• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.7
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• pp.113-121
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• 1999

Diesel particulate matter is known to be one of the major harmful emissions produced by diesel engines. Diesel particulates are subject to diesel emission regulations and have lately become the focus in the diesel emission control technology. Thus, the aftertreatment system is adopted at the diesel engine exhaust to reduce the particulate emission. Although this benefit is recognized, it is not clear how the aftertreatment system influences quantitatively the particle size distribution distribution. In this study, the particle size distributions of diesel exhaust were measured using the scanning mobility particle sizer with and without the aftertreatment system. There results showed that the diesel particulate filter and plasm system reduced the number of emitted particles by more than 90% and about 80% respectivley in the particle size range of 20nm∼600nm. On the other hand no significant effect of the diesel oxidation catalyst on the particle number concentration was detected.

• International Journal of Automotive Technology
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• v.8 no.2
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• pp.165-177
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• 2007

Predictions of diesel particulate filtration are typically made by modeling of a particle collection, and providing particle trapping levels in terms of a pressure drop. In the present study, a series of single channel diesel particulate filter (DPF) experiments are conducted, the pressure traces are inversely analyzed and essential filtration parameters are deducted for model closure. A DPF filtration model is formulated with a non-linear description of soot cake regression. Dependence of soot cake porosity, packing density, permeability, and soot density in filter walls on convective-diffusive particle transportation is examined. Sensitivity analysis was conducted on model parameters, relevant to the mode of transition. Soot cake porosity and soot packing density show low degrees of dispersion with respect to the Peclet number and have asymptotes at 0.97 and $70\;kg/m^3$, respectively, at high Peclet number. Soot density in the filter wall, which is inversely proportional to filter wall Peclet number, controls the filtration mode transition but exerts no influence on termination pressure drop. The percolation constant greatly alters the extent of pressure drop, but is insensitive to volumetric flow rate or temperature of exhaust gas at fixed operation mode.

• Journal of Environmental Health Sciences
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• v.32 no.6
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• pp.533-538
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• 2006

The nano-particles are known to influence the environmental protection and human health. The relationships between transient vehicle operation and nano-particle emissions are not well-known, especially for diesel passenger vehicles with DPF(Diesel Particulate Filter). In this study, two diesel passenger vehicles were measured on a chassis dynamometer test bench. The particulate matter (PM) emission of these vehicles was investigated by number and mass measurement. The mass of the total PM was evaluated using the standard gravimetric measurement method, and the total number concentrations were measured on a ECE15+EUDC driving cycle using Condensation Particle Counter (CPC). According to the investigation results, total number concentration was $1.14{\times}10^{11}$M and mass concentration was 0.71mg/km. About 99% of total number concentration was emitted during the $0{\sim}400s$ because of engine cold condition. In high temperature and high speed duration, the particulate matter was increased but particle concentration was emitted not yet except initial engine cold condition According to DPF performance deterioration, the particulate matter was emitted 2 times and particle concentration was emitted 32 times. Thus DPF performance deterioration affects particle concentration more than PM.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.225-236
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• 2004

Diesel engines which emit a lot of PM and NOx have been known as a main air polluter. Especially, diesel particulate matters (OPM) including black smoke are hazardous air pollutants to human health and environment. The nations retaining advanced engine technologies have reinforced emission regulations. To meet these regulations diesel engine manufacturers have developed low-emission diesel engines, aftertreatment equipments, alternative fuel technologies and so on. In this study, particle number concentrations characteristics according to particle size and engine driving conditions were analyzed when these low-emission technologies were applied. There was a tendency of increasing particle number concentrations from heavy-duty diesel engines with increasing engine rpm and load rate. In the cases of COPF (Catalytic Diesel Particulate Filter), CNG (Compressed Natural Gas) engine and ULSD (Ultra Low Sulfur Diesel) more than 99% of particle number concentration were removed.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.4
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• pp.508-514
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• 2010

The objective of this work presented here was experimental study of steadystate and cold start exhaust nano-sized particle characteristics from common rail diesel engine. The effect of the diesel oxidation catalyst (DOC) on the particle number reduction was insignificant, however, particle number concentration levels were reduced by 3 orders of magnitude into the downstream of diesel particulate filter (DPF). In high speed and load conditions, natural regeneration of trapped particle occurred inside DPF and it was referable to increase particle number concentration. As fuel injection timing was shifted BTDC $6^{\circ}CA$ to ATDC $4^{\circ}CA$, particle number concentration level was slightly reduced, however particle number and size was increased at ATDC $9^{\circ}CA$. Nucleation type particle reduced and accumulation type particle was increased on EGR condition.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.994-999
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• 2007

