US Patent 7465251 Hybrid electric vehicle

A hybrid electric drive system for a motor vehicle includes a heat engine, a first motor, a second motor, and a planetary gear unit. The planetary gear unit includes at least a sun gear (an input element), a ring gear (an input element) and a pinion carrier (an output element). The engine is connected to and applies torque on one of the input elements. The first motor is connected to the engine shaft and is to start the engine while the vehicle is either moving or standing still, and to generate electrical power when the engine is running. The second motor is connected to and applies torque on the other input element The carrier of the planetary gear unit is connected a drive shaft to drive the wheels.