SMART Series 451 Service Manual page 19

SN_Typ 451_us.book Seite 18 Freitag, 30. November 2007 1:56 13
Safety concept
Passive safety
The goal of a vehicle's passive safety is to minimize as
much as possible the effects of an accident on the
people involved. Some of the most important aspects
of this are the preservation of the survival space
(rigid passenger cell), high energy dissipation in the
event of an accident thanks to exploitable crumple
zones at the front and rear, and energy-absorbing
restraint systems in the interior.
The passive safety concept includes:
• tridion safety cell consisting of 50% high-strength
steel
• Crash management system (CMS) at the front and
rear, which absorbs energy at low vehicle speeds
and prevents expensive bodyshell damage
• Front end with no major assemblies, for effective
exploitation of the short overhang as a crumple
zone
• Inclusion of the wheels and axles/frame-type
integral support in the crumple zone and for force
application
• Front and rear structures with several impact
planes and large cross sections to transfer and
disperse the crash energy that is generated
• Long forward displacement area for the driver and
passenger with restraint systems adapted to
compensate for the "short" crumple zone
• Sturdy steel seat structures for effective
protection against shifting cargo and for specific
deformation in rear-end collisions
• Side doors made of solid steel frame profiles
including side impact protection
• Safe positioning of the fuel tank in the underfloor
area between the axles
• Deformable steering column to dissipate energy,
prevent intrusion and lengthen the forward
displacement distance in a frontal collision
• Full interior lining to reduce head injuries
18 Introduction of the smart fortwo, Model Series 451
The occupant restraint systems comprise:
• 2-stage driver airbag in steering wheel
• 2-stage top-mounted passenger airbag with
deployment opening on the top surface of the
instrument panel
• Head/thoraxbags in the backrests
• Three-point seat belts with emergency tensioning
retractors, belt force limiters and belt guides on
the backrests
• Seat belt reminders for driver and passenger
• Belt tension sensor on passenger side
• Passenger seat with Weight Sensing System (WSS)
with automatic passenger airbag deactivation for
the corresponding weight classes and airbag OFF
indicator lamp
• Full-length knee guard
• Two frontal acceleration sensors on front
crossmember
• Two satellite sensors on inner side wall in area of
left and right B-pillar
• Restraint systems control unit
1 Driver airbag
2 Passenger airbag
3 Head/thoraxbag
P91.60-3663-00