Experimental and Modeling Study of a Diesel Oxidation Catalyst (DOC) under Transient and CPF Active Regeneration Conditions

Xiaobo Song; Harsha Surenahalli; Jeffrey Naber; Gordon Parker; John H. Johnson

doi:10.4271/2013-01-1046

In this study, a DOC catalyst was experimentally studied in an engine test cell with a2010 Cummins 6.7L ISB diesel and a production aftertreatment system. The test matrix consisted of steady state, active regeneration with in-cylinder fuel dosing and transient conditions. Conversion efficiencies of total hydrocarbon (THC), CO, and NO were quantified under each condition.

A previously developed high-fidelity DOC model capable of predicting both steady state and transient active regeneration gaseous emissions was calibrated to the experimental data. The model consists of a single 1D channel where mass and energy balance equations were solved for both surface and bulk gas regions. The steady-state data were used to identify the activation energies and pre-exponential factors for CO, NO and HC oxidation, while the steady-state active regeneration data were used to identify the inhibition factors. The transient data were used to simulate the thermal response of the DOC. A calibration procedure was developed and the identified model parameters are presented.

The performance of the model was compared to the experimental results in terms of the outlet NO₂/NO_x ratios and CO, HC conversion efficiencies. The results show that the model is able to simulate the DOC performance under steady-state and transient conditions and during active regeneration conditions. The model is able to predict the outlet temperatures and HC concentrations within the measurement uncertainties. An inhibition factor that accounts for the inhibition of reactions in the presence of high hydrocarbon concentrations was determined so that the outlet HC and NO₂ concentrations during active regeneration were simulated accurately.

Experimental and Modeling Study of a Diesel Oxidation Catalyst (DOC) under Transient and CPF Active Regeneration Conditions 2013-01-1046

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