This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Optical Investigation on the Ability of a Cordierite Substrate Mixing Device to Combat Deposits in SCR Dosing Systems
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2015 by SAE International in United States
Annotation ability available
Selective catalytic reduction (SCR) has become the mainstream approach for removing heavy-duty (HD) diesel engine NOx emissions. Highly efficient SCR systems are a key enabling technology allowing engines to be calibrated for very high NOx output with a resultant gain in fuel consumption while still maintaining NOx emissions compliance. One key to the successful implementation of high efficiency SCR at elevated engine out NOx levels is the ability to introduce significantly more AdBlue into the exhaust flow while still ensuring complete ammonia production and avoiding the formation of deposits.
This paper presents a body of experimental work conducted on an exhaust test bench using optical techniques including high-speed imaging and phase Doppler interferometry (PDI), applied under representative exhaust conditions to a HD diesel engine after-treatment system with optical access inside the mixer tube.
Two different sprays were used to dose AdBlue onto the mixing device. A three-hole injector and a single-hole pressure-swirl injector were characterised in ambient and heated exhaust flow conditions. A metallic two-stage mixer and an uncoated cordierite ceramic substrate mixer were compared and demonstrated the ability of the substrate mixer to reduce deposit formation at higher dosing rates inside the mixer tube when used with the correct spray type. High-speed imaging revealed the ability of the substrate to absorb injected AdBlue spray at cooler exhaust temperatures. However, using the incorrect spray can lead to liquid saturation inside the substrate channels, which is detrimental due to the formation of deposits on the rear face of the substrate.
CitationLockyer, T., Reid, B., Hargrave, G., Gaynor, P. et al., "Optical Investigation on the Ability of a Cordierite Substrate Mixing Device to Combat Deposits in SCR Dosing Systems," SAE Technical Paper 2015-01-1039, 2015, https://doi.org/10.4271/2015-01-1039.
- Stanton , D. , Charlton , S. , and Vajapeyazula , P. Diesel Engine Technologies Enabling Powertrain Optimization to Meet U.S. Greenhouse Gas Emissions SAE Int. J. Engines 6 3 1757 1770 2013 10.4271/2013-24-0094
- Ohrnberger , T. , Becker , C. , and Doehring , C. Assessment of Tier 4 Final Aftertreatment Strategies SAE Technical Paper 2012-01-1953 2012 10.4271/2012-01-1953
- Johnson , T. Vehicular Emissions in Review SAE Int. J. Engines 5 2 216 234 2012 10.4271/2012-01-0368
- Zheng , G. , Fila , A. , Kotrba , A. , and Floyd , R. Investigation of Urea Deposits in Urea SCR Systems for Medium and Heavy Duty Trucks SAE Technical Paper 2010-01-1941 2010 10.4271/2010-01-1941
- Seo , J. Aftertreatment Package Design for SCR Performance Optimization SAE Technical Paper 2011-01-1135 2011 10.4271/2011-01-1135
- Munnannur , A. , Chiruta , M. , and Liu , Z. Thermal and Fluid Dynamic Considerations in Aftertreatment System Design for SCR Solid Deposit Mitigation SAE Technical Paper 2012-01-1287 2012 10.4271/2012-01-1287
- Smith , H. , Lauer , T. , Mayer , M. , and Pierson , S. Optical and Numerical Investigations on the Mechanisms of Deposit Formation in SCR Systems SAE Int. J. Fuels Lubr. 7 2 525 542 2014 10.4271/2014-01-1563
- De Rudder , K. , Chauvin , C. Close coupled DOC-mixer-SCR for Tier 4 final AVL International Commercial Powertrain Conference 2013
- Zheng , G. , Gardner , T. , Kotrba , A. , Golin , M. et al. Development of Urea SCR Systems for Large Diesel Engines SAE Technical Paper 2011-01-2204 2011 10.4271/2011-01-2204
- Lundstrom , A. , Andersson , B. , Olsson , L. Urea thermolysis studied under flow reactor conditions using DCS and FT-IR Chemical Engineering Journal 150 544 550 2009 10.1016/j.cej.2009.03.044
- Schaber , P. , Colson . J. , Higgins , S. , Thielen , D. et al. Thermal decomposition (pyrolysis) of urea in an open reaction vessel Thermochimica Acta 424 131 142 2004 10.1016/j.tca.2004.05.018
- Fang , H. , DaCosta , H. Urea thermolysis and NOx reduction with and without SCR catalysts Applied Catalysis B: Environmental 46 17 34 2003 10.1016/S0926-3373(03)00177-2