DE102015226701A1 - Method for controlling the speed of a motor vehicle - Google Patents

Abstract

The invention relates to a method for controlling the speed of a motor vehicle, is checked as a trigger condition for the cruise control, whether a pedal angle of an accelerator pedal of the motor vehicle within a predetermined pedal angle interval (210), and wherein, as long as the trigger condition is met, a speed of the motor vehicle constant is held at a desired speed value (220).

Description

The present invention relates to a method for controlling the speed of a motor vehicle as well as a computer unit and a computer program for its implementation.

State of the art

In the course of a cruise control, the driver of a motor vehicle can select a desired driving speed, for example via a switch in the dashboard area. Special measures are automatically taken to ensure that the desired driving speed is maintained. For example, a fuel supply can be increased or throttled or a brake of the vehicle can be actuated automatically.

The DE 10 2006 053 934 A1 describes a cruise control system, wherein an operating time of a control element or a force with which this control element is operated, is determined. One of several stored speeds is selected depending on the actuation duration or force.

Disclosure of the invention

According to the invention, a method for controlling the speed of a motor vehicle as well as a computing unit and a computer program for carrying it out with the features of the independent patent claims are proposed. Advantageous embodiments are the subject of the dependent claims and the following description.

As part of the method, it is checked as a triggering condition, whether a pedal angle of an accelerator pedal of the motor vehicle within a predetermined pedal angle interval (wherein a lower interval limit is greater than zero). As long as this triggering condition is met, a speed control is performed, wherein a speed of the motor vehicle is kept constant at a target speed value. In particular, a speed limit is thus realized in the course of which the speed of the motor vehicle does not exceed a maximum value (expediently the setpoint speed value).

Under the formulation that the "speed of the motor vehicle is kept constant at a desired speed value" should be understood in this context, in particular, that the speed is maintained exactly at this target speed value or at least substantially at this target speed value. In particular, the speed is controlled to the desired speed value or controlled accordingly. Slight temporary fluctuations about the desired speed value, for example in the course of such a control, in particular within the scope of an accuracy interval of e.g. up to 3% around the desired speed value, should be allowed in particular, without departing from the scope of the invention.

The invention proposes a possibility for the intuitive, simple and user-friendly implementation of a speed control and in particular speed limitation. The speed control is activated or deactivated in particular only by operating the accelerator pedal in relation to the predetermined pedal angle interval. If the pedal angle leaves the pedal angle interval when the cruise control is activated, the cruise control is deactivated in particular. Appropriately, it is not necessary to actuate additional actuators except for the accelerator pedal, such as switches or levers in the dashboard of the motor vehicle for speed control.

A driver is thus not distracted while driving, that he must search for the speed control actuators and actuate in a predetermined manner or that he must set a target speed value explicitly, for which he may have to look long time on the speedometer and / or the dashboard area and have to turn his attention away from the road. Furthermore, no additional hardware and no conversion measures are necessary for carrying out the method. The method can be implemented easily and with little effort in a control unit of the motor vehicle.

The desired speed value may be, for example, a predetermined value or a current speed value of the motor vehicle. For example, before the start of the journey, the driver can specify the setpoint speed value or also a multiplicity of possible setpoint speed values, for example via an on-board computer. Conveniently, it is not necessary for the driver to make inputs during the journey to perform the cruise control.

For example, the desired speed value can also be derived from current traffic information, in particular by means of traffic sign recognition and / or by means of (GPS-based) navigation data. Appropriately, the current speed limit of the section on which the motor vehicle just is moved, are derived as a target speed value.

In particular, the driver need not maintain the pedal angle accurately within a very narrow and accurate frame, as would be the case, for example, with manual speed control by corresponding pedal movement of the driver. With such a manual cruise control even small deviations or variations in the pedal angle can lead to an undesirable change in speed, which is why the manual control is associated with a very poor control quality and possibly high emissions through frequent and rapid switching between positive and negative acceleration. Furthermore, such a manual control can lead to a strong distraction of the driver from the traffic, as he often has to look at the speedometer, which in turn can lead to lack of concentration and fatigue in the long run.

In contrast, the pedal angle interval for the method can be made wide enough so that the speed control is not disabled even with slight variations in the pedal angle within the pedal angle interval, which are normal by natural Fußbewegungen and the speed of the motor vehicle can be kept constant. Also, a distraction of the driver, lack of concentration and fatigue by frequent views of the speedometer can be prevented by the process.

