In-Cylinder Measurements of Particulate Formation in an Indirect Injection Diesel Engine

Pipho, M. J.; Ambs, Jeffrey L.; Kittelson, David B.

doi:10.4271/860024

Cited by 18 publications

(4 citation statements)

References 3 publications

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“…20 Recently, TEM grids were mounted inside a cylinder allowing detailed studies of particle nanostructure using high resolution transmission electron microscopy 21 (HR-TEM). A total cylinder sampling system 22 can be used for rapid (1 ms) extraction of the full cylinder volume from a single combustion cycle and to study soot properties using an array of off-line techniques including HR-TEM and Raman microscopy. 23,24 Off-line techniques involve particle sampling, handling and often chemical processing that could lead to unintended changes in particle properties.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Recently, TEM grids were mounted inside a cylinder allowing detailed studies of particle nanostructure using high resolution transmission electron microscopy (HR-TEM). A total cylinder sampling system can be used for rapid (1 ms) extraction of the full cylinder volume from a single combustion cycle and to study soot properties using an array of off-line techniques including HR-TEM and Raman microscopy. , Off-line techniques involve particle sampling, handling and often chemical processing that could lead to unintended changes in particle properties. Online aerosol measurement techniques are commonly used in ambient measurements to characterize particle properties directly in the aerosol phase, for example to investigate the transformation of climate-relevant soot properties upon aging in the atmosphere .…”

Section: Introductionmentioning

confidence: 99%

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Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry

Malmborg

Eriksson

Shen

et al. 2017

Environ. Sci. Technol.

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To design diesel engines with low environmental impact, it is important to link health and climate-relevant soot (black carbon) emission characteristics to specific combustion conditions. The in-cylinder evolution of soot properties over the combustion cycle and as a function of exhaust gas recirculation (EGR) was investigated in a modern heavy-duty diesel engine. A novel combination of a fast gas-sampling valve and a soot particle aerosol mass spectrometer (SP-AMS) enabled online measurements of the in-cylinder soot chemistry. The results show that EGR reduced the soot formation rate. However, the late cycle soot oxidation rate (soot removal) was reduced even more, and the net effect was increased soot emissions. EGR resulted in an accumulation of polycyclic aromatic hydrocarbons (PAHs) during combustion, and led to increased PAH emissions. We show that mass spectral and optical signatures of the in-cylinder soot and associated low volatility organics change dramatically from the soot formation dominated phase to the soot oxidation dominated phase. These signatures include a class of fullerene carbon clusters that we hypothesize represent less graphitized, C-containing fullerenic (high tortuosity or curved) soot nanostructures arising from decreased combustion temperatures and increased premixing of air and fuel with EGR. Altered soot properties are of key importance when designing emission control strategies such as diesel particulate filters and when introducing novel biofuels.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry

Malmborg

Eriksson

Shen

et al. 2017

Environ. Sci. Technol.

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show abstract

“…However, there is not always a clear relationship between engine load and the composition of some exhaust components such as PAHs. For example, an increase in engine load decreased the amount of PAHs absorbed to diesel exhaust PM in one study (Jensen & Hites, 1983), but increased total PAHs emissions in a second report (Pipho et al, 1986). Even a slight increase in the oxygen content of DEP (induced via reactions with ozone) can increase the potency of DEP to induce rat lung inflammation and damage (Madden et al, 2000).…”

mentioning

confidence: 97%

Nasal Responses in Asthmatic and Nonasthmatic Subjects Following Exposure to Diesel Exhaust Particles

Kongerud

Madden

Hazucha

et al. 2006

Inhalation Toxicology

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Asthma rates have been increasing worldwide, and exposure to diesel exhaust particles (DEP) may be implicated in this increase. DEP may also play a role in the increased morbidity and mortality associated with ambient airborne particulate matter (PM) exposure. Two types of nasal responses have been reported for human subjects nasally instilled with one type of DEP: alterations in cytokines responses, and an increase in immunoglobulin E (IgE) production. Since DEP composition can vary depending on several factors, including fuel composition and engine load, the ability of another DEP particle and ozone-treated DEP to alter nasal IgE and cytokine production was examined. Nonasthmatic and asthmatic subjects were intranasally instilled with 300 microg NIST 1650 DEP per nostril, NIST 1650 DEP previously exposed to ozone (ozDEP; 300 microg/nostril), or vehicle. Subjects underwent nasal lavage before DEP exposure, and 4 and 96 h after exposure. Nasal cell populations and soluble mediators in the nasal lavage fluid were characterized. Total cell number, cell types, cell viability, concentrations of soluble mediators (including interleukin [IL]-8, IL-6, IgE, and granulocyte-macrophage colony-stimulating factor [GM-CSF]) were not altered by either DEP or ozDEP exposure. NO levels were not altered by either particle exposure. These findings suggest that DEP can be relatively noninflammatory and nontoxic, and that the physicochemical characteristics of DEP need to be considered when assessing the health effects of exposure to diesel exhaust.

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“…The amount of material deposited by thermophoresis can be significant if appreciable cooling of the gas by surfaces occurs. Pipho et al (4) observed that during sampling of the entire cylinder contents of a diesel engine, a portion of the soot collected comes from re-entrained material which was formed and deposited on the cylinder walls during the combustion process. The explanation for this re-entrainment is that the high-velocity flow toward the sampling port leads to a shear field which removes significant quantities of soot from the combustion chamber walls.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study of particulate re-entrainment from the combustion chamber walls of a diesel engine

Abu-Qudais

Kittelson

1997

Proceedings of the Institution of Mechanical Engineers, Part D:

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The purpose of this research was to investigate the influence of the in-cylinder surfaces on the net emission of the particulate matter in the exhaust of a single cylinder, diesel engine. In order to obtain this information, time-resolved sampling was done to characterize the particulate matter emitted in the engine exhaust. A rotating probe sampled the free exhaust plume once each engine cycle. The rotation of the probe was synchronized with the engine cycle in such a way that the samples could be taken at any predetermined crank angle degree window. The sampling probe was designed for isokinetic sampling in order to obtain reliable results. To characterize the exhaust particulate in real time, a filter for mass concentration measurements was used. The results showed about 45 per cent higher mass concentrations as well as particles of larger diameter emitted during blowdown than late in the displacement phase of the exhaust stroke. This suggests that high in-cylinder shear rates and velocities which are associated with the blowdown process, cause the deposited soot to be re-entrained from the surfaces of the combustion chamber, where re-entrainment is favoured by conditions of high surface shear.A mathematical model to predict the amount of soot re-entrained from the cylinder walls is presented. This model is based on information presented in the literature along with the results of the time-resolved measurements of mass concentration. This model supported the hypothesis of soot deposition during the combustion process, with subsequent re-entrainment during the blowdown process of the exhaust stroke.

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In-Cylinder Measurements of Particulate Formation in an Indirect Injection Diesel Engine

Cited by 18 publications

References 3 publications

Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry

Evolution of In-Cylinder Diesel Engine Soot and Emission Characteristics Investigated with Online Aerosol Mass Spectrometry

Nasal Responses in Asthmatic and Nonasthmatic Subjects Following Exposure to Diesel Exhaust Particles

Experimental and theoretical study of particulate re-entrainment from the combustion chamber walls of a diesel engine

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