This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Investigation on Uniformity Indices Used for Diesel Exhaust Aftertreatment Systems
Technical Paper
2008-01-0613
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
When developing diesel exhaust aftertreatment systems the often constrained packaging envelope is a challenge. In addition, the stringent emission legislation can necessitate the injection of additives, for example urea and/or hydrocarbons, to achieve performance targets. In such cases, a good distribution of reactants over the catalyst surface is beneficial but might be difficult to achieve. The uniformity of these distributions is often studied separately using a non-dimensional measure denoted as the Uniformity Index (UI). However, a combination of the exhaust gas UI and the UI for the additive is also interesting to study.
In this work the origin, applicability and advantages of the uniformity index is discussed as a guide for developing diesel exhaust aftertreatment systems. Moreover, a matching index (UIα) is proposed for the analysis of systems where additives are injected. It is found that two skew distributions can give a good conversion if the profiles match.
A sensitivity study for some critical parameters is also performed. Trade-off relations between conversion and space velocity as a function of the discussed uniformity indices are given. Most of this work is carried out using a validated modelling tool developed for catalyst systems. This tool allows for calculation of two dimensional distributions of reactants and products. An application example is also given where the theoretical discussion is compared with experimental data.
Recommended Content
Authors
Citation
Johansson, Å., Wallin, U., Karlsson, M., Isaksson, A. et al., "Investigation on Uniformity Indices Used for Diesel Exhaust Aftertreatment Systems," SAE Technical Paper 2008-01-0613, 2008, https://doi.org/10.4271/2008-01-0613.Also In
References
- Karlsson, M. et al. A combined 3D/Lumped modeling approach to ammonia SCR after-treatment systems: application to mixer designs, in SAE 2006 SAE Technical Paper Series no: 2006-01-0469
- Weltens, H. et al. Optimisation of Catalytic Converter Gas Flow Distribution by CFD Prediction, in SAE 1993 SAE Technical Paper Series no: 930780
- Martin, A.P. et al. Effect of Flow Distribution on Emissions Performance of Catalytic Converters, in SAE 1998 SAE Technical Paper Series no: 980936
- Chen, M. Williams S. Modelling and Optimization of SCR-Exhaust Aftertreatment Systems, in SAE 2005 SAE Technical Paper Series no: 2005-01-0969
- Zhang, X. Romzek M. 3-D Numerical Study of Flow Mixing in Front of SCR for Different Injection Systems, in SAE 2007 SAE Technical Paper Series no: 2007-01-1578
- Zhang, X. Romzek M. Morgan C. 3-D Numerical Study of Mixing Characteristics of NH 3 in front of SCR, in SAE 2006 SAE Technical Paper Series no: 2006-01-3444
- Girard, J.W. et al. Flow Uniformity Optimization for Diesel Aftertreatment Systems, in SAE 2006 SAE Technical Paper Series no: 2006-01-1092
- Stratakis, G.A. Stamatelos A.M. Flow maldistribution measurements in wall-flow diesel filters Proc. Instn Mech. Engrs Part D: Journal of Automobile Engineering 2004 218 995 1009
- Schär, C.M. Control of a Selective Catalytic Reduction Process 2003 Institut für Mess- und Regeltechnik, Swiss Federal Institute of Technology Zürich
- Kleeman, P.M. Beschichtung von Cordierit-Wabenkörpern für die Selektive Katalytische reduktion von Stickoxiden 1999 Swiss Federal Institute of Technology Zürich