Kinetic modeling of polycyclic aromatic hydrocarbons formation process for gasoline surrogate fuels

• A gasoline surrogate fuels mechanism with PAHs formation has been developed.
• Validation including ignition delays and laminar flame speeds for gasoline.
• Sensitivity analysis and rate of production analysis were performed.
• Key species profiles and PAHs profiles could be predicted by this mechanism.

It is very necessary to develop a comprehensive gasoline surrogate fuel chemical kinetic model that could accurately predict soot emissions and polycyclic aromatic hydrocarbons (PAHs) formation in internal combustion engines. Based on the consideration, this paper presents a toluene reference fuel (TRF) chemical mechanism to predict the PAHs formation process. This mechanism has been validated for ignition delays over a range of initial conditions covering the pressures from 15 to 60 bar, equivalence ratios from 0.5 to 2.0 and temperatures from 750 to 1280 K, especially for gasoline/air and two TRFs/air mixtures under engines conditions. Laminar flame speeds were also validated at low and high pressures. Furthermore, in order to guarantee the prediction accuracy of PAHs, premixed and opposed flow flames were simulated to validate the formation of PAHs and good agreements were obtained. Sensitivity analysis was performed to analyze the contribution of reactions to ignition delays and laminar flame speeds. Rate of production analysis was also carried out to identify the formation and consumption reaction pathways of A1 under different temperatures. The results indicated that the TRF–PAHs chemical mechanism could meet the demand of the PAHs simulation in engines. The proposed mechanism, which includes 219 species and 1229 reactions, is available as supporting Information for this article.