Hybrid Vehicles

Hybrid technology has many uses outside the realm of personal transportation. Perhaps one of the most effective examples of this is the GMability sponsored hybrid bus program, where GM's Allison Electric Drives System is being used to power more environment-friendly buses.

The hybrid system delivers up to 60 percent better fuel economy than the conventional diesel systems used in city buses. Buses equipped with the hybrid system produce much lower hydrocarbon and carbon monoxide emissions than normal diesel buses, lowering particulate emissions (tiny pieces of soot and dust) by 90 percent and nitrogen oxide (NOx) emissions by up to 50 percent. Buses equipped with the Allison hybrid system also deliver 50 percent better acceleration than a bus equipped with a normal diesel powertrain.

Here's how hybrid technology works: Hybrid systems use two sources of power to move a vehicle — the engine and the battery. In the parallel hybrid system, the diesel engine acts as a generator, producing the electrical power needed to keep the battery charged. The engine is attached to a drive unit that provides an infinitely variable power ratio to the wheels. This allows the engine in a hybrid system to run more efficiently, quietly and cleanly.

Other hybrid vehicle applications besides public transportation include use in commercial fleets, construction, and extended distance search and rescue.