US Patent 8668035 Electric traction system and method

A power exchange unit (PXU) is coupled to an existing manual transmission of a vehicle via a PTO port. An electric motor generator coupled to the PXU. A battery is electrically coupled to the motor generator for supplying power to propel the vehicle. A control unit is coupled to the motor generator and the battery and configured to switch operation of the vehicle between first and second modes, wherein in the first mode an internal combustion engine of the vehicle propels the vehicle, and in the second mode the motor generator propels the vehicle in a motoring mode.