Hybrid transmission with gear-based starter and method of starting

A hybrid transmission for use with a vehicle having an engine, the vehicle having an electric-only mode where the engine is off and a hybrid mode where the engine is on, the hybrid transmission comprising:

• an engine connection member configured for connection with the engine;
• a motor/generator unit configured to selectively operate as a motor;
• a transmission gearing arrangement;
• a transmission input member connected with the transmission gearing arrangement;
• a torque transfer device controllable to transfer torque from the motor to the transmission input member upstream in power flow from the transmission gearing arrangement;
• a starter gear set, including a planetary gear set, positioned in power flow between the engine connection member and the motor, the starter gear set being selectively engageable with the transmission input member and the engine connection member;
• and
• the starter gear set including a disconnect clutch that is selectively engageable with the planetary gear set to lock the engine connection member and transmission input member to rotate together when the engine is on when the vehicle is operating in the hybrid mode.

A method of starting an engine connected with a hybrid transmission operating in all-electric mode to transition to hybrid mode, the method comprising:

• powering the transmission through a transmission input member connected to a torque transfer device via a motor powered by a battery when the vehicle is operating in all-electric mode;
• engaging a brake with a planetary gear set operatively connected between an engine connection member and the transmission input member prior to starting the engine whereby the transmission input member transfers torque to the engine connection member and starts spinning the engine connection member prior to starting the engine;
• and
• starting the engine with fuel when the engine speed is at about 300 rpm or an engine speed that is sufficient to sustain combustion.