Numerical simulation of combustion and soot under partially premixed combustion of low-octane gasoline

•In-cylinder combustion and soot particle with PAHs as precursors is modeled and estimated.•The SOI is advanced to −30 CAD (aTDC) to achieve the partially premixed combustion.•PPC presents typical stratified combustion and different from the spray-driven combustion.•Scatter plot of T- ϕ map overlaid with soot-NOX regimes is discussed.•Local in-cylinder temperature, soot mass, and particle number distribution are analyzed.