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Safety, Occupant safety – Mercedes-Benz E-Cabriolet 2015 User Manual

Page 63

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HazardousWaste/Perchlorate/

index.cfm.

Method of operation

During the first stage of a collision, the

restraint system control unit evaluates impor-

tant physical data relating to vehicle deceler-

ation or acceleration, such as:

R

duration

R

direction

R

intensity

Based on the evaluation of this data, the

restraint system control unit triggers the

Emergency Tensioning Devices during a fron-

tal or rear collision.
An Emergency Tensioning Device can only be

triggered, if:

R

the ignition is switched on

R

the components of the restraint system are

operational; see "Restraint system warning

lamp" (

Y

page 45)

R

the belt tongue is engaged in the buckle on

the respective front-passenger seat

The Emergency Tensioning Devices in the

rear compartment are triggered independ-

ently of the lock status of the seat belts.
If the restraint system control unit detects a

more severe accident, further components of

the restraint system are activated independ-

ently of each other in certain frontal collision

situations:

R

Front air bags and driver's knee bag

R

Coupe: window curtain air bag, if the sys-

tem determines that deployment can offer

additional protection to that provided by

the seat belt

R

Cabriolet: head bag, if the system deter-

mines that deployment can offer additional

protection to that provided by the seat belt

The front-passenger front air bag is activated

or deactivated depending on the person on

the front-passenger seat. The front-

passenger front air bag can only deploy in an

accident if the PASSENGER AIR BAG OFF indi-

cator lamp is off. Observe the information on

the PASSENGER AIR BAG OFF indicator lamp

(

Y

page 45).

Your vehicle has two-stage front air bags.

During the first deployment stage, the front

air bag is filled with propellant gas to reduce

the risk of injuries. The front air bag is fully

deployed with the maximum amount of pro-

pellant gas if a second deployment threshold

is reached within a few milliseconds.
The activation threshold of the Emergency

Tensioning Devices and the air bag are deter-

mined by evaluating the rate of vehicle decel-

eration or acceleration which occurs at vari-

ous points in the vehicle. This process is pre-

emptive in nature. Deployment should take

place in good time at the start of the collision.
The rate of vehicle deceleration or accelera-

tion and the direction of the force are essen-

tially determined by:

R

the distribution of forces during the colli-

sion

R

the collision angle

R

the deformation characteristics of the vehi-

cle

R

the characteristics of the object with which

the vehicle has collided

Factors which can only be seen and measured

after a collision has occurred do not play a

decisive role in the deployment of an air bag.

Nor do they provide an indication of air bag

deployment.
The vehicle can be deformed considerably,

without an air bag being deployed. This is the

case if only parts which are relatively easily

deformed are affected and the rate of decel-

eration is not high. Conversely, air bags may

be deployed even though the vehicle suffers

only minor deformation. This is the case if, for

example, very rigid vehicle parts such as lon-

gitudinal body members are hit, and sufficient

deceleration occurs as a result.

Occupant safety

61

Safety

Z

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