On knocking combustion development of oxygenated gasoline fuels in a cooperative fuel research engine

Han, Dong; Lyu, Delin; Sun, Zhen; Liang, Xin; Huang, Zhen

doi:10.1177/14680874221118973

Cited by 6 publications

(3 citation statements)

References 29 publications

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“…This method results in an offset with the fuel's ASTM RON number. This offset, although unwanted, is to be expected since the oscillation behaviours of oxygenated fuels like E10 or E05 are known to be different than those of paraffinic fuels [14,18].…”

Section: Experimental Uncertainty Analysismentioning

confidence: 99%

A Pressure-Oscillation-Based RON Estimation Method for Spark Ignition Fuels beyond RON 100

Robeyn,

Sileghem,

Larsson

et al. 2024

Energies

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Knock in spark ignition (SI) engines occurs when the air–fuel mixture in the combustion chamber ignites spontaneously ahead of the flame front, reducing combustion efficiency and possibly leading to engine damage if left unattended. The use of knock sensors to prevent it is common practice in modern engines. Another measure to mitigate knock is the use of higher-octane fuels. The American Society for Testing and Materials’ (ASTM) determination of the Research Octane Number (RON) and Motor Octane Number (MON) of spark ignition fuels has been based on measuring cylinder pressure rise at the onset of knock since its inception in the 1930s. This is achieved through a low-pass filtered pressure signal. Knock detection in contemporary engines, however, relies on measuring engine vibrations caused by high-frequency pressure oscillations during knock. The difference between conditions in which fuels are evaluated for their octane rating and the conditions that generate a knock intensity signal from the knock sensor suggests a potential difference between octane rating and the knock limit typically identified by a contemporary knock sensor. To address this disparity, a modified RON measurement method has been developed, incorporating pressure oscillation measurements. This test method addresses the historical lack of correlation between RON and high-frequency pressure oscillation intensity during knock. Using toluene standardization fuels (TSFs) as a reference, the obtained results demonstrate excellent high-frequency knock intensity-based RON estimations for gasoline. The method is able to differentiate between two fuels that share the same ASTM RON, associating them with a RON-like metric that is more aligned with their performance in a modern SI engine. This alternative method could potentially serve as a template for an upgrade to the existing ASTM RON method without significantly disrupting the current approach. Additionally, its capability to evaluate fuels beyond RON 100 opens the door to assessing a wider range of fuels for antiknock properties and the intensity of fuel oscillations during knocking combustion.

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Section: Experimental Uncertainty Analysismentioning

confidence: 99%

A Pressure-Oscillation-Based RON Estimation Method for Spark Ignition Fuels beyond RON 100

Robeyn,

Sileghem,

Larsson

et al. 2024

Energies

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“…Due to its relatively high H/C ratio, n -hexadecane shows satisfactory combustion performance . Alcohol additives are applied to improve fuel capacities, such as combustion efficiency, − environmental friendliness, , and the amount of coking . As a renewable substance, 1-butanol has properties such as low volatility and good oil solubility .…”

Section: Introductionmentioning

confidence: 99%

Densities and Viscosities of the Ternary Mixtures of Decalin (1) + n-Hexadecane (2) + 1-Butanol (3) and Corresponding Binary Systems

Yao

Jiang

et al. 2023

J. Chem. Eng. Data

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Active cooling by endothermic hydrocarbon fuels (EHFs) is considered as a practical approach to deal with the thermal management problem of hypersonic aircrafts. As a typical component of EHFs, decalin is usually thermally stable while it is apt to coke and has poor combustion performance. n-Hexadecane, a normal alkane with a relatively high H/C ratio, can effectively improve the combustion performance of EHFs, and 1-butanol has remarkable anticoking properties. As a fundamental work for fuel design, decalin, n-hexadecane, and 1-butanol were selected as model compounds to construct a surrogate fuel system, which was used to investigate the effects of composition and condition on its thermophysical properties. Densities (ρ) and viscosities (η) of the ternary system of decalin (1) + n-hexadecane (2) + 1-butanol (3) and corresponding binary systems were measured at temperatures T = (293.15 to 333.15) K and pressure p = 0.1 MPa. The excess molar volumes (V m E ) and the viscosity deviations (Δη) of the mixtures were calculated and fitted to several semi-empirical equations. The tendencies of V m E and Δη with composition and temperature were discussed from intermolecular force and molecular size, respectively.

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“…Both the above studies 14,15 employed simplified geometries of the CFR engine, without incorporating key features, such as the intake valve shroud, spark plug cavity, and knock meter port cavity. Han et al 16 also performed closed single cycle 3-D CFD simulations of the CFR engine at RON and MON relevant conditions for PRF/alcohol blends.…”

Section: Introductionmentioning

confidence: 99%

Fuel-air mixing in motored CFR engine at research octane number (RON) relevant condition

Bhattacharya,

Keskinen,

Larmi

et al. 2023

International Journal of Engine Research

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This paper presents a three-dimensional (3-D) computational fluid dynamics (CFD) study of a motored cooperative fuel research (CFR) engine at research octane number (RON) relevant condition. The boundary conditions for 3-D simulations were generated with a one-dimensional GT-Power model. For the first time in literature, a carburetor was added to a virtual CFR engine model with 3-D CFD. Therefore, the proposed setup can simulate the fuel and thermal stratifications inside the engine cylinder with realistic detail. The transient simulations in this work were performed within the Reynolds-averaged Navier-Stokes (RANS) framework with a Realizable k-ε turbulence model. Major conclusions from the present work are: (1) The in-cylinder flow of the CFR engine is swirl-dominated due to the existence of the intake valve shroud. (2) There is a significant amount of liquid droplets entering the cylinder during the intake stroke. The maximum instantaneous amount of liquid for 50% PRF 87 (containing 87% iso-octane and 13% n-heptane (v/v)) and 50% ethanol mixture is indicated to be around 26% of total injected fuel mass. (3) The heat of vaporization (HoV) of the fuel is responsible for creating both temperature and charge stratification inside the cylinder.

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On knocking combustion development of oxygenated gasoline fuels in a cooperative fuel research engine

Cited by 6 publications

References 29 publications

A Pressure-Oscillation-Based RON Estimation Method for Spark Ignition Fuels beyond RON 100

A Pressure-Oscillation-Based RON Estimation Method for Spark Ignition Fuels beyond RON 100

Densities and Viscosities of the Ternary Mixtures of Decalin (1) + n-Hexadecane (2) + 1-Butanol (3) and Corresponding Binary Systems

Fuel-air mixing in motored CFR engine at research octane number (RON) relevant condition

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