• 해양환경안전학회지
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• 제25권7호
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• pp.953-960
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• 2019

밀러 사이클은 흡입밸브 닫힘 시기 조정을 통해 압축비를 줄임으로써 NOx의 저감과 연료소비율 개선이 동시에 가능하다는 점(밀러 효과)에서 디젤엔진에 매우 활발하게 채택되어지고 있다. 밀러 사이클은 흡입 밸브를 BDC 이전에 닫는 Early 밀러 방식과 BDC 이후에 닫는 Late 밀러 방식으로 나눌 수 있다. 저속에서는 체적효율의 증가를 꾀할 수 있는 Late Miller가 유리한 반면, 중속, 고속에서는 IVC 이후 BDC 까지의 피스톤 하강 과정의 흡기의 팽창에 따른 내부 온도 감소 효과 높은 Early 밀러가 유리하다. 따라서 Early 밀러와 Late 밀러의 효과를 고려하여 운전 조건에 적합한 밀러 구현 방법을 채택할 필요가 있다. 본 연구에서는 4행정 엔진을 대상으로 2단 과급 시스템의 적용하고 흡·배기 밸브 오버랩(valve overlap)의 감소를 통해 밀러 효과를 강화하는 과정과 밸브 조정 기구를 통한 밸브 조건의 변화가 밀러 효과에 미치는 영향을 고찰하였다. 결과적으로 2단과급과 밀러사이클, 밸브 오버랩 감소와 흡입밸브 리프트 증가를 통해 연료소 비율과 최고연소온도 감소의 효과를 확인하였다.

• 한국수소및신에너지학회논문집
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• 제15권2호
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• pp.129-136
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• 2004

환경문제와 석유자원의 고갈이 많은 연구자들을 기존 탄화수소연료를 대체할수 있는 재생 가능한 연료를 구하는데 많은 노력을 기울이고 있다. 수소연료는 유해배기물질이 없는 연소와 또한 연소후에 재생 가능한 물성분만 배출하는 속성으로 미래의 청정에너지로 각광을 받고 있다. 이러한 이유로 수소연료는 수송기계의 연료로도 주목을 받고 있다. 따라서 수소연료기관 개발은 21세기에도 지속적으로 진행될 것이다. 이에대한 초기연구로 기체 LPG 연료가 아닌 액체 LPG 연료를 흡기관에 분사하여 기화된 LPG 연료를 엔진으로 흡입하는 LPi엔진에 수소연료를 과급하여 엔진에 성능을 연구하고자 하였다.

• 한국산업융합학회 논문집
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• 제18권2호
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• pp.110-118
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• 2015

In this study, it is designed and used the test engine bed which is installed with turbocharger, and in addition to equipped using by oxygen adder. It has been controlled the oxygen volumetric fraction of intake air chrge, and supercharged flow rate into the cylinder of SI 4-stroke engine, and then, has been analyzed engine performance, combustion characteristics, and exhaust emission as analysis parameters. The tested parameters were the oxygen fraction and the variation of engine speed and air-fuel ratio.

• 대한기계학회논문집B
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• 제33권4호
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• pp.248-254
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• 2009

The HCCI engine is a next generation engine, with high efficiency and low emissions. The engine may be an alternative to SI and DI engines; however, a pressure rise rate is a major limitation for high load range and power reduction. Recently, we were able to reduce the pressure rise rate using thermal stratification. Nevertheless, this was insufficient to produce high power. In this study, the reduction of the pressure rise rate using thermal stratification was confirmed and the HCCI engine power was increased using the boost pressure. The rate and engine power were produced by CHEMKIN and modified SENKIN. As a result of increasing the boost pressure, a higher IMEP was attained while the pressure rise rate increased only slightly in the HCCI with thermal stratification.

• 동력기계공학회지
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• 제15권6호
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• pp.11-15
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• 2011

This study investigated the symptoms of the a reduction in output while driving on the road, or increasing of fumer out exhaust gas on inclined road while working air-conditioner in summer. Notice how the experiment in 2010, the Ministry of Environment(Chapter No. 2010-46), and how the vehicle emissions inspection was carried out. 2500cc Diesel cars used in the study were used and compare to output of engine, exhaust gas, inhalation temperature measurement Inhalation of cold air has not been supplied to all agencies when comparing the results when cold air intake temperature of the supply air-conditioning switch range control from 1 to 4, the temperature drops $98^{\circ}C$ to $78^{\circ}C$. At the momentum of switch level 4, output from 63ps to 66ps after the connection has increased 9.6 percent, the highest concentration of exhaust emissions were reduced by 42.8%. This research can contribute in part to the reduction of exhaust directly supply into the cooling air intake line, doing the output of diesel cars in the summer. In addition, construction equipment and machinery that are currently being used excluding the engine's intercooler cooling of the supply line via a separate output in the summer and help reduce exhaust emissions is expected.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.899-905
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• 2000

The characteristics of air flow and engine performance with swirl ratio variance of intake port In a turbocharged DI diesel engine was studied in this paper. The intake port flow is important factor which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics. The swirl ratio for ports was modified by hand-working and measured by impulse swirl meter. For the effects on performance and emission, the brake torque and brake specific fuel consumption were measured by engine dynamometer and NOx, smoke were measured by gas analyzer and smoke meter. As a result of steady flow test, when the valve eccentricity ratio are closed to cylinder wall, the flow coefficient and swirl intensity are increased. And as the swirl ratio is increased, the mean flow coefficient is decreasing, whereas the gulf factor is increasing. Also, through engine test its can be expected to meet performance and emission by optimizing the main parameters; the swirl ratio of intake port, injection timing and compression ratio.

• 대한기계학회논문집B
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• 제24권9호
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• pp.1185-1194
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• 2000

The characteristics of intake port flow and engine performance with swirl ratio variance in a turbocharged D.I. diesel engine were studied in this paper. The intake port flow is important factor which have influence on the engine performance and exhaust emission because the properties in the injected fuel depend on the combustion characteristics. Through these experiments it can be expected to satisfy performance and emission by optimizing the main parameters; the swirl ratio of intake port, injection timing and compression ratio. The swirl ratio for ports was modified by hand-working and measured by impulse swirl meter. For the effects on performance and emission, the brake torque and brake specific fuel consumption were measured by engine dynamometer, NOx and smoke were measured by gas analyzer and smoke meter. The results of steady flow test are as follows; as the valve eccentricity ratio are closed to cylinder wall, the flow coefficient and swirl intensity are increased. Also we realized that there is a trade-off that the increase of swirl ratio decreases mean flow coefficient and increases the Gulf factor. And the optimum parameters to meet performance and emission through engine test are as follows; the swirl ratio 2.43, injection timing BTDC 13oCA and compression ratio 15.5.