Mercedes accident research 3
The 126 series was launched in 1979 and once again had a strikingly different look. The plastic side protection against bumps was also disrespectfully referred to as 'Sacco boards', after the designer at the time, Bruno
Sacco. But you could also describe them as preventing or mitigating accidents.
The change at the front was a little less noticeable. There were now only bumpers instead of bumper bars. The decisive thing about them was not so much the foamed plastic, which can withstand light touches, but the
bumper bracket underneath, which gave the whole thing even more tolerance when it came into contact with objects.
The whole thing was prompted by new legislation in the USA, which required such a tolerance or rather a springing back into the usual position up to a speed of 8 km/h. Who suffers most from such a regulation? Of
course, the smaller vehicles.
Presumably, the aim was to push vehicles such as the VW Beetle out of the market, which also gave it the large rear lights. Strangely enough, however, the small BMW suffered much more from this ordered cosmetic
change than, for example, the S-Class. At first the bumpers protruded a little, but later they no longer did..
However, the US bumpers on Mercedes and the other brands were equipped with dampers. All you had to do was make sure there was enough space to get out of the way safely. These are elements that have to be
incorporated into the crash zones.
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In the long term, an overall concept is needed that also includes the immediate passive accident protection of passengers. We have not yet mentioned the restraint systems. We have long since moved beyond static and
then dynamic seat belts.
Belt tensioners (pictured above) dominate the scene. They maintain comfort for freedom of movement, but a pyrotechnic tightening is used to eliminate the film reel effect in the winding mechanism and to prevent the belt
from being too loose. The tightening is expressly not intended to cause passengers to retreat into the seats.
This means that despite the ignition, the retraction is designed to be so weak that injuries to the occupants are avoided. The ignition takes place as long as the passengers are not yet affected by the forward movement, i.e.
a very early design with still moderate deformation of the front of the vehicle.
And what does the subsequent collaboration look like? This already leads to overlapping during a crash, the more probable variant in reality. In addition, the wall or corner no longer remains solid throughout, but has
flexible elements in front of it.
The deployment of the seat belts and the airbag, which was added later, must react to this. As this can also result in injuries, a decision is made at the moment of the accident as to whether the measured deceleration
justifies deployment at all.
It even went further, with gradually or even continuously stiffened sheets, so-called 'tailored blanks', also being used in crash zones, which thereby changed their behavior in the event of an accident. This is compensated
for, for example, by having the airbag deploy in two stages.
With all this, however, we must not forget the necessary prevention of accidents. A distinction must be made between an electronically controlled limited-slip differential (ASD), an equally operated all-wheel drive (4MATIC)
on the one hand, and traction slip control on the other.
ASD and 4MATIC can be avoided by a combination of route selection and weather conditions, but not by a vehicle breaking out, for example, due to an urgently needed maneuver. In terms of accident prevention, we
therefore regard ASR.
The system, also known as 'ESP', has now become mandatory in cars. It has become established as an extension of ABS. Originally, a wheel was prevented from spinning further by targeted braking. The system can now
prevent entire undesirable vehicle movements by braking several wheels.
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