• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1768-1771
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• 2002

Automatic Transmission System(ATS) was designed to replace the human's manual operation of the gear box. So far, this system operates with the fixed shift pattern information. In this paper, new algorithm considering driver's operation tendency is proposed. Also, to get rid of the uselessly frequent shift of the ATS, the conditions and the status of the vehicle would be included for the evaluation in making a decision of shifting. A field test is done in a car equipped with the computer set connected to Transmission Control Units(TCU) to check the status of the test car, and it shows the excellency of the proposed algorithm.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2348-2351
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• 2000

In order to operate SI(Spark Ignition) engine at the optimal fuel efficiency, it is necessary to use continuously variable transmission(CVT) which has more excellent fuel consumption property than transmissions of gear box types commonly used. This study introduces new type of nonlinear control approach to control precisely CVT including nonlinear characteristics. The nonlinear controller is basically composed of input-state feedback linearization, which can cancel the nonlinearities included in CVT on specific controllable area, and sliding-mode control. In this paper, good control performance of contrtol system with the nonlinear controller is confirmed with computer simulations.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.311-312
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• 2002

Friction losses in complex tribo-technical system are revealed primarily through their effect on the operating temperature level. In order to assess the influence of the oil formulation on the temperature level comprehensive tests were run in a model test apparatus consisting of a special adapter for the 4-ball test rig. More than ten with different formulations (different base oils, additive packages and viscosity modifiers) were tested, The resulting temperature levels varied by nearly 25 %. The objective of this model testing is to assess the influence of the oil formulation on the operating temperature of vehicle manual transmission. The correlation to the real tribotechnical system was confirmed by a VW Polo transmission test.

• Journal of Biosystems Engineering
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• v.36 no.4
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• pp.243-251
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• 2011

Purpose of this study was to analyze power requirement of an agricultural tractor for baler operation. First, a power measurement system was developed and installed in a 75 kW agricultural tractor. Strain-gages with a telemetry system were used to measure torques of transmission and PTO input shafts. An engine tachometer was used to measure rotational speed of transmission and PTO input shafts. The measurement system also included pressure sensors to measure pressure of hydraulic pumps, an I/O interface to acquire the sensor signals, and an embedded system to determine power requirements. Second, field experiments were conducted at two PTO speed levels, and proportion of utilization ratio of rated engine power and power consumption of major parts (transmission input shaft, PTO input shaft, main hydraulic pump, and auxiliary hydraulic pump) were analyzed. Results of usage proportion of engine power for PTO speed level 1 and 2 were 4.1 and 2.2%, 31.5 and 16.3%, 49.6 and 59.7%, 14.4 and 20.8%, and 0.4 and 1.0%, respectively, for ratio of measured engine power to rated engine power of less than 25%, 25 ~ 50%, 50 ~ 75%, 75 ~ 100%, and greater than 100%. The results showed that the usage proportion increased in the range with the ratio of power requirement to rated engine power of over than 50% when the PTO gear was shifted from P1 to P2. Averaged engine power requirement for baling operation, tying and discharging operation, and total operation were 43.3, 37.3, and 42.0 kW and 49.0, 37.0, and 47.4 kW, respectively, for PTO speed level 1 and 2. Paired t-test showed significant difference in power consumption of engine, transmission input shaft, and PTO input shaft for different PTO speed levels. Therefore, the power consumption of engine for baler operation increased when the PTO gear was shifted from P1 to P2. It was indicated that the power requirement of tractor was affected by the PTO rotational speed for baler operation.

