Physical and chemical characterization of SIDI engine particulates

Gaddam, Chethan K.; Wal, Randy L. Vander

doi:10.1016/j.combustflame.2013.05.025

Cited by 131 publications

(85 citation statements)

References 43 publications

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“…Previous work has suggested that oxygenated species can be attached to surfaces of soot particles of varying maturity emitted from flames and diesel engines, even before atmospheric processing (24)(25)(26)(27)(28)(29)(30)(31)(32). Functional groups that have been identified include alcohols/enols, carbonyls, peroxies, and ethers.…”

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confidence: 99%

Formation and emission of large furans and oxygenated hydrocarbons from flames

Johansson

Dillstrom

Monti

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Many oxygenated hydrocarbon species formed during combustion, such as furans, are highly toxic and detrimental to human health and the environment. These species may also increase the hygroscopicity of soot and strongly influence the effects of soot on regional and global climate. However, large furans and associated oxygenated species have not previously been observed in flames, and their formation mechanism and interplay with polycyclic aromatic hydrocarbons (PAHs) are poorly understood. We report on a synergistic computational and experimental effort that elucidates the formation of oxygen-embedded compounds, such as furans and other oxygenated hydrocarbons, during the combustion of hydrocarbon fuels. We used ab initio and probabilistic computational techniques to identify low-barrier reaction mechanisms for the formation of large furans and other oxygenated hydrocarbons. We used vacuum-UV photoionization aerosol mass spectrometry and X-ray photoelectron spectroscopy to confirm these predictions. We show that furans are produced in the high-temperature regions of hydrocarbon flames, where they remarkably survive and become the main functional group of oxygenates that incorporate into incipient soot. In controlled flame studies, we discovered ∼100 oxygenated species previously unaccounted for. We found that large alcohols and enols act as precursors to furans, leading to incorporation of oxygen into the carbon skeletons of PAHs. Our results depart dramatically from the crude chemistry of carbonand oxygen-containing molecules previously considered in hydrocarbon formation and oxidation models and spearhead the emerging understanding of the oxidation chemistry that is critical, for example, to control emissions of toxic and carcinogenic combustion by-products, which also greatly affect global warming.furans | oxygenated hydrocarbons | soot | organic carbon | black carbon

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confidence: 99%

Formation and emission of large furans and oxygenated hydrocarbons from flames

Johansson

Dillstrom

Monti

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…PM pollutants are currently of considerable interest because medical findings have indicated that exposure to ultrafine aerosol particles (<100 nm diameter) from internal combustion engines cause significant health risks [7,8,[21][22][23][24]. Furthermore, previous studies have indicated that GDI engines produce considerably hazardous nucleation mode particles, which are typically a complex mixture of solid and more volatile particles [8,17,18,[25][26][27][28]. Based on the high market growth of GDI vehicles, the European Union (EU) has regulated the particle number (PN) standard for GDI vehicles, which considers non-volatile particles with a diameter above 23 nm, in the Euro-6 vehicle emissions standards [18,20,21,24].…”

Section: Introductionmentioning

confidence: 99%

“…Engine-out particles consist of combustion-generated solid carbon particles and some organic compounds [7][8][9]18,21]. The solid particles become coated with condensed and adsorbed organic compounds, including unburned hydrocarbons and oxygenated hydrocarbons [8,[25][26][27]29,30]. Particle size distributions are generally classified into three modes: nucleation mode (5 nm < dp < 30 nm), accumulation mode (30 nm < dp < 1000 nm) and coarse mode (1000 nm < dp).…”

Section: Introductionmentioning

confidence: 99%

“…Particle size distributions are generally classified into three modes: nucleation mode (5 nm < dp < 30 nm), accumulation mode (30 nm < dp < 1000 nm) and coarse mode (1000 nm < dp). Exhaust particles containing volatile organic compounds that are less than 23 nm in size formed during combustion in locally rich regions are substantially oxidized in the TWC, while almost all of the accumulation mode particles are passed through the catalyst without purification [25,27,[33][34][35]. Therefore, a cost-effective gasoline particulate filter (GPF) can be adopted for GDI vehicles to reduce the nano-PM emissions to satisfy future PN emission regulations [10,27,[29][30][31][36][37][38][39].…”

