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Comparison of Particulate Matter Emissions from Different Aftertreatment Technologies in a Wind Tunnel
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 08, 2013 by SAE International in United States
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Stringent emission regulations have forced drastic technological improvements in diesel after treatment systems, particularly in reducing Particulate Matter (PM) emissions. Those improvements generally regard the use of Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF) and lately also the use of Selective Catalyst Reduction (SCR) systems along with improved engine control strategies for reduction of NOx emissions from these engines. Studies that have led to these technological advancements were made in controlled laboratory environment and are not representative of real world emissions from these engines or vehicles. In addition, formation and evolution of PM from these engines are extremely sensitive to overall changes in the dilution process. In light of this, the study of the exhaust plume of a heavy duty diesel vehicle operated inside a subsonic environmental wind tunnel can give us an idea of the dilution process and the representative emissions of the real world scenario.
The subsonic environmental wind tunnel used for this study is capable of accommodating a full-sized heavy-duty truck and generating wind speeds in excess of 50mph. It was specifically designed and built by West Virginia University (WVU) to characterize the exhaust plume emitted of heavy duty vehicles. A 3 dimensional gantry system allows spanning the test section and sample regions in the plume with accuracy of less than 5mm. The gantry system was equipped with engine exhaust gas analyzers and Particulate Matter (PM) sizing instruments.
The investigation involves three different heavy-duty Class-8 diesel vehicles equipped with after-treatment technologies, representative of legacy and modern truck fleets in the USA. The three vehicles investigated are representative of three emission regulation standards, namely a US-EPA 2007 compliant, a US-EPA 2010 compliant and a baseline vehicle without any after-treatment technologies as pre US-EPA 2007, respectively.
The testing procedure includes three different vehicle speeds: idling, 20mph, and 35mph. The vehicles were tested on WVU's medium-duty chassis dynamometer, with the load applied to the truck reflecting the road load equation at the respective vehicle test speed. Wind tunnel wind speed and vehicle speed were maintained in close match during the entire test.
Results show that, the cross-sectional plume area increases with increase in distance away from tailpipe. Also indicating the cooling and dilution of the exhaust begins at close proximity to the tailpipe. The rate of cooling and dilution are greatest in early stages of the dilution process for the areas with high turbulence intensity, where strong mixing phenomena occurs. On the other hand, the core of plume observes a slower cooling and dilution rate. This difference is reflected in the PM formation and evolution of these two distinct regions, as shown by the particle size distributions and number concentrations.
CitationLittera, D., Cozzolini, A., Besch, M., Velardi, M. et al., "Comparison of Particulate Matter Emissions from Different Aftertreatment Technologies in a Wind Tunnel," SAE Technical Paper 2013-24-0175, 2013, https://doi.org/10.4271/2013-24-0175.
- Englert, N, “Fine Particles and Human Health: a Review of Epidemiological Studies”, Toxicology Letters, Vol. 149, pp. 235-242, (2004).
- Pope, C.A., “Mortality Effects of Longer Term Exposure to Fine Particulate Air Pollution: Review of Recent Epidemiological Evidence”, Inhalation Toxicology, Vol. 19, Suppl. 1, pp. 33-38, (2007).
- Brauer, M., Hoek, G., van Vliet, P., Meliefste, K., Fischer, P. H., Wijga, A., Koopman, L. P., Neijens, H. J., Gerritsen, J., Kerkhof, M., Heinrich, J., Bellander, T., Brunekreef, B. “Air Pollution from Traffic and the Development of Respiratory Infections and Asthmatic and Allergic Symptoms in Children”, American Journal of Respiratory Critical Care, Vol. 166, pp. 1092-1098, (2002).
- Brunekreef, B., Janssen, N. A., de Hartog, J., Harssema, H., Knape, M., and van Vliet, P., “Air Pollution from Truck Traffic and Lung Function in Children Living near Motorways”, Epidemiology, Vol. 8, pp. 298-303, (1997).
- Finkelstein, M. M., “Mortality and Indicators of Traffic Related Air Pollution”, Lancet, Vol. 361, pp. 430, (2003).
- World Health Organization, International Agency for Research on Cancer, “Diesel Engine Exhaust Carcinogenic,” Press Release No. 213, June 12th, (2012).
- Nightingale, J. A., Maggs, R., Cullinan, P., Donnelly, L. E., Rogers, D. F., Kinnersley, R., Fan, C. K., Barnes, P. J., Ashmore, M., Newman-Taylor, A., “Airway Inflammation after Controlled Exposure to Diesel Exhaust Particulates”, American Journal of Respiratory Critical Care Medicine, Vol. 162, pp. 161-166, (2000).
- Seagrave JC, Berger J, Zielinska B, Sagebiel J, McDonald JD, Mauderly JL., “Comparative Acute Toxicities of Particulate Matter and Semi-Volatile Organic Compound Fractions of Traffic Tunnel Air”, Toxicologist, Vol. 60, pp.192, (2001).
- Seagrave, J. C., McDonald, J. D., Gigliotti, A. P., Nikula, K. J., Seilkop, S. K., Gurevich, M., and Mauderly, J. L., “Mutagenicity and in Vivo Toxicity of Combined Particulate and Semivolatile Organic Fractions of Gasoline and Diesel Engine Emissions”, Toxicological Science, Vol. 70, pp. 212-226, (2002).
- Rönkkö, T., Virtanen, A., Vaaraslahti, K., Keskinen, J., Pirjola, L., Lappi, M., “Effect of dilution conditions and driving parameters on nucleation mode particles in diesel exhaust: Laboratory and on-road study”, Elsevier, Atmospheric Environment, 40 2893-2901, (2006).
- Gautam, M., Clark, N., Mehta, S., Boyce, J. et al., “Concentrations and Size Distributions of Particulate Matter Emissions from a Class-8 Heavy-duty Diesel Truck Tested in a Wind Tunnel,” SAE Technical Paper 2003-01-1894, 2003, doi:10.4271/2003-01-1894.
- Giechaskiel, B., Ntziachristos, L., Samaras, Z., Volker, S., Casati, R., Rainer V., “Formation potential of vehicle exhaust nucleation mode particles on-road and in the laboratory”, Elsevier, Atmospheric Environment, 39 3191-3138, (2005).
- Rae, William H. Jr., and Pope, Alan, (1984), “LOW-SPEED WIND TUNNEL TESTING”, ISBN-13: 978-0471874027.
- Littera, D., Velardi, M., Cozzolini, A., Yoder, G.S., Besch, M.C., Carder, D.K. and Gautam, M., “Integrated Physical and Chemical Measurements of PM Emissions of Dispersing Plume Heavy-Duty Diesel Truck: Wind Tunnel Studies (part I: Design and Commissioning)”, ASME Technical Paper ICEF2012-92091, (2012).