DE102011109697A1 - Method for operating a motor vehicle and driver assistance system for carrying out the method - Google Patents

Abstract

The invention relates to a method for operating a motor vehicle (1), in which it is determined whether a turn is initiated during a journey of the motor vehicle (1) and there is a risk of collision with an oncoming road user (2). In the case of a determined risk of collision, an automatic brake intervention is triggered. In this case, a speed difference and a maximum braking time duration are predetermined and the automatic brake intervention is aborted when the driving speed of the motor vehicle (1) has reduced by the speed difference during the automatic braking intervention, or otherwise, when the duration of the automatic braking intervention reaches the predetermined maximum braking time. Furthermore, the invention relates to a driver assistance system for a motor vehicle (1) for carrying out the method.

Description

The invention relates to a method for operating a motor vehicle, wherein it is determined whether a turn of the motor vehicle is initiated and there is a risk of collision with an oncoming vehicle, and issued in the case of a detected risk of collision, a warning to a driver of the motor vehicle is and under at least one condition, an automatic brake intervention is triggered. Furthermore, the invention relates to a driver assistance system for carrying out the method.

Methods and driver assistance systems are already known in which a driver of a motor vehicle is assisted in driving situations with a change of direction of the motor vehicle in order to avoid collisions with other vehicles or to reduce the consequences of such collisions.

For example, the DE 10 2007 015 032 A1 a method for assessing the criticality of a traffic situation and a device for collision avoidance or collision consequence reduction. In the process, objects are detected that are on a colliding course with their own vehicle. In a traffic situation assessed as critical, a warning is issued and a collision-avoiding or collision-sequence-reducing system intervention is triggered or the engagement threshold for such a system intervention is adapted to the criticality.

The DE 10 2004 057 745 A1 discloses a driving assistance device and a vehicle driving assistance method for aiding a turning or turning operation of a vehicle at an intersection. In this case, information regarding a road, the location of the vehicle, and the surface condition of the road are obtained, and based on this information, a time necessary for completing the cornering or turning operation is determined when the vehicle is in a cornering or cornering state a turn is located. Further, it is determined whether and when a moving object arrives at an oncoming lane of the lane at the location. By comparing the time of arrival of the moving object and the time taken by the vehicle to complete the turn or turn, a crash probability is determined. If there is a risk of collision, assistance is offered to a driver of the vehicle. In particular, in this case, an automatic braking operation is performed under certain conditions.

DE 10 2006 040 331 A1 discloses an apparatus and method for driver information and assistance with a control unit and with driver information and assistance output means, the apparatus being in data and / or signal communication with electronic systems and / or sensors and being based on the available data and data / or signals a recommendation and / or action support for the driver to cope with the current traffic situation can be determined and the driver by means of the output means and / or connected driver assistance systems can be output.

The invention is based on the object to provide an improved method for operating a motor vehicle in driving situations with a change in direction of the motor vehicle. Furthermore, the invention is based on the object of specifying a driver assistance system for carrying out such a method.

The object is achieved according to the invention with regard to the method by the features of claim 1 and with regard to the driver assistance system by the features of claim 10.

Advantageous embodiments of the invention are the subject of the dependent claims.

In the method according to the invention for operating a motor vehicle, it is determined whether a turning operation is initiated during a journey of the motor vehicle and there is a risk of a collision with an oncoming traffic participant, for example with an oncoming vehicle or pedestrian. In the case of a determined risk of collision, an automatic brake intervention is triggered. In this case, a speed difference and a maximum braking time duration are predetermined and the automatic braking intervention is aborted when the driving speed of the motor vehicle has reduced during the automatic braking intervention by the speed difference or, otherwise, when the duration of the automatic braking intervention reaches the maximum braking time.

In the method according to the invention, therefore, it is determined in turning situations of a motor vehicle whether there is a risk of collision with oncoming vehicles and, depending on the situation, an automatic braking intervention is triggered. Furthermore, a collision can be avoided by an automatic braking intervention or its consequences can be reduced, in particular if the driver of the motor vehicle no longer has sufficient time to react effectively to the risk of collision.

