Automobile airbags like the ones in this Peugeot 306 car, inflate and deflate within a fraction of a second (about 0. The Peugeot 306 is a Small family car built by the French Car manufacturer Peugeot from 1993 to 2002 05 seconds).

An airbag,^[1] also known as an Air Cushion Restraint System (ACRS), or the Supplemental Inflatable Restraint (SIR) (reflecting the airbag system's intended role as a supplement to conventional restraints such as seat belts), is a flexible envelope commonly used for cushioning against hard interior objects (such as steering wheels), in particular for rapid inflation in the case of an automobile collision. A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from A collision is an isolated event in which two or more bodies (colliding bodies exert relatively strong forces on each other for a relatively short time It is a "passive" safety component, rather than an "active" component (that is: it reacts after an accident has happened, rather than helping to avoid an accident in the first instance, like ABS or ESP).

Airbags are one component of a number of complementary components which fall under the 'umbrella' term of Safety Restraint System, also known as Supplementary Restraint System (SRS). Airbags are designed to complement conventional restraints, such as seat belts, and seatbelt pre-tensioners, not replace them. A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from Other additional passive automotive safety features include "anti-submarine" seats, telescopically collapsible steering columns, "brake away" control pedals (accelerator/brake/clutch), toughened and/or laminated glass

The number of lives saved by airbags is hard to pin down. One study, cited below, puts the number at just under 400 per year (6,000 total), and another study indicates that airbags reduce fatalities by 8% when seat belts are worn. Airbags also greatly increase the efficiency of seat-belts, in some cases up to 50%.

History

1975 Buick Electra Limited with ACRS

Since the start of 1994, Ford made airbags standard across their entire range of cars sold in Europe (except for the Maverick which was outsourced from Nissan). Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following The Nissan Mistral is an 4x4 off-roader manufactured by the Japanese Automaker Nissan.

Invention

John W. Hetrick of Newport, Pennsylvania, USA invented the airbag in 1952, and patented his device in 1953. Newport is a Borough in Perry County, Pennsylvania, United States. A patent is a set of Exclusive rights granted by a State to an inventor or his assignee for a fixed period of time in exchange for a disclosure of an Hetrick came up with the idea to help protect his own family using expertise from his naval engineering days^[2]. Throughout the years, the saving of many lives have been attributed to Hetrick's invention, and highlighted in television shows such as Nova on PBS, or his winning of awards such as the Golden Gear award. Nova is a Popular science Television series from the US produced by WGBH Boston The Public Broadcasting Service ( PBS) is a Non-profit Public broadcasting Television service with 354 member TV stations in the There have been devices similar to airbags for airplanes as early as the 1940s, with the first patents filed for those devices in 1958. Overview Fixed-wing aircraft range from small training and recreational aircraft to Wide-body aircraft and military cargo aircraft. Early airbag system origins traces back to air filled bladders. These systems were large and bulky, and primarily consisted of compressed or heated air, compressed nitrogen gas (N₂), freon, carbon dioxide (CO₂), or a mixture of water and potassium (KH₂O). Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Freon is DuPont 's trade name for its odorless colorless nonflammable and noncorrosive Chlorofluorocarbon and Hydrochlorofluorocarbon Refrigerants Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Water is a common Chemical substance that is essential for the survival of all known forms of Life. Potassium (pəˈtæsiəm is a Chemical element. It has the symbol K (kalium from qalīy Atomic number 19 and Atomic mass 39 ^[3]

An American inventor Allen K. Breed then developed a key component for automotive use - the ball-in-tube sensor for crash detection. He marketed this innovation first in 1967 to Chrysler. Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 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,^[4] while the Italian Eaton-Livia company offered a variant with localized air cushions. ^[5]

First automotive applications: an alternative to the seatbelt

Airbags for passenger cars were introduced in the United States in the mid-1970s, when seat belt usage was not prevalent. The United States of America —commonly referred to as the This article is about the Decade 1970-1979 For the Year 1970 see 1970. A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from Airbags were generally considered a convenient alternative to seat belts, while offering similar levels of protection to unbelted occupants in a head-on collision. A head-on collision is one where the front ends of two Ships, Trains, Planes or Vehicles hit each other as opposed to a Side-collision

Ford built an experimental fleet of cars with airbags in 1971, followed by General Motors in 1973 on Chevrolet vehicles. Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following General Motors Corporation ( GM) ( is a multinational automobile manufacturer founded in 1908 and headquartered in the United States. In 1974 General Motors adopted the technology for other brands like Buick, Cadillac and Oldsmobile, and offered dual airbags with two-stage deployment,^[6] and called them "Air Cushion Restraint System". ^[7] The early fleet of experimental GM vehicles equipped with airbags experienced seven fatalities, one of which was later suspected to have been caused by the airbag.

The development of airbags coincided with an international interest in vehicle road safety legislation. Some safety experts cautioned against mandating a particular technical solution, rather than a general occupancy safety standard, which could rapidly date out and might not be a cost-effective approach. Motor manufacturers favoured one standard over another, which could not easily be changed. As countries successively mandated seat belt restraints, there was less emphasis placed on other designs for several decades. ^[5]

Rebirth: supplemental restraint

Car designers have moved on from the initial view of the airbag as a seat belt replacement. Automobile airbags are now designed and marketed as Supplemental Restraint Systems (SRS).

