Applied Catalysis in the Automotive Industry: Development of a Commercial Diesel Oxidation Catalyst Simulation Model Balanced for the Requirements of an Original Engine Manufacturer. Part 2, CO and HC Chemistry

Our previously developed model of NO x chemistry over a commercially used diesel oxidation catalyst has been extended by adding CO and HC chemistry. Synthetic gas bench experiments were conducted in order to elucidate mechanisms and provide the experimental foundation necessary for model calibration. Reactions tested and folded into the model include pure gas-phase CO oxidation, water-gas shift, and surface oxidation reactions for CO and HC. The majority of the experiments were performed at a space velocity corresponding to medium load in terms of driving conditions. The complete model was validated against engine test data. For that, it was necessary to assess the aging of the catalyst (in modeling terms translated to precious metal dispersion) used in the engine tests. After assuming a reasonable dispersion using engineering judgment, model validation against engine test data was performed. This showed the ability of the model to predict both trends and time resolved details.