Correlation of Low Temperature Heat Release With Fuel Composition and HCCI Engine Combustion

Shibata, Gen; Oyama, Koji; Urushihara, Tomonori; Nakano, Tsuyoshi

doi:10.4271/2005-01-0138

Cited by 118 publications

(72 citation statements)

References 9 publications

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“…Octane index [19,20,21], Shibata correlation [22,23], and the Lund-Chevron number [24] have been previously proposed to replace RON/MON for HCCI engine combustion. The effect of adding an octane booster can be better understood in terms of the blending octane number [25].…”

Section: Introductionmentioning

confidence: 99%

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Singh¹,

Waqas²,

Johansson³

et al. 2017

SAE Technical Paper Series

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The blending of ethanol with primary reference fuel (PRF) mixtures comprising n-heptane and iso-octane is known to exhibit a non-linear octane response; however, the underlying chemistry and intermolecular interactions are poorly understood. Well-designed experiments and numerical simulations are required to understand these blending effects and the chemical kinetic phenomenon responsible for them. To this end, HCCI engine experiments were previously performed at four different conditions of intake temperature and engine speed for various PRF/ethanol mixtures. Transfer functions were developed in the HCCI engine to relate PRF mixture composition to autoignition tendency at various compression ratios. The HCCI blending octane number (BON) was determined for mixtures of 2-20 vol % ethanol with PRF70. In the present work, the experimental conditions were considered to perform zerodimensional HCCI engine simulations with detailed chemical kinetics for ethanol/PRF blends. The simulations used the actual engine geometry and estimated intake valve closure conditions to replicate the experimentally measured start of combustion (SOC) for various PRF mixtures. The simulated HCCI heat release profiles were shown to reproduce the experimentally observed trends, specifically on the effectiveness of ethanol as a low temperature chemistry inhibitor at various concentrations. Detailed analysis of simulated heat release profiles and the evolution of important radical intermediates (e.g., OH and HO 2 ) were used to show the effect of ethanol blending on controlling reactivity. A strong coupling between the low temperature oxidation reactions of ethanol and those of n-heptane and iso-octane is shown to be responsible for the observed blending effects of ethanol/PRF mixtures.

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Section: Introductionmentioning

confidence: 99%

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Singh¹,

Waqas²,

Johansson³

et al. 2017

SAE Technical Paper Series

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“…[12][13][14][15][16][17] The most common clean-combustion techniques under consideration are homogeneous charge compression ignition (HCCI) and lowtemperature combustion (LTC); both involve modifications to the air-fuel mixture, ignition timing, air charge boost pressures, and percentage of exhaust gas recirculation (EGR) in the charge air. The goal of each of these technologies is to improve the engine thermal efficiency while minimizing unwanted exhaust compounds such as NO x and particulate matter (PM/soot).…”

Section: Powertrain Materialsmentioning

confidence: 99%

Road Transportation Vehicles

et al. 2008

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In many industrial countries, road transportation accounts for a significant portion of the country's energy consumption. In developing countries, the use of energy for transportation is on the rise. The recent increase in petroleum prices, expanding world economic prosperity, the probable peaking of conventional petroleum production in the coming decades, and concerns about global climate changes require efforts to increase the efficiency of the use of, and develop alternatives for, petroleum-based fuels used in road transportation. The energy efficiency of a vehicle could be improved in several ways: lightweighting the vehicle structure and powertrain using advanced materials and designs, improving the efficiency of the internal combustion engine, reducing tire rolling resistance, and hybridization. Each of these efforts will require improvements in materials and processes.

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“…This is the result of the easier H-atom abstraction of the allylic hydrogens [20], Table 7. Olefin effect on HC emissions at 1500 rpm.…”

Section: Discussionmentioning

confidence: 99%

Homogeneous Charge Compression Ignition: Formulation Effect of a Diesel Fuel on the Initiation and the Combustion - Potential of Olefin Impact in a Diesel Base Fuel

Alseda

Montagne

Dagaut

2008

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Combustion en mode HCCI : impact de la formulation d'un carburant Diesel sur l'initiation et la combustion -Potentiel de l'ajout d'oléfine dans une base gazole -L'objectif de ce travail est de proposer une amélioration du contrôle et de l'initiation de la combustion en mode HCCI via la formulation du carburant. L'article présente l'impact de l'addition d'oléfines (et en particulier l'addition de 1-octène et d'octa-1,7-diène) dans une base gazole. Les tests sont effectués à l'aide d'un réacteur auto-agité et d'un banc moteur. L'indice de cétane d'un carburant Diesel n'est pas réellement adapté pour un contrôle parfait de la combustion en mode HCCI. Dans des conditions de combustion en mode HCCI, l'autoinflammation de la base gazole se produit trop tôt dans le cycle moteur. Cette étude montre, sur réacteur auto-agité, que le 1-octène réduit l'avancement réactionnel de la flamme froide du n-octane. Sur banc moteur, à 1500 tr/min, l'ajout de 1-octène et d'octa-1,7-diène diminue le délai physique et augmente le délai chimique d'auto-inflammation de la base gazole. Ces résultats s'expliquent par la chimie des oléfines : les doubles liaisons des oléfines impliquent des réactions compétitives (avec des radicaux) à celles donnant lieu à la flamme froide. De plus, les espèces intermédiaires sont stabilisées par mésomérie. Au niveau des polluants, les oléfines diminuent les émissions d'HC de la base gazole. Ajouter des oléfines légères à une base gazole est une voie d'amélioration envisageable pour la combustion en mode HCCI. Abstract -Homogeneous Charge Compression Ignition: Formulation Effect of a Diesel Fuel on the Initiation and the Combustion -Potential of Olefin Impact in a DieselBase Fuel -In this work, attention is paid on initiation and HCCI combustion control through fuel formulation. This article shows the effect of olefin addition (and in particular 1-octene and octa-1,7-diene addition) in a Diesel base fuel. Tests are made with a jet-stirred reactor and an engine bench. The current Diesel fuel cetane numbers are not really adapted for a perfect control of HCCI combustion. In HCCI conditions, the autoignition of a Diesel fuel occurs too early in the cycle. This study shows that, with the jet-stirred reactor, 1-octene addition allows decreasing the advancement of the cool flame reaction of n-octane. Engine bench experiments show that, at 1500 rpm, 1-octene and octa-1,7-diene addition decrease the physical delay and increase the chemical auto-ignition delay of the Diesel base fuel. These results can be explained by olefin chemistry: olefin double bonds imply reactions (with radicals) that are in competition with the cool flame reactions. There is also the fact that the intermediate species are stabilised by mesomery. About pollutants, olefin addition decreases HC emissions of the Diesel base fuel. Adding light olefins in a Diesel base fuel could improving the HCCI combustion.

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Correlation of Low Temperature Heat Release With Fuel Composition and HCCI Engine Combustion

Cited by 118 publications

References 9 publications

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Road Transportation Vehicles

Homogeneous Charge Compression Ignition: Formulation Effect of a Diesel Fuel on the Initiation and the Combustion - Potential of Olefin Impact in a Diesel Base Fuel

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