One knows all about them, the sporty, often low-slung , in which, by driving over a coin, one can feel whether it's heads- or tails up. In the the slightly more moderate versions, the spring suspension and particularly the damping is not that bad at all. Who hasn't experienced butterflies in the stomach when travelling at high speeds in an everyday saloon . The road contact seems very slight, just when one needs it the most. However, who wants to drive permanently with such a hard damping, that ones mother-in-law on the rear seat, has to hold on to her false teeth to stop them from rattling out. Wouldn't it be great, if one could choose (during the trip), and in addition, if the damping could harden itself in a flash should the situation become critical. Just this type of system, with continuous adjustment, is now available, even for the affordable mid-range.
In the above picture, the most important is obvious, the proportional valve, below on the left of the damper pipe. It may also be integrated into the damper piston with an electrical connection above the piston-rod. Here however, because the damper-construction is higher and its effectivity suffers, the external installation is more often found. The same is valid for the rear axle (see above). In this case, in the double-pipe damper, it replaces the base valve and controls the influx and drainage of hydraulic oil to and from the space between. Electronic damping has been around for quite a while. The novelty of this system, is the possibility of enabling almost any number of characteristic curves, and this, in the space of milliseconds, thus, also when yawing in a curve becomes critical, or when the vehicle threatens to overturn. The equipping with sensors and thus, its possibilities, depends on the respective manufacturer. Apart from the ' button, sensors are also possible for the yawing and the vehicle- or superstructure acceleration. Additionally, the movement of the steering wheel and the wheels are important. If one looks at a list of the sensors, one notices the safety-system ESP straight away. In this case there is already networking. It is to be expected, that in the future, the driving safety and the choice of a sportier damping, will be regulated by one control device.
According to the specifications from the manufacturer, it only takes 1-2 milliseconds, before a new adjustment comes into effect. Thereby, at the moment, we'd like to ignore, whether this is done by magnetic valves, more than likely outside- or by so-called linear-motors inside the dampers. The latter can be recognized by the larger diameter of the damper. By the way, lowering the suspension with this sort of equipment is fundamentally a problem. On no account, is changing the springs sufficient. Whether the electronics can and may be adapted, must be checked in each individual case.
Faults in the dampers are first of all looked for in the same way as in conventional dampers, e.g., the question of whether damper-oil is leaking out. Now the cabling of the damper is added to that of the brakes. Thus, care is to be taken when laying them. The construction is of course, thus designed, that the lowest possible current is necessary for the actuator systems, because on the one hand, higher currents strain the on-board electrical system and on the other hand, produce a slower effect.
If a fault has been found, generally speaking, only complete units are replaced anyhow, in the case of complete dampers, of course per axle. Cables are also replaced and not repaired. Because of the unusual position, amid a lot of air- and dirt movement, it is difficult to get a good sealing afterwards. Also if some of the 1 to 2 Amperes are lost as well, one need not be surprized if further defects in the regulation also occur.
The current Mercedes S-class has the innovation, that the road in front of the car is scanned, thus recognizing undulations and ironing them out. The passengers then hardly notice anything at all. The research done by Audi, would like to combine the road-observation system with the navigation-data, to recognize curves beforehand and to adjust the springing/damping so that blindfolded passengers will not even be aware of them. This would be an advantage for those people who tend to suffer from car-sickness. 08/13.