air bags full report
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airbag is a vehicle safety device. It is an occupant restraint consisting of a flexible envelope designed to inflate rapidly in an automobile collision, to prevent vehicle occupants from striking interior objects such as the steering wheel or window.
PROVIDES PASSIVE RESTRAINT IN OUR CARS
ALTERNATIVE FOR SEAT BELTS
FUTURE OF AIR BAGS
SMART SYSTEMS- WEIGHT SENSORS- TO CLASSIFY PASSENGER
INFRARED OCCUPANT DETECTION- TO DETECT THE DISTANCE OF PASSENGER FROM THE AIR BAG AND TO ADAPT THE FORCE OF DEPLOYMENT
CAPACITIVE REFLECTIVE OCCUPANT SENSING- TO IDENTIFY DISTANCE AND DISCRIMINATE BETWEEN HUMAN AND GROCERIES
UPDATED SENSORS- HELPS PASSENGERS TO GAIN MAXIMUM FROM AIR BAGS
THE AIR BAGS (ARE OF GREATER IMPORTANCE IN TODAYS VEHICLE SINCE SAFETY OF HUMAN LIFE IS OF PRIOR IMPORTANCE. AS THE COUNT OF AUTOMOBILES ARE INCREASING PROBABILITY OF ACCIDENTS IS ALSO MORE .FOR A SAFE RIDING AND FOR SAVING THE PRECIOUS LIFE SAFETY BAGS MUST BE IMPLEMENTED. LETS HOPE AUTOMOBILE MANUFACTURERS IMPLIMENT THE SAME SINCE THE SAFETY FOR LIFE IS INEVITABLE
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The present topic is about safety airbags in cars. No safety device has consumed more attention and resources than the airbag. It is known with high confidencee that when a crash ours , the presence of airbag reduces fatality risk to drivers.
Airbags are subject of serious government and industry research . My seminar and presentation takes you to the history, devolopement and working aspects of airbag.
For years, the trusty seat belt provided the sole form of passive restraint in our cars. There were debated about their safety, especially relating to children. But over time, mush of the country adopted mandatory seat-belt laws. Statistics have shown that the use of seat belts has saved thousands of lives that might have been lost in collisions.
Air Bags have been under development for many years. The attraction of a soft pillow to land against in a crash must be very strong â€œ the first patent on an inflatable crash-landing device for airplanes was filed during World War II. In the 1980â„¢s the first commercial air bags appeared in automobiles.
Since 1988, all new cars have been required to have air bags on both driver and passenger sides (Light Trucks came under the rule in 1999). To date, Statistics show that air bags reduce the risk of dying in a direct frontal crash by 30 percent. Newer than steering Wheel mounted or Dashboard-mounted bags, but not so widely used, are seat-mounted and door mounted side air-bags. Some experts say that within the nest few years, our cars will go from having dual air bags top having six or even eight air bags. Having evoked some of the controversy that surrounded seat-belt use in its early years, air bags are the subject of serious government and industry research and tests.
THE BASICS OF AIR BAGS
Before looking at specifics, letâ„¢s review our knowledge of the laws of the motion. First, we know that moving objects have momentum (the product of the mass and velocity of an object. Unless an outside force acts on an object, the object will continue to move its present speed and direction. Cars consist of several objects, including the vehicle itself, Loose objects in the car and, of course, passengers. If these objects are not restrained, they will continue moving at whatever speed the car is traveling at, even if the car is stopped by a collision.
Stopping an objectâ„¢s momentum requires force acting over a period of time. When a car crashes, the force required to stop an object is very great because the carâ„¢s momentum has changed instantly while the passengersâ„¢ has not much time to work with. The goal of any supplemental restraint system is to help stop the passenger while doing as little damage to him or her as possible.
What an air bag wants to do is to slow the passengersâ„¢ speed to zero with little or no damage. The constraints that it has to work within are huge. The air bag has the space between the passenger and the steering wheel or dashboard and a fraction of a second to work with. Even that tiny amount of space and time is valuable, however, if the system can slow the passenger evenly rather than forcing an abrupt halt to his or her motion.
