SAE 2009-01-0952 : 2009

One of the most significant tasks in automotive design is related to the implementation of gearboxes capable of reducing the torque gap during the gearshift process and, at the same time, not decreasing vehicle performance from the point of view of driveline efficiency. Automated gearboxes based on torque converters ([ 1 ], [ 2 ]) satisfy the first requirement but not the second. On the other hand, manual automated gearboxes ([ 3 ], [ 4 ], [ 5 ], [ 6 ]) satisfy the requirements in terms of consumption, due to the absence of the dissipations caused by the torque converter. In fact, they consist of the basic layout of a manual transmission with hydraulic or electromechanical actuators which are adopted for the clutch and the synchronizers. However, automated manual transmissions cannot guarantee optimal longitudinal dynamics of the vehicle due to the discontinuity in torque transmission when the clutch is disengaged. New solutions are based on the adoption of Dual Clutch systems ([ 7 ], [ 8 ], [ 9 ]) characterized by a significant mechanical complexity. This paper presents, from the points of view of basic concepts and vehicle dynamics simulation, the Torque Gap Filler, a new system patented by the author ([ 10 ], [ 11 ]) capable of joining the advantages of the systems described in [ 1 ] - [ 9 ] without their disadvantages. First of all, the basic concepts of the system are described in detail. Then the basic equations necessary for the development of the control algorithm of the system are presented, and finally a discussion about the possible benefits of the system for two different mechanical layouts are discussed.

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