ZF Demos External Airbag for Side Impacts

ZF Friedrichshafen AG is developing an external airbag to enhance vehicle occupant safety during side impact collisions.

The supplier, which demonstrated a prototype system this week in Memmingen, Germany, aims to commercialize the technology five years from now. ZF has been developing the technology for three years.

Simulation tests show external airbags can reduce penetration of an intruding vehicle by as much as 30%. This can lessen injury severity to occupants in such accidents by 40%.

The airbag deploys from the underbody to cover the crumple zone between the A- and C-pillars. ZF says the system is at least five times the size of an interior driver-side airbag. Three inflators are used to deploy the bag evenly at a rate of 1.1 bar (16 psi)—three times the level of interior units—to better absorb the full heft of the striking vehicle. Total system weight is about 6 kg (13 lbs).

Using a mix of cameras, radar and lidar, the system detects impending accidents and deploys the airbag in less than 100 milliseconds prior to a side impact. ZF notes that such accidents accounted for one-third of road fatalities last year in Germany.

ZF says advanced sensors can reliably recognize an unavoidable accident and minimize cases in which an airbag deploys when no impact occurs, according to the supplier. ZF says it system would deploy in more than 99% of relevant side impacts compared with about 80% for current-generation sensors.

The same next-generation sensors would be used to coordinate interior restraints to maximize the efficiency of the overall safety system, ZF says. This includes interior airbag deployment and adjusting seatbelt tension.

ZF notes that its airbag system also would reduce the impact force on the striking vehicle. If pedestrians or other objects are too close to the vehicle, the external airbags would not deploy.