Introduction to the relay valve The relay valve is part of the automobile air brake system. The air inlet of the relay valve is connected to the air reservoir, and the air outlet is connected to the brake air chamber. When the brake pedal is depressed, the output air pressure of the brake valve is used as the control pressure input of the relay valve. Under the action of the control pressure, the air inlet valve is pushed open, so the compressed air enters the brake directly from the air reservoir through the air inlet. The brake air chamber does not need to flow through the brake valve, which greatly shortens the inflation pipeline of the brake air chamber and accelerates the inflation process of the air chamber. Therefore, the relay valve is also called the acceleration valve. Function of relay valve: The relay valve is used at the end of a long pipeline to quickly fill the brake chamber with compressed air from the air reservoir, such as in a trailer or semi-trailer braking system. In the braking system of a truck, the relay valve plays a role in shortening the reaction time and pressure build-up time. Relay valve selection: Generally, differential relay valves are used. Prevent the simultaneous operation of the driving and parking systems, the overlap of forces in the combined spring brake cylinder and the spring brake chamber, thereby avoiding overload of the mechanical transmission components and rapid charging and exhausting of the spring brake cylinder. Reasons for relay valve leakage: Whether the relay valve is leaking under normal conditions or under working conditions, it is generally caused by the lax sealing of the intake valve or exhaust valve, and this is caused by damage to the sealing element or There are impurities and foreign matter produced. Disassembling and cleaning or replacing the sealing components will solve the problem. The working principle of the relay valve: the air reservoir and the brake chamber are generally connected by pipelines only through the brake valve. In this way, the air reservoir inflates the brake chamber and the compressed air is discharged into the atmosphere, both of which must return to the brake valve. When the air reservoir, brake chamber and brake valve are far apart, this roundabout charging and exhausting will cause the lag time of braking and braking to be too long, which is not conducive to timely braking and braking of the car. Timely acceleration. The working principle of the relay valve and the quick release valve came into being under this situation. The working principle of the relay valve is that under normal circumstances, the air inlet is connected to the air reservoir, and the air outlet is connected to the brake air chamber. When the brake pedal is depressed, the output air pressure of the brake valve is used as the control pressure input for the working principle of the relay valve. Under the action of the control pressure, the air inlet valve is pushed open, so the compressed air passes directly from the air reservoir through the air inlet. Entering the brake air chamber without flowing through the brake valve, which greatly shortens the charging pipeline of the brake air chamber and accelerates the charging process of the air chamber. Therefore, the working principle of the relay valve is also called the acceleration valve.