DE102018217486A1 - Method for operating a cruise control system of a motor vehicle - Google Patents

Abstract

The invention relates to a method (2) for operating a cruise control system (4) of a motor vehicle (6). A speed (34) of the motor vehicle (6) is controlled to a desired speed (30), and a distance (46) to a preceding further motor vehicle (40) is determined. Then, if the distance (46) is less than a threshold (48), a warning (52) is issued. The invention further relates to a cruise control system (4) of a motor vehicle (6) and a motor vehicle (6).

Description

The invention relates to a method for operating a cruise control system of a motor vehicle. Furthermore, the invention relates to a cruise control system of a motor vehicle and a motor vehicle.

To increase comfort, motor vehicles usually have cruise control systems. By a driver of the motor vehicle, a certain desired speed is set, and by means of the cruise control system, a drive of the motor vehicle is controlled to the desired speed. In this case, for example, an energy supply to the drive is regulated. Also, usually a selection of a particular translation, so in particular a selection of a gear, if the motor vehicle has an automated transmission. When driving downhill, for example, a comparatively low gear is selected in order to be able to maintain the desired speed due to a drag torque of the drive. An active actuation of a brake system, however, usually does not take place by means of the cruise control system.

In addition, automatic distance control are known in which also a desired speed is set. If an object appears in the travel path of the motor vehicle, for example a vehicle driving ahead in a slower manner, the vehicle speed is automatically throttled, so that a certain minimum distance to the preceding vehicle is not undershot. If the vehicle traveling in front of the vehicle leaves the lane, it is again regulated to the original desired speed and the motor vehicle is thus accelerated at the desired speed. Due to such a system, on the one hand, comfort and, on the other hand, safety is increased because no braking intervention or other operation is required on the part of the driver.

In such an automatic distance control, it is thus imperative that the vehicle in front is reliably detected. For this purpose, a comparatively cost-intensive radar sensor is usually used. Furthermore, active braking interventions are carried out by means of the automatic distance control. For this purpose, a comparatively cost-intensive checking of the function during production is necessary, for example, to preclude an uncontrolled deceleration or other interference with further assistance systems of the motor vehicle. Also, a relatively expensive certification is required.

In an automatic distance control, it is also possible that the driver wants to overtake a preceding slower motor vehicle. Here, the motor vehicle approaches the vehicle in front driving up to a certain distance, which is freely selected by the driver. If this is reached, the driver usually operates a steering wheel of the motor vehicle to change the lane. If, however, the distance estimated by the driver is less than the distance predetermined by the automatic distance control, it is possible that the lane change or before a braking intervention by the automatic distance control, so that the motor vehicle is braked automatically when changing lanes. On the one hand, this reduces the comfort for the driver of the motor vehicle. On the other hand, there is the danger that an additional motor vehicle approaching in the further lane collides with the latter due to the braking maneuver of the motor vehicle.

To avoid this, some motor vehicles have, for example, both a cruise control system and an automatic distance control. If, for example, several such overtaking operations are to be carried out, wherein the speed of the motor vehicle should be substantially constant, the automatic distance control is deactivated and the cruise control system activated. In this case, it is possible that the driver forgot after the overtaking operations to re-enable the automatic distance control, so that security is reduced.

The invention has for its object to provide a particularly suitable method for operating a cruise control system and a particularly suitable cruise control system of a motor vehicle and a particularly suitable motor vehicle, advantageously increased security and / or manufacturing costs are reduced.

With regard to the method, this object is achieved by the features of claim 1, with respect to the cruise control system by the features of claim 6 and in terms of the motor vehicle by the features of claim 7 according to the invention. Advantageous developments and refinements are the subject of the respective subclaims.

The method is used to operate a cruise control system of a motor vehicle. The motor vehicle is for example a commercial vehicle. However, the motor vehicle is particularly preferably a passenger car (PKW). The motor vehicle has a drive for the propulsion, for example an internal combustion engine, an electric motor or a combination thereof.

By means of the cruise control system, the motor vehicle is controlled to a desired speed when actuated. For this purpose, the cruise control system is suitable, in particular provided and set up. By means of the cruise control system is advantageously carried out only an influencing a drive train. In other words, for example, an energy supply is regulated. In particular, a fuel supply to the eventual internal combustion engine is regulated, if present. Alternatively, for example, an energization of an electric motor is set / regulated.

