Effect of Syngas (H<sub>2</sub>/CO) on SI Engine Knock under Boosted EGR and Lean Conditions

Han, Taehoon; Lavoie, George A.; Wooldridge, Margaret S.; Boehman, André L.

doi:10.4271/2017-01-0670

Cited by 17 publications

(7 citation statements)

References 29 publications

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“…The burned temperature values of methanol and SG50 are similar, so the CO emission is almost the same between the two fuels. Second, the ratio of hydrogen to methanol (or H/C ratio) increases when syngas is added, leading to the decrease of carbon-related emissions such as CO. 70 This is similar to the observation in the research of Han et al, 71 where the CO concentration in exhaust gases was higher with EGR dilution, compared to air dilution (at the same ϕ′ = 0.8), and there was no clear change in CO emission with varied syngas fraction.…”

Section: Energy and Fuelssupporting

confidence: 89%

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Nguyen

Verhelst

2017

Energy Fuels

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The current work investigates the flame structure and the propagation of premixed laminar flame fronts for mixtures of diluted methanol−air enriched by fuel reforming products under spark ignition engine conditions. Two engine concepts were investigated: one with external fuel reforming (EFR) and one with reformed exhaust gas recirculation (R-EGR).Here, the fuel reformate (or syngas) is a mixture of H 2 , CO, and CO 2 with a CO selectivity of 6.5%, which is used to represent the products of methanol steam reforming over a Cu−Mn/Al foam catalyst. The simulations were exercised over a wide range of dilution level and unburned gas temperature at 40 bar with a skeletal chemical kinetic mechanism using zero/one-dimensional codes. Two types of dilutionair and EGRwere compared at the same fuel-to-charge equivalence ratio (ϕ′). The results showed that the knock limit for spark-ignited operation is extended with rising dilution levels, especially when diluted by an R-EGR mixture. Syngas addition also leads to a reduced knock tendency. At the knock limit, the fraction of heat released by autoignition is greater at a higher dilution rate. At the lower flammability limit, the stable flame propagation range is expanded to a lower unburned gas temperature when using air dilution. Under stoichiometric conditions, dilution with an R-EGR mixture is recommended for partial load operation, because it provides a stable flame at high dilution levels. The influence of gas properties were also investigated, where a shorter ignition delay after compression was observed with a leaner mixture. The ignition delay increased with a higher EGR ratio, especially in the case of the R-EGR mixture. Therefore, the knock tendency increases with a leaner mixture. However, the knock ringing intensity decreases if the mixture is diluted by air. A mixture diluted by R-EGR can reduce the knock tendency, compared to the two EGR dilution cases, and can decrease the knock ringing intensity, compared to the two air dilution cases at high dilution ratios.

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Section: Energy and Fuelssupporting

confidence: 89%

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Nguyen

Verhelst

2017

Energy Fuels

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“…Reducing the peak temperature of the combustion gas allows the emission of NOx to decrease. The fuel burning rates are lower with syngas fuel operation due to the presence of more diluted gases such as CO, CO 2 , and N 2 and outcomes that minimize the increase in‐cylinder gas temperature 52,53 . The combustion process occurs without much intensity for syngas operation due to its poor calorific value, lower flame propagation, 54 and longer combustion time may be the explanations for the peak reduction mean gas temperature.…”

Section: Resultsmentioning

confidence: 99%

Experimental based comparative exergy analysis of a spark‐ignition Honda GX270 Genset engine fueled with LPG and syngas

