US Patent 10005351 Hybrid powertrain for vehicle

A hybrid powertrain for a vehicle includes: a planetary gear system including coaxial double pinions each having a first pinion and a second pinion that have different diameters and are provided to rotate coaxially; a carrier carrying the coaxial double pinions; and four rotation elements through which power is input and output. The hybrid powertrain further includes an engine, a first motor generator, a second motor generator, and an output shaft that are respectively connected to the four rotation elements of the planetary gear system.