Potential Impacts of High-Octane Fuel Introduction in a Naturally Aspirated, Port Fuel-Injected Legacy Vehicle
Technical Paper
2020-01-5117
ISSN: 0148-7191, e-ISSN: 2688-3627
Sector:
Event:
Automotive Technical Papers
Language:
English
Abstract
In recent years there has been an increased interest in raising the octane level of gasoline to enable higher compression ratios (CR) in spark-ignition engines to improve vehicle fuel efficiency. A number of studies have examined opportunities to increase efficiency in future vehicles, but potential impacts on the legacy fleet have not received as much attention. This effort focused on experimental studies on an engine using high-octane fuels without changing the engine’s CR. Spark timing was advanced until maximum torque was reached or knock was encountered for each engine condition, using each individual fuel to maximize engine efficiency. Knock-limited conditions occurred as the output brake mean effective pressure (BMEP) neared the maximum attainable output at a given engine speed. Increasing research octane numbers generally enabled knock-free operation under a greater number of operating conditions. Vehicle modeling using Autonomie was used to project vehicle energy use, fuel economy, and tailpipe CO2 emissions for the Urban Dynamometer Driving Schedule (UDDS), the Highway Fuel Economy Test (HWFET), and the US06 cycle. Results show that decreases in energy consumption of up to 2% for a small SUV are possible through the use of a 97 RON fuel compared to a baseline using 91 RON fuel, provided that the formulation of the fuel does not cause unanticipated operational issues such as lower maximum BMEP. Greater improvements using high-octane fuels are possible if the CR is increased, but there is no opportunity to increase the CR in legacy vehicles. Thus, these vehicles realize an improvement from increased octane rating in accordance with their ability to spark advance to take advantage of a fuel with a higher octane rating. For the modeled vehicle, improvements of up to 2% in volumetric fuel economy may be possible through the use of a 97 RON fuel with the largest gains expected on the US06 cycle. Fuel economy impacts are strongly coupled to the heating value of the fuels in addition to changes in engine efficiency. Similarly, decreases in tailpipe CO2 emissions are also achievable. However, simultaneous improvements in energy consumption, fuel economy, and tailpipe CO2 emissions are not guaranteed and are dependent upon fuel formulation.
Topic
Citation
Sluder, S. and Perry, N., "Potential Impacts of High-Octane Fuel Introduction in a Naturally Aspirated, Port Fuel-Injected Legacy Vehicle," SAE Technical Paper 2020-01-5117, 2020, https://doi.org/10.4271/2020-01-5117.Data Sets - Support Documents
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References
- Leone, T.G., Anderson, J.E., Davis, R.S., Iqbal, A. et al. , “The Effect of Compression Ratio, Fuel Octane Rating, and Ethanol Content on Spark-Ignition Engine Efficiency,” Environ. Sci. Technol. 49:10778-10789, 2015, https://doi.org/10.1021/acs.est.5b01420.
- Sluder, C., Smith, D., Wissink, M., Anderson, J. et al. , “Effects of Octane Number, Sensitivity, Ethanol Content, and Engine Compression Ratio on GTDI Engine Efficiency, Fuel Economy, and CO2 Emissions,” Report# AVFL-20, Coordinating Research Council, Nov. 2017.
- Smith, P., Heywood, J., and Cheng, W. , “Effects of Compression Ratio on Spark-Ignited Engine Efficiency,” SAE Technical Paper 2014-01-2599, 2014, https://doi.org/10.4271/2014-01-2599.
- Chow, E., Heywood, J., and Speth, R. , “Benefits of a Higher Octane Standard Gasoline for the U.S. Light-Duty Vehicle Fleet,” SAE Technical Paper 2014-01-1961, 2014, https://doi.org/10.4271/2014-01-1961.
- Leach, B.P.R. and Williams, J. , “CO2 Emission Reduction Synergies of Advanced Engine Design and Fuel Octane Number,” SAE Technical Paper 2014-01-2610, 2014, https://doi.org/10.4271/2014-01-2610.
- West, B.H., Sluder, C.S., and Smith, D.E. , “An Engine and Modelling Study on Potential Fuel Efficiency Benefits of a High-Octane E25 Gasoline Blend,” ORNL/TM-2017/357, 2017.
- Leone, T., Oline, E., Anderson, J., Jung, H. et al. , “Effects of Fuel Octane Rating and Ethanol Content on Knock, Fuel Economy, and CO2 for a Turbocharged DI Engine,” SAE Int. J. Fuels Lubr. 7(1):9-28, 2014, https://doi.org/10.4271/2014-01-1228.
- Sluder, C., Smith, D., Anderson, J., Leone, T. et al. , “U.S. DRIVE Fuels Working Group Engine and Vehicle Modeling Study to Support Life-Cycle Analysis of High-Octane Fuels,” U.S. Department of Energy, 2019.
- Davis, S.C. and Boundy, R.G. , Transportation Energy Data Book 38th Edition (Oak Ridge: Oak Ridge National Laboratory, 2020).
- Phlips, P. , “SI Engine Model for Vehicle Fuel Consumption Estimation,” in FISITA World Automotive Congress, F2014-CET-140, 2014.
- Ross, M. and An, F. , “The Use of Fuel by Spark Ignition Engines,” SAE Technical Paper 930329, 1993, https://doi.org/10.4271/930329.
- Shayler, P., Chick, J., and Eade, D. , “A Method of Predicting Brake Specific Fuel Consumption Maps,” SAE Technical Paper 1999-01-0556, 1999, https://doi.org/10.4271/1999-01-0556.
- Phlips, P. , “Analytic Engine and Transmission Models for Vehicle Fuel Consumption Estimation,” SAE Int. J. Fuels Lubr. 8(2):423-440, 2015, https://doi.org/10.4271/2015-01-0981.
- Jung, H., Shelby, M., Newman, C., and Stein, R. , “Effect of Ethanol on Part Load Thermal Efficiency and CO2 Emissions of SI Engines,” SAE Int. J. Engines 6(1):456-469, 2013, https://doi.org/10.4271/2013-01-1634.
- United States Environmental Protection Agency , “EPA Letter to Manufacturers, VPCD-97-01,” 1997.