Mercedes’ S550 plug-in hybrid returns 84 mpg, hits 60 mph in 5.2 seconds

Mercedes-Benz has revealed a plug-in hybrid version of its S-Class flagship, and the German automaker says it’s one of a kind.

“The S550 plug-in hybrid is the first luxury sedan with the performance of a V8 and the fuel consumption of a compact model,” said Prof. Dr. Thomas Webber, Daimler Board of Management member and prefix enthusiast.

The Tesla Model S may take issue with some of those claims, but Merc’s latest hybrid is still at the forefront of a relatively new market.

A 3.0-liter, twin-turbocharged V6 provides the S550’s primary thrust with 329 horsepower and 354 pound-feet of torque. The hybrid’s electric counterpart bumps total output to 436 hp and 479 lb-ft.

Mercedes has never been particularly conservative with power in its upper ranges, though, so the S550’s 0 to 60 mph time of 5.2 seconds is no big surprise. What the engineers really focused on this time, however, is efficiency.

Related: 2014 Mercedes-Benz S-Class: Latest photos and new fully-heated details

The S550 returns an impressive 84-combined mpg on the New European Driving Cycle. The efficient turbochargers and electric motor certainly get major credit for this, but Mercedes’ new parallel hybrid modular system deserves commendation as well. Based on the brand’s 7-speed auto, the hybrid transmission employs an additional clutch between the gas engine and electric motor.

This grants the driver the ability to quickly and completely isolate the combustion engine from the electric motor during EV mode, and it also removes the need for a torque converter. This allows for quicker shifts, less rotational inertia, and less parasitic loss.

In addition, the car’s onboard computer continuously monitors battery life and upcoming traffic conditions, adjusting power output and gas/electric ratio accordingly. If you run low on juice, however, the car has you covered with a braking system that returns kinetic energy to the batteries. Completely run dry and the S550 can recharge in just 2 hours via the plug-in port on the rear bumper.

It’s worth noting that on electric power alone, the S550 can reach 87 mph and travel up to 20 miles emissions free.

Mercedes hasn’t released pricing for the hybrid luxury sedan yet, but expect it to fall somewhere near the $100,000 mark. This eclipses the $92,900 base price of the standard S550, but stays competitive with the $93,400 Tesla Model S Performance Sedan.

The S550 hybrid goes on sale spring 2015.