DEVELOPMENT OF AIR BAGS
The idea of using a rapidly inflating cushion to prevent crash injuries has a long history. The first patent on an inflatable crash-landing device for airplanes was filed during World War II.
Early efforts to adapt the air bag for use in cars bumped up against prohibitive prices and technical hurdles involving the storage and release of compressed gas.
Â¢ If there was enough room in a car for a gas canister.
Â¢ Whether the gas would remain contained at high pressure for the life of the car.
Â¢ How the bag could be made to expand quickly and reliably at a variety of operating temperatures and without emitting an ear-splitting bang.
They needed a way to set off a chemical reaction that would produce the nitrogen that would inflate the bag. Small solid-propellant inflators came to rescue in the 1970â„¢s.
In the early days of auto air bags, experts cautioned that the new device was to be used in tandem with the seat belt. Seat belts were still completely necessary because airbags worked only in front-end collisions occurring at more than 6 Kmph. Only Seat belts could help in side swipes and crashes (Although side-mounted air bags are becoming more common now), rear end collisions and secondary impacts. Even as the technology advances, air bags still are only effective when used with a lap/Shoulder seat belt.
MAIN PARTS OF AIR BAG
There are three parts to an air bag that help to accomplish this feat:
3. Inflation system
The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.The powdery substance released from their sir bag, by the way, is regular cornstarch or talcum powder, which is used by the air bag manufacturers to keep the bags pliable and lubricated while theyâ„¢re in storage.
The sensor is the device that tells the bag to inflate. It works with the control module to discriminate between crash and non-crash events. These sensors measure the severity of the impact. Inflation happens when there is a collision force equal to running into a brick wall at 16 to 24 Km per hour. They are setup so that sudden negative acceleration will cause the contacts to close, telling the control module that a crash before airbag deployment.
The air bagâ„¢s inflation system reacts sodium azide(NaN3) with potassium nitrate (KNO3) to produce large volume of nitrogen gas. Hot Blasts of the nitrogen inflate the air bag from its storage site up to 322Kmph. A Second later, the gas quickly dissipates through a tiny holes in the bag, thus deflating the bag so you can move.
CONSTRUCTION OF AIR BAGS
Airbag are assemblies consisting of the airbag (made of Nylon), inflator modules and sensor housing, electrical connectors (Clock spring), airbag retainer and the cover. The driverâ„¢s side bag is mounted in the center of the steering wheel as shown in fig. 1.
Fig. 1 Driverâ„¢s side bag
Ball and Magnet Type Sensor
Fig. 2 Ball and Magnet Type Sensor
Spring and Roller type
Fig. 3 Spring and Roller type
By function, there are 2 types- Impact sensors and safing sensors. The Forward sensors are located in various locations forward of the passenger compartment. Some are located inside the fenders, some are on the cowl, and some are attached to the core support in front of the radiator.
Rear Sensors are also known as safing sensors as their functions is to determine that a crash has occurred. Rear safing sensors are located in various locations in the passenger compartment depending on the manufacturer. Some are integrated with the control/Diagnostic Module.
The Rear safing sensor must close before the forward sensors to avoid airbag deployment in cases where the impact is not severe enough to cause deployment. When the vehicle is parked with ignition off deployment is very unlikely because there is no power to the circuits for deployment this means that someone can hit your car and sound the alarm but not deploy the airbags.
This is a diagram of a typical inflator assembly behind the steering wheel.
Fig. 4 Inflator assembly
When the control Module activates the airbag assembly, an electric current is sent to the detonator, which ignites the sodium azide pellets. When it burns, it releases nitrogen gas very quickly and in large quantities. This is what inflates the airbag.
Sodium Azide is Rocket fuel. Sodium azide is a solid propellant with a very high gas generation ratio. It is very stable in this application.
When Sodium azide burns, its major product is nitrogen gas, which makes up around 78% of the Earthâ„¢s atmosphere. One of the other by-products is sodium hydroxide. This is commonly known as Lye, which is a caustic compound. The quantities produced are very small and present a very small risk of burns. The white powder residue seen after inflation is common cornstarch, used as lubricant for expansion of the airbag. Testing is underway with inflators that release argon gas.
