What are SRS Airbags: Features, Types & Working

If you carefully notice your steering and dashboard region, you will find alphabetic symbols like TPMS, ABS, SRS, and ESC. These are certain indicators and have specific functions.

In this piece, we will be discussing SRS, which stands for Supplemental Restraint System. Every vehicle comes with built-in safety equipment to protect the occupants at the time of serious accidents. SRS is an airbag system that works with three-point seatbelts.

Want to know more about “SRS airbags”? Continue reading!

The purpose of implementing SRS airbags is to protect the driver and the passengers in a car. This system functions by controlling the automatic airbags, restraints, and seatbelts in case of any collision.

This restraint system is designed in such a way that it detects deceleration, braking, impact location, and the presence of a passenger. Based on the information gathered, it decides which airbags to inflate and whose seat belts need to be tightened.

These airbags inflate only when the sensors mentioned above will detect an impact and comprehend the intensity of the collision. In such scenarios, these airbags take approximately 0.03 seconds to get inflated. In some cars, side-impact airbags are also present to protect the passenger's head and upper body during any sideways accident.

SRS is composed of a gas-generator module that gets triggered when the amount of force is huge. This is when the gas inside this system explodes and inflates those airbags.

Other than airbags, SRS or Supplemental Restraint System also contains the following features:

• Warning light
• Passenger seat switches
• Pyrotechnic inflator
• Igniter
• Crash Sensors
• Electronic Control Unit

Here's a list of different types of SRS airbags that are used in a car.

• Driver Airbags
• Passenger Airbags
• Side-Curtain Airbags
• Knee Bolster Airbags
• Seat Mounted Airbags
• Pedestrian Airbags
• Inflatable Seatbelt Airbags
• Rear Mirror Airbags
• Seat Cushion Airbags
• Rear Seat Centre Airbags

To know how this works, you must be aware of all kinds of sensors that connect with this system. This includes:

• Speed Sensor
• Acceleration Sensor
• Brake Pressure Sensor
• Door Pressure Sensor
• Gyroscope Sensor and
• Seat Occupation Sensor

With all these sensors mentioned in the above heading, the airbag module also connects to an electronic control unit. Each airbag has a different set of modules, which contains three chemicals, Sodium Azide, Potassium Nitrate, and Silicon Dioxide.

Therefore, when a car crashes, all the sensors send a signal to the electronic control unit. At this moment, the ECU calculates and decides which airbag needs to get inflated at first. Then the process happens in three stages:

• Immediately after receiving a signal, the temperature increases (above 300° Celsius), which then creates an impact on Sodium Azide to produce nitrogen gas.
• Potassium Nitrate reacts with Sodium Azide and increases the flow of nitrogen gas. This results in the airbags’ inflation, which prevents injuries.
• This nitrogen gas is then released into the atmosphere, so there is no suffocation.

Almost everyone gets confused with this terminology. SRS is the system that deploys airbags during any crash. There is no difference between them.

Airbags are symbolised with SRS, which is visible either on the dashboard or on the steering wheels. This symbol is responsible for indicating if there is an issue with the system. Therefore, if you notice this symbol flash, you must check by yourself what is the problem or take it to a garage.

The light flashes in a specific way to help understand where an issue is exactly located. For example, if it flashes twice, pauses, and then flashes again, this implies code 21 needs to be taken care of.