2005 Mercedes SLK-Class

Safety

The new SLK-Class reaps the benefits of the progress that has been made: the safety technology on board the sporty roadster is in line with the very latest findings from the field of accident research, and sets new benchmark standards for this vehicle segment.

The Mercedes concept centres around restraint systems capable of adapting to different types of collision. The result is a further decrease in the loads placed on occupants in the event of a severe collision, as well as optimisation of the protective functions triggered following more moderate collisions. It is in this key aspect that the new SLK Roadster differs noticeably from its predecessor, which was itself deemed to be one of the safest sports cars on the road. On the new model, both the driver and passenger airbags feature two-stage operation, as do the new two-seater’s belt force limiters. This means that the systems are deployed in such a way that they are able to offer the greatest possible protection for the situation at hand.

Restraint system: two-stage airbags and belt force limiters

The driver’s airbag is fitted with a two-stage gas generator: in the event of a minor impact at the front, the control unit only ignites the first stage and the airbag inflates more gently. Should the control unit detect a severe frontal collision, however, it deploys the second stage of the gas generator after a delay of some 5 to 15 milliseconds. As a result, the airbag inflates at a higher pressure to provide the driver with the level of protection required in a collision of this severity.

The airbag on the passenger side operates on precisely the same principle, as well as incorporating brand new technology which further improves the way in which the airbag inflates evenly to cover a wide area. In addition to this, the initial pressure increase of the two-stage generator is reduced meaning that the airbag inflates even more gently. This shows just how much consideration Mercedes engineers have given to the fact that children are often seated in the front passenger seat, where the newly developed airbag now offers them even more protection.

The belt force limiters, which make up part of the standard specification of the new SLK-Class, are also able to adapt to the severity of the collision. Should the control module detect a high impact load, it will reduce the restraining force acting on the belt strap after just a short time; as a result, more of the seat belt strap will be fed out and the airbag will be able to cushion the seat occupant more effectively.

Head/thorax airbag: new air cushion integrated into the seat backrest

Mercedes-Benz is also equipping the new SLK-Class as standard with the newly developed head/thorax sidebags which have already debuted in the top-of-the-range SL-Class sports cars. They are accommodated in the backrests of the seats where they are positioned between the sturdy magnesium frame and the cushion holder. Following a side impact, the head/thorax airbag transforms into an asymmetrically shaped cushion in a matter of just 30 milliseconds, with the top edge reaching high above the seat when the airbag is fully inflated. This reduces the risk of the occupant’s head colliding with either the side window or any objects that penetrate the interior of the vehicle, regardless of the occupant’s seating position.

The middle of the head/thorax airbag slides between occupant and door in the event of an impact from the side or the vehicle rolling over, so that the chest area is also cushioned.

Sensor system: upfront sensors enable quick detection of accident severity

The swift, adaptive response of the restraint system is made possible by a highly advanced sensor system. In the event of a head-on collision, fast response is taken care of by two extra upfront sensors. Their remote positioning on the radiator cross member in the front end of the SLK body enables them to detect the severity of a collision even earlier and with greater accuracy than the central crash sensor on the transmission tunnel. The information from the upfront sensors is used by the electronic control module to shorten the time that elapses between the moment of impact and the deployment of the belt tensioners, to adapt the operation of the belt force limiters to the severity of the collision and to trigger the airbags both earlier and in two stages, depending on the situation.

Rapid activation of the head/thorax airbags in the seat backrests is the task of two additional satellite sensors positioned on the outer edges of the bodyshell’s seat cross members which work together with the central crash sensor.

Quite apart from this, the new SLK-Class is also equipped as standard by Mercedes-Benz with a roll-over sensor, which reliably recognises this type of accident and relays its data to the restraint systems’ central control module. In response to this signal, the micro-computer activates the belt tensioners and the head/thorax sidebags in the SLK seats, regardless of whether the vario-roof is open or closed.

Still to be found on the list of standard equipment for the SLK-Class are a sensor pad in the passenger seat which detects whether the seat is occupied, as well as the in-house-developed automatic child seat recognition facility. The child seat recognition facility comprises special aerials in the seat cushion which exchange data with the transponders that are fitted in the base of child seats from the Mercedes accessories range. Using this data, the central control module is capable of detecting when a child seat has been fitted, causing it to deactivate the airbag on the passenger side, as deployment of the airbag could otherwise increase the risk of injury.

Corrosion protection: fully galvanised body

To equip the SLK with long-term corrosion protection, the entire bodyshell is galvanised. In addition, some of the metal panels are treated to an additional organic coating on both sides which also contains rust-inhibiting zinc pigments. All the most vulnerable structural sections of the bodyshell are also protected with a cavity-fill preserving agent. A large area of the underbody is made from plastic so Mercedes engineers were able to dispense with conventional PVC underseal, a potential environmental hazard. The underbody trim panelling protects the bodyshell from stone chipping, wet and dirt. In keeping with all Mercedes passenger cars, the new SLK-Class is also protected by a 30-year MobiloLife warranty.

Engines from 136 to 354 hp...

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