SYSTEM AND METHOD FOR OPERATING A HYBRID VEHICLE

A system and method of operating a hybrid vehicle having a hybrid powertrain including a motor-generator unit, a battery electrically connected to the motor-generator unit, an engine, and a transmission engageably connected to the engine and the motor-generator unit, the transmission having a plurality of gears. The hybrid vehicle also includes a controller for controlling the hybrid powertrain. The controller is configured to determine a gear for the hybrid vehicle based on a retarding capability of the hybrid powertrain and a grade or slope of a terrain. The retarding capability is based on a state of charge of the battery and at least one of a weight of the hybrid vehicle or a rolling resistance of the hybrid vehicle.