The particulate matters emitted by diesel locomotives cause serious air pollution in stations and railroad. There have been various attempt to reduce the air pollution from diesel bus or trucks. However, the air pollution from the diesel locomotives has been out of control because there has not any adaptable technology. In this study, a diesel particulate filter was developed and applied to the diesel locomotives. A 3,000 horsepower large-scale locomotive and a 1,500 horsepower middle-scale locomotive were used for the test of the filter. The particulate matter emissions before and after the treatment was monitored by a scanning mobility particle sizer and a dust monitor. As a result, it was observed that the particulate matters could be successfully removed from the emission gases by using the filter.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.21-26
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• 2003

Diesel particulate trap is a core technology for the reduction of PM from diesel vehicles This study presents the features and the characteristics of DPF system when using pellet type filters. In comparison with wall-flow filter, the pellet filter has the advantages of cracking free during regeneration and shape flexibility. Experiments are conducted in a test bench simulated as diesel engine exhaust condition. Pressure drop and particle loading rate was compared by using two pellet filters having the porosity of 70% and 0%. Also its regeneration was tested.

• Particle and aerosol research
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• v.4 no.2
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• pp.51-67
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• 2008

In this study, we devoted to kinetic measurement of the catalytic oxidation of iron-containing flame soot particles and better understanding the role of catalytic particles on carbon oxidation in particular at low temperature, targeting on autothermal regeneration of diesel particulate filter by diesel exhaust gas. Carbon-based Fe-containing particles generated by spraying ferrocene-doped diesel fuel in an oxy-hydrogen flame are tested and compared with a commercial carbon black powder for thermogravimetric analysis (TGA), secondary ion mass spectrometry (SIMS), Fourier-transform infrared spectroscopy (FTIR), Induced coupled plasma-Atomic emission spectroscopy (ICP-AES), and High-resolution transmission electron microscopy (HR-TEM). As a result, we found that a small amount of the ferrocene addition led to significant reductions in a on-set temperature and an activation energy of the carbon oxidation as well. An oxygenated surface complex forming at the particle surface could be thought as active species that would be readily consumed in particular at low temperature.

• Particle and aerosol research
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• v.8 no.2
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• pp.55-68
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• 2012

Particulate matters (PM) which are collected into a diesel particulate filter (DPF) system have to be periodically removed by thermal oxidation. In this report, we fabricated an electrohydrodynamic-assisted pressure-swirl nozzle to spray diesel droplets finer. Atomization performance of the nozzle was evaluated using both experimental and numerical methods. Two types of nozzle designs, the charge induction type and the charge injection type, were tested. While the former generated diesel droplets of $400\;{\mu}m$ at an applied electric potential over 10 kV, the latter presented the droplets smaller than $23\;{\mu}m$ at an applied electric potential of 8 kV. The numerical simulation results showed that the reduced size of droplets caused higher evaporation of droplets and therefore the increased temperature, which would eventually increase the regeneration performance of the DPF system.

• International Journal of Naval Architecture and Ocean Engineering
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• v.4 no.4
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• pp.403-411
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• 2012

This study presents the nano-sized particle emission characteristics from a small turbocharged common rail diesel engine applicable to prime and auxiliary machines on marine vessels. The experiments were conducted under dynamic engine operating conditions, such as steady-state, cold start, and transient conditions. The particle number and size distributions were analyzed with a high resolution PM analyzer. The diesel oxidation catalyst (DOC) had an insignificant effect on the reduction in particle number, but particle number emissions were drastically reduced by 3 to 4 orders of magnitude downstream of the diesel particulate filter (DPF) at various steady conditions. Under high speed and load conditions, the particle filtering efficiency was decreased by the partial combustion of trapped particles inside the DPF because of the high exhaust temperature caused by the increased particle number concentration. Retarded fuel injection timing and higher EGR rates led to increased particle number emissions. As the temperature inside the DPF increased from $25^{\circ}C$ to $300^{\circ}C$, the peak particle number level was reduced by 70% compared to cold start conditions. High levels of nucleation mode particle generation were found in the deceleration phases during the transient tests.