Patent ID: 7980637

Claim:
A brake control valve including a volume, an emergency vent valve connected to an interface of a pipe bracket, the interface including first and second brake pipe ports and a volume port, the emergency vent valve comprising: a vent valve selectively connecting the first brake pipe port to a vent port; a vent piston controlling the vent valve, the vent piston including a first side connected to the volume port and a second side; an emergency piston including a first side connected to the volume port and a second side connected to the second brake pipe port; an accelerated application valve selectively connecting the volume port and the second brake pipe port to the vent port in response to pressure from the volume port; a discharge valve connected to the emergency piston and selectively interconnecting the second side of the vent piston, the vent port, the volume port and the accelerated application valve as a function of the displacement of the emergency piston; the discharge valve's connection of the vent port to the second side of the vent piston and the volume port is a variable orifice whose opening varies as a function of the displacement of the emergency piston; and the discharge valve disconnects the volume port from the accelerated application valve for the brake release position of the emergency piston, and connects the volume port to the accelerated application valve for the brake apply position of the emergency piston.