The main benefits of dual clutch transmissions (DCTs) are: (i) a higher energy efficiencyudthan automatic transmission systems with torque converters; and (ii) the capability to fill the torqueudgap during gear shifts to allow seamless longitudinal acceleration profiles. Therefore, DCTs are viableudalternatives to automated manual transmissions (AMTs). For vehicles equipped with engines thatudcan generate considerable torque, large clutch-slip energy losses occur during power-on gear shiftsudand, as a result, DCTs need wet clutches for effective heat dissipation. This requirement substantiallyudreduces DCT efficiency because of the churning and ancillary power dissipations associated withudthe wet clutch pack. To the knowledge of the authors, this study is the first to analyse the detailedudpower loss contributions of a DCT with wet clutches, and their relative significance along a set ofuddriving cycles. Based on these results, a novel hybridised AMT (HAMT) with a single dry clutchudand an electric motor is proposed for the same vehicle. The HAMT architecture combines the highudmechanical efficiency typical of AMTs with a single dry clutch, with the torque-fill capability andudoperational flexibility allowed by the electric motor. The measured efficiency maps of a case studyudDCT and HAMT are compared. This is then complemented by the analysis of the respective fueludconsumption along the driving cycles, which is simulated with an experimentally validated vehicleudmodel. In its internal combustion engine mode, the HAMT reduces fuel consumption by >9% withudrespect to the DCT.
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