Hybridization of the power-train is one of the solutions which all the major car manufacturers are developing to reduce fuel consumption, CO_2 and engine gas emissions. In parallel HEVs, both an electric drive and the conventional internal combustion engine (ICE) provide driving torque to the wheels either separately or together. During the coast-down and breaking operations the electric drive also can recover a fraction of the kinetic energy, otherwise dissipated, that the vehicle makes available in these phases, with advantages in terms of overall vehicle efficiency. Unlike pure electric vehicle (EV) and series hybrid electric vehicle (SHEV), where the whole vehicle kinetic energy during decelerating operations might be captured by the electric drive directly arranged on the driveline, in parallel architectures the internal combustion engine losses decrease significantly this chance of save energy. To take full advantage of PHEV configurations equipped with Automated Manual Transmission (AMT) systems, the control strategy for gear shifting in vehicle deceleration have to take account of the drag torque map of the internal combustion engine. In this paper a regenerative braking gear shifting and clutching strategy for PHEVs equipped with AMT is presented. Calculation and simulation are developed by means vehicle and engine testing results, realistic set of parameters of the transmission and dynamic performance indexes available in literature have also been considered. Thanks to an appropriate gear ratios sequence automatically selected matched to an integrated control of the electric drive it's possible to cut up to fifty percent of engine losses with a remarkable improvement of energy recovered in this phases.
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