Abstract
Vehicles equipped with Automated Manual Transmissions (AMT) for gear shift control show many advantages in terms of reduction of fuel consumption and improvement of driving comfort and shifting quality. In order to increase both performance and efficiency, an important target is focused on the minimization of the typical torque interruption during the gear shift, especially in front of the conventional automatic transmission. Recently, AMT are proposed to be connected with planetary gears and friction brakes, in order to reduce the torque gap during the gear change process. This paper is focused on a block-oriented simulation methodology developed in Matlab/Simulink/ Stateflow environment, able to simulate the performance of a complete FWD powertrain and in particular to predict dynamic performance and overall efficiency of the AMT with innovative Torque Gap Filler devices (TGF). A comparison between traditional Manual Transmission (MT) system and AMT with TGF device is presented, focusing in particular on the gear shift control strategies able to improve the performance of these systems. Some dynamic simulations are discussed in order to validate the proposed model and to simulate performance and limitations of this mechanical solution. Copyright © 2008 SAE International.