Preferably, a gear (gear) of a transmission is selected, if the transmission is designed automated. The transmission is in particular driven by the internal combustion engine and / or the electric motor. Conveniently, the drive train is in operative connection with at least some wheels of the motor vehicle, which are thus driven by means of the drive train.

Particularly preferred by means of the cruise control system ("Cruise Control") no deceleration. In other words, it is not possible by means of the cruise control system to perform braking interventions or to decelerate the motor vehicle, with the exception of any drag torque of the drive train. Alternatively, in particular, a deceleration of the motor vehicle by means of the cruise control system to the desired speed, for which the braking system is suitably controlled by means of the cruise control system. The cruise control system has a suitable interface in particular for this purpose. During operation, only the brake system is influenced as a function of the speed of the motor vehicle with respect to the desired speed and / or as a function of the speed / desired speed. In summary, during operation by means of the cruise control system, no (significant) influencing of a brake system of the motor vehicle takes place. Thus, only comparatively low demands on the safety of the cruise control system are present, which is why production costs are reduced.

The method provides that a speed of the motor vehicle is regulated to a desired speed. For this purpose, in particular the energy supply to the drive is set. Conveniently, an electrical current is regulated an electrical voltage and / or a fuel supply. The desired speed is, for example driver selectable and conveniently created by means of a driver input. Suitably, the desired speed is substantially steplessly adjustable or in certain steps, for example 10 km / h, 5 km / h and / or 1 km / h increments. Appropriately, the speed is controlled to the desired speed until an input is made, which is made in particular by the driver of the motor vehicle. In particular, the desired speed is deleted or the cruise control system is deactivated. Alternatively, for example, if the control deviations are too great, in particular if the motor vehicle accelerates, in particular when the vehicle is descending, the method is terminated.

The method further provides that a distance of a preceding further motor vehicle is determined. In other words, the preceding vehicle is first detected and subsequently determined the distance. The preceding further motor vehicle is referred to hereinafter in particular merely as another motor vehicle. The other motor vehicle moves in the same direction as the motor vehicle and is in the direction of travel before this.

Then, if the distance is less than a limit, a warning is issued. In other words, the distance is monitored, and the warning is issued when the distance is below the limit, that is less than the limit. The distance is, for example, constant or dependent on the speed of the motor vehicle. Suitably, the distance corresponds to the distance covered by the motor vehicle in 2 seconds, 1.5 seconds or 1 second. In particular, the distance is between 30 m and 1 m, between 20 m and 2 m and for example between 5 m and 10 m.

Due to the warning, the driver of the motor vehicle is warned of the driving ahead further motor vehicle. Consequently, if the preceding motor vehicle has a lower speed than the desired speed, the motor vehicle would collide with the further motor vehicle if it continues to move at the desired speed. Due to the warning, the driver of the motor vehicle is advised to make an adjustment so that the collision can be avoided. Thus, a security is increased. Also, for example, when the driver of the motor vehicle consciously approaches the preceding motor vehicle to be able to overtake it, for example, it is not distracted unnecessarily in the overtaking process. Thus, the desired speed can be maintained, especially if due to the Lane change approaches an additional motor vehicle. Consequently, a security or at least a perceived safety for the driver of the motor vehicle is increased.

Since the cruise control system itself does not make any braking interventions or merely intervenes as a function of the desired speed and thus downshifts the motor vehicle to the desired speed, reliable detection of objects in the surroundings of the motor vehicle, such as the vehicle ahead, is not required. Thus, a certification and a comparatively cost-intensive review and a relatively costly testing of the cruise control system is not necessary, which is why production costs are reduced. In other words, for example, the requirements imposed on automatic distance control need not be met. In particular, the requirements for reliability are different.

Preferably, the warning is output in an interior of the motor vehicle. Conveniently in the same interior, in which there is also the driver of the motor vehicle. In particular, in this case the warning is optically output, for example by means of a display. For example, the display is part of the speed control system or the cruise control system has an interface for the display. Alternatively or in combination, the warning is emitted acoustically in the interior. Appropriately, this is a buzzer or a speaker used. For example, the buzzer / speaker is part of the cruise control system or the cruise control system has an interface for this. Expediently, the speed control system is signal-wise coupled to a bus system of the motor vehicle, which is, for example, a Flexray bus system, a Lin bus system or a Can bus system.

