Investigation of the Impact of Lean Mixtures on the Performance of GDI Engines

Bontorin, Ana Carolina Bueno; Carvalho, Leonardo de Oliveira

doi:10.4271/2016-36-0326

Cited by 9 publications

(3 citation statements)

References 3 publications

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“…Currently, lean mixture combustion in conventional spark ignition engines reduces pumping losses in the intake manifold by keeping the throttle valve open at low loads. Furthermore, the higher specific heat of the lean mixture increases the efficiency of the Otto cycle, thus increasing the overall efficiency of the engine [2]. The main factor that limits the excess air coefficient is the exhaust gas temperature, which decreases along with the depletion of the mixture.…”

Section: Lean Combustion Of Hydrogenmentioning

confidence: 99%

Possible applications of prechambers in hydrogen internal combustion engines

Matla¹

2022

Combustion Engines

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The use of hydrogen as a fuel for an internal combustion engines has caused many problems for years, the most significant of which seems to be the excessive emission of nitrogen oxides and the tendency to knock combustion. In order to ensure better control of the combustion process in a internal combustion engine powered by hydrogen, it has been proposed to use a split combustion chamber solution. Following paper contains a description of a hydrogen combustion system that includes an analysis of possible technical solutions. The considerations take into account the issues of the dual nature of hydrogen knocking and the problem of burning a stratified charge of a hydrogen-air mixture in a cylinder.

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Section: Lean Combustion Of Hydrogenmentioning

confidence: 99%

Possible applications of prechambers in hydrogen internal combustion engines

Matla¹

2022

Combustion Engines

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“…One way to increase the thermal efficiency of SI is through lean operation. 17 In addition to increasing the ratio of specific heats of the charge and reducing pumping losses, the excess air acts a heat sink, lowering bulk temperatures and reducing heat transfer losses. While the benefits of lean SI are clear, there are two primary drawbacks: lean NO x formation and combustion instability.…”

Section: Introductionmentioning

confidence: 99%

Lean flammability limit of high-dilution spark ignition with ethanol, propanol, and butanol

Gainey

Yan

Moser

et al. 2021

International Journal of Engine Research

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Ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and sec-butanol are six potential carbon-neutral fuels of the future. One application of these carbon-neutral fuels is in high-dilution spark ignition. To understand the potential of these fuels in high-dilution spark ignition, this work experimentally determines the spark ignition lean flammability limit of each fuel with no external, cooled exhaust gas recirculation (EGR), and with 20% external, EGR. The spark ignition lean flammability limit in this work is defined as the excess-air ratio that results in a coefficient of variance of gross indicated mean effective pressure greater than 5%. This is done on an engine with a compression ratio of 12.5, using an intake pressure of 1 bar and an intake temperature of 320 K. It was found that ethanol had the leanest lean limit, due to its high flame speed, followed by n-propanol, isopropanol, and sec-butanol, which all had similar lean limits. n-Butanol and isobutanol had the richest lean limits due their high knock propensity and low flame speed, respectively. The lean limit of each fuel decreased with external, cooled EGR addition, with ethanol as the least sensitive and isopropanol as the most sensitive to EGR addition. Overall, using a high dilution strategy increased the cycle efficiency for each fuel. Ethanol, n-propanol, isopropanol, and sec-butanol all showed promising performance and are great candidates to be combined with an advanced high-dilution SI strategy to enable high-dilution SI with a carbon-neutral fuel.

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“…Lean burn also creates an increase in NO x emissions due to a reduction in three-way catalyst efficiency resulting in a lower combustion stability at high air/fuel ratios . The effect of lean burn on engine efficiency was investigated on a 1.4 L GDI engine using the downsizing and turbocharging technology; the results showed that the lean mixture improved engine fuel consumption . Irimescu et al studied cycle-by-cycle variations under lean operation conditions and reported the effects of operation parameters on the coefficient of variation (COV) and fuel conversion efficiency in lean mixtures.…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Cooled EGR and Air Dilution on Butanol–Gasoline TGDI Engine Operation, Efficiency, Gaseous, and PM Emissions

Zhao

Wang

2020

ACS Omega

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Biobutanol is a promising alternative fuel for sparkignition engines. Exhaust gas recirculation (EGR) and air dilution were evaluated on a TGDI engine fueled with butanol−gasoline (B20) in view of engine operation, efficiency, gaseous emissions, and PM emissions. For the B20 engine, EGR affected combustion more strongly than excess air dilution; the brake thermal efficiency (BTE) under excess air dilution was much higher than that with EGR. The oxygen concentration in the cylinder was also markedly reduced with EGR relative to air dilution, as the partial fresh charge was substituted with nonreactive gas. A reduced oxygen concentration contributed to differences in combustion between excess air dilution and EGR. Higher BTE was observed during combined EGR and excess air dilution operation, though it was slightly lower than that under excess air dilution alone. NO x was also markedly reduced by the combination of EGR and excess air dilution, but was slightly higher than that with EGR alone. Under combined dilution conditions, the particle number (PN) emissions from the B20 engine were reduced significantly, particle sizes decreased, and the nucleate PN significantly decreased.

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Investigation of the Impact of Lean Mixtures on the Performance of GDI Engines

Cited by 9 publications

References 3 publications

Possible applications of prechambers in hydrogen internal combustion engines

Possible applications of prechambers in hydrogen internal combustion engines

Lean flammability limit of high-dilution spark ignition with ethanol, propanol, and butanol

Combined Effects of Cooled EGR and Air Dilution on Butanol–Gasoline TGDI Engine Operation, Efficiency, Gaseous, and PM Emissions

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