2020 Volume 51 Issue 4 Pages 655-662
A high-accuracy knocking prediction model with low computation loads is necessary for the efficient development of SI engines using engine performance simulators. 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 sum of Δt/τ reaches 1, the parts of a profile of heat release rate can be integrated to be the whole 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 constant-volume ignition delay time produced using a detailed reaction mechanism. In the third report, error factors in in-cylinder autoignition prediction using the Livengood-Wu integral with the ignition delay time equations were investigated. Errors are accumulated during the H2O2 loop induction part of ignition process. In the present report, an error correction equation has been developed, which can cancel the advances of timing predicted using the Livengood-Wu integral from ignition timing. Finally, an autoignition prediction model using “reverse Livengood-Wu integral” with the ignition delay time and error correction equations has been proposed.
