Patent ID: 7347798

Claim:
An electrically variable transmission comprising: an input member to receive power from an engine; an output member; first and second motor/generators; first, second and third differential gear sets each having first, second and third members; said input member being continuously connected with at least one member of said gear sets, and said output member being continuously connected with another member of said gear sets; a first interconnecting member continuously connecting said first member of said first gear set with said first member of said second gear set; a second interconnecting member continuously connecting said second member of said first gear set with said second member of said second gear set; a third interconnecting member continuously connecting said third member of said second gear set with said first member of said third gear set; a fourth interconnecting member continuously connecting one of said members of the planetary gear sets with a stationary member or with a member of said third gear set; said first motor/generator being continuously connected with a member of said first, second, or third gear set; said second motor/generator being continuously connected with a member of said first, second or third gear set; a first torque transfer device selectively connecting a member of said first or second gear set with another member of the first, second, or third gear set; a second torque transfer device selectively connecting a member of said third gear set or the stationary member with another member of said first, second, or third gear set; a third torque transfer device connected in parallel with one of the first and second motor/generators for selectively preventing rotation of the motor/generator; and wherein said first, second, and third torque transfer devices are engageable to provide an electrically variable transmission with a continuously variable range of speed ratios and up to four fixed forward speed ratios.