Designed to quickly build up charge pressure, the system uses a conventional gas-driven turbocharger and an electrically-driven compressor.

Audi has announced they are testing an electric bi-turbo diesel engine.

Designed to quickly build up charge pressure, the system uses a conventional gas-driven turbocharger and an electrically-driven compressor which features a "small electric motor that can accelerate its turbine to very high speeds in an extremely short time." It promises to deliver "high levels of torque even at very low revs."

Detailed specifications haven't been announced, but Audi is testing the system on a modified 3.0-liter bi-turbo TDI. It normally develops 313 PS (230 kW / 309 hp) and 650 Nm (479 lb-ft) of torque, but Audi says the electric turbo gives the perception of a "distinct boost in performance."

Check out the press release for additional information

Audi electric bi-turbo engine revealed