In Europe, there were close to 43,000 road accident-related fatalities in 2006. Twenty-five percent of these were caused by side impacts. Even higher figures in 2004 provided the catalyst that led the European Union to launch the APROSYS project. Part of this aimed to develop a pre-crash system for vehicles involved in side-on collisions. To do this, a team included Daimler, Faurecia, Continental, Fraunhofer Gesellschaft, the CIDAUT Foundation, TNO Science and Industry and the universities of Warsaw and Lisbon have officially presented the APROSYS project in Valladolid, Spain, on March 6-7.
The system developed for the APROSYS project involves two main parts that address both these issues.
Firstly, a pre-crash sensor system has been integrated into the vehicle body. This is able to predict a collision almost 200 milliseconds before impact and decide whether or not to activate the safety system. This provides the time necessary for an active safety system to be deployed providing the best level of protection possible for occupants.
Secondly, the safety system itself, which was developed by Faurecia's experts in Scheuerfeld, Germany, is designed to reduce structural intrusion into the vehicle by up to 70mm. To achieve this, Faurecia's team developed a system that, once activated, forms a continuous metal tube that runs from the exterior chassis of the door, under the seats and through the opposite door. This allows the energy of the collision to be transferred right across the vehicle thereby reducing the force in the impact zone.
The actuator that makes this system possible involves a breakthrough technology that Faurecia developed with a specialist-partner, the Fraunhofer Institute. Once the pre-crash sensors give the signal, a wire switch made of Shape Memory Alloy (SMA) releases a spring-loaded bolt that effectively extends the metal tube from the seat to the door on each side of the vehicle. Another actuator closes the gap between the door's exterior shell and interior trim. The result is the creation of a continuous metal tube within 60 milliseconds of the initial signal that redirects the forces of the collision away from the b-pillar.
In addition to dramatically increasing the survival space of the vehicle occupant, the system also improves the overall effectiveness of other safety systems such as airbags, which can be deployed more slowly and softly as a result, and seat belts. Through the use of shape-memory alloys, the system is also entirely reversible. This means that, unlike with pyrotechnic systems, it can be rearmed and reused.
"Through the combined research and development efforts of all APROSYS partners, we have come up with a solution that could make a significant difference to road safety," says Eric Zimmerman, Faurecia's APROSYS project leader and Door Safety Manager. "The system we have put together is technologically feasible and, with some further development work, could be seen on the roads within the next five years".
