• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.9
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• pp.1117-1123
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• 2004

The characteristics of soot near the soot inception point for an ethene-air flame was carried out in a WSR (well-stirred reactor). The new sampling tool like the temperature controlled filter system was introduced to minimize the condensation during sampling. The new analysis tools applied include the real time size distribution analysis with the Nano-DMA, particle size by transmission electron microscopy, C/H analysis, g filter analysis, and thermogravimetric analysis using both non-oxidative and oxidative pyrolysis. The WSR can generate young soot particles that can be collected and examined to gain insight into inception. For the current conditions, soot does not form for ${\Phi}$=1.9, inception occurs at or before ${\Phi}$=2.0, and inception combined with soot surface growth and/or coagulation occurs for ${\Phi}$=2.1. The filter samples for ${\Phi}$=1.9 are composed of volatile compounds that evolve at relatively low temperatures when heated in the presence or absence of O$_2$. The samples collected from the WSR at ${\Phi}$=2.0 and ${\Phi}$=2.1 are precursor-like in morphology and size. They have higher C/H ratios and lower organic percentages than precursor particles, but they are clearly not fully carbonized soot. The WSR PAH distribution is similar to that in young soot from inverse flames.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.5
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• pp.725-732
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• 2000

Laser induced incandescence (LII) method is frequently used to measure soot volume fraction in flames. In this study, experiments were performed to measure soot volume fraction in coaxial diffusion flame using LII method and calibrated with laser scattering/extinction method. The effects of laser intensity (>$1{\times}10^8W/cm^2$), laser wavelength (532nm, 1064nm) and detection wavelength (400nm, 600nm) on the LII signal were investigated. On the range of $4{\times}10^8{\sim}8{\times}10^8W/cm^2$ there were no effects of laser intensity on LII signal. Except these ranges, LII signal was increased with laser intensity. For the long gate width, the LII signals of the higher laser intensity (>${\vartheta}(GW/cm^2)$) cases had better correlation with soot volume fraction which were measured by laser extinction method compared with lower laser intensity cases. The errors of 2-dimensional cases at the calibration height were approximately 50% regardless of laser wavelength.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.70-78
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• 2000

The effects of recirculated exhaust gas on the characteristics of ;$NO_x$ and soot emissions under a wide range of engine load have been experimentally investigated by a water-cooled, four-cylinder, indirect injection, four cycle and marine diesel engine operating at two kinds of engine speeds. The purpose of the present study is to develop the EGR control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal apparatus with a cylinder-type scrubber for the experiment system which has 6 water injectors(A water injector is made up 144 nozzles with 1.0mm in diameter) is specially designed and manufactured to reduce the soot contents in the recirculated exhaust gas to intake system of the engines. The intake oxygen concentration obtained by the intake air flow and the oxygen concentration in the recirculated exhaust gas, and the exhaust oxygen concentration measured in exhaust manifold are used to analyse and discuss the influences of EGR on NOx and soot emissions. The experiments are performed at the fixed fuel injection timing of $15.3^{\circ}$ BTDC regardless of experimental conditions. It is found that $NO_x$ emissions decrease and soot emissions increase owing to the drop of intake oxygen concentration and exhaust oxygen concentration as EGR rate rises. Also, one can conclude that it is sufficient for the scrubber EGR system with a novel diesel soot removal apparatus to reduce $NO_x$ emissions, but not to reduce soot emissions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.518-524
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• 2013

In this study, we conducted a study on characteristics of exhaust gas emissions from boiler when water-bunker oil mixed by homogenizer was burned in boiler. The results showed that NOx concentration and CO concentration of the homogenized bunker oil was decreased by 19% and 54% compared to pure bunker oil pretreatment was not being performed. And, in the case of water-bunker A oil, the NOx concentration was decreased with increasing water mixing ratio in bunker A oil. In particular, the NOx concentration in exhaust gas of 20 %water-80 %bunker A oil decrease by 45 % compared with pure bunker-A. However, the CO concentration in exhaust gas of 20 %water-80 %bunker A oil shows irregular changes. This means that the mixing of water more than a certain amount can cause a decrease in combustion performance. From this result, it can be found that critical mixing ratio of water in bunker A oil for normal combustion is 15% in this study. Deposition amount of soot that is collected in the vicinity of the chimney was decreased with increasing water mixing ratio.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.10a
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• pp.62-65
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• 2008

In this paper, we estimated the D147 mode test, which is introduced as a new emission test mode for the driving car using diesel fuel. And we compared the D147 test mode, Lug-Down3 test mode and no load acceleration test mode. And the exhaust gas concentration between the three modes was compared. The exhaust concentration at the D147 mode is lower than the exhause concentration at the Lug-Down 3 mode and higher than that at the no load acceleration test mode. Also the correlation factor was estimated between the D147 mode and Lug-Down 3 mode.

