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原文传递 Impact of E15/E20 Blends on OBDII Systems: Pilot Study.

题名：	Impact of E15/E20 Blends on OBDII Systems: Pilot Study.
作者：	R. Klausmeier;
关键词：	ethanol/gasoline blends,potential impact,in-use vehicles,onboard diagnostic system;ethanol, inspections, maintenance programs;malfunction indicator light(mil)
摘要：	This study examined the potential impact of 15%and 20%ethanol/gasoline blends (E15/E20) on the onboard diagnostic (OBDII) system of in-use vehicles. The goal of this study was to collect and analyze OBDII and related data from in-use vehicles to determine the potential for more frequent malfunction indicator light (MIL) illuminations when a vehicle is fueled with E15 or E20. To meet this goal, researchers identified inspection/maintenance (I/M) programs that were operated in areas where gasoline with no ethanol (E0) and 10%ethanol (E10) was dispensed, then set-up a test program where long-term fuel trim (LTFT) and other parameters were recorded over a 10 minute period after vehicles received their periodic I/M test. It was found that operation on 10%ethanol/gasoline blends (E10) increases LTFT over E0 levels for most vehicles. The sensitivity varies by original equipment manufacturer (OEM), but all OEMs show the trend. The tests conducted in this study provide evidence that operation on 15%or 20%ethanol/gasoline blends (E15 or E20) may cause a subset of problem-free vehicles to illuminate their malfunction indicator light (MIL) due to excessively lean operation. The fraction depends on the assumed LTFT threshold and the fuel ethanol content and is roughly estimated to be of the order of a percent or so. A more precise estimate of this fraction cannot be made with the available data. There is also evidence that operation on E15 and E20 may cause some vehicles that currently have illuminated MILs due to rich operation to appear to be problem free, but no vehicles with this type of illuminated MIL were detected in this program. Additional study is needed to better quantify potential ethanol-related issues with OBD MIL. Vehicle testing on E15 or E20 is needed to confirm that false positive or negative MIL illumination will occur. Further analysis of MIL status from I&M data and more detailed MIL illumination thresholds for different OEMs will also help to better define the scope of this problem. Not ready rates for the evap monitor in Texas were higher in the E10 area than in the E0 area; more data would also be required to determine if ethanol was affecting this parameter. / Title Note: Final rept. / Supplementary Notes: Sponsored by Coordinating Research Council, Inc., Alpharetta, GA. / Availability Note: Order this product from NTIS by: phone at 1-800-553-NTIS (U.S. customers); (703)605-6000 (other countries); fax at (703)605-6900; and email at orders@ntis.gov. NTIS is located at 5301 Shawnee Road, Alexandria, VA, 22312, USA. / NTIS Prices: PC A05 / NTIS In-house Control Codes: crc;12091,1101 &C / Project Number: E-90 / Corporate Author Code: 888888888 / Classifivation: Unclassified report
报告类型：	科技报告