• Journal of Power System Engineering
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• v.6 no.4
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• pp.30-35
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• 2002

This study represents the effects of the material of the air cleaner on the performance in a 4-stroke spark-ignition engine for motorcycles. This study is mainly focused on the possibility of the adopting the STS wire mesh air cleaner of a S.I engine. For investigating the possibility of that, the engine power, the fuel consumption and the exhaust gas analysis were carried out for the synthetic fiber air cleaner and the different size of 200 mesh, 250 mesh, 300 mesh of STS wire mash air cleaner. As the results of this study, the performance of STS wire air cleaner was similar to the fiber air cleaner at 9000 rpm but 300 mesh of STS air cleaner had a high engine power and torque at 9500 rpm. In the case of the synthetic fiber air cleaner the concentration of CO was low at 6500 rpm and in the case of the 300 mesh in STS wire mesh air cleaner the concentration of HC was lowest at all experimental regions.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.2
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• pp.153-159
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• 2016

In this paper, a mechanism of an omni-directional personal mobility which can drive diagonally is proposed. Mobility is a prerequisite involved in basic human life and activities. Personal mobility vehicle is a new mobility method which overcome the limits of automobiles. However, personal mobilities with four wheeled structure still have limitations. The proposed personal mobility vehicle can overcome the limitations of mobility because its rear wheels can be steered omni-directionally. In addition, the handicapped can drive it through a narrow road such as an alleyway or corridor and avoid obstacles on the traveling route. The proposed mechanism of personal mobility and the steering performance are tested by experiments, and the feasibility of diagonal driving is verified.

• Journal of the Korea Convergence Society
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• v.9 no.8
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• pp.179-184
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• 2018

The driving methods of car are front wheel drive, rear wheel drive and four wheel drive. At driving methods, constant velocity joint is the most important part at carrying out two functions for converting to the direction which the driver wants and transferring the power to wheels. At driving on the road, the impact can be applied to the parts transmitting power according to the state of road surface. In this study, each models of three constant velocity joints whose shaft length are different respectively were modelled with CATIA and the structural and fatigue analyses were carried out by using ANSYS. This study result is thought to be the useful material at designing the constant velocity joint with the durability against impact. And it is possible to be grafted onto the convergence technique at the design of constant velocity joint and show the esthetic sense.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.1
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• pp.144-151
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• 2008

The bi-modal vehicle is composed of two car-bodies and three axles. Each axle of the vehicle has an independent suspension and all wheels are steerable. Since the bi-modal vehicle has longer wheelbase than most urban buses, the All-Wheel-Steering(AWS) system is adapted for to ensure safe driving and proper turning radius on a curved road. This paper proposes an AWS control algorithm for stable driving of bi-modal vehicle. Steering angles and directions of each axle of bi-modal vehicle changed according to the driving environment and steering modes. In the case that front and rear axles should be steered in opposite directions is a negative mode, and the other case that the axles should be steered in the same direction is a positive mode. For example, in the positive mode, front and real axles are steered in the same direction, while in the negative mode, they are steered in the opposite direction. A multibody model of the vehicle is used to verify the performance of the steering algorithm and simulation results of 2WS are compared with those of AWS under the same condition.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.77-83
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• 2020

4WD technology is being actively applied to passenger cars. Therefore, dry multi-plate clutches are used for transfer cases. On the other hand, dry clutches have problems related to large vibrations and poor ride quality. To solve this problem, this paper proposes a multi-plate clutch with an MR fluid. When fastening the multi-plate clutch in the transfer case, the proposed MR clutch was applied to reduce the shock and friction, which is a key component in a four-wheel-drive system. MR multi-plate clutch has a fluid coupling mode and a compression mode. A torque model equation was derived for the optimal design. The analysis was performed using Ansys Maxwell to optimize the design parameters of the multi-plate clutch. Electromagnetic field analysis confirmed the strength of the magnetic field when the number of disks and plates were changed, and the maximum strength of the magnetic field was 0.45 Tesla. By applying this to the torque equation, the spacing between the plates was 2 mm, and the inner and outer diameters of the plates were selected to be 45 mm and 55 mm, respectively. Overall, this paper proposes an optimal design technique to maximize the performance of an MR multi-plate clutch.

