A comparison of butanol and ethanol flame development in an optical spark ignition engine

Moxey, Ben G.; Cairns, Alasdair; Zhao, Hua

doi:10.1016/j.fuel.2015.12.008

Cited by 23 publications

(8 citation statements)

References 23 publications

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“…When examining in-cylinder pressure data alone, with a sample size of 300 cycles it was generally observed that no single real cycle would exhibit in-cylinder pressure development identical to that of the arithmetic mean pressure profile computed over the data set. This observation is in good agreement with the prior related observations of Moxey [38], [40]. Hence it was crucial to manually select a real cycle whose pressure development was closest to the averaged cycles.…”

Section: Combustion Stability and Cycle Validationsupporting

confidence: 89%

A study of hydrous ethanol combustion in an optical central direct injection spark ignition engine

et al. 2019

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The aim of this experimental work was to improve understanding of the influence of hydrous ethanol on combustion in an engine demonstrating a tendency for biased flame migration towards the hotter exhaust walls as often reported for typical modern pent roof design IC engines. The work aimed to uncover the degree of residual water content that can be reasonably tolerated in terms of combustion characteristics in future ethanol SI engines (with the energy required to reduce water levels then potentially reduced).The experiments were performed in a single cylinder optical research engine equipped with a modern central direct injection combustion chamber and Bowditch type optical piston. Results were obtained under part-load engine operating conditions (selected to represent typical highway cruising conditions) with hydrous ethanol at 5%, 12% and 20% volume water. Baseline results were obtained using pure isooctane. High-speed cross-correlated particle image velocimetry was undertaken at 1500rpm under motoring conditions with the intake plenum pressure set to 0.5 bar absolute. The horizontal imaging plane was fixed 10mm below the combustion chamber "fire face". Comparisons were made to CFD computations of the in-cylinder flow. Complimentary flame images were obtained via the "natural light" (chemiluminescence) technique over multiple engine cycles. The flame images revealed the tendency of an iso-octane fueled flame to migrate towards the exhaust side of the combustion chamber, with no complimentary bulk air motion apparent in this area in the horizontal imaging plane. The faster-burning ethanol offset this tendency of the flame to migrate towards the hotter exhaust walls. The fastest combustion rate occurred with pure ethanol, with higher water content (>5%) generally slowing down the flame speed rate to 10.64 m/s from 10.92 of ethanol and offsetting the flame speed/migration benefit (in good agreement with recent laminar burning velocity correlations for hydrous ethanol). When adding 20% water to ethanol the combustion rate was significantly slower (8.2 m/s) with a considerable increase in flame shape distortion as quantified by flame image shape factor values. The results demonstrate how the added water increases flame distortion and leads to higher flame centre displacement. Such flame centre displacement could potentially be offset in the future with a spark plug location biased further towards the intake side of the chamber (albeit sometimes practically constrained by the priorities given to intake valve sizing and local cooling jacket design). The results indicate that ethanol fuels offset such bias flame growth and allow residual water to be tolerated for an equivalent degree of biased flame migration. The implication is reduced fuel production energy and cost required to produce usable ethanol fuels.

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Section: Combustion Stability and Cycle Validationsupporting

confidence: 89%

A study of hydrous ethanol combustion in an optical central direct injection spark ignition engine

et al. 2019

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View full text Add to dashboard Cite

show abstract

“…When examining in-cylinder pressure data alone, with a sample size of 300 cycles it was generally observed that no single real cycle would exhibit in-cylinder pressure development identical to that of the arithmetic mean pressure profile computed over the data set. This observation is in good agreement with the prior related work of Moxey [9], [30]. Hence it was crucial to manually select a real cycle whose pressure development was closest to the averaged cycles.…”

Section: Cycle Selectionsupporting

confidence: 89%

“…While the lower alcohols have therefore warranted significant interest, "higher" alcohols such as propanol, butanol, and pentanol have also been considered for automotive use, primarily due to their suitability for mixing within the existing gasoline pool. From a thermodynamic stance, higher alcohols generally exhibit higher calorific value (and hence better volumetric fuel consumption), better water tolerance, volatility control and lower Reid vapour pressure [26]- [30]. However, benefits in knock resistance and latent heat are typically reduced.…”

