Audi to Debut Electric Turbocharging in 2016

Audi AG tells Autocar it will introduce an electric turbocharger in 2016 in a sporty "S" version of its next-generation Q7 crossover vehicle. The company said earlier the technology would debut in a diesel engine.

The electric turbo will work in tandem with a conventional turbocharger, providing low-end boost until the main unit can spool up and take over.

Audi says its 7-kW system can create full boost in 250 milliseconds, thus eliminating virtually all turbo lag. The company has been testing the technology in two diesel prototypes. In an A6 large sedan, the system shortens the time it takes the car to accelerate from 37 mph to 75 mph to 8.3 seconds from 13.7 seconds. In a V-6 bi-turbo RS 5 sports car, the electric turbo delivers 553 lb-ft of torque at 1,250 rpm, enabling the car to zip from zero to 62 mph in about 4 seconds.

Both prototypes use a separate 48-volt electrical system and their own lithium-ion battery. Regenerative braking produces most of the power needed to operate the turbo unit. A DC/DC converter links the 48-volt system to the car's standard 12-volt electrical system. Audi has revealed no details about the production version of the system.

Audi considers electric turbocharging more useful in diesels, although the company has said it is considering a similar system for gasoline engines.