The pedal angle values within the pedal angle interval can, for example, be associated with a drive at constant speed, in particular a constant drive with the setpoint speed value. Thus, when the driver operates the accelerator pedal within the pedal angle interval, it is automatically detected that the driver wants to activate the cruise control and constantly move the vehicle at the target speed. If the pedal angle is outside the pedal angle interval, the cruise control is in particular deactivated and the motor vehicle can be regularly accelerated or decelerated.

For example, if the driver gives a lot of throttle comparatively from a standing position and the pedal angle is therefore outside the pedal angle interval, the motor vehicle is regularly accelerated and the cruise control is not activated.

If the driver reduces the speed or the acceleration and reduces the pedal angle until it lies within the pedal angle interval, the cruise control is expediently activated.

If the cruise control is active and the driver accelerates so that the pedal angle leaves the pedal angle interval, in particular the cruise control is deactivated and the speed is regulated according to the respective current pedal angle. The same applies, in particular, to a slowing down of the vehicle, ie if the driver reduces the pedal angle when the cruise control is activated until it leaves the pedal angle interval. In this case, the cruise control is interrupted and the vehicle decelerates according to the current pedal angle and thus reduces its speed.

Advantageously, the cruise control is deactivated and the speed of the motor vehicle is changed in the course of a regular operation in dependence on the pedal angle when the triggering condition is no longer met. If the pedal angle thus moves out of the pedal angle interval when the cruise control is activated, the cruise control is deactivated and the vehicle can be regularly accelerated or decelerated according to the corresponding current pedal angle.

A lower interval limit of the pedal angle interval preferably corresponds to a pedal angle at which, during normal operation of the motor vehicle without active cruise control, a torque dependent on the pedal angle is generated which keeps the speed of the motor vehicle constant at the desired speed value. Conveniently, therefore, a speed limit can be realized upwards. The lower interval limit expediently represents a dynamic threshold. At pedal angles below this dynamic threshold or below the lower interval limit, therefore, the cruise control is deactivated and in particular generates a torque which is smaller than the torque corresponding to the desired speed value. In normal operation, the vehicle would accelerate especially at pedal angles above the lower interval limit, while with active cruise control, the speed is kept constant at the target speed value.

In the context of the method, a requested torque specified by the driver via the accelerator pedal or via the corresponding pedal angle is, in particular, converted unchanged by the vehicle, i. the vehicle speed is not kept constant when a torque is demanded via the pedal angle which is smaller than the torque corresponding to the target speed value.

In contrast to conventional speed limiters, in which the vehicle speed is optionally regulated, too if the accelerator pedal is not actuated, the vehicle will be decelerated if the accelerator pedal is easily or fully released during cruise control while the procedure is activated. If the driver stops the pedal and thus sets a pedal angle of 0%, the vehicle is delayed accordingly, for example.

Advantageously, the method also allows multiple target speed values to be used and intuitively changed between them while driving, only by operating the accelerator pedal, without operating an additional actuator, and without additional inputs while driving. In this case, if the pedal angle is within the pedal angle interval, the speed of the motor vehicle can be kept at the next higher or the next lower target speed value in the course of the cruise control.

For example, if the speed of the vehicle is approaching near a first, lowest setpoint speed, and the driver depresses the accelerator pedal in the pedal angle interval, the speed of the vehicle will be maintained at that first setpoint speed once it has reached it. If the driver accelerates and moves the accelerator pedal out of the pedal angle interval, the vehicle speed is increased, for example, until it is in the vicinity of a second setpoint speed. If the driver then reduces the pedal angle until it is again in the pedal angle interval, the speed is in particular kept constant at this second set speed once it has reached it. Thus, an appropriate number of target speeds can be defined.

According to an advantageous embodiment, it is checked in each case as an additional trigger condition whether the current speed of the motor vehicle lies within a predetermined speed interval around the target speed and / or if an acceleration of the motor vehicle, which depends in particular on the current pedal angle, within a predetermined Acceleration interval is and / or if there is no actuation of the brake of the motor vehicle. The cruise control is preferably activated and the speed of the motor vehicle is kept constant at the desired speed value when one or more of these tripping conditions are met, preferably when all tripping conditions are met. The cruise control is advantageously deactivated when at least one of these tripping conditions is no longer met.

