Patent ID: 7256510

Claim:
An electro-mechanical transmission comprising: an input member to receive power from an engine; an output member for delivering power from the transmission; a single motor/generator, wherein the transmission is characterized by an absence of another motor/generator affecting power flow between the input member and the output member; at least one differential gear set having a plurality of members including at least a first member, a second member and a third member; wherein said input member, said output member and said motor/generator are each operatively connectable with different ones of said members of said at least one differential gear set; a first torque-transmitting mechanism selectively engageable to establish a first continuously variable operating mode characterized by a first range of speed ratios; and a second torque-transmitting mechanism selectively engageable to establish a second continuously variable operating mode characterized by a second range of speed ratios; wherein engagement of one of said first and second torque-transmitting mechanisms and disengagement of the other of said first and second torque-transmitting mechanisms to shift between said respective continuously variable operating modes can be accomplished with essentially zero relative speed across both of said torque-transmitting mechanisms while both of said input member and output member are rotating.