Patent ID: 11891028
Assignee: BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A method for operating a vehicle with an electrohydraulic brake system comprising a first and second hydraulic brake circuit that are each assigned to hydraulically enable at least one respective wheel brake of the vehicle, the method comprising:
hydraulically decoupling the first brake circuit of the brake system from the second brake circuit;
separating the second brake circuit from an actuating cylinder that is actuatable by a brake pedal, wherein
the actuating cylinder comprises first and second pressure chambers assigned to the first brake circuit and second brake circuit, respectively;

producing a hydraulic connection between the actuating cylinder and the at least one wheel brake assigned to the first brake circuit;
separating the hydraulic connection of the first brake circuit from a hydraulic pressure source that is controllable by a control unit;
switching an outlet valve assigned to the at least one wheel brake of the first brake circuit into an opened position, in which the outlet valve produces a hydraulic connection between the at least one wheel brake of the first brake circuit and a brake fluid vessel;
conveying hydraulic brake fluid from only the first pressure chamber of the actuating cylinder via the first brake circuit and via the opened outlet valve at the at least one wheel brake into the brake fluid vessel;
evacuating hydraulic fluid from only the first pressure chamber of the actuating cylinder, wherein
the vehicle is operable in a manual and an autonomous driving mode; and
during an autonomous driving mode, the brake pedal is brought into an at least partially actuated position; and

evacuating the second pressure chamber of the actuating cylinder via the following steps:
separating the second brake circuit of the brake system from the first brake circuit;
separating the first brake circuit from the actuating cylinder that is actuatable by the brake pedal;
producing a hydraulic connection between the actuating cylinder and the at least one wheel brake assigned to the second brake circuit;
separating the hydraulic connection of the second brake circuit from a hydraulic pressure source that is controllable by a control unit;
switching an outlet valve assigned to the at least one wheel brake of the second brake circuit into an opened position, which outlet valve produces a hydraulic connection between the at least one wheel brake and a brake fluid vessel;
conveying hydraulic brake fluid from only the second pressure chamber of the actuating cylinder via the second brake circuit and via the opened outlet valve at the at least one wheel brake into the brake fluid vessel; and
evacuating hydraulic fluid from only the second pressure chamber of the actuating cylinder.