Optimal side-impact protection is a challenging task, despite the usually much lower
collision speeds. The lateral space available to absorb the collision energy in
the car body is much lower, and there is much less distance between the airbag and
the passenger. Literally, every single inch counts to save lives and prevent serious
injuries.
In the event of a serious side impact, pressure sensors help gain precious reaction
time by measuring the steep and quick increase of pressure within the cavities of
passenger car doors. Even before the accelerometers attached to the airbag control
unit receive a signal indicating a heavy impact, the pressure sensors have determined
that the door cavities have been compressed by an accident. This early detection
gives the airbag control unit additional time to run sophisticated algorithms to
determine the airbag-deployment strategy that will deliver optimal passenger protection.
Hostile conditions in the door cavity complicate the application. Summer and winter
temperatures easily generate temperature differences of more than 100°C, and the
relatively closed, but not completely hermetic, nature of the door allows vapor
and condensation to collect in the space. Add the possibility of freezing humidity—spiced
with salt, spray, and other hostile substances—and vibrations and shocks, and the
challenges become significant. Rigorous qualification test procedures, including
mechanical and chemical tests and sophisticated self-diagnostic functions, prevent
adverse consequences in case of a rare malfunction despite the entire testing rigor.
SMI’s PSS 1 pressure sensor has already been implemented in a range of automotive
models to protect against side impact collisions.
For more information contact SMI sales at sales@si-micro.com.