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by Tim Beissmann

Audi will upgrade part of its vehicles’ electrical system from 12 to 48 volts, allowing it to integrate new technologies and increase the power and efficiency of its cars.

Audi recently showcased some of the 48-volt electrical system’s potential in its RS5 TDI and A6 TDI concepts. Both of those vehicles are fitted with an electrically powered compressor designed to act like a supercharger from just above zero rpm to counter turbo lag. The compressor operates independently of the engine load, markedly improving acceleration performance.

Audi says the 48-volt system is also ideal for dynamic chassis control systems.

The German car maker will unveil a variety of new applications for the technology in the near future.

audi-48-volt-system

In the current development version (above), a compact lithium-ion supplies 48 volts during the engine-off phases, and a DC/DC converter integrates the conventional 12-volt electrical system.

The lithium-ion battery works in collaboration with a new efficiency-optimised alternator to effectively operate as a mild-hybrid system.

Audi says the powerful alternator achieves an energy recovery output of 10kW – significantly more than current systems – and translates to a saving of 10 grams of CO2 per kilometre, which is equivalent to about 0.4 litres of fuel per 100km.

The car maker says the 48-volt system has become a necessity because current 12-volt electrical systems have reached their capacity and are no longer capable of meeting the demands of features such as high-performance compressors.

The technology is expected to reach production as early as 2015. Speaking with CarAdvice last month, Audi V6 TDI development manager Sven Beechle confirmed the RS5 TDI concept’s drivetrain was “basically [ready] for production”, and when pressed for dates, suggested “wait and see, next year is a nice year…”

Watch our video review of the Audi RS5 TDI concept car




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