Method and device for operating a motor vehicle, motor vehicle

A control unit for operating a motor vehicle that includes a hydraulically actuatable wheel brake and an electric drive motor, the control unit comprising a processor, wherein the processor is configured to:

• monitor a driver behavior;
• based on the monitoring, detect an emergency braking operation;
• and
• in response to the detection of the emergency braking operation:
• initiate application of a hydraulic emergency braking torque to gradually increase to reach a target hydraulic emergency braking torque value by activating the wheel brake;
• immediately apply an electrical emergency braking torque by operating the drive motor as a generator causing the electrical emergency braking torque to reach a target electrical emergency braking torque value while the hydraulic emergency braking torque is gradually increased towards the target hydraulic emergency braking torque value;
• and
• after the target electrical emergency braking torque value is reached, and while the hydraulic emergency braking torque is gradually increased towards the target hydraulic emergency braking torque value, control the drive motor to reduce the electrical emergency braking torque, the target hydraulic emergency braking torque value thereafter being reached;
• wherein:
• (a) the control of the drive motor to reduce the electrical emergency braking torque is a start, prior to the target hydraulic emergency braking torque value being reached, of a gradual reduction of the electrical emergency braking torque to 0, without an increase of the electrical emergency braking torque between the start and end of the gradual reduction;
• (b) the electrical emergency braking torque is controlled in response to the detection of the emergency braking operation such that, while the hydraulic emergency braking torque gradually increases to the target hydraulic emergency braking torque value:
• the electrical emergency braking torque initially increases to the target electrical emergency braking torque value in a first period;
• the electrical emergency braking torque is maintained at the target electrical emergency braking torque value in a second period that immediately follows the first period;
• and
• the electrical emergency braking torque is gradually reduced from the target electrical emergency braking torque value in a third period that immediately follows the second period;
• and/or
• (c) the reduction of the electrical emergency braking torque and the activating of the wheel brake are performed such that the target hydraulic emergency braking torque value is reached, at which point a value of the electrical emergency braking torque is reduced to 0.

A vehicle comprising:

• a hydraulically actuatable wheel brake;
• an electric drive motor;
• and
• a processor, wherein the processor is configured to:
• monitor a driver behavior;
• based on the monitoring, detect an emergency braking operation;
• and
• in response to the detection of the emergency braking operation:
• initiate application of a hydraulic emergency braking torque to gradually increase to reach a target hydraulic emergency braking torque value by activating the wheel brake;
• immediately apply an electrical emergency braking torque by operating the drive motor as a generator causing the electrical emergency braking torque to reach a target electrical emergency braking torque value while the hydraulic emergency braking torque is gradually increased towards the target hydraulic emergency braking torque value;
• and
• after the target electrical emergency braking torque value is reached, and while the hydraulic emergency braking torque is gradually increased towards the target hydraulic emergency braking torque value, control the drive motor to reduce the electrical emergency braking torque, the target hydraulic emergency braking torque value thereafter being reached;
• wherein:
• (a) the control of the drive motor to reduce the electrical emergency braking torque is a start, prior to the target hydraulic emergency braking torque value being reached, of a gradual reduction of the electrical emergency braking torque to 0, without an increase of the electrical emergency braking torque between the start and end of the gradual reduction;
• (b) the electrical emergency braking torque is controlled in response to the detection of the emergency braking operation such that, while the hydraulic emergency braking torque gradually increases to the target hydraulic emergency braking torque value:
• the electrical emergency braking torque initially increases to the target electrical emergency braking torque value in a first period;
• the electrical emergency braking torque is maintained at the target electrical emergency braking torque value in a second period that immediately follows the first period;
• and
• the electrical emergency braking torque is gradually reduced from the target electrical emergency braking torque value in a third period that immediately follows the second period;
• and/or
• (c) the reduction of the electrical emergency braking torque and the activating of the wheel brake are performed such that the target hydraulic emergency braking torque value is reached, at which point a value of the electrical emergency braking torque is reduced to 0.