Analysis of an HCCI engine combustion using toluene reference fuel for different equivalence ratios – Comparison of experimental results with CFD and SRM simulations

Abstract

In this study; performance of 0-D and Computational Fluid Dynamics (CFD) software with two different chemical mechanisms are investigated in an HCCI engine using toluene reference fuel (79% toluene and 21% n-heptane). For 0-D simulations, stochastic reactor model (SRM) has been used. SRM and CFD software were compared to each other for HCCI engine simulation by investigating in-cylinder pressure variations, Heat Release Rate (HRR) and emissions. For toluene reference fuel, a semi-detailed and a reduced chemical kinetic mechanisms were used during the simulations. It is observed that CFD and SRM simulations with reduced mechanism give better results for capturing pressure and HRR for lower lambda (λ) values. But only CFD simulation with reduced mechanism could capture the experimental pressure and HRR results for higher lambda (λ) values. On the other hand semi-detailed mechanism could predict early cold combustion reactions for all simulation strategies. It could be say that all simulation approaches with two different mechanism have almost similar results for HCCI combustion emissions.