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This paper presents the methodology adopted by Politecnico di Torino Vehicle Dynamics Research Team to obtain objective indices for the evaluation of the comfort during the gear change process. Some test drivers and different passengers traveled on a test vehicle and assigned marks on the basis of their subjective feeling of comfort during the gearshifts. The comparison between the most significant subjective evaluations and the experimental values obtained by the instruments located on the vehicle is presented. As a consequence, some indices (based on physical parameters) to evaluate the efficiency and the comfort of the gearshift process are obtained. They are in good agreement with the subjective evaluations of the drivers and the passengers. The second part of the paper presents a driveline and vehicle model which was conceived to reproduce the phenomena experimented on the vehicle. The experimental validation of the model is presented.

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).