Electrically variable transmission having three planetary gear sets, two fixed constraints and a stationary member

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 a member of said first gear set with a stationary member;
• said first motor/generator being continuously connected with a member of said first or second gear set, or selectively connectable with a member of said first or third gear set;
• said second motor/generator being continuously connected with a member of said third gear set;
• and
• first, second and third torque transfer devices for selectively connecting said members of said first, second or third gear sets with a stationary member or with other members of said gear sets, said first, second and third torque transfer devices being engagable to provide an electrically variable transmission with a continuously variable range of speed ratios and at least one fixed forward speed ratio between said input member and said output member.

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 a member of said first gear set with a stationary member;
• said first motor/generator being selectively connected with a member of said first or third gear set;
• said second motor/generator being connected with a member of said third gear set;
• a first torque transfer device selectively connecting a member of said first or second gear set with a member of said third gear set;
• a second torque transfer device selectively connecting a member of said first or second gear set with a member of said third gear set;
• a third torque transfer device connected in parallel with one of said motor/generators for selectively preventing rotation thereof;
• wherein said first, second and third torque transfer devices are engagable to provide an electrically variable transmission with a continuously variable range of speed ratios and at least two fixed forward speed ratios.