• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.332-336
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• 2008

A pulsation damper is usually mounted on the fuel rail to diminish undesirable noise in the vehicle cabin room. However, pulsation dampers are quite expensive. Therefore, several studies have focused on reducing fuel pressure pulsations by increasing the self-damping characteristics of the fuel rail. This paper is a basic study in the development of a fuel rail that can reduce pulsations via a self-damping effect. In this study, the pressure pulsation characteristics were of investigated with respect to the aspect ratio of the cross section, wall thickness, and fuel rail material through oil hammer simulations. An oil hammer simulation was performed in advance to simulate the pressure pulsations at the resonant speed, which is a time-saving way. The pressure pulsation peak of fuel rail was observed to rise as the injection period increases. Increase of the aspect ratio and decrease of the wall thickness can reduce the pressure pulsation efficiently.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.4
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• pp.490-495
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• 2011

A slide-rail system is widely used in home appliances, furniture, mechanical rigs, and so many other applications; due to its high strength and performance for easy moving heavy objectives. In general, a pair of side slide-rails is set on both sides of a drawer to support and move it. So an unbalanced sliding motion can occur during opening and closing a drawer with pull and push force. To settle this problem, single central slide-rail having three collapsible rail-bodies was firstly proposed in this work. 'H'-beam shaped rail-body was newly designed to have enough bending and twisting strength. The experimental test showed that the proposed rail could be applied to large-size home appliances for easy moving drawer with heavy weight.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.685-697
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• 2016

Railroad is considered as an eco-friendly transportation mode because it emits lower greenhouse gases and air pollutants and consumes less energy compared to trucking. To promote rail freight, many countries have implemented various policies, while South Korea has implemented few substantial policies. This study aims to compare and analyze rail freight policies of various countries in order to suggest policy implications to South Korea. We analyze relevant policies of 9 countries; these are classified into 5 categories, and we provide policy implications for facilitating rail freight infrastructure and equipments, grants for the transportation cost using freight rail, and road freight restriction policy.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.186-192
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• 2007

In general, pulsation damper is installed in fuel rail for conventional MPI engine to decrease undesirable noise in vehicle cabin room. However, pulsation damper is so expensive that there are prevailing studies to reduce fuel pressure pulsations with integrated damping effect. This paper is one of basic studies for development of fuel rail to abate pulsations with self-damping effect. Primarily, the pressure pulsation characteristics was investigated with aspect ratio of cross section, wall thickness, and materials of fuel rail. A high aspect ratio or thin wall was found to absorb the pressure pulsations effectively. But volume effects on the fuel pressure pulsation reductions were not especially significant than cross section effects because volume increment rate is larger than pressure pulsation reduction rate. The fuel rail made of aluminum is effective for reduction of pressure pulsation than that of low-carbon steel. Pressure change period increases on the basis of same lengths of supply line and fuel rail as the volume is enlarged and/or the thickness of wall is thinned.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.507-512
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• 2003

The railroad is a means of large transportation which has many latents such as a safety and a regularity. That is a results from various confidential performance tests and evaluations of the system. The railroad system consist of various subsystems - vehicle, power supply, signal, communications, track structures, operations, etc. Among them, as an item of safety evaluation there is a measurement of wheel/rail force, so called a measurement of derailment coefficient. This is a very important item because a derailment of a train will bring about a big accident. Especially it is more important in high speed rail of which operation speed is over two times as fast as existing rail. In this paper, it is introduced to preprocess the wheelset for measuring wheel/rail force of high speed rail, such as to treat a measuring wheelset, its finite element analysis, adhesion of strain gauges and static toad test, running test result of main line.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.922-927
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• 2007

The present urban maglev which has been developed in Korea is controlled by 4-edge control method over each bogie. The control output which is derived from two gap sensors and one vertical acceleration sensor controls magnet to maintain a nominal gap. But, the gap signal acts as a big disturbance in rail joint though two gap sensors are used and finally result in unstable response and poor ride comfort. This paper treats of a method to compensate the gap signal in rail joint for the levitation control of urban maglev. The physically abnormal change of gap is detected when one gap sensor passes a rail joint, the disturbance of gap in rail joint is estimated. Finally the disturbance in gap signal is eliminated by processing the information of vehicle speed and estimated disturbance in when the other gap sensor passes a rail joint.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.2
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• pp.28-34
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• 2001

Great attentions are paid to HSDI diesel engine for passenger cars because of its high thermal efficiency. The most interesting research in HSDI diesel engine developments is focused on applying common rail system as a fuel injection equipment. In this study, a series of tests are carried out to investigate the effect of injection pressure variation on the smoke and fuel concluded in a small HSDI diesel engine with common rail system. As a result of this study it is concluded that there is an optimum rail pressure dependent on combustion system such as nozzle type, combustion chamber geometry.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1318-1326
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• 2009

Moscow is one of well-developed city about intermodal transport system by subway line. But some airports which located in suburb area have really bad transport system connecting downtown Moscow, and many people have experienced a lot of inconveniences. Russian Railways (RZD) established airport rail company in year 2005 and they have operated Aero-Express train from downtown of Moscow to major airports. Intermodal transport system was considered to the construction of Russian airport rail system, and various types of tickets and airport rail terminals are operated by RZD, and subsidiary businesses with airline companies are promoted. This study will analyze the success factors of Moscow airport rail system and introduce the success effects, and considering points for the operation of Incheon airport rail terminal in the future.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.119-126
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• 2009

The noise emitted during train operation is generated with various reasons. It is known that the major noise generation is classified according to the ranges of train speed; that is, engine noise at lower speed range, rolling noise at medium speed range, and air-borne noise at higher speed range. These noises are transmitted in combined form with the noises generated from track components and under-carriage, etc. The rolling noise as a major noise at medium speed range is caused by the vibration occurred at wheel/rail interface. The vibration occurred at wheel/rail interface is transmitted to wheel and rail, and this vibration is emitted from wheel and rail as a noise. In this paper, a soundproof box which can simply measure the noise emitted from rail and analyze the characteristics of the measured noise is studied.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.462-467
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• 2005

Design standard specifications for structures applied to Seoul-Pusan High Speed Rail construction were established in 1991. Those specifications have been changed and supplemented in the process of above construction, and need to improve in accordance with the new criteria for construction works of Korean government. Also, a settlement of the criteria for prevention against disasters of Seoul-Pusan High Speed Rail is needed, and related specifications have been revised. The design criteria for Seoul-Pusan High Speed Rail are enacted with knowhow which resulted from High Speed Rail construction, and those are enacted for the purpose of establishing criteria for High Speed Rail construction in the inside and outside of Korea.