The electrically variable transmission family of the present invention
provides low-content, low-cost electrically variable transmission
mechanisms including first, second and third differential gear sets, a
battery, two electric machines serving interchangeably as motors or
generators, and six selectable torque-transfer devices, which may include
a dog clutch. The selectable torque transfer devices are engaged singly
or combinations of two to yield an EVT with a continuously variable range
of speeds (including reverse) and up to four mechanically fixed forward
speed ratios. The torque transfer 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.