New Sensor from Continental Increases Pedestrians' Chances of Survival in an Accident

A novel type of air hose is connected to two pressure sensors and flexibly built into the bumper. This exciting innovation from international automotive supplier Continental fundamentally enhances the protection of pedestrians on the roads.



The sensor reliably recognizes collisions with pedestrians and supplies the safety systems with the information they need to trigger protective measures, said Lorenz Pfau, Passive Safety Application Development, part of Continental's Chassis & Safety Division. Within 10-15 milliseconds of an impact, the active hood of the vehicle is triggered and raised by special actuators. This prevents the pedestrian who has been hit from being severely injured or killed by the impact with the hood and underlying engine block. The extra centimeters provided between the hood and engine create valuable space that can considerably mitigate the consequences of the accident. Every year in Germany, almost 600 pedestrians die in road accidents, equating to one in seven accident fatalities, and around 8,000 people sustain serious injuries. In Europe's capital cities, pedestrians account for almost half of all road deaths.



In a collision, sensors detect the change in pressure in the plastic hose

Until now, fiber optics or acceleration sensors have been used as the sensors for detecting collisions with pedestrians. The pressure hose sensor, which Continental has developed in partnership with Daimler, is a new system offering a range of advantages, for example it is easy to integrate into any vehicle because it can be flexibly adapted to the shape of the chassis. This means that there are no restrictions on vehicle developers if they alter a vehicle's design – as part of a facelift, for example, said Pfau. What's more, the system's technology is extremely robust and offers high resolution and strong signal quality, which boosts the reliability of crash detection.



The crash sensor consists of a hose that is laid across the entire width of the car in its front bumper. The hose is therefore situated directly behind the foam block that is fitted at the front of the vehicle to absorb energy. Standardized pressure sensors are installed at either end of the air-filled pressure hose. The same type of sensor is used to activate side-impact airbags. When a vehicle collides with an obstacle, the resulting pressure exerted on the hose through the front bumper and foam block creates a typical waveform that is detected by the two sensors at the ends of the hose and forwarded to an airbag control unit. Crash algorithms in the analysis software and speed information from the vehicle's information network enable the type of collision to be identified in a hundredth of a second. The signal relay time even allow conclusions to be drawn about the location of the impact, for example the front right-hand corner or the middle of the vehicle. This enables the rapid activation of protection systems, which are most effective in accidents in urban traffic with a pre-crash speed of no more than 55 km/h and a crash speed of between 20 and 30 km/h.



The demands placed on the pedestrian protection system are high because it is expected to significantly exceed, not just fulfill, the legal requirements for pedestrian protection and the standards of the Euro NCAP crash test. This creates particular challenges for the sensor system, which has to be able to reliably detect a collision between the vehicle and a pedestrian – regardless of whether the person is a small child or a grown man. Moreover, the sensors must, with the highest degree of reliability, ascertain 'no-fire' situations in which the protection systems must not be activated under any circumstances. Such situations include bumping the curb with the front spoiler or hitting a small animal.



Pedestrian protection is the most important safety criterion

Last year in Germany, there were around 29,500 accidents in which a pedestrian was hit by a vehicle. Most of these collisions (28,000) took place in built-up areas. A total of 559 people died in these accidents. The German Federal Statistical Office's accident statistics show that another 8,000 or so people were severely injured. An older Europe-wide analysis of the accident data for 2007 found that, of the approximately 1,600 people killed in traffic accidents in European capital cities, almost half (43 percent) were pedestrians. In the Euro NCAP crash test, which is mandatory for all new vehicle models, pedestrian protection has a 20 percent weighting in the overall assessment, while adult occupant protection accounts for 50 percent, child occupant protection for 20 percent, and assistant systems, electronic stability control (ESC), and seat belt reminders for 10 percent. For a vehicle to receive five stars, the highest Euro NCAP category, it must also achieve 60 percent of the maximum points available for pedestrian protection. Particular importance is given to protecting the head after a collision.