Automotive Industry Trends

Airbags-The Next Generation

Issue Table of Contents

New Cars with Sense and Sensors Occupant Safety Systems Airbags-The Next Generation World's First Vehicle 'Black Box' Standard Underway at IEEE

Development of "safer" airbags by automakers is moving rapidly. While years of field experience have demonstrated that the previous generation of airbags provided substantial safety benefits to customers, in some cases they also caused serious or even fatal injuries to occupants who were unbelted and/or too close to the deploying air bag - especially children and infants in rear-facing car seats. Manufacturers are actively developing so-called "smart" or "advanced" airbags that are able to tailor deployment based on crash severity, occupant size and position, or seat belt use. These bags should eliminate the risks produced by current air bag designs.

"The first generation of crash sensors allowed for the determination of whether or not the severity of the collision warranted the deployment of an airbag," explains Dr. Chin-Yao Chan 1, a researcher with the Institute of Transportation Studies at the University of Berkeley and Society of Automotive Engineers (SAE) Industrial Lecturer on Sensor Technology. "The next generation of occupant restraint systems, which is equipped with occupant sensing devices, goes beyond this and provides weight sensors under the seat or infrared or ultrasonic sensors or other devices that can capture more information about the type of occupant, the position of the occupant, whether there even is an occupant in the seat, the proximity of the person to the airbag module and so on."

Prior to working with the Institute of Transportation Studies, Chan worked for Breed Automotive Corp. and Automotive Technologies International where he was responsible for the analysis, design, and testing of crash sensors. From there he worked for Forensic Technologies International in the area of accident reconstruction. He has participated in numerous technical investigations of real-world vehicle crashes; he is a co-inventor of a U.S. patent, "Passenger Compartment Crash Sensors," U.S. Patent #5,155,307 and the author of Fundamentals of Crash Sensing in Automotive Air Bag Systems. "Through my affiliation with SAE, I have been able to continue to keep up with the latest information in Sensor technology."

The National Highway Traffic Safety Administration (NHTSA) has a legislative mandate under Title 49 of the United States Code of Federal Regulations Motor Vehicle Safety, to issue Federal Motor Vehicle Safety Standards (FMVSS) and Regulations to which manufacturers of motor vehicle and equipment items must conform and certify compliance. FMVSS208, Occupant Crash Protection, originally specified the type of occupant restraints (i.e. seat belts) required. It was amended to specify performance requirements for anthropomorphic test dummies seated in the front outboard seats of passenger cars and of certain multipurpose passenger vehicles, trucks, and buses, including active and passive restraint or airbags. 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. FMVSS208 specifically requires airbags to be designed that are more effective for a broader range of occupant weights. "FMV208 has brought about several kinds of changes," comments Chan. "Automobile manufacturers and other related industries are suddenly asking themselves; how do we make the airbag sensitive to the type of occupant sitting in the seat? And, how do we deploy them without causing deaths or injuries? So it was just a couple of years ago that changes to the regulations brought about a whole new definition of airbags."

Airbags are, upon activation, filled with gases becoming from inflators. These are essentially devices, which many manufacturers have designed with a smaller amount of propellant. The new generation of inflators is designed to fulfill the performance requirements of smart airbags. The inflators must be capable of providing different levels of energy release for optimal occupant protection. "Accidents are being measured at different energy levels. A major accident would want all the energy the airbag has to be deployed," says Chan. "In a milder accident, you may only want to deploy part of that energy. Therefore, there is a cushion sufficient enough to protect the occupant and yet the person is much less likely to be injured by its deployment."

A number of automakers are presently responding to this need by equipping vehicles with side airbags. These airbags are designed to deploy from the doors, seats, or pillars. Yet, other automakers have gone one step further with side window airbag curtains that drop down from the roofline above the doorframe to protect occupants from intrusion, splintering glass and side window ejection. "The vehicle safety system will always demand a higher and higher standard regardless of how smart the current system is and the intelligent airbag will just become an integral part of a friendly vehicle interior," comments Chan. "So technology is being developed to not only focus on how to make the vehicle interior better able to protect the occupant, but it is focusing on how to equip the exterior of the vehicle with technology such as adaptive cruise control systems and other 'smart' devices that will avoid an accident altogether."

In his current position with the Institute of Transportation Studies, Chan works in the area of Advanced Vehicle Control and Safety Systems (AVCSS), a program within the California Partners For Advanced Transit And Highways (PATH) that focuses on providing vehicle automation to the driver. "PATH applies advanced technology to increase highway capacity and safety, and to reduce traffic congestion, air pollution, and energy consumption," comments Chan. "At AVCSS we work on automating the highway. We do this by deploying technologies that will automate the vehicle with supports from the infrastructure," he explains.

Some of AVCSS's current projects include:

• Vehicle Control Under Abnormal Conditions
• Vehicle Automated Braking Control
• Vehicle Safety Assessment and Safety Enhancement
• Vehicle Fault Diagnosis and Management Through the Use of Sensors and Actuators
• Advanced Vehicle Location
• Communication Systems
• Human Driver Models
• Human-Machine Interactions
• Aerodynamics
• Real System Deployment

"Eventually, highway travel will almost be "train like," whereby people will get on this special vehicle, set a destination via a communication system in the car and the car will drive automatically. The premise is that a computer can make safety-critical judgments much quicker than a human driver," says Chan. "However, the airbag will probably always be needed, as one always has to be prepared in case for any reason the vehicle can't stop in time."

Beginning in FY 2004, dynamic changes in the U.S. market will accompany government mandates for fail-safe occupant sensing devices. To meet these challenges, automakers and suppliers are designing intelligent restraint systems that combine new front and side airbag technologies, occupant sensors, staged airbag deployment, and other vehicle exterior technologies that will keep occupants safer than ever before.