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Chassis Dynamometer Emissions Characterization of a Urea-SCR Transit Bus
Technical Paper
2011-01-2469
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
West Virginia University characterized the emissions and fuel economy performance of a 30-foot 2010 transit bus equipped with urea selective catalytic reduction (u-SCR) exhaust aftertreatment. The bus was exercised over speed-time driving schedules representative of both urban and on-highway activity using a chassis dynamometer while the exhaust was routed to a full-scale dilution tunnel with research grade emissions analyzers. The Paris speed-time driving schedule was used to represent slow urban transit bus activity while the Cruise driving schedule was used to represent on-highway activity. Vehicle weights representative of both one-half and empty passenger loading were evaluated. Fuel economy observed during testing with the urban driving schedule was significantly lower (55%) than testing performed with the on-highway driving schedule. Fuel economy during evaluations representing half passenger load, which represented a 10% higher vehicle weight than empty weight, were 6% over the Paris driving schedule and 3% lower over the Cruise schedule than that observed during evaluations representative of empty/curb weight. The u-SCR exhaust aftertreatment system presented emissions and performance testing challenges which had not previously been encountered with earlier model year diesel vehicles. These issues resulted from the temperature dependence of the u-SCR in reducing oxides of nitrogen and emissions system control algorithms used to raise catalyst temperature after startup and maintain catalyst temperature to provide for oxides of nitrogen reduction. Oxides of nitrogen emissions levels in the exhaust were highly dependent on the temperature of the aftertreatment system at the beginning of each test and the rate at which exhaust energy heated the aftertreatment system during post-startup operation. Cold-start distance-specific oxides of nitrogen emissions integrated over the entire drive schedule using the Paris driving schedule were 8.7 times higher than for hot-start tests and 2.7 times higher than for hot-start emissions runs over the Cruise driving schedule. A significant portion of the difference in cold and hot start oxides of nitrogen emissions were the result of lower u-SCR system temperatures during cold-start operation. Run-to-run variability in u-SCR temperature resulted in run-to-run NOx repeatability issues. Clearly the task of gathering chassis dynamometer data for inventory or model development use is made more difficult by the complexity of NOx reduction aftertreatment.
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Citation
Clark, N., McKain, D., Wayne, W., Carder, D. et al., "Chassis Dynamometer Emissions Characterization of a Urea-SCR Transit Bus," SAE Technical Paper 2011-01-2469, 2012, https://doi.org/10.4271/2011-01-2469.Also In
References
- Johnson, T. “Diesel Emission Control in Review,” SAE Technical Paper 2007-01-0233 2007 10.4271/2007-01-0233
- Johnson, T. “Diesel Emission Control in Review,” SAE Int. J. Fuels Lubr. 1 1 68 81 2009 10.4271/2008-01-0069
- Johnson, T. “Diesel Emission Control in Review,” SAE Int. J. Fuels Lubr. 2 1 1 12 2009 10.4271/2009-01-0121
- Johnson, T. “Review of Diesel Emissions and Control,” SAE Int. J. Fuels Lubr. 3 1 16 29 2010 10.4271/2010-01-0301
- Block, M. Clark, N. Wayne, S. Nine, R. et al. “An Investigation into the Emissions Reduction Performance of an SCR System Over Two Years' In-Use Heavy-Duty Vehicle Operation,” SAE Technical Paper 2005-01-1861 2005 10.4271/2005-01-1861
- Herner, J.D. Hu, S. Roberston, W.H. Huai, T. Collins, J.F. Dwyer, H. Ayala, A. “Effect of Advanced Aftertreatment for PM and NOx Control on Heavy-Duty Diesel Truck Emissions,” Environ. Sci. Technol. 43 15 5928 5933 2009
- Herner, J.D. Hu, S. Robertson, W.H. Huai, T. Chang, M.C. Rieger, P. Ayala, A. “Effect of Advanced Aftertreatment for PM and NOx Reduction on Heavy-Duty Diesel Engine Ultrafine Particle Emissions,” Environ. Sci. Technol. 45 6 2413 2419 2011
- Ligterink, N. de Lange, R. Vermeulen, R. Dekker, H. “On-road NOx emissions of Euro-V trucks,” TNO report MON-RPT-033-DTS-2009-03840 Ministry of Housing, Spatial Planning and the Environment (Ministerie van VROM) Netherlands 2009
- Wayne, W.S. Clark, N.N. Khan, ABM.S. Gautam, M. Thompson, G.J. Lyons, D.W. “Regulated and Non-regulated Emissions and Fuel Economy from Conventional Diesel, Hybrid-electric Diesel and Natural Gas Transit Buses,” Journal of the Transportation Research Forum 47 3 105 126 October 2008
- Wu, Y. Carder, D. Shade, B. “A CFR1065-Compliant Transportable/On-Road Low Emissions Measurement Laboratory with Dual Primary Full-Flow Dilution Tunnels,” Paper no. ICES2009-76090, ASME 2009 Internal Combustion Engine Division Spring Technical Conference May 2009
- Coroller, P. Plassat, G. “Comparative Study on Exhaust Emissions from Diesel and CNG Powered Urban Buses,” DEER Conference 2003
- Gautam, M. Clark, N. Riddle, W. Nine, R. et al. “Development and Initial Use of a Heavy-Duty Diesel Truck Test Schedule for Emissions Characterization,” SAE Technical Paper 2002-01-1753 2002 10.4271/2002-01-1753
- Clark, N.N. Rivero, E. McKain, D.L. Paramo, V.H. Wayne, W.S. Vergara, W. Barnett, R. Gautam, M. Thompson, G.J. Lyons, D.W. Schipper, L. “Evaluation of Emissions from New and In-Use Transit Buses in Mexico City,” Transportation Research Record 1987 42 53 June 2007
- Wayne, W.S. Clark, N.N. Nine, R.D. Elefante, D. “A Comparison of Emissions and Fuel Economy from Hybrid-Electric and Conventional-Drive Transit Buses,” Energy and Fuels 18 1 257 270 January 2004
- Clark, N. McKain, D. Sindler, P. Jarrett, R. et al. “Comparative Emissions from Diesel and Biodiesel Fueled Buses from 2002 to 2008 Model Years,” SAE Technical Paper 2010-01-1967 2010 10.4271/2010-01-1967
- Hsieh, M. “Control of Diesel Engine Urea Selective Catalytic Reduction,” Ph.D. Dissertation Ohio State University 2010
- Moos, R. Wedemann, M. Sporl, M. Reiß, S Fischeraur, G. “Direct Catalyst Monitoring by Electrical Means: An Overview on Promising Novel Principles,” Topics in Catalysis 52 2035 2040 2009