This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Oxidation Catalyst Effect on CNG Transit Bus Emissions
Technical Paper
2003-01-1900
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
Recently, the California Air Resources Board (CARB) has reported that tailpipe emission samples from a compressed natural gas (CNG)-fueled transit bus without aftertreatment had measurable levels of toxic compounds such as formaldehyde (HCHO) and nanoparticle (=50 nm) and mutagen emissions (Ames assay) that in some cases were greater than that of a similar diesel transit bus equipped with either a diesel oxidation catalyst (DOC) or a diesel particulate filter (DPF) and fueled by ultra-low sulfur diesel (ULSD) [1, 2, 3]. Therefore, CARB has investigated the effectiveness of oxidation catalyst (OC) control for CNG bus applications. This study includes results for regulated gaseous and non-methane hydrocarbon (NMHC) emissions, non-regulated hydrocarbon emissions of toxic risk significance, and total particulate matter (PM). Two driving cycles were investigated: the Central Business District (CBD) cycle and Steady-State (SS) cruise condition at 55 mph.
The catalyst showed statistically significant reduction of total PM, total hydrocarbons (HC), NMHC, and carbon monoxide (CO). HCHO emissions were reduced by the catalyst by over 95% over both CBD and SS cycles. 1,3-butadiene emissions were reduced to levels below detection. Toxic aromatic HC's such as benzene also appeared to be reduced by the catalyst, but a larger data set is required to establish statistical significance. Little effect of the catalyst was found on methane (CH4) and oxides of nitrogen (NOx).
Recommended Content
Authors
- Alberto Ayala - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Michael E. Gebel - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Robert A. Okamoto - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Paul L. Rieger - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Norman Y. Kado - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Cherie Cotter - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
- Namita Verma - California Environmental Protection Agency, Air Resources Board Sacramento and El Monte, CA
Topic
Citation
Ayala, A., Gebel, M., Okamoto, R., Rieger, P. et al., "Oxidation Catalyst Effect on CNG Transit Bus Emissions," SAE Technical Paper 2003-01-1900, 2003, https://doi.org/10.4271/2003-01-1900.Also In
References
- Ayala, A. Kado N. Okamoto R. Gebel M. Rieger P. Holmén B.A. “ARB's Study of Emissions from Diesel and CNG Heavy-duty Transit Buses,” 8 th Diesel Engine Emissions Reduction Conference San Diego Aug. 25-29 2002
- Holmén, B.A. Ayala A. ‘Ultrafine PM Emissions from Natural Gas, Oxidation-Catalyst Diesel and Particulate-Trap Diesel Heavy-Duty Transit Buses,” Environ. Sci. Technol. 2002 36 5041 5050
- Kado, N.Y. Okamoto R.A. Kuzmicky P.A. Kobayashi R. Ayala A. Gebel M.E. Rieger P.L. Maddox C. Zafonte L. “Chemical and Bioassay Analyses of Toxic Pollutant Emissions from Compressed Natural Gas (CNG) and Ultra Low Sulfur Diesel-Fueled Heavy-Duty Transit Buses: Tests Over Multiple Duty Cycles,” Environ. Sci. Technol. 2003 Submitted for review
- California Environmental Protection Agency Air Resources Board Diesel Risk Reduction Plan Approved Document 2000 http://www.arb.ca.gov/diesel/dieselrrp.htm
- Staff Report, Proposed Rule 1192 - Clean On-Road Transit Buses South Coast Air Quality Management District June 2000
- Gibbs, R. “Un-Regulated Emissions from CRT-Equipped Transit Buses,” 6 th Diesel Engine Emissions Reduction Conference San Diego Aug. 20-24 2000
- Zhu, X. Durbin T.D. Norbeck J.M. “Fuel Effects on Volatile Organic Emissions from Medium-Duty Diesel Powered Vehicles,” 12 th CRC On-road Vehicle Emissions Workshop San Diego April 15-17 2002
- Clark, N. N. Gautam M. Rapp B. L. Lyons D. W. Graboski M. S. McCormick R. L. Alleman T. L. Norton P. “Diesel and CNG Transit Bus Emissions Characterization By Two Chassis Dynamometer Laboratories: Results and Issues,” SAE Tech. Paper 1999 1999-01-1469
- Johnson, T.V. “Diesel Emission Control in Review,” SAE Tech. Paper 2001 2001-01-0184
- Ayala, A. Kado N.Y. Okamoto R.A. Holmén B.A. Kuzmicky P.A. Kobayashi R. Stiglitz K.E. “Diesel and CNG Heavy-duty Transit Bus Emissions over Multiple Driving Schedules: Regulated Pollutants and Project Overview,” SAE Tech. Paper 2002 2002-01-1722
- 1998
- Graboski, M.S. McCormick, R.L. Newlin, A.W. Dunnuck, D.L. Kamel, M.M. Ingle, W.D. “Effect of Fuel Composition and Altitude on Regulated Emissions from a Lean-Burn, Closed Loop Controlled Natural Gas Engine,” SAE Tech. Paper 1997 971707
- Air Resources Board www.arb.ca.gov/testmeth/slb/exhaust.htm
- Kado, N. Y. Okamoto R. A. Karim J. Kuzmicky P. A. “Airborne Particle Emissions from 2- and 4-Stroke Outboard Marine Engines: Polycyclic Aromatic Hydrocarbon and Bioassay Analyses,” Environ. Sci. Technol. 2000 34 13 2714 2720
- Holmén, B.A. Ayala A. “Oxidation Catalyst Effects on Natural Gas Transit bus Ultrafine Particle Emissions,” 6 th International ETH Conference on Nanoparticle Measurements Zurich Aug. 19-21 2002
- Clark, N. N. Gadapati, C. J. Kelly, K. White, C. L. Lyons, D. W. Wang, W. Gautam, M. Bata, R. “Comparative Emissions from Natural Gas and Diesel Buses,” SAE Tech. Paper 1995 952746
- Bevilacqua, O. M. “Natural Gas Fuel Composition on Tailpipe Emissions and Fuel Economy” ARB Public Workshop on Alternative Fuels regulations Sacramento, CA June 21 2000
- Traver, M.L. “Interlaboratory Crosscheck of Heavy-Duty Vehicle Chassis Dynamometers,” Final Report Coordinating Research Council, Inc. May 2002