It all started in 1971, with a little old company you might know today as Ford. Ford started putting airbags in cars that were only sold to the government initially. In 1973, General motors were building an experimental airbag on the 1973 model of Chevrolet, General Motors tested airbags which were only sold for government use. The Oldsmobile Toronto was the first car that had a passenger airbag and was later on sale for the public in 1973.
In 1975 and 1976, General Motors offered an option to the general public of driver side airbags in full-sized Oldsmobile’s and Buick’s. During the same time periods, Cadillacs were available with driver and passenger airbags options. Early airbags had issues in design resulting in fatalities caused solely by the airbags.
In 1984, Ford Tempo automobile offered airbags once again as an option. The first company to offer airbag restraint systems as standard equipment was Chrysler around 1988. The Thompson Ramo Wooldridge Company (TRW), involved mainly in automotive and aerospace electronic engineering, began the production of the first gas-inflated airbag in 1994. Since 1998, they were made mandatory in all cars.
Types of Airbags The two types of airbags are frontal and the various types of side-impact airbags. Advanced frontal air bag systems automatically determine what level of power the passenger and driver frontal airbags will inflate to. The appropriate level of power is based upon four sensor inputs that can typically detect occupant size, seat position, seat belt use, and crash severity. Side-Impact airbags (SABs) are designed to help protect your head and/or chest in the event of a serious crash involving the side of your vehicle. The three main types of SABs are: chest(or torso) SABs, head SABs, and head/chest combination (or combo) SABs.
How Airbags Work An airbag's goal is to slow the passenger’s forward motion as evenly as possible in a fraction of a second. There are parts of the airbag that would help accomplish this. The first is the bag itself, the bag can be folded into the steering wheel, dashboard, seat, or door. The second part is the sensor, the sensor tells the bag when to inflate. The last part is the airbag’s inflation system, the airbag’s inflation system produces nitrogen gas by utilizing the reaction of sodium azide with potassium nitrate.
Chemical Reactions Used to Generate the Gas
There is a gas generator inside the airbag, which contains a mixture of KNO3, SiO2 and NaN3. When the car undergoes collision, a total of three chemical
reactions takes place inside the gas generator which produces nitrogen gas that fills the AIRBAG and converts NaN3, which is a harmless glass and also highly toxic. Sodium azide can decompose at 300oC to produce sodium metal (Na) and nitrogen gas (N2). There will be a signal from the deceleration sensor which ignites the generator gas, which is mixed by an electrical impulse. This creates the high-temperature condition necessary for NaN3 to decompose. The nitrogen gas that is generated then fills the airbag. The purpose of the KNO3 and SiO2 is to remove the sodium metal which is highly reactive and potentially explosive, as you recall from the Periodic Properties Experiment, which will convert it to a harmless material. First, the sodium reacts with potassium nitrate (KNO3) to produce potassium oxide (K2O), sodium oxide (Na2O), and additional N2 gas. The N2 generated in this second reaction also fills the airbag, and the metal oxides react with silicon dioxide (SiO2) in a final reaction to produce silicate glass, which is harmless and stable. (First-period metal oxides, such as Na2O and K2O, are highly reactive, so it would be unsafe to allow them to be the end product of the airbag detonation.)
Airbag and inflation system
Early efforts to adapt the airbag for use in cars bumped up against prices and technical hurdles that were prohibited which involved the storage and release of compressed gas. There were many things that researchers wondered, such as: whether or not a gas cylinder could fit in the car; whether or not the gas would remain in the life of the car at a high pressure; and whether or not the bag could expand quickly and reliably at a variety of operating temperatures and if it could do it without emitting an ear-splitting bang.
Solid Propellant and Igniter
They had to find a way to set off a chemical reaction that would produce the nitrogen and inflate the bag. In the 1970s, small solid-propellant inflators came to the rescue. The inflation system is not like a solid rocket booster. A solid propellant (which gets ignited by the airbag) burns rapidly to create a large volume of gas to inflate the bag. This reaction is similar to a gun shot without the bullet. The bag bursts up to 200 mph (322 kph) from its storage site. The gas quickly dissipates through tiny holes in the bag a second later. Then it deflates the bag so you can move. Even though the whole process happens in about 1/25 of a second, the additional time is enough to prevent serious injuries. Most people do not realize that an airbag is violent and will hurt when impacted; however, this prevents more serious injuries. The powdery substance released from the airbag is regular cornstarch or talcum powder, which is used by the airbag manufacturers to keep the bags lubricated while they are in storage.
ESTIMATED NUMBER OF LIVES SAVED EACH YEAR BY AIRBAGS:
History
It all started in 1971, with a little old company you might know today as Ford. Ford started putting airbags in cars that were only sold to the government initially. In 1973, General motors were building an experimental airbag on the 1973 model of Chevrolet, General Motors tested airbags which were only sold for government use. The Oldsmobile Toronto was the first car that had a passenger airbag and was later on sale for the public in 1973.
