• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.4742-4748
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• 2014

A semi-automatic clutch was developed for drivers of vehicles with manual transmission. The clutch is operated by pressing a switch on the gear stick without stepping on a clutch pedal when the driver wants to shift gears. To automatic control a clutch, driving information is provided by sensors installed under the vehicle. On the other hand, sensors are prone to failure under severe driving conditions and a long time is needed to install or repair these sensors in the vehicle. In this paper, a semi-automatic clutch that received driving information by CAN communication from the ECU was developed and a pneumatic actuator was used to operate the clutch. The semi-automatic clutch by a pneumatic cylinder was operated with a supply air pressure of more than 3bar.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.3
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• pp.605-614
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• 1995

In the automatic transmission using planetary gear there exists nonlinearities due to the finite difference between gear ratios, which yield torque hole during shift and influence on the ride quality and life of clutch. Based on the reaction carrier and converter turbine speed sliding functions are defined. Nonlinear closed-loop control laws are derived using them. Computer simulation shows that the closed loop design is better than the open loop design and semi-closed loop design.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.3
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• pp.10-21
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• 1996

In this study, as a strategy to improve shift characteristics, the authors developed a new style pressure modulator which can reduce shock torque during power shift by modulating the pattern of pressure increase in the cylinder for actuating the clutch. The remarkable merits of this new pressure modulator lie in its structural simplicity and durability, because the modulator is only composed of a poppet type valve and a few orifices. The usefulness of the new pressure modulator is confirmed by experiments and numerical analyses on a clutch control hydraulic system simplified for easy test. Also, the excellency of the transmission with the new pressure modulator is verified by experiments on a test bench for simulating the running power train of an excavator.