This content is not included in your SAE MOBILUS subscription, or you are not logged in.
NOx-Conversion and Activation Temperature of a SCR-Catalyst Whilst Using a Novel Biomimetic Flash-Boiling AdBlue Injector on a LD Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 17, 2016 by SAE International in United States
Annotation ability available
Yearly 3.3 million premature deaths occur worldwide due to air pollution and NOx pollution counts for nearly one seventh of those . This makes exhaust after-treatment a very important research and has caused the permitted emission levels for NOx to decrease to very low levels, for EURO 6 only 0.4 g/kWh. Recently new legislation on ammonia slip with a limit of 10 ppm NH3 has been added , which makes the SCR-technology more challenging. This technology injects small droplets of an aqueous Urea solution into the stream of exhaust gases and through a catalytic reaction within the SCR-catalyst, NOx is converted into Nitrogen and Water.
To enable the catalytic reaction the water content in the Urea solution needs to be evaporated and the ammonia molecules need to have sufficient time to mix with the gases prior to the catalyst. The μMist® platform technology, inspired by nature, uses heat in order to increase the fluid temperature above the required saturation temperature within its constant volume chamber. When the outlet valve is opened the liquid breaks up into small droplets which eject and mix with the gases. This paper presents an investigation on how these heated droplets with SMD around 20μm affect the catalytic conversion and achieve high conversion whilst the ammonia slip is kept to a minimum for a few different mass flows. Injected pre-heated small droplets shows over 95 % catalytic conversion of NOx at exhaust temperatures around 200°C. During continuous operation at catalyst temperatures around 350°C - 370°C several test points reaching from 0.7 kg/h to 1.1 kg/h of AdBlue mass flow, achieved EURO VI legislation at the selected experimental conditions, not included in the WHSC (World Harmonized Steady-State Cycle), for both NOx and ammonia with higher than 98 % conversion efficiency.
CitationLarsson, P., Lennard, W., Dahlstrom, J., Andersson, O. et al., "NOx-Conversion and Activation Temperature of a SCR-Catalyst Whilst Using a Novel Biomimetic Flash-Boiling AdBlue Injector on a LD Engine," SAE Technical Paper 2016-01-2212, 2016, https://doi.org/10.4271/2016-01-2212.
- Lelieveld, J., Evans, J.S., Fnais, M., Giannadaki, D. et al., "The contribution of outdoor air pollution sources to premature mortality on a global scale," Nature Vol 525, 2015, doi: 10.1038/nature15371.
- Dieselnet, “Emission Standards EURO VI”, https://www.dieselnet.com/standards/eu, accessed May. 2016.
- Schmieg, S. and Lee, J., "Evaluation of Supplier Catalyst Formulations for the Selective Catalytic Reduction of NOx With Ammonia," SAE Technical Paper 2005-01-3881, 2005, doi:10.4271/2005-01-3881.
- Beheshti, N. and McIntosh, A.C., “A BIOMIMETIC STUDY OF THE EXPLOSIVE DISCHARGE OF THE BOMBARDIER BEETLE”, Int. J. of Design & Nature. Vol 1 No.1 (2006) 61-69, doi:10.2495/D&N-V1-N1-61-69
- Beheshti, N. and Walker, R., "Simulation of the μMist® Fuel Injection System's Fine Droplet Spray Air-Entrainment from Injection Point, within the Intake Manifold, to the Cylinder," SAE Technical Paper 2012-01-1659, 2012, doi:10.4271/2012-01-1659.
- Beheshti, N., Walker, R., Larsson, L., Copestake, A. et al., "µMist® - The next generation fuel injection system: Improved atomisation and combustion for port-fuel-injected engines," SAE Technical Paper 2011-01-1890, 2011, doi:10.4271/2011-01-1890.
- Cummins Filtration “AdBlue® Q&A - Aqueous Urea Solution (AUS 32) for NOx reduction in diesel engines” URL: https://www.cumminsfiltration.com/sites/default/files/pdf_archive/pdfs/product_lit/asia_pacific_brochures/LT36330AU.pdf - last downloaded 2016-07-06.
- Devadas, M., “Selective Catalytic Reduction (SCR) of Nitrogen Oxides with Ammonia over Fe-ZSM5”, Diss. ETH No. 16524, 2006.
- DieselNet Technology guide >>Diesel Catalyst, Revision 2005.05k https://www.dieselnet.com/tech/cat_scr.php - downloaded 2016-07-15.