Abstract
The application of an Automated Manual Transmission (AMT) and steering wheel control paddles to a production car was pioneered by
Ferrari in 1997 with its F355-F1 model. The benefits for the driver are an ease of use and an increase in safety, making it possible to change gear ratios without taking the hands off the steering wheel.
Moreover, with respect to even the latest Automatic
Transmissions (AT), an AMT provides better performances and lower fuel consumption and emissions due to the higher mechanical efficiency.
Another characteristics of the AMT is to present a torque interruption which (even though it is faster than a Manual Transmission) could be perceived a
stagnation time by the driver. In fact, he have just to pull the paddle (which could be accomplished in a few milliseconds) and then expects an immediate gearshift. On the other hand, it is well known that an AT is characterised by an almost constant torque during the gearshift, leading to lower performances, higher fuel consumption and emissions, while providing a good comfort level.
The objective of the work was the elimination of the torque interruption. The idea which led the project, derived from the Formula 1 experience, was to make the torque interruption fast enough in order to be practically negligible. The work presented in this paper was done with the aim to develop a new
AMT configuration which could provide a good level of comfort (comparable with that of an AT) together with outstanding performance and retaining a good overall mechanical efficiency.
Theory (ISO 2631) is unclear in the field of transient accelerations, therefore, a specific experimental program was done. Using vehicle accelerations measurements during gearshift and gearshift-like manoeuvres and driver evaluations a correlation between the objective and subjective results was made. In addition, a specific research program was done using laboratory simulations.
This paper addresses the theoretical base upon which the comfort issues were evaluated, the experimental set-up and the results of the experiments, together with the conclusions in terms of target setting for the development of the transmission.