• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.2
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• pp.85-91
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• 1998

In nuclear fuel manufacturing process, end-closure welding has long been recognized as requiring very high integrity. In this basic study, ECT(eddy current testing) method for end-closure welding has been developed to detect end cap weld discontinuities for nuclear fuel safety. In order to improve the inspection reliability, the maximum scanning speed and the maximum frequency is investigated for end-closure welding inspection. The bandpass filter(0-250Hz) is used for removing noise effects. This study shows that ECT method is effective and sensitive for the detection of small defect(0.35mm diameter).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2375-2380
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• 2013

In this paper, we have implemented the unified fuel heater and performance evaluation system for diesel cars. In order to strengthen an engine starting of diesel car, we need to assembly the fuel filter and heater. Especially, this assembly fuel heater is very important in winter, it is necessary for heating to operate the diesel engine. The heater for unifying the sensor and heater body can advance the performance of car and reduce the production cost. Finally, the performance test chamber is needed to evaluate the performance of heater.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.7
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• pp.1080-1088
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• 2008

This paper addresses some concerns faced by the shipping industry nowadays. Initially, the environmental issues were resolved and stricter regulations are now being implemented with regards to the exhaust gas, specifically nitrogen oxides (NOx) and sulfur oxides (SOx), emitted from ships. Secondly, with the increasing and unstable cost of fuel oils in the world market, it has become almost a necessity to explore on a new alternative fuel. Hence, this study was conducted. An experiment was carried-out on a fishing survey vessel with the main engine (M/E) and generator engine (G/E) operated on expensive marine gas oil (MGO). During the experiment, two pre-refinery systems were installed and different fuel oil samples were employed for the M/E and the G/E. Furthermore, the NOx emission and soot concentration were monitored and verified. The results confirmed the compatibility of some fuel oil types to the engines and meeting the emission standards. MDO, MF15 and Bunker A can be used in place of MGO for the engines(M/E, G/E).

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.3
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• pp.98-103
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• 2004

Diesel engine offers superior fuel consumption than gasoline engine of equivalent capacity. For this reason, diesel engines are widely used in heavy duty transport applications. Specially, it has been many years that exhaust gases from gasoline automobile rather than from diesel is the major object concerned by Korea and other countries, and it is strongly required on the reduction techniques on harmful NOx, Soot, CO, He. Thus, this paper focused on the emission reduction and target for this paper is heavy-duty diesel engine equipped with power filter such as wet type air cleaner. In this paper, the performance, exhaust emissions(CO, THC, NOx, Soot) and noise of heavy-duty diesel engine were measured at maximum load condition and the range of 1,000∼2,200rpm. The smoke was measured at FAS(Free Accel Smoke) test mode.

• Journal of the Korean Society of Combustion
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• v.15 no.3
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• pp.25-31
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• 2010

Combined technique of burner and DOC has been used for regeneration of Diesel Particulate Filter. Experiments has been performed to increase the temperature of engine exhaust gas to burn the collected soot in DPF at all conditions of operation of 3 liter diesel engine. Ignition temperature of soot can be successfully obtained by heats of burner flame and residual fuel oxidation at diesel oxidation catalyst even in the condition of oxygen deficiency. It is found that the load of air compressor and heat loss can be reduced to the level of practical application. It is also found that CO and THC emissions are not increase by additional combustion of regeneration burner.

• Journal of ILASS-Korea
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• v.22 no.2
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• pp.87-95
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• 2017

Recently, as the interest in environmental issues have increased around the world, the regulation on vehicle exhaust have been tightened in each country. To satisfy such tightened exhaust regulation, automotive manufactures are forced to equipped Diesel Particulate Filter (DPF) at Diesel vehicles. If DPF is used for a long time, DPF regeneration should be performed. The objective of this study is to research on post injection for DPF regeneration. The result of the study was that it was desired that retarding post injection timing, lower load of engine and smaller the amount of main fuel injection, for DPF regeneration. Oil dilution was tended to increase as load was lower, amount of post injection was increased, and post injection timing was retarded.

• Tribology and Lubricants
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• v.29 no.6
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• pp.392-396
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• 2013

Biodiesel fuels contain unsaturated fatty acid ester, which can easily oxidize, especially when exposed to ultraviolet light. The products formed by this oxidation give rise to sediment or gum formation. As a result, the fuel can contribute to the corrosion and plugging of the filter pump. Antioxidants have been used in an effort to stabilize biodiesels, but there is still a need for a biodiesel composition with improved oxidation stability. In general, good fuel compositions should provide synergistic combinations of a biodiesel and antioxidants. Our work involved the synthesis of antioxidants to improve the oxidative stability of biodiesel fuel.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.438-440
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• 2007

This paper shows a new kind of push-pull switching converter for fuel-cell system and analyses the connected characteristics of it. In these characteristics, we are concerned about the high harmonic rate of output current, we also have designed the filter system for the inverter. Besides, the characteristics should be certified better if the ripple of the fuel-cell output current has been eliminated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.6
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• pp.1292-1297
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• 2009

This study was performed to investigate solubility, dissolution rate and ash content of solid type fuel additive in gasoline and diesel in order to set up manufacturing standards. From the results, the unfiltered impurities were increased when the fuel additive was added on gasoline and diesel. Also, the unfiltered fuel additive was decreased with respect to increasing the pore size of the filter paper. When one gram of the fuel additive was dissolved in one liter of gasoline at room temperature, the best dissolution rate was about 2 hours. But, almost nothing was dissolved in diesel during 72 hours at $20^{\circ}C$ below zero. At the experiment of ash content, the gasoline which the fuel additive was melted in was showing 28 times more ash content than that was not including the fuel additive. Therefore, it seemed that almost all of ash content was caused by the fuel additive.

• International Journal of Automotive Technology
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• v.6 no.5
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• pp.437-444
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• 2005

Unburned hydrocarbon (UBHC) emissions from gasoline engines remain a primary engineering research and development concern due to stricter emission regulations. Gasoline engines produce more UBHC emissions during cold start and warm-up than during any other stage of operation, because of insufficient fuel-air mixing, particularly in view of the additional fuel enrichment used for early starting. Impingement of fuel droplets on the cylinder wall is a major source of UBHC and a concern for oil dilution. This paper describes an experimental study that was carried out to investigate the distribution and 'footprint' of fuel droplets impinging on the cylinder wall during the intake stroke under engine starting conditions. Injectors having different targeting and atomization characteristics were used in a 4-Valve engine with optical access to the intake port and combustion chamber. The spray and targeting performance were characterized using high-speed visualization and Phase Doppler Interferometry techniques. The fuel droplets impinging on the port, cylinder wall and piston top were characterized using a color imaging technique during simulated engine start-up from room temperature. Highly absorbent filter paper was placed around the circumference of the cylinder liner and on the piston top to collect fuel droplets during the intake strokes. A small amount of colored dye, which dissolves completely in gasoline, was used as the tracer. Color density on the paper, which is correlated with the amount of fuel deposited and its distribution on the cylinder wall, was measured using image analysis. The results show that by comparing the locations of the wetted footprints and their color intensities, the influence of fuel injection and engine conditions can be qualitatively and quantitatively examined. Fast FID measurements of UBHC were also performed on the engine for correlation to the mixture formation results.