• 한국자동차공학회논문집
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• 제3권4호
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• pp.12-18
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• 1995

To improve the performance of diesel automobile engine, we designed new fuel supply system named ultrasonic fuel supply system. The performance test of diesel automobile engine carried out to examine possibility of practical use of ultrasonic fuel supply system to test engine. This paper deals with the comparative results of performance test of diesel automobile engine in terms of smoke, HC, SFC, PS, thermal, efficiency, torque. Following are obtained result. 1) In naturally aspirated diesel engine, when we use ultrasonic fuel supply system output, fuel consumptions are improved and exhaust gas reduced significantly. 2) In turbo-charging diesel engine both using of ultrasonic fuel supply system and using of conventional injector, engine performance and exhaust gas temperature are almost constant. 3) In turbo-charging diesel engine, when we use ultrasonic fuel supply system, NOx are emitted approximately 3.5% higher than total average. 4) In turbo-charging diesel engine, when we use ultrasonic fuel supply system, smoke and CO are 17% and 11.8% improved respectively.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.171-176
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• 2006

연료 과농 가스발생기에 대한 실험적 연구가 수행되었다. 연소 성능에 주요한 영향을 미치는 분사기 헤드에는 1.5의 리세스 수를 갖는 내부 혼합형 이중 스월 분사기 37개가 배치되었다. 본 논문에서는 연소실 길이, 직경, 그리고 교반링 등의 연소실 설계 변경에 따른 실물형 가스발생기의 연소 안정성 특성에 대하여 살펴보았다. 연소시험 결과 공진 주파수가 고주파 영역에서 생성됨에 따라 동압의 세기는 전반적으로 감소하였으나, 연소 불안정을 완전히 억제시키지는 못하는 것으로 나타났다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.806-811
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• 2001

Since the characteristics of combustion and pollutant in Diesel engines were mainly effected by the characteristics of in-cylinder gas flow and fuel spray, an understanding of those was essential to the design of the D.I. Diesel engines. The improvement of volumetric efficiency of air charging into combustion chamber is a primary requirement to obtain better mean effective pressure of an engine. Since parameters such as the air resistances in intake and exhaust flow passages, valve lift and valve shape influence greatly to the volumetric efficiency, it is very important to investigate the flow characteristics of intake and exhaust port which develops air motion in the combustion chamber. In this study, two approach methods were used for design intake and exhaust port; experiment and computation which were made by using steady flow test rig and commercial CFD code. This paper presents the results of an experimental and analytical investigation of steady flow through the prototype cylinder head ports and valves of the HHI's H21/32 HIMSEN Engine.

• 한국항공우주학회지
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• 제44권4호
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• pp.343-351
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• 2016

초임계 환경에서 작동하는 와류형 분사기의 극저온 질소 분무특성을 3차원 LES 수치기법을 적용하여 연구하였다. 초임계 상태에서 질소의 상태량을 예측하기 위해 초임계 상태에서 적용되는 상태방정식들을 비교하여 가장 정확한 SRK 상태방정식을 적용하였다. 또한 점성계수와 열 전도도는 Chung이 제안한 고압상태 혼합물에 대한 방정식을 적용하였으며 확산계수는 Fuller의 이론에 Takahashi가 제안한 방정식을 적용하였다. 질소로 채워진 50bar의 챔버에 5bar의 차압으로 질소를 분무하여 수치해석을 수행하였다. FFT를 이용한 주파수 분석을 통해 대수적 Smagorinsky와 동적 Smagorinsky를 실험결과와 비교하여 동적모델이 더 적합함을 판단하였다. 분사기 내부의 액막, 가스층에서 나타나는 불안정성과 분사기 외부에서 나타나는 불안정성의 원인에 대해 분석하고, 불안정성이 분사기 내부로 전파되는 현상에 대해 조사하였다. 또한 분무각에 대하여 실험 결과와 비교 검증하였다.

