Patent ID: 7169074

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 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; said first member of said second gear set being continuously connected with ground; said first motor/generator being continuously connected with a member of said first gear set; said second motor/generator being continuously connected with a member of said first or second gear set which is different from said member connected with said first motor/generator; a first torque transfer device selectively connecting a member of said first gear set with a member of said second gear set; a second torque transfer device selectively connecting a member of said first gear set with a member of said second gear set, the pair of members connected by said second torque transfer device being different from the pair of members connected by said first torque transfer device; a third torque transfer device selectively connecting a member of said first gear set with ground; and a fourth torque transfer device connected in parallel with said first or second motor/generator for braking rotation thereof; wherein said first, second, third and fourth torque transfer devices are engageable alone or in pairs to provide an electrically variable transmission with a continuously variable range of speed ratios and three fixed forward speed ratios.