• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.86-86
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• 2004

무단변속기는 속도비를 연속적으로 변화시킬 수 있고, 자동차에 적용할 경우 엔진속도를 차량속도와 독립적으로 제어함으로써 동력성능과 연비성능을 동시에 만족시킬 수 있는 장점을 가지고 있다. 무단변속기는 다양한 종류가 개발되어 사용되고 있으나, 이들 대부분은 자체적으로 중립(geared neutral)을 구현할 수 없거나 효율과 수명 측면에서 기존의 유단변속기(기어 변속기)보다 불리한 단점을 가지고 있다.(중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1345-1348
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.170-178
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• 2004

Continuously variable transmission (CVT) mechanisms considered here are input coupled types that combine the functions of a 2K-H II type differential gear and a V-belt type continuously variable unit (CVU). For the 8 different mechanisms, 4 of them are power-circulation modes while the other 4 are power-split modes, various performance analysis (speed ratios, power flows, divisions of power transmission in a differential gear and a CVU, and theoretical efficiencies) are performed to vary design parameters. Experimental studies are executed to validate fundamental relations (speed ratios, power flows, efficiencies, occurrence of geared neutral). Some useful characteristics associated with performance also are discussed in the mechanisms.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.670-673
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• 2005

We designed the compound CVT (Continuously Variable Transmissions) by combining power circulation mode CVT and power split mode CVT, which have been proposed for connecting 2K-H II differential gear to the V- belt type CVU (Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.569-573
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• 2016

Strengthened regulations for atmospheric emissions from ships have created a need for new and alternative power systems that offer low emissions and high energy efficiency. Recently, new types of propulsion power systems, such as fuel cell systems that use hydrogen as an energy source, have gained serious consideration in applications requiring emission control. The purpose of this work is to certify the availability of solid oxide fuel cell (SOFC) systems equipped with recycled steam reforming fuel processors, and to compare their performance with that of extra steam reforming systems. The results demonstrate that the recycled steam reforming system has a slightly lower cell voltage and higher energy efficiency than the extra steam reforming system.

• Journal of Power System Engineering
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• v.9 no.1
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• pp.36-41
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• 2005

This study investigated the performance of a vortex hydrocyclone for solid removal in a recirculating aquaculture system. In a fish-breeding industry, effluent water is mainly disposed by gravity sedimentation. Thus, a large settling tank and a lot of water are needed to purify effluent water. However, this typical method does not show consistent efficiency. In case of low efficiency, discharged water contains a lot of feeding sediments. This causes environmental problems. Instead of this typical method a hydrocylone is tested to discharge water which contains a lot of feeding sediments. In this paper, a hydrocyclone with low velocity and pressure drop in a recirculating aquaculture system is investigated.

• Journal of Power System Engineering
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• v.14 no.5
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• pp.56-62
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• 2010

In this paper, a recurrent cerebellar modulation articulation control (RCMAC) has been developed for improvement of noise attenuation performance in active noise control system. For the narrow band noise, a filter-x least mean square (FXLMS) method has bee frequently employed as an algorithm for active noise control (ANC) and has a partial satisfactory noise attenuation performance. However, noise attenuation performance of an ANC system with FXLMS method is poor for broad band noise and nonlinear path since it has linear filtering structure. Thus, an ANC system using RCMAC is proposed to improve this problem. Some simulations in duct system using harmonic motor noise and KTX cabin noise as a noise source were executed. It is shown that satisfactory noise attenuation performance can be obtained.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.4
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• pp.96-103
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• 2005

We designed the compound CVT(Continuously Variable Transmissions) by combining power circulation mode and power split mode, which have been proposed for connecting 2K-H I differential gear to the V- belt type CVU(Continuously Variable Unit), as an input coupled type. With the designed compound CVT, we carried out theoretical analysis and performance experiments for efficiency, speed ratio, power flow, and power transmission ratio. We proved that the compound CVT had a better performance than either of the power circulation mode or power split mode.

• Journal of Power System Engineering
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• v.16 no.4
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• pp.24-29
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• 2012

The numerical analysis by using CFX 11.0 commercial code was done for prediction of fluid flow and thermal field in the vertical heat exchanger. The present experimental studies were also conducted to investigate the effects of circulating solid particles on the fluid flow and temperatures in the fluidized bed vertical shell and tube type heat exchanger with counterflow, at which the solid particles of glasses (3 $mm{\Phi}$) were used in the fluidized bed with a smooth tube. The effect of circulation on the distance(L) of tube inlet and baffle plate was also examined. The present experimental and numerical results showed that the particles in the distance (Ds) of 15 mm showed a more efficient circulation without stacked the space and the LMTD(Log Mean Temperature Difference) in the fluidized bed type was much lower than that in the typical type shell and tube heat exchanger.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1991.06a
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• pp.70-75
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• 1991

기어는 기계시스템에서 동력전달 및 운동전환을 담당하는 기본 요소로 공작기계, 건설기계, 농업기계 등의 산업기계와 항공기, 자동차, 선박등의 운송분야, 사무용 및 계측기기 등 산업전반에 걸쳐 사용되고 있으며, 최근에는 로보트를 위시한 자동화 장치의 구동 및 동력전달 장치로 사용되고 있다. 최근의 기어시스템은 기계류의 일반적인 경향인 고속, 고부하, 결량화 추세에 따라 고정밀, 소형화되어 가고 있으며 부하한계에 가깝도록 큰 하중에 견딜것이 요구되고 있다. 따라서 기어의 설계 및 제작시, 여유있는 설계가 허용되지 않으며 정밀성을 높이기 위한 설계로, 설계인자의 세분화가 요구되어지고 있다. 국제적으로 통용되고 있는 강도설계 규격에서 면압강도시 표면상태계수(Surface condition factor)를 정의하고 있다. 본 연구에서는 동력순환식 기어 시험장치를 이용하여 표면처리 상태가 다른 3종류(열처리를 하지 않은 기어, 침탄 및 고주파 표면 열처리한 기어)의 스퍼어 기어를 이요하여 회전수별 표면거칠기의 변화 상태를 고찰하고, 변수를 응용하여 물리적 의미를 파아갛고, 윤활해석을 통한 윤활조건과 치면상태와의 상호 관계에 대하여 고찰해 보고자 한다.