Advanced Crash Discrimination using Crash Impact Sound Sensing (CISS)

Current crash sensing technology is mainly based on the measurement of acceleration, aside from the pressure sensing technology for side impact sensing introduced Siemens VDO in 1997. The airbag control unit mounted in the passenger compartment captures vehicle acceleration and calculates the crash detection algorithms. In most of today's systems, the discrimination algorithms are supported by acceleration or air pressure data measured at the crash zone of the vehicle.

Conventional sensor setups have difficulties detecting specific crash situations (e.g. low speed wall versus high speed deformable barrier or angular situations) in a timely manner and with good robustness.

The measurement of “Crash Impact Sound” in the vehicle structure improves the discrimination of today's sensing systems significantly. “Crash impact sound sensing” leads to higher discrimination robustness. Very fast activation times of passive restraints like belt pretensioners and airbags can be achieved and give occupants maximum protection. In addition, the number of sensors in the safety system can be reduced due to fast signal transmission. As an example, two early crash sensors can be reduced to one. The integration of “Crash Impact Sound” sensing into the central control module allows single point sensing for most frontal impacts.