DETROIT—The old-fashioned fan belt is losing its grip.
The familiar toothed rubber belt, a staple of car engines for nearly a century, is driving fewer mechanical components as electricity takes over more functions under the hood.
The belt, originally dubbed the fan belt because it connected the crankshaft to the engine's cooling fan, now typically is called the accessory drive belt.
Not only has the number of accessory drive belts decreased from as many as four on some 1970s and "80s engines to just one today, but so has the length.
The Chevrolet Volt is down to one small belt that drives only the water pump.
Engineers have been replacing belt-driven accessories, such as the power steering and water pumps, with more energy efficient, electrically driven components.
Belt-driven systems typically draw power constantly. Electric systems use energy only when needed.
Other parts that are candidates for removal from accessory belts are the air conditioner and alternator, and in diesel engines a vacuum pump.