Experimental and Modeling Study of NO and NO2 Storage and Release Characteristics of a Diesel-Cold Start Catalyst

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Department of Mechanical Engineering-Engineering Mechanics


A 2013 6.7L Cummins ISB (209 kW) diesel engine was used to quantify the NO, NO2, and NOx storage and release performance of the diesel cold start catalyst (dCSC™). The NOx storage experiments were performed over a range of temperatures from 80 to 250°C and NOx release experiments were performed at temperatures from 200 to 450°C. A 2-D diesel cold start catalyst (d-CSC) model was developed to predict NO, NO2 storage, and release characteristics along with the temperature distribution within diesel cold start catalyst (d-CSC) and the pressure drop across the d-CSC. This d-CSC model was calibrated using eight runs of experimental data that consisted of storage temperatures ranging from 80 to 250°C and release temperatures ranging from 200 to 450°C. The validation results show that the new d-CSC model can predict 200-s NOx storage and total NOx release capacity with a maximum root mean square (RMS) error of 0.02 and 0.10 NO2 g/L of substrate, respectively. The NO2/NOx ratio RMS error was within 24%. The RMS temperature errors for storage and release phases were within 3°C and the pressure drop model error was within 0.2 kPa. It is found that the dCSC™ shows significant low temperature NOx storage capability with a peak storage occurring from 125 to 150°C. The rapid NOx release was observed at temperatures above 200°C which is well within the operating range of the aftertreatment system after cold start period.

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Emission Control Science and Technology