R129 ADS

Features

Semi-supporting hydro-pneumatic suspension system

Reduced-support coil springs

Automatic speed-dependent lowering/raising of the vehicle level (adjustment range: -15/+30 mm)

Manual height adjustment (30 mm) from the normal position

Constant vehicle level, irrespective of the load

Fully automatic adaptive damping system (ADS)
- electronically controlled adaptation of the damping forces to the prevailing requirements of the wheel and body damping
- electronic control unit for the evaluation at sensor signals and the activation of the damping modules
- damping modules allow for 4 different damping stages at each wheel

Information and benefits

In the design of a car's suspension system, the contradictory aims of optimum comfort and maximum handling safety have to be optimized and optimally matched to all driving conditions. Conventional springing/damping systems are not up to these requirements, as they only have one setting for all the different parameter combinations of road condition, driving style and load. Yet they otter a satisfactory compromise between the different requirements — as our Mercedes-Benz cars prove every day

With the optionally available "level adjustment and control with automatic speed-dependent level adjustment and automatic damping system (ADS) at front and rear", however, we are offering for the first time a running gear system for the R129 which incorporates the very best in suspension technology that is currently possible.

This system is a combination of the "level adjustment and control at the front and rear axle" in the 190 E 2.516 (and 190 E 2,3-16). an automatic speed-dependent level adjustment and a fully automatic adaptive damping system (ADS).

This combination offers our customers the concentrated advantages of these excellently compatible suspension systems and gives active safety a new dimension.

Level adjustment and control at front and rear

This sub-system is in itself a combination of two systems:
- the semi-supporting hydro-pneumatic suspension system with level control and
- the level adjustment system at front and rear

Level adjustment at front and rear take place irrespective of the load and not only when the springs are compressed to a certain extent or as from a certain load, as is the case with a single level adjustment system, acting on the rear wheels only. This means that the vehicle level remains constant as long as the engine is running.

The suspension system consists of a hydro-pneumatic supporting part and semi-supporting coil springs. This is among other things the technical prerequisite for another advantage — the automatic speed-dependent level adjustment.

The level adjustment range amounts to a total of 45 mm and is divided into three settings:
— normal height
— lowered by 15 mm
— raised by 30 mm (if pre-selected manually)

The degree of level adjustment is automatically controlled as a function of speed.

By activating a speed switch in the speedometer the vehicle level is automatically adjusted to its lowest height when driving at higher speeds. In this case
— the car assumes a lower centre of gravity, the lift forces at the front axle are small = better roadholding and handling safety
— reduction of aerodynamic drag = lower fuel consumption

As a special precautionary measure when driving on poor road surfaces, the level of the car can be raised by 30 mm from its normal driving height by means of a rocker switch located in the instrument panel. Depending on the position of the rocker switch, the car level adjusts automatically and as a function of the driving speed as follows:
- Switch position: normal driving height The vehicle maintains this level (design level) when stationary and during driving
- If a speed of 122 km/h is exceeded, the vehicle is automatically lowered by 15 mm, If the Speed subsequently falls below 118 km/h, the system adjusts to normal driving height.

Switch position: raised level (+30 mm) The vehicle is raised by 30 mm and maintains this level when stationary and when cruising. When driving at speeds higher than 52 km/h, the level is lowered by 30 mm to its normal driving height; if the speed exceeds 122 km/h, the level is lowered another 15 mm. If the speed then drops below 118km/h, the normal level is adopted; at speeds below 48 km/h the higher level is selected again.

Adaptive damping system (ADS)

In addition to the automatic speed-dependent level adjustment, the adaptive damping system is another important new feature in the entire optionał system.

Since for safety reasons, a fixed damper setting has to cater for unfavourable yet tare operating conditions such as high payload, agressive driving style and bad roads rathet than favourable ones, the automobile manufacturers generally choose a taut damping system.

This is why driving on a good road might nevertheless feel somewhat uncomfortable. Adaptive shock absorbers make for better adjustment to the most varying road conditions and driving styles. The objectives of ADS are the following:
- quick adjustment of the dampers to the prevailing driving conditions.
- softer damping and reduced road roar and tyre vibration for a moderate driving style and smooth road surfaces
- tauter damping with improved vibration behaviour with high payloads, when changing lane, with a dynamic driving style on roads with many bends and on poor road surfaces.

The fully automatic and electronically controlled adaptive damping system (ADS) solves this problem with unexpected precision. It instantly adapts the damping forces to the requirements of the wheel and body at any given moment and is hence considerably more effective than any other manual or party automatic system on offer.
Together with the control unit, the sensors on the vehicle are able to recognize the changing quality of the road surface, the load condition and the driving style.
The electronic system determines the most favourable damper setting and transmits the corresponding control signals to the damper modules within only a few milliseconds, so that the optimum setting is adopted all the time. The system works so quickly that the passengers never have the impression of too soft damping, although the softest and most comfortable setting is selected predominantly.