Computer simulations and experiments of normal and branched alkane adsorption in complex carbonaceous materials

摘要

Carbonaceous engine deposits are porous materials that are known to accumulate on the inner surfaces of spark-ignition engines and have been linked to impaired engine performance]!]. One possible mechanism by which this occurs is selective adsorption of fuel components in the deposits, reducing the effective octane number of the fuel. In other proposed mechanisms deposits provide catalytic sites, altering the combustion reaction, and act as thermal hotspots, leading to premature ignition of the fuel mixture. Since in each-of these cases the porous structure of the deposits plays a key role, it is important to develop a systematic approach to characterize this structure. In recent publications we have proposed a variant of the typical model for the characterisation of activated carbons that combines predictive molecular simulations with a limited number of experimental isotherms to determine the internal structure of these carbonaceous deposits[2, 3], This characterisation has then been used to show that selective adsorption of key fuel components is a feasible cause for degradation in the engine performance^, 3]. We outline in greater detail the systematic development of this model, reiterate on the findings of these studies, and examine the sensitivity and robustness of the model.