In 1980, Mercedes-Benz re-introduced the airbag in Germany that it had patented in 1971, as an option on its high-end S-Class (W126), which also offered such other exotic options as hydropneumatic suspension. Mercedes-Benz is a German manufacturer of luxury Automobiles Buses coaches and Trucks It is currently a division of the For a complete overview of all S-Class models see Mercedes-Benz S-Class. Hydropneumatic is a type of Automotive suspension system, invented by Citroën, and fitted to Citroën cars as well as being adapted by other car manufacturers In the Mercedes system, the sensors would tighten the seat belts, and then deploy the airbag on impact. The airbag was thus no longer marketed as a means of avoiding seat belts, but as a way to obtain an extra margin of occupant safety.

In 1987, the Porsche 944 turbo became the first car in the world to have driver and passenger airbags as standard equipment. Porsche SE or Porsche ( German, ˈpɔɹʃə is a German manufacturer of automobiles which is majority-owned by the Porsche and Piëch The Porsche 944 and 944S had this as an available option. The 944 is a Sports car built by Porsche from 1982 to 1991 It replaced the 924 as Porsche's entry level model although 924 production continued through This year also saw the first airbag in a Japanese car, the Acura Legend. The Acura Legend, sold as the Honda Legend outside the US, Canada, and parts of China, was a sporty Luxury vehicle sold from

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. AUDI AG, ( Xetra: NSU commonly known as Audi (aˈʊdi is a German Automobile manufacturer which produces Audi branded cars with headquarters The Audi 80 is a Compact executive car produced by the German car manufacturer Audi, from 1966 to 1996 The Audi 100 is a Mid-sized Automobile from Audi (part of the Volkswagen Group) made between 1968 and 1994 Instead, the German automaker until then relied solely on its proprietary procon-ten restraint system. procon-ten (lower case initial "p") (an acronym for Pro grammed Con traction- Ten sion) is a Proprietary

Airbags became common in the 1980s, with Chrysler and Ford introducing them in the mid-1980s; the former made them standard equipment across its entire line in 1990. The 1980s was the decade spanning from January 1 1980 to December 31 1989. Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following

In Europe, airbags were almost unheard of on family cars until the early 1990s. The 1990s collectively refers to the years between and including 1990 and 1999 The first European Ford to feature an airbag was the facelifted Escort MK5b in 1992; within a year, the entire Ford range had at least one airbag as standard. Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following The Ford Escort is a Small family car manufactured by the Ford Motor Company from 1967 to 2003 By the mid 1990s, European market leaders such as Vauxhall/Opel, Rover, Peugeot, Renault and Fiat had included airbags as at least optional equipment across their model ranges. Vauxhall Motors is a British automobile company It is a subsidiary of General Motors Corporation (GM and is part of GM Europe. Adam Opel GmbH (commonly known as Opel) is a German automaker part of General Motors. Rover Group plc was the name that was given by the British government, in 1986 to the state-owned vehicle manufacturer British Leyland or BL For the article about the bicycle manufacturer see Cycles Peugeot. This is about the company for other uses see Renault (disambiguation. Fiat SpA (an Acronym for Fabbrica Italiana Automobili Torino (Italian Automobile Factory of Turin) is an Italian automobile manufacturer By the end of the decade, it was very rare to find a mass market car without an airbag, and some late 1990s products, such as the Volkswagen Golf Mk4 also featured side airbags. Launched in 1997 the Volkswagen Golf Mk4 (or VW Typ 1J) became the biggest selling car in Europe at one point The Peugeot 306 was a classical example of how commonplace airbags became on mass market cars during the 1990s. The Peugeot 306 is a Small family car built by the French Car manufacturer Peugeot from 1993 to 2002 On its launch in early 1993 most of the range did not even have driver airbags as an option. By 1999 however, side airbags were available on several variants.

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 Ford Fiesta is a Supermini car designed by Ford Europe, a subsidiary of Ford Motor Company The Peugeot 206 is a supermini (subcompact car manufactured by the French Automaker Peugeot since 1998 The Toyota Avensis, launched in early 2003, was the first mass market car to be sold in Europe with a total of nine airbags. The Toyota Avensis is a Large family car built in Derbyshire, United Kingdom by Japanese automaker Toyota since the 1998 model year

Airbags become mandatory

On 11 July 1984, the U. Events 911 - Signing of the Treaty of Saint-Clair-sur-Epte between Charles the Simple and Rollo of Normandy. Year 1984 ( MCMLXXXIV) was a Leap year starting on Sunday (link displays the 1984 Gregorian calendar) S. government required cars being produced after 1 April 1989 to have driver's side airbags or automatic seat belts (the automatic seat belt was a technology, now discarded, that "forced" motorists to wear seatbelts). Events 527 - Byzantine Emperor Justin I names his nephew Justinian I as co-ruler and successor to the throne Year 1989 ( MCMLXXXIX) was a Common year starting on Sunday (link displays 1989 Gregorian calendar) Automatic seat belts are Seat belts that automatically close over riders in a Car. Airbag introduction was stimulated by the U. S. DOT. The United States Department of Transportation ( DOT) is a federal Cabinet department of the United States government concerned with Transportation ^[8] However, airbags were not mandatory on light trucks until 1995.

