• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.2
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• pp.7-20
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• 2007

TCU is a shift controller far automatic transmission of which major functions are to determine the shift point and manage the shifting process based on the various input signals. As the recent digital control technologies advance, it plays a key-role to improve a transmission performance and its algorithm becomes more complicated. This paper describes the development of transmission simulator fur wheel loader that enables a TCU for normal stand-alone operation by the real-time emulation of TCU interface signals. It can be utilized for the analysis of shift control algorithm implemented in a commercial TCU as well as for the development of brand new TCU.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.07a
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• pp.66-71
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• 2002

파워시프트는 동력전달의 단속 없이 변속할 수 있는 변속 방식이다. 기어는 동기 물림식으로 되어 있으며, 유압 클러치를 통하여 주행 중에도 동력의 흐름을 제어할 수 있다. 주요 구성 요소는 동력 흐름을 제어할 수 있는 유압 클러치와 동력을 전달하는 기어 조합이며, 유압 클러치는 피스톤, 리턴 스프링, 디스크, 플레이트 등으로 구성되어 있다. 접속 시에는 유압 피스톤이 리턴 스프링을 압축하며 전진하여 플레이트와 디스크에 수직력을 가하고 이를 결합시켜 동력을 전달한다. 해제 시에는 리턴 스프링에 의하여 피스톤이 후퇴하고 동력이 차단된다. 이때 유압 제어 시스템은 최대 견인 부하에서도 변속을 원활하게 하기 위하여, 클러치 압력을 이용해 변속 중 작동 클러치의 토크를 정교하게 제어한다. (중략)

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.3
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• pp.654-662
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• 1998

Shift quality of an automatic transmission in a vehicle is mainly affected by transient pressures in the hydraulic system during shifting. In this study, dynamic modelings of the hydraulic system and the power train of an automatic transmission are made systematically by a bond-graph method. The dynamic characteristics of the line pressures and clutch/brake pressures during shiftings are investigated by simulations and verified by experiments. The effects of clutch/brake pressures on the shift torque are also investigated through driving simulation.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.181-202
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• 2003

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.143-151
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• 2001

During the past several years, the major interests of car manufacturers in development of automatic transmission were in durability and shift quality. However, a large number of researches for improving shift quality that are based on dynamic characteristics of shifting mechanism have been rarely adopted in the developing process because it is quite difficult to predict the shifting performance from the dynamics simulation. One of the important reasons for the difference between simulation results and experiments arises from the automatic transmission hydraulic system that consists of many valves with high order model and shows a lot different dynamics to temperature variation. In this work, hardware-in-the-loop simulation system for automatic transmission was developed f3r improving the accuracy of simulated result by combining the real-time simulation model with the real hydraulic system. The real-time simulation for automatic transmission model excluding hydraulic system is executed with TI's TMS320C31 DSP and the interfacing board which includes 12bit A/D, PWM signal generator and driver, serial driver ,etc is designed for acquiring the simulation data and signal interface with hydraulic system. We verified the proper operation and correctness of shifting result by comparing the off-line simulation result with that of HILS and experimental result which was performed on transmission dynamometer driven by electric motor.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.41-46
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• 2007

This article deals with the design and prototyping of Shift-By-Wire system for an automatic transmission equipped vehicle. In order to manipulate the shifting action electronically, Shift-By-Wire system consists of an electronic shift lever, an electric shift actuator and position sensors. The shift lever is designed to transform the driver's shifting command into an electric signal; it includes the position sensor using non-contact type hall sensor and an additional shifting switch acting as Tip-tronic. For the design of an electric shifting actuator, we investigated the stroke angles and shifting efforts of the manual control lever in each shifting section. And the position sensor of the shifting actuator is designed by using a potentiometer with an optical encoder. Finally the prototype of Shift-By-Wire system was built in a conventional 2.4L class SUV vehicle, and we performed road tests in order to verify its performance.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.1078-1082
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• 1996

기계적 구동장치와 연계된 메카트로닉스 시스템에 대한 개발 시험은 비용, 공간 및 시간 등의 측면에서 제약을 받는다. 이러한 제약은 에뮬레이터를 이용한 개발 과정을 통해서 개선의 효과를 얻을 수 있다. 본 연구에서 설계 제작된 에뮬레이터는 전자 제어식 변속기에 적용된 장치로서 기계적 메카니즘 없이 전자 제어 메카니즘을 완전하게 에뮬레이션 할 수 있는 가능성을 보여준 것이다. 이러한 에뮬레이터를 이용하여 전자 제어장치의 개발 기간을 단축시키고 문제점을 빠르게 찾아낼 수 있다. 에뮬레이터의 개발은 수학적 모델링에 의해서, 장치에 대한 검증은 실차 시험을 통해 얻을 결과와 비교하여 수행된다.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.157-163
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• 2006

A modified ratio control algorithm is proposed for the improvement of the fuel economy for a metal belt CVT. In the modified ratio control algorithm, the CVT ratio is controlled to operate the engine on the optimal operation region which provides the best efficiency from the view point of the overall efficiency of the engine-CVT system. In order to construct the modified ratio map, the CVT system loss model is used by assuming that the all the loss is attributed to the torque loss. It is found from the simulation results that the fuel economy by the modified ratio control algorithm is improved by 5.5 percents compared with the existing ratio control.

• 유공압시스템학회:학술대회논문집
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• 2010.06a
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• pp.56-61
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• 2010

Simulator is a development equipment which enables the ECU to operate in normal mode by simulating the interface signal between ECU and mechanical system electrically. Embedded simulator means simulation function is embedded in ECU firmware, hence the electrical signal interface is replaced by the substitution of information at system program level. This paper explains the development of embedded transmission simulator for the verification of TCU firmware function which covers shifting control and on-board diagnosis. The embedded simulation program is executed in TCU processor along with the TCU firmware and it provides TCU firmware with not only the speed information those are appropriate both in driving and shifting conditions, but also the fault detection signals. Experimental results show that the validity of embedded simulator and its usefulness to the TCU firmware development and verification.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.141-144
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• 1996