Development of a reduced chemical kinetic mechanism for a gasoline surrogate for gasoline HCCI combustion

A reduced chemical kinetic mechanism consisting of 48 species and 67 reactions is developed and validated for a gasoline surrogate fuel. The surrogate fuel is modeled as a blend of iso-octane, n-heptane, and toluene. The mechanism reduction is performed using sensitivity analysis, investigation of species concentrations, and consideration of the main reaction path. Comparison between ignition delay times calculated using the proposed mechanism and those obtained from shock tube data show that the reduced mechanism can predict delay times with good accuracy at temperatures above 1000 K. The mechanism can also predict the two-stage ignition at the moment of ignition. A rapid compression machine (RCM) is designed to measure ignition delay times of gasoline and gasoline surrogates at temperatures between 890 and 1000 K. Our experimental results suggest that a new gasoline surrogate that has a different mixture ratio than previously defined surrogates is the most similar to gasoline. In addition, the reduced mechanism is validated for the RCM experimental conditions using CFD simulations.