• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.24-34
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• 2019

An automotive automatic transmission is a popular power-transmitting device in passenger vehicles, as it provides various speed ratios for diverse driving conditions with easy manipulation and smooth gear shifting. The transmission is mainly composed of input and output shafts, planetary gear sets, brakes/clutches, and housing, and it yields multiple forward gears and one reverse gear by actuating the shifting devices of the brakes and clutches. In developing a new transmission, kinematic configurations of a transmission, which presents a brief structure and actuation schemes for speed ratios, need to be checked to determine if the structure can be assembled in a layout. It is impossible for a transmission concept having any interference in connecting main components to be developed further in the design process, since connection interference leads to failure of a layout design in the 2-D plane. In this research, an analysis of the assemblability of a front-wheel drive automatic transmission is carried out on an example concept design by applying the vertex addition algorithm based on graph theory.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.271-272
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.208.1-212
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• 1997

In this paper, a computer simulation tool for evaluting integrated engine/transmission control system using MATLAB/SIMULINK is investigated. Since a modular programming technique based upon the object-oriented programming is used in the paper, the simulation tool developed reduces the burden of model complexity by dividing engine/transmission systems into hierarchical subsystem. Furthermore, it also provides user -friendly, reusable, and upgradable characteristics of the system. The simulation tool could be useful to the automotive engineers who frequently change models and develop new systems in the automotive powertrain and control area.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.3
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.75-81
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• 1999

In this paper, the details of electronically controlled CVT is described , which Kia Motor company recently developed in prototype form for hybrid passenger car. This transmission has two input shafts, one for engine and the other for traction motor. The shaft for traction motor is located at rear side which is extended from primary pulley shaft and connected to traction motor through adapter gear box. Adopting two input system, various driving mode is available such as motor alone driving in hybrid vehicle application. As far as electrohydraulic system concerned , this transmission uses two bleed type variable force solenoids for line pressure and ratio control, and one on-off solenoid for clutch control. Another feature for this transmission is that oil pump for transmission is separate from CVT for supplying oil pressure even at vehicle standstill.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.68-84
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• 2000

A study to reduce the transient torque in shifting in automatic transmission has been very important issue. Recently it is really dominant to decrease the torque by using independent-acting hydraulic circuit because we can control the clutch pressure actively and elaborately. So we design the new hydraulic circuit to control the clutches in automatic transmission and make the module library of computer simulations, We apply the results to GM model automatic transmission and carry out 1longrightarrow4 shifting simulations. By this work we recognize the capability of active and elaborate clutch pressure control using new hydraulic circuit. In addition We develop the tool to simulate the powertrain system. It is easier to update and exchange the subsystem model or parameters than conventional simulation tools.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.54-66
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• 1998

In a passenger car automatic transmission, the gear ratio is determined by the combination of clutches and brakes, and each element of th planetary gear set is rotated or held stationary by the action of them. In this study, to investigate the shift characteristics of automatic transmission, the equations of motion are derived from the dynamic model of Ravigneaux type planetary gear set and solved analytically. The shift characteristics of each element of planetary gera set during gear ratio change are investigated by considering the torques and velocities of input, reaction and output elements.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.36-46
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• 1993

In CVT vehicle, the engine speed is completely decoupled from the vehicle speed within the range from maximum transmission ratio to minimum transmission ratio. This allows the engine to operate in optimal state(e.g. best fuel economy or maximum power mode.) In this study, the CVT control algorithm for optimal operation of engine is suggested. In order to implement the real time digital control of electro-hydraulic CVT system, a software called CVTCON has been developed. CVTCON also includes the CVT operation module, (2) system test module, (3) system control module and (4) data management module. By using the CVTCON and the electro-hydraulic CVT system, two modes of experiments were carried out: constant throttle opening mode and acceleration mode. From the experimental result, it was found that the algorithm suggested in this study showed optimal operation of the CVT system.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.3
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• pp.218-226
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• 2002

This study was carried out to develop continuously variable-speed transmission(CVT) fur an agricultural tractor. The full-toroidal variator mechanism with flour discs and six rollers was utilized as a device fur changing speed ratio continuously. In system layout design, the sizes of the roller cylinders and the end-load cylinder, which were critical factors for controlling the variator, were designed. The planetary gear unit and six pairs of the gear assemblies were designed to establish the maximum speed of the vehicle at 30 ㎞/hr. In addition, the hydraulic clutch, the silent chain, the hydraulic manifold and the electronic controller were designed. Based on the design, a prototype CVT was developed and tested. Test results show that the CVT developed in this study could successfully provide variable speed of the tractor.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.771-780
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• 2007

In recent studies, various types of multi mode electric variable transmissions of hybrid electric vehicles have been proposed. Multi mode electric variable transmission consists of two or more different types of planetary gear hybrid powertrain system(PGHP), which can change its power flow type by means of clutches for improving transmission efficiencies. Generally, the power flows can be classified into three different types such as input split, output split and compound split. In this study, we analyzed power transmission characteristics of the possible six input split systems, and found the suitable system for single or multi mode hybrid powertrain. The input split system used in PRIUS is identified as a best system for single mode, and moreover we identified some suitable systems for dual mode.