Experimental Evaluation of Lean-burn and EGR as Load Control Strategies for Methanol Engines

Vancoillie, Jeroen; Sileghem, Louis; Ginste, Maarten Van de; Demuynck, Joachim; Galle, Jonas; Verhelst, Sebastian

doi:10.4271/2012-01-1283

Cited by 22 publications

(9 citation statements)

References 9 publications

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“…These were compared against the conventional throttled stoichiometric operation on the single-cylinder engine. 58 These strategies, respectively, used variable mixture strength or stoichiometric mixtures and variable amounts of external EGR to control load while the throttle position was fixed (and preferably wide open to the benefit of minimum pumping work).…”

Section: Experiments Into Efficiency Improvements and Engine Load Conmentioning

confidence: 99%

See 1 more Smart Citation

Alcohol fuels for spark-ignition engines: Performance, efficiency and emission effects at mid to high blend rates for binary mixtures and pure components

Turner

Lewis

Akehurst

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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The paper evaluates the results of tests performed using mid-and high-level blends of the low-carbon alcohols, methanol and ethanol, in admixture with gasoline, conducted in a variety of test engines to investigate octane response, efficiency and exhaust emissions, including those for particulate matter. In addition, pure alcohols are tested in two of the engines, to show the maximum response that can be expected in terms of knock limit and efficiency as a result of the beneficial properties of the two alcohols investigated. All of the test work has been conducted with blending of the alcohols and gasoline taking place outside the combustion system, that is, the two components are mixed homogeneously before introduction to the fuel system, and so the results represent what would happen if the alcohols were introduced into the fuel pool through a conventional single-fuel-pump (dispenser) approach. While much has been written on the effect of blending the light alcohols with gasoline in this way, the results present significant new findings with regard to the effect of the enthalpy of vaporization of the alcohols in terms of particulate exhaust emissions. Also, in one of the tests, two mid-level blends are tested in a highly downsized prototype engine -these blends being matched for stoichiometry, enthalpy of vaporization and volumetric energy content. The consequences of this are discussed and the results show that this approach to blend formulation creates fuels which behave in the same manner in a given combustion system; the reasons for this are discussed. One set of tests using pure methanol alternately with cooled exhaust gas recirculation and with excess air shows a significant increase in thermal efficiency that can be expected as the blend level is increased. The effect on nitrous oxide emissions is shown to be similarly beneficial, this being primarily a result of the enthalpy of vaporization of the alcohol cooling the charge coupled with the lower adiabatic flame temperature of the alcohol. Whereas it is normally a beneficial characteristic in spark-ignition combustion systems, one disadvantage of a high value of enthalpy of vaporization is shown in another series of tests in that, in admixture with gasoline, it is a driver on flash boiling of the hydrocarbon component in the blend in direct injection combustion systems. In turn, this causes the particulate emissions of the engine to increase quite markedly over those of ethanol-gasoline blends at the same stoichiometry. The paper shows for the first time the dichotomy of the potential efficiency improvement with the challenge of particulate control. This effect poses a challenge for the future introduction and use of such high blend rate fuels in engines without particulate filters. Although it must be stated that the overall particulate emissions of the methanolgasoline blend are lower than for gasoline, the effect is only present at extremely low load, and that there is a likelihood that particulate filters will be adopted in production vehicle anyway...

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Section: Experiments Into Efficiency Improvements and Engine Load Conmentioning

confidence: 99%

“…For the lean-burn strategy, the combustion stability limits were λ = 1.5 and λ = 1.25 on methanol and gasoline, respectively. 58…”

Section: Experiments Into Efficiency Improvements and Engine Load Conmentioning

confidence: 99%

Alcohol fuels for spark-ignition engines: Performance, efficiency and emission effects at mid to high blend rates for binary mixtures and pure components

Turner

Lewis

Akehurst

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…Methanol is the simplest liquid synthetic fuel and no novelty for use in internal combustion engines. Substantial efficiency improvements and emissions reductions of unburned hydrocarbons and oxides of nitrogen compared to conventional gasoline were reported in numerous studies, [4][5][6][7][8][9][10][11][12][13] even with fuel blends containing small fractions of methanol.…”

