Single planetary, single motor/generator hybrid powertrain with three or more operating modes

A hybrid powertrain for a vehicle comprising:

• an engine;
• an input member, an output member, and a stationary member;
• a single planetary gear set having a ring gear member, a sun gear member and a carrier member;
• wherein the input member is connected for common rotation with the engine;
• wherein the output member is connected for common rotation with the carrier member;
• a single motor/generator continuously connected for common rotation with the sun gear member;
• without any other motor/generator operatively connected between the input member and the output member;
• a starter motor operatively connected to the engine for starting the engine;
• a first, a second, and a third torque-transmitting mechanism;
• wherein the first torque-transmitting mechanism is selectively engagable to connect the input member for rotation with the ring gear member;
• wherein the second torque- transmitting mechanism is selectively engagable to ground the ring gear member to the stationary member;
• and wherein the third torque-transmitting mechanism is selectively engagable to ground the sun gear member to the stationary member.

A hybrid powertrain for a vehicle comprising:

• an engine;
• an input member, an output member, and a stationary member;
• a single planetary gear set having a ring gear member, a sun gear member and a carrier member;
• wherein the input member is connected for common rotation with the engine;
• wherein the output member is connected for common rotation with the carrier member;
• a single motor/generator continuously connected for common rotation with the sun gear member;
• without any other motor/generator operatively connected between the input member and the output member;
• a starter motor operatively connected to the engine for starting the engine;
• a first, a second, and a third torque-transmitting mechanism;
• wherein the first torque-transmitting mechanism is selectively engagable to connect the input member for rotation with the ring gear member;
• wherein the second torque-transmitting mechanism is selectively engagable to ground the ring gear member to the stationary member;
• wherein the third torque-transmitting mechanism is selectively engagable to ground the sun gear member to the stationary member;
• a fourth torque-transmitting mechanism selectively engagable to connect the input member for common rotation with the sun gear member;
• at least one controller operable to monitor operating conditions of the motor/generator and operatively connected to the torque-transmitting mechanisms to engage the third torque-transmitting mechanism to brake the motor/generator and engage the first torque-transmitting mechanism, to thereby establish an engine-only operating mode in response to the monitored operating conditions indicative of motor failure so that no motor/generator is rotating during the engine-only operating mode.