• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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• pp.75-82
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• 2002

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(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 device with a cylinder-type scrubber which has five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to study the effect of intake mixture temperature, a intake mixture heating device which has five heating coils is made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that NOx emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2002년도 추계학술대회 발표 논문집
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• pp.100-111
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• 2002

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle, four-cylinder, swirl chamber type, water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas recirculation(EGR) control system for reducing $NO_x$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $NO_x$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection, however, would be included within those of scrubber EGR system. In order to survey the effect of intake mixture temperature on performance and exhaust emissions, the intake mixtures of fresh air and recirculated exhaust gas are heated by a heating device with five heating coils made of a steel drum. It is found that the specific fuel consumption rate is considerably elevated by the increase of intake mixture temperature, and that $NO_x$ emissions are markedly decreased as EGR rates are increased and intake mixture temperature is dropped, while soot emissions are increased with increasing EGR rates and intake mixture temperature. Thus one can conclude that the performance and exhaust emissions are considerably influenced by the cooled EGR.

• Journal of Advanced Marine Engineering and Technology
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• 제28권2호
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• pp.315-331
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• 2004

The effects of intake mixture temperature on performance and exhaust emissions under four kinds of engine loads were experimentally investigated by using a four-cycle. four-cylinder. swirl chamber type. water-cooled diesel engine with scrubber EGR system operating at three kinds of engine speeds. The purpose of this study is to develop the scrubber exhaust gas Recirculation (EGR) control system for reducing $\textrm{NO}_{x}$ and soot emissions simultaneously in diesel engines. The EGR system is used to reduce $\textrm{NO}_{x}$ emissions. And a novel diesel soot-removal device of cylinder-type scrubber with five water injection nozzles is specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The influences of cooled EGR and water injection. however. would be included within those of scrubber EGR system. In order to survey the effects of cooled EGR and moisture on $\textrm{NO}_{x}$ and soot emissions. the intake mixtures of fresh air and recirculated exhaust gas are heated up using a heater with five heating coils equipped in a steel drum. It is found that intake and exhaust oxygen concentrations are decreased, especially at higher loads. as EGR rate and intake mixture temperature are increased at the same conditions of engine speed and load. and that $\textrm{NO}_{x}$ emissions are decreased. while soot emissions are increased owing to the decrease in intake and exhaust oxygen concentrations and the increase in equivalence ratio. Thus ond can conclude that $\textrm{NO}_{x}$ and soot emissions are considerably influenced by the cooled EGR.

• International Journal of Automotive Technology
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• 제7권6호
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• pp.675-680
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• 2006

In the direct injected gasoline engine, atomized spray is desired to achieve efficient mixture formation needed to good engine performance because the injection process leaves little time for the evaporation of fuels. Therefore, substantial understanding of global spray structure and quantitative characteristics of spray are decisive technology to optimize combustion system of a GDI engine. The combustion and emission characteristics of gasoline-fueled stratified-charge compression ignition(SCCI) engine according to intake temperature and compression ratio was examined. The fuel was injected directly to the cylinder under the high temperature condition resulting from heating the intake port. With this injection strategy, the SCCI combustion region was expanded dramatically without any increase in NOx emissions, which were seen in the case of compression stroke injection. Injection timing during the intake temperature was found to be an important parameter that affects the SCCI region width. The mixture stratification and the fuel reformation can be utilized to reduce the required intake temperature for suitable SCCI combustion under each set of engine speed and compression ratio conditions.

• 한국자동차공학회논문집
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• 제14권3호
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• pp.1-9
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• 2006

Recently, there has been an interest in premixed diesel engines as it has the potential of achieving a more homogeneous and leaner mixture close to TDC compared to conventional diesel engines. Because this concept reduced NOx and smoke emissions simultaneously. Early studies are shown that in a HCCI(Homogeneous Charge Compression Ignition) engine, the fuel injection timing and intake air temperature affect the mixture formation. The purpose of this study is to investigate characteristics of combustion and mixture formation according to injection timing and intake air temperature in a common rail direct injection type HCCI engine using an early injection method called the PCCI(Premixed Charge Compression Ignition). From this study, we found that the fuel injection timing and intake air temperature affect the mixture formation and in turn affects combustion in the PCCI engine.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.101-102
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• 2014

