Development and validation of isooctane skeletal mechanisms based on LLNL detailed mechanism

This paper describes recent development of isooctane skeletal mechanisms for Homogeneous Charge Compression Ignition (HCCI) engines. Two skeletal mechanisms were constructed: one with 259 species and the other with 291 species. The former was developed for accurate predictions of Start of Combustion (SOC) and the latter aiming at accurate predictions of both SOC and emissions. Evaluations of the performances of these skeletal mechanisms were conducted under extensive conditions. Both skeletal mechanisms are found satisfactory in predicting SOC with a speeding up factor of 15-20. The expanded version is found necessary for accurate predictions of CO and unburned hydrocarbon emissions.