Electrically variable transmision having three interconnected planetary gear sets

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 and with said second member of said third gear set;
• said first motor/generator being continuously connected with said first interconnecting member;
• said second motor/generator being continuously connected with a member of said second or third gear set;
• and
• first, second, third and fourth torque transfer devices for selectively interconnecting said members of said first, second or third gear sets with ground or with other members of said planetary gear sets, said first, second, third and fourth torque transfer devices being engageable alone or in pairs to provide an electrically variable transmission with a continuously variable range of speed ratios and four fixed forward speed ratios 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 and with said second member of said third gear set;
• said first motor/generator being continuously connected with said first interconnecting member;
• said second motor/generator being continuously connected with a member of said second or third gear set;
• and
• first, second, third, fourth, and fifth torque transfer devices for selectively interconnecting said members of said first, second or third gear sets with a stationary member or with other members of said planetary gear sets;
• wherein said first, second, third, fourth and fifth torque transfer devices are engageable singly or in combinations of two to provide an electrically variable transmission with a continuously variable range of speed ratios and four fixed forward speed ratios between said input member and said output member.