Brake pressure modulator and use of a brake pressure modulator

Abstract

A brake pressure modulator () includes a relay valve () for controlling a supply of pressurized air from a primary source (II) to at least one brake actuator (), a first valve sub-unit () configured to be electronically actuated and configured to receive a primary control pressure from the primary source (II) intended for operating the relay valve (), and a second valve unit () configured to receive a secondary control pressure from a secondary source ('BST') and at least part of the primary control pressure from the primary source (II) and to transmit either the primary control pressure or the secondary control pressure to the relay valve (). When the secondary control pressure is transmitted to the relay valve (), the primary control pressure from the primary source (II) is disconnected.