According to the automatic braking intervention is aborted when the Driving speed has decreased by a predetermined speed difference, for example by a value lying in the range between 10-40 km / h, but at the latest after a predetermined maximum braking time, for example after about 1 s. As a result, the braking intervention is limited both in terms of time and in its effect. Thus, the driver's control of the vehicle is only temporarily limited and unnecessary effects of the automatic brake intervention are avoided. This is advantageous because an automatic brake intervention, in particular a falsely triggered brake intervention, by limiting the driver's control of the motor vehicle and the consequences of deceleration always brings a security risk, which is reduced by the inventive limitations of the automatic braking intervention.

A further advantage of the method according to the invention is that it does not require any information about a road course or about right of way rules or about intersections equipped with special infrastructure. Furthermore, it is equally applicable to right-hand traffic and left-hand traffic, requiring no change in switching between right-hand traffic and left-hand traffic, and is suitable for all forms and phases of a turning operation, i. H. for turning operations with and without stopping the motor vehicle and thus both when starting and during the passage of a turning trajectory.

In an advantageous embodiment of the invention, a maximum deceleration is also predetermined and the automatic braking intervention is performed such that the delay caused by him delaying the movement of the motor vehicle is limited to the maximum delay.

A deceleration of a movement is understood to mean an acceleration which reduces the speed of the movement. According to this embodiment of the invention, the automatic braking intervention is thus also limited in terms of the delay caused by him. This is advantageous because it allows a controlled braking ("target braking") can be realized on an object. Hereby, a collision avoidance coupled with the smallest possible impairment of the subsequent traffic can be realized.

Advantageously, the braking intervention is only triggered when predetermined conditions are met. In particular, the automatic braking intervention is only triggered when the driving speed of the motor vehicle is within a predetermined speed range.

As a result, the automatic braking intervention can advantageously be restricted to driving speeds characteristic of a turning operation, for example to a speed range which corresponds in particular to the driving speeds customary in inner city areas and at intersections. The speed range includes in particular the range above a predetermined minimum speed, which is for example in the order of magnitude of the walking speed of a pedestrian.

A further embodiment of the invention provides that it is determined for at least one vehicle occupant of the motor vehicle whether it is secured by a safety belt, and that the automatic braking intervention is only triggered when the at least one vehicle occupant is secured by a safety belt. Advantageously, it is determined in a plurality of vehicle occupants, whether all vehicle occupants are secured by a respective safety belt, and the automatic braking intervention is triggered only if this is the case, d. H. the automatic braking intervention is advantageously not triggered when one of the occupants of the vehicle is not strapped.

As a result, it is advantageously possible to avoid injuries to vehicle occupants of the motor vehicle not secured by a safety belt, which could result from an automatic braking intervention.

A further embodiment of the invention provides that a maximum number of automatic brake interventions is specified, after each engine start of a drive motor of the motor vehicle, the automatic braking interventions are counted, and the automatic braking intervention is triggered only if the number of automatic at the time of determining the risk of collision Brake intervention since the last previous engine start is less than the maximum number.

In other words, an automatic brake intervention is only triggered if the number of automatic brake interventions already triggered since the last preceding engine start is less than a predefined maximum number, for example less than one or less than two. As a result, it is advantageously possible to avoid false triggering of automatic brake interventions, which are caused by malfunctions of a driver assistance system, which manifest themselves in unusually frequent triggering of automatic brake interventions. In addition, a repeated triggering of automatic brake interventions can be prevented, which is only caused by a typical for the driver of the motor vehicle driving behavior.

Preferably, to determine a risk of collision, a length and / or a width of the oncoming vehicle are detected, and the movements of the motor vehicle and of the oncoming vehicle are detected and extrapolated.

In this case, collision-relevant movement parameters of the motor vehicle and of the oncoming traffic participant, such as their positions, travel speeds and accelerations and yaw rates, are detected on a time-dependent basis and extrapolated and evaluated on the basis of an object model suitable for determining the risk of collision. As a result, advantageously a collision probability can be determined and used to determine the risk of collision.

Preferably, a maximum curvature of a trajectory of the detected movement of the oncoming traffic participant is also determined and the automatic brake intervention is only triggered if the determined maximum curvature is smaller than a predetermined curvature threshold value.