In 1998 dual front airbags were mandated by the National Highway Traffic Safety Administration (NHTSA), and de-powered, or second-generation airbags were also mandated. The National Highway Traffic Safety Administration ( NHTSA, often pronounced "nit-suh" is an agency of the Executive Branch of the U This was due to the injuries caused by first-generation airbags that were designed to be powerful enough to restrain people who were not wearing seat belts.

In the United Kingdom, and most other developed countries there is no direct legal requirement for new cars to feature airbags. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Instead, the Euro NCAP vehicle safety rating encourages manufacturers to take a comprehensive approach to occupant safety; a good rating can only be achieved by combining airbags with other safety features. The European New Car Assessment Programme (Euro NCAP is a European Car safety performance assessment programme founded in 1997 by the Transport Research ^[9] Thus almost all new cars now come with at least two airbags as standard.

Side-impact airbags

Side airbag inflated permanently for display purposes

Side-impact airbags are a category of airbag usually located in the seat, and inflate between the seat occupant and the door.

These are specifically designed to reduce the risk of injury to the pelvis and lower abdomen. Some vehicles are now being equipped with a different types of designs, to help reduce injury and ejection from the vehicle in rollover crashes.

The Swedish company Autoliv AB, was granted a patent on side airbags, and they were first offered as an option on the 1995 model year Volvo 850, and as standard equipment on all Volvo cars made after 1995. Autoliv () is a Swedish-American company with headquarters in Stockholm Sweden, that in 1997 sprung from the merger of the Swedish company Autoliv The Volvo 850 is a Compact executive car produced by Volvo Cars from 1992 to 1997 (sold as 1993–1997 in the U The first 'head protection' airbags were included as standard equipment in the model year 1998 BMW 7-series and E39 5-series. The BMW E38 Automobile platform was the basis for the 1994 through 2001 BMW 7 Series automobiles

In late 1997 the BMW 7-series and E39 5-series were fitted with head side airbags, the "Head Protection System (HPS)". The BMW E38 Automobile platform was the basis for the 1994 through 2001 BMW 7 Series automobiles This is an industry's first in offering head protection to the front seat passengers in side impact collisions. ^[10] This airbag will maintain inflation for up to seven seconds for rollover protection. However, this tubular shaped airbag is replaced by a inflatable 'curtain' airbags for superior protection.

In 1998 the Volvo S80 was first given curtain airbags to protect both front and rear passengers. They were then made standard equipment on all new Volvo cars from 1998. The Volvo Curtain Airbag design is now considered to be superior by most car manufacturers and is the one mostly used; in some cars it has been designed to stay inflated for rollover crashes.

The many SUVs and MPVs have a long inflatable curtain airbag that protects all 3 rows of seats manufactured in recent years. A sport utility vehicle ( SUV) is a generic marketing description for a rugged automotive vehicle similar to a Station wagon but built on a light-truck chassis A minivan, multi-purpose vehicle (abbreviated MPV) people-carrier, people-mover or multi-utility vehicle (shortened

Curtain airbags have been said to reduce brain injury or fatalities by up to 45% in a side impact with an SUV. These airbags come in various forms (e. g. , tubular, curtain, door-mounted) depending on the needs of the application. ^[11]

Motorcycle airbags

In 2006 Honda introduced the first motorcycle airbag safety system on its Gold Wing motorcycle. () is a Multinational corporation, engine Manufacturer and engineering corporation headquartered in Japan. MotorCycle is the title of a 1993 album by Rock band Daniel Amos, released on BAI Records.

Other airbag design

The Citroën C4 provides the first "shaped" driver airbag, made possible by this car's innovative fixed hub steering wheel. The Citroën C4 is a Small family car produced by French automaker Citroën since autumn 2004

Dual-stage airbags

Many advanced airbag technologies are being developed to tailor airbag deployment to the severity of the crash, the size and posture of the vehicle occupant, belt usage, and how close that person is to the actual airbag. Many of these systems use multi-stage inflators that deploy less forcefully in stages in moderate crashes than in very severe crashes. Occupant sensing devices let the airbag control unit know if someone is occupying a seat adjacent to an airbag, the mass/weight of the person, whether a seat belt or child restraint is being used, and whether the person is forward in the seat and close to the airbag. Based on this information and crash severity information, the airbag is deployed at either a high force level, a less forceful level, or not at all.

Adaptive airbag systems may utilize multi-stage airbags to adjust the pressure within the airbag. The greater the pressure within the airbag, the more force the airbag will exert on the occupants as they come in contact with it. These adjustments allow the system to deploy the airbag with a moderate force for most collisions; reserving the maximum force airbag only for severest of collisions. Additional sensors to determine the location, weight or relative size of the occupants may also be used. Information regarding the occupants and the severity of the crash are used by the airbag control unit, to determine whether airbags should be suppressed or deployed, and if so, at various output levels.

Airbags in certain car models deploy twice, for two crashes; it first deploys and deflates, and then re-inflates upon a subsequent collision.

