Experiments and Modeling on Chemical Kinetic Micro-Analysis of Gasoline-Ethanol Surrogates Oxidation for HCCI Engines
Adding ethanol to gasoline is an effective way to improve anti-knock quality and reduce emissions.
Computational fluid dynamic (CFD) model coupled with the gasoline-ethanol surrogate mechanism can be used
for fuel design. A semi-detailed mechanism (278 species and 1439 reactions) at medium and low temperatures and
experiments in a homogeneous charge compression ignition (HCCI) engine for the oxidation of gasoline-ethanol
surrogates were presented in this paper. The initial mechanism derived from detailed primary reference fuel and
semi-detailed ethanol mechanisms. In order to get a smaller-size model, directed relation graph with error
propagation (DRGEP) method was used to remove insignificant components efficiently, and quasi-steady state
assumption (QSSA) method was used to identify the species in quasi-steady-state. Subsequently, some
elementary reactions involving the formation and consumption of H and OH radicals were revised and the kinetic
parameters of the relevant elementary reactions were adjusted. To validate the mechanism, the HCCI experiments
for the oxidation of gasoline-ethanol surrogates were conducted under different operating conditions. The new
mechanism was also compared with the literature model by Li et al. (2019) under the selected operating
conditions. The present mechanism can not only perform macro analysis of HCCI combustion process, but also
can be coupled with CFD software to perform transient in-cylinder micro-field analysis efficiently.