ZF has demonstrated a new pre-crash safety system prototype which uses an external side airbag deployed milliseconds before a collision. The OE systems and aftermarket components supplier says it provides an additional lateral crumple zone, which can help save lives and reduce occupant injury severity by up to 40%. To make this possible, ZF has networked the airbags to the vehicle’s sensor systems and developed algorithms that are capable of determining if a crash is imminent and decide whether or not to deploy the airbag.

ZF gave a live demonstration of the prototype for the world’s first pre-crash occupant safety system with an external side airbag in Memmingen. “We highlighted that this safety system has the potential to significantly reduce occupant injury severity in cases of side impact collisions,” explains Uwe Class, Head of the Safe Mobility Systems department, within ZF’s Advanced Engineering team.

The biggest challenge in the development of this system was reliably recognising an unavoidable collision and deploying the external side airbag before the collision takes place. The system has approximately 150 milliseconds to make the decision to deploy the airbag and fill it. The vehicle’s sensors first have to identify a potential impact quickly and accurately. This is possible with connected cameras, radar and lidar. Algorithms within the system software decide whether or not a collision is unavoidable and the deployment of the airbag is both possible and beneficial. If these decisions are all affirmative, the system ignites the inflators to fill the airbag. The airbag, which has a capacity of between 280 and 400 litres (five to eight times the volume of a driver airbag) depending on the vehicle, then expands upwards from the side sill to form an additional crumple zone in the door area between the A and C pillars.

In a side impact collision, the occupants on the side of the impact are at particular risk of serious injuries in the chest area if the passenger cabin is severely deformed. The ZF pre-crash safety system can reduce the penetration of the intruding vehicle by up to 30%, helping to significantly reduce the occupants’ risk of injury.