SAE J2074 pdf download

SAE J2074 pdf download.The Air Bag Systems in Your Car “What the Public Needs to Know”.
This SAE Information Report provides basic information about supplemental air bag systems. This report is made available by SAE as a service to the ptlic to explain the value of these systems as they improve the satety of motor vehicles. It also addresses some misconceptions and answers many questions about the operation of air bag systems.
2. References—There are no referenced publications specified herein
3. What is an Air Bag?
3.1 PasslveiAutomatic Crash ProtectIon—On September 11989. all new cars sold in the United States were required to have an automatic crash protection system as standard equipment. Air bags provide the automatic crash protection.
Air bag systems help reduce the seventy of torso, head, and facial injuries. Highway fatality rates have been reduced as air bags are installed on more vehicles. While air bags have significantly improved the safety of motor vehicles, they are not designed nor Intended to be a substitute for safety belts. Safety belts help to secure occupants in all kinds of collisions, and they keep the occupant in position to receive the maximum benefit from an air bag in frontal or near-frontal collisions. This is why air bag systems are usually referred to as supplemenlar restraint systems.
According to the National Highway Traffic Safety Administration (NHTSA). in 1997, 32 213 occupants of passenger vehicles (cars, light trucks, vans, arid utility vehicles) were killed In motor vehicle traffic crashes, 77% of the 41 967 traffic fatalities reported for the year. Among passenger vehicle occupants over 4 years old, safety belts saved an estimated 10 750 lives in 1997.
Research has found that lap/shoulder safety belts, when used, reduce the risk of fatal injury to front-seat passenger car occupants by 45% and the risk of moderate-tO-critical injury by 50%. For light truck occupants, safety belts reduce the risk of fatal iniury by 60% and moderate-to-critical injury by 65%.
Recent NHTSA analyses indicate an overall fatality-reducing effectiveness for air bags of 11%. Research on the effectiveness of child st aety seats has found them to reduce fatal injury by 69% for infants (less than 1 year old) and by 47% for toddlers (1 to 4 years old).
3.2 AIr Bags are Supplemental to Seat Belts—Whether or not your vehicle is equipped with air bags. you must wear a safety belt, Safety belts are an occupant’s primary restraint because they are designed to reduce the risk of injury in most types of crashes, including low-speed-frontal, rear-end, side, rollover, and multiple collisions. In these types of crashes, safety belts help to keep occupants from being thrown from the vehide, arid reduce the chances and severity of contacting the vehicle’s interior. Air bags are designed to supplement the protection offered by safely belts in moderate to severe frontal or near-frontal collisions. However, field data have demonstrated only 10% of all accidents are significant enough to require deployment of air bags. Even in collisions where air bags deploy. it is important that a safety belt be worn to insure that the occupants are in the proper seating position to receive the maximum benefit from both the belts and air bags. Most Injuries from an inflating air bag are minor, such as facial abrasaons and bruises. However, the risk of these injuries can be reduced if an occupant sits back comfortably in the seat and wears a safety belt. For a driver, sitting back in the seat means he or she can still maintain the ability to operate the vehicle and its controls safely.
In a frontal crash, the vehide begins to stop when an impact occurs, but the occupants continue to move forward at the vehiclWs original speed. Unbelted occupants or occupants wearing improperly adjusted belts impact the windshield, instrument panel, or the steering wheel, possibly causing severe inluries. Occupants wearing properly adjusted safety belts are stopped more gradually by the belts as the car stops because the safety belts distribute the vehicle’s energy of motion more evenly across the body. In more severe collisions, however, even belted occupants could contact objects in the vehicle’s interior because their forward motion is so great that they contact the interior before the belts can bring them to a complete stop.
Air bags supplement the safety belts by reducing the chances of such contact with the vehicle’s interior and by distributing the impact more evenly over an occupant’s head and torso. Air bags help absorb the energy of the driver and passenger. Motorists should realize, however, that the use of safety belts is critical to keeping them in position so that the air bags can provide the intended benefit to the occupants in the event of a frontal or near-frontal collision.
Some vehicles are equipped with side air bags to supply additional protection In the event of a side impact. The side impact air bag system supplements the protection offered by the doors and the vehicle structure. The side impact air bag system deploys an air bag from the side of the seat. A side crash of sufficient force will deploy a side air bag.
In addition, some vehicles are equipped with seat belt pretensioners. The seat belt pretensioners remove slack from the seat belts during a collision. The system deploys the seat belt pretensionecs with the air bags. Pretensioners work only once. If they activate in a crash, they will have to be replaced to ensure properation.