Patent ID: 7172525

Claim:
An electrically variable transmission comprising: an input member to receive power from an engine; an output member; first and second motor/generators; first and second differentially geared planetary gear sets each having first, second and third gear members; said input member not being continuously connected with any member of said planetary gear sets, and said output member being continuously connected to said first member of said second planetary gear set; said first and second motor/generators each being continuously connected to at least one member of said planetary gear sets; said first member of said first planetary gear set being continuously connected with said third member of said second planetary gear set; a first torque transfer device selectively grounding said second member of said second planetary gear set; a second torque transfer device selectively connecting said second member of said second planetary gear set to said second member of said first planetary gear set; a third torque transfer device selectively grounding said third member of said second planetary gear set; a fourth torque transfer device selectively connecting said first member of said first planetary gear set with said input shaft; a fifth torque transfer device selectively grounding said third member of said first planetary gear set; and a sixth torque transfer device selectively connecting said third member of said first planetary gear set with said input shaft; wherein said torque transfer devices enable a mechanical-only reverse mode of operation, in addition to a continuously variable range of speed ratios and fixed forward ratio modes of operation.