This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Thermal Management Strategies for SCR After Treatment Systems
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 8, 2013 by SAE International in United States
Annotation ability available
While the Diesel Particulate Filter (DPF) is actually a quasi-standard equipment in the European Diesel passenger cars market, an interesting solution to fulfill NOx emission limits for the next EU 6 legislation is the application of a Selective Catalytic Reduction (SCR) system on the exhaust line, to drastically reduce NOx emissions.
In this context, one of the main issues is the performance of the SCR system during cold start and warm up phases of the engine. The exhaust temperature is too low to allow thermal activation of the reactor and, consequently, to promote high conversion efficiency and significant NOx concentration reduction. This is increasingly evident the smaller the engine displacement, because of its lower exhaust system temperature (reduced gross power while producing the same net power, i.e., higher efficiency).
The proposal of the underlying work is to investigate and identify optimal exhaust line heating strategies, to provide a fast activation of the catalytic reactions on SCR. The main constrain is to limit the potential fuel consumption increase, and possibly to even increase global efficiency, and the chosen application is a small EU5-compliant diesel engine.
After an initial investigation, the research has been focused on main combustion control parameters, rather than on post-oxidation processes associated with late injections, in an effort to reduce eventual fuel penalties. The effect of each relevant engine control parameter has been analyzed on the test bench, observing the results in terms of exhaust system temperature and fuel efficiency. After this preliminary identification phase, different calibration strategies have been tested on the vehicle, executing several NEDC cycles. The most relevant comparisons are illustrated and critically discussed in the paper.
CitationCavina, N., Mancini, G., Corti, E., Moro, D. et al., "Thermal Management Strategies for SCR After Treatment Systems," SAE Technical Paper 2013-24-0153, 2013, https://doi.org/10.4271/2013-24-0153.
- “Regulation (EC) No 715/2007 of the European Parliament and of the Council of 20 June 2007 on type approval of motor vehicles with respect to emissions from light passenger and commercial vehicles (Euro 5 and Euro 6) and on access to vehicle repair and maintenance information”. Eur-lex.europa.eu. Retrieved 2011-02-02.
- Conway, R., Chatterjee, S., Beavan, A., Lavenius, M. et al., “Combined SCR and DPF Technology for Heavy Duty Diesel Retrofit,” SAE Technical Paper 2005-01-1862, 2005, doi:10.4271/2005-01-1862.
- Schär, C., Onder, C., Geering, H., and Elsener, M., “Control of a Urea SCR Catalytic Converter System for a Mobile Heavy Duty Diesel Engine,” SAE Technical Paper 2003-01-0776, 2003, doi:10.4271/2003-01-0776.
- Moon, S., Choi, B., Lee, H., Hyun, G. et al., “Development of DPF/SCR System for Heavy Duty Diesel Engine,” SAE Technical Paper 2012-01-0369, 2012, doi:10.4271/2012-01-0369.
- Covassin, F., Preziuso, M., De Cesare, M., and Serra, G., “A Mean Value Model of the Exhaust System with SCR for an Automotive Diesel Engine,” SAE Technical Paper 2009-24-0131, 2009, doi:10.4271/2009-24-0131.
- De Cesare, M. and Covassin, F., “Neural Network Based Models for Virtual NOx Sensing of Compression Ignition Engines,” SAE Technical Paper 2011-24-0157, 2011, doi:10.4271/2011-24-0157.
- Matthey Johnson, Focus On SCR Technology, Global Emissions Management, February 2012.
- Ericson, C., Westerberg, B., Odenbrand, I., and Egnell, R., “Characterisation and Model Based Optimization of a Complete Diesel Engine/SCR System,” SAE Technical Paper 2009-01-0896, 2009, doi:10.4271/2009-01-0896.
- Neely, G., Sarlashkar, J., and Mehta, D., “Diesel Cold-Start Emission Control Research for 2015- 2025 LEV III Emissions,” SAE Int. J. Engines 6(2):1009-1020, 2013, doi:10.4271/2013-01-1301.
- Honardar, S., Busch, H., Schnorbus, T., Severin, C. et al., “Exhaust Temperature Management for Diesel Engines Assessment of Engine Concepts and Calibration Strategies with Regard to Fuel Penalty,” SAE Technical Paper 2011-24-0176, 2011, doi:10.4271/2011-24-0176.
- Krengel, E., “Development of IMEP Analysis for Transient Data,” SAE Technical Paper 2004-01-1463, 2004, doi:10.4271/2004-01-1463.