The S-class is Mercedes-Benz's flagship sedan, the pinnacle of luxury. Since its 2007 model update, it has sported V-8 and V-12 engines. But upcoming European CO2 regulations caused Mercedes-Benz to explore a lower emission model, hence the S400 Hybrid.
The power plant, based on a 3.5-liter V-6 engine, uses a mild hybrid system comprised of a 20 horsepower motor and a lithium ion battery pack. The S400 Hybrid represents the first use of lithium ion battery chemistry in a major production hybrid vehicle.