Thus, the activation or deactivation of the cruise control can be additionally secured and an accidental activation, for example because the driver only accidentally or unconsciously actuates the accelerator pedal in the pedal angle interval, can be excluded. In particular, it can be prevented that the motor vehicle is suddenly controlled to a target speed, which is much higher or much lower than the current vehicle speed, when the pedal angle accidentally moves within the interval Pedalwinkelintervalls. Conveniently, it is ensured that the cruise control is deactivated immediately when the driver operates the brake pedal.

According to a first particularly preferred embodiment, a plurality of desired speed values are predetermined and stored, for example, in a control unit of the motor vehicle. By way of example, these different desired speed values can be stored as standard in the course of a production process of the motor vehicle. In particular, they can be changed by the driver and / or the driver can specify desired speed values.

In this case, it is preferable to check as the triggering conditions whether the pedal angle is within the predetermined pedal angle interval and whether the current speed of the motor vehicle is within a predetermined speed interval around a target speed value of these plurality of target speed values. When these two triggering conditions are met, the speed of the motor vehicle is kept constant at that corresponding desired speed value, around which it is in the respective speed interval, once it has reached it. The driver can thus switch in a user-friendly and intuitive manner between the different target speed values.

For example, a first target speed value of 30 km / h may be stored for low-traffic areas, a second target speed value of 50 km / h for trips within closed towns, a third target speed value of 100 km / h for driving on rural roads and a Fourth and possibly a fifth target speed value of 110 km / h or 130 km / h for highway driving.

According to a second particularly preferred embodiment, a desired acceleration of the motor vehicle is determined from the pedal angle, in particular by means of characteristic diagrams. For pedal angle values within the pedal angle interval, zero acceleration is predetermined.

Conventionally, the current pedal angle can be converted by means of maps mostly in a desired torque, for example, in a desired engine torque or a target wheel torque. By the preferred conversion of the pedal angle into the desired acceleration, the corresponding pedal angle values for which no acceleration is to be generated and for which the motor vehicle is to be moved at a constant speed can be predefined in a simple manner by storing corresponding characteristic maps. The cruise control can thus be activated automatically as soon as the pedal angle is within the pedal angle interval.

Again, a variety of different desired setpoint velocity values can be used. In particular, it is possible to set the respective current speed value in a simple manner as a setpoint speed value by moving the accelerator pedal into the pedal angle interval when the corresponding desired speed is reached.

In order to be able to adjust the current acceleration to the corresponding desired acceleration set by means of the pedal angle, for example, a so-called "closed-loop" control can be carried out or a corresponding "closed-loop" controller can be used. For example, such a "closed-loop" controller may include a pre-regulation and a PID controller.

Preferably, when the pedal angle is within the predetermined pedal angle interval, a speed of the motor vehicle is determined as the desired speed value upon entry of the pedal angle into the pedal angle interval and the speed of the motor vehicle is maintained constant at that desired speed value as long as the pedal angle is within the predetermined pedal angle interval.

Advantageously, it is communicated to the driver of the motor vehicle haptically when the triggering condition is met and / or when the triggering condition is no longer met. For example, it can be notified to the driver haptically when the pedal angle is within the pedal angle interval or leaves. In particular, reaching the lower interval limit and an upper interval limit can be communicated to the driver in a haptic manner. Thus, the driver receives a clear feedback whether the cruise control has been activated or deactivated, in particular without the driver having to look away from the road. Preferably, the haptic feedback is communicated via the accelerator pedal.

Preferably, a vibration of the accelerator pedal is generated when the triggering condition is met, for example when the pedal angle reaches the lower interval limit and / or an upper interval limit of the pedal angle interval. In this case, the vibration can be generated in particular in the event of exceeding or falling below the respective interval limit.

Preferably, a pedal angle-dependent pedal force or a pedal angle-dependent pedal resistance is reduced, in particular abruptly reduced, when the pedal angle exceeds a lower interval limit of the pedal angle interval and / or increases the pedal angle-dependent pedal force, in particular increases abruptly when the pedal angle exceeds an upper interval limit of the pedal angle interval. In particular, for this purpose a corresponding pedal angle-dependent counterforce or a corresponding pedal angle-dependent counter resistance of the accelerator pedal can be actively generated (so-called active accelerator pedal).

The pedal angle-dependent pedal force in this case is to be understood as meaning a force which must be applied in order to maintain the corresponding pedal angle. The pedal force to be applied by the driver expediently changes with the corresponding actively generated opposing force.

Under the fact that the pedal force increases suddenly or suddenly reduced in this context, it should be understood in particular that the applied pedal force increases up to the respective interval limit or runs constantly and after reaching and especially exceeding the corresponding interval limit a clearly perceptible for the driver Jump to a higher or lower value.

