Analysis of Dynamic Characteristics of Clutch-to-Clutch Shifting Control of an Automatic Transmission

The fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes. For this very purpose, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. An impact function can be used to reduce the transmitted torque of the oncoming shift elements before synchronization point in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with parameters well calibrated, engine torque transferring and speed synchronizing process will be smoother, which helps realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.Copyright © 2014 IFSA Publishing, S. L.