Investigating the kinetic effect of prenol on iso-octane auto-ignition by means of an experimental and modeling study

Abstract

• An experimental study of iso -octane/prenol blends is performed inside a RCM. • Validated kinetic models of the oxidation of the neat fuels are merged. • IDTs reflect the strong inhibiting behavior of prenol on low-temperature reactivity. • This effect is suggested to originate from combined gas-phase and catalytic effects. A detailed experimental and kinetic modeling study was dedicated to understand the reported octane hyperboosting effect of prenol, by means of the measurement of the ignition delay times of its blends with iso -octane, and measurement of the mole fraction profiles of the fuels and intermediates inside the ULille rapid compression machine. These results show that prenol addition leads to a reduction of the first-stage ignition phenomena and negative temperature coefficient behavior, which is only qualitatively captured by the model and is consistent with knock resistance improvement. It is suggested that this behavior is caused by two different factors. The first originates from gas-phase reactivity of prenol, and spans from the formation of unreactive unsaturated species through resonance-stabilized radicals, thereby constituting a competitive pathway for the radical pool generated by iso -octane. The second is of catalytic nature and cannot be captured by means of gas-phase kinetic modeling, but could also play an important role in the behavior of prenol in internal combustion engines.