CONTROL STRATEGIES FOR HYBRID ELECTRIC POWERTRAIN CONFIGURATIONS WITH A BALL VARIATOR

摘要

Regular torque split planetary gear trains for automotive hybrid powertrains are limited by the fixed ratio of the planetary gear train. A powertrain incorporating a continuously variable transmission using a torque split with variable ratios enables the powertrain to use the ideal operating lines (IOL) of the engine, electric motor-generator along with the high voltage battery charge/discharge paths, depending upon the mode of operation (charge sustain or charge deplete modes) of the hybrid powertrain. A powertrain further equipped with a hybrid supervisory controller that chooses the torque split and path of highest efficiency from engine to wheel, optionally operate at the best potential overall efficiency point in any mode and also provide torque variability, thereby leading to the best combination of powertrain performance and fuel efficiency. Embodiments of powertrain configurations that optionally improve the efficiency of hybrid vehicles are discussed herein.