• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.283-284
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• 2014

• Journal of Energy Engineering
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• v.25 no.1
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• pp.122-130
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• 2016

This study is a numerical study using commercial simulation program GT-Power on 1.5MW diesel engine for power generation. Performance comparison has done for diesel operation with dual fuel operation for different engine load(50%, 75%, 100%) using the target engine model with additional gas injection system. Effect of using Hi-sene, which is actually being used in island area, instead of diesel was also studied. As a result, under 60% natural gas with diesel condition, BSFC was increased by 32% without modifying system. There was almost no change for natural gas/Hi-sene condition compared with natural gas/diesel condition. Decrease of burned fuel fraction was the main reason of these phenomena. After optimizing system, BSFC was improved by 2%.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.10
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• pp.941-946
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• 2010

This study aims to investigate the effects of soybean biodiesel fuel on exhaust emissions with regards to two combustion modes: conventional combustion(existence of PM-NOx trade-off behavior) and low temperature combustion(LTC) in a 1.7 L common rail direct injection diesel engine. As compared to conventional combustion, LTC was achieved by adopting a heavier exhaust gas recirculation and strategic injection parameter optimization. Two sets of fuels, i.e. ultra low sulfur diesel(ULSD) and 20% volumetric blends of soybean biodiesel with ULSD(B20) were used. Regardless of the fuel type, in LTC the simultaneous reduction of PM and NOx was observed and both levels were significantly lower than in case of conventional combustion. Under the given engine operating condition in the case of conventional combustion, B20 produced less PM and more NOx than ULSD. In the case of LTC combustion, B20 produced more PM and NOx than ULSD.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.11
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• pp.1065-1072
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• 2012

Due to its oxygen (O) content, biodiesel (BD) is advantageous in that it lowers PM emissions in CI engines. Therefore, BD is considered one of the best candidates for low temperature combustion (LTC) operation because its use can extend the regime for simultaneous reduction of PM and $NO_x$. Thus, in this study, LTC operation was realized using BD and diesel with a 5~7% $O_2$ fraction. Engine test results show that the use of BD increased the efficiency and reduced emissions such as PM, THC, and CO; furthermore, IMEP reduced by 10~12% owing to the lower LHV of the fuel. In particular, smoke was suppressed by up to 90% because O atoms in the BD enhanced the soot oxidation reaction. To compensate the IMEP loss, turbocharging (TC) was then tested, and the results showed that the power output increased and PM was reduced further. Moreover, TC in BD engine operation allowed a similar level of reduction in both $NO_x$ and PM at 11~12% $O_2$ fraction, suggesting that there is a potential to widen the operating range by the combination of TC and BD.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.44-49
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• 2016

This paper presents characteristics of diesel combustion and emissions according to adoption of various combustion chamber geometry. In order to suggest suitable combustion chamber geometry of the common rail diesel engine for electric generative use, 5 type of geometry chamber was found performance for combustion chamber to respond fuel efficiency. Combustion chamber geometry affects combustion characteristics due to change target area of spray in the combustion chamber and the main factor was the bowl aspect ratio of combustion chamber. Using the results of simulation, the effects of the variable combustion chamber can be improved the fuel efficiency for electric generation.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.9
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• pp.1081-1086
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• 2014

An experimental study was performed in order to compare with the case of using pure diesel the characteristics of combustion pressure and exhaust emissions when the engine speed was changed in a CRDI 4-cylinder diesel engine using biodiesel( Canola oil) blended and pure diesel fuel. As a results, the combustion pressure was decreased with increasing biodiesel blended rate when engine speed was 1,000, 1,500, 2000(rpm). but the combustion pressure of the engine speed 2,500rpm was increased with increasing biodiesel blended rate. The emission results show, that CO was decreased with increasing biodiesel blended rate and engine speed. The emission of $CO_2$, NOx, were increased with increasing biodiesel blended rate and engine speed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.945-951
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• 2012

A water emulsion fuel can be used to reduce soot and NOx emissions simultaneously because it has a lower combustion temperature and better fuel atomization owing to the evaporative latent heat and microexplosion of water. Moreover, it can be used without making special modifications to conventional diesel engines. Therefore, this fuel has attracted considerable research attention. In addition, lower-grade fuels are being considered for use in conventional engines because of an increase in oil prices. In this study, we investigated the combustion and exhaust characteristics of MDO (marine diesel oil), which has a lower grade than common diesel oil, and ME (MDO water emulsion) under various test conditions in an automotive diesel engine.

