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Calibration of a LNT-SCR Diesel Aftertreatment System
Technical Paper
2007-01-1244
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
An investigation into the post-LNT NH3 generation and NOx slip over an LNT was completed for the purposes of determining the proper calibration for NOx reduction over a downstream SCR. Experiments were conducted in an engine dynamometer on the DW12 2.2L diesel engine that was calibrated for rich operation.
The catalyst system was evaluated at 325°C for three different engine speed/load points. Engine speeds of 1750, 2000, and 2500 rpm were chosen, resulting in a LNT space velocities of 35,000 - 68,000 hr-1. Increased lean times were tested, which resulted in NOx loadings on the LNT that ranged from 0.10 - 0.50 grams NOx/L catalyst. In addition, varied degrees of richness were tested, corresponding to lambda sensor readings of 0.90, 0.92, and 0.94.
LNT performance was evaluated based on it's ability to provide a stoichiometric ratio of reactants to the SCR for NOx conversion. Gross and net NOx conversion was evaluated for a LNT-SCR system. Optimal NOx conversion for this type of system required a balance between providing sufficient reductant for NH3 generation without poisoning the SCR from HC. System performance was controlled by calibration of NOx loading and degree of richness.
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Authors
- Rachel Snow - Ford Motor Company Research and Advanced Engineering
- Giovanni Cavatatio - Ford Motor Company Research and Advanced Engineering
- Doug Dobson - Ford Motor Company Research and Advanced Engineering
- Cliff Montreuil - Ford Motor Company Research and Advanced Engineering
- Robert Hammerle - Ford Motor Company Research and Advanced Engineering
Topic
Citation
Snow, R., Cavatatio, G., Dobson, D., Montreuil, C. et al., "Calibration of a LNT-SCR Diesel Aftertreatment System," SAE Technical Paper 2007-01-1244, 2007, https://doi.org/10.4271/2007-01-1244.Also In
References
- Lambert C. et al. “Technical Advantages of Urea SCR for Light-Duty and Heavy-Duty Diesel Vehicle Applications” SAE 2004-01-1292 2004
- Parks J. Huff Shean Pihl Josh Choi Jae-Soon West Brian “Nitrogen Selectivity in Lean NOx Trap Catalysis with Diesel Engine In-Cylinder Regeneration” SAE 2005-01-3876 2005
- Li J. et al. “Sulfur Poisoning and Desulfation of the Lean NOx Trap” SAE 2001-01-2503 2001
- Cheng Y. et al. “Factors Affecting Diesel LNT Durability in Lab Reactor Studies” SAE 2004-01-0156 2004
- Gandhi H.S. Cavataio J.V. Hammerle R.H. Cheng Y. April 22 2004
- Lambert C. et al. “Urea SCR and DOF System for Diesel LDT/SUV Meeting Tier 2 Bin 5” US Department of Energy Diesel Engine Emissions Reductions (DEER) Conference Chicago September 2005
- Girard J. et al. “The Influence of Ammonia Slip Catalysts on Ammonia, N2O and NOx Emissions for Diesel Engines” September 25 2006
- Snow R. et al. “Robustness of a LNT-SCR System to Aging Protocol” SAE 07PFL-677 2007
- Theis Joseph R. et al. “NOx Release Characteristics of Lean NOx Traps During Rich Purges” SAE 2003-01-1159 2003
- Schmieg Steven J. Lee Jong-Hwan “Evaluation of Supplier Catalyst Formulations for the Selective Catalytic Reduction of NOx with Ammonia” SAE 2005-01-3881 2005
- West Brian et al. “Assessing Reductant Chemistry During In-Cylinder Regeneration of Diesel Lean NOx Traps” SAE 2004-01-3023 2004