Automotive Industry Trends
Occupant Safety Systems
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According to National Safety Council statistics, motor vehicle crashes are the leading cause of death between the ages of 1 and 33 in the U.S. There is a death caused by a motor vehicle crash every 12 minutes and a disabling injury every 14 seconds. These crashes, injuries, and fatalities are the nation's largest public health problem.
Automotive occupant safety systems have been evolving for the past 20 years to reduce the number of injuries and deaths caused in automobiles. Initially, individual passive devices and features such as seatbelts, airbags, knee bolsters, crush zones, etc. were developed for saving lives and minimizing injuries when an accident occurred. Today, heightened industry and consumer safety concerns, and increased government regulations strive to provide maximum protection to vehicle occupants under any condition.
Modern electronics are making a variety of contributions towards increasing driving safety. Occupant safety systems, including sophisticated airbag and sensor products, evaluate crash severity and monitor occupant characteristics for the appropriate deployment of restraint devices. Products include electronic satellite sensing, sensing and diagnostic modules, seat position sensing, occupant mass sensing, seat belt usage sensing, rear-facing infant seat detection, and frontal variable output airbag modules. Three of the components of the total system are occupant sensing, crash sensing and rollover sensing.
Occupant Sensing
Currently, airbags go instantaneously to deployment, no matter the size and position of the passenger. Using electric-field sensing, the occupant sensing system detects the relative mass and relative position of an occupant through the use of a series of flexible sensor mats embedded in the seat. The sensor mats are connected to an electronic control unit (ECU) at the base of the seat. If the mass is mostly at the front of the seat, as with an infant in a rear-facing infant seat, it will not deploy. The system detects adults as small as 112 lbs (51 kg) to allow the passenger airbag to safely deploy.
Occupant sensing not only detects the size classification of passengers, but it also will detect the "out of" (passenger's) position to suppress the airbag. This weight-based, "smart" deployment will help automakers meet the recently announced U.S. Federal Motor Vehicle Safety Standard (FMVSS) 208, which requires airbags that are more effective for a broader range of occupant weights. Beginning in 2004, 35% of each manufacturer's fleet sold in the U.S. must be equipped with advanced airbag systems, with the number increasing to nearly 100% by 2006.
Crash Sensing
The severity of a collision can be measured by the advanced crash sensing system, which is provided by sensors mounted on the front and sides of the vehicle. Crash sensing systems use radar, laser and/or ultrasonic sensors to detect potential impact situations. The sensing system is typically a single ECU to measure the severity of the impact, and provide deployment signals to the appropriate squibs.
Occupant sensing systems are required to discriminate the severity of the crash event in the first milliseconds of an impact. Occupant sensing and crash sensing together will control airbag deployment, releasing the airbag in what is termed a "multi-stage" deployment or suppression and provide less threatening airbag protection for infants and children.
Rollover Sensing
Rollover sensing will initiate the required safety measures when internal vehicle sensors detect the start of a rollover. It contains a system of sensors that are able to detect the characteristics of a potential vehicle rollover, then directs the vehicle's chassis control systems to engage appropriate countermeasures.
Driven by regulatory mandates and consumer demand in the United States, by 2003, infrared, ultrasonic and transducer-based occupant safety systems will be utilized by automakers across the country. The standards created to develop these intricate systems are being developed by several Standards Developing Organizations (SDOs) including:
Occupant-sensing products are anticipated to generate $3.6 billion or more in new revenue opportunities for automotive manufacturers and suppliers by 2006, according to Strategy Analytics Ltd's recent Automotive System Demand report. The report also forecasts that the systems will grow in sales at a 70% compound annual rate over the next six years.