• 한국분무공학회지
• /
• 제11권2호
• /
• pp.69-74
• /
• 2006

This is an experimental study on the performance characteristics and combustion characteristics of common-rail type diesel engine by using ultrasonic energy. It is carried out engine performance by engine dynamometer test and combustion characteristics using ultrasonically irradiated diesel fuel in comparison with using conventional diesel fuel. In analyzing the experiments of these results generally, these are obtained as follows. There is an affirmative effect on the side of the improvement of power and the reduction of smoke by applying the ultrasonically irradiated diesel fuel to the common rail engine. But there is less effect on the side of improvement of BSFC.

• 동력기계공학회지
• /
• 제15권5호
• /
• pp.10-15
• /
• 2011

This paper describes the engine performance and combustion characteristics of a CRDI diesel engine, operated by electronically controlled diesel fuel injector with variable injection timing. This experiment focused on fuel injection timing and pressure about combustion characteristics of CRDI diesel engine. EGR was excepted because it would be furtherly analyzed with additional experiments. The experiment was conducted under the circumstance of engine torque for 4, 8, 12 and 16 kgf-m and fuel injection timing for $15^{\circ}$, $10^{\circ}$ and $5^{\circ}$ BTDC, at the engine speed of 1100, 1400, 1700 and 2000 rpm. Fuel injection was controlled to retard or advance initiation of the injection event by electronically controlled fuel injection unit injector on the personal computer. When fuel was injected into the cylinders of a CRDI diesel engine it would go through ignition delay before starting of combustion. Therefore, fuel injection timing of CRDI diesel engine had a significant effect upon performance and combustion characteristics. Depending on the injection timing the fuel consumption rate following the rotational speed and torque was 3~78 g/psh (1.7~30.6%). The range of fuel injection timing that resulted in low fuel consumption overall was BTDC 15-10 degrees.

• 한국산학기술학회논문지
• /
• 제15권5호
• /
• pp.2573-2578
• /
• 2014

본 연구는 4실린더 커먼레일 디젤 기관에서 바이오 디젤 혼합 연료를 사용하여 예비 분사시기와 EGR율을 변화시켰을 때 연소 압력과 배기 특성에 미치는 영향을 조사하기 위하여 실험을 수행하였다. 예비 분사 시기와 EGR율은 디젤 기관의 연소 및 배기 배출 특성에 큰 영향을 미친다. 본 연구에서는 일반적으로 많이 사용되고 있는 기관 회전 속도 2,000rpm에서 바이오 디젤 혼합율 20%의 연료를 사용하여 예비 분사 시기와 EGR율에 다양하게 변화를 주어 실험을 하였다. 실험결과, 도시 평균 유효 압력은 예비 분사 시기가 상사점전 BTDC $10^{\circ}$에서 가장 높았으며, 연소 압력과 열 발생율은 동일 예비 분사 시기에서 EGR율에 비례하여 감소하였다. NOx배 출량은 예비 분사시기에 관계없이 EGR율이 증가할수록 큰 폭으로 감소하였으며, 매연(Soot)은 예비 분사 시기 BTDC $20^{\circ}$에서 가장 적게 배출되었다.

• Journal of Mechanical Science and Technology
• /
• 제18권9호
• /
• pp.1640-1647
• /
• 2004

This study was to investigate the effects of water induction through the air intake system on the characteristics of combustion and exhaust emissions in an IDI diesel engine. The fuel injection timing was also controlled to investigate a method for the simultaneous reduction of smoke and NOx when water was injected into the combustion chamber. The formation of NOx was significantly suppressed by decreasing the gas peak temperature during the initial combustion process because the water played a role as a heat sink during evaporating in the combustion chamber, while the smoke was slightly increased with increased water amount. Also, NOx emission was significantly decreased with increase in water amount. A simultaneous reduction in smoke and NOx emissions was obtained when water was injected into the combustion chamber by retarding more 2$^{\circ}C$A of the fuel injection timing than without water injection.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
• /
• pp.33-38
• /
• 2002

An optical single cylinder diesel engine equipped with a common-rail injection system has been built to investigate diesel combustion and emission characteristics. Three optical widows (piston crown quartz for bottom view of the cylinder, upper piston quartz for allowing laser sheet and liner quartz for side view) have been placed in the optical engine to visualize spray characteristics and combustion process inside the cylinder. Before doing further research using various optical diagnostics with the optical engine, fundamental combustion experiments and flame visualization incorporating a high speed motion analyser have been carried out with a wide range of engine operating conditions.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2000년도 추계학술대회논문집B
• /
• pp.162-167
• /
• 2000

