SLS AMG E-CELL: the high-voltage gullwing
06/21/2010
Mercedes-Benz
Mercedes-AMG is rising to the challenges of the automotive future: the SLS AMG E-CELL showcases state-of-the-art development of an exciting super sports car with a zero-emission high-tech drivetrain. Boasting a power output of 526 hp and 649 lb-ft of torque, this prototype vehicle from AMG offers exceptional performance. The gullwing with electric drive is part of the company strategy entitled "AMG Performance 2015" which aims to continually reduce fuel consumption and emissions.
With the SLS AMG E-CELL, Mercedes-AMG is providing a glimpse of its latest
development project - a powerful and locally emission-free super sports car.
Finished in fluorescent "AMG lumilectric magno" paint, the gullwing offers a glimpse at a possible small series production vehicle and at the same time reflects the innovative strength and development expertise of the AMG per-formance brand.
"We take social responsibility very seriously and with the SLS AMG E-CELL we are demonstrating a further milestone in our "AMG Performance 2015" strategy. It is our goal to continually reduce the fuel consumption and emis-sions of new models in the coming years, while at the same time enhancing the core brand value of performance", explains Ola Källenius, chairman of the board (from 1 July 2010) of Mercedes-AMG GmbH. With the SLS AMG E-CELL, the performance brand of Mercedes-Benz is launching a totally in-novative drivetrain for super sports cars, reaching new territory in this mar-ket segment.
The ground-breaking drive system boasts some impressive highlights: pow-erful traction is provided by four synchronous electric motors with a com-bined peak output of 526 hp and a maximum torque of 649 lb-ft. The four compact electric motors each achieve a maximum rpm of 12,000 rpm and are positioned near the wheels. As a result, compared with wheel-hub mo-tors the unsprung masses are substantially reduced. One transmission per axle transmits the power.
Acceleration from zero to 60 mph in 4 seconds
When it comes to dynamics, the electrically-powered SLS AMG makes a statement: the gull-wing model accelerates from zero to 60 mph in 4 sec-onds - which almost puts it on the same high level as the SLS AMG with 6.3-liter V8
engine developing 563 hp (0-60 mph in 3.7 seconds).
Further driving excitement is provided by the agile accelerator response and straight-line performance: unlike the combustion engine, torque build-up with an electric motor is instantaneous - maximum torque is available virtu-ally from a standstill. The spontaneous torque build-up and effortless power delivery - which does not diminish by any interruption of tractive power - are combined with engine running characteristics which are totally free of vibra-tion. Four motors, four wheels: the intelligent and permanent all-wheel drive of the electric SLS guarantees driving dynamics at the highest level, while at the same time providing the best possible active safety. All four driven wheels achieve optimal traction, independent of weather conditions.
This very special gullwing is therefore able to "electrify" the driver with a completely unique, effortlessly superior and emotional super sports car driv-ing experience, even at this early, prototype stage of development. In brief: the SLS AMG E-CELL is true to the AMG brand.
High-voltage lithium-ion battery provides 400 v and 40 Ah
The SLS AMG E-CELL drive incorporates a liquid-cooled high-voltage lith-ium-ion battery featuring a modular design with an energy content of 48 kWh and a capacity of 40 Ah. The maximum electric load potential of the battery, which consists of 324 lithium-ion polymer cells, is 480 kW, which is an absolute best figure in the automotive sector. Another technical feature of this considerable performance is the intelligent parallel circuit of the individ-ual battery modules - this also helps to maximize the safety, reliability and service life of the battery. The 400-volt battery is charged by means of tar-geted recuperation during braking while the car is being driven.
Key data at a glance:
SLS AMG E-CELL
Max. output 526 hp
Torque 649 lb-ft
0 - 60 mph 4.0 s
Rated capacity 40 Ah (at 400 V)
Energy content 3 x 16 kWh = 48 kWh
High-performance electronic control as well as effective cooling of all
components
A high-performance electronic control system converts the direct current from the high-voltage battery into three-phase alternating current which is required for the synchronous motors and regulates the energy flow for all operating conditions. Two low-temperature cooling circuits ensure that the four electric motors and the power electronics are maintained at an even operating temperature. A separate low-temperature circuit is responsible for cooling the high-voltage lithium-ion battery. In low external temperatures, the battery is quickly brought up to operating temperature with the aid of an electric heating element. This helps to preserve the overall service life of the battery. In extremely high external temperatures, the cooling circuit for the battery can be additionally boosted with the aid of the air conditioning sys-tem.