Ganesan

Sahoo

Porpatham

et al. 2022

Energy Science & Engineering

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The present study investigates three different fuels such as gasoline, liquefied petroleum gas (LPG), and syngas in spark-ignition Honda GX270 Genset engine under wide-open throttle position on its performance, combustion characteristic as well as availability analysis. The results showed that when the engine operated with gasoline fuel, the brake thermal efficiency was higher than that of LPG and syngas by 6.2% and 7.4%, respectively, throughout the engine load condition. Brake-specific fuel consumption of the engine with syngas (660 g/kW h) and LPG fuel (812 g/kW h) was higher than that of the gasoline fuel (510 g/kW h) at the 4.5 kW of engine load. The engine emission results showed syngas operation caused a significant reduction in NOx by 58.4%, CO by 16.5%, HC by 23.2% compared to gasoline fuel at peak load conditions. On the other hand, exergy analysis concludes the exergy efficiency for all the test fuels increases with an increase in engine load due to a high rise in shaft output. At a 4.5 kW power output, the exergy efficiency of the engine was improved to 46.45% from 45.62% and 29.73% with syngas, gasoline, and

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“…The peak-to-peak amplitude of the oscillations is a convenient way of defining the knock intensity (KI). An example illustrating KI ;3.5 bar is shown in Figure 6, from data provided by Han et al 6 Figure 6 also shows a sudden increase in pressure rise rate which occurs earlier than the pressure oscillations. This change in rise rate has been referred to as the ''knock point'' by Swarts et al 19,20 and Foong et al 21 in CFR engine studies under low speed RON conditions.…”

Section: Knock Intensity Modelsmentioning

confidence: 95%

“…An experimental KI dataset recently became available from a Ricardo single cylinder engine as part of a DOE sponsored project at UM by Han et al 6 Figure 7 plots experimental KI values versus CA50 from 200 individual cycles from each of four spark timings with average CA50 ranging from 18 to 23°ATDC. Engine speed was 1500 rpm; equivalence ratio F = 0.8, intake/exhaust pressures were 1.2/1.4 bar and gasoline fuel with AKI = 87 was used.…”

Section: Knock Intensity Versus Ca50 (Ricardo Engine)mentioning

confidence: 99%

Knock and knock intensity models for boosted SI conditions with gasoline-ethanol blends

Lavoie

Middleton

Martz

et al. 2021

International Journal of Engine Research

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In this work, a previously developed, two-stage table-lookup kinetic method for surrogate Toluene Reference Fuels (TRF) was extended to gasoline-ethanol blends and exercised in a GT-POWER model of knock in several engines. Experimentally, the knock limit is normally determined by the magnitude of pressure oscillations, known as the knock intensity (KI), rather than the crank angle of initial pressure oscillations or the crank angle of auto-ignition, which is difficult to identify. A number of empirical expressions of knock intensity have been developed for modeling purposes which relate the knock intensity to the crank angle and conditions at auto-ignition, and are available in the literature. These models were implemented into a GT-POWER model and tested against experimental knock-limited data for gasoline and gasoline-ethanol blends. The KI models are phenomenological in nature and are based on varying conceptual views of the knock event. With calibration all methods gave satisfactory results at mid-speed conditions when compared with the experimental data. Some deviations were seen at low and high speeds. Low speeds are potentially important because both RON and MON testing occurs under such conditions. Implications of the results and their relationship to recent knock experimental work are discussed and suggestions offered for improved knock models.

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Effect of Syngas (H₂/CO) on SI Engine Knock under Boosted EGR and Lean Conditions

Cited by 17 publications

References 29 publications

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Experimental based comparative exergy analysis of a spark‐ignition Honda GX270 Genset engine fueled with LPG and syngas

Knock and knock intensity models for boosted SI conditions with gasoline-ethanol blends

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Effect of Syngas (H2/CO) on SI Engine Knock under Boosted EGR and Lean Conditions

Cited by 17 publications

References 29 publications

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Computational Study of the Laminar Reaction Front Properties of Diluted Methanol–Air Flames Enriched by the Fuel Reforming Product

Experimental based comparative exergy analysis of a spark‐ignition Honda GX270 Genset engine fueled with LPG and syngas

Knock and knock intensity models for boosted SI conditions with gasoline-ethanol blends

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About

Effect of Syngas (H₂/CO) on SI Engine Knock under Boosted EGR and Lean Conditions