Road vehicle brake system actuating device and method for holding the vehicle stationary on sloped surfaces
AssigneeDaimlerChrysler AG
InventorsJoachim Nell, Manfred Steiner
Life of this patent
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Abstract
In traffic-related stationary phases, a drive ratio of the transmission remains engaged with the engine running on a road vehicle equipped with automatic transmission. The service brake automatically remains activated for a short time after the vehicle has come to a halt as a result of a targeted braking operation. Thereby, the driver is allowed to remove his/her foot from the brake pedal, and the vehicle can be held stationary in a reliable manner on a flat or sloping road surface. This holding braking mode of the vehicle service brake system is cancelled when the driver actuates the accelerator pedal whose position is monitored by a switch.
Claims24
A device for automatic actuation of a hydraulic brake system of a road vehicle for maintaining the road vehicle in a stationary condition throughout traffic-related stationary phases by coupling automatically brake pressure from a brake-pressure source actuatable without driver intervention into at least one wheel brake of the road vehicle, comprising a brake-pressure control device configured to process sensor output signals of a sensor arrangement in accordance with predetermined actuation criteria while an engine of the road vehicle is running and with the road vehicle in the stationary condition achieved after a braking operation, and to provide automatic continuation of a stationary braking operation, in which, after a delay time period of defined length after the road vehicle has come to a stop has passed, a brake pressure sufficient to keep the vehicle reliably in the stationary condition is adapted to be coupled into the at least one wheel brake used for the stationary braking operation, and when driving is resumed, is detectable from a selected combination of the sensor output signals, controls release of the at least one wheel brake previously used for the stationary braking operation, wherein the brake-pressure control device is configured to trigger the automatic stationary braking operation only if, within the delay time period, the driver performs an actuating action which can be recognized as a driver's desire for triggering of automatic stationary braking and is detectable by the sensor arrangement, and provides termination of the automatic stationary braking mode only if, in addition to the sensor output signals of the sensor arrangement which reveal the driver's desire for resumption of the driving mode, there are also present sensor output signals which, again with reference to the predetermined actuation criteria, fulfill safety-relevant secondary conditions.
Method for automatic actuation of a hydraulic brake system of a road vehicle for maintaining the road vehicle in a stationary condition for the duration of traffic-related stationary phases, comprising the steps of coupling automatically brake pressure into at least one wheel brake of the road vehicle;
- processing sensor output signals of a sensor arrangement in accordance with predetermined criteria while an engine of the road vehicle is running and with the vehicle in a stationary condition achieved after a braking operation to provide automatic continuation of the stationary braking operation;
- coupling, after a delay time period of defined length after the vehicle has come to a stop has passed, a brake pressure sufficient to keep the road vehicle reliably in the stationary condition into the at least one wheel brake used for the stationary braking operation;
- detecting when driving is resumed from a selected combination of the sensor output signals;
- controlling the release of the at least one wheel brake previously used for the stationary braking operation when driving is resumed;
- triggering the automatic stationary braking operation only if, within the delay time period, the driver performs an actuating action which can be recognized as a driver's desire for triggering of automatic stationary braking;
- and providing the ending of the automatic stationary braking mode only if, in addition to the sensor output signals of the sensor arrangement which reveal the driver's desire for resumption of the driving mode, sensor output signals are present which, again with reference to the predetermined criteria, fulfill safety-relevant secondary conditions.
Dependencies are inferred from the claim text.