What is the working principle of an air brake system?
4 Answers
The working principle of an air brake system involves an air compressor driven by the engine, which compresses air and delivers it through a one-way valve into a wet reservoir. Inside the wet reservoir, the compressed air is cooled and undergoes oil-water separation. The air is then divided into two circuits: one circuit passes through the air reservoir and the middle chamber of a dual-chamber brake valve to reach the rear brake chamber, while the other circuit passes through the air reservoir and the lower chamber of the dual-chamber brake valve to reach the front brake chamber. Below is a detailed explanation: 1. When not braking. Both solenoid valves are not energized; the intake solenoid valve remains normally closed, and the exhaust solenoid valve remains normally open. Both diaphragm valves are closed under the action of their springs, ready to engage in braking at any time. 2. When braking. Neither solenoid valve is energized. Compressed air from the brake valve enters the right side of the diaphragm-type intake valve. Since the intake solenoid valve is closed, the passage between the compressed air and the control chamber on the left side of the intake diaphragm is cut off. At this time, the control chamber is vented to the atmosphere, and under the pressure difference, the diaphragm-type intake valve opens, allowing compressed air to enter the pipeline leading to the brake chamber. Additionally, since the exhaust solenoid valve is also not energized and remains open, compressed air enters the control chamber on the right side of the diaphragm-type exhaust valve. Under the combined action of its spring force and air pressure, the diaphragm-type exhaust valve remains reliably closed, ensuring that compressed air flows unimpeded into the brake chamber, producing a follow-up braking effect.
The working principle of the air brake system relies heavily on compressed air. I've been driving heavy-duty trucks for over a decade, and this thing is my old companion. The engine drives an air compressor, which compresses air and stores it in an air reservoir. When you press the brake pedal, a valve opens, allowing compressed air to quickly flow into the brake chamber, pushing the piston to press against the brake drum and generate massive friction to slow down the vehicle. The key is to ensure sufficient air pressure, so I often remind my peers to regularly check the air reservoir and pipelines for leaks, and to test the brakes multiple times before climbing hills to ensure quick system response. Under heavy loads, air brakes are more reliable than hydraulic brakes, but don't forget to clean the air filter to prevent compressor damage and avoid accidents.
When working in the workshop, I encounter issues with the air brake system every day. It operates by having the air compressor first pump air into the storage tank. When the driver steps on the brake, the pedal controls the valve to release air, which impacts the braking device to execute the braking. The advantage is its powerful force and high-temperature resistance, especially in large buses. I've seen many faults, such as aging pipelines leaking air, resulting in insufficient pressure and the vehicle failing to brake properly, or winter freezing blocking the airflow. Therefore, we mechanics recommend servicing the system every six months, checking the pressure to ensure it's normal, and replacing parts to extend its lifespan.
Pneumatic braking systems use air pressure to stop the vehicle: Compressed air is stored in tanks, and when the brake pedal is pressed, the air is released to actuate components that halt the vehicle. Trucks commonly use this system because it provides sufficient stopping power and is relatively simple to maintain. However, remember to regularly check the air supply to prevent interruptions, as a failure could weaken braking performance.
