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NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable.

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Presentation on theme: "NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable."— Presentation transcript:

1 NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC. Review and Evaluation of Studies on the Use of E15 in Light-Duty Vehicles Iowa RFA Summit Matthew Ratcliff, Robert L. McCormick, Janet Yanowitz, Bradley T. Zigler January 28, 2014

2 2 E15 Waiver EPA has granted a waiver for the use of E15 in 2001 and newer light-duty cars o October 2010 waiver for 2007 and newer o January 2011 waiver for

3 3 What’s so special about 2001? National low emission vehicle (NLEV) standards (2001) and Tier 2 emission standards (2004) –More sophisticated emission control systems –CAP2000 requires actual in-use vehicle testing over full useful life Improved compensation for fuel oxygen content –Prevents high temperature excursions at full load operation –Protects engine and catalyst from higher levels of oxygen in fuel λ (lambda)

4 4 Scope of Review Objective: o Review and evaluate research on the effects of E15 on 2001 and newer vehicles o Draw robust conclusions based on the entire available dataset Reviewed 43 studies o 33 unique research studies o 10 studies of methodology, reviews, or same data as other studies o More studies on E20 than E15, E20 studies included Primarily conducted by: o USDOE –Oak Ridge National Laboratory –National Renewable Energy Laboratory o Minnesota Center for Automotive Research o Coordinating Research Council –Auto and oil company consortium

5 5 Limitations of the Data Studies are not large enough to make quantitative predictions of potential equipment failure rates o Including CRC engine durability study o Largest studies of whole vehicles (U. of Minnesota and USDOE) found no fuel-related issues Wide variety of control fluids and unique test protocols o Difficult to combine studies into a single analysis Test fuels versus test fluids o Test fuels use commercial ethanol and hydrocarbon, typically meet ASTM D4814 o Test fluids –Contain “aggressive” components –Do not meet fuel quality standards –Not intended for comparison of effects of different fuels because effects of aggressive test fluids relative to real world fuels are unknown

6 6 Overall Conclusions 2001 and newer cars compensate adequately for higher ethanol content o No difference in emissions or catalyst durability for E10 compared to E15 o Combustion and exhaust temperatures not significantly changed Materials studies show little difference in effects of E10 and E15 o Effect of going from E0 to E10 is much larger Fuel system, engine, and whole-vehicle durability studies, taken together, confirm expectations from emissions and materials studies The use of E15 is likely to have little impact on 2001 and newer model year vehicles

7 7 Emissions and Catalyst Durability Studies Sophisticated air/fuel ratio control produces little or no change in NOx or NMOG Fuel oxygen lowers unburned hydrocarbons and CO (mostly during open loop operation) Full useful life catalyst durability tests showed no difference in catalyst degradation for E15 vs. E0 o Strongly implies that engine and exhaust temperatures are not significantly changed These results (and other studies) show that engines compensate for fuel ethanol content

8 8 Materials Compatibility Summary Studies used aggressive test fluids – not intended for comparison to fuel effects Metal corrosion rates very low Minimal differences in elastomer swell between E10 and E17 o Significantly larger differences between E0 and E10 o Differences between materials much larger than differences between fuels

9 9 CRC Fuel System Component Testing 2 Fuel Dampers 10 Fuel Pumps 7 Entire Fuel System Rigs 10 Level Senders 3 Fuel Injectors AVFL 15 Using Aggressive E20 Test Fluid Soak Hot Soak 49 Weeks Soak & Endurance Aging Soak and Full Sweep Aging 600 million cycles 3 Level Senders 4 Fuel Pumps Soak and Full Sweep Soak & Endurance Aging 1 Fuel Pump Choose Most Fluid Sensitive Parts Find Parts Which Fail on E15 but not on E10 AVFL 15a Using Aggressive and non Aggressive Test Fluids But, this pump did not fail on longer testing with Aggressive E20 Test Fluid in AVFL15

