• Journal of Advanced Marine Engineering and Technology
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• v.36 no.7
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• pp.885-893
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• 2012

DME (Dimethyl ether) is regarded as one of the candidates of alternative fuels for diesel engine, because of its higher cetane number suitable for a compression ignition engine. Also, DME is a simple chemical structure, colorless gas that is easily liquefied and transported. On the other hand, Bunker oil (JIS C heavy oil) has long been used as a basic fuel in marine diesel engines and is the lowest grade fuel oil. In this study, the combustion and emission characteristics were measured experimentally in the direct injection type diesel engine operated with DME and Bunker oil mixed fuel. From our experimental results, it is induced that DME and Bunker oil blended fuel would be an effective fuel which can reduces the concentration of harmful matter in exhaust gases.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.551-558
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• 2004

Recently, fuel prices have been continually raised in diesel engine. Such a change in the fuel price influences enormously the development trend of marine diesel engines for slow speed, In other words, the focus was shifted from large diameter and high speed to low fuel consumption. Accordingly, more efforts are being made for engine manufacturing and development to develop highly efficient engines. In this study. a single cylinder 4 stroke cycle DI slow speed diesel engine was designed and manufactured, a 4 stroke cycle was configured and basic performances were evaluated. The results are as follows. The optimal fuel injection timing had the lowest value when specific fuel consumption was in BTDC 8~$10^{\circ}$, a little more delayed compared to high speed diesel engines. Cycle variation of engines showed about 5% difference at full loads. This is a significantly small value compared to the cycle variation in which stable operation is possible, showing the high stability of engine operation is good. The torque and brake thermal efficiency of engine increased with an increase of engine 250-450 rpm. but fuel consumption ratio increased from the 450 rpm zone and thermal efficiency abruptly decreased. Mechanical efficiency was maximally 70% at a 400 rpm that was lower than normal engines according to the increase of mechanical frictional loss for cross head part. The purpose of this study was to get more practical engines by comparing the above results with those of slow speed 2 stroke cycle diesel engines.

• Journal of Environmental Health Sciences
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• v.38 no.4
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• pp.277-290
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• 2012

Objectives: Diesel engine exhaust (DE) accounts for a significant percentage of air pollutants that are associated with various health outcomes including mortality, asthma, chronic bronchitis, respiratory tract infection, etc. In June, 2012, the International Agency for Research on Cancer (IARC) released the assessment results that classified DE as "carcinogenic to humans" (Group 1). This review is therefore focused on the lung cancer risks of DE. Methods: Literatures were searched using PubMed with key words of "diesel exhaust", "lung cancer", and other related terms for the period between 1990 and 2012. A total of 295 articles were searched and sixteen epidemiologic studies were identified as potentially relevant. Results: Sixteen epidemiologic studies about the lung cancer risks of workers exposed to DE in various occupations were summarized in two tables, 1) retrospective cohort studies and 2) case-control studies. Increased lung cancer risk, although not always smoking adjusted, was observed in 6 out of 8 retrospective cohort studies and 4 of 8 case-control studies. Conclusions: Diesel fuel is widely used in Korea. Exposure to DE is confirmed to be a human carcinogen by IARC. Noncancer health risks of DE also need careful attention as DE is a major source of fine-particle pollution. Along with the efforts for reducing the DE emission through improvements of diesel engines and fuel, and the use of alternative fuels, comprehensive health risk assessment of DE should be conducted to minimize the adverse health effects.