WORKING OF AIR BAGS
Air Bags are designed to inflate in frontal or frontal-angle impacts in which the car strikes an immovable object at more than about 16 Kilometers per hour or another car at twice that speed. After a collision, sensors sense an electric current to an igniter system or, in some cases, to the computerized control unit. This unit evaluates the situation and then sends an electrical impulse to the igniter system. The electric current heats a filament (wire), which then ignites a capsule. The Ignited capsule supplies the heat to ignite gas-generating pellets. In most systems, the pellets are made of sodium azide and produce nitrogen gas when they burn. In other systems, pressurized argon gas is used instead. The gas then expands quickly and inflates the airbag, which then breaks through a plastic cover in the steering wheel or, the dashboard on the passenger side. The whole process takes about 0.1 second from the exact moment the crash is detected. The air bag starts to deflate immediately, venting the harmless gas through holes in the back of the bag of the through the fabric itself.
MODERN TYPES OF AIR BAGS
Curtain airbags are airbags that inflate in front of vehicle windows to provide passengers better head and neck protection. The curtain airbags are part of new rollover protection system. Most equipped cars will have vertically inflating curtain airbags in the headliner trim just above the windows, while some will have them inflate horizontally from the side pillar between the doors. In some cases, curtain airbags will deploy in a fraction of a second.
Sensors in the side pillar will measure the force of side-impact Collisions. If the sensors measure a strong impact, then the curtain airbags will deploy in a fraction of a second. The curtain airbag will drop straight down over the windows to keep the occupantsâ„¢ heads from striking the window or the intruding nose of another vehicle.
Fig. 5 Inflatable curtain
The system will use sensors that measure tipping rather than impact. These sensors send information to a central module, which will determine if the vehicle is beginning to roll over. If the vehicle is tipping into a roll, the sensors will deploy the curtain airbag. Stored in the headliner above the doors, the cells of the inflatable curtains are inflated in less than 25 thousands of a second in a triggering accident. To avoid stitches from sewing the bag, its cells are woven on the loom directly from the yarn using Autolivâ„¢s one piece-weaving technology. Therefore the bag can remain inflated for several seconds, which is imperative in roll-over accidents. Cool gas will keep it inflated for up to six seconds.
Laboratory tests have shown that the so-called Head Injury Criterion (HIC) can be reduced by approximately 80%. The Inflatable Curtain was developed in cooperation with Mercedes and Volvo.
Car manufacturers selling car with these as standard equipment are Alfa Romeo, Audi, BMW and Volvo.
2. Head-Thorax Bag
The Head-Thorax Side-Impact Airbag has an extension from the regular Thorax Bag that protects the head. It was introduced in 1998 and developed in cooperation with Ford and Renault.
3.Inflatable Tubular Structure (ITS)
The Inflatable Tubular Structure(ITS), the worldâ„¢s first airbag for head protection, was introduced on BMW cars. It consists of a unique nylon tube, installed in the head-liner above the frontal doors that inflates to a diameter of about 15 centimeters(5 inches).
FUTURE OF AIR BAGS
The smart airbag of the future is not just the airbag, but also a redesign of the components in the current airbag system. Features include:
This is a new sensor for the passenger seat to classify the weight and to determine what type of occupant is in the seat, i.e. adult or child.
Infrared Occupant detection
This system will use infrared beams (just like in your TV remote control) to detect the distance the passenger is from the airbag and adapt the force of deployment accordingly.
Capacitive Reflective Occupant Sensing
These sensors will be located in the seat backs and in the dash to identify the distance you and or your passengers are from the dashboard. These sensors will be able to discriminate between a human occupant and inanimate objects like your groceries. This alone will save thousands of dollars in the cases where the driver is the only occupant in the front seat.
The updated sensors will have the capabilities of deploying the seatbelt pretensioners faster, so in a crash situation you will be in the best position to benefit from the airbag deployment.
Centralized electronic Control Unit
The new control units will be able to use all the input from the new sensor technology and through new software deploy what you need when you need it.