Due to the output of the warning in the interior, the driver is requested to take over control of the motor vehicle and in particular to tune the speed of the motor vehicle to the preceding motor vehicle. If, for example, the driver is not focused on the environment, in particular due to the regulation of the speed of the motor vehicle by means of the cruise control system, this is due to the warning reminded that the other motor vehicle is present. In this case, due to the output in the interior of an energy demand is relatively low, and a disturbance of the driver takes place only to a small extent, especially if this has already registered the other motor vehicle and, for example, would like to overtake.

Alternatively or in combination, the warning is output haptically. For example, there is a vibration of a steering wheel. Particularly preferred, however, a brake pressure is used as a warning. Here, a brake system of the motor vehicle is operated comparatively short. In particular, the actuation is less than 1 second, 0.5 seconds or 0.1 seconds. In other words, there is no significant deceleration of the motor vehicle, only a brief actuation of the brake, so that the motor vehicle is vibrated relatively short. Thus, the driver of the motor vehicle is pointed to the further motor vehicle. Consequently, the driver is made aware of the further motor vehicle, in particular if the driver is distracted or briefly fallen asleep. If the driver wishes to overtake the further motor vehicle, there is no uncontrolled movement of the motor vehicle due to the comparatively short actuation of the brake, and the motor vehicle is not or at least not excessively braked, for which reason the overtaking process can proceed essentially undisturbed.

In particular, as a warning, the brake pressure will only be output if the distance is smaller than a second limit value. In other words, the warning is preferably emitted visually and / or acoustically into the interior of the motor vehicle if the distance is smaller than the limit value. If the distance is smaller than the second limit, which is smaller than the limit value, the brake pressure is additionally used as a warning.

Alternatively or in combination with this, for example, the regulation to the desired speed is ended as a warning. For example, the cruise control remains active or the cruise control system is deactivated or placed in a standby mode. At least there is no further regulation to the desired speed. In particular, by means of the cruise control system in this case no further influence of the drive or other component of the drive train. If the driver has already registered and wants to overtake the further motor vehicle, the driver adjusts the speed of the motor vehicle accordingly, in particular by means of actuating a foot pedal. Thus, at a termination of the control to the desired speed for the driver substantially no loss of comfort can be determined. If, for example, the driver of the motor vehicle was distracted and the further motor vehicle has not yet registered, the distance to the further motor vehicle is not reduced or at least not reduced to the same extent due to the termination of the control to the desired speed, so that at least a time span up to one Collision is prolonged. Due to the extended Time span is thus sufficient time for the driver to brake the motor vehicle, for example, or to divert it away from the further motor vehicle.

For example, as a warning or in addition a brake system prefilled, so expediently creates a brake pressure or at least increased. For example, any brake pads are moved up to a brake slide, preferably no braking is made. Due to the pre-filling a slight actuation of any brake pedal for triggering a comparatively strong braking, in particular a so-called full braking is sufficient. Thus, the motor vehicle can be delayed substantially comparatively strong by the driver, if he had not registered the preceding vehicle.

In particular, the preceding motor vehicle is detected by means of a camera, which is directed in a direction of travel of the motor vehicle. Thus, manufacturing costs are reduced. In particular, the camera is suitable, in particular provided and set up to recognize objects. In other words, the camera is used for object recognition. For example, the camera also performs another function, such as traffic sign recognition. Alternatively or in combination with this, the camera is used, for example, for an emergency brake assistant or as a parking aid. These functions are essentially independent of the cruise control system. Due to the multiple use of the camera manufacturing costs are reduced. Also, a weight of the motor vehicle is reduced because no additional sensor is installed for the process.

Alternatively or in combination with this, the further motor vehicle is detected, for example, by means of a TOF sensor ("time of flight"). The sensor used is expediently an ultrasonic sensor, a lidar sensor or a radar sensor. Thus, the detection of the further motor vehicle is substantially independent of environmental conditions. In particular, the sensor, preferably the radar sensor, is a component of an automatic distance control ("Adaptive Cruise Control", ACC). In other words, the sensor is (also) part of a so-called "Adaptive Cruise Control" (ACC).

