What is the purpose of the air tank in an air brake system?

The air tank's primary function in an air brake system is to store compressed air for braking. This storage is crucial because it allows for the accumulation of sufficient air pressure needed to operate the brake system effectively. When the brake pedal is pressed, this stored compressed air is released and directed to apply the brakes, thus facilitating a reliable and responsive braking action.

The air tank's ability to maintain a reserve of air ensures that the braking system can function over multiple applications without depleting its pressure, allowing for consistent and safe operation of the vehicle. Without this stored compressed air, the brakes would not engage properly, significantly compromising vehicle safety.

Other functions mentioned, like cooling the brake system, maintaining hydraulic pressure, or filtering air, are not the main purposes of the air tank. Instead, those responsibilities are handled by other components within the braking system.