Seats Without Sensors

Key Safety Systems could have an active low-risk-deployment passenger-side airbag that will eliminate the need for seat-embedded occupant position sensors in cars by '07, thanks to the use of ticker-tape-like polyester sensor strips.

Key (formerly Breed Technologies Inc.) is in talks with auto makers in Asia, Europe and North America about supplying the component to future vehicle programs.

One OEM is looking at fitting the airbag on a vehicle that will bow in mid-2006 as an '07 model, the supplier says.

“This is one of those products that as soon as it hits the market, there is going to be widespread adoption,” Robert Block, vice president-engineering and program management, North American Airbag & Inflator, tells Ward's in an interview at the company's headquarters in Sterling Heights, MI.

He says the integrated system will save auto makers $25 to $40 vs. occupant classification systems now on the market that use seat-mounted sensors to determine if the passenger seat is occupied and, if so, the size and weight of the occupant.

Project Manager Brian Ford says the system weighs a fraction of an ounce less than conventional devices.

It also reduces complexity by swapping the conventional distributed system with one that is directly integrated into the airbag module.

Key's new airbag — dubbed TickerTape Airbag (TTAB) — uses four strands of black-and-white blocked sensor tape sewn into the airbag as the eyes and the voice box of the system.

As the airbag deploys, the strands pass through sensors that read the speed at which the tape is being unwound.

When tape deployment begins to slow down, indicating the bag has hit an object, a microprocessor decides within 60 microseconds (one-tenth the time it takes the human eye to blink) how much gas to continue pumping into the airbag at what speed based on passenger information passed along by the sensor tape.

TTAB works as an infinitely variable airbag deployment mechanism that adjusts airbag size based on the size and position of passengers and severity of the crash, Ford says. Therefore, it potentially could prove to be a much more effective life-saving device once real-world data is collected.

Unused gas is diverted to a neutral location, such as beneath the dash, and when the tape senses an immovable object, such as a child seat, it will deflate immediately.

Block says TTAB does away with occupant-sensing devices hidden in the seat that often complicate vehicle development programs, such as when slight changes made in seat size or positioning force the entire occupant classification system to be reprogrammed and retested.

TTAB can be programmed early and is not affected by changes made to the vehicle's interior.