Advantageously, when the pedal angle is changed so that it leaves the pedal angle interval, the speed of the motor vehicle is changed with an acceleration that is dependent on a current speed of the motor vehicle and the current pedal angle. Thus, in particular, it is achieved that the motor vehicle can be accelerated or decelerated smoothly and smoothly when the driver deactivates the cruise control. In particular, the acceleration is gradually changed from its initial value to a value defined by the pedal angle.

In particular, for this purpose, a required by the driver by appropriate actuation of the accelerator pedal target torque with a factor that expediently moves between zero and one, be multiplied. This factor is preferably pedal angle-dependent and is in particular with increasing pedal angle larger. The more the driver actuates the gas pedal, the stronger the vehicle is accelerated. Alternatively or additionally, the factor is preferably speed-dependent, with the factor becoming larger as the distance of the current speed from the desired speed value increases.

An arithmetic unit according to the invention, e.g. a control device of a motor vehicle is, in particular programmatically, configured to perform a method according to the invention.

Also, the implementation of the method in the form of a computer program is advantageous because this causes very low costs, especially if an executive controller is still used for other tasks and therefore already exists. Suitable data carriers for providing the computer program are in particular magnetic, optical and electrical memories, such as e.g. Hard drives, flash memory, EEPROMs, DVDs, etc. It is also possible to download a program via computer networks (Internet, intranet, etc.).

Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.

The invention is illustrated schematically by means of embodiments in the drawing and will be described below with reference to the drawing.

Brief description of the drawings

1 schematically shows a motor vehicle, which is adapted to carry out a preferred embodiment of a method according to the invention.

2 schematically shows a preferred embodiment of a method according to the invention as a block diagram.

3 shows schematically diagrams of vehicle sizes plotted against time, which can be determined in the course of a preferred embodiment of a method according to the invention.

4 shows a schematic diagram of a target acceleration plotted against a pedal angle, which can be determined in the course of a preferred embodiment of a method according to the invention.

5 schematically shows a diagram of a pedal force plotted against a pedal angle, which can be determined in the course of a preferred embodiment of a method according to the invention.

Embodiment (s) of the invention

In 1 is a motor vehicle shown schematically and with 100 designated. The motor vehicle has a control unit 110 , In particular, an engine control unit, which is in particular set up programmatically to perform a preferred embodiment of a method according to the invention.

A sensor 120 is intended to provide a pedal angle of an accelerator pedal 130 of the motor vehicle. This detected pedal angle is detected by the sensor 120 to the control unit 110 transmitted, which activates or deactivates a speed control in response to this pedal angle in the course of the preferred embodiment of the method according to the invention.

In 2 the preferred embodiment of the method according to the invention is shown schematically as a block diagram. In one step 210 is from the engine control unit 110 as a trigger condition checks if the pedal angle is within a predetermined pedal angle interval. Conveniently, by the engine control unit 110 In addition, it will be checked whether other triggering conditions are met, such as in relation to 3 is explained.

If the trigger condition (s) is / are met, in step 220 a cruise control activated, in the course of which the engine control unit 110 the speed of the motor vehicle 100 constant at a desired speed value (as soon as it has reached this set speed value, for example).

Suitably, an acceleration or deceleration behavior of the vehicle may already be influenced before the vehicle speed actually reaches the setpoint speed value, in order to enable a smooth, smooth adjustment to the desired speed value and thus a smooth transition between regular operation and cruise control. For this purpose, a corresponding desired torque can be multiplied by a speed and / or pedal angle-dependent factor, as explained below.

In the course of the cruise control, for example, a fuel injection amount may be changed accordingly and / or a brake of the motor vehicle may be operated accordingly to regulate the vehicle speed.

According to step 230 it is checked whether the trigger condition or at least one of the trigger conditions is no longer met. If this is the case, the cruise control will be in step 240 disabled. Then it will be again in step 210 checks whether the trigger condition (s) is / are fulfilled again.

The activation or deactivation of the speed control as a function of the pedal angle can in particular be realized according to two particularly advantageous embodiments, as described below with reference to FIG 3 to 5 is described.

According to a first particularly preferred embodiment, and / or a plurality of desired speed values is given. For example, this plurality is in a manufacturing process of the motor vehicle 100 in the engine control unit 110 deposited and / or can by the driver of the motor vehicle 100 entered or selected or modified before the start of the journey.

