The Ignition and Combustion of Cerium Doped Diesel Soot

Stanmore, B. R.; Brilhac, Jean-François; Gilot, P.

doi:10.4271/1999-01-0115

Cited by 43 publications

(20 citation statements)

References 8 publications

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“…The size of the nuclei mode present in the diesel exhaust increases in the presence of metal additives (Kittelson et al 1978;Kytö et al 2002;Matter and Siegmann 1997;Mayer et al 2003). There is an increased interest in putting metal additives in diesel fuel, because doing so lowers the ignition temperature of particles collected in DPFs (Diesel Particulate Filters), and thus enhances regeneration of DPFs (Lahaye et al 1996;Stanmore et al 1999). Skillas et al (2000) and Jung et al (2003Jung et al ( , 2005 found that the nuclei mode increases while the accumulation mode (D p > ∼50 nm) decreases in the presence of metal additives.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Electrical Charge on Diesel Particles

Jung

Kittelson

2005

Aerosol Science and Technology

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Nanoparticles (D p < 50 nm), which are formed as diesel engine exhaust cools and dilutes, constitute minority of total particle mass but majority of total particle number. There are several different theories to explain the nucleation of nanoparticles from diesel exhaust. The two main theories are homogeneous binary nucleation of sulfuric acid and water, and ion-induced nucleation. This study examined the ion-induced nucleation theory. In order to test the ionic nucleation theory, the charged fraction of the diesel particles were measured as a function of particle size using regular diesel fuel in this study. A very small amount of charge was found for the diesel nanoparticles in the nuclei mode, whereas there was a large charged fraction for the diesel particles in the accumulation mode. If ion-induced nucleation were the dominant mechanism for the nucleation of nanoparticles from diesel exhaust, one would expect a significant charge on the nuclei mode particles. The results from this study suggest that ion-induced binary nucleation is at least not a dominant mechanism for the nucleation of diesel exhaust when using regular diesel fuel.This study also examined the influence of metal additives on nucleation and particle charging. The metal additives examined are of the type used to enhance particle oxidation in diesel particulate filters. When used, the additives led to a large increase in the concentration of solid particles in the nuclei mode, and significantly raised the level of particle charge for particles of all sizes. When additives were used, some of the solid particles in the nuclei mode carried a charge. We believe that these metal related particles form early enough in the combustion process to be charged by ions present during and shortly after combustion.

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Section: Introductionmentioning

confidence: 99%

Measurement of Electrical Charge on Diesel Particles

Jung

Kittelson

2005

Aerosol Science and Technology

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“…Measuring the increase in the CO 2 concentrations could confirm the mass loss due to oxidation, but the background concentration of CO 2 in the diluted burner exhaust is too large (~1%) compared to CO 2 produced by soot or carbon atom oxidation (~ 4 ppm). Soot begins to oxidize at roughly 600°C at atmospheric pressure (Stanmore, Brilhac et al 1999;Stanmore, Brilhac et al 2001).…”

Section: Oxidationmentioning

confidence: 99%

Nanoparticle production by UV irradiation of combustion generated soot particles

et al. 2004

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Laser ablation of surfaces normally produce high temperature plasmas that are difficult to control. By irradiating small particles in the gas phase, we can better control the size and concentration of the resulting particles when different materials are photofragmented. Here, we irradiate soot with 193 nm light from an ArF excimer laser. Irradiating the original agglomerated particles at fluences ranging from 0.07 to 0.26 J/cm 2 with repetition rates of 20 and 100 Hz produces a large number of small, unagglomerated particles, and a smaller number of spherical agglomerated particles. Mean particle diameters from 20 to 50 nm are produced from soot originally having a mean electric mobility diameter of 265nm. We use a non-dimensional parameter, called the photon/atom ratio (PAR), to aid in understanding the photofragmentation process. This parameter is the ratio of the number of photons striking the soot particles to the number of the carbon atoms contained in the soot particles, and is a better metric than the laser fluence for analyzing laser-particle interactions. These results suggest that UV photofragmentation can be effective in controlling particle size and morphology, and can be a useful diagnostic for studying elements of the laser ablation process.2

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“…The experiments were like those described precisely by [9,10]: a 10 mg sample of soot was heated to the reaction temperature under inert gas (N 2 ). At time zero, the gas flow was then switched to an O 2 -N 2 mixture.…”

Section: Kineticsmentioning

confidence: 99%