Abstract

An apparatus is described in which the ignition delays of fuel sprays have been measured over a range of pressures (30–60 atm.), temperatures (770–980°K), and velocities up to 70 ft/s (21 m/s), in a continuously flowing air stream. Experiments have been made over this range of conditions with 21 hydrocarbon fuels and the appropriate values of ignition delay for any given engine or fuel can be interpolated. For the engine designer, equations are recommended relating ignition delay, air pressure, and temperature for a range of commercial fuels from diesel fuel to a premium grade gasoline. Curves are presented indicating the variation of ignition delay with cetane number and octane number, and a relationship between these two parameters has been derived.