Abstract
Gasoline knock resistance is characterized by the Research and Motor Octane Number (RON and MON), which are rated on the CFR octane rating engine at naturally aspirated conditions. However, modern automotive downsized boosted spark ignition (SI) engines generally operate at higher cylinder pressures and lower temperatures relative to the RON and MON tests. Using the naturally aspirated RON and MON ratings, the octane index (OI) characterizes the knock resistance of gasolines under boosted operation by linearly extrapolating into boosted "beyond RON"conditions via RON, MON, and a linear regression K factor. Using OI solely based on naturally aspirated RON and MON tests to extrapolate into boosted conditions can lead to significant errors in predicting boosted knock resistance between gasolines due to non-linear changes in autoignition and knocking characteristics with increasing pressure conditions. A new "Supercharged Octane Number"(SON) method was developed on the CFR engine at increased intake pressures, which improved the correlation to boosted knock-limited automotive SI engine data over RON for several surrogate fuels and gasolines, including five "Co-Optima"RON 98 fuels and an E10 regular grade gasoline. Furthermore, the conventional OI was extended to a newly introduced Supercharged Octane Index (OIS) based on SON and RON, which significantly improved the correlation to fuel knock resistance measurements from modern boosted SI engine knock-limited spark advance tests. This demonstrated the first proof of concept of a SON and OIS to better characterize a fuel's knock resistance in modern boosted SI engines.
Original language | English |
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Journal | SAE Technical Papers |
DOIs | |
State | Published - Apr 11 2023 |
Event | SAE 2023 World Congress Experience, WCX 2023 - Detroit, United States Duration: Apr 18 2023 → Apr 20 2023 |
Funding
The submitted manuscript has been created in part by UChicago Argonne, LLC, Operator of Argonne National Laboratory (“Argonne”) and Oak Ridge National Laboratory (“ORNL”). Argonne, a U.S. Department of Energy Office of Science laboratory, is operated under Contract No. DE-AC02-06CH11357 and ORNL is a U.S. Department of Energy Office of Science laboratory managed by UT-Battelle under contract DE-AC05-00OR22725. The U.S. Government retains for itself, and others acting on its behalf, a paid-up nonexclusive, irrevocable worldwide license in said article to reproduce, prepare derivative works, distribute copies to the public, and perform publicly and display publicly, by or on behalf of the Government. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan. http://energy.gov/ downloads/doe-public-access-plan. This work is performed under the auspices of the Office of Energy Efficiency and Renewable Energy, Office of Vehicle Technology, U.S. Department of Energy, as part of the Co-Optimization of Fuels & Engines (Co-Optima) program. Special thanks to the Vehicle Technologies Office program managers Kevin Stork, Gurpreet Singh, Leo Breton, and Mike Weismiller, as well as the Bioenergy Technology Office Program manager Alicia Lindauer.