Detailed chemistry promotes understanding of octane numbers and gasoline sensitivity

Detailed kinetic models of pyrolysis and combustion of hydrocarbon fuels are now reliable tools which can aid the design of internal combustion engines required to meet the increasingly stringent pollutant formation and engine efficiency standards. The aim of this paper is to discuss and verify the potential of these kinetic models in analyzing the knock related combustion behavior of hydrocarbon fuels with particular regard to octane numbers and octane sensitivity. Detailed chemistry not only helps to explain the different reactivities of alkanes and alkenes but also the combustion behavior of hydrocarbon mixtures. A two-zone model of a spark ignition engine, coupled with the detailed chemistry of combustion processes, was developed and utilized for the predictions of octane numbers. This model explains the effect of various components on the knocking behavior of the fuel under different operating conditions and is thus a useful tool both in formulating new fuels and designing new engines.