Abstract: A geartrain for a powertrain system is disposed to transfer mechanical power between an internal combustion engine, an electric machine and a driveline. The geartrain includes a flywheel, a torque converter, an off-axis mechanical connection and a transmission gearbox. The off-axis mechanical connection includes a first element rotatably coupled to a second element. The flywheel is coupled to a crankshaft of the internal combustion engine. The torque converter includes a pump, a turbine and a pump hub, and the transmission gearbox includes an input member. The pump of the torque converter is coupled to the flywheel, and the pump hub is coupled to the first element of the off-axis mechanical connection. The second element of the off-axis mechanical connection is coupled to a rotor of the electric machine, and the turbine of the torque converter is coupled to the input member of the transmission gearbox.

Abstract: A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. A second electric machine is coupled to the engine to provide torque to start the engine from an inactive state. A high-voltage power source is configured to power both of the first electric machine and the second electric machine over a high-voltage bus. A propulsion controller is programmed to start the engine using cranking torque output from the second electric machine powered by the high-voltage power source. The controller is also programmed to operate both of the first electric machine and the combustion engine to propel the vehicle in response to an acceleration demand greater than a threshold. The controller is further programmed to decouple the engine and propel the vehicle using the first electric machine in response to vehicle speed less than a speed threshold.

Abstract: A vehicle propulsion system includes an engine and a first electric machine each configured to selectively provide torque to propel the vehicle. A second electric machine is coupled to the engine to provide torque to start the engine from an inactive state. A high-voltage power source is configured to power both of the first electric machine and the second electric machine over a high-voltage bus. A propulsion controller is programmed to start the engine using cranking torque output from the second electric machine powered by the high-voltage power source. The controller is also programmed to operate both of the first electric machine and the combustion engine to propel the vehicle in response to an acceleration demand greater than a threshold. The controller is further programmed to decouple the engine and propel the vehicle using the first electric machine in response to vehicle speed less than a speed threshold.

Abstract: A geartrain for a powertrain system is disposed to transfer mechanical power between an internal combustion engine, an electric machine and a driveline. The geartrain includes a flywheel, a torque converter, an off-axis mechanical connection and a transmission gearbox. The off-axis mechanical connection includes a first element rotatably coupled to a second element. The flywheel is coupled to a crankshaft of the internal combustion engine. The torque converter includes a pump, a turbine and a pump hub, and the transmission gearbox includes an input member. The pump of the torque converter is coupled to the flywheel, and the pump hub is coupled to the first element of the off-axis mechanical connection. The second element of the off-axis mechanical connection is coupled to a rotor of the electric machine, and the turbine of the torque converter is coupled to the input member of the transmission gearbox.