Prototype of a Smart Air bag
Fig. 6 Smart Air Bag
The Prototype smart air bag creates a weak electric field. Antennae located under fabric or in the seat cushion measure the field and instantly update the airbag controller about the size and position of the occupant.
When you are involved in a frontal collision somewhere in the neighborhood of at least 20 kmph, a number of things happen very quickly. The sudden deceleration of you vehicle causes 2 sensors to send an electrical signal; to the diagnostic module. The diagnostic module self tests to confirm that a crash event is taking place, and then it allows the signal to trigger the airbag deployment.
Below is an illustration of a driver side airbag deployment. The first image is the airbag inflation, the second depicits your contact with the airbag, and the third is your coming to rest in the seat and the deflation of the airbag. This all takes place in about 30 milliseconds.
In fact the entire inflation/deflation cycle takes less than Ã‚Â½ second. The speed of the airbag inflating is around 320 kmph. The vehicle hasnâ„¢t come to a stop at this point, nor hopefully have you lost control of it.
1988 is the first model for depowered bags. Unfortunately these are not standard equipment on all cars.
Driverâ„¢s Side Airbag
The image below shows the parts of the airbag module in the steering wheel. From top to bottom we have the cover, the airbag assembly, the retainer attached to the steering wheel, the steering wheel and the clock spring.
The Clockspring allows the steering wheel to move while maintaining the electrical connection to the airbag module.
Fig. 7 Driverâ„¢s side air bag
The Passenger bag is mounted in the top of the dash on the passenger side of the vehicle.
When you get in your vehicle and turn the key, look at the dash to find your airbag or SRS light.
It should come on for 7-10 seconds and then go out. This tells you all is well with the airbag system.
Â¢ If the light does not come on, have it checked. After all, it could just be a burnt out Light bulb
Â¢ If the light does not go off after this period (usually 7-10 seconds) there is a problem
Â¢ If the Light comes on while you are driving, it also needs attention.
In addition to the front airbags, the car companies are putting airbags in the doors for side impacts that are not covered by the primary airbags.
They are putting them in the seats for the drivers and rear passengers as well. This increases the cost6 as well as the complexity of the systems.
Since 1990 the National Highway Traffic Safety Administration, which is responsible for the Vehicle safety rules and statistics relating to vehicles, found that of 19 drivers killed by airbags, only five of them were wearing seat belts and two of them were determined to be unconscious before the airbag deployed.
Starting with the 1997 model year some automobiles will be available with depowered Airbag modules
Inflators are undergoing redesign toward a hybrid design using argon gas and non-adized initiators.
DISARMING THE AIRBAG
Steps in disarming
Â¢ Disconnect the battery
Â¢ Wait 30 seconds. The air Bag is equipped with a capacitor and itâ„¢s important to make sure that it is completely discharges before continuing. Change the oil while waiting
Â¢ Remove the airbag fuse. The fuse Box is below the driverâ„¢s left knee; it folds down by squeezing on a couple of tabs near the top of the box. Fuse also checks the diagram on the fuse box lid before pulling the wrong one.
Â¢ Drop the sound insulator panel. This is a plastic panel underneath the steering column. It goes: steering column; interior colored panel; black colored panel. The black panel is the one to remove. There are two screws along the top and two finger-wing nuts along the back (one near the accelerator and one behind the emergency brake.)
Â¢ Fastened to the sound insulator panel is a yellow circuit. This is the airbag circuit. To disconnect the circuit, youâ„¢ll first have to remove a green connector Positive Assurance lock which is for safety catch. Both the green catch and the yellow connector are had to pull apart, but hey eventually will give.
Â¢ Thus the bag is disarmed. The only problems is, now the airbag light will be on all the time. The airbag is fastened to the steering wheel with four Torx screws (T-30), accessible from the behind the wheel. They wonâ„¢t come all the way out theyâ„¢re retained. Once you have them all loose, the airbag will try to fall out. The airbag is till connected by one or two wires. The yellow one is the airbag circuit again; it is unplugged the same way as before, except this time the safety catch is blue.
