• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1019-1021
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• 1999

In this paper, we describe the design and appliance of the preventive diagnostic expert system of gas in oil for power transformer. This expert system is developed to use expert system development tool; Element Expert (NEURON DATA Inc.) Analysis is developed by four diagnose methods. In first, the standard of KEPCO is applied. It classifies the state of transformer by four level: Normal, warning, abnormal and danger. And the others are gas pattern methods, IEC code method, and Dornen & Roger Ratio method and applied later. These latter methods analyse the cause of result. Inference engine was designed with Element Expert. In last, we operate the system with sample data and we can obtain the correctly inferred result for the state of transformer.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.4
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• pp.36-41
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• 2015

The cyclone separator is a simple device, which causes the centrifugal separation of materials such as droplets or particles in a fluid stream. The cyclone separator utilizes the energy obtained from fluid pressure and linear motion to create rotational fluid motion. This rotational motion leads the materials suspended in the fluid to separate from the fluid quickly due to the centrifugal force. The rotation is produced by the tangential or involuted introduction of fluid into the vessel. These materials may be droplets of fuel in blow-by gas through an engine. Droplets suspended in the feed liquid may separate according to size, shape, or density. And the change of part dimension in a cyclone separator can yield the its performance variation. The current study shows the influence of design parameters on the performance of a cyclone separator for blow-by gas.

• Journal of the korean Society of Automotive Engineers
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• v.18 no.2
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• pp.64-71
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• 1996

내연기관은 19세기에 발명되어 20세기에 이르는 약 100여년에 걸쳐 계속 발달하여, 오늘날은 육.해.공의 각종 원동기로 사용되어 인간생활에 없어서는 안될 중요한 위치를 차지하고 있다. 사용연료는 거의가 액체연료인 석유계가 대부분을 차지하고 있고, 이의 수요가 날로 증가됨으로써 석유자원의 고갈 위기와 함께 유해성 배출가스의 방출에 기인되는 환경오염의 측면에서도 매우 심각한 문제로 대두되고 있다. 따라서 종래의 석유계 연료로부터 탈피하여 값싸고 장기적으로 안정하게 고급될 수 있는 대체연료 개발과 에너지 절약기술에 대한 다각적인 연구가 전 세계적으로 확산되고 있다. 이러한 대체연료는 단순히 가격면에서 뿐만 아니라 장기적 공급이 가능해야 하고 또한 석유자원의 고갈과 비상시의 대비를 위한 관점에서도 취급되어야 할 것으로 본다. 이러한 관점에서 어유는 어류의 자원이 고갈되지 않는 한 생산이 계속 가능하므로 대체연료로서의 이용가치를 검토할 필요가 있다고 본다. 따라서, 본 해설에서는 디젤기관용 대체연료로서 가격이 싸고 공급이 비교적 용이한 정어리유(sardine oil)를 경유와 여러비율로 혼합한 경유-어유 혼합유를 정용연소기와 선박용 디젤기관에 사용하여 그 연소특성을 기존의 경유 사용시와 비교 설명하고자 한다.

• Journal of Sensor Science and Technology
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• v.14 no.3
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• pp.150-155
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• 2005

We propose a newly developed automobile sensor monitoring system incorporated with a tire pressure monitoring sensor(TPMS). The RF-transmitter based on a tire pressure sensor, sends a frame data about measured tire-pressure to RF receiver. And the various sensing signals based on sensors such as fuel-level sensor, engine oil level sensor and temperature sensors, are converted into 10-bit digital data. The microprocessor displays converting data such as tire pressure, trip distance, fuel quantity, coolant temperature and car-room temperature, on LCD panel. The proposed system can be successfully adapted to monitoring of the tire pressure and various automobile sensors.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.174-181
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• 2002

Dynamic deformation of the cylinder bore during actual engine operation has an important effect on the combustion gas sealing, oil consumption, friction and so on. The dynamic analysis using the finite element method is performed to investigate the dynamic deformation of the cylinder bore subjected to forced vibration under excitation of the combustion gas pressure. However, this analysis requires large computer memory and tremendous solving time. The pseudo-static analysis can be an alternative to the dynamic analysis at the expense of accuracy. Dynamic analysis and static analysis results are presented for both closed-deck block and open-deck block that are respectively combined with the cylinder block, cylinder head, transmission, and oil pan.

• Tribology and Lubricants
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• v.12 no.3
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• pp.12-25
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• 1996

The friction and wear behaviors of ceramics against steels with lubricants were investigated and compared with those observed in air. Lubrications wbre done by a water and a commercial engine oil as received. The investigated ceramics were $Al_{2}O_{3}$, SiC, and $Si_{3}N_{4}$. Steels with 0.2 wt.% C were heat treated to obtain tempered structure. A cylinder-on-plate tribometer with rotated sliding motion was used to carry out the experiments. In the experiments reported here, the ranges of different testing speeds and loads were used. It was found that the friction and wear characteristics of tested pairs were significantly influenced by environments. In water and oil environments the wear of ceramics was reduced from 10$^{-6}$ g/s down to 10$^{-8}$ g/s in dry sliding at the same values of the frictional power which are the products of the friction coefficient, the load and the sliding speed. SiC showed excellent wear resistant behavior in water sliding, which was the lowest among tested ceramics, but it was, very poor in oils. In case of $Si_{3}N_{4}$, the wear rates were very low under oil environment, but the highest in water. The wear rates of $Al_{2}O_{3}$ were very low in both lubricating conditions at low values of the frictional power, but high at high values of the frictional power.

