MB CL-Class In Depth

Press Release

Safety:
Sensors for situation-related occupant protection

• Precise detection of accident severity by up-front sensors
• Adaptive airbag activation geared to the weight of the front pas-senger
• Windowbags also activated during a roll-over

For model year 2003 Mercedes-Benz is supplementing the efficient occupant protection systems in the CL-Class with new developments which reflect the latest accident research findings and enable the airbags, side-bags, windowbags and belt tensioners to function as the situation requires. With its adaptive front passenger airbag, which inflates in two stages depend-ing on the severity of an accident, the Mercedes CL-Class Coup?????????????????? has already been the trendsetter for situation-related occupant protection in its vehicle class since 1999. The engineers in Sindelfingen have now optimised this technology with newly developed up-front sensors located at the front end. Owing to their forward position these are able to assess the severity of an impact even sooner than the crash sensor on the transmission tunnel. As a result the airbag control unit can shorten the time lapse between the impact and activation of the belt tensioners, and control the two-stage front passenger airbag even more precisely. During a minor frontal collision only one chamber of the two-stage airbag gas generator is triggered, inflating the airbag to a lower internal pressure. If the control unit recognises a severe frontal collision by virtue of the up-front sensors, it also activates the second chamber of the gas generator approx. five to fifteen milliseconds later. This inflates the airbag to a higher pressure and provides a level of protection suited to the severity of the accident. Measuring membrane in the front passenger seat cushion In addition to accident severity the airbag computer also takes the body-weight of the front passenger into account when activating the airbag on the passenger side of the instrument panel according to the situation. A special measuring membrane in the seat cushion makes this possible. It enables the bodyweight of the front passenger to be classified into one of four categories, so that even during a less severe accident, for example, both airbag stages can be activated to give a heavy front passenger the best possible protection. Conversely this individual weight classification could mean that in the case of a lighter front passenger, the second airbag stage would only be activated if the impact is very severe. The new measuring membrane is a further development of the seat occupancy recognition system developed by Mercedes-Benz a few years ago. This ensures that the airbag, belt tensioner and sidebag on the front passenger side are automatically deactivated if the front passenger seat is unoccupied. In this way the adaptive system helps to keep repair costs down following an accident. New roll-over sensor for windowbag activation Activation of the windowbags and belt tensioners during a roll-over is a new feature. Mercedes-Benz has equipped the CL-Class with a special sensor which recognises this type of accident and transmits its data to the control unit for the restraint systems within milliseconds. A programme stored in the control unit memory enables the microprocessor to analyse and assess the nature of the accident. If it establishes that the window-bags will potentially provide additional occupant protection during an impending roll-over, the large air cushions along the vehicle sides are activated within just 25 milliseconds.