Method for detecting changes in the rigidity of a hydraulic brake system
AssigneeRobert Bosch GmbH
InventorsThilo Stephan, Ralf Kinder, Dirk Mahnkopf
Life of this patent
Estimating the term…
Abstract
In a method for detecting air in the brake circuit of a motor vehicle having a hydraulic brake system that has a vacuum brake booster, the pressure prevailing in the vacuum chamber of the vacuum brake booster in the operated and the non-operated states of the brake is measured, and a parameter characteristic of the brake performance is determined as a function of the measured pressure, and the characteristic parameter is compared to a reference value.
Claims12
A method for detecting changes in the rigidity of a hydraulic brake system having a vacuum brake booster, comprising:
- operating a brake and holding the brake constant over a first predefined period of time to determine an operated state of the brake;
- releasing the brake for a second predefined period of time to determine a non-operated state of the brake;
- measuring, in each of consecutive operated state and non-operated state of the brake, a pressure prevailing in a vacuum chamber of the vacuum brake booster, wherein the vacuum chamber includes a diaphragm;
- ascertaining, as a function of the measured vacuum chamber pressures in each of the consecutive operated state and non-operated state of the brake, a characteristic parameter characterizing the brake performance;
- and
- comparing the characteristic parameter to a reference value.
A control unit for detecting changes in the rigidity of a hydraulic brake system having a vacuum brake booster, comprising:
- a measuring arrangement configured to measure, in each of consecutive operated state and non-operated state of the brake, a pressure prevailing in a vacuum chamber of the vacuum brake booster, wherein the vacuum chamber includes a diaphragm;
- an ascertaining arrangement configured to ascertain, as a function of the measured vacuum chamber pressures in each of the consecutive operated state and non-operated state of the brake, a characteristic parameter characterizing the brake performance;
- and
- comparing unit configured to compare the characteristic parameter to a reference value,
- wherein the operated state is determined when the brake is operated and held over a first predefined period of time, and the non-operated state is determined when the brake is released for a second predefined period of time.
Dependencies are inferred from the claim text.