Audi Touts 48-Volt Electrical System

Audi AG says it is preparing to equip unspecified diesel-powered models with a 48-volt electrical system to complement the standard 12-volt architecture.

Audi has shown diesel-powered A6 and RS 5 prototypes fitted with the dual system. Both cars are equipped with electrically powered superchargers made possible by the more powerful 48-volt circuit. Since the electric blowers operate independent of engine speed, they provide instant boost and thus improved acceleration performance.

Audi notes that 48-volt technology also enables new options for dynamic chassis control.

The higher voltage allows smaller cable cross-sections, resulting in lighter wiring with lower power dissipation. The company says it will "shortly begin unveiling a variety of applications."

The Audi system incorporates a lithium-ion battery to supply 48 volts when the engine is off. It also uses a special 10-kW alternator that is more than three times as powerful as the unit in a typical 12-volt system. A DC/DC converter integrates the 12-volt portion of the architecture.

Audi says the combination qualifies the powertrain as a mild hybrid that reduces carbon dioxide emissions by as much as 10 grams per kilometer.