• Journal of Power System Engineering
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• v.15 no.3
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• pp.5-11
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• 2011

디젤기관의 경우는 종래부터 직분식이 주류를 이루었고, 근래에는 분사압력의 고압화가 진행중이다. 분사압력의 고압화에 의해 연소효율의 향상 및 배출가스중의 입자상물질(PM:Particulate Matter)의 저감을 유도하고 있으나, 연소가스의 고온화로 인해 질소산화물(NOx:Nitrogen Oxides)은 증가한다. 따라서, 분사기간의 지연(Retard)이나 파일럿분사(Pilot injection)등의 혼합기제어에 의해 질소산화물의 저감을 꾀하고 있다. 이와 같이 디젤기관에 있어서도 혼합기 형성의 최적화에 의한 연소제어를 시도하는 수법이 중시되고 있고, 이를 위해서는 디젤분무 구조에 기초한 혼합기의 형성기구에 대한 규명이 매우 중요하다. 그러므로 본 연구에서는 보다 고도의 혼합기형성 제어를 위한 기초연구로서 고온 고압장에서의 증발디젤자유분무구조를 해석하였으며, 계측영역은 연료와 주위기체와의 혼합이 활발히 진행되는 분무의 하류영역으로 설정하고, 입자화상속도측정법(particle Image Velocimetry:PIV)을 이용한 분무의 유동해석을 기초로 증발 디젤분무의 구조 해석을 행하였다. 실험조건으로서 분사압력을 72MPa, 112MPa로 각각 변화시켰다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.745-745
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• 2012

원자력발전소에서 비상디젤발전기는 노심의 안전성을 지키는 매우 중요한 역할을 담당하고 있다. 이를 위해 디젤발전기는 신뢰성능 높게 유지하도록 규제요건이 마련되어 있다. 디젤발전기의 엔진 상태를 주기적으로 감시하고 평가하기 위해서는 엔진 상태 신호 분석 기술이 필요하다. 엔진 상태 신호 분석에는 연소분석과 진동 및 초음파 측정 및 분석기술이 중요한 비중을 차지한다. 연소 분석은 디젤 엔진의 개별 실린더에 대한 연소 성능에 대한 정보를 제공한다. 진동 및 초음파 분석은 이벤트 타이밍과 기계적 상태에 대한 정보를 알려준다. 이들 신호는 정상적인 부하로 운전하는 디젤엔진의 가동에 영향을 미치지 않고 수집할 수 있다. 엔진 상태 신호 분석을 이용하는 주요 동기는 전통적으로 장비 제작자의 권고에 따라 수행되는 분해-검사 유지 보수 프로그램을 일부 대체하고 예측정비를 통해 신뢰도를 유지하기 위함이다. 상태 진단정비는 엔진 상태 신호분석을 주로 이용하여 엔진의 신뢰도와 이용률을 증가시킬 수 있다. 본 논문에서는 국내외서 경험한 엔진상태신호 측정 및 분석 사례를 기술하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3383-3388
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• 2014

An experimental study was performed to compare the characteristics of the combustion pressure and exhaust emissions in the case of using pure diesel when the EGR rate was changed in a CRDI 4-cylinder diesel engine with those using biodiesel blended and pure diesel fuel. In this study, the EGR rate variation were conducted at an engine speed of 2000rpm with fuel with a biodiesel blended rate of 20%. The combustion pressure of the biodiesel blended rate 20% and pure diesel fuels decreased with increasing EGR rate. The IMEP of biodiesel was higher than that of ULSD (Ultra low sulfur diesel). The emission results showed that the NOx emission of biodiesel blended fuel with increasing EGR rate was higher than that of ULSD. In addition, the NOx emission of biodiesel blended and diesel fuel decreased with increasing EGR rate. The CO and soot, $CO_2$ emissions increased with increasing EGR rate, and the CO and soot emissions from the biodiesel blended fuel were lower than that of ULSD but the $CO_2$ emissions were higher.