• International journal of advanced smart convergence
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• 제12권4호
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• pp.451-457
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• 2023

Global warming is causing abnormal climates such as floods, droughts, and typhoons all over the world. According to some scientists, carbon dioxide emitted from automobiles is the main cause of global warming. To cope with this, each country is making efforts to replace the existing fossil fuel-powered engine-driven cars with electric vehicles. In order to commercialize small electric vehicles in Korea, it is necessary to solve many problems such as improvement of hill climbing capacity and improvement of power performance. In this study, we propose a proprietary model for a continuously variable transmission(CVT) of a small electric vehicle that can be operated on hills, in which a spring is mounted on a driving pulley and a driven pulley. A prototype of the CVT model using a spring was manufactured and attached to a small electric vehicle body.

• 한국가스학회지
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• 제28권1호
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• pp.59-64
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• 2024

본 연구에서는 초소형 특수목적형 전기자동차에 적용 가능한 초소형 변속기에 대한 연구를 진행하였다. 일반적으로 전기자동차에서는 다단 기어형태의 변속기를 삭제하고 모터의 출력을 제어하거나 감속기를 통해 초기 구동력을 확보한다. 그러나 전기카트나 경형 전기자동차와 같은 초소형 차량에서는 배터리 용량이 상대적으로 적기 때문에 적재 상태에 따라 주행 거리가 감소하거나 모터에 부하가 가해질 수 있다. 따라서 본 연구에서는 CVT(Continuously Variable Transmission)의 변속 메커니즘을 적용하여, 구배 상태나 적재 상태와 같은 필요한 상황에서 변속이 가능한 고단 0.625와 저단1.6의 기어비를 갖는 2단 구조의 감속기를 개발하였다. 선정된 기어비를 기반으로 변속기를 설계하고, 개발된 변속기의 동력 전달 효율을 검증하기 위해 시험기를 제작하였다. 이 시험기를 통해 변속기의 회전 속도와 부하량을 변화시키며 동력 전달 효율 특성을 확인하고, 변속과 구동 시 발생되는 발열 특성도 확인하였다. 그 결과를 토대로 CVT구조를 갖는 2단 구조의 변속기를 개발하였다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 동계 학술대회 논문집
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• pp.22-27
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• 2000

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 동계 학술대회 논문집
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• pp.28-33
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• 2000

• 제어로봇시스템학회논문지
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• 제11권8호
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• pp.696-703
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• 2005

Since most autonomous mobile robots are powered by a battery, it is important to increase the continuous operating time without recharging. This can be achieved by improving the energy efficiency of a mobile robot, but little research on energy efficiency has been performed. This paper proposes two methods for improving the energy efficiency of an omnidirectional mobile robot.. One method is to realize a continuously variable transmission (CVT) by adopting the mechanism of steerable omnidirectional wheels. The other is the proposed steering algorithm in which wheel arrangement of the mobile robot is continuously adjusted so as to obtain the maximum energy efficiency of the motors during navigation. In addition, new omnidirectional wheels which can be transformed to the conventional wheels depending on the driving conditions are proposed to compensate for less efficient omnidirectional drive mode. Various tests show that motion control of the OMR-SOW works satisfactorily and the proposed steering algorithm for CVT can provide higher energy efficiency than the algorithm using a fixed steering angle. In addition, it is shown that the differential drive mode can give better energy efficiency than the omnidirectional drive mode.

• Journal of Advanced Marine Engineering and Technology
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• 제30권8호
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• pp.863-869
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• 2006

A new CVT, the inner spherical traction CVT (ISCVT) is introduced. Transmission of the most scooters is the self-controlled variable pulley-belt type of CVT having some disadvantages in the fuel consumption and the limitation of the transmittable power due to the slippage between the belt and pulley. Unlike this, ISCVT controlled directly by driver is more efficient and the contact mechanism having the same line of contact normal of the spherical rotors of different radii on common center causes that the power density and torque capacity are remarkably improved. The prototype with the specifications of 50cc scooter is designed and tested.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1067-1068
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• 2013

• 오토저널
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• 제9권3호
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• pp.1-9
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• 1987

자동차용 CVT로서 여러 가지 장치가 연구되고 있으나 크게 나누어 다음의 5가지, 1)유압식 변속 기(hydrostatic transmission), 2)오버런닝 클러치(overrunning clutch CVT), 3) 전기식 CVT, 4)미 끄럼 클러치식 치차변속기(multispeed gearbox CVT with shipping clutch), 5)트랙션 전달장치(t raction drive)로 볼 수 있다. 이중 지금까지 자동차에 실제 적용되어 가장 큰 가능성을 보인 것 은 트랙션 전달장치 뿐이다. 따라서 본문에서는 1)-4)의 4가지 형태의 CVT에 대하여 간단히 서 술하고 트랙션 전달장치를 중심으로 설명하기로 한다.

• International Journal of Automotive Technology
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• 제1권1호
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• pp.42-47
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• 2000

This paper concentrates on the design and construction aspects of a transmission for a mid-class passenger car with internal combustion engine. The transmission, consisting of a Continuously Variable Transmission (CVT) with a Van Doorne V-belt, a planetary gear set and a compact steel flywheel is used to prove the concept of mechanical torque assist. The design goal is to obtain a proof of concept transmission with maximal efficiency, using proven transmission technology. With the developed so called Zero Inertia CVT, the fuel economy of the car is improved by operating the engine at its fuel optimal operating line. To achieve a good vehicle acceleration response, the flywheel assists the powertrain mechanically.

• International Journal of Automotive Technology
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• 제7권7호
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• pp.785-793
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• 2006

The topic of this study is the control strategy of a mild hybrid electric vehicle (HEV) equipped with a continuously variable transmission (CVT). A brief powertrain and vehicle configuration is introduced followed by the control strategy of the HEV with emphasis on two key parts. One of them is an ideal operating surface (IOS) that operates the CVT powertrain optimally from the viewpoint of the tank-to-wheel efficiency. The other is a charge sustaining energy management to maintain the battery state of charge (SOC) within an appropriate level. The fuel economy simulation results of the HEV over standard driving cycles were compared with those of the baseline vehicle. Depending on the driving cycle, 1.3-20% fuel saving potential is predicted by the mild hybridisation using an integrated starter alternator (ISA). The detailed energy flow analysis shows that the majority of the improvement comes from the idle stop function and the benefits for electrical accessories. Additionally, the differences between the initial and the final SOC are in the range $-1.0{\sim}+3.8%$ in the examined cycle.