Variable ratio power-split hybrid transmission

A transmission comprising:

• an input member;
• an output member;
• a stationary member;
• a first planetary gear set and a second planetary gear set, each planetary gear set having a first member, a second member, and a third member;
• a first electric motor/generator having a first rotor connected for rotation with the first member of the first planetary gear set and a first stator grounded to the stationary member;
• a second electric motor/generator having a second rotor connected for rotation with the second member of the first planetary gear set and a second stator grounded to the stationary member;
• wherein the second member of the first planetary gear set is connected for common rotation with the output member;
• wherein the first member of the second planetary gear set is connected for common rotation with the input member;
• wherein the third member of the second planetary gear set is grounded to the stationary member;
• a first torque-transmitting mechanism selectively engageable to establish torque flow between the first member of the second planetary gear set and the third member of the first planetary gear set;
• a second torque-transmitting mechanism selectively engageable to establish torque flow between the second member of the second planetary gear set and the third member of the first planetary gear set;
• the first and second torque-transmitting mechanisms thereby providing two different speed ratios between the input member and the third member of the first planetary gear set;
• and
• at least one controller operable to control engagement of the torque-transmitting mechanisms and the motor/generators so that the transmission thereby establishes a first input-split electrically-variable operating mode when the first torque-transmitting mechanism is engaged, the engine is on, and the motor/generators function as motors or generators, and a second input-split electrically-variable operating mode when the second torque-transmitting mechanism is engaged, the engine is on, and the motor/generators function as motors or generators, the first and second input-split electrically-variable operating modes having different gear ratios between the input member and the first planetary gear set.

A transmission comprising:

• an input member;
• an output member;
• a stationary member;
• a first and a second planetary gear set each having a first member, a second member and a third member;
• a power-split unit including the first planetary gear set and having:
• a first electric motor/generator having a first rotor connected for rotation with the first member of the first planetary gear set and a first stator grounded to the stationary member;
• a second electric motor/generator having a second rotor connected for rotation with the second member of the first planetary gear set and a second stator grounded to the stationary member;
• wherein the second member of the first planetary gear set is connected for common rotation with the output member;
• a ratio-changing unit including the second planetary gear set and having:
• a first torque-transmitting mechanism selectively engageable to establish torque flow between the first member of the second planetary gear set and the third member of the first planetary gear set;
• a second torque-transmitting mechanism selectively engageable to establish torque flow between the second member of the second planetary gear set and the third member of the first planetary gear set;
• the first and second torque-transmitting mechanisms thereby providing two different speed ratios between the input member and the third member of the first planetary gear set;
• wherein the first member of the second planetary gear set is connected for common rotation with the input member;
• wherein the third member of the second planetary gear set is grounded to the stationary member;
• wherein the first member of the first planetary gear set is a sun gear member, the second member of the first planetary gear set is a ring gear member, and the third member of the first planetary gear set is a carrier member that supports pinion gears that mesh with the sun gear member and the ring gear member;
• wherein the first member of the second planetary gear set is a carrier member, the second member of the second planetary gear set is a sun gear member, and the third member of the second planetary gear set is a ring gear member;
• wherein the carrier member supports pinion gears that mesh with the sun gear member and the ring gear member;
• and
• wherein each of the torque-transmitting mechanisms is engaged at respective different predetermined operating conditions selected so that speeds of the first and second rotors remain within a predetermined range of speeds.