Patent ID: 7128677

Claim:
A powertrain for a hybrid electric vehicle having an engine, an electric generator and an electric motor acting as a pair of drive power sources for driving vehicle traction wheels, the powertrain comprising: gear elements drivably connecting the pair of power sources to the traction wheels through first and second geared power flow paths, at least one geared power flow path having at least two gear ratios; one of the pair of drive power sources being connected by the gear elements to the traction wheels through the first geared power flow path; the first geared power flow path comprising a first planetary gear unit, the first planetary gear unit having a sun gear connected to the generator, a carrier connected to the engine and a ring gear connected drivably to one gear element of a second planetary gear unit; the engine defining one power source on an engine axis and the motor defining in part another power source on a motor axis; and a friction element sub-assembly for the second planetary gear unit establishing selectively each of the gear ratios; the motor being connected drivably to the traction wheels through fixed ratio gear elements and a second gear element of the second planetary gear unit being connected drivably to the traction wheels to complement motor driving power.