In other words, an automatic braking intervention in this embodiment of the invention is only triggered when the oncoming road users moves sufficiently straightforward. This advantageously prevents an automatic brake intervention when the oncoming road user performs an avoidance maneuver for collision avoidance or the oncoming road user himself is about to turn off.

Further, it is preferably judged on the basis of the detected movements of the motor vehicle and the oncoming traffic participant, the detected length and / or width of the oncoming road user and vehicle characteristics of the motor vehicle, whether the impending collision can be avoided by actions of the driver of the motor vehicle. The automatic braking intervention is only triggered when the impending collision can not be avoided according to this assessment by actions of the driver of the motor vehicle.

In this case, the object model mentioned above preferably also takes into account options for action of the driver of the motor vehicle and / or of the oncoming traffic participant, for example steering, avoidance, braking or acceleration actions, and assesses whether a collision can be prevented by such actions. In this way, an automatic brake intervention is triggered only if it seems absolutely necessary. As a result, the dangers caused by automatic braking interventions are advantageously further reduced.

Furthermore, the automatic brake intervention is preferably only triggered when a turn maneuver has been detected based on in-vehicle sensors, for example, when the operation of a direction indicator was detected.

As a result, a false triggering of an automatic braking intervention is advantageously prevented if the driver of the motor vehicle does not intend to turn.

In addition, the automatic brake intervention is preferably only triggered when a detection of the oncoming traffic participant meets at least a predetermined quality criterion. Such quality criteria are, for example, a minimum period of time during which the oncoming vehicle is detected, or detection of the oncoming traffic participant by at least two environmental sensors arranged on the motor vehicle.

As a result, an error detection of an oncoming road user is advantageously prevented.

• – Ein Lenkradwinkel und eine Lenkradwinkelgeschwindigkeit einer Lenkung des Kraftfahrzeuges überschreiten jeweils einen vorgegebenen Lenkradwinkelschwellenwert bzw. einen vorgegebenen Lenkradwinkelgeschwindigkeitsschwellenwert;
• – eine von dem Fahrer des Kraftfahrzeuges durch Betätigung eines entsprechenden Steuerungselementes angeforderte Fahrzeugbeschleunigung überschreitet einen vorgegebenen Beschleunigungsschwellenwert;
• – der entgegenkommende Verkehrsteilnehmer wird nicht mehr erfasst;
• – eine Fahrdynamikregelung des Kraftfahrzeuges führt einen Bremseingriff durch;
• – ein Bremsassistenzsystem des Kraftfahrzeuges weist eine Fehlfunktion auf.

Preferably, a triggered automatic brake intervention is terminated by a driver initiation or an automatic brake intervention is not triggered until at least one of the following conditions has been met:

• A steering wheel angle and a steering wheel angular velocity of a steering of the motor vehicle each exceed a predetermined steering wheel angle threshold value or a predetermined steering wheel angular velocity threshold value;
• A vehicle acceleration requested by the driver of the motor vehicle by actuation of a corresponding control element exceeds a predetermined acceleration threshold value;
• - the oncoming road user is no longer recorded;
• - A vehicle dynamics control of the motor vehicle performs a braking intervention;
• - A brake assist system of the motor vehicle has a malfunction.

Thereby an automatic braking intervention is aborted or not triggered when the driver of the motor vehicle carries out itself actions for collision avoidance or Kollisionsfolgenminderung by an evasive maneuver or acceleration of the motor vehicle. This advantageously avoids that these options for action of the driver are impaired. Furthermore, an automatic braking intervention is aborted or not triggered when the oncoming traffic participant is not detected, which is advantageous to respond to a fault detection or turning or avoiding the oncoming road user. In addition, a braking intervention by a driving dynamics control of the motor vehicle is given priority over an automatic braking intervention according to the invention in order not to impair the braking intervention by the vehicle dynamics control.

Advantageously, the release of a warning to the driver of the vehicle is triggered before the triggering of the automatic braking intervention. By the warning, the driver is advantageously made aware of the risk of collision, so that he can initiate measures to avoid a collision or to reduce collision consequences. However, it is also conceivable, in particular in situations in which the driver has little time left for the initiation of collision-avoiding or collision-sequence-reducing measures, to trigger the warning simultaneously with the braking intervention.

