Patent ID: 6422123
Filing Date: 2002-07-23
Classification: B60T

Abstract:
An electronically controllable brake booster, with:vacuum chamber and a pressure chamber which are separated from each other by a movable wall, a control valve arrangement being capable of adjusting a pressure difference between the pressure chamber and vacuum chamber, an electromagnetic actuation unit for actuating the control valve arrangement, and a control unit for controlling a current flowing through the electromagnetic actuation unit, wherein the control valve arrangement is capable to assume, as a function of the current flowing through the electromagnetic actuation unit means, a holding position in which the current ranges between a higher value and a lower value without the control valve arrangement leaving the holding position, a first pressure changing position in which the current is higher than the higher value and a second pressure changing position in which the current is lower than the lower value, characterised in that the control unit is adapted to sense a value which is characteristic for an actual pressure characteristic in the pressure chamber, checking the actual pressure characteristic for an existence of periodic oscillation components of a predetermined frequency band with a predetermined minimum amplitude, and decrease the current for the first pressure changing position by a first predetermined value and to increase the current for the second pressure changing position by a second predetermined value upon the existence of the periodic oscillation components.