Electro-pneumatic air brake valve and system compatible with a skid

Abstract

A vehicle brake actuation system is disclosed containing fluid pressure to operate brake actuators for effectively combining an electro-pneumatic relay system to function with a skid control system. A first valve is connected in the system for releasing a first impulse of fluid pressure from a first container. A second valve is connected to receive the first impulse from the first container, a second pressure impulse from a second container and to release a thrid pressure impulse from the second container to the actuators. A first sensor senses fluid pressure between the first and second valves and produces a first signal in proportion thereto. A second sensor senses fluid pressure between the second valve and the actuators and produces a second signal in proportion thereto. A first logic circuit receives and compares the first and second signals for discriminately controlling communication of the first, second and third impulses with the second valve. A second or skid control logic circuit is operable to override the first logic circuit to discriminately interrupt communication of the first impulse with the second valve. The second valve has a first port for receiving the first impulse. A second port is connected to receive the second impulse. A first solenoid in the first port is normally open and is operable to close for interrupting the first impulse. A second solenoid is in the second port and is normally closed and operable to open for admitting the second impulse to the valve.