| Title: | Regulated and unregulated emissions from highway heavy-duty diesel engines complying with U.S. Environmental Protection Agency 2007 emissions standards |
| Author(s): | Khalek IA; Bougher TL; Merritt PM; Zielinska B; |
| Address: | "Department of Emissions R&D, Southwest Research Institute, San Antonio, TX 78238, USA. lkhalek@swri.org" |
| DOI: | 10.3155/1047-3289.61.4.427 |
| ISSN/ISBN: | 1096-2247 (Print) 1096-2247 (Linking) |
| Abstract: | "As part of the Advanced Collaborative Emissions Study (ACES), regulated and unregulated exhaust emissions from four different 2007 model year U.S. Environmental Protection Agency (EPA)-compliant heavy-duty highway diesel engines were measured on an engine dynamometer. The engines were equipped with exhaust high-efficiency catalyzed diesel particle filters (C-DPFs) that are actively regenerated or cleaned using the engine control module. Regulated emissions of carbon monoxide, nonmethane hydrocarbons, and particulate matter (PM) were on average 97, 89, and 86% lower than the 2007 EPA standard, respectively, and oxides of nitrogen (NOx) were on average 9% lower. Unregulated exhaust emissions of nitrogen dioxide (NO2) emissions were on, average 1.3 and 2.8 times higher than the NO, emissions reported in previous work using 1998- and 2004-technology engines, respectively. However, compared with other work performed on 1994- to 2004-technology engines, average emission reductions in the range of 71-99% were observed for a very comprehensive list of unregulated engine exhaust pollutants and air toxic contaminants that included metals and other elements, elemental carbon (EC), inorganic ions, and gas- and particle-phase volatile and semi-volatile organic carbon (OC) compounds. The low PM mass emitted from the 2007 technology ACES engines was composed mainly of sulfate (53%) and OC (30%), with a small fraction of EC (13%) and metals and other elements (4%). The fraction of EC is expected to remain small, regardless of engine operation, because of the presence of the high-efficiency C-DPF in the exhaust. This is different from typical PM composition of pre-2007 engines with EC in the range of 10-90%, depending on engine operation. Most of the particles emitted from the 2007 engines were mainly volatile nuclei mode in the sub-30-nm size range. An increase in volatile nanoparticles was observed during C-DPF active regeneration, during which the observed particle number was similar to that observed in emissions of pre-2007 engines. However, on average, when combining engine operation with and without active regeneration events, particle number emissions with the 2007 engines were 90% lower than the particle number emitted from a 2004-technology engine tested in an earlier program" |
| Keywords: | "Air Pollution/analysis/legislation & jurisprudence Carbon Monoxide/analysis Gasoline/standards Lubrication Nitrogen Dioxide/analysis Oxidants, Photochemical/analysis Particle Size Particulate Matter Polycyclic Aromatic Hydrocarbons/analysis United States;" |
| Notes: | "MedlineKhalek, Imad A Bougher, Thomas L Merritt, Patrick M Zielinska, Barbara eng Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S. 2011/04/27 J Air Waste Manag Assoc. 2011 Apr; 61(4):427-42. doi: 10.3155/1047-3289.61.4.427" |