If the automatic distance control is activated, the cruise control system is deactivated. Here, in particular, the desired speed is specified by the driver and controlled by the automatic distance control, the motor vehicle to the desired speed. In this case, it is additionally monitored by means of the automatic distancing, that a distance to the possible preceding further motor vehicle is not less than a limit distance, which is expediently greater than the limit value. For example, the limit distance is selectable by the driver. If the distance is less than the limit distance, the speed of the motor vehicle is throttled to the speed of the further motor vehicle, which moves on a possible lane of the motor vehicle by means of the automatic distance control. As soon as the lane is clear or the distance is greater than the limit distance, the motor vehicle is accelerated again to the desired speed by means of the automatic distance control.

By means of the automatic distance control, a distance to the possibly preceding further motor vehicle is automatically maintained during operation and in particular braking interventions are carried out. If, for example, the driver wants to overtake a number of motor vehicles, or otherwise does not want to comply with the minimum distance (limit distance) set by the automatic distance control, the driver can deactivate the automatic distance control. In this case, it is still possible to activate the cruise control system, so that the desired speed is regulated. By means of the method, in particular on the basis of the output of the warning, it is ensured that the driver is aware that no active braking, ie an automatic compliance with the limit distance, takes place. Thus, a security is increased.

For example, in particular in response to a comparatively small distance, that is to say a low limit value, an emergency braking is carried out as a warning. Particularly preferred, however, is omitted such an intervention in the brake system.

The cruise control system is a component of a motor vehicle and in particular has a control unit, by means of which a method is carried out. The control unit is formed for example by means of a microprocessor or includes, for example, this. In particular, the control unit is designed to be programmable or a user-specific circuit (ASIC). The method provides that a speed of the motor vehicle is regulated to a desired speed, and a distance to a preceding further motor vehicle is determined. Then, if the distance is less than a limit, a warning is issued. The control unit is preferably suitable, in particular provided and arranged to perform the method. Preferably, the cruise control system has an interface for a drive control, so that by means of the cruise control system Drive control can be acted upon with appropriate commands. The cruise control system expediently has a camera, a display and / or a loudspeaker. At least, however, the speed control system in each case has an interface for this, so that the warning can be output optically and / or acoustically. For example, one of the above-mentioned interfaces, preferably all interfaces, is provided by means of an interface for a bus system. Thus, hardware requirements are reduced.

The motor vehicle preferably has a number of wheels. By means of the wheels in particular a contact with an environment, suitably a floor, such as a lane. The motor vehicle is land bound and preferably was moved independently of rails or the like. For example, the motor vehicle is a passenger car or a commercial vehicle, such as a truck or bus. In particular, the motor vehicle is suitable, in particular provided and set up to be moved autonomously, in particular automatically.

The motor vehicle has a drive which comprises, for example, an internal combustion engine, an electric motor or a combination thereof. In particular, the drive has a drive control, by means of which a power of the drive is adjusted. The drive is suitably a component of a drive train, by means of which at least a number of wheels are driven during operation.

The motor vehicle includes a cruise control system operated according to a method in which a speed of the motor vehicle is controlled to a desired speed and a distance to a preceding another motor vehicle is determined. Then, if the distance is less than a limit, a warning is issued. The cruise control system expediently comprises a control unit for carrying out the method.

In particular, the motor vehicle has a unit for detecting a driver input, for example a switch, such as a rotary or toggle switch. Depending on the driver input, the speed is regulated to the desired speed. In other words, in particular a signaling connection between the switch and the cruise control system is present. By means of the switch, the desired speed is preferably predetermined. In summary, during operation the drive is regulated as a function of the driver input by means of the speed control system, in particular to the desired speed.

Conveniently, the motor vehicle has a sensor for detecting the further motor vehicle, in particular its distance from the motor vehicle. The sensor is preferably a camera or a radar sensor. The warning is output, for example, by means of a component of the cruise control system, or the warning is fed, for example, in a bus system of the motor vehicle. In particular, the warning is emitted optically by means of a display and / or by means of a loudspeaker.

The advantages and developments described in connection with the method are to be transferred analogously to the cruise control system / motor vehicle and vice versa.