Â¢ Do not store it anyplace, which gets hotter than 130 degrees; do not heat it or apply electricity (even static).
The air bags are of greater importance in todayâ„¢s vehicles since safety of human life is of prior importance. Since the count of automobiles is increasing tremendously on our roads, the probability of accidents is also more. So far a safe riding and for saving the precious life the safety bags must be implemented. Today it is the prevail age of the high class people who own high priced cars. Lets hope every automobile manufacturers implement the same since safety for life is inevitable.
Â¢Leonard Evans, Airbag benefits,airbag costs,journal of
Scince Servicing Society,2003
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DRIVE SAFELYÂ¦Â¦Â¦.WITH AIR BAG SYSTEMS
Taware Sandeep R Jagadale Prashant B.
B.E. (Mech) T.E. (Mech)
S.V.P.Mâ„¢s College Of Engg.
Malegaon (bk), baramati, pune.
Thirst for high-speed vehicle is nowadays becoming trends leading to several accident and casualties. Customers are appreciating air-conditioned and atomized car. Life is precious and is only once; it canâ„¢t be compare with other thing. Awareness about safety in automobile is need of the hour.
Airbag safety system used in modern cars is type of passive safety adapted to safeguard driver and passengers. It activates in milliseconds after collision and is designed to supplement the protection offered by seat belts. Various elements of
Airbag system are inflator, air bag, gas generator, crash sensors, diagnostic monitoring unit, steering wheel connecting coil and indicator lamp. All the components are connected and communicate through a wiring harness.
This paper highlights on air bag system to reduce the risk of dying in a direct frontal and side impact. It also explains about manufacturing, design, types, future technologies (EDR, dual air bag, head bag, side curtain, improved sensors). The benefits, injuries, fatalities of air bag system are discussed.
Use Search at http://topicideas.net/search.php wisely To Get Information About Project Topic and Seminar ideas with report/source code along pdf and ppt presenaion
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• For years, the trusty seat belt provided the sole form of passive restraint in our cars.
• There were debates about their safety, especially relating to children, but over time, much of the country adopted mandatory seat-belt laws.
• Statistics have shown that the use of seat belts has saved thousands of lives that might have been lost in collisions.
• Like seat belts, the concept of the airbag -- a soft pillow to land against in a crash -- has been around for many years.
• The first patent on an inflatable crash-landing device for airplanes was filed during World War II.
• In the 1980s, the first commercial airbags appeared in automobiles
• Since model year 1998, all new cars sold in the United States have been required to have airbags on both driver and passenger sides. (Light trucks came under the rule in 1999.) To date, statistics show that airbags reduce the risk of dying in a direct frontal crash by about 30 percent. Then came seat-mounted and door-mounted side airbags. Today, some cars go far beyond having dual airbags to having six or even eight airbags. Having evoked some of the same controversy that surrounded seat-belt use in its early years, airbags are the subject of serious government and industry research and tests.
• What an airbag wants to do is to slow the passenger's speed to zero with little or no damage. The constraints that it has to work within are huge. The airbag has the space between the passenger and the steering wheel or dashboard and a fraction of a second to work with. Even that tiny amount of space and time is valuable, however, if the system can slow the passenger evenly rather than forcing an abrupt halt to his or her motion
• The bag itself is made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, more recently, the seat or door.
• The sensor is the device that tells the bag to inflate. Inflation happens when there is a collision force equal to running into a brick wall at 10 to 15 miles per hour (16 to 24 km per hour). A mechanical switch is flipped when there is a mass shift that closes an electrical contact, telling the sensors that a crash has occurred. The sensors receive information from an accelerometer built into a microchip
• The airbag's inflation system reacts sodium azide (NaN3) with potassium nitrate (KNO3) to produce nitrogen gas. Hot blasts of the nitrogen inflate the airbag.
How to Work
Airbag Safety Concerns
• Since the early days of auto airbags, experts have cautioned that airbags are to be used in tandem with seat belts. Seat belts were still completely necessary because airbags worked only in front-end collisions occurring at more than 10 mph (6 kph). Only seat belts could help in side swipes and crashes (although side-mounted airbags are becoming more common now), rear-end collisions and secondary impacts. Even as the technology advances, airbags still are only effective when used with a lap/shoulder seat belt.
