Procedures for operating a motor vehicle and motor vehicle

Abstract

Method for operating a motor vehicle (10) with a distance sensor (12) and a brake assist (14) which keeps the motor vehicle (10) in its current position when the vehicle is stationary, comprising the following steps: - Determining a distance to another motor vehicle (20) located in front of (18) the motor vehicle (10), - Preventing the transmission of a driving command issued by the driver by an accelerator pedal (16) of the motor vehicle (10) as long as the distance to the other motor vehicle (20) located in front (18) of the motor vehicle (10) remains constant, wherein - when an unintentional driving signal is detected, a forward movement of the motor vehicle (10) is prevented, whereby - an unintentional actuation of the accelerator pedal (16) is detected, and in the event of an unintentional actuation of the accelerator pedal (16) no driving signal is transmitted to an engine control unit (36) of the motor vehicle (10), and wherein - a driver motion detection system (26) with a camera (28) directed towards the interior (40) of the motor vehicle (10) detects a movement of the driver and an unintentional actuation of the accelerator pedal (16) is detected from the movement of the driver.

Description

[0001] The invention relates to a method for operating a motor vehicle with a driver assistance system and to a motor vehicle with such a driver assistance system according to the preamble of the independent patent claims.

[0002] Motor vehicles equipped with an automatic stopping and / or starting system are known from the prior art. Such a system typically comprises a long-range distance sensor, such as a laser sensor or a radar sensor, and a short-range distance sensor, particularly an ultrasonic sensor. Depending on the distance from a preceding vehicle measured by the long-range sensor, the system intervenes in the longitudinal guidance of a motor vehicle and maintains a constant distance to the preceding vehicle.

[0003] Furthermore, assistance systems designed to prevent a motor vehicle from rolling away on an uphill or downhill gradient are known in the art. Such an assistance system is also known as an auto-hold function. In vehicles with an auto-hold function, the last applied brake pressure is stored after the vehicle has come to a standstill or increased accordingly by a hydraulic unit of an electronic stability program to prevent the vehicle from rolling away. This allows the driver to lift their foot off the brake pedal, which increases comfort. Pressing the accelerator pedal releases the brake, allowing the vehicle to move off without any problems.

[0004] Accidental or careless application of the accelerator pedal during the Auto Hold function may cause the vehicle to roll, creating a risk of collision with the vehicle ahead. Furthermore, inadvertent and unintentional application of the brakes may result in a stop sign or red light being passed, creating a dangerous traffic situation.

[0005] DE 10 2007 036 787 A1 discloses a motor vehicle with a distance control system and an automatic stopping function. The distance to the vehicle ahead is controlled via a long-range sensor at higher speeds and via a short-range sensor, in particular an ultrasonic sensor, at lower speeds.

[0006] DE 10 2007 039 377 A1 discloses a method for the automatic longitudinal guidance of a motor vehicle with a stop-and-go function. Information regarding the vehicle in front is recorded. This allows the vehicle to be braked to a standstill. If the vehicle in front moves forward again, the vehicle starts moving again and follows the vehicle in front. The area in front of the vehicle is continuously monitored to avoid a collision.

[0007] DE 10 2009 034 963 A1 discloses a method for operating a motor vehicle with a longitudinal guidance system comprising long-range sensors and short-range sensors. The sensor system allows the motor vehicle to follow a vehicle ahead. If an obstacle is detected in the area in front of the vehicle during acceleration, the acceleration is reduced in longitudinal dynamics compared to an obstacle-free acceleration.

[0008] DE 103 20 722 A1 discloses an adaptive cruise control system for a motor vehicle with a sensor device for measuring operating parameters of the vehicle and for measuring the distance to a target object in front of the vehicle. A control device for controlling the speed or acceleration of the vehicle depending on the measured operating parameters and distance data is configured to trigger a stop function for automatically braking the vehicle to a standstill. The vehicle is held at a standstill by automatic braking and can only move off again upon a driver command.

[0009] From EP 1 695 859 A1 an adaptive distance control system for a motor vehicle is known in which the vehicle is prevented from rolling away due to an unintentional actuation of an accelerator pedal or an unintentional release of the brake pedal.

[0010] DE 10 2017 110 307 A1 discloses a method for preventing an unintentional starting of an automatic vehicle, wherein a driver's field of vision is monitored when the automatic vehicle is at a standstill, wherein it is detected whether the driver is directing his attention to a front driving area of ​​the automatic vehicle and wherein - if it is detected that the driver is not directing his attention to the front driving area of ​​the automatic vehicle and in doing so releases the brake actuating element of the automatic vehicle - a brake is activated in such a way that the automatic vehicle does not roll or only rolls slightly from a standstill and the automatic vehicle is prevented from automatically starting and / or is brought back to a standstill.