• 1 ein Verfahren zum Betrieb einer Geschwindigkeitsregelanlage eines Kraftfahrzeugs,
• 2 schematisch vereinfacht das Kraftfahrzeug.

An embodiment of the invention will be explained in more detail with reference to a drawing. Show:

• 1 a method for operating a cruise control system of a motor vehicle,
• 2 schematically simplifies the motor vehicle.

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

In 1 is a simplified schematic method 2 for operating a cruise control system 4 shown. The cruise control system 4 is a component of a motor vehicle 6 , this in 2 is shown. The cruise control system 4 includes a control unit 8th , by which at least partially the method 2 is carried out. In addition, the cruise control system 4 an interface to a display 10 and a speaker 12 on that in an interior 14 of the motor vehicle 6 are arranged, in which in operation of the driver of the motor vehicle 6 located.

Furthermore, the cruise control system 4 an interface to a camera 16 on, which serves the traffic sign recognition. In other words, the chamber 16 a component of a traffic sign recognition. In addition, the speed control system includes 6 an interface to a radar sensor 18 as well as the camera 16 in a direction of travel of the motor vehicle 6 are directed. The radar sensor 18 is part of an automatic distance control (ACC).

In addition, the cruise control system 4 via a respective interface with a drive control of a drive 20 and a braking system 22 connected by signal technology. Further, the cruise control system 4 Signaling with a switch 24 signal technically connected, the also in the interior 14 is arranged. The respective interfaces are, for example, dedicated interfaces or particularly preferably each realized by means of a single connection to a bus system that is a CAN bus system.

The procedure 2 provides that in a first step 26 a driver input 28 is detected by means of the switch 24 is created. The driver input 28 corresponds to a desired speed 30 , In particular, the desired speed 30 by means of the display 10 visually displayed, so that the driver his desired speed 30 confirm or correct if necessary.

In a subsequent second step 32 is by means of the control unit 8th the drive control of the drive 20 driven, so a speed 34 of the motor vehicle to the desired speed 30 is adjusted. In other words, the speed 34 to the desired speed 30 regulated. Thus, by means of the cruise control system 4 the actual speed 34 of the motor vehicle 6 with the desired speed 30 compared and depending on this, the control of the drive 20 charged with appropriate commands and the drive 20 thus regulated. In summary, the drive 20 depending on the driver input 28 by means of the cruise control system 4 regulated. Thus, the motor vehicle moves 6 essentially automatically on a lane 36 with the constant desired speed 30 ,

In a third step 38 becomes a preceding vehicle 40 by means of the camera 16 and / or the radar sensor 18 if present, recorded. The preceding motor vehicle 40 is also in the lane 36 and is at a second speed 42 moves that are smaller than the desired speed 30 and thus the speed 34 is. In other words, in the third step 38 to the presence of the preceding further motor vehicle 40 checked. If no preceding motor vehicle 40 is present, becomes the third step 38 while running until the procedure 2 is terminated otherwise, or the preceding further motor vehicle 40 is detected.

If the driving ahead further motor vehicle 40 is recorded in a subsequent fourth step 44 a distance 46 of the motor vehicle 6 to the preceding motor vehicle 40 certainly. The distance 46 is using the camera 16 and / or the radar sensor 18 recorded and thus determined. The distance 46 comes with a limit 48 compared. The limit 48 depends on the speed 34 and especially equal to the value that the motor vehicle 6 covered in a second.

When the distance 46 less than the limit 48 is, is in a fifth step 50 a warning 52 output. This will be the warning 52 optically by means of the display 10 in the interior 14 of the motor vehicle 6 output. For example, a pictogram is used for this purpose. In addition, the warning 52 acoustically by means of the loudspeaker 12 in the interior 14 output, for example as a warning tone. Thus, the driver of the motor vehicle 6 on the preceding motor vehicle 40 both visually and acoustically pointed.

In addition, by means of the control unit 8th the brake system 22 triggered such that a brake pressure is performed. Thus, the brakes of the motor vehicle are briefly 6 operated, in particular only for 0.1 second. Thus, the speed becomes 30 of the motor vehicle 6 not significantly reduced due to the brake pressure. The driver of the motor vehicle 6 in this case, however, haptic is on the preceding vehicle another motor vehicle 40 pointed. In addition, as a warning 52 the regulation to the desired speed 30 completed. In other words, an imposition of the drive 20 terminated with corresponding control commands. Thus, the motor vehicle 6 slowed down, for example due to air resistance or a drag torque, which is why the distance 46 not downsized or a speed of reduction of the distance 46 is reduced.