Optimum weight distribution and low center of gravity
The purely electric drive system was taken into consideration early in the development of the SLS AMG. Thus, the SLS easily integrates the high-performance, zero-emission technology into its structure: for example, the four electric motors and the two transmissions can be positioned as close to the four wheels as possible and very low down in the vehicle. The same ap-plies to the modular high-current battery, whose modules are located in front of the firewall, in the center tunnel and behind the seats. Advantages of this solution include the vehicle's low center of gravity and balanced weight dis-tribution - ideal conditions for optimum handling, which the electrically-powered SLS AMG shares with its gasoline-powered sister model.
The installation of the drive components required no changes whatsoever to the car's weight-optimized aluminum spaceframe, and there were just as few constraints when it came to maintaining the excellent level of passive safety and high degree of long-distance comfort that are hallmarks of Mer-cedes-Benz cars.
New front axle design with pushrod damper struts
The additional front-wheel drive called for a newly designed front axle: unli-ke the series production vehicle with AMG V8 engine, which has a double wishbone axle, the SLS AMG E-CELL features an independent multilink suspension with pushrod damper struts. This is because the vertically-arranged damper struts in the series SLS had to make way for the additional drive shafts. As is usual in a wide variety of racing vehicles, horizontal damper struts are now used, which are operated via separate push rods and transfer levers.
Thanks to this sophisticated front-axle design, which has already been tried and tested in the racing world, the agility and driving dynamics of the electri-cally-powered SLS AMG attain the same high levels as the V8 variant. An-other distinguishing feature is the speed-sensitive power steering with rack-and-pinion steering gear: the power assistance is implemented electrohy-draulically rather than just hydraulically.
AMG ceramic composite brakes for perfect deceleration
The prototype vehicle is slowed with the aid of AMG ceramic composite brakes, available as an optional extra for the series production model, which boast extremely short stopping distances, a precise actuation point and out-standing fade resistance, even in extreme operating conditions. The over-sized discs - measuring 15.8 x 1.5 in. at the front and 14.2 x 1.3 in. at the rear - are made of carbon fiber-strengthened ceramic, feature an integral de-sign all around and are connected to an aluminum bowl in a radially floating arrangement.
The ceramic brake discs are 40 percent lighter in weight than the conven-tional, grey cast iron brake discs. The reduction in unsprung masses not only improves handling dynamics and agility, but also ride comfort and tire grip. The lower rotating masses at the front axle also ensure a more direct steering response - which is particularly noticeable when taking highway bends at high speed. The ABS and ESP(R) systems have been adapted to match the special handling of the permanent all-wheel drive.
Full-LED headlamps and automatically extending front splitter
The clean, exciting design of the prototype vehicle boasts a number of mi-nor yet extremely effective modifications. At the front, the dynamically shaped full-LED headlamps with integrated daytime driving lights immedi-ately catch the eye: they help to optimize the vehicle's energy efficiency, since they require less power compared with regular bi-xenon headlights. The wider radiator grille also has a new look, and now comes with trans-verse slats instead of a diamond-pattern. The air outlet openings on the hood and the vehicle sides have also been modified for enhanced aerody-namics. All trim and detachable parts, which are finished in chrome or silver shadow on the standard SLS AMG, are now finished in matte black.
The front apron has not only been brought further forward, but also helps optimize airflow to the underbody. This improves wind resistance while re-ducing downforce. An extendable front splitter enhances this effect: in paral-lel with the automatic rear spoiler, it extends downwards by three inches at speeds above 75 mph and helps to further accelerate the air which travels beneath the car. When it reaches the area of the rear axle, the air enters the rear diffuser which, due to the lack of an exhaust system, features a steeper angle, thus increasing downforce at the rear axle and in turn further enhanc-ing the aerodynamic balance. The vehicle's AMG 10-spoke light-alloy wheels feature a new, smooth-surfaced design and are fitted with 265/35 R 19 (front) and 295/30 R 20 (rear) tires.
Interior with new display instruments for electric drive
The transformation from gasoline to electric super sports car also called for some specific changes to the interior. As a result, the AMG instrument clus-ter and center console in particular both feature a new design. The new AMG instrument cluster provides information on speed, charge status of the battery and the estimated range. The newly designed center console now houses a 10-inch touchscreen, which driver and passenger can use to con-veniently operate all of the audio, climate and navigation functions, and also obtain information on the flow of power from the four electric motors.
The AMG Drive Unit, which is angled towards the driver, houses buttons for starting the motor, and the ESP(R) functions, the AMG memory function and the extendable front splitter and rear spoiler. Using three new buttons, the driver can switch simply between P, R and D. The park setting is also enabled auto-matically by switching the electric motors off.
The interior appointments are dominated by high-quality premium leather in a black/white color combination - it has been used not only on the sports seats, the performance leather/alcantara steering wheel and the door lin-ings, but also on the broad center console which runs towards the back of the vehicle between the seats.