Mercedes-Benz Pioneers Fully Active Suspension

S-Class, CL Coupes and SL Roadsters Offer Active Body Control (ABC)

TORONTO, ON – Mercedes-Benz – the company that pioneered ABS anti-lock brakes, traction control and Electronic Stability Program (ESP) – offers the world's first production fully active suspension system.  For 2006, Mercedes-Benz offers the critically acclaimed ABC (Active Body Control) active suspension as standard equipment on all CL coupes and SL roadsters as well as the S55 AMG, S65 AMG and S600 sedans, while the system is optional on the S430 4MATIC™ all-wheel-drive and S500 sedans.

Active Body Control (ABC) virtually eliminates body pitch and roll during cornering, accelerating and braking.  While active suspension is capable of even leaning a car into every turn (like a motorcycle or airplane), Mercedes-Benz engineers use its interplay of hydraulic, electronic and mechanical parts to significantly reduce body roll.  An ABC Sport switch on the dash (the SL switch is on the lower centre console) can virtually eliminate roll if the driver prefers even sportier, flatter cornering. 

The Best of Both Worlds – Handling and Comfort

Active Body Control (ABC) helps to solve the old tradeoff between ride comfort and handling precision.  S-Class sedans and CL-Class coupes with ABC provide the same sumptuous ride comfort as with Airmatic air suspension, while simultaneously exhibiting crisper handling that surpasses many high-performance sports cars.

Four Lightning-Quick Hydraulic Pistons Are the Key

Mercedes-Benz' Active Body Control (ABC) uses four hydraulic pistons, one on top of each steel coil spring, as part of an integrated strut assembly.  Located between the body and the springs, these pistons apply additional forces in response to split-second signals from the ABC computer.  As a result, the pistons actually regulate the action of the springs in relation to incipient body movement, absorbing body vibrations with a frequency of up to five hertz.

One Computer, Four Control Valves, and 13 Sensors

A total of 13 sensors monitor body movement and vehicle level so that the ABC computer is supplied with new data every 10 milliseconds.  This sophisticated system senses body movement just as it begins, and makes adjustments accordingly.  Two sensors at each end of the car (one on each wheel) measure vehicle level, while nine sensors – mounted strategically on the vehicle body – detect vertical and transverse body movement.  Data from these sensors is processed every 120 milliseconds by the microprocessor to compute signals for operating hydraulic valves that control each of the four hydraulic pistons atop the springs.

High Hydraulic Pressure Gives Fast Response

A special engine-driven hydraulic pump generates 200 kgs per square centimeter (2,840 pounds per square inch) of oil pressure, which helps ensure that the four servos operate within a few milliseconds.  The system checks and re-checks itself every 10 milliseconds.  An accumulator, or pressure reservoir, at each end of the car keeps pressurized oil ready, so that the energy for split-second damping and springing is always available, and an oil cooler maintains the right operating temperature in the system.

Stabilizer Bars Not Needed

The Active Body Control (ABC) handles relatively low frequency body movements of five Hertz or lower, which means that stabilizer bars are no longer necessary.  However, higher frequencies are absorbed by conventional gas-pressurized shock absorbers and steel coil springs.  Although Mercedes engineers tested versions with different frequency ranges, its energy requirements, performance and fuel economy were best balanced by the chosen frequency range.

Twenty Years of Hard Work Pays off

Mercedes engineers built and tested the first active suspension early in 1978, but the digital control technology they needed did not yet exist.  They tested the first research vehicle with active suspension in 1987, and two years later, another version was developed for the Mercedes Group C racecar.  Although this low-frequency system made its debut in the 1991 C11 race car, its use was blocked by new Group C regulations.  That same year, this active suspension system appeared on the V12-powered C112 concept car.  An early version of Active Body Control (ABC) made its debut in 1996 at the Hanover Show on a special prototype for the Mercedes-Benz 0404 high-deck bus.

About Mercedes-Benz Canada

Mercedes-Benz Canada is responsible for the sales, marketing and service of the three brands within the Mercedes Car Group in Canada; Mercedes-Benz, smart, and Maybach.  Headquartered in Toronto, Ontario, Mercedes-Benz Canada employs approximately 900 people in 22 locations across Canada.  Through a nationwide network of 18 Mercedes-Benz owned retail operations and 35 authorized dealerships, Mercedes-Benz Canada sold 15,790 vehicles in 2005, the best year ever reported for Mercedes-Benz Canada Inc.

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