[0011] However, the disadvantage of the system known from the state of the art is that longitudinal guidance systems are generally not switched on in city traffic and incorrect operation of the accelerator pedal, particularly as a result of inattention, can lead to a rear-end collision.

[0012] The invention is based on the object of preventing a motor vehicle with a driver assistance system, in particular with an auto-hold function, from starting or rolling away if the driver inadvertently touches the accelerator pedal.

[0013] According to the invention, this object is achieved by a method for operating a motor vehicle with a distance sensor, in particular a short-range distance sensor, particularly preferably a radar sensor or ultrasonic sensor, and a brake assistant, in particular a brake assistant with an auto-hold function, which holds the motor vehicle in its current position when the vehicle is stationary. The method comprises the following steps: - Determining the distance to another motor vehicle in front of the motor vehicle, - Preventing the transmission of a driving command given by the driver through an accelerator pedal of the motor vehicle as long as the distance to the other motor vehicle in front of the motor vehicle remains constant, whereby - if an unintended driving signal is detected, forward movement of the motor vehicle is prevented.

[0014] Such a procedure can prevent collisions and dangerous operating conditions of the motor vehicle when the vehicle is stationary and secured against rolling away by the Auto-Hold function. This prevents an inadvertent touch of the accelerator pedal from causing the vehicle to roll forward, thus avoiding rear-end collisions.

[0015] The features mentioned in the dependent claims enable advantageous improvements and non-trivial further developments of the method for operating a motor vehicle specified in independent claim 1.

[0016] In a preferred embodiment of the invention, the distance between the motor vehicle and the other motor vehicle in front of the motor vehicle is determined by a radar sensor or an ultrasonic sensor. A radar or ultrasonic sensor allows the distance to be determined particularly easily and precisely in close range. This allows a defined safety distance to the motor vehicle ahead to be maintained.

[0017] According to the invention, an unintentional actuation of the accelerator pedal is detected, and in the event of an unintentional actuation of the accelerator pedal, no driving signal is transmitted to the motor vehicle's engine control unit. Thus, the vehicle remains idling as long as the area in front of the vehicle is not clear and the distance to the other vehicle does not increase. Alternatively, it would also be possible to separate the drive train from the drive engine, whereby a transmission would lead to an increase in the engine's speed, but no drive torque would be transmitted to the vehicle's wheels.

[0018] In an advantageous embodiment of the method, unintentional actuation of the accelerator pedal is detected by comparing the pressure on the accelerator pedal with the pressure on the accelerator pedal normally applied when starting off. For this purpose, the pedal force exerted on the accelerator pedal is determined. If the driver is mistaken and inadvertently presses the accelerator pedal instead of the brake (as intended), the driver will generally exert significantly greater pedal pressure than during an intended start. Thus, based on the pressure and the length of time the pressure is applied to the accelerator pedal, it can be determined whether the signal was issued intentionally or whether the accelerator pedal was actuated unintentionally. Likewise, unintentional grazing of the accelerator pedal is detected as an unintentional actuation.

[0019] Alternatively or additionally, it is advantageous to detect an unintentional actuation of the accelerator pedal by comparing the accelerator pedal movement with a pedal movement typically used for starting off. If the brake and accelerator are confused, an unintentional actuation generally results in the accelerator pedal being fully depressed. Even an accidental brushing of the accelerator pedal or an unintentional touch differ from a deliberate starting off in terms of the pedal travel and the time course of the pedal travel.

[0020] According to the invention, a driver movement detection system with a camera directed toward the interior of the motor vehicle detects the driver's movement and, based on the driver's movement, detects an unintentional actuation of the accelerator pedal. For example, a camera can be used to detect the driver's eye movement. This can detect, for example, when the driver turns toward passengers in the rear seats and / or averts their gaze from the area in front of the vehicle, for example, to eat or drink something.

[0021] In an advantageous embodiment of the method, a blockage in the signal transmission from the accelerator pedal to the engine control unit is only overcome if the driver actively activates a switching element to deactivate the Auto-Hold function. If the driver wishes to move the vehicle, particularly to form an emergency lane, it may be necessary to reduce the minimum distance to the other vehicle in advance. This requires an active action to deactivate the Auto-Hold function. This can be done, in particular, via a button, switch, or touchpad.

[0022] In a preferred embodiment of the method, it is provided that the accelerator pedal is designed as an electric accelerator pedal and there is no mechanical connection between the accelerator pedal and an actuator for controlling an internal combustion engine of the motor vehicle, in particular a throttle valve.

[0023] According to the invention, a motor vehicle with a distance sensor and a brake assist system that holds the motor vehicle in its current position when the vehicle is stationary is proposed. The motor vehicle has at least one control unit that is configured to carry out a method according to the invention for operating a motor vehicle when a machine-readable program code is executed by the control unit. Such a motor vehicle can further increase general road safety. Although rear-end collisions when starting off do not generally result in serious injuries, material damage to the motor vehicle and the vehicle in front can be avoided. Furthermore, traffic jams resulting from such rear-end collisions can be avoided, which benefits the general public.

