• Title/Summary/Keyword: Shift Control Hydraulic Circuit

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Development of the Oil Consumption Rate Test Method and Measurement Data Analysis for an Automatic Transmission System (자동변속기 오일 소요유량 시험법개발 및 측정데이터 분석)

  • Jeong, H.S.;Oh, S.H.;Yi, J.S.;Lim, J.S.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.6 no.1
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    • pp.10-16
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    • 2009
  • Automatic power transmission systems consisted of a torque converter and several planetary gear sets, clutches and brakes are controlled by a hydraulic shift control circuit and an electronic transmission control unit. The hydraulic circuit serves for the operation of the torque converter and lubrication oil supply of the transmission system as well as for the actuation of clutches for the automatic gear shift. The complicated hydraulic control circuit constructed by many spools, solenoids, orifices and flow passages are integrated into one small valve block and it is powered by one hydraulic pump. In this paper, a test equipment was developed to measure the oil consumption of each component at various wide operating conditions. Test data about 730 sets acquired from five test items are analyzed and discussed on the oil capacity of the circuit.

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A Study on Applying the Direct Control Method for Small Forklift Transmission System (직접 제어 방식을 적용한 소형 지게차 변속 시스템에 관한 연구)

  • Jeong, Y.M.;Lim, K.;Yang, S.Y.
    • Journal of Drive and Control
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    • v.10 no.4
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    • pp.34-40
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    • 2013
  • The transmission control method of small forklift is classified into pilot control method and direct control method. In pilot control method, the hydraulic circuit which consists a lot of components is very complex so the production process is too costly and time consuming. The direct control method contains fewer components that can be configured to simple hydraulic circuit. It has more advantages because the shift sensitivity of transmission is changed easily via the input profile. In this paper, the controller design and the input profile for system are studied to apply to the direct control method. The input profile consists of Fill section, Hold section and Ramp section. The characteristic of each section is obtained through experiment. As the result, the shift sensitivity and starting performance are effected by Fill section and Hold section.

A Study on Simulation of Shift Sensitivity of Small Forklift Transmission using Direct Control Method (직접제어 방식을 이용한 소형 지게차 변속감도 시뮬레이션에 관한 연구)

  • Jeong, Y.M.;Yang, S.Y.
    • Journal of Drive and Control
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    • v.11 no.4
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    • pp.8-14
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    • 2014
  • The transmission control method of a small forklift is classified into a pilot control method and a direct control method. In the pilot control method, the complex hydraulic circuit consists of many components, making the production process too costly and time consuming. The direct control method contains fewer components that can be configured to simple hydraulic circuits. As another advantage, the input profile easily changes the shift sensitivity of the transmission. Therefore, this research considers the characteristics of the direct control method in the development of hydraulic system design. This paper will present a simulation of the direct control transmission using AMESim. First, modeling of the direct control method is obtained and simulated with real parameters. The simulation results then are carried out and compared with the experimental results to verify and analyze the characteristics of the direct control method.

Nonlinear Control Design for Reducing Shifting Torque in Automatic Transmission (자동변속기의 과도토크 저감을 위한 비선형 제어기설계)

  • Kim, D.H.;Lee, K.I.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.12
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    • pp.95-104
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    • 1997
  • We consider controller design problem to enhance shift quality for automatic transmission. A dynamic modeling related to shifting (mainly 2-3 up-shift) is constructed and nonlinear robust controllers are designed to reduce output torque during shifting. Suggesting a new hydraulic circuit enabling the direct clutch drive, the control activity is extended and more implementable than the conventional design. The designed robust controllers overcome the unmodeled dynamics and the uncertainty embending in the system. Moreover, the dynamic effect between the clutch pressure and the PWM valve duty is considered via singular perturbation technique.

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Minimization of Shifting Shock of Tractor PST using SimulationX (SimulationX를 이용한 트랙터 PST 변속 충격 최소화 연구)

  • Eom, Tae Ho;Lee, Chul-Hee
    • Journal of Drive and Control
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    • v.15 no.3
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    • pp.36-42
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    • 2018
  • Agricultural tractors require frequent shifting to improve operation efficiency, and PST (Powershift Transmission) is considered as a suitable transmission. However, due to the inherent characteristics of the PST, shocks arise during shifting, which imparts a negative effect on the operator. Therefore, in order to improve the transmission performance of the tractor PST, researches on various methods including the hydraulic system circuit, the engine input speed control, and the mechanical system of the transmission are steadily being conducted. In this study, in order to reduce the impact of PST on a shift based on SimulationX software, we analyzed the characteristics of the input signal of PCV (Pressure Control Valve) through sensitivity analysis and verified the simulation model through actual vehicle test. Optimization was performed for minimizing the shift shock for some of the parameters of the input signal at constant temperature and RPM conditions.

Pressure Control of Lockup Solenoid Valve for Automatic Transmission (자동변속기 록업솔레노이드밸브의 압력제어)

  • Park, Kwan-su-;Chung, Soon-Bae;Lee, Kyo-Il-
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.472-477
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    • 1994
  • The lockup clutch is embeded on torque converter of automatic transmission to prevent the efficiency deterioration of torque converter in high speed. For improving fuel consumption rate, it is desirable to engage the lockup clutch earlier. But, it results in degrading shift quality, due to the transient torque. The transient clutch pressure which affects the shifting quality, should be controlled properly. In this study, to solve the problem, it is analysed the hydraulic circuit of lockup system including line pressure regulating circuit, established the nonlinear model, and designed the PID controller. The line pressure is supplied to the lockup clutch through the lockup control valve by switching the lockup solenoid valve on. In order to control the transient pressure actively, it is needed to control the lockup solenoid valve by closed loop control. The lockup solenoid valve is 2-way on-off valve, and is adequate for PWM control. To reduce the pressure chattering, the carrier frequency is increased. Target pressure profile is computed from optimized velocity difference profile throuth dynamic equation of vehicle system.

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