Section: Introductionmentioning

confidence: 99%

Cyclically resolved flame and flow imaging in an alcohol fuelled SI engine

Koupaie

Cairns

Xia

et al. 2019

Fuel

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The work was concerned with improving understanding of the interaction of the bulk in-cylinder flow with turbulent premixed flame propagation when using varied fuels including iso-octane, ethanol or butanol. The experiments were performed in a single cylinder research engine equipped with a modern central direct injection combustion chamber and Bowditch style optical piston.Results were obtained under typical part-load engine operating conditions. High speed cross-correlated particle image velocimetry was undertaken at 1500rpm under motoring conditions with the plenum pressure set to 0.5 bar absolute, with the horizontal imaging plane fixed 10mm below the combustion chamber "fireface". Comparisons were made to CFD computations of the flow.Complementary flame images were then obtained via natural light (chemiluminescence) over multiple engine cycles. The flame images revealed the tendency of the flame to migrate towards the hotter exhaust side of the combustion chamber, with no complementary bulk air motion apparent in this area in the imaging plane. In terms of fuel effects, the addition of 16% butanol to iso-octane resulted in marginally faster combustion. Fastest combustion was observed with ethanol, in good agreement with laminar burning velocity correlations within the literature. The ethanol could be seen to offset the tendency of migration of the flame toward the exhaust walls under the fixed spark timing conditions. This exhaust migration phenomenon has been noted previously by others in optical pent-roofed engines but without both flow and flame imaging data being available. The results may imply that the spark plug should ideally be biased further towards the intake side of the chamber if the flame is to approach the intake and exhaust walls at similar times resulting in symmetrical flame propagation, reduced premature wall quenching and hence increase combustion stability and thermal efficiency. Such a layout is typically not preferred due to the priority given to the central fuel injector (and associated cooling jacket) location and maximizing the size of the inlet valves for improved volumetric efficiency.

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“…However, the methanol combustion induces corrosion on the components, which are made of copper, brass, or aluminum [19]. Since producing methanol is mostly required either coal-or petroleum-based fuels, ethanol has been widely used in biofuel and blending agents as a commercial fuel [20][21][22][23]. Ethanol can be used in different types of internal combustion engines, even without any modification made for the engine.…”

Section: Introductionmentioning

confidence: 99%

Effects of butanol–gasoline blends on SI engine performance, fuel consumption, and emission characteristics at partial engine speeds

Huynh

Đức

Duong

2019

Int J Energy Environ Eng

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The effects of using butanol-gasoline-blended fuels on performance, fuel consumption, and emission characteristics of a four-cylinder spark-ignition engine were experimentally investigated. The butanol-blending fraction was varied from 10 to 50% by volume. The engine speeds were tested at 2250 and 4250 rpm, while the throttle positions were set at 30% and 70%. The engine performance, specific fuel consumption, and emission properties have been carried out and compared. The results show that, at high throttle position, the flame propagation speed of combustion process as using the butanol-gasoline blends decreases as increasing the butanol-blending fraction and this becomes more obvious with the increase of engine speed. The engine brake torque and power are improved, as the butanol-blending fraction is less than 30% at low open throttle position, while those are gradually decayed as increasing throttle opening level. A significant reduction is observed in specific fuel consumption, as the butanol-blending fraction is less than 30% for all the tests. The emissions of CO, HC, and CO 2 in the case of using butanol-gasoline blends are much better than those in the case of using pure gasoline. However, NOx emission is worse than that of the pure gasoline for all the test blends.

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A comparison of butanol and ethanol flame development in an optical spark ignition engine

Cited by 23 publications

References 23 publications

A study of hydrous ethanol combustion in an optical central direct injection spark ignition engine

A study of hydrous ethanol combustion in an optical central direct injection spark ignition engine

Cyclically resolved flame and flow imaging in an alcohol fuelled SI engine

Effects of butanol–gasoline blends on SI engine performance, fuel consumption, and emission characteristics at partial engine speeds

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