[0024] In a preferred embodiment of the motor vehicle, the motor vehicle comprises a first control unit for a longitudinal guidance function and a second control unit, in particular an engine control unit, wherein a signal from the first control unit is given greater weight than a signal from the second control unit. The control unit for the longitudinal guidance function has priority, so that a signal from the accelerator pedal to the engine control unit is inhibited if the area around the motor vehicle is not clear.

[0025] It is particularly preferred if a third control unit is provided for controlling the brakes of the motor vehicle, wherein the first control unit prevents the brakes from being released if the first control unit signals that the area in front of the motor vehicle is not clear.

[0026] The various embodiments of the invention mentioned in this application can be advantageously combined with one another, unless otherwise stated in the individual case.

[0027] The invention is explained below in exemplary embodiments with reference to the accompanying drawings. They show: Fig. 1 a motor vehicle according to the invention with a distance sensor and a brake assistant with auto-hold function, Fig. 2 a flow chart for carrying out a method according to the invention for operating a motor vehicle with a distance sensor and a brake assistant, which reliably and safely prevents a collision caused by an unintentional actuation of an accelerator pedal, and Fig. 3 a representation of the networking of the sensors, the accelerator pedal, the brakes and the control units in a motor vehicle for carrying out a method according to the invention.

[0028] Fig. 1 shows a traffic situation in which a motor vehicle 10 is parked behind another motor vehicle 20 in stop-and-go traffic, for example in city traffic. The motor vehicle 10 has a distance sensor 12, in particular a radar sensor 22 or an ultrasonic sensor, with which the immediate area 18 in front of the motor vehicle 10 is monitored. The motor vehicle 10 further has a brake assist system 14 with an auto-hold function, which holds the motor vehicle 10 in its current position when stationary and prevents the motor vehicle 10 from rolling away. The motor vehicle has an accelerator pedal 16, with which a driving command can be transmitted to a control unit 24, 36, in particular to an engine control unit 36 ​​of an internal combustion engine 42.The motor vehicle is equipped with a distance assistant, which, via the distance sensor 12 and a control unit 24, maintains the distance to the motor vehicle 20 in front at a constant level or does not fall below a minimum distance from the motor vehicle in front. The motor vehicle 10 has an interior 40 in which a driver of the motor vehicle and possibly other passengers can be transported. The motor vehicle 10 has a driver movement detection system 26 with at least one camera 28, via which a movement of the driver can be detected.

[0029] Brakes 44 are arranged on the motor vehicle, which can be subjected to braking pressure by a hydraulic unit. A brake control unit 38 is provided for this purpose, via which the pressure to the wheel brake cylinder of the motor vehicle 10 can be regulated. A control unit 30 is provided in the motor vehicle, which includes a switching element 32 with which the auto-hold function can be activated and deactivated. Alternatively or in addition to the switching element 32, the motor vehicle 10 can have a screen 34 with a touch display, which can replace a switching element 32 and map the function of a switching element 32.

[0030] The control units 24, 36, 38 are interconnected in such a way that, when the motor vehicle 10 is stationary, the brake pressure is maintained or further increased by a hydraulic unit of an electronic stability program to prevent the motor vehicle 10 from rolling away. The area in front of the motor vehicle 10 is monitored to prevent unintentional starting and a resulting collision.

[0031] In Fig. 2 shows the sequence of a method according to the invention for operating a motor vehicle 10. In a first method step <100> the motor vehicle 10 is braked to a standstill. For this purpose, hydraulic pressure is built up in a master brake cylinder and transmitted to the wheel brake cylinders, which apply the brakes 44 on the wheels of the motor vehicle. In one process step <110> This pressure is maintained even when the brake pedal is released or amplified by a hydraulic unit of the brake system in order to prevent the motor vehicle 10 from rolling away. In a method step <120> the area in front of the motor vehicle 18 is detected by a distance sensor 12, in particular by a short-range sensor. In a method step <130> it is checked whether the accelerator pedal 16 of the motor vehicle 10 was actuated intentionally or unintentionally.In case of an unintentional actuation of the accelerator pedal 16, the motor vehicle 10 remains in a process step <160> in its position. The distance to the other motor vehicle 20 is kept constant. If the other motor vehicle 20 is stationary, this prevents the brake pressure from being released upon inadvertent contact with the accelerator pedal 16, and prevents the motor vehicle 10 from moving forward until a deliberate driving command is given.

[0032] If a conscious driving command is given, a procedural step <140> checks whether another motor vehicle 20 is located in the apron 18 of the motor vehicle 10. If the apron 18 of the motor vehicle 20 is clear or if the distance to another motor vehicle 20 increases, the motor vehicle 10 can be moved forward by the drive command.

