The truck market is constantly evolving, and with it, so are braking devices. If you are studying to obtain the C driving license, i.e., the license that qualifies individuals to drive goods transport vehicles (a CQC license is required for the professional transport of goods), you will undoubtedly have come across, within the preparation quizzes on the Highway Code, a question on the air braking system of heavy vehicles. Let’s find out together what this is all about!
Heavy duty truck braking system
Before we begin and analyze the air brake system, it is good to make a premise about the heavy-duty truck brake system.
First, the brake system can be of various types and varies according to the size of the vehicle. The hydraulic system, pneumatic system, pneumohydraulic system and finally the mechanical system are mainly distinguished.
In the hydraulic system for small vehicles, the braking force is transmitted through oil. In contrast, in the pneumatic system, the braking force is transmitted by compressed air. As for the air-hydraulic system, it is a half system in which air braking force is transmitted by compressed air. Finally, the mechanical system is structured for parking brakes, such as the spring brake.
We come to the air brake system of heavy vehicles. Vehicles with a mass of more than 3.5 tons not intended for passenger transport (such as trucks, tractor-trailers, and articulated vehicles) use an air brake system. As we have seen, in summary, compressed air is used to stop or slow down.
Technically, using words related to mechanics, the means of decongesting the energy collected during vehicle movement come from the release of air that transforms it into heat energy causing it to slow down or stop.
This system, at one time, was prone to air leaks that could cause the vehicle to malfunction, and you often ended up with a vehicle that was not equipped with proper brakes.
With advances in the field of mechanics, especially in recent times, a system has been introduced that reinserts air in the event of air leaks so that we always have a brake system that knows how to perform at its best.
Understanding the workings of the air brake system and the brake system in general can really help not only to pass a test as tough as the one for the C license, but first and foremost to keep the driver safe.