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The autoignition characteristics of military aviation fuels (JP-5 and JP-8), proposed camelina-derived hydroprocessed renewable jet fuel replacements (HRJ-8 and HRJ-5), Fischer-Tropsch fuels (Shell and Sasol), three Sasol isoparaffinic solvents, as well as 50/50 volumetric blends of the alternative fuels with the conventional fuels are examined. Experiments were conducted in a rapid compression machine and shock tube at compressed temperatures of 625 K 6 T c 6 1000 K, a compressed pressure of 20 bar, and under stoichiometric and lean conditions. Several implicit properties of the alternative fuels prompted a study of the influence of chemical composition on autoignition, including the influence of isoparaffinic, cycloparaffinic, and aromatic structures. In addition, interesting combustion phenomena at low-temperature conditions are investigated under lean conditions, specifically concerning jet fuel blend reactivity, where a convergence in blend reactivity to the reactivity of either a conventional or alternative fuel is observed.

Turbulent Jet Ignition is an advanced pre-chamber ignition enhancement technique for spark ignition engines that uses a discharging jet of hot combusting gases to initiate main chamber combustion. The jet acts as a distributed ignition source, leading to fast burn rates and increased combustion stability. Experiments were performed in an optically accessible rapid compression machine using liquid iso-octane to study the effects of auxiliary fuel injection and ignition distribution due to nozzle geometry. A custom low-flow fuel injector was used to overcome previous limitations of using liquid fuel in the pre-chamber. Jet induced autoignition behavior was also studied in depth by considering high-speed images, pressure traces, and pressure derivative data.