In a further embodiment of the invention, further safety measures are activated simultaneously with or alternatively even before the issuing of a warning to the driver, for example a prefilling of a brake or so-called pre-safe measures, such as a tightening of safety belts, a closure of a sliding roof and / or a seat adjustment of vehicle seats in a position in which the vehicle occupants are at least vulnerable to injury.

This advantageously allows a quick reaction to a detected risk of collision and reduces a risk of injury to the vehicle occupants.

An inventive driver assistance system for a motor vehicle comprises redundant environmental sensors arranged on the motor vehicle for detecting a vehicle environment in front of the motor vehicle, an output unit for issuing warnings to the driver, brake intervention means for controlling the brakes of the motor vehicle and a control unit. The control unit is designed to evaluate the signals detected by the environmental sensors with regard to the risk of a collision with an oncoming road user and with regard to the output of warnings to the driver and the execution of automatic braking interventions as a function of a determined risk of collision and to control the output unit and the brake intervention means in Dependence on the results of the evaluation.

Such a driver assistance system makes it possible to carry out the method according to the invention with the advantages mentioned above. The environmental sensors allow the detection of escaping vehicles. On the one hand, the use of redundant environmental sensors is advantageous because it can compensate for a failure of one or more of these environmental sensors. On the other hand, the signals detected by redundant environmental sensors can be compared with each other. As a result, error detections due to the signals of an environmental sensor can be noticed and thus false triggering of warnings or automatic brake interventions can be advantageously avoided or reduced.

Particularly suitable as redundant environmental sensors are a stereo camera in conjunction with a near-field radar and a far-range radar. The stereo camera advantageously allows a very accurate stereoscopic determination of movement and object parameters of an oncoming road user. The radar system is advantageously used for protection by redundant sensors.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 in a plan view, a first turning operation of a motor vehicle, in which an automatic braking operation is triggered,

2 in a plan view, a second turning operation of a motor vehicle, in which an automatic braking operation is triggered,

3 in a plan view, a third turning operation of a motor vehicle, in which an automatic braking operation is triggered,

4 in a plan view, a fourth turning operation of a motor vehicle, in which an automatic braking operation is triggered,

5 in a plan view a fifth turn of a motor vehicle, in which no automatic braking is triggered,

6 in a plan view, a sixth turn of a motor vehicle, in which no automatic braking is triggered,

7 in a plan view, a seventh turning operation of a motor vehicle in which no automatic braking operation is triggered,

8th in a plan view, an eighth turn of a motor vehicle, in which no automatic braking is triggered,

9 in a plan view of a traffic situation in which no automatic braking is triggered and

10 a block diagram of a driver assistance system.

Corresponding parts are provided in all figures with the same reference numerals.

The 1 to 9 show various turning operations of a motor vehicle 1 in which the motor vehicle 1 a vehicle 2 accommodates. The illustrated turns take place at a crossroads 3 instead of two streets 4 . 5 cross. At the same time, the motor vehicle travels 1 and the oncoming vehicle 2 before the turn a first street 4 in opposite directions and the motor vehicle 1 is about to start from the first street 4 in the second street 5 turn.

The 1 to 9 each show the motor vehicle 1 and the oncoming vehicle 2 in two successive vehicle positions 1.1 . 1.2 respectively. 2.1 . 2.2 and in an extrapolated vehicle positioning 1.3 respectively. 2.3 , which is shown in dashed lines. A vehicle positioning of a vehicle is defined in each case by the position of the center of gravity, the dimensions and the orientation of the longitudinal axis of the vehicle.

