The process of the trailer control valve providing compressed air to the trailer's brake system can be described in detail as follows:
When the main vehicle brakes: When the main vehicle driver presses the brake pedal, the trailer brake control valve will respond immediately and send a brake air pressure signal to the trailer control valve through the brake line. When the brake air pressure signal from the main vehicle is received, this air pressure acts on the specific control port of the piston, pushing the piston downward. As the piston descends, a series of valves will act in a preset sequence. First, the exhaust port will be closed to prevent the gas in the trailer brake air chamber from escaping. Next, the intake valve will be pushed open to allow the compressed air in the trailer cylinder to enter the trailer brake air chamber. As the intake valve opens, the compressed air in the trailer cylinder will quickly enter the trailer brake air chamber through the open intake valve and outlet. This inflation process will quickly increase the air pressure in the brake air chamber, thereby generating enough braking force to slow down or stop the trailer.
Synchronization and regulation of air pressure: To ensure that the trailer brakes synchronously with the main vehicle, the trailer control valve constantly monitors the air pressure in the pipeline. This air pressure will continue to act on the lower surface of the piston to ensure that the trailer produces brakes with the same intensity as the main vehicle. If the air pressure at the trailer air cylinder interface is lower than the air pressure at the charging interface (i.e., the air pressure in the trailer brake air chamber is insufficient), the main vehicle will continue to charge the trailer air cylinder through the trailer control valve. This process ensures that the trailer brake air pressure is stable and sufficient, thereby providing a reliable braking effect.
When the main vehicle brakes are released: When the main vehicle brakes are released, the trailer brake control valve will immediately change its output signal. This control signal will be transmitted to the trailer control valve through the brake line, indicating the release of the trailer brake system. After receiving the release signal, the piston of the trailer control valve will begin to move upward. This movement is driven by the gas in the trailer air chamber line. As the piston rises, the exhaust port will be opened to allow the gas in the trailer brake air chamber to be discharged. As the gas is discharged, the air pressure in the trailer brake air chamber will drop rapidly. This causes the trailer brakes to release, allowing the trailer to reaccelerate or maintain its current speed.
Handling in abnormal situations: During driving, if the inflation pipeline suddenly ruptures or leaks, the pressure at the trailer cylinder interface will drop rapidly. The trailer control valve has the ability to detect this pressure change. When a pressure drop is detected, the trailer control valve immediately enters automatic braking mode. In this mode, the piston moves upward, closing the exhaust port and opening the intake valve. The trailer will automatically brake even if the host vehicle does not issue a braking signal. This automatic braking function can significantly reduce the safety risks caused by pipeline leakage. The intensity of the trailer's automatic braking depends on the degree of pipeline leakage. If the leak is severe, the braking intensity will increase accordingly; if the leak is light, the braking intensity will be relatively small. This adaptive braking intensity design ensures that the trailer can obtain sufficient braking force under different leakage conditions.
In summary, the trailer control valve accurately adjusts the air pressure in the trailer brake chamber by controlling the movement of the piston and the opening and closing of the intake valve and exhaust port to achieve synchronization and stability of the trailer and host vehicle braking. In abnormal situations, it can also ensure that the trailer has a certain braking ability and improve driving safety.