How airbags work

The design is conceptually simple; a central "Airbag control unit"^[12] (ACU) (a specific type of ECU) monitors a number of related sensors within the vehicle, including accelerometers, impact sensors, roadwheel speed sensors, gyroscopes, brake pressure sensors, and seat occupancy sensors. In automotive electronics an electronic control unit (ECU also called a Control unit, or Control module, is an Embedded system that controls one or more An accelerometer is a device for measuring Acceleration and gravity induced reaction forces When the requisite 'threshold' has been reached or exceeded, the airbag control unit will trigger the ignition of a gas generator propellant to inflate a nylon fabric bag extremely rapidly. A gas generator usually refers to a Propellant mixture often similar to a Solid rocket propellant that burns to produce large volumes of Gas. Overview Nylon is a Thermoplastic silky material first used commercially in a nylon- Bristled Toothbrush (1938 followed more famously by The inflated airbag reduces the deceleration experienced by the passenger during the crash. The bag has small vent holes, to allow the propellant gas to be slowly expelled, in a controlled manner from the airbag, as the force of the occupant pushes against it.

The different signals from the various sensors are fed into the Airbag control unit, and this determines the angle of impact, the severity, or force of the crash, along with other variables. Depending on the result of these calculations, the ACU may also deploy various additional restraint devices, such as seat belt pre-tensioners, and/or airbags (including frontal bags for driver and front passenger, along with seat-mounted side bags, and "curtain" airbags wich cover the side glass). A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from Each restraint device is typically activated with one or more pyrotechnic devices, commonly called an initiator or squib. The term "pyrotechnics" can also be used for Fireworks events A squib is a small Explosive device used in a wide range of industries from special effects to military applications The squib activates with a current pulse between 1 to 3 amperes in less than 2 milliseconds. The squib has a fuse-like conductor inside that heats the pyrotechnic material tightly packed around the conductor. When the conductor becomes hot enough, it ignites the pyrotechnic material, which in turn generates hot gas. In a seat belt pre-tensioner, this hot gas is used to drive a piston that pulls the slack out of the seat belt. In an airbag, the hot gas from the squib is used to ignite solid propellant inside the airbag inflater. The burning propellant generates inert gas which rapidly inflates the airbag in approximately 20 to 30 milliseconds. An airbag must inflate quickly in order to be fully inflated by the time the forward-traveling occupant reaches its outer surface. Typically, the decision to deploy an airbag in a frontal crash is made within 15 to 30 milliseconds after the onset of the crash, and both the driver and passenger airbags are fully inflated within approximately 60-80 milliseconds after the first moment of vehicle contact. If an airbag deploys too late or too slowly, the risk of occupant injury from contact with the inflating airbag may increase. Since more distance typically exists between the passenger the instrument panel, the passenger airbag is larger and requires more gas to fill it.

During the crash, the force of the occupant going forward (toward the point of impact) forces the gas out of the airbag through its vent holes, thereby causing it to deflate. It is the deflation of the airbag that provides the cushioning effect to the occupants as they continue to travel forwards towards the point of impact. The airbag's volume and the size of the vents in the bag are tailored to each vehicle type, to dissipate the occupant's energy over time and distribute the deceleration forces across a larger portion of the occupant's body (compared to a seat belt alone).

Front airbags normally do not protect the occupants during side, rear, or rollover accidents. ^[13] Since airbags deploy only once and deflate quickly after the initial impact, they will not be beneficial during a subsequent collision. Safety belts help reduce the risk of injury in many types of crashes. They help to properly position occupants to maximize the airbag's benefits and they help restrain occupants during the initial and any following collisions.

In vehicles equipped with a rollover sensing system, accelerometers and gyroscopes are used to sense the onset of a rollover event. If a rollover event is determined to be imminent, side-curtain airbags are deployed to help protect the occupant from contact with the side of the vehicle interior, and also to help prevent occupant ejection as the vehicle rolls over.

Triggering conditions

Airbags are designed to deploy in frontal and near-frontal collisions that are more violent than a 23 km/h (14 mph) barrier collision, or similarly, striking a parked car of similar size across the full front of each vehicle at about twice the speed. (The parked car absorbs some of the energy of the crash. )

Unlike crash tests into barriers, real-world crashes typically occur at angles, and the crash forces usually are not evenly distributed across the front of the vehicle. A crash test is a form of Destructive testing usually performed in order to ensure safe design standards in Crashworthiness and Consequently, the relative speed between a striking and struck vehicle required to deploy the airbag in a real-world crash can be much higher than an equivalent barrier crash. Because airbag sensors measure deceleration, vehicle speed and damage are not good indicators of whether an airbag should have deployed. Airbags can deploy due to the vehicle's undercarriage striking a low object protruding above the roadway due to the resulting deceleration.

The airbag sensor is a MEMS accelerometer, which is a small integrated circuit with integrated micro mechanical elements. Microelectromechanical systems ( MEMS) is the technology of the very small and merges at the nano-scale into Nanoelectromechanical systems (NEMS and Nanotechnology An accelerometer is a device for measuring Acceleration and gravity induced reaction forces Microchipsjpg|right|thumb|200px|Microchips ( EPROM memory with a transparent window showing the integrated circuit inside The microscopic mechanical element moves in response to rapid deceleration, and this motion causes a change in capacitance, which is detected by the electronics on the chip that then sends a signal to fire the airbag. The most common MEMS accelerometer in use is the ADXL-50 by Analog Devices, but there are other MEMS manufacturers as well. Analog Devices ( is an American multinational producer of Semiconductor devices

