Effects of methanol-containing additive on emission characteristics from aheavy-duty diesel engine

This study was aimed to investigate the effect of methanol-containing addit ive (MCA) on the regulated emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx), particulate matter (PM), as well as the unregu lated carbon dioxide (CO2) and polycyclic aromatic hydrocarbons (PAHs) from a diesel engine. The engine was tested on a series of diesel fuels blended with five additive levels (0, 5, 8, 10 and 15% of MCA by volume). Emission s tests were performed under both cold- and hot-start transient heavy-duty federal test procedure (HD-FTP) cycles and two selected steady-state modes. Results show that MCA addition slightly decreases PM emissions but general ly increases both THC and CO emissions. Decrease in NO, emissions was found common in all MCA blends. As for unregulated emissions, CO2 emissions did not change significantly for all MCA blends, while vapor-phase and particle -associated PAHs emissions in high load and transient cycle tests were rela tively low compared to the base diesel when either 5 or 8% MCA was used. Th is may be attributed to the lower PAHs levels in MCA blends. Finally, the p article-associated PAHs emissions also showed trends quite similar to that of the PM emissions in this study. (C) 2001 Elsevier Science B.V. All right s reserved.