A control process including the following steps is executed. The control process includes, at the time of switching from series-parallel mode to series mode, a step of reducing an engine torque, a step of releasing a clutch, a step of reducing a reaction torque of a first rotary electric machine and a step of increasing a torque of a second rotary electric machine, and, when synchronization is started and a step of increasing a positive torque of the first MG, a step of starting engagement of a clutch, and, when a rotation speed of the first rotary electric machine and a rotation speed of an engine are synchronous with each other, a step of engaging the clutch.

A control process including the following steps is executed. The control process includes, at the time of switching from series-parallel mode to series mode, a step of reducing an engine torque, a step of releasing a clutch, a step of reducing a reaction torque of a first rotary electric machine and a step of increasing a torque of a second rotary electric machine, and, when synchronization is started and a step of increasing a positive torque of the first MG, a step of starting engagement of a clutch, and, when a rotation speed of the first rotary electric machine and a rotation speed of an engine are synchronous with each other, a step of engaging the clutch.

Methods and systems are provided for improving torque control of a vehicle that includes simulated shifting of a step gear ratio transmission. In one example, a propulsive effort request is gradually incrementally increased or decreased to provide a smooth torque transition, thereby providing a smoother vehicle speed change and improve vehicle drivability.

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving a output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

A method of controlling a continuously variable electric drivetrain (CVED) including a high ratio traction drive transmission and at least one of a first motor-generator and a second motor-generator is disclosed. The method includes the steps of receiving a output speed, determining a kinematic output speed, and determining a slip state of the high ratio traction drive transmission based on a comparison of the output speed to the kinematic output speed.

An electromagnetic transmission assembly. The electromagnetic transmission assembly includes a stator having a central axis and a plurality of selectively-energized electromagnetic poles. A first rotor assembly is rotatably supported for rotation about the central axis. The first rotor assembly including a first rotor shaft and a castellated rotor including a plurality of radially arranged ferromagnetic pole portions disposed in a housing. A second rotor assembly is rotatably supported for rotation about the central axis. The second rotor assembly includes a second rotor shaft and a permanent-magnet rotor. The first rotor assembly is at least partially magnetically coupled to the second rotor assembly when the plurality of electromagnetic poles are energized.

An electromagnetic transmission assembly. The electromagnetic transmission assembly includes a stator having a central axis and a plurality of selectively-energized electromagnetic poles. A first rotor assembly is rotatably supported for rotation about the central axis. The first rotor assembly including a first rotor shaft and a castellated rotor including a plurality of radially arranged ferromagnetic pole portions disposed in a housing. A second rotor assembly is rotatably supported for rotation about the central axis. The second rotor assembly includes a second rotor shaft and a permanent-magnet rotor. The first rotor assembly is at least partially magnetically coupled to the second rotor assembly when the plurality of electromagnetic poles are energized.

On simultaneous shifts in which shift control of virtual gear positions overlaps shift control of mechanical gear positions, an electronic control unit is configured to delay output of a shift command on the virtual gear position such that shifts of the virtual gear position and the mechanical gear position are performed in synchronization. Therefore, the virtual gear position and the mechanical gear position are shifted in synchronization, irrespective of a difference between the shift response times, and the feeling of strangeness given to the driver due to shift shock, or the like, is suppressed.

A plurality of virtual gear positions are established by an electric continuously variable transmission, and the number of speeds of the virtual gear positions is equal to or larger than the number of speeds of mechanical gear positions of a mechanical stepwise variable transmission. One virtual gear position or two or more virtual gear positions is/are assigned to each mechanical gear position, and the mechanical gear position is shifted in the same timing as shift timing of the virtual gear position. The virtual gear positions assigned to each mechanical gear position when the mechanical gear position is upshifted are different from the virtual gear positions assigned to each mechanical gear position when the mechanical gear position is downshifted. Thus, the amount of heat generated in frictional engagement elements of the mechanical stepwise variable transmission is prevented from being increased.

A plurality of virtual gear positions are established by an electric continuously variable transmission, and the number of speeds of the virtual gear positions is equal to or larger than the number of speeds of mechanical gear positions of a mechanical stepwise variable transmission. One virtual gear position or two or more virtual gear positions is/are assigned to each mechanical gear position, and the mechanical gear position is shifted in the same timing as shift timing of the virtual gear position. The virtual gear positions assigned to each mechanical gear position when the mechanical gear position is upshifted are different from the virtual gear positions assigned to each mechanical gear position when the mechanical gear position is downshifted. Thus, the amount of heat generated in frictional engagement elements of the mechanical stepwise variable transmission is prevented from being increased.