• Tribology and Lubricants
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• v.25 no.1
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• pp.56-60
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• 2009

A journal bearing is used in a hydrodynamic lubrication state, but it becomes a boundary lubrication state that asperity of a contact part touch each other when pressure is too high and an enough oil film is not formed by viscosity change due to lubricating oil temperature. At this time, abrasion due to contact between a journal and a bearing is unavoidable, and scuffing damage that the journal adheres to the bearing occurs if the process is repeated. Damage of the journal bearing is an important problem because it gives huge damage to a machine and can generate large accidents such as economic loss and human life damage. In this study, method for using the pull-up resistor concept was introduced as the monitoring technology. This monitoring system is important to enhance reliability of the engine.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.307-310
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• 2000

Recently, the demand for the Floating, Production Storage, and Offloading facility(FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. The basic characteristics of a 343,000 DWT class FPSO which is being built in Hyundai Heavy Industries and shall be installed in offshore Angola, is almost same as that of oil carriers. However, she do not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise source contributing to the cabin noise of the accommodation, are classified into the machine in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is much severer than that of the common commercial ships and the maximum acceptable sound pressure level of cabins is specified in 45dB(A). This paper describes the procedure of noise analysis along with its results. Noise analysis has been carried out for the case of emergency diesel generator running condition and the case of normal production condition and the results has been compared with the measurement results of the first case. Based on the results, proper countermeasures to reduce excessive noise level has been applied considering the characteristics of sources and receiver spaces and can be satisfied the specifications at all spaces.

• Journal of Preventive Medicine and Public Health
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• v.29 no.4 s.55
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• pp.785-799
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• 1996

We investigated the 1,004 workers who worked in a automobile factory to study the epidemiologic characterists of dermatoses due to cutting oils. Among the workers, 667(66.4%) answered the questionaire. They are belong to 5 departments of the factory-the Engine-Work(258 workers), Gasoline engine Assembly(210), Diesel engine Assembly(96), Power train Work(86), Power train Assembly(17). We measured the oil mist concentration in air of the departments and examined the workers who had dermatologic symptoms. The results were follows; 1) Oil mist concentration ; Of all measured points(52),9 points(17.2%) exeeded $5mg/m^3$- the time-weighed PEL-and one department had a upper confidence limit(95%) higher than $5mg/m^3$. 2) Dermatologists examined 213 workers. 172 of them complained any skin symptoms at that time - itching(32.5%), papule(21.6%), scale(15.7%), vesicle(12.5%) in order. The abnormal skin site found by dermatologist were palm(29.3%), finger & nail(24.6%), forearm(16.2%), back of hand(8.4%) in order. 3) As the result of physical examination, we found that 160 workers had skin diseases. Contact dermatitis was the most common; 69 workers had contact dermatitis alone(43.1%), 11 had contact dermatitis with acne(6.9%), 10 had contact dermatitis with folliculitis(6.3%), 1 had contact dermatitis with acne & folliculitis, and 1 had contact dermatitis with abnormal pigmentation. Others were folliculitis(9 workers, 5.6%), acne(8, 5.0%), folliculitis & acne (2, 1.2%), keratosis(1, 0.6%), abnormal pigmentation (1, 0.6%), and non-specific hand eczema (47, 29.3%). 4) The prevalence of any skin diseases was 34.0 pet 100 in cutting oil users, and 13.3 per 100 in non- users. Especially, the prevalence of contact dermatitis was 23.0 per 100 in cutting oil users and 23.0 per 100 in non-users. 5) We tried patch test(standard serise, oil serise, organic solvents) on 49 patients to differentiate allergic contact dermatitis from irritant contact dermatitis and found 20 were positive. 6) In a multivariate analysis(independant=age, tenure, kinds of cutting oil), the risk of skin diseases was higher in the water-based cutting oil user and both oil user than non-user or neat oil user(odds ratio were 2.16 and 2.78, respectively). And the risk of contact dermatitis was much higher at the same groups(odds ratio were 5.16 and 6.82, respectively).

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.370-376
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• 2022

Smart ships related studies are being conducted in various fields owing to the development of technology, and an engine room patrol robot that can patrol the unmanned engine room is one such study. A patrol robot moves around the engine room based on the information learned through artificial intelligence and checks the machine normality and occurrence of abnormalities such as water leakage, oil leakage, and fire. Study on engine room patrol robots is mainly conducted on machine detection using artificial intelligence, however study on movement and control is insufficient. This causes a problem in that even if a patrol robot detects an object, there is no way to move to the detected object. To secure maneuverability to quickly identify the presence of abnormality in the engine room, this study experimented with whether a patrol robot can determine the shortest path by applying the A* algorithm. Data were obtained by driving a small car equipped with LiDAR in the ship engine room and creating a map by mapping the obtained data with SLAM(Simultaneous Localization And Mapping). The starting point and arrival point of the patrol robot were set on the map, and the A* algorithm was applied to determine whether the shortest path from the starting point to the arrival point was found. Simulation confirmed that the shortest route was well searched while avoiding obstacles from the starting point to the arrival point on the map. Applying this to the engine room patrol robot is believed to help improve ship safety.