L.P SCR의 촉매 반응을 위해 선박의 발전기용 4행정 디젤엔진의 배기가스 온도를 높게 설계 할 수밖에 없었다. 본 연구의 목적은 밸브개폐시기와 연료분사시기를 조정을 통한 배기가스의 온도 감소가 L.P SCR의 운전조건을 만족시키고 고온으로 인한 발전기 엔진의 사고를 예방하기 위함이었다. 배기가스 온도를 하강시키기 위해 캠샤프트의 각도를 조정하고 연료분사펌프의 Shim을 추가하였다. 그 결과 최대폭발압력은 12.8 bar 증가하였고 터보차저 출구온도 평균값은 13.3 ℃ 하강하였다. 터보차저 출구에서 SCR 입구까지의 열손실을 감안하더라도 L.P SCR 운전조건인 SCR 챔버 입구 온도인 290 ℃를 만족하였다. 배기가스 온도 하강을 통해 디젤발전기의 안전운전이 가능하게 한 연구였다.

These days, our environmental pollution has been greatly threatened by various exhaust emissions from diesel engines for transportation, and there is a tendency that regulations on this are very strengthened. In this study, when biodiesel and water-cooled EGR are simultaneously applied to common rail diesel engines, which occupy most of passenger diesel engines, the characteristics of exhaust smoke and NOx were investigated. As a result of this experiment, as a result of applying less than 10% EGR to 5% biodiesel mixed fuel, it was found that smoke and NOx emissions can be simultaneously reduced.

Roto cap is usually used to diesel engine, especially, big-sized diesel engine such as ship, power plant and so on. Intake and exhaust valves are essential parts of diesel engine and thus roto cap is one of the most important parts of intake and exhaust valves. Roto cap consists of body, disc spring, spring & steel ball, retainer and stop ring. In this study, the body and disc spring in parts of roto cap were simulated using static structural analysis. The purpose of this study is to achieve the data for designing and improving the roto cap. As the results, the body of roto cap showed safety factor of 6.3 in even 2 times of 1370N(target load) and the disc spring showed safety factor of 4.9 in 2370N load.

In recent years, our reality is facing a serious risk of air pollution from transport vehicles. In particular, various exhaust emissions from diesel engines are pointed out as a serious cause of environmental pollution. This study attempted to study the potential of biodiesel as an alternative energy for CRDI diesel engines. When biodiesel 30% was applied, the smoke emission was reduced by 40% at 4000rpm compared to diesel. On the other hand, there was no significant difference in output, torque, and energy consumption. However, NOx emissions tended to increase compared to diesel. The applicability of biodiesel to CRDI diesel engines has been demonstrated for the characteristics of output and smoke emissions.

본 연구에서는 선박용 디젤 엔진에서 발생되는 크랭크케이스 수트(soot)의 재활용 가능성을 검토하기 위하여, 수트를 배기관에서 발생하는 수트와 크랭크케이스에서 발생한 수트로 분류하고, 열처리에 따른 수트의 구조적 특성을 분석하였다. 열처리는 아르곤 가스 분위기에서 2,000℃와 2,700℃로 열처리를 수행하였고, 샘플의 구조적 특성 분석을 위해 라만분광법(Raman spectroscopy)과 고분해능 전자현 미경(HRTEM)을 활용하였다. 또한, 취득한 HRTEM 이미지를 정량적으로 분석하기 위해 디지털 이미지 처리(Digital Image Processing) 기법을 활용하였다. 라만 분석 결과, 배기 수트와 2,700℃로 열처리한 수트에서 상대적으로 높은 G/D ratio가 나타났다. HRTEM 이미지에서는 두 수트 모두 유사한 형태의 흑연화된 나노 구조를 확인할 수 있었으나, 수트의 종류와 열처리 온도차에 따른 흑연화 정도의 차이를 정량 적으로 도출할 수 없는 한계가 있었다. 이에 Digital Image Processing을 통해 HRTEM 이미지의 fringe의 길이와 곡률을 정량적으로 분석하였으며, 라만 분석과 일치하는 결과를 도출할 수 있었다. 이는 배기 수트가 크랭크케이스 수트에 비해 더 흑연화 된 구조를 가지는 것을 의미하며, 더 높은 온도에서 열처리 할 경우 흑연의 구조로 더 잘 발달함을 의미한다. 본 연구의 결과로 크랭크케이스 수트 역시 배기 수트 와 마찬가지로 흑연계 재료로 재활용이 가능함을 확인하였다.