• Move your seat to the rear as far as possible while still reaching the pedals comfortably.
• Slightly recline the back of your seat. Although car designs vary, most drivers can achieve the 10-inch distance even with the driver seat all the way forward by slightly reclining the back of the seat. If reclining the seat makes it hard to see the road, you can raise yourself up by using your car's seat-raising system (not all cars have this!) or a firm, non-slippery cushion to achieve the same effect.
• Point the airbag toward your chest, instead of your head and neck, by tilting your steering wheel downward (this only works if your steering wheel is adjustable).
For Children Experts agree that the following safety points are important:
• Children 12 and under should ride buckled up in a properly installed, age-appropriate car seat in the rear seat.
• Infants in rear-facing child seats (under one year old and weighing less than 20 pounds / 10 kg) should never ride in the front seat of a car that has a passenger-side airbag.
• If a child over one year old must ride in the front seat with a passenger-side airbag, he or she should be in a front-facing child safety seat, a booster seat or a properly fitting lap/shoulder belt, and the seat should be moved as far back as possible
The Future of Airbags
• Activities aimed at maintaining and improving the lifesaving benefits of airbags are in full swing. New NHTSA-sponsored tests use improved "dummy" injury criteria based on new knowledge and research.
• Until recently, most of the strides made in auto safety were in front and rear impacts, even though 40 percent of all serious injuries from accidents are the result of side impacts, and 30 percent of all accidents are side-impact collisions. Many carmakers have responded to these statistics (and the resulting new standards) by beefing up doors, door frames and floor and roof sections. But cars that currently offer side airbags represent the new wave of occupant protection. Engineers say that designing effective side airbags is much more difficult than designing front airbags. This is because much of the energy from a front-impact collision is absorbed by the bumper, hood and engine, and it takes almost 30 to 40 milliseconds before it reaches the car's occupant. In a side impact, only a relatively thin door and a few inches separate the occupant from another vehicle. This means that door-mounted side airbags must begin deploying in a mere five or six milliseconds!
• Volvo engineers experimented with different ways of mounting side airbags and chose seat-back installation because that protects passengers of all sizes regardless of how the seat is positioned.
• This arrangement allows them to place a triggering mechanical sensor on the sides of the seat cushions under the driver and front passenger.
• This prevents the airbag on the undamaged side of the car from inflating.
• Installing the entire airbag package in the seat-back also offers the advantage of preventing unnecessary deployments that might be caused by collisions with pedestrians or bicycles.
• It takes a collision of about 12 mph (19 kph) to trigger side airbags.
How to Work Side Airbag
• In the effort to develop safer cars, it might seem as if automobile manufacturers will stuff an airbag anywhere it will fit.
• One such recent innovation, the side curtain airbag, has proven to be quite valuable and versatile.
• For several years, the side curtain airbag has earned higher safety ratings for passenger cars and minivans.
• Recently, though, automakers are finding new ways to adapt side curtain technology specifically for niche applications, especially in high-risk vehicles.
• Drivers of convertibles and SUVs, for example, currently enjoy the benefits of side curtain protection and rollover-specific security.
• Curtain airbags can also be especially helpful as sub-compacts come into vogue.
• Though structural integrity of tiny cars is often questioned by consumers and regulators, a new microcar will use curtain airbags to help protect its passengers' necks.
• If curtain airbags prove effective for rear collisions, they could be instrumental in helping improve public perception of small and efficient cars
Benefits of Side Curtain Airbags
• Some curtain airbags are specifically designed to provide protection in a rollover crash, a feature first found on the Ford Explorer [source: Edmunds.
• Airbags with this benefit feature sensors to notice if a rollover is imminent by monitoring whether the vehicle is tilting.
• When the bags deploy, they remain inflated longer than their non-rollover counterparts to compensate for the additional time vehicle occupants are in danger.
• Regular airbags deflate immediately after the impact, usually less than a second after they are deployed.