Section: Introductionmentioning

confidence: 99%

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Nanoparticle Filtration Characteristics of Advanced Metal Foam Media for a Spark Ignition Direct Injection Engine in Steady Engine Operating Conditions and Vehicle Test Modes

et al. 2015

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Abstract:In this study, the particle formation and reduction characteristics at the engine-out position, after a three-way catalyst (TWC) and a metal foam gasoline particulate filter (GPF), were evaluated for a gasoline direct-injection (GDI) engine under part-load operating conditions. The vehicle tests were performed under the Federal Test Procedure-75 (FTP-75) and the Highway Fuel Economy Test (HWFET) modes. Particle number (PN) concentrations, size distributions, and the filtering efficiency with the GPF were evaluated with a condensation particle counter (CPC) and a differential mobility spectrometer (DMS500). Under steady engine operating conditions, the PN concentrations at the engine-out position were 9.7 × 10 5 -2.5 × 10 6 N/cc. While, the PN concentrations after the GPF were 9.2 × 10 4 -3.5 × 10 5 N/cc, and the PN was reduced by 77%-96%. The PN filtering efficiency with the GPF-GDI vehicle reached approximately 58% in the FTP-75 and 62% in the HWFET mode. The PN concentration of the GPF-GDI vehicle was significantly reduced to 3.95 × 10 11 N/km for the FTP-75 and 8.86 × 10 10 N/km for the HWFET mode.The amount of nucleation mode particles below 23 nm was substantially reduced with the GPF-GDI vehicle. The fuel economy, CO2, and regulated emissions of the GPF-GDI vehicle were equivalent to those of the base GDI vehicle under the vehicle certification modes. OPEN ACCESSEnergies 2015, 8 1866

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“…Transmission Electron Microscopy (TEM) is an ex situ method for direct characterization of soot morphology (Medalia and Heckman 1969;Samson et al 1987;Brasil et al 1999;Gaddam and Vander Wal 2013;Kholghy et al 2013;Dastanpour and Rogak 2014;Johnson et al 2015;Thajudeen et al 2015). Statistically reliable primary particle sizes can only be acquired by time-consuming analysis of a great number of TEM images.…”

Section: Introductionmentioning

confidence: 99%

Improved sizing of soot primary particles using mass-mobility measurements

Dastanpour

Rogak

Graves

et al. 2015

Aerosol Science and Technology

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The properties and impacts of aggregated aerosol particles (i.e., soot, metal oxide fumes) depend on their morphology, as characterized by fractal dimension, prefactor, and primary particle diameter. The morphology may be measured directly by time-consuming ex situ microscopy or rapid but indirect in situ methods. Previously, it was found that particle mass and mobility measurements could be used for the estimation of the primary particle diameter of zirconia aggregates, using plausible assumptions related to the fractal structure (specifically, prefactor k a and exponent D a ). Since the formation and growth of zirconia aggregates are different from carbon soot, here we compare primary particle diameters measured directly from transmission electron microscopy analysis of soot particles with the diameters estimated from mass-mobility measurements. Performing extensive measurements on soot emissions from two reciprocating engines over a range of operating conditions, we found that there are no universal values of k a and D a that can be used for all conditions. However, new optimized values of k a and D a are estimated here for soot particles. The variation of the primary particle diameter with particle size is also taken into consideration and is shown to be essential to obtain physically realistic results. Using optimized values of k a and D a , the average primary particle sizing error is reduced for all soot types. This suggests that with some calibration, in situ sizing of the primary particle diameter, using mass and mobility measurements, can provide useful accuracy.

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Physical and chemical characterization of SIDI engine particulates

Cited by 131 publications

References 43 publications

Formation and emission of large furans and oxygenated hydrocarbons from flames

Formation and emission of large furans and oxygenated hydrocarbons from flames

Nanoparticle Filtration Characteristics of Advanced Metal Foam Media for a Spark Ignition Direct Injection Engine in Steady Engine Operating Conditions and Vehicle Test Modes

Improved sizing of soot primary particles using mass-mobility measurements

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