What is the primary function of a relay valve in an air brake system?

The primary function of a relay valve in an air brake system is to improve the response time of the brakes. This component acts as an intermediary between the brake pedal and the brake chambers on the wheels. When the driver presses the brake pedal, a signal is sent to the relay valve, which quickly and efficiently supplies air to the brake chambers. This rapid air delivery reduces the time it takes for the brakes to engage, enhancing overall braking performance and safety.

By improving response time, the relay valve enables the braking system to activate more promptly, which is especially critical in situations where quick stopping is necessary. This function contributes significantly to the effectiveness of an air brake system, particularly in larger vehicles that require substantial power and coordination to halt safely.