In this paper, we compare and analyze the injector defects of P-ENG and S-ENG with normal injectors by measuring current waveforms, voltage waveforms, exhaust gases and driving fuel economy. In the case of FTS failure, the S-ENG reduced the overall injection time by 3.7% and the main injection by 3.5% compared to the normal engines. In the case of AFS failure, the overall injection time increased by 45.7% and the main injection time increased by 24.1% compared to the normal engine. The rest data showed that fuel economy of S-ENG had 25.9% higher than P-ENG, NOX had 162.5% higher than that of P-ENG, and CO2 of S-ENG had 26.7% lower than P-ENG.

In this study, we compared of control characteristics at two-stroke marine diesel engine by MAN B&W. It was found that MC and ME type of engine largely divide fuel injection & exhaust valve actuator by cam-shaft controlled and electro-hydraulic controlled. Computer based type of engine ME-B type is only operated exhaust valve by driving camshaft, the fuel injection system is fuel oil booster and ELFI valve by Electro-hydraulic. ME-C type is composed of a multi-way valve or FIVA valve. Therefore fuel injection system and exhaust valve system is operated by Electro-hydraulic. ME type engine was shown that the optimization of the combustion process can be achieved for any load on the engine by Electro-hydraulic control system according to the computer based.

In this paper, the injectors with normal quantity, over quantity of +10%, under quantities of -10% and –30%, were mounted on S-ENG and P-ENG in order to measure the voltage energy, current energy and power supplied to the injectors and the fuel economy under several speed of rpm conditions. The voltage and current energy of S-ENG was greater than P-ENG, and the power of S-ENG was measured and analyzed 4.8 times higher than that of P-ENG at all injectors, and the tendency of carbon dioxide emissions calculated from fuel efficiency measurement results was not significantly affected by the type of injectors, but P-ENG was measured to be slightly affected by the type of injectors. It is assumed that the model year and mileage of the test vehicle affects this tendency.

In the past, the U.S. NRC(Nuclear Regulatory Commission) strictly required testing of the EDG for NPP through Reg.Guide 1.108 Rev 1. However, these test requirements acted as a deterioration and wear factor for diesel engines, and are now applying Reg.Guide 1.9 Rev 3, which relaxed regulatory requirements and improved performance monitoring. After applying the new regulatory guidelines in this study, the EDG analyzed the performance of the combustion chamber. As a result, there were no signs of deterioration or decreased performance of the current EDG. This is due to slow start, short operation time, the use of high quality fuel oil and proper maintenance. On the other hand, if the performance is proven, it is judged that proper period extension of cylinder maintenance is possible.

선박용 디젤엔진의 NOx 환원제로 액체 우레아를 사용하는 SCR 기술이 널리 사용되고 있다. 하지만 액체 우레아 대신에 고체 상의 암모늄 카바메이트를 NOx 환원제로 사용하면 저온 NOx 저감율 및 암모니아 저장용량 측면 등에서 다양한 장점이 있다. 이에 따라 본 연구에서는 암모늄 카바메이트를 EA, FTIR, XRD 방법으로 분석하여 순도를 관리하는 방법을 제시하고자 하였으며, 다양한 온도와 압력 조건에 암모늄 카바메이트가 노출되었을 때의 물질 변화 특성을 고찰하고자 하였다. 본 연구를 통하여 암모늄 카바메이트의 순도를 EA 분석을 통해 효과적으로 관리 할 수 있음을 알 수 있었으며, 선박용 디젤엔진의 SCR 시스템에 적용될 것으로 예상되는 열분해 온도 조건에서 가열과 냉각을 반복한 암모늄 카바메이트에 대한 FTIR 분석결과, 물질 특성은 변화하지 않는 것을 확인하였다. 또한, 대기 중에 장기간 노출된 암모늄 카바메이트는 암모늄 카보네이트로 물질 변화함을 알 수 있었다.

