• 한국자동차공학회논문집
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• 제15권3호
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• pp.35-40
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• 2007

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engine are recognized main cause which influenced environment strong, In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated common rail diesel engine. The smoke emission of biodiesel fuel 5vol-%(min. content) was reduced in comparison with diesel fuel, that is, it was reduced approximately 60% at 4000rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, NOx emission of biodiesel fuel was increased compared with a 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 biodiesel fuel(5vol-%) and cooled EGR method($5{\sim}10%$) in a common rail diesel engine.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.65-71
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• 2005

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions of diesel engine are recognized main cause which influenced environment strong. In this study, the potential possibility of biodiesel fuel was investigated as an alternative fuel for a naturally aspirated D.I. diesel engine. The smoke emission of biodiesel fuel was reduced remarkably in com parison with diesel fuel, that is, it was reduced approximately 48.5% at 2500rpm, full load. But, power, torque and brake specific energy consumption didn't have no large differences. But, $NO_X$ emission of biodiesel fuel was increased com pared with commercial diesel fuel. Also, the effects of exhaust gas recirculation(EGR) on the characteristics of $NO_X$ emission has been investigated. It was found that simultaneous reduction of smoke and $NO_X$ was achieved with biodiesel fuel(20vol-%) and cooled EGR method($5{\sim}15%$).

• 대한기계학회논문집B
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• 제30권3호
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• pp.208-214
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• 2006

Dimethoxy methane$(CH_3-O-CH_2-O-CH_3)$, also known as methylal or DMM, is an oxygenated additive that contains 42.5% oxygen by weight and is soluble in diesel fuel. It is a colorless liquid and a gas-to-liquid chemical 방tat has been evaluated for use as a diesel fuel component. Experiments were conducted by using the five blends with different volumetric percentage of DMM(2.5, 5, 7.5, 10, and 12.5%) in baseline diesel fuel. The test engine was single cylinder, four stroke, DI diesel engine unmodified. Also, data was collected for steady state operation at 24 engine speed-load conditions. The focus of this study was to investigate the effects of the addition of oxygenated fuel to diesel fuel on the engine-out emissions and the performance. Smoke emissions of all DMM blends were reduced substantially in comparison with conventional diesel fuel. These results indicate that DMM may be an effective blendstock for diesel fuel as an environment-friendly alternative fuel. Besides, this study showed that simultaneous reduction of smoke and NOx emissions could be achieved by oxygenated fuel and EGR method that was applied to decrease NOx emissions increasing with smoke emissions reduction.

• 한국정밀공학회지
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• 제25권11호
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• pp.83-89
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• 2008

The Effect of Space Velocity(SV) on NOx conversion rate was performed to develop NOx reduction after-treatment system. SV is calculated from engine exhaust gas volume and SCR catalyst volume. Found the Urea injection duty of maximum efficiency for NOx conversion if increase SV, NOx Conversion rate is down. Especially, when SV is more than $110,000h^{-1}$, NOx conversion rate decrease suddenly. Same case, if SV is lower than $40,000h^{-1}$, NOx conversion rate is down. Also, the characterization of Urea-SCR system was performed. Three candidate injectors for injecting Urea were tested in terms of 속 injection rate and NOx reduction rate. The performances of SCR catalytic converter on temperature were investigated. The performance of Urea-SCR system was estimated in the NEDC test cycle with and without EGR. It was found that nozzle type injector had high NOx conversion rate. SCR catalytic converter had the highest efficiency at the temperature of $350^{\circ}C$. EGR+Urea-SCR system achieved NOx reduction efficiency of 73% through the NEDC test cycle.

• 한국자동차공학회논문집
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• 제10권3호
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• pp.28-35
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• 2002

The objective of this paper is to quantitatively investigate the effects of alcohol mixture on the combustion improvement of main fuel in supplying alcohol to direct injection diesel engine by auxiliary injection method and blend method. If alcohol is supplied, engine performance greatly improves in high load range. In case of supplying ethanol, BSFC improves, the emission of smoke and NO decreases by delaying main fuel injection timing 5$\^{C}$A. The maximum delivery quantity of alcohol is limited to approximately 50% of total fuel delivery due to misfire and knocking. The limit quantity of main fuel injection that does not accompany misfire and the deterioration of BSFC was approximately 15∼18.5mg/st.

• Journal of Advanced Marine Engineering and Technology
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• 제25권6호
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• pp.1244-1249
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• 2001

The characteristics of engine performance with fuel injection system in D.I. diesel engine were studied in this paper A fuel injection system has an important role in the performance and emission gas in a diesel engine. In this paper, an experimental study has been performed to verify the effect of the performance and the emission gas with the factors such as diameters of an injection nozz1e hole, diameters of an injection pipe and injection timing in the fuel injection system. The authors have obtained the results that optimizing the factors of fuel injection system is siginificant to enhance the performance of the engine system and consumption ratio of fuel, smoke, and NOx.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.43-50
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• 2002

In the present study, reduction of harmful exhaust gas in a diesel engine using stratified injection system of dual fuel (diesel fuel and methanol) was tried. The nozzle and fuel injection pump of conventional injection system were remodeled to inject dual fuel in order from the same injector. The quantity of each fuel was controlled by micrometers, which were mounted at rack of injection pumps. The injection ratio of dual fuel was certificated by volumetric ratio in injection quantity test. Cylinder pressure and exhaust gas were measured and analyzed under various supply condition of duel fuel. We confirmed that combustion of dual fuel was performed successful1y by using modified injection system in a D.I. diesel. Soot and NOx are simultaneously reduced by stratified injection without large deterioration of thermal efficiency, but THC and CO are relatively increased.

• 한국분무공학회지
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• 제6권3호
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• pp.32-37
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• 2001

The characteristics of engine performance with fuel injection system in D.I. diesel engine were studied in this paper. A fuel injection system has an important role in the performance and emission gas in a diesel engine. In this paper, an experimental study has been performed to verify the effect of the performance and the emission gas with the factors such as diameters of an injection nozzle hole, diameters of an injection pipe and injection timing in the fuel injection system. The authors have obtained the results that optimizing the factors of fuel injection system is significant to enhance the performance of the engine system and consumption ratio of fuel, smoke, and NOx.

• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.356-363
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• 1997

Many research works have been carried out to investigate the factors governing the performance of diesel engine. The area of the study has been focused on reducing both of NOx and smoke because of many difficulties to reduce them simultaneously in diesel engines. One of the efforts is an application of EGR technology to reduce NOx emission, which is very effective, but increases other emissions and makes fuel economy worse. In order to solve the problem, EGR is employed with water emulsified fuel and tested in this paper. Emulsified fuel is produced by centrifugal mixer and the amount of water is controlled by water injector and pulse generator, and EGR rate is controlled with 6-step control valve. The chamber pressure, fuel consumption and emissions are measured with various values of both EGR and water mixing rate, The results show that NOx emission is reduced much rather and smoke is also reduced simultaneously.

• Journal of Advanced Marine Engineering and Technology
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• 제31권8호
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• pp.904-910
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• 2007

In this study an experimental research has been conducted to reduce NOx and smoke emission from diesel engine exhaust gas simultaneously by application of corona discharge type electrostatic precipitator(ESP). The ESP was installed between exhaust gas silencer and outlet terminal of exhaust gas system. The operating conditions as input parameters taken in this experiment were corona power input, gas velocity and equivalence ratio of gas. It was found that the corona discharge type ESP has notable effect on reducing smoke in exhaust gas but appeared to bring slight effect on reducing NOx.