• Journal of the Korean Society of Safety
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• v.22 no.5
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• pp.1-6
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• 2007

Vibro-impacts in manual transmissions result due to several nonlinearities such as multi-staged clutch characteristics and gear backlashes. For the sake of understanding the torsional system, one specific manual transmission with front engine and front wheel drive configuration is investigated with a linear model under the several assumptions substituting the nonlinear factors. First, this system is examined with the mathematical approaches by expressing the governing equations to find out the torsional motions. Second, this system is analyzed using the linear model in order to understand its modal and frequency response characteristics using eigensolution method and the FRF(Frequency Responses Function) analysis. Third, with the given results from the eigensolutions, several mode shapes are investigated related to the torsional motion characteristics. Fourth, the system characteristics with the FRFs are studied with the basic approach, with which the several key parameters will be suggested based upon the results in the further studies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.11
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• pp.2817-2824
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• 1994

A torque split type multi-pass CVT(MPC) system consiting of CVT and planetary gear train with 4 clutches was suggested to overcome the inherent inferior acceleration performance of CVT. Also, a shifting algorithm of MPC was suggested for the two driving modes : (1) power mode and (2) economy mode. By using the shifting algorithm and the MPC vehicle dynamic model, numerical simulations were performed to estimate the performance of the MPC vehicle. Simulation results showed that comparing the performance of the conventional 4-speed automatic transmission, an improvement in acceleration can be obtained by MPC for the power mode and 31% improvement in fuel economy for the economy mode.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.3
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• pp.40-46
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• 2021

An automatic transmission of automobiles enables comfortable driving experience with lower transmission shifting jerks. However, the assembly structure is more complicated and requires additional components with lower efficiency than the manual transmission system. Extensive research has been conducted to improve the overall transmission efficiency by optimizing each component of the automatic transmission assembly. This study focuses on enhancing the friction torque of double angular contact ball bearings used in automatic transmission. The friction torque of the bearing varies with the operating conditions such as the operational load and rotating speed. Since reducing the friction torque of the bearing tends to deteriorate the durability of the bearing, it is necessary to design the bearing having a minimum required friction torque by determining the durability life of an automatic transmission assembly, In this study, the theoretical life and friction torque of conventional and newly-developed bearings are calculated. The difference in the friction torque between the new and existing bearings are also evaluated.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.1
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• pp.163-181
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• 1998

In this study, the objective is determine the optimal design variable of engine mount system using the rubber mount of bush-type which is usually utilized in passive control to minimize vibrations of vehicle body or transmission from engine into body. The engine model adopted in this study is 4-cylinder, 4-stroke gasoline engine support- ed by 4-points. The system is modelled in 10 d.o.f.-rigid body motion of the engine & transmission in 6 d.o.f., elastic motion of vehicle body in 4 d.o.f.(1st torsional, 1st vertical and 1st & 2nd lateral bending vibration mode). To consider the elastic motion of vehicle body, find the eigenvalues and mode shapes of vehicle body by nodal testing and then determine the modal masses and stiffnesses of the body. The design variables of the engine mount system are locations, stiffness and damping coefficients of the rubber mounts(28 design variables). In case of considering the torque-roll axis for the engine, the design variables of the mount system are reduced to 22 design variables. The objective functions in optimal design process are considered by three cases, that is, 1) transmitted forces through engine mounts, 2) acceleration components of generalized coordinates for the vibration of vehicle body, 3) acceleration of specified location(where gear box) of body. three case are analyzed and compared with each other.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.6
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• pp.675-681
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• 2015

When many holes on a plane are machined simultaneously, the positional precision and machining efficiency are very important. Multi-spindle heads are typical order making products of which the number of shafts and hole positions vary depending on the size or form of the product. For the automatic design of multi-spindle heads, the design modules for power transmission systems for drive, idle, and spindle shafts were developed, and a design technique the determining the optimum position and number of idle shafts according to gear positions was developed. In addition, for the precise determination of the multi-spindle head, the design methods for the guide planes of columns, and feed mechanisms were devised. In addition, the design modules for accurate clamping and automatic transportation mechanisms were developed. Finally, in order to simplify and standardize the design process, the design analysis and simulation verification modules are integrated.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.1
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• pp.14-17
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• 2009

In this paper, A generator of existing vertical type wind turbine system is connected to bevel gear. But, the generator of proposed wind turbine system is connected to Hydraulic torque converter. In case of the proposed wind turbine system, is possible to make torque transmission long distance, set up generator somewhere in between the tower or the ground as well as, nacelle weight can be greatly down. Lightweight of nacelle exactly wind direction tracking can be easily also, cost down of established frame structure and generator setting, maintenance, easy and improvement of system stability.