Initial attempts using mercury switches did not work well. A mercury switch (also known as a mercury tilt switch) is a Switch whose purpose is to allow or interrupt the flow of Electric current in an Electrical Before MEMS, the primary system used to deploy airbags was called a "rolamite". Rolamite is a technology for very low Friction bearings developed by Sandia National Laboratories in the 1960s A rolamite is a mechanical device, consisting of a roller suspended within a tensioned band. As a result of the particular geometry and material properties used, the roller is free to translate with little friction or hysteresis. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e A system with hysteresis can be summarised as a system that may be in any number of states independent of the inputs to the system This device was developed at Sandia National Laboratories. Sandia National Laboratories which is managed and operated by the Sandia Corporation (a wholly owned subsidiary of Lockheed Martin Corporation) is a major United The rolamite, and similar macro-mechanical devices were used in airbags until the mid-1990s when they were universally replaced with MEMS. The 1990s collectively refers to the years between and including 1990 and 1999

Nearly all airbags are designed to automatically deploy in the event of a vehicle fire when temperatures reach 150-200 °C (300-400 °F). The Celsius Temperature scale was previously known as the centigrade scale. Fahrenheit is a temperature scale named after Daniel Gabriel Fahrenheit (1686–1736 a German Physicist who proposed it in 1724 This safety feature, often termed auto-ignition, helps to ensure that such temperatures do not cause an explosion of the entire airbag module.

Today, airbag triggering algorithms are becoming much more complex. In Mathematics, Computing, Linguistics and related subjects an algorithm is a sequence of finite instructions often used for Calculation They try to reduce unnecessary deployments (for example, at low speed, no shocks should trigger the airbag, to help reduce damage to the car interior in conditions where the seat belt would be an adequate safety device), and to adapt the deployment speed to the crash conditions. The algorithms are considered valuable intellectual property. Intellectual property ( IP) is a legal field that refers to creations of the mind such as musical literary and artistic works inventions and symbols names Experimental algorithms may take into account such factors as the weight of the occupant, the seat location, seatbelt use, and even attempt to determine if a baby seat is present. See also Baby transport An infant safety seat, a "child restraint system" or "restraint car seat" is a Restraint which is secured

Inflation

When the frontal airbags are to deploy, a signal is sent to the inflater unit within the airbag control unit. A gas generator usually refers to a Propellant mixture often similar to a Solid rocket propellant that burns to produce large volumes of Gas. An igniter starts a rapid chemical reaction generating primarily nitrogen gas (N₂) to fill the airbag making it deploy through the module cover. A chemical reaction is a process that always results in the interconversion of Chemical substances The substance or substances initially involved in a chemical reaction are called Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 Some airbag technologies use compressed nitrogen or argon gas with a pyrotechnic operated valve ("hybrid gas generator"), while other technologies use various energetic propellants. Nitrogen (ˈnaɪtɹəʤɪn is a Chemical element that has the symbol N and Atomic number 7 and Atomic weight 14 This article pertains to the chemical element For other uses see Argon (disambiguation. A propellant is a material that is used to move ("propel" an object Propellants containing sodium azide (NaN₃) were common in early inflater designs. Sodium azide is the Chemical compound with the formula NaN3 This colourless Azide salt is a common reagent in Organic However, propellants containing the highly toxic sodium azide were widely phased out during the 1990s in pursuit of more efficient, less expensive and less toxic alternatives.

The azide-containing pyrotechnic gas generators contain a substantial amount of the propellant. The driver-side airbag would contain a canister which is 5. 0 cm (2") in diameter, 3. A centimetre ( American spelling: centimeter, symbol cm) is a unit of Length in the Metric system, equal to one hundredth Inches redirects here To see the Les Savy Fav album see Inches. 8 cm (1. 5") long, and contains about 50 grams of sodium azide. For other uses of the words gram or gramme see Gram (disambiguation. The passenger side container is 15 cm (6") long and contains 200 grams of sodium azide. ^[14] The incomplete combustion of the charge due to rapid cooling leads to production of carbon monoxide (CO) and nitrogen(II) oxide as reaction byproducts. Carbon monoxide, with the chemical formula CO is a colorless odorless tasteless yet highly toxic Gas. Nitric oxide or nitrogen monoxide is a Chemical compound with Chemical formula N[[Oxygen O]] ^[15]