Soot formation and oxidation is closely related to the combustion phenomena inside a diesel engine. Laser-based diagnostics provide a means for improving our understanding of diesel combustion, because they have highly temporal and spatial ability. To understand the soot behavior we did preliminary study by taking flame luminosity photographs and 2-D imaging soot distribution using Laser Elastic Scattering(LIS) and Laser-Induced Incandescence(LII). From the data we found that soot concentration was high in the bowl and disappeared from the central region in the late combustion stage.

• 한국자동차공학회논문집
• /
• 제2권6호
• /
• pp.76-86
• /
• 1994

Combustion of diesel engine depends on the mixing of air and evaporating fuel during ignition delay greatly. Variation of air-fuel mixing rate and ignition delay for engine operating condition causes difference of combustion, performance and exhaust emissions. This study is investigated in a turbocharged diesel engine of IDI swirl chamber type. In the results, As injection timing is advanced until $12.6^{\circ}$ BTC, ignition delay decreases. NOx concentration and smoke level in exhaust gas increases for advanced injection timing Ignition delay, combustion period, pressure rise rate and exhaust gas temperature are increased with increasing engine speed. And ignition delay at high load is more decreased than that at low load. Ignition delay and combustion period are decreased with increasing intake pressure. Power increases, temperature and CO, NOx concentration in exhaust gas decreases as intake pressure increases. With increasing load, ignition delay is decreased and combustion period, motoring pressure are increased.

• 한국자동차공학회논문집
• /
• 제12권1호
• /
• pp.10-16
• /
• 2004

The Homogeneous Charge Compression Ignition (HCCI) engine has advantage for reducing the NOx and P.M. simultaneously. Therefore, HCCI engine is receiving attention as a low emission diesel engine concept. This study was carried out to investigate the characteristics of combustion and exhaust emission for operating conditions in a direct injection type of HCCI engines such as supercharged and naturally aspirated using diesel fuel and additive. From the experimental result, we found that cool flame was always appeared and also it was difficult to control combustion characteristics by changing the injection timing in HCCI. In addition, at the lean air-fuel ratio and high speed range, it was observed that charging air pressure, additive or increasing intake air temperature is effective to increase combustion performance and reduce exhaust emission. We concluded that chemical reaction by the increasing intake air temperature or additive without physical improvement has limitation for reduction of exhaust emission.

• 대한기계학회논문집B
• /
• 제34권10호
• /
• pp.941-946
• /
• 2010

1.7L 커먼레일 직접분사 디젤엔진에 대하여 바이오 디젤 연료가 conventional 연소(PM-NOx 트레이드오프 존재)와 저온 연소(low temperature combustion, LTC)에서 배기가스 배출에 미치는 영향을 분석하였다. LTC 연소는 conventional 연소 대비 다량의 EGR 과 연료분사 조건 최적화를 통하여 이루어졌다. 실험에 사용한 두 가지 연료는 초저유황 디젤연료(ultra low sulfur diesel fuel, ULSD), ULSD 에 대두유를 20%(vol. base)혼합한 바이오 디젤 연료(B20)이다. 사용된 연료에 관계없이 LTC 연소를 통하여 conventional 연소 대비 PM 및 NOx 의 동시 저감이 가능하였다. 동일한 엔진작동 조건에 대하여 conventional 연소의 경우 B20 는 ULSD 보다 PM은 적게 배출되나, NOx 는 많이 배출되었다. LTC 연소의 경우 B20 는 ULSD 보다 PM 및 NOx 생성이 많았다.

• 한국분무공학회지
• /
• 제17권4호
• /
• pp.178-184
• /
• 2012

The aim of this study was to compare the spray characteristics of a typical fuel (100% diesel, DME) and diesel-DME blended fuel in a constant volume combustion chamber (CVCC). The typical fuel (100% diesel, DME) and diesel-DME blended fuel spray characteristics were investigated at various ambient pressures (pressurized nitrogen) and fuel injection pressures using a common rail fuel injection system when the fuel mixture ratio was varied. The fuel injection quantity and spray characteristics were measured including spray shape, penetration length, and spray angle. Common types of injectors were used.