Section: Introductionmentioning

confidence: 99%

Effects of stroke on spark-ignition combustion with gasoline and methanol

Wouters

Burkardt

Fischer

et al. 2021

International Journal of Engine Research

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Besides electrification of the powertrain, new synthetic alternative fuels with the potential to be produced from renewable sources come into focus. Methanol is the most elementary liquid synthetic fuel and no novelty for use in internal combustion engines. This article presents pathways to achieve high efficiency spark-ignition methanol combustion on a direct injection spark-ignition single-cylinder research engine with two different stroke-to-bore ratios (1.2 and 1.5) and a constant bore. In addition, two compression ratios (CRs) were investigated on each setup: CR = 10.8 using RON95 E10 gasoline fuel and a higher CR = 15 using neat methanol. In contrast to previous studies of stroke-to-bore ratio influences on SI combustion, this article aims at demonstrating how the advantages of a high stroke-to-bore ratio can be exploited by combining a long-stroke engine with increased compression ratios and methanol. The increased stroke enhances the tumble motion due to a higher piston speed and a larger compression volume which improves the mixture homogenization and combustion velocity. Moreover, the lower surface/volume ratio results in a reduced heat transfer. When using RON95E10 gasoline fuel and CR = 10.8, an efficiency gain of up to 1.6% could be achieved with the long-stroke compared to the short-stroke especially at lower engine loads. With methanol and CR = 15, an efficiency gain of up to 1.6% could be achieved with the long-stroke setup compared to the short-stroke engine. Subsequently, lean burn conditions were experimentally investigated with methanol and CR = 15. The longer stroke allowed the lean burn limit to be extended from λ = 1.9 to λ = 2.0 with an efficiency gain of up to 2.2%. A maximum indicated efficiency of 47.4% could be achieved at λ = 1.9 with methanol on the long-stroke engine with CR = 15.

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“…All the investigations reported an increased engine efficiency and reduced exhaust gas emissions of unburned HC and oxides of nitrogen compared to gasoline. 6,10–18 However, the extent to which the efficiency and emissions can be improved compared to gasoline operation depends on whether methanol is tested in a flex-fuel or dedicated engine. Furthermore, most of these studies performed investigations with relatively low compression ratios.…”

Section: Introductionmentioning

confidence: 99%

Limits of compression ratio in spark-ignition combustion with methanol

Wouters

Burkardt

Pischinger

2021

International Journal of Engine Research

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A shift toward a circular and [Formula: see text]-neutral world is required, in which rapid defossilization and lower emissions are realized. A promising alternative fuel that has gained traction is methanol, thanks to its favorable and clean-burning fuel properties as well as its ability to be produced in a carbon-neutral process. Especially methanol’s high knock resistance and its combustion stability offer the opportunity to operate an engine at both a high compression ratio and a high excess air dilution. Although methanol has been investigated in series-production engines for passenger car applications, there is a lack of investigations on a dedicated engine that can operate at methanol’s knock limit. In this paper, methanol’s knock limitation is experimentally assessed by applying high compression ratios to a direct injection spark-ignition single-cylinder research engine. To that end, four compression ratios were investigated: 10.8, 15.0, 17.7, and 20.6. With compression ratios of 15.0 and 17.7, the lean-limit was increased to excess air ratios of 2.0 and 2.1, respectively, compared to 1.7 at a compression ratio of 10.8. For the highest compression ratio of 20.6, the maximum lean burn limit was increased to an excess air ratio of 1.9 due to achieving the maximum cylinder pressure limit. Despite the minor increase in lean-limit, a maximum indicated efficiency of 48.7% was achieved with the highest compression ratio of 20.6. However, even at this high compression ratio, methanol did not show a knock limitation. The investigations in this work provide profound knowledge for future engine investigations with methanol.

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Experimental Evaluation of Lean-burn and EGR as Load Control Strategies for Methanol Engines

Cited by 22 publications

References 9 publications

Alcohol fuels for spark-ignition engines: Performance, efficiency and emission effects at mid to high blend rates for binary mixtures and pure components

Alcohol fuels for spark-ignition engines: Performance, efficiency and emission effects at mid to high blend rates for binary mixtures and pure components

Effects of stroke on spark-ignition combustion with gasoline and methanol

Limits of compression ratio in spark-ignition combustion with methanol

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