Evaluation of Kinetic Models for Autoignition of Automotive Reference Fuels in HCCI Applications


Abstract: Clean and efficient engine research and development work needs reliable models where autoignition for automotive reference fuels are described well. These models have to include chemistry containing numbers of reactions. The predictive capability depends more on the quality of reactions describing the chemical phenomena in the mechanism than on the number of the reactions. In this work three chemical mechanisms containing 1034, 74 and 63 species for primary reference fuels (PRFs) are compared with respect to the prediction of autoignition at conditions relevant for HCCI Engines and knock in SI Engines. After validation to experimental data for iso-octane, n-heptane and mixtures of the two fuels obtained from shock tube experiments over the temperature range 700 < T < 1200K at pressures 15-60 bars, a single zone engine model is used to simulate the point of autoignition and compared against experimental results obtained from an HCCI engine in KTH labs in Stockholm. The work shows the performance of the chemical mechanisms in prediction of autoignition delay time in HCCI engines.

Keywords: Autoignition, HCCI, PRF, Chemical mechanism, Short mechanism

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