Gas Sampling Analysis of Compression Ignition Combustion Processes of Premixed Fuel Rich Mixture

Abstract

Gas sampling analysis of compression ignition combustion processes in stoichiometric and rich mixtures were conducted to study the differences in histories of intermediates at around the critical equivalence ratio for smoke emission. The results showed that low temperature oxidation processes before second heat release in fuel rich conditions were the same as that in lean or stoichiometric conditions. The results also showed that carbon monoxide, hydrogen, methane and acetylene was produced after second heat release in fuel rich conditions, and benzene could be seen in higher equivalence ratio than the critical equivalence ratio for smoke emission. Benzene concentration kept increasing after heat release, which corresponded to the decrease of acetylene. Then the critical equivalence ratio seems to have a relationship with the formation limit of benzene, which supposed to be the core of soot precursor PAH.