Numerical study of plasma produced ozone assisted combustion in a direct injection spark ignition methanol engine

Numerical simulations were performed to better assess the effect of plasma produced ozone assisted combustion. The effects of ozone (O3) addition from 0 to 7000 ppm in the intake manifold on cylinder pressure history, ignition delay, cylinder temperature history, and formaldehyde unburned methanol emission of a direct injection spark ignition (DISI) methanol engine during cold start and steady state conditions were simulated using computational fluid dynamics to couple the methanol chemical and kinetics reaction mechanisms. The model results show that the maximum cylinder pressure increases with increasing O3 addition for cold start and steady state modes. O3 addition can also significantly reduce ignition delay. Two maximum heat release rate peaks occurred with O3 addition for cold start and steady state modes. The effect of O3 addition on combustion processes of DISI methanol engines was significantly greater for cold start than steady state mode, particularly with higher O3 concentrations. The effects on formation and oxidation of formaldehyde were greater than for unburned methanol, and the effects on formation and oxidation of formaldehyde were also significantly greater for cold start than steady state mode.