• Journal of the Korean Professional Engineers Association
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• v.28 no.4
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• pp.54-75
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• 1995

This synthesis has been prepared from a review of literature on Truck Escape Ramps technology and a survey of current practice by state department of transportation. Their locations have been determined usually from a combination of accident experience and en-gineering judgement, but new tools are emerging that can identify needs and sites without waiting for catastrophic accidents to happen. The Grade Severity Rating Systems holds promise in this regard. Design Procedures for truck excape ramps continue to evolve. Gravel arrester beds are clearly the preferred choice across the country Rounded aggregate, uniformly graded in the approximate size range of 13 to 18mm. Tech-nical publications typically have dassified TER types as paved gravity, sandpile, and ar-rester bed ramps. The design speed for vehicle entry into the ramp in critical to the deter-mination of ramp length. An escape ramp should be designed for a minimum entry speed of 130km/hr, a 145km/hr design being preferred. The ramps should be straight and their angle to the roadway align-ment should be as possible. The grade of truck escape ramps show the adjustment of ramp design to local topography, such as the tradeoff of ramp length against earthwork requirements. A width of 9 to 12m would more safety acommodate two or more outof con-trol vehicles. Reguarding comments on the most effective material, most respondents cited their own specification or referred to single graded, rounded pea gravel. The consensus essentially Is that single graded, well -rounded gravel is the most desirable material for use in arrester beds. The arrester beds should be constructed with a minimum aggregate depth of 30cm. Successful ramps have used depths between 30 and 90cm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.937-943
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• 2013

An independently driven electric corner module cannot be applied to an actual vehicle without some difficulty, because of vehicle safety problems in the case of malfunctions and degraded ride and handling performance owing to the increase in the unsprung mass. In this study, a simulator is developed to evaluate the vehicle driving performance in order to solve ride and handling problems. Component modeling of a small-sized electric vehicle with an independently driven electric corner module is performed using MATLAB/Simulink. The vehicle is modeled by using CarSim, which can be used to analyze the vehicle maneuvers with 27 DOFs. The control algorithm for the improvement of vehicle driving safety and ride and handling performance is validated by using the developed simulator.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.30.1-30.1
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• 2018