This first preferred embodiment is based on 3 described. The 3a to 3c each show a diagram, in each case four curves are shown, each representing the time course of different vehicle sizes. For each of these curves, a corresponding ordinate is shown in each case.

A first turn 311 . 312 respectively. 313 describes in each case the pedal angle α of the accelerator pedal plotted against time. According to the assigned ordinate, the pedal angle α can assume values between 0% and 100%, with the accelerator pedal not being actuated at 0% and being in its rest position and with 100% corresponding to a maximum passage of the accelerator pedal.

A second turn 321 . 322 respectively. 323 each describes the time course of the acceleration a of the vehicle. According to the corresponding acceleration coordinate, the acceleration may, for example, assume values between -2.5 m / s ² and + 2.5 m / s ² .

A third turn 331 . 332 respectively. 333 describes in each case the time course of the speed v of the vehicle plotted against time.

A fourth curve 341 . 342 respectively. 343 indicates whether the cruise control is activated or deactivated. When the cruise control is activated, the corresponding curve is at the value v _reg = 1, with deactivated cruise control the value v _reg = 0.

In this example, two target speed values are specified. A first desired speed _value v _soll1 is, for example, 60 km / h, a second set speed _value v _soll2 is eg 90 km / h.

In this preferred embodiment, it is checked as triggering conditions whether the pedal angle is within a predetermined pedal angle interval between 25% and 50% and whether the current speed of the motor vehicle within a predetermined speed interval of ± 5 km / h by one of the two target speeds v _soll1 or v _{soll2 is} around and whether the acceleration of the motor vehicle within a predetermined acceleration interval of -1 m / s ² to +1 m / s ² and whether there is no actuation of the brake of the motor vehicle. Only when all these conditions are met will the cruise control be activated.

In the example of 3a the cruise control is not activated. The driver wants to accelerate in this example, for example, at a highway ramp from a standstill. At a time t ₁ , the driver presses the gas pedal completely through, whereby the pedal angle α assumes a value of 100%. The engine control unit 110 recognizes on the basis of the high pedal angle that no speed control should be active. The vehicle is accelerated with a comparatively high acceleration and the speed of the vehicle 100 increases beyond both set speed _values v _set1 and v _set2 .

In the example of 3b For example, after a traffic light red phase, the driver wants to accelerate to the permitted speed of 60 km / h.

At a time t ₂ , the driver operates the accelerator pedal at a pedal angle of 45%. Accordingly, the motor vehicle is accelerated with a comparatively high acceleration. At a time t ₃ , the driver begins to reduce the pedal angle. At a time t ₄ all trigger conditions are met. The engine control unit 110 recognizes that the speed control of 60 km / h is desired and activates it. The car 100 is in the course of the engine control unit 110 automatically with the speed of v _soll1 = 60 km / h after the speed has reached this first target speed value, in particular by a previous, pedal angle-dependent reduction of the acceleration expediently smoothly and without jumps in the acceleration behavior. Despite small variations in the pedal angle, the speed remains constant at the first target speed value.

At a time t ₅ , the driver begins to increase the pedal angle again, for example because he is at a local end and the vehicle 100 would like to accelerate to a higher speed. At a time t ₆ , the cruise control is deactivated and the vehicle is accelerated to a value in excess of the first target speed value. In particular, the speed is thereby increased gently and smoothly, and the acceleration behavior of the vehicle increases depending on the pedal angle as the distance to the last valid setpoint speed value of 60 km / h increases. The cruise control rampt accordingly.

In the example of 3c the driver wants the vehicle 100 initially accelerate from a standstill to 60 km / h and operated at a time t _7, the accelerator pedal at an angle of 35%.

At a time t ₈ all trigger conditions are met, the cruise control is activated and the vehicle 100 is from the engine control unit 110 is moved at the first target speed of 60 km / h after the speed has reached this target speed value.

At a time t ₉ , the driver begins to press the accelerator pedal further and to increase the pedal angle because he is the vehicle 100 would like to accelerate at the local end to the permitted speed of 90 km / h. At a time t ₁₀ , the cruise control is deactivated.

At a time t ₁₁ , the driver reduces the pedal angle again. At a time t ₁₂ again all trigger conditions are met, so that the cruise control is activated again. The engine control unit 110 moves the vehicle 100 then with the second target speed of 90 km / h, as soon as this second target speed value is reached.

