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 four or five selectable torque - transfer devices . the selectable torque transfer devices are engaged singly or in combinations of two to yield an evt with a continuously variable range of speeds and 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 .