The alternative propellants may incorporate, for example, a combination of nitroguanidine, phase-stabilized ammonium nitrate (NH₄NO₃) or other nonmetallic oxidizer, and a nitrogen-rich fuel different than azide (eg. Nitroguanidine (NQ(1-Nitroguanidine Picrite CH4N4O2 H2NC(NHNHNO2 is a chemical compound The Chemical compound ammonium nitrate, the Nitrate of Ammonia with the chemical formula N[[Hydrogen H]]4 N[[Oxygen O]]3 tetrazoles, triazoles, and their salts). Tetrazoles are a class of synthetic organic heterocyclic compound, consisting of a 5-member ring of four Nitrogen and one Carbon Triazole (Htrz refers to either one of a pair of Isomeric Chemical compounds with Molecular formula C2H3N3 having a five-membered The burn rate modifiers in the mixture may be an alkaline metal nitrate (NO₃-) or nitrite (NO₂-), dicyanamide or its salts, sodium borohydride (NaBH₄), etc. In Inorganic chemistry, a nitrate is a salt of Nitric acid with an Ion composed of one Nitrogen and three Oxygen atoms The nitrite Ion is NO2− The anion is bent being Isoelectronic with O3. Sodium borohydride, also known as sodium tetrahydroborate, has the Chemical formula Na[[boron B]] H 4 The coolants and slag formers may be eg. Slag is the By-product of Smelting Ore to purify Metals They can be considered to be a mixture of metal Oxides however clay, silica, alumina, glass, etc. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and The Chemical compound silicon dioxide, also known as silica or silox (from the Latin " Silex " is an Oxide ^[16] Other alternatives are eg. nitrocellulose based propellants (which have high gas yield but bad storage stability, and their oxygen balance requires secondary oxidation of the reaction products to avoid buildup of carbon monoxide), or high-oxygen nitrogen-free organic compounds with inorganic oxidizers (e. Nitrocellulose (also cellulose nitrate, flash paper) is a highly flammable compound formed by Nitrating Cellulose through exposure to Oxygen balance ( OB, or OB%) is an expression that is used to indicate the degree to which an explosive can be oxidized g. , di or tricarboxylic acids with chlorates (ClO₃-) or perchlorates (HClO₄) and eventually metallic oxides; the nitrogen-free formulation avoids formation of toxic nitrogen oxides). Carboxylic acids are Organic acids characterized by the presence of a Carboxyl group, which has the formula -C(=OOH usually written -COOH or -CO2H The chlorate anion has the formula ClO3− In this case the Chlorine atom is in the +5 Oxidation state. Perchlorates are the salts derived from Perchloric acid ( H[[chlorine Cl]] O4) The term nitrogen oxide typically refers to any Binary compound of Oxygen and Nitrogen, or to a mixture of such compounds Nitric

From the onset of the crash, the entire deployment and inflation process is about 0. 05 seconds — faster than the blink of an eye (about 0. 2 seconds). Because vehicles change speed so quickly in a crash, airbags must inflate rapidly to reduce the risk of the occupant hitting the vehicle's interior.

Post-deployment

Once an airbag deploys, deflation begins immediately as the gas escapes through vent(s) in the fabric (or, as it's sometimes called, the cushion) and cools. Deployment is frequently accompanied by the release of dust-like particles, and gases in the vehicle's interior (called effluent). Most of this dust consists of cornstarch, french chalk, or talcum powder, which are used to lubricate the airbag during deployment. Cornstarch, or cornflour, is the Starch of the Maize grain commonly known as Corn. French chalk is a type of Talc used by tailors for marking Cloth, by cleaners for removing grease from cloth and as a dry Lubricant in its powdered Baby powder is an Astringent powder used for preventing rashes on the area covered by a Diaper (see Diaper rash) Newer designs produce effluent primarily consisting of harmless talcum powder/cornstarch and nitrogen gas (about 80% of the air we breathe is nitrogen). In older designs using an azide-based propellant (usually NaN₃), varying amounts of sodium hydroxide nearly always are initially present. Sodium hydroxide ( Na[[hydroxide OH]]) also known as Lye, caustic soda and (incorrectly according to IUPAC nomenclature In small amounts this chemical can cause minor irritation to the eyes and/or open wounds; however, with exposure to air, it quickly turns into sodium bicarbonate (baking soda). Sodium bicarbonate or sodium hydrogen carbonate is the Chemical compound with the formula NaHCO3 However, this transformation is not 100% complete, and invariably leaves residual amounts of hydroxide ion from NaOH. Depending on the type of airbag system, potassium chloride (a table salt substitute) may also be present. The Chemical compound potassium chloride (KCl is a Metal Halide salt composed of Potassium and Chlorine.

For most people, the only effect the dust may produce is some minor irritation of the throat and eyes. Generally, minor irritations only occur when the occupant remains in the vehicle for many minutes with the windows closed and no ventilation. However, some people with asthma may develop an asthmatic attack from inhaling the dust. Asthma is a chronic Condition involving the Respiratory system in which the airways occasionally constrict become inflamed, and are With the onset of symptoms, asthmatics should treat themselves as advised by their doctor, then immediately seek medical treatment.

Benefits

Airbags supplement the safety belt by reducing the chance that the occupant's head and upper body will strike some part of the vehicle's interior. A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from They also help reduce the risk of serious injury by distributing crash forces more evenly across the occupant's body. Curtain airbags help to keep all parts of the occupant inside the vehicle.

One recent study concluded that as many as 6,000 lives have been saved as a result of airbags. ^[17]

Costs

Airbags cost about $500 (USD) per vehicle from OEMs, who typically pay the supplier less than $100. An original equipment manufacturer, or OEM is typically a company that uses a component made by a second company in its own product or sells the product of the second company If they are deployed in error or stolen, the registered vehicle owner is required to repurchase them. Since they are an integral part of the vehicle design, it is not usually possible to retrofit airbags to a vehicle that does not have them, though in the early 1990s Breed Technologies of Lakeland, Florida, offered a retro driver side system, the SRS-40 for seven of the top selling vehicles of the time.

