Kinetics of Low-Temperature Plasma-Assisted Ignition of Ethanol-Gasoline Surrogate under Gasoline Engine like Conditions

Abstract

ABSTRACT The plasma-assisted reaction kinetic mechanism for high-voltage nanosecond discharge at high pressure was developed for lean and stoichiometric ethanol-gasoline surrogate/O2/N2/AR mixture. The numerical results show that plasma-assisted ignition of ethanol-gasoline surrogate is mainly associated with the electron impact dissociation of O2, nC7H16, iC8H18 and C2H5OH molecules and excited O2* produced from electron impact during discharge phase. The generation of H and O atoms, radicals and O2* facilitates plasma-assisted ignition (PAI). The formation of C2H5OH+, C8H18 + and O− increases ignition delay time. PAI improves the ignition stability of lean mixture mainly by increasing the reaction rate in reaction iC8H18+ HO2⇋C8H17+ H2O2. The reaction CH3+ HO2⇋CH4+ O2 promotes auto-ignition. But it delays the plasma-assisted ignition of stoichiometric mixture while it facilitates plasma-assisted ignition in lean mixture. The ignition delay time in lean-burn conditions can be shortened only by a proper timing of low-temperature plasma discharge at low temperature.