Mercedes-Benz TecDay Real Life Safety - PART IX


Leipzig, Germany, Nov 12, 2008

PRE-SAFE®: Anticipatory occupant protection system reduces the forces exerted on the occupants during accidents by up 40 percent

Mercedes-Benz is the world's only car brand to offer an anticipatory occupant protection system that activates protective measures for the car's occupants if there is an imminent risk of an accident. This multi-award-winning technology, called PRE-SAFE®, is fitted as standard in numerous Mercedes model series and has now been further enhanced by Mercedes-Benz.

The intelligent PRE-SAFE® system takes its lead from nature in that it activates protective measures for the car occupants as a precaution, just as living things react instinctively and search for cover when they are in danger. The aim is to prepare the occupants and the car for an imminent collision so that the seat belts and the airbags can deploy with maximum effect in the event of an impact. What's more, the PRE-SAFE® protective measures are reversible: if the accident is averted, the advance tensioning of the seat belts is halted automatically and the occupants are able to reset the positions of the seats and the sunroof. The anticipatory occupant protection system is then ready for action again straightaway.

Early accident detection is possible because PRE-SAFE® is an intelligent synergy of active and passive safety. It is linked to Brake Assist and the Electronic Stability Program (ESP®), whose sensors detect potentially critical driving situations and send the relevant information to the electronic control units within a matter of milliseconds. PRE-SAFE® also uses these sensor data for anticipatory occupant protection.

PRE-SAFE® celebrated its world premiere in the S-Class in 2002 and has been fitted as standard in the E-Class since 2006.

Like the S-Class, the new E-Class can activate further preventive measures ahead of an imminent accident:

Whereas PRE-SAFE® previously responded to emergency or panic braking – in other words when the driver hit the brake pedal reflexively – the system in the new E-Class can also be activated if Brake Assist PLUS has used the radar system to predict an impending collision and a certain level of deceleration is exceeded when braking. The occupants are prepared for the potential collision by preventive tensioning of the front seat belts and repositioning of the front-passenger seat (if the seat memory function is specified), enabling the seat belts and airbags to offer the best possible protection.

A newly developed multicontour seat ensures that the driver and front passenger are seated even more securely, thereby limiting dangerous whiplash movements by the upper body. If the PRE-SAFE® control unit detects a critical driving situation, it instantly activates the air chambers in the seat cushions and backrests. These then envelope the seat occupants and give them support. Tests at the Mercedes-Benz Technology Center have shown that this PRE-SAFE® function and preventive belt tensioning increases the distance between the shoulder and the inner door lining by up to 40 millimetres at a lateral acceleration of 0.6 g. This enables the sidebag to fulfil its protective function more effectively.

PRE-SAFE® when braking in an emergency
· Driver and front-passenger seat belts are tensioned
· Front-passenger seat* is moved backwards or forwards into the optimum position whilst the cushion angle and backrest inclination are also optimised

PRE-SAFE® when there is a risk of skidding
· Bolsters in the seat cushions and backrests of the multicontour front seats* are inflated
· Side windows at the front and rear are closed
· Sunroof* is closed

* depending on equipment

When installed in combination with DISTRONIC PLUS and Brake Assist PLUS, PRE-SAFE® will also use the information provided by the short-range radar
sensors in the front bumper to tension the front seat belts at the very last moment before an unavoidable collision, thus reducing the forces exerted on the driver and front passenger during the crash. This PRE-SAFE® function is literally the "ultima ratio" of anticipatory occupant protection, since the accident occurs around 200 milliseconds later.

Belt tensioning reduces the forces exerted on the occupants by up to 40 percent

Analyses performed during crash tests show just how important and effective anticipatory occupant protection can be. In the case of belt tensioning, for
example, the precautionary measures mean that the driver and front passenger are held in their seats in the best possible position and so do not move forwards as much in the event of an impact, thus reducing the load exerted on the head and neck area. These tests showed that the head was subjected to around 30 per cent less stress, while the Mercedes engineers recorded a reduction of around 40 per cent in the neck area.

Copyright © 2008, Mercedes-Benz-Blog. All rights reserved.

Bookmark the permalink. RSS feed for this post.

Leave a Reply


Swedish Greys - a WordPress theme from Nordic Themepark. Converted by