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

The purpose of the air dryer in an air brake system is to remove moisture and contaminants from the air supply. When compressed air is generated, it often carries moisture and dirt particles that can be detrimental to the functionality and longevity of the brake system components. By incorporating an air dryer, the system ensures that the air supplied to the brake system is clean and dry, which helps prevent freezing in cold temperatures and reduces wear on mechanical parts. This is particularly important because moisture can lead to corrosion and system malfunctions, thereby compromising safety and performance.

The other aspects mentioned, like cooling the air compressor or increasing brake pressure, are not the primary functions of the air dryer. Noise reduction is also not relevant to the air dryer's role in the system. The air dryer's main job is focused on maintaining the quality of the compressed air for optimal operation of the air brake system.