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

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.

KEYWORDS:

• Plasma-assisted ignition
• ethanol-gasoline surrogate
• ultra-lean mixture
• high pressure
• kinetic mechanism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors would like to acknowledge the financial support by the National Natural Science Foundation of China (Grant number 52076148).