During a drive of the motor vehicle 1 it is determined whether a turn is initiated and thereby a risk of collision with an oncoming vehicle 2 consists. To initiate a turn of the motor vehicle 1 be recognized, suitable driving parameters of the motor vehicle 1 predetermined and evaluated, in particular temporal courses of a driving speed and a steering wheel angle of the motor vehicle 1 and / or the operation of a direction indicator. A risk of collision with an oncoming vehicle 2 to recognize a vehicle environment in front of the motor vehicle 1 by means of the motor vehicle 1 arranged redundant environmental sensors detected and detected by these environmental sensors signals are evaluated. In this case, an object recognition is performed to oncoming vehicles 2 and to recognize their latitudes and longitudes, and the movements of an oncoming vehicle 2 and the motor vehicle 1 are determined and extrapolated. Information about intersections is not needed. The motion profile of the two vehicles is crucial for the detection of the risk of collision during a turn. The method therefore works not only when turning in intersections but also when turning into a driveway.

In the case of a determined risk of collision, a warning to the driver of the motor vehicle 1 output. Furthermore, under predetermined conditions, an automatic brake intervention for braking the motor vehicle 1 triggered. This automatic braking intervention is limited in time and in its effect. The automatic braking intervention is aborted at the latest after a predetermined maximum braking time and it is already canceled before when the speed of the motor vehicle 1 has decreased by a predetermined speed difference since the initiation of the braking intervention. Also conceivable is a limitation of the automatic braking intervention such that a predetermined maximum delay is not exceeded. The maximum delay is advantageously specified depending on the situation, for example, speed-dependent.

Among the conditions under which an automatic braking intervention is triggered include, among other things, that the driving speed of the motor vehicle 1 is located in the determination of the risk of collision in the defined speed range and that the oncoming vehicle 2 moved sufficiently straight. To judge the straightness of the movement of the oncoming vehicle 2 becomes the maximum curvature of a trajectory of the sensed motion of the oncoming vehicle 2 determined and compared with a predetermined curvature threshold.

• – Ein Lenkradwinkel und eine Lenkradwinkelgeschwindigkeit einer Lenkung des Kraftfahrzeuges 1 überschreiten jeweils einen vorgegebenen Lenkradwinkelschwellenwert bzw. einen vorgegebenen Lenkradwinkelgeschwindigkeitsschwellenwert;
• – eine von dem Fahrer des Kraftfahrzeuges 1 durch Betätigung eines entsprechenden Steuerungselementes, z. B. eines Fahrpedals, angeforderte Fahrzeugbeschleunigung überschreitet einen vorgegebenen Beschleunigungsschwellenwert;
• – das entgegenkommende Fahrzeug 2 wird nicht mehr erfasst;
• – eine Fahrdynamikregelung des Kraftfahrzeuges 1 führt einen Bremseingriff durch;
• – ein Bremsassistenzsystem des Kraftfahrzeuges 1 weist eine Fehlfunktion auf;
• – es ist kein Fahrtrichtungsanzeiger des Kraftfahrzeuges 1 eingeschaltet;
• – ein Fahrzeuginsasse des Kraftfahrzeuges 1 ist nicht durch einen Sicherheitsgurt gesichert;
• – der Fahrer des Kraftfahrzeuges 1 kann die Kollision durch eine entsprechende Handlung, z. B. durch Bremsen, Ausweichen oder Beschleunigen, noch selbsttätig vermeiden.

However, an automatic brake intervention is not triggered or an already initiated brake intervention is aborted if at least one of the following conditions is met:

• - A steering wheel angle and a steering wheel angular velocity of a steering of the motor vehicle 1 each exceed a predetermined steering wheel angle threshold and a predetermined steering wheel angular speed threshold, respectively;
• - One of the driver of the motor vehicle 1 by actuating a corresponding control element, for. B. an accelerator pedal, requested vehicle acceleration exceeds a predetermined acceleration threshold;
• - the oncoming vehicle 2 is no longer recorded;
• - A vehicle dynamics control of the motor vehicle 1 performs a braking intervention;
• - A brake assist system of the motor vehicle 1 has a malfunction;
• - It is not a direction indicator of the motor vehicle 1 switched on;
• - A vehicle occupant of the motor vehicle 1 is not secured by a safety belt;
• - the driver of the motor vehicle 1 can the collision by a corresponding action, for. B. by braking, dodging or accelerating, still avoid automatically.

The 1 to 4 each show a turn in which an automatic brake intervention is triggered. The oncoming vehicle is moving 2 almost straightforward and the vehicle 1 turns in the direction of the oncoming vehicle 2 from. The extrapolated movements of the motor vehicle 1 and the oncoming vehicle 2 indicate a collision.

