Abstract: A powertrain includes a countershaft, a gearset including a sun gear, a carrier connected to an engine, a ring gear releasably held against rotation and connectable to the countershaft, and pinions supported on the carrier and meshing with the sun gear and ring gear, an electric machine connected to the sun gear and connectable to the countershaft, and a second electric machine driveably connected to the countershaft.

Abstract: A powertrain includes a gearset including a sun gear, a carrier, a ring gear connected to a countershaft, pinions supported on the carrier and meshing with the sun gear and ring gear; a second gearset connectable to an engine, for overdriving a generator; a clutch for releasably connecting the engine and carrier; a second clutch for releasably connecting the sun gear and the generator; and a motor connected to a countershaft. Operation of the powertrain can be readily switched between powersplit mode and series mode.

Abstract: Systems and methods provide voltage stability for a low voltage bus coupling a DC/DC converter with a low voltage load comprising one or more vehicle accessories. The DC/DC converter can be coupled to a high voltage battery, the low voltage load, and a starter circuit configured for starting an engine. Prior to engaging a starter motor to start the engine, the DC/DC converter can be isolated from the starter circuit so as to be shielded from any large current demand during an engine start event. While starting the engine, the starter motor can draw current from a secondary battery, while the DC/DC converter provides a sufficient and stable voltage to the vehicle low voltage accessories. After completion of the engine start event, the DC/DC converter can be recoupled to the starter circuit, allowing the high voltage battery to charge the secondary battery.

Abstract: A powertrain includes a gearset including a sun gear, a carrier, a ring gear connected to a countershaft, pinions supported on the carrier and meshing with the sun gear and ring gear; a second gearset connectable to an engine, for overdriving a generator; a clutch for releasably connecting the engine and carrier; a second clutch for releasably connecting the sun gear and the generator; and a motor connected to a countershaft. Operation of the powertrain can be readily switched between powersplit mode and series mode.

Abstract: A powertrain includes a countershaft, a gearset including a sun gear, a carrier connected to an engine, a ring gear releaseably held against rotation and connectable to the countershaft, and pinions supported on the carrier and meshing with the sun gear and ring gear, an electric machine connected to the sun gear and connectable to the countershaft, and a second electric machine driveably connected to the countershaft.

Abstract: A method for controlling a power-off shift from a current gear to a target gear in a hybrid electric powertrain including an engine, electric motor and automatic transmission includes the steps of determining an initial target speed for the current gear, operating the motor at the initial target speed, repetitively determining a current gear ratio, a output shaft speed during the gear ratio change, a time rate of change of output shaft speed, using the current gear ratio, the current speed of the output shaft and the time rate of change of output shaft speed repetitively to determine a current target speed, and operating the motor at the current target speed until a gear change to the next gear is completed.

Abstract: A method for controlling a power-off shift from a current gear to a target gear in a hybrid electric powertrain including an engine, electric motor and automatic transmission includes the steps of determining an initial target speed for the current gear, operating the motor at the initial target speed, repetitively determining a current gear ratio, a output shaft speed during the gear ratio change, a time rate of change of output shaft speed, using the current gear ratio, the current speed of the output shaft and the time rate of change of output shaft speed repetitively to determine a current target speed, and operating the motor at the current target speed until a gear change to the next gear is completed.