Cetane number vs. structure in paraffin hydrocarbons

By using a ‘reduced kinetic model’ for the spontaneous ignition of hydrocarbon–air mixtures, it is found that for n-paraffins in the diesel-fuel boiling range, there is a simple correlation between the ignition delay and the ratio of primary to secondary hydrogen atoms in the molecule. The reduced kinetic model also accounts successfully for the variation in ignition delay with chain-branching in isoparaffins, and for the acceleration of ignition in the presence of simple OH-radical sources.