This work reports the syntheses of an inexpensive and efficient asphalt-derived mesoporous carbon (AdMC) as an adsorbent. The adsorbent was activated with potassium hydroxide to increase its surface area and then characterized by SEM–EDS, FT-IR, and BET. The adsorption properties of AdMC were evaluated for the adsorptive removal of eleven Poly Aromatic Hydrocarbons (PAHs) and diesel from water samples. The prepared AdMC showed very high surface areas and high micropore volumes equal to 2316 m2/g and 1.2 cm3/g, respectively. Various experimental conditions influencing the adsorption capacity of eleven PAHs and diesel were investigated. At high concentrations, PAHs and diesel solubility in water is very low. Hence, samples were emulsified with a surfactant, and then maximum adsorption capacity was investigated. Adsorption profile of individual PAHs was examined using gas chromatography/mass spectrometry analysis followed by liquid–liquid extraction. Total hydrocarbon removal was studied using a total organic analyzer. Asphalt-derived mesoporous sorbent showed an extreme ability to remove PAHs and diesel (average adsorption capacity of 166 mg/g for individual PAHs and diesel (maximum capacity of 1600 mg/g). The experimental results fitted the Langmuir model with a correlation efficiency of 0.9853. The results obtained for both adsorbents also matched to pseudo-second-order kinetics, suggesting that the adsorption of PAHs and diesel is chemical, monolayer, and homogeneous process.

In order to design a diesel engine system and predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. A gas flow analysis in three-dimensional (3D) format needs a high-resolution workstation and enormous time for analysis. Therefore, the method of characteristics (MOC) was used for a gas flow analysis with a fast calculation time and a low-resolution workstation. An experiment was conducted on a single cylinder diesel engine to measure pressure in cylinder, intake pipe and exhaust pipe. The one-dimensional (1D) gas flow was analyzed under the same conditions as the experiment. The engine speed, valve timing and compression ratio were the same conditions and the intake pressure was inputted as the experimental results. Bent pipe such as an exhaust port that cannot be realized in 1D was omitted. As results of validation, the cylinder pressure showed accuracy, but the exhaust pipe pressure exhibited inaccuracy. This is considered as an error caused by the failure to implement a bent pipe such as an exhaust port. When analyzed in 3D, calculation time required 61 hours more based on a model of this study. In the future, we intend to implement a bent pipe that cannot be realized in 1D using 3D and prepare a method to supplement reliability by using 1D-3D coupling.

In this study, we investigated the effects of diesel-palm oil biodiesel-ethanol blends on combustion and emission characteristics in a 4-cylinder common rail direct injection (CRDI) diesel engine at low idling operations. The engine speed and engine load was 750 rpm and 40 Nm, while the main and pilot injection timing was respectively fixed at 2 °CA before top dead center (BTDC) and 20 °CA BTDC. The experimental results showed that the cylinder pressure increased with the increasing of palm oil biodiesel ratio from 20% to 100%. In addition, the peak value of cylinder pressure increased by 4.35% compared with pure diesel fuel when 5 vol.% ethanol oil added to diesel oil. Because the palm oil biodiesel and ethanol are the oxygenated fuel, the oxygen content played an important role in improving combustion. Based on the high oxygen content of biodiesel and ethanol, their mixing with diesel fuel effectively reduced PM emissions but increased NOx slightly, while CO and HC had no significant changes.

본 연구에서는 IMO의 향후 예상 규제 물질 중 하나인 수트를 선박용 엔진을 대상으로는 최초로 배기 수트와 엔진 수트로 구분 하여 구조적 특성의 비교 분석을 시도하였다. 그리고 최근 발표되고 있는 배기 수트 재활용 연구의 연장선상에서 엔진 수트의 재활용 가 능성 여부를 확인하기 위하여 2,000℃로 열처리를 시행하였고, 열처리 전·후의 수트를 고분해능 전자현미경과 라만분광법을 통해 분석하 였다. 전자 현미경을 통한 분석 결과, 배기 수트와 엔진 수트는 유사한 형태의 나노 구조를 가지고 있으나, 배기 수트는 구형의 1차 입자 가 체인형 결합구조를 가지고 있었고, 엔진 수트는 배기 수트에 비해 무정형한 구조가 확인되었다. 라만분광법 분석 결과, 배기 수트와 엔 진 수트 모두 D peak(1,350 cm-1)와 G peak(1,580 ~ 1,600 cm-1)가 확인되었다. 다만, G/D ratio는 엔진 수트에 비해 배기 수트가 상대적으로 높게 나타나며, 이는 배기 수트가 더 흑연화 된 구조를 나타냄을 의미한다. 열처리 후의 분석 결과, 엔진 수트도 배기 수트와 유사하게 흑연화 가 문제없이 진행됨을 확인하였고, 이를 통해 선박용 디젤엔진에서 발생하는 배기 수트와 엔진 수트 모두 흑연재료로 재활용이 가능함을 확인하였다.