The SRS-40 system used the same sensor as the early 1990s Jeep Cherokee. When the vehicle exceeded a preset negative acceleration threshold for a specific length of time, the sensor released two firing pins, initiating the deployment. This simple all-mechanical system eliminated the need for any electrical connections. Sensor calibration was changed from vehicle to vehicle to allow for the structural differences. The kits supplied by Breed included a new steering wheel. A steering wheel (also called a driving wheel or hand wheel) is a type of steering Control in Vehicles and vessels ( Ships and Boats

Most manufacturers specify the replacement of undeployed airbags after a certain period to ensure their reliability in an accident.

Although self installation of used or surplus components may result in considerable cost savings, airbags should only be serviced by those who are properly qualified. Accidental deployment while servicing could result in severe injury, and an improperly installed or defective airbag unit may not provide sufficient protection in an accident. For these reasons, laws limiting sale, shipping, handling and maintenance have been imposed in several countries. In Germany, where some of the strictest laws are in place, airbags count as harmful explosives, and only car mechanics with additional special training are allowed to service airbag systems. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. An auto mechanic (or car mechanic in British English and motor mechanic in Australian English) is a Mechanic who specializes in Under German Federal Law, used but intact airbags are to be detonated under secure conditions, and must not be passed on to third parties in any way, and private (i. The Basic Law for the Federal Republic of Germany (Grundgesetz für die Bundesrepublik Deutschland is the Constitution of Germany. e. layman) individuals are not allowed to handle airbags under any circumstances. Legal purchase is restricted to buying a new replacement unit for immediate installation by the seller's qualified personnel.

Airbag injuries and fatalities

Airbags involve the extremely rapid deployment of an object with explosives. While airbags can protect a person under the right circumstances, they can also injure or kill. To protect occupants not wearing seat belts, U. A seat belt, sometimes called a safety belt, is a Safety harness designed to secure the occupant of a Vehicle against harmful movement that may result from S. airbag designs trigger much more quickly than airbags designed in other countries. As seat belt use in the U. S. climbed in the late 1980s and early 1990s, auto manufactures were able to adjust their designs. Today, all airbag control units recognize if a belt is used, and set the trigger time accordingly. ^[18]

Newer airbag designs trigger at a lesser speed; nonetheless, occupants are strongly advised to remain at least 25 centimeters (10 in) from the panel from which frontal airbags deploy, to avoid injury from the bag in a crash. While driving, a driver must be seated so that the center of the chest remains 25 centimeters (10 in) from the center of the steering wheel hub. The design of side airbags means occupants of a vehicle must not lean against the inside of the car window or doors, the pillars or place objects between themselves and the side of the vehicle. Despite many cars still featuring hooks on passenger assist grips, these can not be used when side thorax, and in particular, curtain airbags are fitted. ^[19]

Minor and/or superficial injuries, such as abrasion of the skin, hearing damage (from the sound during deployment), head injuries, eye damage for spectacle wearers and breaking the nose, fingers, hands or arms can occur as the airbag deploys. Most vehicle airbags are inflated using hot gas generated by a chemical process. Using hot gas allows the required pressure to be obtained with a smaller mass of gas than would be the case using lower temperatures. However, the hot gas can pose a risk of thermal burns if it comes in contact with the skin during deployment and occupant interaction. Burns are most common to the arms, face and chest. These burns are often deep dermal or second-degree burns that take longer to heal and risk scarring.

In 1990, the first automotive fatality attributed to an airbag was reported, with deaths peaking in 1997 at 53 in the United States. TRW produced the first gas-inflated airbag in 1994, with sensors and low-inflation-force bags becoming common soon afterwards. TRW Incorporated was an American Corporation involved in a number of businesses mostly defense-related but including Automotive, Aerospace and Dual-depth (also known as dual-stage) airbags appeared on passenger cars in 2005. By that time, deaths related to airbags had declined, with no adult deaths and two child deaths attributed to airbags that year. Injuries remain fairly common in accidents with an airbag deployment.

Airbags must inflate very rapidly to be effective, and therefore come out of the steering wheel hub or instrument panel with considerable force, generally at a speed of about 97. 8 m/s (220 mph). Because of this initial force, contact with a deploying airbag may cause injury. These airbag contact injuries, when they occur, are typically very minor abrasions or burns. The sound of airbag deployment is very loud, in the range of 165-175 dB for 0. The decibel ( dB) is a logarithmic unit of measurement that expresses the magnitude of a physical quantity (usually power or intensity relative to 1 second. Hearing damage can result in some cases.

More serious injuries are rare; however, serious or even fatal injuries can occur when someone is very close to, or in direct contact with an airbag when the airbag deploys. Such injuries may be sustained by unconscious drivers who are slumped over the steering wheel, unrestrained or improperly restrained occupants who slide forward in the seat during pre-crash braking, and even properly restrained drivers who sit very close to the steering wheel. Objects must never be attached to an airbag, or placed loose on or near an airbag, since they can be propelled with great force by a deploying airbag, potentially causing serious injuries.

The increasing use of airbags may actually make rescue work for firefighters, emergency medical service and police officers more dangerous. Firefighters are rescuers extensively trained primarily to put out hazardous Fires that threaten civilian populations and property to rescue people from car accidents collapsed Emergency medical services (abbreviated to the initialism "EMS" in many countries are a branch of Emergency services dedicated to providing out-of-hospital Police are agents or agencies usually of the executive, empowered to enforce the law and to effect public and social order through the legitimatized use of force Every first responder should be properly trained on how to safely deactivate airbags or be aware of the potential hazards. Removing the car battery does not deactivate the airbags.