Unless the driver of the motor vehicle 6 the preceding motor vehicle 40 had not yet registered, for example, because this was distracted or fallen asleep, due to the warning 52 this on the preceding vehicle another motor vehicle 40 made aware. Thus it is for the driver of the motor vehicle 6 possible, the speed 34 of the motor vehicle 6 by operating the brake system 22 decelerate. As a result, a collision is prevented.

If the driver of the vehicle 6 the preceding motor vehicle 40 want to overtake and on an adjacent lane 52 Dodge is due to the procedure 2 a loss of speed of the motor vehicle 6 only comparatively low and comparatively short-term compensated by means of manual operation. Thus, the motor vehicle 6 on the adjacent lane 52 essentially immediately with the desired speed 30 or a greater speed moves, so for the driver of the motor vehicle 6 due to the brake pressure no excessive loss of comfort done. Also, something will be on the adjacent lane 52 approaching additional motor vehicle due to an excessive reduction in speed 34 of the motor vehicle 6 not hindered by this. For example, after the motor vehicle 6 on the adjacent lane 52 was spent and thus in the direction of travel no obstacle, such as a motor vehicle, is again by means of the rule of convenience 4 to the desired speed 30 regulated.

In summary, due to the warning 52 a takeover request for the driver of the motor vehicle 6 , For example, as a warning 52 additionally carried out an emergency braking, which can be terminated in particular by means of a manual operation. Preferably, however, there is no emergency braking. Due to the procedure 2 be at the cruise control system 4 existing information, in particular by means of the camera 16 and the radar sensor 18 is used, without imitating the functionality of an automatic distance control, in which there are relatively high security requirements. Thus, due to the warning 52 a driver information, in particular a takeover request, issued, which in particular by means of the display 10 and the speaker 12 he follows. This is done when the distance 46 less than the limit 48 is. In addition, the brake pressure is preferably output, in particular if the driver of the motor vehicle 6 not on the visual and / or acoustic output of the warning 52 responding.

Due to the procedure 2 Rear-end collisions can be avoided, in particular if the driver of the motor vehicle 6 did not realize that no automatic adjustment of the distance 46 he follows. This will be already existing sensors such as the camera 16 and the radar sensor 18 used, which are used for example in other assistance systems and thus already in the motor vehicle 6 are installed / available.

The invention is not limited to the embodiment described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the exemplary embodiment can also be combined with each other in other ways, without departing from the subject matter of the invention.

LIST OF REFERENCE NUMBERS

2

method

4

Cruise control

6

motor vehicle

8th

control unit

10

display

12

speaker

14

inner space

16

camera

18

radar sensor

20

drive

22

braking system

24

counter

26

first step

28

driver input

30

desired speed

32

second step

34

speed

36

lane

38

third step

40

preceding vehicle

42

second speed

44

fourth step

46

distance

48

limit

50

fifth step

52

adjacent lane

Claims (7)

Method (2) for operating a cruise control system (4) of a motor vehicle (6), in which a speed (34) of the motor vehicle (6) is regulated to a desired speed (30), a distance (46) to a preceding further motor vehicle (40) is determined, and - If the distance (46) is less than a limit (48), a warning (52) is issued. Method (2) according to Claim 1 , characterized in that the warning (52) is issued visually and / or acoustically in an interior (14) of the motor vehicle (6). Method (2) according to Claim 1 or 2 , characterized in that a brake pressure is used as a warning (52). Method (2) according to one of Claims 1 to 3 , characterized in that as a warning (52) the regulation to the desired speed (30) is terminated. Method (2) according to one of Claims 1 to 4 , characterized in that the distance (46) to the preceding further motor vehicle (40) by means of a camera (16) is detected. Cruise control system (4) of a motor vehicle (6), which according to a method (2) according to one of the Claims 1 to 5 is operated. Motor vehicle (6) with a drive (20) and with a cruise control system (4) according to Claim 6 , wherein the drive (20) in response to a driver input (28) by means of the cruise control system (4) is regulated.

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