일제 강점기를 지난 후 광복을 맞았지만, 전란의 폐허 속에 개설된 대학의 천문학과의 관측 시설들은 전문한 상태였다. 필자가 학부 재학 중이던 6-70년대까지도 시 시공(時空)의 흐름은 필요한 것을 직접 만들어 사용할 수밖에 없는 시대로 몰아가고 있었다. 당시를 회고 하며 지금까지 걸어 온 "천문기기 제작 연구의 삶"을 회고하고자 한다. 대학 재학 시절 교수님의 도움으로 막스토브 망원경을 제작하고, 40cm 카세그레인 망원경 등 광학계의 원리와 특성연구를 통해 부품 조립을 수행할 수 있었다. 태양 흑점관측을 위한 10cm 굴절 망원경의 투영시설을 고안하여 6개월 동안 관측하였지만. 석사 논문을 위해 광전측광 관측시스템을 제작하여 식쌍성 관측을 수행하였다. 그 결과 한국의 시설로 UBV 광도곡선 완성하여 1975년 가을 천문학회에서 발표하였다. 1976년 2월 국립천문대 천문계산연구실에 발령 받고 역서편찬 업무를 담당하면서 소백산 60cm 망원경 최종 설치를 끝내고, 천문대(현 역삼동 과총회관 빌딩) 옥상에 2m 규모의 목재 돔을 설계 제작하고 일반인들을 위한 대중천문 활동을 시작하였다. 재직 중에 항상 한국의 열악한 천문시설의 상황을 실감하고 20대를 마감하면서 퇴직하여 "한국천문기기 연구소"라는 명칭으로 천체 돔을 설계하고, 돔 제작기계를 개발하였다. 망원경만 보관 중인 국내 4개 대학에 돔을 납품 한 후 연세대학교 천문대의 직경 6m 스텐레스 돔을 제작하였다. 아울러 연세대 천문대 60cm망원경을 설치하면서 이 곳에 입사하여 관측 장비개발 연구와 관측에 전념하게 되었다. 재직 기간 중 대학의 배려로 카나다 국립천문대(DAO) 방문연구원으로 1.8m 망원경으로 식쌍성들의 분광관측을 수행하여 시선속도곡선을 완성하였고, 체류 중에 스텝들과 국내에서 사용할 60cm용 첨단 분광기를 설계하였으나 대학에 재원이 없어 제작을 못한 아쉬움이 남는다. 1989년 2월 충북대학교 천문우주학과에 부임하면서 열악한 상황이지만 교육과 연구 장비로 20cm와 35cm 소형 망원경의 디지털 광전측광시스템으로 간이 천문대를 설치하여 운영하였다. 학과 설립 10 주년(1998년)을 맞아 40cm 망원경과 6m 돔을 설치하여 교내천문대가 완공되었다. 2000년이 되면서 대중 천문활동 을 위해 이동 천문대를 제작하여 4륜 자동차에 견인하여 여러 지역을 찾아 관측과 강연 활동 등 학과의 대중천문 활동의 특성을 살리는 계기를 만들게 되었다. 학과 설립 20주년(2008년)을 맞으면서 충북 진천에 16개 자동분할 개폐식 스릿의 9m 돔 안에 1m 망원경을 원격관측 시설을 완비하여 대학 본부의 기관으로 충북대학교천문대를 개관하고 관측시설을 완비하였다. 우리의 전통적인 세종시대 천문시설은 당대 최대의 시설이지만 당시 유물들이 모두 소실되어 현존하는 것이 하나도 없음은 실로 아쉬움이 큰 것이었다. 누군가는 그 구조, 형태, 원리, 기능, 사용방법 등을 밝히고 복원을 시도해야 할 시급함이 있었다. 문헌을 통해 1991년부터 학부졸업 논문으로 "고천문 의기(儀器) 복원연구" 분야의 발표를 시작하였다. 그 결과를 통해 세종탄신일에 영릉에서 숭모제 행사 후 그 곳에서 수년간 세종시대 고천문의기 한가지씩 작동모델을 복원하여 제막식을 거행하였다, 유물복원 회사 (주)옛기술과 문화 와 함께 팀을 이루어 매년 제작할 종목을 준비하게 되었다. 간의(簡儀)를 복원한 후에는 일성정시의, 소간의, 앙부일구, 정남일구, 석각천문도, 혼천의, 혼상, 각종 해시계 등 매년 지속적으로 복원되어 큰 규모의 야외 전시장이 완성되었다. 작동모델 설계연구팀의 자문과 제작팀과의 팀웍으로 이룬 성과인 것이다. 한번 시작품이 발표된 모델들은 국내 과학관과 박물관, 천문관에서 후속 모델을 설치하였다. 한국천문연구원과 부산 동래읍성 내에 장영실 과학 동산은 간의와 혼상을 비롯한 각종 해시계들을 설치한 큰 규모의 야외 전시장이다. 조선의 명망 높은 유학자들이 인격적인 하늘을 살펴보았던 혼천의와 일만원권에 그려 있는 국보 230호 자명종 혼천시계(일만원권의 그림)의 작동 모델을 제작하였다. 이와 같은 연구 결과들은 석사과정 박사과정을 통하여 더 심층적인 연구들이 발표되었고, 각종 조선(한국)의 천문의기(天文儀器) 연구 자료들은 연구팀들을 통해 중국과 일본 등 해외에서도 발표되었다. 지금까지 복원된 유물들이 완성되기까지는 참여한 많은 연구원들과 제작팀들이 합심하여 각자의 역할을 수행하여 최종 작동모델들이 하나 둘 완성되는 것이었다. 이것은 참으로 보람된 일이었고, 은퇴 후 지금은 재능기부자로서 즐거운 삶을 이어 갈수 있게 되었다.