Automated Manual Transmission with Torque Assist Mechanism for Reducing Shift Shock

We have developed a new automated manual transmission (AMT) system that improves gear shifting quality. This AMT can be constructed by adding a torque-assist mechanism that uses a wet clutch to the transmission case of an ordinary manual transmission. This torque-assist mechanism provides a bypass torque that prevents interruption of the wheels torque during shifting. We call this new transmission a torque-assist AMT.

The first characteristic of the torque-assist AMT is to be able to shift gears smoothly, without interrupting the driving force. The second is the quick response of the shifting operation. The third is the AMT's compact structure, and the fourth is the low cost, because the torque-assist mechanism is simply attached to a manual transmission.

We confirmed superior shifting characteristics by performing measurements on a prototype car that had a 1.2 L engine. Shifting without torque interruption was possible in up shift or down shift under acceleration conditions, and a rapid response was obtained in the kick down shift especially. The shifting principle, mechanism, actuators and experiments used to test the AMT are described in this paper.