Audi A8 - Mild Hybrid Electric Vehicle (MHEV) components
The new mild-hybrid technology (MHEV = mild hybrid electric vehicle) is standard with all A8 engines. It reduces fuel consumption by up to 0.7 liters (0.2 gal) per 100 kilometers (62.1 mi) in actual driving. The MHEV technology from Audi is based on a newly developed 48 volt main vehicle electrical system. It comprises a compact lithium-ion battery with an electrical capacity of 10 Ah, located in the luggage compartment underneath the loading floor of the A8, as well as a belt alternator starter (BSG) connected to the crankshaft.
The effects are impressive: in the speed range of 55 to 160 km/h (34.2 - 99.4 mph) the new A8 can coast with the engine off, if the driver releases the accelerator. The vehicle can then travel with zero emissions for up to 40 seconds. As soon as the driver steps on the gas again, the BAS prompts a swift, very smooth restart. The new 48-volt system allows a high recuperation power of up to 12 kW plus start-stop operation from 22 km/h (13.7 mph).