An optical investigation of Fischer-Tropsch diesel and Oxymethylene dimethyl ether impact on combustion process for CI engines

Pastor, Javier; García, Antonio; Micó, Carlos; Lewiski, Felipe

doi:10.1016/j.apenergy.2019.114238

Cited by 41 publications

(27 citation statements)

References 43 publications

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“…These have promoted the study of more appropriate alternative fuels. Among them, hydrotreated vegetable oil (HVO), gas-to-liquid (GTL) and new oxygenated fuels like the oxymethylene ethers with the general structure CH 3 -O-(CH 2 -O) n -CH 3, are the most promising alternatives to replace conventional diesel [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

et al. 2020

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The stringent emission regulations have motivated the development of cleaner fuels as diesel surrogates. However, their different physical-chemical properties make the study of their behavior in compression ignition engines essential. In this sense, optical techniques are a very effective tool for determining the spray evolution and combustion characteristics occurring in the combustion chamber. In this work, quantitative parameters describing the evolution of diesel-like sprays such as liquid length, spray penetration, ignition delay, lift-off length and flame penetration as well as the soot formation were tested in a constant high pressure and high temperature installation using schlieren, OH∗ chemiluminescence and diffused back-illumination extinction imaging techniques. Boundary conditions such as rail pressure, chamber density and temperature were defined using guidelines from the Engine Combustion Network (ECN). Two paraffinic fuels (dodecane and a renewable hydrotreated vegetable oil (HVO)) and two oxygenated fuels (methylal identified as OME1 and a blend of oxymethylene ethers, identified as OMEx) were tested and compared to a conventional diesel fuel used as reference. Results showed that paraffinic fuels and OMEx sprays have similar behavior in terms of global combustion metrics. In the case of OME1, a shorter liquid length, but longer ignition delay time and flame lift-off length were observed. However, in terms of soot formation, a big difference between paraffinic and oxygenated fuels could be appreciated. While paraffinic fuels did not show any significant decrease of soot formation when compared to diesel fuel, soot formed by OME1 and OMEx was below the detection threshold in all tested conditions.

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Section: Introductionmentioning

confidence: 99%

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

et al. 2020

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“…In any case, due to the lack of C-C bonds and the high number of oxygen atoms in the molecule, the OMEX combustion process is practically soot free, which makes it an interesting alternative fuel to replace diesel or to be blended with it completely, or partially by blending in OMEX [17]. Some studies on OMEX fuels are available in literature showing good results for soot reduction in either optical vessels [15], optical engines [18], single cylinder diesel engines [17] or multicylinder engines [13]. However, to the authors knowledge, there are no studies analyzing the details of the flame structure of OMEX sprays, and the study of different physicochemical phenomena that occur during the fuel combustion process is a key factor for a better understanding its behavior in the engine.…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Diffusive Flame Structure for Dodecane and OME <sub>X</sub> Fuels for Conditions of Spray A of the ECN

Soriano

Oliver

Micó

et al. 2020

SAE Int. J. Adv. & Curr. Prac. in Mobility

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A comparison of the flame structure for two different fuels, dodecane and oxymethylene dimethyl ether (OMEX), has been performed under condition of Spray A of the Engine Combustion Network (ECN). The experiments were carried out in a constant pressure vessel with wide optical access, at high pressure and temperature and controlled oxygen concentration. The flame structure analysis has been performed by measuring the formaldehyde and OH radical distributions using planar Laser-Induced Fluorescence (PLIF) techniques. To complement the analysis, this information was combined with that obtained with highspeed imaging of OH * chemiluminescence radiation in the UV. Formaldehyde molecules are excited with the 355-nm radiation from the third harmonic of a Nd:YAG laser, whilst OH is excited with a wavelength of 281.00-nm from a dye laser. In both cases, the beam was transformed into a laser sheet in order to excite an axial flame plane and the fluorescence radiation was collected with an intensified camera (ICCD) and proper filtering. Consequently, two-dimensional maps in the axial flame plane were obtained at different instants after the start of injection (ASOI). Signal from both formaldehyde and OH chemical species can be compared, in order to analyze spatial distribution and interaction. When dodecane and OMEX are compared, several differences arise. The second one presents larger lift-off length but remarkably shorter flame length. Additionally, it has been possible to appreciate for this fuel a lower amount of soot formation during combustion.

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“…For the accumulation mode, which are believed to be primarily soot, 9 DFI results in significantly lower numbers compared to CDC due to the enhanced entrainment and/ or mixing upstream of the liftoff length and correspondingly lower local equivalence ratios with DFI. 16,17,20,21 It has been shown previously that ash nanoparticles will often attach to soot agglomerates. 11,35,36 Hence, with fewer soot agglomerates produced by DFI, there are fewer sites on which to attach, and therefore more free nucleation mode particles are observed.…”

Section: Resultsmentioning

confidence: 99%

“…SCREs with optical access to the combustion chamber are even less similar to production multi-cylinder engines, because they must accommodate windows to allow in-situ measurements of temperature, flow, and chemical species composition. [13][14][15][16][17][18] Techniques used to analyze in-cylinder soot particle formation in optical SCREs include laser induced incandescence and elastic scatter image intensity, natural luminosity, diffuse back illumination, and two-color pyrometry. To reduce temperatures and pressures that could be damaging to optical engine hardware, optical SCREs are often operated in ''skip-fired'' mode.…”

Section: Introductionmentioning

confidence: 99%

Solid particulate mass and number from ducted fuel injection in an optically accessible diesel engine in skip-fired operation

Wilmer

Nilsen

Biles

et al. 2021

International Journal of Engine Research

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Ducted fuel injection (DFI) is a novel combustion strategy that has been shown to significantly attenuate soot formation in diesel engines. While previous studies have used optical diagnostics and optical filter smoke number methods to show that DFI reduces in-cylinder soot formation and engine-out soot emissions, respectively, this is the first study to measure solid particle number (PN) emissions in addition to particle mass (PM). Furthermore, this study quantitatively evaluates the use of transient particle instruments for measuring particles from skip-fired operation in an optical single cylinder research engine (SCRE). Engine-out PN was measured using an engine exhaust particle sizer following a catalytic stripper, and PM was measured using a photoacoustic analyzer. The study improves on earlier preliminary emissions studies by clearly showing that DFI reduces overall PM by 76%–79% and PN for particles larger than 23 nm by 77% relative to conventional diesel combustion at a 1200-rpm, 13.3-bar gross indicated mean effective pressure operating condition. The degree of engine-out PM reduction with DFI was similar across both particulate measurement instruments used in the work. Through the use of bimodal distribution fitting, DFI was also shown to reduce the geometric mean diameter of accumulation mode particles by 26%, similar to the effects of increased injection pressure in conventional diesel combustion systems. This work clearly shows the significant solid particulate matter reductions enabled by DFI while also demonstrating that engine-out PN can be accurately measured from an optical SCRE operating in a skip-fired mode. Based on these results, it is believed that DFI has the potential to enable fuel savings when implemented in multi-cylinder engines, both by lowering the required frequency of active diesel particulate filter regeneration, and by reducing the backpressure imposed by exhaust filtration systems.

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An optical investigation of Fischer-Tropsch diesel and Oxymethylene dimethyl ether impact on combustion process for CI engines

Cited by 41 publications

References 43 publications

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

Comparison of the Diffusive Flame Structure for Dodecane and OME <sub>X</sub> Fuels for Conditions of Spray A of the ECN

Solid particulate mass and number from ducted fuel injection in an optically accessible diesel engine in skip-fired operation

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