• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.405-411
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• 1999

Dynamic effect of gas in exhaust manifold influences the volumetric efficiency of the engine. Especially in case of multi-cylinder engine the shape of exhaust manifold is important for the opti-mum design of exhasut manifold complicated. In this paper the effects of exhaust manifold systems on volumetric efficiency were investigated for the 4 cylinder 4 stroke-cycle diesel engine. Volumetric efficiency was calculated by the method of characteristics. The calculation results coincided well the test results. This study showed that the appropriate position and diameter of exhaust manifold branch are important factors in increasing volumetric efficiency and decreasing pumping loss.

• 한국세라믹학회지
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• 제45권9호
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• pp.497-506
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• 2008

The long time of twenty years has passed since Diesel Particulate Filter (DPF) was proposed before the practical use. The main factors that DPF has been put to practical use in this time, are the same time proposal of the evaluation method of SiC porous materials linked to he performance on the vehicle, and that the nature of thermal shock required for the soot regeneration (combustion of soot) in the DPF is different from the conventional requirement for the rather rapid thermal shock. For the requirements, these includ demonstrating utmost the characteristic of SiC's high thermal conductivity, and overcoming the difficulty of thermal expansion of SiC-DPF by dividing the filter into segments binding with the cement of lower Young's modulus, and the innovation of technology around the diesel exhaust system such as Common-Rail system. As the results of these, the cumulative shipments of SiC-DPF have reached about 5 million, and it goes at no claim in the market.

• Journal of Advanced Marine Engineering and Technology
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• 제28권6호
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• pp.894-905
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• 2004

The closed cycle diesel propulsion system is free from the problem of the intake air, exhaust gas and their control that are associated with the conventional diesel propulsion system. The system is composed of a main engine, an exhaust cooler. a $CO_2$ scrubber and a $O_2$ mixer. In this paper, a hardware using microprocessor is proposed in order to monitor and control the oxygen and ratio of specific heat for underwater diesel propulsion system. Also simulation is carried out to ascertain the performance of proposed system.

• 한국공작기계학회논문집
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• 제15권1호
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• pp.76-81
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• 2006

Modem after-treatment technology has been developed variously in order to decrease exhausted emission in diesel engine. However, it seems very difficult to comply with updated stringent emission standards. Specially, it has been many years that exhaust gas from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx and PM among those compositions. Thus, this research focused on the electronic control EGR and the target for this research is heavy-duty turbo-diesel engine with EGR technology(High pressure route and low pressure route system).

• 한국자동차공학회논문집
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• 제10권3호
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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.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.179-189
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• 1997

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 studied actively. In this study, a transient one-dimensional model developed to simulate the thermal and conversion characteristics of adiabatic monolithic converters operating under warm up conditions is presented. This model takes into account the gas solid heat and mass transfer, axial heat conduction, chemical reactions and the related heat release. The model has been used to analyze the transient response of an axisymmetric catalytic converter during a warm-up as a function of catalyst design parameters and operation conditions in order to observe their effects on the lightoff behaviour. The experimental test was carried out 2400 cc light diesel engine with DOC.

• 한국자동차공학회논문집
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• 제10권4호
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• pp.60-68
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• 2002

Experiments have been conducted to investigate the effects of emulsified fuels on the spray characteristics and exhaust emissions in a diesel engine. Four different fuels were examined : diesel, emulsified fuels with water contents which were varied with 13, 15, and l7wt%. Characteristics of fuel spray were measured by an optical method, PLLIF(planar liquid laser induced fluorescence). Compared to diesel fuel, emulsified fuels which had relatively high kinematic viscosity showed smaller spray angle and longer spray tip penetration. The qualitative droplet distributions of emulsified fuels showed worse atomization process than that of diesel fuel. As the water contents were increased, PM and NOx could be reduced simultaneously. It was specially noted that the emulsified fuel with l7wt% water content was found to be the best in reducing rates, NOx 30% and PM 40%.

• Journal of Advanced Marine Engineering and Technology
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• 제36권7호
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• pp.885-893
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• 2012

DME (Dimethyl ether) is regarded as one of the candidates of alternative fuels for diesel engine, because of its higher cetane number suitable for a compression ignition engine. Also, DME is a simple chemical structure, colorless gas that is easily liquefied and transported. On the other hand, Bunker oil (JIS C heavy oil) has long been used as a basic fuel in marine diesel engines and is the lowest grade fuel oil. In this study, the combustion and emission characteristics were measured experimentally in the direct injection type diesel engine operated with DME and Bunker oil mixed fuel. From our experimental results, it is induced that DME and Bunker oil blended fuel would be an effective fuel which can reduces the concentration of harmful matter in exhaust gases.

• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.16-24
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• 2000

In this study, using frying oil, performance of engine and emission concentration were compared with the case of using diesel oil. And results are as follows. 1. Engine torque and brake horse power indicate nearly same value as the case of using diesel fuel. 2. Temperature of exhaust gas was increased with as high engine speed and load. 3. To reduce concentration of hydrocarbon, it is effective to operate using used frying oil in low engine speed and load, and adding LPG in high engine speed and load. 4. Concerning with concentration of carbon mono oxide and smoke emission, it was assured, that as engine load increased, lower concentration emitted in case of utilizing mixed fuel than that of utilizing pure diesel fuel.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.47-56
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• 2001

Nitrogen oxides(NOx) and smoke emissions of diesel engine are regarded as a source of air pollution, and there is a global trend to enforce more stringent regulations on these exhaust gas emissions. However, the trade-off relation of NOx and smoke is a main obstacle to reduce both of them simultaneously. In this paper, experiments were conducted with an oxygenated fuel(diethyl ether) as an effective way to improve the trade-off relation of NOx and smoke. Exhaust emissions of diesel fuels with DEE were influenced by the additive content of DEE and the injection timing. Especially, DEE effected more at the high engine speed and load than at the low engine speed and load. Diesel fuel blended with DEE 10% was a desirable blend for the simultaneous reduction of NOx and smoke.