Effect of Aromatics on Fuel Spray Ignition

Abstract

The effects of aromatic hydrocarbons in fuel oils on autoignition of fuel sprays in hot surrounding air were studied using a rapid compression machine and a total gas sampling device. Ignition delays and concentrations of gaseous hydrocarbons produced by fuel decomposition were measured for test fuels which have various contents of aromatics. The results show that the paraffinic contents in the fuels were the main source initiating ignition reactions and that the accumulation of lower hydrocarbons due to pyrolysis or weak oxidation before significant heat release occurs is suppressed in fuels containing large quantities of aromatic hydrocarbons. Consumption of much oxygen by aromatic compounds early in the ignition delay periods may obstruct the oxidation process of paraffinic hydrocarbons.