My research interests involve advanced combustion engines using high-fidelity direct numerical simulation (DNS). DNS is used to investigate the effects of thermal/compositional/reactivity stratification and turbulence on the ignition characteristics of hydrocarbon fuel/air mixtures under the low-temperature conditions of Homogeneous Charge Combustion Ignition (HCCI), Stratified-Charged Compression Ignition (SCCI), and Reactivity-Controlled Compression Ignition (RCCI). Chemical explosive mode analysis (CEMA) is adopted to identify key species and controlled reactions of HCCI-type combustion. Currently, my research focuses on pre-ignition in HCCI engines to understand underlying mechanism of knock and super-knock, thereby extending the regime diagram.