My Mercedes Car: The New Mercedes-Benz SL: Chassis And Suspension

My Mercedes Car: The New Mercedes-Benz SL: Chassis And Suspension

Powerful when accelerating, effortlessly superior at every speed, zappy on winding stretches - the new SL is a shining example, displaying perfect manners on all the world鈥檚 roads and in all driving situations. What鈥檚 more, it also pampers all the senses with any amount of fun at the wheel. For these emotive experiences SL drivers can thank the potent engines - and above all the sporty, agile tuning of the suspension - which is nevertheless very comfortable, being offered in the form of two different systems for the SL. The SL features semi-active adjustable damping as standard. The optional active suspension system ABC (Active Body Control) is offered as an alternative. The spring struts which come as part of the standard equipment combine a steel spring with a continuously adjustable damper. Its damping properties can be varied via an electrically controlled valve. Continuous adjustment of the damping in accordance with the respective driving situation is taken care of fully automatically by control electronics which record the driving condition in question via sensors. The control unit uses the sensor data to determine the necessary damping forces for optimum comfort and handling.

On this basis it steplessly regulates the damping valves at every wheel within a broad damping characteristic so that sprung mass vibrations such as lifting, rolling and pitching are minimised on uneven roads. As a result, the new SL gives its occupants a smooth ride even on poor roads, without relinquishing any driving dynamics. The semi-active adjustable damping also rapidly counteracts sprung mass vibrations caused by the driver, by adjusting the damping characteristics. Setting the basic characteristics of the suspension is still left to the driver, however, using a switch that enables them to choose from a broad spectrum ranging from comfortable to sporty damping characteristics. A variant of this suspension is offered in the AMG Sports package. As an option the new SL is available with the unique active suspension system ABC (Active Body Control) as an alternative. It has been further improved for the new SL by the Mercedes-Benz chassis and suspension specialists. This system鈥檚 highly effective control elements are spring struts with a hydraulic steel cylinder arranged in line with the steel spring.

When this cylinder retracts and extends, it actively adjusts the length of the spring and therefore the spring force in the spring strut. This eliminates the need for torsion bars at the front and rear axle. With this technology an automatically controlled electronic system permanently adjusts the suspension to suit the driving situation and the road condition without any perceptible delay. This means that the active suspension system ABC can raise comfort to a high level, whilst simultaneously improving the roadster鈥檚 driving dynamics. This is possible as it almost completely compensates the vehicle body鈥檚 rolling and pitching movements when accelerating, braking and cornering. In addition to this, at the touch of a button it offers a unique, further increased spread of suspension settings between sports and comfort. As the vibrations initiated by irregularities in the road surface are greatly reduced, the occupants in the SL experience a vehicle with perfect absorption capacity on poor roads. Above all it is alternating sprung mass vibrations (鈥渃ross-pitching鈥? which are extremely minimal.

Sprung mass vibrations which arise through the driver鈥檚 influence are also almost entirely ironed out - this is the case, for instance, when the body rolls during steering or when there is pitching during braking and accelerating. The occupants experience a vehicle which drives 鈥渁s if on rails鈥? but without having to pay for this with the usual reduction in ride comfort which is typical of sports suspensions. As the ABC system modifies the roll torque distribution depending on the driving speed, the driver experiences handling which changes with the driving speed. It varies from motoring pleasure where one can afford it in driving dynamics terms to directional stability where it is most needed. In other words, on winding rural roads the roadster moves with nimble agility, and on motorway stretches it stays safely on track and does not worry the driver with any nervous reactions. The ABC system is also fitted with a hydraulic all-round level control system, thus ensuring a constant vehicle level irrespective of the load.

When the engine is running, the driver can raise the level of the vehicle at the touch of a button, both when the vehicle is at a standstill and during the journey. Thanks to a new feature in the SL, if the level is raised by 50 millimetres in this way, the ground clearance for rough roads or ramps is increased. In addition, the SL fitted with ABC is automatically lowered by up to 13 millimetres at high speeds, thus lowering the centre of gravity and wind resistance - and therefore also the fuel consumption. The track and wheel suspension are the same in the case of both suspension variants. In favour of sporty, agile and handling which can be safely kept under control, the new SL has a considerably wider track than the predecessor (front axle plus 38 mm, rear axle plus 63 mm). At the front axle, the tried-and-trusted principle of the 4-link front suspension has been adopted from the previous model series. It achieved superb results where comfort, dynamism, agility plus active and passive safety are concerned.