Safety Airbags in Cars

Use of safety airbags

1. TECHNICAL SEMINAR ON “ SAFETY AIRBAGS IN CARS ” ABINASH PARICHHA MECHANICAL ENGINEERING REGD NO. 1401109383

2. OVERVIEW OF THE TOPIC Introduction The basics of Airbags Development of Airbags Main parts of Airbags Sensor types Working of Airbags Future of Airbags Conclusion

3. INTRODUCTION 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, 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. Air bags have been under development for many years.

4. No safety device has consumed more attention and resources than the airbag. It is known with high confidence that when a crash occurs the presence of airbag reduces fatality risk to drivers. Airbags are subject of serious government and industry research .

5. THE BASICS OF AIR BAGS Newton’ second Law of motion: If objects aren’t applied any force ,they will continue moving at the speed of the moving car even if the car is stopped by collision. All airbag need to do is to slow down passenger’s speed.

6. MAIN PARTS OF AIRBAG BAG SENSOR INFLATION SYSTEM

7. BAG Made of a thin, nylon fabric, which is folded into the steering wheel or dashboard or, the seat or door. The powdery substance released(regular cornstarch or talcum powder) is used to keep the bags lubricated while they’re in storage.

8. SENSORS The sensor is the device that tells the bag to inflate. It has the control module to discriminate between crash and non-crash events. work on the principle of detecting a decrease in acceleration of a moving vehicle and generate an electrical impulse TYPES Mass Type Sensor Roller Type Sensor

9. Mass Type Sensor(Impact sensor) Fitted to the front of the vehicle. This safety sensor is required to measure the intensity of the collision to determine whether the impact is over a certain threshold to justify release of an airbag. Structural components to an Inertia sensor. Source: Duffy, J.E. (2001). I­Car Professional Automotive Collision . Repair. New York: Delmar, a division of Thomas Learning

10. During a collision the sensing mass is forced forward into the gold plated contacts as a result of change in the state of motion. Roller Type Sensor I t involves a weight connected to a coil spring component. The metal weight is forced forward which alters the tension on the coil spring to manipulate the electrical circuit that closes off the sensor contact. Functional principle to a typical roller type airbag sensor. Source : Erjavec, J. (2010). Automotive Technology: A Systems Approach. New York: Delmar, Cengage Learning .

11. INFLATION SYSTEM Consists of a gas generator containing a mixture of NaN3,KNO3 and SiO2. REACTIONS 2NaN3 ---- 2Na+3N2 10Na+2KNO3 --- K2O+5Na2O+N2 K2O+Na2O+SiO2 -- Na2K2SiO4(alkaline silicate glass) Hot Blasts of the nitrogen inflate the air bag from its storage site up to 332 Kmph.

12. INFLATOR ASSEMBLY Control module activates the airbag assembly. an electric current is sent to the detonator , which ignites the sodium azide pellets. Center for applied technology-http:// www.cast.org

13. WORKING OF AIR BAGS The deployment accompany activation of array of sensors. Air Bags are designed to inflate in frontal impacts in which the car strikes about 16 kilometres per hour. ACU decides if and how to deploy the air bags. After collision, sensors sends an electric current to igniter system. The electric currents heat a filament (wire),which ignites a capsule which in turn ignites the gas generating pellets. The gas expands quickly and inflation of airbags thereby takes place, which breaks through a plastic cover in the steering wheel. The whole process takes about 0.04 second.

14. http://www.opelegypt.net/vehicles/opel-range/cars/mokka/features/safety-driver-assistance.html

15. FUTURE OF AIR BAGS SMART SYSTEMS Weight sensors Determine what type of occupant is in the seat,i.e adult or child. Infrared occupant detection To detect the distance the passenger is from the airbag. Capacitive Reflective Occupant sensing Identify the distance passenger from dashboard. To discriminate between a human occupant and inanimate objects.

16. Updated sensors Deploy the seat belt pretensioners faster to get benefits of the airbags. Centralized electronic control unit The new sensor technology through new software.

17. CONCLUSIONS Air bags are of greater importance in today’s vehicles since safety of human life is of prior importance. So far safe riding and for saving the precious life the safety bags must be implemented. Let’s hope every automobile manufacturer implement the same.

18. REFERENCE Leonard Evans, “Airbag benefits, airbag costs”, journal of Science Servicing Society,2003 www.howstuff works.com www.scienceservicinsociety.com V.E.WEZEL - Airbags Systems - Actual Status and Outlook for the Future Safety The Vehicle and The Road Vol.2, FISITA 92 FISITA No. 925217, page no . 1 Experience'. Frontal impact protection seat belts and airbags, 1993,SAE - SP - 947