Abstract
In the first report, the scientific nature of autoignition prediction using the Livengood-Wu integral was investigated. X of the Livengood-Wu integral is no more than the ratio of an integration step out of ignition delay time. Assumed that the profiles of heat release rate along the time normalized by ignition delay times are similar, when the integrated value reaches 1, the parts of a profile of heat release rate can be integrated to be the complete profile. In the second report, ignition delay time equations for a premium-gasoline surrogate fuel were developed, which can reproduce the temperature-, pressure-, and equivalence ratio-dependences of H2O2 loop induction time and ignition delay time produced using a detailed reaction mechanism, with high accuracies in a wide range of temperature and pressure. In the present report, the Livengood-Wu integral using these equations has been investigated. Unfortunately, this approach cannot be effective for all possible in-cylinder autoignitions. Prediction errors are significant for HCCI’s after TDC and end-gas autoignitions. Error factors in the Livengood-Wu integral using the high-accuracy ignition delay time equations have been investigated. Errors are accumulated during the H2O2 loop induction part of ignition process, which is contrary to the general impression that the primary error cause is the H2O2 loop dominant part.
