Abstract
A correlation of ignition delay time with research octane number (RON) and critical compression ratio (CCR) has been investigated by using detailed chemical kinetic models of 36 alkanes for further understandings of the autoignition phenomenon in engine related to the chemical structure of fuel molecule. All the ignition delay times of stoichiometric alkane/air mixtures are equal at each initial temperature and pressure corresponding to the top dead centre (TDC) condition of CCR. From the comparisons of temperature and species profile in engine and constant volume reactor calculation, it was confirmed that the reactions before TDC is insensitive to ignition timing. Thus, RON reflects only the reaction kinetics of TDC temperature and pressure. This facts would lead to the straightforward estimation of RON.
