• Journal of Mechanical Science and Technology
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• v.19 no.12
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• pp.2253-2262
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• 2005

The focus of this work is placed on the analysis of the mixture formation mechanism under the evaporative diesel spray of impinging and free conditions. As an experimental parameter, ambient gas density was selected. Effects of density variation of ambient gas on liquid and vapor-phase inside structure of evaporation diesel spray were investigated. Ambient gas density was changed between ${\rho}a=5.0\;kg/m^3$ and $12.3\;kg/m^3$. In the case of impinging spray, the spray spreading to the radial direction is larger due to the decrease of drag force of ambient gas in the case of the low density than that of the high density. On the other hand, in the case of free spray, in accordance with the increase in the ambient gas density, the liquid-phase length is getting short due to the increase in drag force of ambient gas. In order to examine the homogeneity of mixture consisted of vapor-phase fuel and ambient gas in the spray, image analysis was conducted with statistical thermodynamics based on the non-dimensional entropy (S) method. In the case of application of entropy analysis to diesel spray, the entropy value always increases. The entropy of higher ambient density is higher than that of lower ambient gas density during initial injection period.

• Environmental Engineering Research
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• v.22 no.3
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• pp.294-301
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• 2017

This paper is based on experiments conducted on a stationary, four stroke, naturally aspirated air cooled, single cylinder compression ignition engine coupled with an electrical swinging field dynamometer. Instead of 100% diesel, 20% Jatropha oil methyl ester with 80% diesel blend was injected directly in engine beside 25% pre-mixed charge of diesel in mixing chamber and with 20% exhaust gas recirculation. The performance and emission characteristics are compared with conventional 100% diesel injection in main chamber. The blend with diesel premixed charge with and without exhaust gas recirculation yields in reduction of oxides of nitrogen and particulate matter. Adverse effects are reduction of brake thermal efficiency, increase of unburnt hydrocarbons (UBHC), carbon monoxide (CO) and specific energy consumption. UBHC and CO emissions are higher with Diesel Premixed Combustion Ignition (DPMCI) mode compared to compression ignition direct injection (CIDI) mode. Percentage increases in UBHC and CO emissions are 27% and 23.86%, respectively compared to CIDI mode. Oxides of nitrogen ($NO_x$) and soot emissions are lower and the percentage decrease with DPMCI mode are 32% and 33.73%, respectively compared to CIDI mode.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• Journal of the Korean Institute of Gas
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• v.11 no.1 s.34
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• pp.9-12
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• 2007

In this study, a new method of combustion characteristics have been proposed to reduce exhaust emissions in a diesel engine using four kinds of mixed fuel. Mixed fuels show four different torque ratios between diesel oil md natural gas, which are 4:0, 3:1, 2:2 and 1:3. In order to investigate the exhaust gas during combustion, exhaust gases are sampled by gas analyzer, for example NOx, Soot, CO, and HC, as the RPM changed. As a result, the NOx, CO, and HC concentrations of mixed fuel are higher than those of diesel oil only. However, the Soot concentration of mixed fuel is lower when diesel oil is burned.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.12
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• pp.1691-1698
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• 2003

In this paper, the combination effects of oxygen component in fuel and exhaust gas recirculation on the exhaust emissions have been investigated for a direct injection diesel engine. It is a kind of effective oxygenated fuel of diether group that the smoke emission of DGM(diethylene glycol dimethyl ether) blended fuel is reduced remarkably compared with commercial diesel fuel, that is, it can supply oxygen component sufficiently at higher loads and speeds in diesel engine. But, NOx emission of oxygenated fuel was increased compared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) on the characteristics of NOx emission has been investigated. It was found that simultaneous reduction of smoke and NOx was achieved with oxygenated fuel(DGM 5vol-%) and cooled EGR method(10∼15%).

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.8-17
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• 2002

In this study, it was tried to analyze not only total hydrocarbon but individual hydrocarbon components from C$_1$to C$\sub$6/ in exhaust gas using gas chromatography to seek the reason fur remarkable differences of smoke emission of diesel fuel, esterfied rice bran oil and blended fuel(esterfied rice bran oil 20vo1-% + diesel fuel 80vo1-%). Individual hydrocarbons(C$_1$ ∼C$\sub$6/) as well as total hydrocarbon of esterfied rice bran oil is reduced remarkably compared with diesel fuel. Although smoke emission of esterfied rice bran oil reduced remarkably compared with commercial diesel fuel, NOx emission of esterfied rice bran oil and blended fuel was increased slightly at high loads and speeds. And, it was tried to reduced NOx emission of them by exhaust gas recirculation(EGR) method. Simultaneous reduction of smoke and NOx emission was achieved with the combination of esterfied rice bran oil and EGR method in consequence.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.98-103
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• 2007

The number of vehicles employing diesel engines is rapidly rising. Accompanying this trend, application of an after-treatment system is strictly required as a result of reinforced exhaust regulations. The Diesel Particulate Filter (DPF) system is considered as the most efficient method to reduce particulate matter (PM), but the improvement of a regeneration performance at any engine operation point presents a considerable challenge by itself. Temperature, gas compostion and flow rate of exhaust gas are important parameters in DPF evaluation, especially regeneration process. Engine dynamometer and degment tester are generally used in DPF evaluation so far. But these test method couldn't reveal the effect of various parameters on real DPF, such as O2 concentration, amount of soot and exhaust gas temperature. This research has studied the possibility using dump combustor that used to take an approach lean premixed combustion in gas turbine for a DPF power and optimized. It is possible that utilize the system as DOC (Diesel Oxidation Catalyst) and SCR(Selective Catalytic Reduction) assessments test as well as DPF evaluation

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.151-152
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• 2012

Collectors connected to diesel engine exhaust pipe for application of PM reduction facilities which was used to reduce PM from the exhaust gas produced from ship, Filtration performance of PM was tested. In this system, it was confirmed that the bag house can remove over 90 percent of PM from a lot of high temperature and high pressure gases produced in diesel engine. The results obtained from performance test show the potential possibility for commercialization of ceramic filter collectors which is applied to reduction facilities of flue gas produced from a diesel engine on the ship.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.138-142
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• 1998

Among aftertreatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects of low sulfur diesel fuel in heavy duty diesel engine equipped with DOC. We tested to estimate change of engine performance for the low and high sulfur diesel fuels in a 11,000cc diesel engine equipped with DOC. We conducted test to estimate the reduction efficiency of exhaust gas in D-13 mode of heavy duty diesel regulation mode and in smoke opacity mode for two samples of high sulfur content (0.2%) and low sulfur content(0.05%)

• Journal of Auto-vehicle Safety Association
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• v.10 no.3
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• pp.27-31
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• 2018

The People have a bad perception about diesel vehicle because of serious air pollution, increase fine dust and global vehicle company's diesel gate. Starting the project in 2005, Ministry of Environment has been supporting that is exhaust gas reduction devices (DPF) on diesel vehicles in the metropolitan area. During the period of 2017.01.01 to 2017.12.31, 10,030 diesel vehicles installed exhaust gas reduction devices (DPF). Among them, 9,921 diesel vehicles that they have sufficient data for analysis were analyzed amount of particulate matter reduction before and after exhaust gas reduction devices (DPF) was installed. Opacity smoke meter measures the concentration of particulate matter. So concentration of particulate matter was converted into a mass unit, and then calculated the total amount of reduced particulate matter. It was estimated that social benefits is costs required to remove it from the total amount of particulate matter.