What is the working principle of a brake relay valve?
2 Answers
Working principle of the brake relay valve: When the brake pedal is pressed, the output air pressure from the brake valve serves as the control pressure input for the relay valve. Under the control pressure, the intake valve is pushed open, allowing compressed air to flow directly from the air reservoir into the brake chamber through the intake port, bypassing the brake valve. This significantly shortens the air filling path for the brake chamber and accelerates the air filling process. Below is an introduction to the brake relay valve: 1. Function: The relay valve is part of the vehicle's air brake system. In the braking system of heavy-duty vehicles, the relay valve serves to reduce reaction time and pressure buildup time. 2. Differential relay valve: It prevents simultaneous operation of the driving and parking systems, overlapping forces in the combined spring brake cylinder and spring brake chamber, thereby avoiding overloading of mechanical transmission components and ensuring rapid filling and exhausting of the spring brake cylinder.
I have repaired many automotive brake systems, and the working principle of the brake relay valve is primarily to amplify the air pressure signal. When the driver steps on the brake, air pressure is transmitted from the air reservoir into the relay valve. Inside this valve, there are piston and spring mechanisms that, driven by the air pressure, amplify the original signal and then deliver it to the wheel cylinders. This functions like a booster for the braking system, especially in large vehicles such as trucks or buses, providing stronger and more stable braking force. The internal design emphasizes air pressure control to ensure rapid transmission of pedal action and prevent braking delays. During routine maintenance, it's important to keep the air reservoir clean to avoid clogging from dirt. If the valve fails, the entire braking system may malfunction, compromising driving safety.
