Development of a model for the lean NOx catalytic reaction with hydrocarbon adsorption and desorption

A numerical model for lean NOx catalytic reaction in consideration of hydrocarbon adsorption and desorption process, which is capable of predicting the performance of diesel lean NOx catalyst using diesel fuel as a supplemental reductant, has been developed. This model is based on our simplified kinetics for the adsorption and desorption of hydrocarbons, for the oxidation of hydrocarbons, and for the reduction of NOx by hydrocarbons including the desorbed one. The adsorption of diesel exhaust hydrocarbons was expressed by the Freundlich-type isotherm that has the adsorption equilibrium constant of exponential temperature dependence. The behavior of HC and NOx reactions and HC adsorption and desorption in diesel exhaust has been simulated successfully.