Are all hybrids utilized for range extension?
No. Hybrid-electric vehicles can either be charge sustaining or non-charge sustaining; a product of the size generator and the operating demand of the service. A charge sustaining hybrid-electric bus will operate as long as fuel is available to operate the auxiliary power unit (APU). The generator is large enough to provide the necessary amount of electricity to propel the bus, regardless of its application. A charge non-sustaining hybrid utilizes a generator that may or may not maintain the batteries, depending on the application. Thus, if the bus runs out of the fuel necessary to operate the APU, and the batteries are depleted, the bus will not operate, even if more fuel for the APU is added.