In this study, the effect of various pilot injection timings on combustion and emission characteristics were investigated in a common-rail direct injection (CRDI) diesle engine fueled with diesel-ethanol blends. The engine speed and engine load were controlled at constant 1500rpm and 70Nm, respectively. The tested fuels were DE0 (pure diesel fuel), DE5 (5 vol.% ethanol blended with 95 vol.% diesel oil), DE10 (10 vol.% ethanol blended with 90 vol.% diesel oil) and DE15 (15 vol.% ethanol blended with 85 vol.% diesel oil). The main injection timing was fixed at 0°CA TDC (top dead center), while various pilot injection timings including 25°CA BTDC (before top dead center), 20°CA BTDC and 10°CA BTDC were selected as the experimental variable. The experimental results showed that various pilot injection timings had little effect on the peak value of cylinder pressure, but had great influence on the start of combustion. The peak value of heat release rate (HHR) increased with the increase of ethanol content. However, the peak value of HRR reduced as the pilot injection is delayed. The diesel fuel containing 10% ethanol had a highest peak value of combustion pressure compared with the others, while the pilot injection timing occurred at 25°CA BTDC. On the other hand, the exhaust emissions of DE10 was also the lowest compared with the others. In addition, with the increase of ethanol content in diesel the PM and NOx emissions reduced.

미세먼지발생 문제는 커다란 사회적 문제로 대두되고 있다. 선박에서는 주 추진 동력원으로 디젤엔진을 주로 사용하고 있다. 본 연구에서는 디젤엔진에서 발생하는 미세먼지로 알려진 입자상 물질을 줄이기 위해서 디젤엔진의 후처리시스템으로 사용 중인 DPF(디 젤미립자 필터, Diesel particulate filter)를 소개하고자 한다. DPF의 소재로는 Cordierite와 SiC (Silicon carbide)의 두 가지가 사용되고 있다. 본 논문에서는 SiC DPF에 사용되는 접합제의 물성 향상을 위해서 기존 접합제로 사용된 SiC 계열의 물질 대신 코디얼라이트를 사용하여 열 팽창계수 변화를 통한 고온 변형에 대한 열 내구성을 평가하였으며, 접합제와 Segment 사이의 결합을 결정짓는 바탕제에 주성분인 실리카 졸의 pH 변화에 따른 물성 변화를 확인하였다. 이를 기반으로 실리카 졸의 반응성을 높이기 위해 Siline계 커플링제를 첨가하거나 SiC를 일부 첨가함으로써 접합제의 물성 변화의 영향에 대해서 실험을 통하여 확인하였다.

본 논문에서는 선박용 디젤엔진의 미세먼지저감 장치에 장착된 다공판 및 믹서의 형상과 배치에 따른 압력강하와 유동균일도 특성에 대한 연구를 진행하였다. 미세먼지저감 장치에 장착된 다공판 및 믹서는 미세먼지저감 장치 내의 배출가스 및 산화/환원제의 유동 균일도를 높여 배출가스 저감 성능을 높이는 긍정적인 효과와 함께 시스템의 배압을 상승시키는 부정적인 효과도 동시에 지니고 있다. 본 연구에서는 5개의 다공판, 1개의 믹서를 Case 별로 조합하여 6개의 사양에 대해서 유동해석을 통해 각각 유동균일도 및 압력 강하를 계산하였으며, 최적의 다공판 및 믹서의 형상과 배치를 선정하였다.

In this study, to investigate the effect of physical and chemical properties of butanol on the engine performance and combustion characteristics, the coefficient of variations of IMEP (indicated mean effective pressure) and fuel conversion efficiency were obtained by measuring the combustion pressure and the fuel consumption quantity according to the engine load and the mixing ratio of diesel oil and butanol. In addition, the combustion pressure was analyzed to obtain the pressure increasing rate and heat release rate, and then the combustion temperature was calculated using a single zone combustion model. The experimental and analysis results of butanol blending oil were compared with the those of diesel oil under the similar operation conditions to determine the performance of the engine and combustion characteristics. As a result, the combustion stabilities of D.O. and butanol blending oil were good in this experimental range, and the indicated fuel conversion efficiency of butanol blending oil was slightly higher at low load but that of D.O. was higher above medium load. The premixed combustion period of D.O. was almost constant regardless of the load. As the load was lower and the butanol blending ratio was higher, the premixed combustion period of butanol blending oil was longer and the premixed combustion period was almost constant at high load regardless of butanol blending ratio. The average heat release rate was higher with increasing loads; especially as butanol blending ratio was increased at high load, the average heat release rate of butanol blending oil was higher than that of D.O. In addition, the calculated maximum. combustion temperature of butanol blending oil was higher than that of D.O. at all loads.