• Rollover protection curtains, by comparison, remain inflated for several seconds while people are being tossed around inside the vehicle, and are deployed with cold helium to maintain their volume for an extended period of time.
• This feature is most often found on SUVs, which are more prone to rollover incidents because of their higher center of gravity
Seat Belt Airbag
• BMW engineers have chosen door-mounted airbags.
• The door has more space, allowing for a bigger bag that provides more coverage.
• The head airbag, or Inflatable Tubular Structure (ITS), looks a little like a big sausage and, unlike other airbags, is designed to stay inflated for about five seconds to offer protection against second or third impacts.
• Working with the side airbag, the ITS is supposed to offer better protection in some side collisions.
• Another option for head protection in side impacts is the curtain airbag.
• All of this makes it pretty clear that the science of airbags is still new and under rapid development.
• You can expect many advances in this field as designers come up with new ideas and learn from real-world crash data.
• For more information on airbags and related topics, check out the links on the next page.
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“AIR BAGS IN AUTOMOBILES”
Seat belts have been proven to be effective in saving lives and preventing or lessening injuries in automobile accidents. The key to their success, however, is that occupants must use these safety devices. Because seat belts require active use by the wearer, inventors developed passive restraints to ensure driver and passenger safety. The first passive restraints were modifi-cations of seat belts themselves; the belts were coordinated with operations of opening the car doors and starting the au-tomobile, which caused belts built into tracks in the doors to wrap around the driver or passenger when the seat was occu-pied. Concurrently, the airbag was devised as a secondary form of passive restraint during impact.
Because no action by the vehicle occupant is required to acti-vate or use the airbag, it is considered a passive device. This is in contrast to seat belts, which are considered active devices because the vehicle occupant must act to enable them. Note that this is not related to active and passive safety, which are, respectively, systems designed to prevent accidents in the first place and systems designed to minimize accidents once they occur. For example, the car's Anti-lock Braking System will qualify as an active-safety device while both its seatbelts and airbags will qualify as passive-safety devices. Further termino-logical confusion can arise from the fact that passive devices and systems — those requiring no input or action by the ve-hicle occupant — can themselves operate in an active manner; an airbag is one such device. Vehicle safety professionals are generally careful in their use of language to avoid this sort of confusion, though advertising principles sometimes prevent such syntactic caution in the consumer marketing of safety features.
Various manufacturers have over time used different terms for airbags. General Motors' first bags, in the 1970s, were mar-keted as the Air Cushion Restraint System(ACRS). Common terms in North America include Supplemental Restraint System(SRS) and Supplemental Inflatable Restraint (SIR); these terms reflect the airbag system's nominal role as a supplement to active restraints, i.e., seat belts.
An American inventor, John Wenrick, a retired industrial engineer, designed the original safety cushion for automotive use in 1952 at his kitchen table. His patent lasted only 17 years - long before mainstream automotive usage.
Dr. David S. Breed, invented and developed a key component for auto-motive use: the ball-in-tube inertial sensor for crash detection. Breed Corporation then marketed this innovation first in 1967 to Chrysler. A similar "Auto-Ceptor" crash-restraint, developed by Eaton, Yale & Towne Inc. for Ford was soon offered as an automatic safety system in the USA, while the Italian Eaton-Livia company offered a variant with localized air cushions.
Airbags for passenger cars were introduced in the United States in the mid-1970s, when seat belt usage rates in the country were quite low. Ford built an experimental fleet of cars with airbags in 1971, followed by General Motors in 1973 on Chevrolet vehicles. The early fleet of ex-perimental GM vehicles equipped with airbags experienced seven fatalities, one of which was later suspected to have been caused by the airbag.
In 1974, GM made the "Air Cushion Restraint System"(ACRS) available as a regular production option (RPO code AR3) in some full-size Buick, Cadillac and Oldsmobile models. The GM cars from the 1970s equipped with ACRS have a driver side airbag, a driver side knee restraint (which consists of a padded lower dashboard) and a passenger side airbag. The passenger side airbag, protects both front passengers and unlike most newer ones, it integrates a knee cushion, a torso cushion and it also has dual stage deployment which varies depending on the force of the impact. The cars equipped with ACRS have lap belts for all seating positions but they do not have shoulder belts. These were already mandatory equipment in the United States on closed cars without airbags for the driver and outer front passenger seating positions.
