• Journal of the Society of Naval Architects of Korea
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• v.55 no.6
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• pp.505-513
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• 2018

Main engine failures in ship operations can lead to a major damage in terms of the vessel itself and the financial cost. In this respect, monitoring of a vessel's main engine condition is crucial in ensuring the vessel's performance and reducing the maintenance cost. The collection of a huge amount of vessel operational data in the maritime industry has never been easier with the advent of advanced data collection technologies. Real-time monitoring of the condition of a vessel's main engine has a potential to create significant value in maritime industry. This study presents a case study on the establishment of upper control limit to detect vessel's main engine failures using multivariate control chart. The case study uses sample data of an ocean-going vessel operated by a major marine services company in Korea, collected in the period of 2016.05-2016.07. This study first reviews various main engine-related variables that are considered to affect the condition of the main engine, and then attempts to detect abnormalities and their patterns via multivariate control charts. This study is expected to help to enhance the vessel's availability and provide a basis for a condition-based maintenance that can support proactive management of vessel's main engine in the future.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.105-108
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• 2005

The radiated noise from the automotive intake system should be predicted at the design stage. To this end, the precise measurement of in-duct acoustic source parameters of the intake system, i.e., the source strength and source impedance, is essential. Most of previous works on the measurement of acoustic source parameters were performed under a fixed engine speed condition. However, the requirement of vehicle manufacturer is the noise radiation pattern as a function of engine speed. In this study, the direct method was employed to measure the source parameters of engine intake system under a fixed engine speed and engine run-up condition. It was noted that the frequency spectra of source impedance hardly changes with varying the engine speed. Thus, it is reasonable to calculate the source strength under the engine run-up condition by assuming that source impedance is invariant with engine speed. Measured and conventional source models, i.e., constant pressure source, constant velocity source, and non-reflective source, were utilized to predict insertion loss and radiated sound pressure level. A reasonable prediction accuracy of radiated sound pressure level spectra from the intake system was given in the test vehicle when using the measured source characteristics which were acquired under the operating condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.67-74
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• 2001

A synchronized secondaty air injection method has been developed to hydrocarbon emission by injecting secondary air intermittently into exhaust port. The method has been tested in a single cylinder spark-ignition engine operating at cold-steady / cold-start conditions. Effects of air injection timing, intake pressure and engine air-fuel ratio have been investigated at cold-steady condition. Also, hydrocarbon emission and exhaust gas temperature with catalytic conberter are compared with a continuous SAI method and base condition at cold-start condition. Resules show that hydrocarbon reduction rate and exhaust gas temperature are sensitive to the timing of synchronized SAI. At cold-steady condition, HC emission is minimum at engine air-fuel ratio of 10. At cold-start condition, the accumulated hydrocarbon emission during the first 120 s decreases about 56% and 22% with the synchronized and continuous SAI, respectively, compared to that of base condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.494-501
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• 2015

Nowadays, many people are trying to develop eco-friendly engines such as the electric motor and the air engine because the I.C. engine cause a lot of pollutants. Nevertheless of these effort, there are few evaluation and comparison of these engines to conventionally used I.C. engines. Because of this, it is difficult to determine that the eco-friendly engines are really energy saving engines. In this paper, the efficiency of the air engine is calculated. The air engine does not cause environmental pollution problem because it uses "Compressed air". Due to the air engine operated at a low temperature and spark-free condition, this engine can be used in extreme condition for safety. Despite the many advantages of the air engine, there are few analysis on the air engine because of an air engine is low energy density.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.581-586
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• 2014

In general vibration test considers both harmonic vibration and random vibration, When developing the vehicle component. But the effect of harmonic vibration is larger in the parts around the vehicle engine, sole testing the harmonic vibration is considered. In this study, the fatigue damage of the linear system fixed around the engine is analyzed when the effect of random vibration is higher, harsher than the normal road surface condition. In condition the vehicle speed and the engine RPM are similar, the higher the harshness of the road surface condition is, the larger the fatigue damage level is. Therefore both random vibration and harmonic vibration must be considered in vibration test of components around the engine. Proposing the sine on random(SOR) vibration test that can exam considering both of vibrations, harmonic and random.

