The electrically variable transmission family of the present invention
provides low-content, low-cost electrically variable transmission
mechanisms including three or four differential gear sets, a battery, two
electric machines serving interchangeably as motors or generators, seven
or eight selectable torque-transfer devices and possibly a dog clutch.
The selectable torque transmitting devices are engaged to yield an EVT
with a continuously variable range of speeds (including reverse) and up
to six mechanically fixed forward speed ratios. The torque transmitting
devices and the first and second motor/generators are operable to provide
five operating modes in the electrically variable transmission, including
battery reverse mode, EVT reverse mode, reverse and forward launch modes,
continuously variable transmission range mode, and fixed ratio mode.