The 1 and 2 represent each turning operations in which a collision when turning left of the motor vehicle 1 in a legal transaction threatens. 1 shows a situation in which the two vehicles 1 . 2 collide head-on with each other. 2 shows a situation in which the motor vehicle 1 with a front side edge of the oncoming vehicle 2 collided. 3 represents a turning process, in which a collision in the right turn of the motor vehicle 1 threatens in a left-hand traffic. 4 represents a turning process, in which a collision in the right turn of the motor vehicle 1 in a legal traffic threatens, being the oncoming vehicle 2 a bicycle is. Not shown is a situation in which the motor vehicle 1 analogous to the situation according to 2 with the rear side flank or the rear of the oncoming vehicle 2 collides, such a situation will be in the same way as the other situations according to the 1 to 4 treated.

The 5 to 9 each show a turn in which no automatic braking intervention is triggered.

5 shows a turning process in which the extrapolated movements of the motor vehicle 1 and the oncoming vehicle 2 identify that the oncoming vehicle 2 the trajectory of the motor vehicle 1 only after the turn of the vehicle 1 crosses, so that no risk of collision is determined.

6 shows a turning process in which the extrapolated movements of the motor vehicle 1 and the oncoming vehicle 2 identify that the oncoming vehicle 2 the trajectory of the motor vehicle 1 already before the turning of the motor vehicle 1 crosses, so that no risk of collision is determined.

The 7 and 8th show each turning operations in which the motor vehicle 1 in a legal traffic turns to the left and no automatic braking intervention is triggered. The oncoming vehicle bends 2 in 7 collision-free to the left.

9 shows a traffic situation in which despite collision danger no automatic brake intervention is triggered because the motor vehicle 1 does not initiate a turn and because the oncoming vehicle 2 even turns.

10 shows a block diagram of a driver assistance system 6 for carrying out the method according to the invention. It includes as on the motor vehicle 1 arranged redundant environmental sensors 7 . 8th . 9 , for example, a stereo camera 7 , a long-range radar 8th and a near-field radar 9 , for detecting a vehicle environment in front of the motor vehicle 1 , an output unit 10 for issuing warnings to the driver of the motor vehicle 1 , Brake intervention 11 for controlling the brakes of the motor vehicle 1 and a control unit 12 for controlling the issuing of warnings and the triggering of automatic brake interventions. The brake intervention 11 are in a vehicle dynamics control 13 of the motor vehicle 1 integrated.

From the environmental sensors 7 . 8th . 9 detected signals 15 become the control unit 12 supplied and from this in terms of the risk of collision with an oncoming vehicle 2 evaluated. Further, the control unit 12 Steering wheel angle sensor signals 16 a steering angle sensor 17 and vehicle operating parameters 18 the vehicle dynamics control 13 , in particular for actuating an accelerator pedal of the motor vehicle 1 and to the vehicle dynamics control 13 performed brake interventions supplied. Depending on the evaluation of the signals 15 the environmental sensors 7 . 8th . 9 , the steering wheel angle sensor signals 16 and the vehicle operating parameters 18 generates the control unit 12 Output unit control signals 19 for controlling the output unit 10 and brake intervention control signals 20 for controlling the brake intervention 11 ,

LIST OF REFERENCE NUMBERS

1

motor vehicle

1.1

first vehicle positioning of the motor vehicle

1.2

second vehicle positioning of the motor vehicle

1.3

extrapolated vehicle positioning of the motor vehicle

2

oncoming vehicle

2.1

first vehicle positioning of the oncoming vehicle

2.2

second vehicle positioning of the oncoming vehicle

2.3

extrapolated vehicle positioning of the oncoming vehicle

3

intersection

4

first Street

5

second Street

6

Driver assistance system

7

stereo camera

8th

Long-range radar

9

short-range radar

10

output unit

11

Brake engagement means

12

control unit

13

electronic stability program

15

signal

16

Steering angle sensor signal

17

Steering angle sensor

18

Vehicle operating parameters

19

Output unit control signal

20

Braking intervention control signal

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102007015032 A1 [0003]
• DE 102004057745 A1 [0004]
• DE 102006040331 A1 [0005]