• Journal of Biosystems Engineering
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• v.2 no.1
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• pp.1-6
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• 1977

The dilution of crankcase oil with unburned portions of the fuel during operating is one source of the oil contaminations which will reduce engine life.It has been learned that major causes of oil dilution may be the result of using impure fuels which were mixed with water, dust, and some others, but very little was known about this. This study was conducted to develop a more intimate understanding about oil dilution of the farm kerosene engine while using impure fuel mixed with expecially diesel. Fuels being used in this study were 9 kinds of mixed fuels, kerosene and diesel. Farm kerosenen engine of 10 P.S. was tested at no-load of 1000 and 2000 rpm., such as 1/4, 2/4, 3/4, 4/4, and 11/10 loads for understanding about oil dilution of keresene engine.The result of this study are summarized as follows : 1. The amounts of oil dilution of the engine being tested was increased with increase in the applied loads and the contents of diesel in the mixed fuels when using fuels other than kerosenen and diesel, whereas at $D_100$ fuel the comount of oil dilution decreased in some cases. The lowest value was measured to be 20 cc/hr, at $K_90$ fuel of no-load condition, and the highest value to be 293cc/hr. at $K_{10}$ fuel of 4/4 load condition. 2. When the engine was operated at no-load condition, the amount of oil dilution at 100rpm. was much more than at 2000 rpm. 3. Because the fuel consumption and the oil dilution showed a similar tendency along the applied loads, the excessive fuel consumption of engines was supposed to be one of the important factors affecting oil dilution. 4. The temperature of crankcse oil was varied invesely with oil dilution, but they were not thought to be factors to determine each other variable. 5. The tested engine could be operated with high percentage of diesel mixed fuel from no-load condition to fully loaded condition, but it would be impossible to operate the engine for long hous continuously due to excessive speed fluctuation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.04a
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• pp.17-20
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• 2001

Combustion characteristics of KSR-III liquid rocket engine are investigated numerically in the standpoints of engine performance and acoustic instability. In the present calculation, engine performance for design and off-design conditions is estimated effectively with reasonable error. Numerical results of acoustic instability show that engine operation for the design condition has sufficient stability margin, but for a certain off-design condition, acoustic instability can be triggered by artificial pressure perturbation. The present results are in a good agreement with the available experimental results and can be adopted for the prediction of engine performance and stability, depending on the specific operating condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.6
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• pp.61-66
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• 2012

Conventional method to transform vehicle driving condition to engine operation mode is to use vehicle road load under neutral gear and mechanical efficiency of drivetrain. But this method requires additional measurement of efficiency of drivetrain on a test rig. And this measurement is normally done at fixed speed and thus estimated accuracy of engine operation mode is not considered to be high enough. This study suggests new method to calculate engine operation mode for prescribed driving mode such as NEDC using vehicle coastdown test under gear engaged condition without measurement of mechanical efficiency of drivetrain. Coastdown test was done under neutral and gear engaged condition for comparison and also trial to extract mechanical loss of drivetrain was carried out. Calculated engine torque by conventional and newly suggested method was compared with actually measured torque of a vehicle on a chassis dynamometer during NEDC. Newly suggested method showed slightly higher accuracy of accumulated brake work during NEDC.

• Journal of Power System Engineering
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• v.13 no.5
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• pp.82-88
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• 2009

The purpose of this paper is to provide technical background, techniques and actual diesel engine signature analysis evaluation result. Engine signature analysis(ESA) is a process for monitoring the material condition of diesel engine using external sensors, eliminating the need to periodically disassemble the engine. ESA is also used to balanced the engine. Engine balancing is the process of tuning the engine so that all cylinders carry equal load. ESA is a useful tool to non-intrusively determine the operability and performance and assessment of the material condition of internal component of a diesel engine.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.488-491
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• 2005

This paper has been proposed an engine oil changing system automatically using artificial intelligence. As you know, It is very difficult to forecast the time that exchange engine oil exactly. Because, It does not necessary to change the engine oil when color of engine is black or distance is more than 3000 km. In order to forecast to optimal engine oil replacement time, We must to consider color of engine oil, greasy, mad condition, quick starting condition and quick braking condition. Therefore, in this paper, to overcome those problems, we, developed an expert system that it can forecast to exchange time of engine oil automatically using fuzzy rules and neural networks.