• 대한기계학회논문집
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• 제7권3호
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• pp.257-262
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• 1983

The performance of a direct-injection type diesel engine often depends on the shape of combustion chamber, strength of swirl or squish, the number of nozzle holes, etc. This is of course because the process of combustion in the cylinder was affected by the mixture formation process. In this paper, the relation betweeen the flame progress and the performance of engine was clarified by changing variously the combustion process in cylinder with a special method, and thus the measures for improving the combustion were indirectly examined. Namely it was investigated what effect the flame progress in cylinder, which was varied with the locality of the lean premixture injected by the auxiliary injection method using an auxiliary injection nozzle in advance at the place where main spray was injected later, has on the engine output, the exhaust smoke density and the NO concentration in exhaust gas.

• 한국자동차공학회논문집
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• 제9권4호
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• pp.34-43
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• 2001

Analysis and control of intake charge motion such as swirl and tumble are very important to improve the performance of gasoline engines. In this paper, single frame double exposure PTV(particle tracking velocimetry) is used to investigate intake flow characteristic in a steady flow test rig of gasoline engine with 2-valve and pent-roof combustion chamber. To validate this PTV method, we confirmed reliability of this PTV method using chopper, and coaxial burner experiments. The velocity Held of intake flow is measured with the intake valve lift variation. It is shown that maximum flow velocity is increased and tumble flow become stronger than inverse tumble flow as valve lift increase.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.19-26
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• 2002

The objective of this study is to examine a DI(Direct Injection) gasoline spray development process under different ambient pressures using PIV(Particle Image Velocimetry). fuel spray experiments were performed within a constant volume chamber. The spray structure, velocity maps, velocity and vorticity contours were obtained to investigate its spray characteristics. It was found that higher ambient pressure has a significant effect on radial growth of the spray. The position which has a maximum velocity moved from the spray edge to the spray center as ambient pressure was increased. Higher ambient pressure moved a maximum vorticity position upward of the spray.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.25-31
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• 2004

In order to prepare for the large power diesel vehicle, the current trend of advanced nations is to shift from the aluminum alloy piston to the steel piston. In this research, a steel forging piston which replaces the aluminum alloy piston is developed to improve the power performance of the diesel engine. The three dimensional flow and combustion analysis of the target engine is conducted. Using the result of the analysis, the piston is optimized, and a prototype of the articulated steel forging piston is built. The reliability of the piston has been evaluated through durability test using a Hydropuls Test Machine for 300,000 km.

• 한국농공학회지
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• 제18권4호
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• pp.4259-4264
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• 1976

This paper, is about the test on the operating performance of diesel engine by using of soybean oil which farmers could supply in their farm yard. The diesel engine used is a swirl-chamber type, four stroke cycle with single cylinder, air cooling and its rated horse power is 2 PS per 1300 rpm. Several results obtained are as follows; 1. The starting performance of diesel engine with soybean oil is almost the same as that with light oil. 2. The variation of engine speed according to various engine load is small when soybean oil is used compared with light oil. It is considered that soybean oil is desirable for the purpose of industerial power machine fuel. 3. The specific fuel consumption increases approximately 10 percent high in the condition of rated horse power and maximum horse power and shows less or same during the load test in low velocity, when soybean oil is used 4. Though the brake thermal efficiency in the condition of rated horse power and maximum horse power is inclined to decrease when soybean oil is used compared during the load test in low velocityt shows good inclination.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2015년도 제51회 KOSCO SYMPOSIUM 초록집
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• pp.107-108
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• 2015

The acoustic optimization of a swirl coaxial jet injector mounted upstream a combustion chamber is investigated to tackle combustion instabilities. The least damped modes are extracted with the help of the dynamic mode decomposition (DMD). The sensitivity of the heat release perturbation to the velocity perturbation for the second longitudinal mode is investigated by combining the Crocco's equation and the inhomogeneous wave equation and computing the flame transfer function (FTF). DMD and FTF results agree in terms of the optimized injector length.