• Journal of ILASS-Korea
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• v.21 no.3
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• pp.162-169
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• 2016

When we construct a road near an apartment complex, we consider a soundproof wall. To make residential places quieter, we may consider a soundproof road tunnel. Such a tunnel, however, would become highly concentrated with soot from vehicles whenever a traffic jam might occur. To create an optimum design, this study utilizes the PHOENICS-VR software. The work considers three cases: (1) no openings (2) openings at 30m intervals, and (3) openings at 60m intervals on the upper side of the tunnel. The study finds that in the second case shows CO concentration distributions were 15% less than those without openings. And the CO concentration distributions of the second and third cases are almost the same. The findings suggest that we should make the soundproof tunnel to reduce construction fees.

• Journal of the Korean Vacuum Society
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• v.15 no.5
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• pp.506-511
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• 2006

ZnO nanorods were prepared by the hydrothermal reaction of a solution containing $Zn(NO_3)_2{\cdot}6H_2O$, NaOH, cyclohexylamine, ethanol and water, and their $NO_2$ and CO sensing behaviors were investigated. By the control of water concentration in solution, the morphology and agglomeration of ZnO nanorods could be manipulated, which is associated with the variation of $[OH^-]$ resulted from an interaction between water and cyclohexylamine. Sea-urchin-like and well-dispersed ZnO nanorods were prepared at low and high water content, respectively. Well-dispersed ZnO nanorods showed 1.8 fold change in resistance at 1 ppm $NO_2$ while there was no significant change in resistance at 50 ppm CO. This selective detection of $NO_2$ in the presence of CO can be used in automated car ventilation systems.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.116-124
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• 2007

An optical method to measure the size and number density of soot aggregates in diesel exhaust has been proposed in this study. Two laser beams in co-axial alignment transmit a soot loaded exhaust gas flow, and the transmittance at each wavelength is detected by a photo diode simultaneously. The volume equivalent diameter and number density of soot aggregates in the optical path can be theoretically given by the transmittance values measured at two wavelengths. A test conducted by a single cylinder, 4 cycle, small and DI diesel engine shows that the temporal variations of the size and number density of soot aggregates in the diesel exhaust can be measured by the proposed method at a transient mode operation. It is found that the volume equivalent diameter varied temporally from 70 to 110 nm during the period that high soot concentration is observed. One can also conclude that the optical length longer than 1 m in the dynamic range regarding this method is preferable for measuring soot concentration at the level of $1\;mg/m^3$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.196-205
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• 2016

The exhaust gas discharged by cars not only threatens the health of the human body, but also contributes to global warming, due to the resulting increase in the concentrations of ozone, fine dust and carbon dioxide. Therefore, the government has steadily implemented careful inspection systems for exhaust emissions, in order to efficiently regulate the exhaust gas of cars. Studies on reducing the exhaust emissions of automobiles have been conducted in various fields, including ones designed to reduce the generation of HC, NOx, and $CO_2$ in the exhaust emission of vehicles. However, there have been insufficient studies on the reduction of the exhaust emission for old diesel vehicles. To develop careful inspection systems for the exhaust emissions of old diesel vehicles, studies on the reduction of the exhaust emissions and improvement of power are necessary by cleaning the carbon sediment in both the intake manifold and injector. Therefore, in this study, we analyzed and compared the amounts of gas emitted when simultaneously cleaning or not cleaning the intake manifold and injector of diesel automobiles with mileages over 80,000 km and operating periods over 5 years. The experimental results showed that in the case where the intake manifold and injector were simultaneously cleaned, there was a decline of 75.2% in the gas emission compared to the cases where only the manifold or injector is cleaned. Also, it was found that simultaneously cleansing the intake manifold and injector enabled the exhaust standard to be satisfied for less than 30% within 8.5 sec.

• 한국연소학회:학술대회논문집
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• 1997.06a
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• pp.45-50
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• 1997

An experimental study on LII signal images from soot particles in a flame has been carried out in order to investigate the effect of the incident laser characteristics. By changing the wavelength of the incident laser beam, the LII signal was saturated at smaller laser power with 532 nm than 1,064 nm. This implies that the larger absorption coefficient of soot particles at 532 nm would influence the LII signal characteristic. Using the deconvolution technique, the projected LII line images were coverted to reconstruct the local LII signals inside the beam. The results show that the LII images at ICCD camera result from the integration of LII signal across the laser beam.