In 1975 and 1976, General Motors offered an option to the general public of driver side airbags in full-sized Oldsmobile’s and Buick’s. During the same time periods, Cadillacs were available with driver and passenger airbags options. Early airbags had issues in design resulting in fatalities caused solely by the airbags.
In 1984, Ford Tempo automobile offered airbags once again as an option. The first company to offer airbag restraint systems as standard equipment was Chrysler around 1988. The Thompson Ramo Wooldridge Company (TRW), involved mainly in automotive and aerospace electronic engineering, began the production of the first gas-inflated airbag in 1994. Since 1998, they were made mandatory in all cars.
Types of Airbags
The two types of airbags are frontal and the various types of side-impact airbags. Advanced frontal air bag systems automatically determine what level of power the passenger and driver frontal airbags will inflate to. The appropriate level of power is based upon four sensor inputs that can typically detect occupant size, seat position, seat belt use, and crash severity.
Side-Impact airbags (SABs) are designed to help protect your head and/or chest in the event of a serious crash involving the side of your vehicle. The three main types of SABs are: chest(or torso) SABs, head SABs, and head/chest combination (or combo) SABs.
How Airbags Work
An airbag's goal is to slow the passenger’s forward motion as evenly as possible in a fraction of a second. There are parts of the airbag that would help accomplish this. The first is the bag itself, the bag can be folded into the steering wheel, dashboard, seat, or door. The second part is the sensor, the sensor tells the bag when to inflate. The last part is the airbag’s inflation system, the airbag’s inflation system produces nitrogen gas by utilizing the reaction of sodium azide with potassium nitrate.
Chemical Reactions Used to Generate the Gas
There is a gas generator inside the airbag, which contains a mixture of KNO3, SiO2 and NaN3. When the car undergoes collision, a total of three chemical
reactions takes place inside the gas generator which produces nitrogen gas that fills the AIRBAG and converts NaN3, which is a harmless glass and also highly toxic. Sodium azide can decompose at 300oC to produce sodium metal (Na) and nitrogen gas (N2). There will be a signal from the deceleration sensor which ignites the generator gas, which is mixed by an electrical impulse. This creates the high-temperature condition necessary for NaN3 to decompose. The nitrogen gas that is generated then fills the airbag. The purpose of the KNO3 and SiO2 is to remove the sodium metal which is highly reactive and potentially explosive, as you recall from the Periodic Properties Experiment, which will convert it to a harmless material. First, the sodium reacts with potassium nitrate (KNO3) to produce potassium oxide (K2O), sodium oxide (Na2O), and additional N2 gas. The N2 generated in this second reaction also fills the airbag, and the metal oxides react with silicon dioxide (SiO2) in a final reaction to produce silicate glass, which is harmless and stable. (First-period metal oxides, such as Na2O and K2O, are highly reactive, so it would be unsafe to allow them to be the end product of the airbag detonation.)
Airbag and inflation system
Early efforts to adapt the airbag for use in cars bumped up against prices and technical hurdles that were prohibited which involved the storage and release of compressed gas. There were many things that researchers wondered, such as: whether or not a gas cylinder could fit in the car; whether or not the gas would remain in the life of the car at a high pressure; and whether or not the bag could expand quickly and reliably at a variety of operating temperatures and if it could do it without emitting an ear-splitting bang.
Solid Propellant and Igniter
They had to find a way to set off a chemical reaction that would produce the nitrogen and inflate the bag. In the 1970s, small solid-propellant inflators came to the rescue. The inflation system is not like a solid rocket booster. A solid propellant (which gets ignited by the airbag) burns rapidly to create a large volume of gas to inflate the bag. This reaction is similar to a gun shot without the bullet. The bag bursts up to 200 mph (322 kph) from its storage site. The gas quickly dissipates through tiny holes in the bag a second later. Then it deflates the bag so you can move. Even though the whole process happens in about 1/25 of a second, the additional time is enough to prevent serious injuries. Most people do not realize that an airbag is violent and will hurt when impacted; however, this prevents more serious injuries. The powdery substance released from the airbag is regular cornstarch or talcum powder, which is used by the airbag manufacturers to keep the bags lubricated while they are in storage.
ESTIMATED NUMBER OF LIVES SAVED EACH YEAR BY AIRBAGS:
References:
How do airbags work? (2017, September 10). Retrieved October 06, 2017, from http://www.explainthatstuff.com/airbags.html
Brain, M. (2000, April 01). How Airbags Work. Retrieved October 09, 2017, from
http://auto.howstuffworks.com/car-driving-safety/safety-regulatory-devices/airbag1.htm
Chemistry.wustl.edu. (2017). Gas Laws Save Lives:. [online] Available at: http://www.chemistry.wustl.edu/~edudev/LabTutorials/CourseTutorials/Tutorials/Airbags/gas_06.htm [Accessed 4 Nov. 2017].
(n.d.). Retrieved November 04, 2017, from http://www.chemistry.wustl.edu/~edudev/LabTutorials/CourseTutorials/Tutorials/Airbags/gas_06.htm