Characterization of Particulate Morphology, Nanostructures, and Sizes in Low-Temperature Combustion with Biofuels

Seong, Heeje; Lee, Kyeong O.; Choi, Soon-Ho; Adams, Cory; Foster, David E.

doi:10.4271/2012-01-0441

Cited by 22 publications

(14 citation statements)

References 26 publications

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“…76 Research has shown that the composition and morphology of soot/particulate matter emissions from LTC strategies can vary widely, [78][79][80][81] and it has also been shown that the two-step soot model requires significant tuning to achieve predictions over a range of combustion modes. 82 Therefore, in this study, the qualitative sooting tendency of a given combustion strategy will be discussed using local equivalence ratio versus local temperature diagrams, like the one shown in Figure 1.…”

Section: Multi-dimensional Cfd Engine Modelingmentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

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Many research studies have shown that low temperature combustion in compression ignition engines has the ability to yield ultra-low NOx and soot emissions while maintaining high thermal efficiency. To achieve low temperature combustion, sufficient mixing time between the fuel and air in a globally dilute environment is required, thereby avoiding fuel-rich regions and reducing peak combustion temperatures, which significantly reduces soot and NOx formation, respectively. It has been demonstrated that achieving low temperature combustion with diesel fuel over a wide range of conditions is difficult because of its properties, namely, low volatility and high chemical reactivity. On the contrary, gasoline has a high volatility and low chemical reactivity, meaning it is easier to achieve the amount of premixing time required prior to autoignition to achieve low temperature combustion. In order to achieve low temperature combustion while meeting other constraints, such as low pressure rise rates and maintaining control over the timing of combustion, in-cylinder fuel stratification has been widely investigated for gasoline low temperature combustion engines. The level of fuel stratification is, in reality, a continuum ranging from fully premixed (i.e. homogeneous charge of fuel and air) to heavily stratified, heterogeneous operation, such as diesel combustion. However, to illustrate the impact of fuel stratification on gasoline compression ignition, the authors have identified three representative operating strategies: partial, moderate, and heavy fuel stratification. Thus, this article provides an overview and perspective of the current research efforts to develop engine operating strategies for achieving gasoline low temperature combustion in a compression ignition engine via fuel stratification. In this study, computational fluid dynamics modeling of the in-cylinder processes during the closed valve portion of the cycle was used to illustrate the opportunities and challenges associated with the various fuel stratification levels.

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Section: Multi-dimensional Cfd Engine Modelingmentioning

confidence: 99%

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

Dempsey

Curran

Wagner

2016

International Journal of Engine Research

136

View full text Add to dashboard Cite

show abstract

“…To determine the particle size and number, the following are used: condensation particle counters (CPC), SMPS, ELPI, EEPS, MOUDI, low-pressure impactors etc. [28,42]. To determine the morphology, soot structure and the elements, the following are used: scanning electron microscopy/energy-dispersive X-ray spectroscopy (REM/EDX), transmission electron microscopy (TEM/ HRTEM), electron energy loss spectroscopy (EELS), electron spin resonance (ESR), atomic emission spectroscopy (AES) [8,42,43] etc.…”

Section: Measuring Techniquesmentioning

confidence: 99%

“…[28,42]. To determine the morphology, soot structure and the elements, the following are used: scanning electron microscopy/energy-dispersive X-ray spectroscopy (REM/EDX), transmission electron microscopy (TEM/ HRTEM), electron energy loss spectroscopy (EELS), electron spin resonance (ESR), atomic emission spectroscopy (AES) [8,42,43] etc. Raman microscopy (RM) and temperature-programmed oxidation (TPO) [30] are used to determine the reactivity of particles.…”

Section: Measuring Techniquesmentioning

confidence: 99%

A literature research about particle emissions from engines with direct gasoline injection and the potential to reduce these emissions

Überall

Otte

Eilts

et al. 2015

Fuel

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“…The combination of a DMS or SMPS (sizer) type measurement with a TEM analysis is rare-with a few examples in the literature [12][13][14]. In most cases a direct comparison between the two measurements is not made.…”

Section: Introductionmentioning

confidence: 99%

“…In most cases a direct comparison between the two measurements is not made. The work of Seong [14] conducted tests using SMPS and TEM analysis and a discrepancy between the two measurements was put down to the volatile organic compounds (VOC) that form the nucleation (very small, below 20nm) mode particles that will be measured by a sizer but not observed in the TEM.…”

Section: Introductionmentioning

confidence: 99%

On Soot Sampling: Considerations when Sampling for TEM Imaging and Differential Mobility Spectrometer

Emberson¹,

Rohani²,

Wang³

et al. 2019

SAE Technical Paper Series

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Particulate matter (PM) has been sampled from a compression ignition engine using a differential mobility spectrometer (Cambustion DMS 500) and for imaging in a transmission electron microscope (TEM) with the aim of coupling these two measuring techniques. A known issue when coupling these two methods is that a devise like the DMS samples all PM, and the TEM only soot. To help resolve this issue, a thermal denuder was designed and built to remove all volatile organic compounds (VOC) from the sample prior to entering the DMS. For TEM imaging, soot was either collected directly onto a TEM grid using the thermophoretic effect or collected onto quartz filters with the soot then transferred onto the TEM grids. The direct to grid technique did not work after the denuder due to the gas temperature being too low for the thermophoretic effect; hence the reason to collect some soot using the quartz filters. Soot was removed from the filters using an ethanol wash/sonication technique. Morphology; diameter of gyration, projected area, primary particle size and fractal dimension have been compared between the two TEM sampling techniques, with or without the denuder. Denuder effectiveness has been assessed using TGA analysis of sampled soot. Issues concerning the sampling process itself are outlined. A comparison between the TEM and the DMS results is conducted with the discrepancies between them discussed. Direct and filter sampling gave similar results as long as the sonication process and grid prep is done properly, otherwise the filter wash technique results in a number of clusters of agglomerates which distorts the post processing and morphological data.

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Characterization of Particulate Morphology, Nanostructures, and Sizes in Low-Temperature Combustion with Biofuels

Cited by 22 publications

References 26 publications

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

A perspective on the range of gasoline compression ignition combustion strategies for high engine efficiency and low NOx and soot emissions: Effects of in-cylinder fuel stratification

A literature research about particle emissions from engines with direct gasoline injection and the potential to reduce these emissions

On Soot Sampling: Considerations when Sampling for TEM Imaging and Differential Mobility Spectrometer

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