Improvements in sensing and gas generator technology have allowed the development of second generation airbag systems that can adjust their deployment parameters to size, weight, position and restraint status of the occupant. These improvements have demonstrated a reduced injury risk factor for small adults and children who had an increased risk of injury with first generation airbag systems. ^[20]

Safe use of airbags

An unrestrained or improperly restrained occupant can be seriously injured or killed by a deploying airbag. The National Highway Traffic Safety Administration (NHTSA) recommends drivers sit with at least 25 cm (10") between the center of their breastbone and the center of the steering wheel. The National Highway Traffic Safety Administration ( NHTSA, often pronounced "nit-suh" is an agency of the Executive Branch of the U The sternum (from Greek στέρνον sternon, "chest" or breastbone) is a long flat Bone located in the center of the thorax (chest Children under the age of 13 years should always be properly restrained in a rear seat^[21]. A rear-facing infant restraint must never be put in the front seat of a vehicle with a front passenger airbag. A rear-facing infant restraint places an infant's head close to the airbag, which can cause severe head injuries, or death if the airbag deploys. Traumatic brain injury. THIS PAGE IS FOR INFORMATION ON HEAD INJURY (NOT SPECIFICALLY THE BRAIN--> Head injury is Some modern cars include a switch to disable the front passenger airbag, (although not in Australia, where rear-facing child seats must not be used in the front where an airbag is fitted), in case a child-supporting seat is used there.

Smoking a pipe should be avoided while driving. A pipe is a tool used for Smoking. The designs of pipes vary considerably but for the most part they are reusable and consist of a chamber or bowl in which the substance to If the airbag inflates and hits the pipe, it is likely to be fatal, even if the crash is moderate.

Aerospace and military applications

NASA engineers test the Mars Pathfinder airbag landing system on simulated Martian terrain

The aerospace industry and the US Government has applied airbag technologies for many years. The Mars Pathfinder was launched on December 4, 1996 by NASA aboard a Delta II just a month after the Mars Global Surveyor Landing is the last part of a Flight, where a flying Animal, Aircraft, or Spacecraft returns to the ground This article is about the field of research and industry for the corporation see The Aerospace Corporation Aerospace comprises the The federal government of the United States is the central United States Governmental body established by the United States Constitution. NASA, and US DoD have incorporated airbag systems in various aircraft and spacecraft applications as early as the 1960s. The National Aeronautics and Space Administration ( NASA, ˈnæsə is an agency of the United States government, responsible for the nation's public space program The United States Department of Defense ( DOD or DoD) is the federal department charged with coordinating and supervising all agencies and functions of the government

OH-58D CABS test

Airbag landing systems

The first use of airbags for landing were Luna 9 and Luna 13, which landed on the Moon in 1966 and returned panoramic images. Landing is the last part of a Flight, where a flying Animal, Aircraft, or Spacecraft returns to the ground Sources The Mars Pathfinder lander employed an innovative airbag landing system, supplemented with aerobraking, parachute, and solid rocket landing thrusters. The Mars Pathfinder was launched on December 4, 1996 by NASA aboard a Delta II just a month after the Mars Global Surveyor Aerobraking is a Spaceflight maneuver that reduces the high point of an Elliptical orbit ( Apoapsis) by flying the vehicle through the Atmosphere A parachute is a device used to slow the motion of an object through an atmosphere by creating drag. A solid rocket or a solid-fuel rocket is a Rocket with a motor that uses solid propellants ( Fuel / Oxidizer) This prototype successfully tested the concept, and the two Mars Exploration Rover Mission landers employed similar landing systems. NASA 's Mars Exploration Rover ( MER) Mission is an ongoing robotic mission of exploring Mars, that began in 2003 with the sending of The Beagle 2 Mars lander also tried to use airbags for landing, but the landing was unsuccessful for reasons which are not entirely known. Beagle 2 was an unsuccessful British landing spacecraft that formed part of the European Space Agency 's 2003 Mars Express mission

Occupant protection

The US Army has incorporated airbags in its UH-60A/L^[22] Black Hawk and OH-58D Kiowa Warrior^[23] helicopter fleets. The United States Army is a military organization whose primary mission is to "provide necessary forces and capabilities. WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout WikipediaWikiProject Aircraft. Please see WikipediaWikiProject Aircraft/page content for recommended layout The Cockpit Air Bag System (CABS) consists of forward and lateral airbags with an Electronic Crash Sensor Unit (ECSU). ^[24] The CABS system was conceived and developed by the US Army Aviation Applied Technology Directorate, Fort Eustis, Va. The US Army Aviation Applied Technology Directorate (AATD is a tenant activity located at Fort Eustis, Virginia. Fort Eustis is a United States Army military installation located in Newport News Virginia. The Commonwealth of Virginia ( is an American state ^[25] It is the first conventional airbag system for occupant injury prevention designed and developed specifically for helicopter applications. ^[26][27]

See also

• Assen Jordanoff
• Automobile safety
• Safety standards

References

External links

• Airbag Information and Airbag Deployment video in slow motion
• Howstuffworks : "How Airbags Work"
• Chemistry behind airbags
• Internals of airbag module (enclosure removed)