Claims (10)

Method for operating a motor vehicle ( 1 ), which determines whether during a journey of the motor vehicle ( 1 ) a turning process is initiated and thereby a risk of collision with an oncoming road user ( 2 ), and in which in the case of a determined risk of collision, an automatic braking intervention is triggered, characterized in that a speed difference and a maximum braking time duration are predetermined and the automatic braking intervention is aborted when the driving speed of the motor vehicle ( 1 ) has reduced by the speed difference during the automatic brake application, or otherwise, when the duration of the automatic brake application reaches the maximum brake time. Method according to Claim 1, characterized in that a maximum deceleration is predetermined and the automatic brake intervention is carried out in such a way that the delay in the movement of the motor vehicle caused by it ( 1 ) is limited to a situation-dependent maximum delay. Method according to one of the preceding claims, characterized in that a speed range is specified and the automatic brake intervention is only triggered when the driving speed of the motor vehicle ( 1 ) is within this speed range. Method according to one of the preceding claims, characterized in that for at least one vehicle occupant of the motor vehicle ( 1 ) is determined whether it is secured by a safety belt, and the automatic braking intervention is triggered only if the at least one vehicle occupant is secured by a safety belt. Method according to one of the preceding claims, characterized in that a maximum number of automatic brake interventions is specified, after each engine start of a drive motor of the motor vehicle ( 1 ) the automatic braking interventions are counted, and the automatic braking intervention is triggered only if at the time of determining the risk of collision, the number of automatic braking interventions since the last previous engine start is less than the maximum number. Method according to one of the preceding claims, characterized in that for determining a risk of collision, a length and / or a width of the oncoming road users ( 2 ) and / or the movements of the motor vehicle ( 1 ) and the oncoming road user ( 2 ) and extrapolated. A method according to claim 6, characterized in that a curvature threshold is specified, a maximum curvature of a trajectory of the detected movement of the oncoming traffic participant ( 2 ) is determined and the automatic braking intervention is triggered only if the determined maximum curvature is smaller than the curvature threshold. A method according to claim 6 or 7, characterized in that on the basis of the detected movements of the motor vehicle ( 1 ) and the oncoming road user ( 2 ), the recorded length and / or width of the oncoming vehicle ( 2 ) and vehicle characteristics of the motor vehicle ( 1 ) is judged whether the impending collision by actions of the driver of the motor vehicle ( 1 ) can be avoided, and that the automatic braking intervention is triggered only if the imminent collision according to this assessment by acts of the driver of the motor vehicle ( 1 ) can not be avoided. Method according to one of the preceding claims, characterized in that the automatic braking intervention is canceled or not triggered when at least one of the following conditions is met: - a steering wheel angle and a steering wheel angular velocity of a steering of the motor vehicle ( 1 ) each exceed a predetermined steering wheel angle threshold and a predetermined steering wheel angular speed threshold, respectively; - one of the driver of the motor vehicle ( 1 ) requested by actuation of a corresponding control element vehicle acceleration exceeds a predetermined acceleration threshold; - the oncoming vehicle ( 2 ) is no longer recorded; A vehicle dynamics control of the motor vehicle ( 1 ) performs a braking intervention; A brake assist system of the motor vehicle ( 1 ) has a malfunction. Driver assistance system for a motor vehicle ( 1 ) for carrying out the method according to one of the preceding claims, comprising on the motor vehicle ( 1 ) environmental sensors ( 7 . 8th . 9 ) for detecting a vehicle environment in front of the motor vehicle ( 1 ), an output unit ( 10 ) for issuing warnings to the driver, brake intervention means ( 11 ) for controlling brakes of the motor vehicle ( 1 ) and a control unit ( 12 ) to Evaluation of the environmental sensors ( 7 . 8th . 9 ) detected signals ( 15 ) with regard to the risk of collision with an oncoming vehicle ( 2 ) and with regard to the issuing of warnings to the driver and the execution of automatic braking interventions as a function of an ascertained risk of collision and for controlling the output unit ( 10 ) and the braking intervention means ( 11 ) depending on the results of the evaluation.

Images