Gasoline direct-injection spark-ignition engines and gasoline direct-injection compression-ignition engines have received attention due to their higher fuel economy with respect to conventional port fuel injected internal combustion spark-ignition engines. Combustion modeling of these types of engines requires a fuel surrogate that mimics both physical (e.g., evaporation) and chemical (e.g., combustion) characteristics of the gasoline fuel. In this work, we propose a novel methodology for the formulation of a gasoline surrogate based on the essential physical and chemical properties of the target gasoline fuel. Using the proposed procedure, a surrogate with seven components has been identified to emulate the physical and chemical characteristics of a real non-oxygenated gasoline fuel, RD387. A surrogate kinetic mechanism was developed by combining available detailed kinetic mechanisms from the Lawrence Livermore National Laboratory library. The modeling results for distillation curve, ignition delay and laminar flame speed were validated against available experimental data in the literature. The surrogate and gasoline fuels display similar physical/chemical properties, including distillation curve, H/C ratio, density, heating value, and ignition behavior and flame propagation over a wide range of pressures, temperatures, and equivalence ratios.

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A new detailed kinetic model of ethanol with 107 species and 1795 reactions was developed using a reaction mechanism generator and extensively validated against measured ignition delay times, laminar flame speeds, and time-resolved species concentrations. Ignition delay experiments were conducted at pressures of 15, 20, and 30 bar, a temperature range of 850−1000 K, and equivalence ratios of 0.5, 1.0, and 2.0 using an optically accessible rapid compression machine. The effect of oxygen concentration on the ignition delay at a fixed equivalence ratio was also measured and investigated using the new kinetic model. A high-speed camera was used to investigate the autoignition process and chemiluminescence emission at low-tointermediate temperatures. Different combustion behaviors with respect to the chemiluminescence color and intensity were identified and briefly explained. The new combustion kinetic model predicted the measured data from this work and those available in the literature quite well.

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