Car WatchingJanuary 20, 2006 By: Barbara G. Goode, Sensors
Savvy sensor buyers watch the automotive market carefully. That's because this cost- and reliability-conscious industry makes tough demands of sensor developers—demands that end up benefiting other applications.
Attendees to the North American International Auto Show (which, all told, runs two full weeks, January 8-22) see a lot of sensors, or at least the benefits that sensors enable. Of course all the basic mechanical processes of cars have been instrumented for years. At this stage, sensors are enabling advanced safety features—in addition to superior comfort.
At a January 8 press conference, Jim Press of Toyota talked of features on the next-generation Lexus LS flagship sedan, including a climate control system that monitors not only cabin temperature, but also occupants' body temperature. "I've been afraid to ask where that sensor goes," he laughed.
Helping Chrysler exceed requirements
Chrysler boasts that its first SUV, the 2007 Aspen, exceeds government and industry safety requirements—a claim they couldn't make without appropriately applying sensor technology. The Aspen uses sensors to keep side-curtain air bags deployed longer in rollovers, while its electronic roll mitigation system monitors vehicle attitude and lateral force to estimate rollover potential (and can trigger engine torque reduction and apply a short burst of full braking to the appropriate wheel). Other sensor-dependent highlights include a rear back-up detection system to "see" items in the driver's blind spot, an advanced multi-stage air bag system that inflates with a force appropriate to impact severity, and brake assist that senses panic braking and takes over for the shortest possible stopping distance. Sensors in the seat belt system include Constant Force Retractors, which release webbing in a controlled manner during severe impact, and pretensioners that remove slack from belts during collision.
Mercedes boasts "active safety"
At the Greater Los Angeles Auto Show (January 6-15), the Mercedes S-Class demonstrated new "active safety" features, including intelligent electronic brake and driver assist systems. The driver assistance system for adaptive cruise control (ACC) maintains distance to the vehicle ahead and ensures the necessary safety interval. The driver sets the desired speed, and once a vehicle appears ahead, ACC is on alert: sensors recognize changes in distance much faster than the driver, and, when a rear-end collision threatens, brakes immediately.
The brake control system uses four pressure sensors in addition to the master cylinder pressure sensor, allowing infinitely variable valves to provide sensitive brake pressures for improved forward and side-to-side dynamics. This, says DaimlerChrysler, translates into shorter stopping distances, barely perceptible braking intervention, and improved driving stability in hazardous situations.
Stay tuned for more on automotive sensor applications and developments. Auto show season is just beginning.
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