Diesel Exhaust Particle Size: Measurement Issues and Trends

Abdul-Khalek, Imad S.; Kittelson, David B.; Graskow, B. R.; Wei, Qiang; Bear, F.

doi:10.4271/980525

Cited by 221 publications

(162 citation statements)

References 16 publications

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“…Table 5 summarizes exhaust measurements of particle size and number concentration data from selected studies of diesel and gasoline engines. 27,[260][261][262][263][264][265][266] The exhaust tailpipe data show that IC engines are a source of particles smaller than 100 nm at initial concentrations greater than 10 6 /cm 3 , which is consistent with measurements of ambient particle size distributions at various distances from urban highways. 267,268 The sizes of diesel particulate emission can be approximated by a bimodal lognormal distribution.…”

Section: Internal Combustion Enginessupporting

confidence: 68%

“…Typical exhaust PM mass concentrations from well-maintained modern diesel engines are 15-30 mg/m 3 . 262 With older engines, the PM mass is higher, the number of ultrafines is much lower, and a condensation or accumulation mode dominates the number distribution. 269 The high particle number of 1 × 10 9 /cm 3 reported for a 1991 Cummins engine by Bagley et al 260 has led to the speculation that the reduced particle mass emissions in the newer diesels has resulted in increased particle number.…”

Section: Internal Combustion Enginesmentioning

confidence: 99%

“…267,268 The sizes of diesel particulate emission can be approximated by a bimodal lognormal distribution. 262 The nanoparticles in the ultrafine transient mode of diesel engines represent only 0.1-1.5% of particle volume (mass) but 35-97% of the particle number. 262 Most of the PM mass is in a mode with a diameter between 0.01 and 0.1 µm.…”

Section: Internal Combustion Enginesmentioning

confidence: 99%

“…262 The nanoparticles in the ultrafine transient mode of diesel engines represent only 0.1-1.5% of particle volume (mass) but 35-97% of the particle number. 262 Most of the PM mass is in a mode with a diameter between 0.01 and 0.1 µm. From the available studies, the relative importance of surface growth and coalescence in determining the particle size in this larger mode is unclear.…”

Section: Internal Combustion Enginesmentioning

confidence: 99%

See 3 more Smart Citations

Combustion Aerosols: Factors Governing Their Size and Composition and Implications to Human Health

Lighty

Veranth

Sarofim

2000

Journal of the Air & Waste Management Association

1,021

600

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Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 µm (PM 2.5 ) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-temperature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated that susceptible individuals are being harmed by ambient PM. Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution. Time-and size-resolved PM measurements are needed for testing mechanistic toxicological hypotheses, for characterizing the relationship between combustion operating conditions and transient emissions, and for source apportionment studies to develop air quality plans. Citations are provided to more specialized reviews, and the concluding comments make suggestions for further research.

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Section: Internal Combustion Enginessupporting

confidence: 68%

Section: Internal Combustion Enginesmentioning

confidence: 99%

Section: Internal Combustion Enginesmentioning

confidence: 99%

Section: Internal Combustion Enginesmentioning

confidence: 99%

See 2 more Smart Citations

Combustion Aerosols: Factors Governing Their Size and Composition and Implications to Human Health

Lighty

Veranth

Sarofim

2000

Journal of the Air & Waste Management Association

1,021

600

View full text Add to dashboard Cite

show abstract

“…Diesel aggregates were generated using a John Deere 4045H 4 cylinder 4.5L Diesel engine operated at a medium load (1400 rpm, 250 N-m). The aerosol sample was extracted from the exhaust pipe and diluted using a two-stage ejector dilutor system (shown in Figure 1, part b1), which is described in detail elsewhere (Abdul-Khalek et al 1998). A short transfer line was used to bring a fraction of the exhaust to the first stage of dilution.…”

Section: Aggregate Particle Generationmentioning

confidence: 99%

Bipolar Diffusion Charging of Aggregates

Xiao

Swanson

Pui

et al. 2012

Aerosol Science and Technology

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In this paper, the effect of particle morphology on bipolar diffusion charging is studied. A modified tandem differential mobility analyzer (TDMA) method used to measure the charge distribution of submicron particles in the range of 70-300 nm is described in detail. The method requires an independent measurement of the neutral fraction, followed by the measurement of the size-dependent charge distribution, which requires the knowledge of the neutral fraction. The method was validated experimentally using dioctyl sebacate and ammonium sulfate spherical particles and compared with Fuchs' theory. Diesel particles and silver aggregates were used to evaluate the impact of morphology on charging. The results show that aggregates have a slightly lower (about 7%) neutral fraction than spheres. These results are in agreement with the predictions of Lall and Friedlander's theory and previous studies. However, results from charge distribution indicate that more (about 46%) particles are negatively charged than predicted by Lall and Friedlander's theory, while 32% fewer particles are positively charged. This relatively large asymmetry between the negative and the positive charge fraction is not fully predicted by either Fuchs' or aggregate charging theories. Our results suggest that the current inversion method of scanning mobility particle sizer (SMPS) data, based on Fuchs' or Lall and Friedlander's distribution, would underestimate the total number concentration by about 15% or 27% if applied to diesel aggregates.

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Particle Formation and Models

Kittelson

Kraft

2014

Encyclopedia of Automotive Engineering

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This chapter reviews work on aerosols originating from internal combustion engines with an emphasis on soot formation during combustion as well as formation of semi‐volatile and ash particles during combustion and subsequent cooling and dilution processes. Mathematical models of particle formation in engines and remaining modeling challenges are also discussed. Aerosols are formed during combustion in the cylinder, in the exhaust system, and after the tailpipe. Specific mechanisms include the injection of fuel, formation and oxidation of particles during combustion, exhaust gas recirculation (EGR), and condensation of semi‐volatiles. The role of fuels is discussed with respect to their ignition behavior as a consequence of mixture preparation in the cylinder and with respect to their sooting propensity. Models for the formation, growth, and oxidation of soot particles are presented and the most popular mathematical approaches for simulating particle emissions are introduced. Solid and semi‐volatile nucleation mode particles are also discussed in some detail. Key drivers in the formation of these particles are sulfur in the fuel and lubricating oil and metals in the lubricating oil. Particle emissions of different types of gasoline engines with and without aftertreatment are also discussed and compared with diesel engine emissions. Some of the shortcomings of the current models and future research areas are highlighted at the end.

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Diesel Exhaust Particle Size: Measurement Issues and Trends

Cited by 221 publications

References 16 publications

Combustion Aerosols: Factors Governing Their Size and Composition and Implications to Human Health

Combustion Aerosols: Factors Governing Their Size and Composition and Implications to Human Health

Bipolar Diffusion Charging of Aggregates

Particle Formation and Models

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