10 10 CRC Engine Durability Study CRC Study of 8 engine models ( ) Engines removed from vehicles o Tested for 500 hr on drive cycle intended to simulate 100,000 mi o Tested on E20, if failing, tested on E15, if failing tested on E0 o Statistical analysis assumed passing result for engines not tested Failure criteria: o E = Emissions during EOT FTP75 testing o D = Diagnostic Trouble Code detected at EOT o V = Valve clearance measurement on at least one valve out of OEM specification at EOT o C = Compression measurement on at least one cylinder out of OEM specification at EOT o L = Leakage measurement on at least one cylinder above 10% at EOT Drive cycle engine speeds are too low to rotate valves (<3500 rpm) No E10 control testing Older vehicles well beyond full useful life at EOT Use of dummy data in statistical analysis biases results and makes error bars artificially smaller Inappropriate use of leakdown, typical shop manual criterion is 20-25%

11 11 Concluded that two popular engines used in model year vehicles experienced mechanical failure when operated on E15 CRC Engine Durability Results One vehicle failed leakdown and compression on all fuels, suggesting that engine speeds were too low Leakdown failures inconsistent with industry practice and shop manuals Failure on emissions potentially beyond full useful life If all actual test results (i.e. including Vehicle 8 and excluding dummy data) are used for the analysis, there is a 32% chance that E15 and E20 failures are completely unrelated to ethanol content, as opposed to the 7% chance that is asserted in CRC’s report.

12 12 MnCAR Fuel System Study Tested fuel pumps and fuel level senders using Reference Fuel C, Aggressive TF10 and Aggressive TF20 o Targeted a “broad sample of high volume vehicles on the road” o 4000 hr soak and endurance tests All modern vehicle fuel pumps showed minimal effect of E20 All level sending units failed over the course of the study – on all fuels

13 13 University of Minnesota Fleet Study In use vehicle study 40 pairs (80 total) of similar 2000 to 2006 model year vehicles with matched usage patterns One fueled with commercially available E0, the second fueled with E20 Over the 13 month test period no additional fuel related maintenance problems emerged in the E20 fueled vehicles

14 14 Overall Conclusions 2001 and newer cars compensate adequately for higher ethanol content o No difference in emissions or catalyst durability effect for E10 and E15 o Combustion and exhaust temperatures not significantly changed Materials studies show little difference in effects of E10 and E15 o Effect of going from E0 to E10 is much larger Fuel system, engine, and whole-vehicle durability studies, taken together, confirm expectations from emissions and materials studies The use of E15 is likely to have little impact on 2001 and newer model year vehicles

15 The authors thank RFA for sponsoring this study: ethanolrfa.org

16 16 Acquire 2-4 “matched” vehicles for each model, 1 matched vehicle dedicated to each fuel (E0, E10, E15, or E20) for aging Baseline Emissions (E0) Baseline Emissions (E0) Baseline Emissions (E0) Baseline Emissions (E0) Baseline Emissions (E10) Baseline Emissions (E15) Baseline Emissions (E20) Age on dedicated fuel using MAD or Test Track 25,000 to 50,000 miles Intermediate Emissions (E0) Intermediate Emissions (E0) Intermediate Emissions (E0) Intermediate Emissions (E0) Intermediate Emissions (E10) Intermediate Emissions (E15) Intermediate Emissions (E20) Age on dedicated fuel using MAD or Test Track 25,000 to 50,000 miles Full-Life Emissions (E0) Full-Life Emissions (E10) Full-Life Emissions (E15) Full-Life Emissions (E20) Full-Life Emissions (E0) Full-Life Emissions (E0) Full-Life Emissions (E0) USDOE Catalyst Durability Study

17 17 Vehicle Aging: 82 Vehicles Tested at 3 Sites 58 Tier 2 (19 models), 24 non-Tier 2 (8 models) 35 Vehicles 33 Vehicles 14 Vehicles Non-Tier 2 Vehicles Totals USDOE Catalyst Durability Study

18 18 Catalyst Durability Overview and Conclusions 82 vehicles aged for at least 50,000 miles (many >100,000 miles) o EPA’s Standard Road Cycle o Demonstrate if a new fuel will cause or contribute to the degradation of a vehicle’s emission controls Several had over 90,000 miles at beginning of test and greatly exceeded 120,000 mile full useful life at end of test Of twenty-five 2001 and newer vehicle models, only five were tested on E10 No discernible differences in the rates of catalyst performance degradation between E0 and the ethanol blended fuels

19 19 Vehicles for Engine Durability


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