Among the veritable plethora of technologies encased within the new 4.7-L bi-turbo Mercedes-Benz S-Class Coupe (replacing the CL) at the 2014 Geneva Motor Show, one stood out as something very special. Called Active Curve Tilting Function (ACTF), it is arguably the automotive equivalent of a high-speed “kneedown” motorcyclist leaning a machine into a bend.
Its tilt action, orchestrated by the car’s Magic Body Control (MBC) system, was presaged in 2001 by Mercedes’ F400 Carving concept, then driven by this Automotive Engineering editor to experience wheels on the outside of a corner tilting steeply to enhance stability and reduce risk of skidding—a mind-focusing experience.
Prof. Dr. Thomas Weber, Daimler Board Member responsible for corporate research and Mercedes’ development, said of the system: “The S-Class Coupe leans into bends (between 30 km/h and 180 km/h) much like a motorcyclist. This reduces lateral acceleration acting on the occupants. It demonstrates the possibilities of Mercedes-Benz Intelligent Drive.”
The system uses the MBC’s ability to monitor the road 15 m (49 ft) ahead via a stereo camera (previously described by Automotive Engineering at http://articles.sae.org/12330/), but adds a transversal acceleration sensor and produces required lean via adjusting the pressure within hydraulic struts as part of the suspension system. The effect varies according to the radius of the curve and speed of the car, up to a maximum 2.5 degree. The Carving’s wheels tilted through 20 degree, but such an extreme was deemed unnecessary and unsuitable, not to mention very difficult to accommodate within the wheel arches of the S-Class Coupe—and alarming for other road users!
ACTF, claimed as a “world first” for series production cars, is switchable within three drive modes available via the car’s Active Body Control.
The new S-Class Coupe also incorporates technologies from its sedan sibling, with a headup display (HUD) providing speed, speed limit, navigation, and driving assistance messages—and a touch-pad for the driver.
As an option, Mercedes introduces what it calls “expressive headlamps,” each with 47 Swarovski crystals to provide a distinctive visual signature. They comprise 17 forming daytime running lights and 30 for the turn indicators. Full LED headlights are fitted. Part of each rear-light LED cluster is in the rear fender and trunk lid.
A panoramic roof has a surface area of 1.32 m² (14.2 ft²) with Magic Sky Control to switch transparency from light to dark.
With a more aggressive stance than many previous top-of-the-range Mercedes coupes and using concave and convex surfacing, the new S-Class is 5027 mm (197.9 in) long and 1411 mm (55.6 in) tall on a 2945-mm (115.9-in) wheelbase. 4Matic all-wheel drive is an option.
Interior details include airbag repositioning to a lower than normal level to facilitate a dashboard with a wrap-around top layer and a low “floating” section.
A touchpad is a distinctive part of the interior. Mercedes explains that, as on a smartphone, it allows all the head-unit functions to be operated using finger gestures. It also allows use of letters, numbers, and special characters to be entered in handwriting form in any of the head-unit’s languages. Controls for the multimedia system are positioned in a semi-circle around it.
The HUD incorporates a specular optics system and full color display module with 480 x 240 pixel resolution operating with high-power LEDs to project a virtual image—about 21 x 7 cm (8.3 x 2.8 in)—into the driver’s field of view. It is designed to appear to float some 2 m (6.6 ft) ahead and above the hood. Display brightness is adjusted automatically via a light sensor.
The new S-Class Coupe’s 328-kW (440-hp), 700-N·m (516-lb·ft) launch engine will be followed by further choices that are likely to include a V12.