The Shift in Relevance of Fuel RON and MON to Knock Onset in Modern SI Engines Over the Last 70 Years

Mittal, Vikram; Heywood, John B.

doi:10.4271/2009-01-2622

Cited by 92 publications

(57 citation statements)

References 7 publications

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“…Furthermore, for fuels which outperform iso-octane (100 RON) the values can only be extrapolated. As such, the CFR engine octane methods, developed in 1930, have received criticism for their relevance to the modern situation [27,[30][31][32]. Therefore, in an effort to further establish the antiknock performance of DMF, the authors have proposed an alternative method, which is closer to modern reality.…”

Section: Introductionmentioning

confidence: 95%

Ignition timing sensitivities of oxygenated biofuels compared to gasoline in a direct-injection SI engine

Daniel

Tian

et al. 2012

Fuel

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Section: Introductionmentioning

confidence: 95%

Ignition timing sensitivities of oxygenated biofuels compared to gasoline in a direct-injection SI engine

Daniel

Tian

et al. 2012

Fuel

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“…9 RON and MON are used ubiquitously; nevertheless, their application to fuels in modern engines is questionable, as the evolution of automobiles has pushed engine designs and operating conditions further away from the standard RON and MON test conditions. 10 Moreover, the standard tests do have some caveats when using them to test the autoignition tendency of fuels. The standard CFR engine employs a carburetor for fuel-air mixing, which is not the most reliable and accurate method to maintain a stoichiometric air−fuel ratio.…”

Section: Introductionmentioning

confidence: 99%

Chemical Kinetic Insights into the Octane Number and Octane Sensitivity of Gasoline Surrogate Mixtures

2017

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Gasoline octane number is a significant empirical parameter for the optimization and development of internal combustion engines capable of resisting knock. Although extensive databases and blending rules to estimate the octane numbers of mixtures have been developed and the effects of molecular structure on autoignition properties are somewhat understood, a comprehensive theoretical chemistry-based foundation for blending effects of fuels on engine operations is still to be developed. In this study, we present models that correlate the research octane number (RON) and motor octane number (MON) with simulated homogeneous gas-phase ignition delay times of stoichiometric fuel/air mixtures. These correlations attempt to bridge the gap between the fundamental autoignition behavior of the fuel (e.g., its chemistry and how reactivity changes with temperature and pressure) and engine properties such as its knocking behavior in a cooperative fuels research (CFR) engine. The study encompasses a total of 79 hydrocarbon gasoline surrogate mixtures including 11 primary reference fuels (PRF), 43 toluene primary reference fuels (TPRF), and 19 multicomponent (MC) surrogate mixtures. In addition to TPRF mixture components of iso-octane/n-heptane/toluene, MC mixtures, including n-heptane, iso-octane, toluene, 1-hexene, and 1,2,4-trimethylbenzene, were blended and tested to mimic real gasoline sensitivity. ASTM testing protocols D-2699 and D-2700 were used to measure the RON and MON of the MC mixtures in a CFR engine, while the PRF and TPRF mixtures' octane ratings were obtained from the literature. The mixtures cover a RON range of 0−100, with the majority being in the 70−100 range. A parametric simulation study across a temperature range of 650−950 K and pressure range of 15−50 bar was carried out in a constant-volume homogeneous batch reactor to calculate chemical kinetic ignition delay times. Regression tools were utilized to find the conditions at which RON and MON best correlate with simulated ignition delay times. Furthermore, temperature and pressure dependences were investigated for fuels with varying octane sensitivity. This analysis led to the formulation of correlations useful to the definition of surrogates for modeling purposes and allowed one to identify conditions for a more in-depth understanding of the chemical phenomena controlling the antiknock behavior of the fuels.

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“…A secondary aspect was to verify, directly on a modern engine, which index better characterizes the knock resistance of a gasoline and, as a consequence, its impact on the octane requirement of the engine. Similar investigations have been conducted in the last years to exploit these aspects [11,12]. It is well known that the primary index to quantify this characteristic is the RON, determined in the laboratory by using the Cooperative Fuel Research (CFR) engine, under fixed reference conditions.…”

Section: Introductionmentioning

confidence: 94%

Experimental investigations on high octane number gasoline formulations for internal combustion engines

Cerri

D’Errico

Onorati

2013

Fuel

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The Shift in Relevance of Fuel RON and MON to Knock Onset in Modern SI Engines Over the Last 70 Years

Cited by 92 publications

References 7 publications

Ignition timing sensitivities of oxygenated biofuels compared to gasoline in a direct-injection SI engine

Ignition timing sensitivities of oxygenated biofuels compared to gasoline in a direct-injection SI engine

Chemical Kinetic Insights into the Octane Number and Octane Sensitivity of Gasoline Surrogate Mixtures

Experimental investigations on high octane number gasoline formulations for internal combustion engines

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