| dc.description.abstract | Most of the current electric vehicles use a single reduction gear set powertrain architecture as their transmission. This is largely due to the fact that the electric motors, unlike engines, produce very high torques at a wide range of lower rotational speeds. Although such architectures allow for smooth power transmissions, there is still potential for improvement in the motor operation efficiency. The proposed powertrain architecture derives its inspiration from the Electronic Continuously Variable Transmissions (E-CVTs) which employ Motor-Generator Units (MGUs) and Planetary Gear Trains (PGTs) to achieve a wide and a continuous range of gear ratios. The E-CVTs have been successful in increasing the fuel economy of hybrid vehicles and since range anxiety continues to be a prime hurdle in large scale adaptation of electric vehicles, the possibility of using this technology to achieve range extension in electric vehicles is explored.
In this project, a simulation-based approach is used to evaluate a novel E-CVT configuration. The proposed E-CVT has an input-split, output coupled power-path configuration. By modulating the power split ratio between the mechanical (i.e. PGTs) and electrical drivelines (i.e. MGUs), a continuous range of gear ratios that facilitate a higher efficiency motor transmission is obtained. The operation zones for such ratios is subsequently determined through optimization of control strategy with the objective of obtaining a higher end-of-cycle SOC, subject to the vehicular constraints. The performance of the architecture is be bench-marked against both the federal highway and urban driving cycles. | en |