Rising oil price and environmental problems are causing automotive industry to increase fuel efficiency. Improved fuel efficiency in gasoline engine was made possible by development of DISI gasoline engine. Since fuel is injected inside cylinder directly, in-cylinder temperature can be reduced than multi-port injection engine and this leads to increased compression ratio. However, engine performance is largely dependent on mixture formation process due to in-cylinder fuel injection. Especially for spray guided and air guided DISI gasoline engine, injection direction is important factor to mixture preparation. It is because interaction between intake flow and spray affect fuel-air mixture. Hence, in this study, mixture formation characteristics were analyzed by varying injection direction using KIVA 3V release2 code. Residual gas was considered for assuming combustion. Therefore, initial condition for in-cylinder temperature was set equal to the end state of exhaust stroke of combustion cycle. Since angle between intake air flow direction and spray direction affects fluid flow and evaporation field, mixture distribution was affected by fuel injection direction dominantly.

• 한국자동차공학회논문집
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• 제5권5호
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• pp.51-66
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• 1997

A heat transfer model of the intake valve in a spark ignition engine is presented, which is calibrated with a number of the valve temperature profiles measured during engine warm-up for the gaseous fuel(propane). The valve is divided into four identical elements for which the assumption of lumped thermal mass is applied. The calibration is made so that the difference between the measued and simulated valve temperatures becomes minimal. Then the model is applied to the cases of the liquid fuel(indolene) to estimate the amount of the liquid fuel vaporized from the intake valve by assuming that fuel evaporation accounts for the deficit of the heat balance budget. The results of the model show quantitative contribution of each heat transfer source to the heat balance. The behavior of the calculated mass fraction of the fuel vaporized from the intake valve explains how the liquid fuel evaporate during engine warm-up. The mass fraction at warmed-up condition is closely related with the fraction directly targeted on the valve back by the fuel spray geometry.

• 한국자동차공학회논문집
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• 제7권8호
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• pp.107-115
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• 1999

Hydrocarbon emission from spark ignition engines deeply relates with fuel evaporation mechanism. Therefore, fuel evaporation on the back of the intake valve is very important to understand fuel evaporation mechanism during engine warm up period. Intake valve heat transfer model was build up to estimate the amount of fuel evaporation on the intake valve back . Intake valve temperature was measured intake valve temperature is increased rapidly during few seconds right after engine start up and it takes an important role on fuel evaporation. The liquid fuel evaporation rate on the intake valve back proportionally increases as valve temperature increases, however its contribution slightly decreases as intake port wall temperature increases. The fuel evaporation rate on the valve back is about 40∼60% during engine warm-up period and it becomes about 20∼30% as intake port wall temperature increases. The estimation model also makes possible model also makes possible to review the effect of valve design parameters such as the valve mass and seat area on fuel evaporation rate through intake valve heat transfer.

• 한국자동차공학회논문집
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• 제14권2호
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• pp.121-126
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• 2006

A gasoline-fueled stratified charge compression ignition (SCCI) engine with both direct fuel injection and intake temperature and compression ratio was examined. The fuel was injected directly by using the high temperature resulting from heating intake port. With this injection strategy, the SCCI combustion region was expanded dramatically without any increase in NOx emissions which were seen in the case of compression stroke injection. Injection timing during the intake temperature was found to be an important parameter that affects the SCCI region width. The effect of mixture stratification and the effect of fuel reformation can be utilized to reduce the required intake temperature for suitable SCCI combustion under each set of engine speed and compression ratio conditions.

• 한국초지조사료학회지
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• 제16권4호
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• pp.267-274
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• 1996

This experiment was carried out to investigate the effect of pasture types(mixture and mono tall fescue pasture) and endophyte infection on the animal behavior of Korean native cattle at the Experimental Field of Grassland and Forage Crops Division, National Livestock Research Institute, Suweon, in 1994. The results obtained are sumunarized as follows: DM intake of Korean native cattle was increased with mixture and endophyte-free tall fescue for both pasture types. Mixture and endophyte-free tall fescue showed good animal preference. Daily grazing time was increased with mixture and endophyte-free tall fescue in monoculture, while annual grazing period was increased with monoculture and endophyte-infect tall fescue. Amount of drinking water of Korean native cattle was increased with tall fescue monoculture rather than mixture, however the amount of drinking water was higher with endophyte-infect tall fescue in monoculture. Salt intake of Korean native cattle was increased with mixture and endophyte-6ee tall fescue in monoculture. Rectal temperature of Korean native cattle was not influenced by pasture types and endophyte infection. Based on the results of this experiment, DM intake of Korean native cattle and daily grazing time were increased by mixture and endophyte-free tall fescue with good quality.