[0033] A forward movement is achieved in a process step <150> only permitted when the other motor vehicle 20 moves forward and the distance between the other motor vehicle 10 and the other motor vehicle 10 increases. If the other vehicle is stationary, forward movement is initially blocked. This blocking can be carried out in one process step <145> be canceled by actively canceling or deactivating the Auto-Hold function by actuating a switching element 32. This may be necessary, for example, to form an emergency lane in an unexpected traffic jam. After the block has been canceled, in a process step <150> a forward movement of the motor vehicle 10 is possible.

[0034] In Fig.Figure 3 illustrates the interaction of sensors 12, 22 of the various control units 24, 36, 38 and the functional components 16, 30, 32, 44 of motor vehicle 10. Engine control unit 36 ​​detects a standstill of motor vehicle 10 and reports this to control unit 24 for a distance assistant. The distance assistant includes a distance sensor 12, in particular a radar sensor 22, to detect the distance to the preceding motor vehicle 20. Accelerator pedal 16 is designed as an electronic accelerator pedal and has no mechanical coupling to an actuating element, in particular a throttle valve of an internal combustion engine 42. Thus, accelerator pedal 16 can be completely decoupled from internal combustion engine 10. This makes it possible to ignore a driving command via accelerator pedal 16. The driving signal transmitted via the accelerator pedal 16 is ignored in particular if an unintentional actuation of the accelerator pedal 16 is detected.

[0035] The motor vehicle 10 further comprises a brake assist system 14 with an auto-hold function. A hydraulic unit of an electronic stability program is used to increase the pressure in the brake circuits of the motor vehicle 10 if the brake pressure applied to the wheel brakes 44 is not sufficiently high to prevent the motor vehicle 10 from rolling away from its current position. The brake assist system 14 further comprises a control unit 30, in particular a switching element 32 in the form of a button or a lever, via which the brake assist system 14 can be deactivated and / or the auto-hold function can be switched off.

Claims

[1] Method for operating a motor vehicle (10) with a distance sensor (12) and a brake assistant (14) which holds the motor vehicle (10) in the current position when the vehicle is stationary, comprising the following steps: - determining a distance to another motor vehicle (20) located in front (18) of the motor vehicle (10), - preventing the transmission of a driving command issued by the driver by means of an accelerator pedal (16) of the motor vehicle (10) as long as the distance to the other motor vehicle (20) located in front (18) of the motor vehicle (10) remains constant, wherein - upon detection of an unintentional driving signal, a forward movement of the motor vehicle (10) is prevented, wherein - an unintentional actuation of the accelerator pedal (16) is detected, and in the event of an unintentional actuation of the accelerator pedal (16), no driving signal is transmitted to an engine control unit (36) of the motor vehicle (10), and wherein - a driver movement detection system (26) with a camera (28) directed towards the interior (40) of the motor vehicle (10) detects a movement of the driver and an unintentional actuation of the accelerator pedal (16) is detected from the driver's movement. [2] Method according to claim 1, characterized by that the distance between the motor vehicle (10) and the other motor vehicle (20) in front (18) of the motor vehicle (10) is determined by a radar sensor (22). [3] Method according to claim 1 or 2, characterized by that an unintentional actuation of the accelerator pedal (16) is detected by comparing the pressure on the accelerator pedal (16) and a pressure on the accelerator pedal (16) that is usual for starting off. [4] Method according to one of claims 1 to 3, characterized by that an unintentional actuation of the accelerator pedal (16) is detected by comparing the pedal movement of the accelerator pedal (16) and a pedal movement of the accelerator pedal (16) which is usual for starting off. [5] Method according to one of claims 1 to 4, characterized by that a blockage of the signal transmission from the accelerator pedal (16) to the engine control unit (36) is only overcome if the driver actively actuates a switching element (32) to switch off the auto-hold function. [6] Method according to one of claims 1 to 5, characterized by that the accelerator pedal (16) is designed as an electric accelerator pedal and there is no mechanical connection between the accelerator pedal (16) and an actuator for controlling the internal combustion engine (42). [7] Motor vehicle (10) with a distance sensor (12) and a brake assistant (14), which holds the motor vehicle (10) in the current position when the vehicle is stationary, and with at least one control unit (24, 36, 38) which is designed to carry out a method according to one of claims 1 to 6 when a machine-readable program code is executed by the at least one control unit (24, 36, 38). [8] Motor vehicle (10) according to claim 7, characterized by that the motor vehicle (10) has a first control unit (24) for a longitudinal guidance function and a second control unit (36), in particular an engine control unit (36), wherein a signal of the first control unit (24) is weighted more heavily than a signal of the second control unit (36).

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