Computational Investigation of HCCI Engine Performance With Fuel Reforming Effect on Lean Ethanol

In this study, a mechanism containing ethanol reactions is employed and the effects of exhaust gas fuel reforming on operation parameters such as ignition timing, burn duration, temperature, pressure and NO_x emission are studied in which a homogeneous mixture is assumed. The results show that hydrogen in the form of reformed gas helps in lowering the intake temperature required for stable HCCI operation. It is concluded that the addition of hydrogen advances the start of combustion in the cylinder. This is a result of the lowering of the minimum intake temperature required for auto-ignition to occur during the compression stroke, resulting in advanced combustion for the same intake temperatures. The obtained results from the model are compared with the experimental data published in the literature and the comparison showed a reasonable compatibility.