In a groundbreaking advancement for automotive safety, ZF LIFETEC introduces the Pre-Crash Dual Stage Side Airbag (Dual Stage SAB), a two-stage airbag system that utilises the critical milliseconds before an unavoidable collision to create valuable space and better protect vehicle occupants.
The Dual Stage SAB pushes the occupant toward the centre of the vehicle before a side impact, increasing the crumple zone. The innovative system triggers its first stage approximately 200 milliseconds before a collision, pushing the occupants a few centimetres inward, away from the expected point of impact. This pre-crash function creates additional space, allowing the second stage of the airbag to deploy more effectively during the collision, thereby maximising its protective capabilities.
Addressing Deadly Side Collision Risk
According to Euro NCAP, side collisions constitute about a quarter of all accidents in Europe and are the second leading cause of death and serious injury. The limited crumple zone in side impacts often leads to severe cabin deformation, resulting in significant head and chest injuries. Side impacts can occur not only in collisions between vehicles but also in scenarios such as pole impacts, where cars collide with trees, pillars, or lamp posts after skidding sideways.
Critical Role Of 60 Millimetres
“We are developing the Pre-Crash Dual Stage Side Airbag because we are convinced that in the event of a side impact, the milliseconds before an unavoidable crash are a major safety advantage,” explains Harald Lutz, Senior Vice President Global Engineering at ZF LIFETEC. “Our pre-crash function offers the opportunity to create valuable space that the subsequent side airbag can use for optimum protection,” he added.
ZF LIFETEC's system leverages the vehicle's existing signal acquisition system, enabling seamless integration into the sensor infrastructure. Upon detecting an unavoidable collision, the first stage of the Dual Stage SAB triggers 200 milliseconds before the crash, moving occupants approximately 60 millimetres inward. This initial action ensures that the second stage of the airbag and other restraint systems, like belt tensioners, can deploy with enhanced effectiveness.
Innovative Dual-Inflator Mechanism
The Dual Stage SAB employs two inflators to manage the two-part air cushion. A hybrid inflator positions the airbag and fills the pre-crash chamber of around 20 litres, which slowly inflates over 30 milliseconds to gently move occupants away from the impact. An exclusively pyrotechnic inflator then rapidly fills the 18-litre second chamber within ten milliseconds post-impact, offering robust protection against intruding vehicle parts. To avoid pressure conflicts, the pre-crash chamber vents through a trigger flap, allowing the second chamber to expand fully and provide optimal protection.
The Pre-Crash Dual Stage Side Airbag has demonstrated its effectiveness in multiple tests, including sled tests focused on complex pole impact scenarios. ZF LIFETEC continues to refine the system, ensuring it accommodates various occupant sizes and seating positions, such as the comfort position during highly automated driving.
Versatility Across Vehicle Classes
Integrated into the seat, the Dual Stage SAB can be implemented across all vehicle classes, provided the necessary pre-crash sensor technology is available. “The Euro NCAP Roadmap 2030 already lists pre-crash functionalities. It is foreseeable that cars equipped with our technology will receive a corresponding plus in the rating,” said Lutz.
The technology company’s Pre-Crash Dual Stage Side Airbag represents a significant leap forward in automotive safety. By utilising the critical milliseconds before a collision to create additional space, this innovative system enhances occupant protection and sets a new standard for side impact safety. As it continues to develop and refine this technology, the future of vehicle safety looks promising, with greater protection and fewer injuries in side collisions.
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