Belt-driven generator starter systems for hybrid vehicles

A belt-driven generator starter system (BAS system) for a hybrid vehicle may include a first pulley, a first belt, a motor generator unit (MGU), a second pulley, a second belt, and a first clutch. The first belt surrounds the first pulley and a crankshaft pulley of an internal combustion engine. The MGU includes the second pulley and functions as an electric motor when the engine is started and as a generator for charging a battery when the engine is running. The second belt surrounds the second pulley and at least one drive pulley of an accessory unit. The first clutch couples / decouples the crankshaft pulley to / from the second pulley in response to operation of the engine.