• Proceedings of the KSR Conference
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• 2000.11a
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• pp.521-526
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• 2000

Experimental study is conducted to clarify pressure variation of the passenger cabin of conventional train. These pressure variation may give rise to the ear-discomfort. Generally ear-discomfort has been considered as a problem related to high speed train. Because there is also a good progress to speed-up for conventional line, this isn't only a phenomena related to high speed train any longer. In this study, tile pressure variation of interior, gangway and exterior of saemaeul passenger car is measured using the atmospheric pressure sensors in Honam line. From the results of experiment, the pressure variation per second almost close in upon the limitation in the case of Noryong tunnel. Therefore, to accomplish speed-up for conventional train, it may be necessary to study a serial ventilating and the airtightness of carbody.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.1389-1396
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• 2008

There are many studies on the ride comfort for the train from the viewpoint of passenger. But there are only a few studies on the ride comfort for engineers in the locomotive. The railway has the track conditions, such as irregularities, rail joints, turnout, level crossing, transition curves and super-elevation ramps, which cause vibrations. Generally, the ride comfort for the train is evaluated by using the vibrations. In this study, vibration accelerations have been measured in the cabin rooms of locomotives, such as DL(Diesel-electric Locomotive), DHC(Diesel Hyduralic Car) and NEL(New-Electric Locomotive) when running on the Kyoungbu conventional line. And then, their ride comforts has been analyzed and evaluated by statistical method according to UIC 513R.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.495-502
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• 2000

For the tunnel design of the first class on new Seoul-Chunchon railway, we investigated for train speeds to run through tunnels without ear-discomfort of passenger in cabin by application of numerical analysis. Also we analyzed the effect of the wind speed induced by train in tunnel that is very harmful to the workers on railroad and the effect of the air-pressure fluctuations which get the fatigue to the tunnel lining and the car body.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.135-141
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• 1996

Numerical analysis techniques have been applied to obtain the vibroacoustic characteristics of the simplified model of a passenger-car cabin. Two kinds of coupled vibration-acoustic analysis, such as one-way coupling and full coupling, have been carried out via the interface between the results of vibration analysis by FEM and acoustic analysis by BEM. The comparison of two coupled analysis results show the fluid-structure interaction in terms of the coupled effect of the vibration and noise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7250-7255
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• 2015

The objective of this study is to experimentally investigate the heating performances of the portable air combustion heater using diesel fuel for auxiliary cabin heating of the battery electric vehicle. In order to evaluate the heating performances of the air combustion heater, the heating capacity was calculated by the temperature at inlet and outlet parts of the considered heater and the inner temperature distribution characteristics of the vehicle were measured during 1600 seconds with an interval of 1 second. The theoretical efficiency of the tested heater was calculated by temperature data of the air of supplying and exhausting to the cabin. As the air passed the heat-sink, the air temperature at the end of heat-sink reached to $101.3^{\circ}C$ and the difference of temperature on heat-sink was 67.8%. The average heating capacity of the air combustion heater showed 2.0 kW. After 1800 seconds, the inner temperature of the vehicle cabin was continuously increased. The temperatures of the top side and the bottom side of the car cabin under consideration were increased upto $42.5^{\circ}C$ and $24.3^{\circ}C$, respectively, and the theoretical efficiency of the tested heater was on average 63.7%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1104-1108
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• 2007

Automobile sunroof buffeting is the tonal noise of low frequency around 20Hz. It occurs due to the acoustic feedback process between the shear layer detached from the leading edge of sunroof opening and the Helmholtz resonator-like property of a car cabin. In this paper, PIV visualization technique is applied to the unsteady flow field around sunroof opening of an SUV in the full-scale automotive wind tunnel in order to find out buffeting mechanism. A phase-marking PIV measurement method, in which image and sound pressure are recorded simultaneously, and a phase-rearrangement post-processing program were developed for capturing noise-related velocity fields without expensive synchronization systems. Through this study, some characteristics of the real-car sunroof shear layers under various deflector conditions were identified and these results can provide insights into the noise reduction mechanism of the tube-type deflector.

• Journal of Welding and Joining
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• v.31 no.3
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• pp.22-30
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• 2013

Due to ELV banning, automotive electronics cannot use four kinds of heavy metal element (Pb, Hg, Cd, $Cr^{6+}$) from 2016. Therefore, this study was focused on degradation characteristics of Sn-3.0Ag-0.5Cu Lead-free solder joint with OSP and ENIG finsh under various reliability assessment method, as like to thermal shock test and high temeprature/high humidity test with test duration for cabin electronics. Also, we compared bonding strength degradation to other advanced research results of electronic control unit for engine room because of difference service temperature with mount location in automotive. Whisker growth phenomenon and mitigation method which were essentially consideration items for Pb-free car electronics were examined. Conformal coating is a strong candidate for mitigating whisker growth in automotive electronics. Necessary condition to adapt Pb-free in car electronics was shown.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.280-285
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• 2003

The process of railway traffic planning is composed of several steps such as long-term, mid-term. short-term, and real-time plan. The planning of vehicle and manpower resources is a main research topic in tactical short-term planning step. Railway vehicle is usually consisted of a power car, passenger/freight cars and human resource is composed of engine driver, cabin crew, ground personnel. So far, power car was main research target in railway vehicle scheduling problem. Recently according as the light electric railway or high-speed railway is introduced, the operational planning of trainset vehicles become important, In this paper, we introduce the conceptional model for trainset restoring problem and developed heuristic algorithm.

• Proceedings of the Safety Management and Science Conference
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• 2003.05a
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• pp.53-61
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• 2003

The process of railway traffic planning is composed of several steps such as long - term, mid - term, short - term, and real - time plan. The planning of vehicle and manpower resources is a main research topic in tactical short - term planning step Railway vehicle is usually consisted of a power car, passenger/freight cars and human resource is composed of engine driver, cabin crew, ground personnel. So far , power car was main research target in railway vehicle scheduling problem. Recently according as the light electric railway or high - speed railway is introduced, the operational planning of train set vehicles become important . In this paper , we introduce the conceptional model for trainset restoring problem and developed heuristic algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1093-1098
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• 2001

The interior sound pressure level of the Korean high speed train is predicted using ray acoustic method. The motor car, motorized car and passenger cabin are investigated under the environment of passing open countryside and inside tunnel Calculated sound levels of KHST are compared with the those of KTX prototype which vehicle shows similar acoustic behavior with KHST for the purpose of assuring the calculated data. In order to reduce the calculated SPL in systematic way, contribution analysis of sound sources and sensitivity analysis of concerning wall's transmission loss on the SPL of the designated receiving points are carried out. Finally, practical design suggestions are proposed.