Electronically controllable braking force amplifier maintains control parameter unchanged if difference between driver demand and control parameters does not exceed defined tolerance value

摘要

The braking force amplifier has a vacuum chamber (23) and a pressure chamber (24) separated by a movable wall (22) and a control valve arrangement with an electromagnetic actuator (26) for setting a pressure difference between the chambers and with holding, pressure build-up and pressure decrease settings. A sensor (31) detects a signal correlated with the pressure in a hydraulic cylinder (25) with a hydraulic connection leading to a wheel brake (4) and forming a control parameter. An electronic control unit (ECU) determines a demand parameter taking into account the output of a sensor (11) detecting the driver's demand. The control parameter value remains unchanged if the control difference between the demand and control parameters does not exceed a defined tolerance value.