The automotive industry's first passenger side knee airbag (not sepa-rate) was already used on the 1970s General Motors cars, it was inte-grated in the passenger airbag that had a knee cushion and a torso cushion.
Manufacturers emphasise that an airbag is not, and can not be an al-ternative to seatbelts. They emphasise that they are only supplemental to a seatbelt. Hence the commonly used term "Supplemental Restraint System"(SRS). It is vitally important that drivers and passengers are aware of this. In the majority of cases of death caused by air bags, seat belts were not worn.
Airbags As a Supplemental Restraint System(SRS)
The auto industry and research and regulatory communities have moved away from their initial view of the airbag as a seat belt replace-ment, and the bags are now nominally designated as Supplemental Restraint System (SRS) or Supplemental Inflatable Restraints.
In 1980, Mercedes-Benz introduced the airbag in Germany as an option on its high-end S-Class (W126). In the Mercedes system, the sensors would automatically pre-tension the seat belts to reduce occupant's motion on impact (now a common feature), and then deploy the airbag on impact. This integrated the seat belts and airbag into a restraint system, rather than the airbag being considered an alternative to the seat belt.
In 1987, the Porsche 944 turbo became the first car in the world to have driver and passenger airbags as standard equipment. The Porsche 944 and 944S had this as an available option. The same year also saw the first airbag in a Japanese car, the Honda Legend.
Audi was relatively late to offer airbag systems on a broader scale; until the 1994 model year, for example, the 80/90, by far Audi's 'bread-and-butter' model, as well as the 100/200, did not have airbags in their standard versions. Instead, the German automaker until then relied solely on its proprietary procon-ten restraint system.
During the 2000s side airbags were commonplace on even budget cars, such as the smaller-engined versions of the Ford Fiesta and Peugeot 206, and curtain airbags were also becoming regular features on mass market cars. The Toyota Avensis, launched in 1998, was the first mass market car to be sold in Europe with a total of nine airbags. Although in some countries, such as Russia, airbags are still not standard equipment on all cars, such as those from Lada.
Variable force deployment front airbags were developed to help minimize injury from the airbag itself.
The Citroën C4 provides the first "shaped" driver airbag, made possible by this car's unusual fixed hub steering wheel.
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Seat belts have been proven to be effective in saving lives and preventing or lessening injuries in automobile accidents.
The key to their success is that occupants must use these safety devices. Because seat belts require active use by the wearer,
Inventors developed passive restraints to ensure driver and passenger safety.
The first passive restraints were modifications of seat belts themselves; the belts built into tracks in the doors to wrap around the driver or passenger when the seat was occupied.
Concurrently, the airbag was devised as a secondary form of passive restraint during impact
An American inventor, John Wenrick,a retired industrial engineer,designed the original safety cushion for automotive use in 1952
Dr. David S. Breed, invented and developed A key component for automotive use: the ball-in-tube inertial sensor for crash detection.
Breed Corporation then marketed this innovation first in 1967 to Chrysler.
A similar "Auto-Ceptor" crash-restraint, developed by Eaton, Yale & Towne Inc. for Ford was soon offered as an automatic safety system in the USA,while the Italian Eaton-Livia company offered a variant with localized air cushions.
Various manufacturers have used different terms for airbags.
General Motors‘ first bags, in the 1974s, were marketed as Air Cushion Restraint System (ACRS).
Common terms in North America include
Supplemental Restraint System (SRS) and Supplemental Inflatable Restraint (SIR); these terms reflect the airbag system's nominal
role as a supplement to active restraints, i.e., seat belts used in Automobiles
Airbags As a Supplemental Restraint System(SRS)
The auto industry and research and regulatory communities have moved away from their initial view of the airbag as a seat belt replacement, and the bags are now nominally designated as
Supplemental Restraint System (SRS) or
Supplemental Inflatable Restraints
Variable force deployment front airbags were developed to help minimize injury from the airbag itself.
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