The activation or deactivation of the cruise control in the above cases is preferably realized as follows:
In particular, the cruise control is not stopped abruptly as soon as the current pedal angle leaves the pedal angle interval. Instead, in the course of the cruise control, the speed of the vehicle is changed at an acceleration which is dependent on the current speed of the motor vehicle and on the current pedal angle. Thus, a smooth, not jerky acceleration is guaranteed out of the respective target speed value out.

In particular, the current speed is increased with an initially low acceleration value, which gradually increases. The cruise control will eventually be disabled.

In particular, a speed difference between the current speed of the motor vehicle and the next higher setpoint speed value is determined. Based on this speed difference, a maximum acceleration and a maximum torque are determined.

When the driver operates the accelerator pedal during active cruise control at pedal angles outside the predetermined pedal angle interval, the corresponding pedal angle is reduced to a desired torque, e.g. converted into a desired engine torque, in particular by means of appropriate maps. The corresponding desired torque dependent on the set pedal angle is multiplied by a factor which can be between zero and one. In particular, this factor determines the acceleration behavior from the respective desired speed value.

This factor depends both on the current pedal angle and on the current vehicle speed. As the pedal angle increases, the factor becomes larger. Even with increasing distance of the current speed to the respective target speed value, the factor also becomes larger.

As soon as the pedal angle increases during the activated cruise control and thus also the corresponding factor, the moment necessary for holding the speed is exceeded and the vehicle accelerates beyond the setpoint speed value. As the distance to the setpoint speed increases, the factor increases.

Preferably, the same principle applies muatis mutandis when reaching a target speed value. The acceleration is expediently reduced gradually the closer the speed comes to the setpoint speed value, so that it is zero when all the triggering conditions are met when a setpoint speed value is reached.

Preferably, it is communicated to the driver haptically when the cruise control is activated and deactivated. The activation of the cruise control is notified haptically, for example by vibrating the accelerator pedal. For this purpose, a vibration of the accelerator pedal is generated at the times t ₄ , t ₈ and t ₁₂ , to which all trigger conditions are met.

Furthermore, deactivating the cruise control is notified, for example, by increasing the pedal force when the current speed exceeds the corresponding desired speed value. For example, the pedal force can be increased in a pedal angle range between 0.5% and 1% around the current pedal angle.

The activation or deactivation of the speed control can also be realized according to a second particularly advantageous embodiment, as described below with reference to FIG 4 and 5 is explained.

According to this second particularly preferred embodiment, the current pedal angle is directly in a desired acceleration of the motor vehicle 100 converted. For this purpose, in the control unit 110 appropriate maps are stored. For the given pedal angle interval, a target acceleration of 0 m / s ^{2 is} specified.

In 4 is the target acceleration a _target plotted against the pedal angle α in a schematic diagram.

For the minimum pedal angle of 0%, in this example a desired acceleration of a _{setpoint 1} = -0.2 m / s ^{2 is} specified. Between the pedal angle of 0% and a pedal angle value α ₁ of, for example, 20%, the target acceleration increases strictly monotonically with the pedal angle α up to the value 0 m / s ² , eg linearly.

The predetermined pedal angle interval extends between the pedal angle value α ₁ and a second pedal angle value α ₂ of, for example, 35%. In this pedal angle interval, the target acceleration is constant at 0 m / s ² .

Between the pedal angle α ₂ and the maximum pedal angle value of 100%, the target acceleration increases again strictly monotonically with the pedal angle α up to a value a _Soll2 = 2 m / s ² , eg linear.

According to this preferred embodiment, only one trigger condition is checked, namely, whether the pedal angle is within the pedal angle interval. If this is the case, the cruise control is activated automatically. The setpoint speed value used here is the current speed of the vehicle or, in other words, the speed when entering the pedal angle interval.

Also according to this preferred embodiment, the driver is advantageously notified haptically when the cruise control is activated and deactivated. For this purpose, the pedal angle-dependent pedal force is changed when the pedal angle exceeds and leaves the pedal angle interval.

In 5 schematically is a diagram of the pedal force F plotted against the pedal angle α.

Curve 510 describes the preferred pedal force curve, which initially increases from the minimum pedal angle of 0% linearly with the pedal angle value. In the vicinity of the pedal angle value α ₁ of 20%, the pedal force decreases.

The driver must therefore apply only a small and only moderately increasing pedal force during acceleration from standstill, from the minimum pedal angle value to a pedal angle value within the pedal angle interval. The transition from regular operation to cruise control is only slightly visible to the driver. Analogously, deactivating the cruise control by reducing the pedal angle to values below α _{1 is} only slightly recognizable.

In the pedal angle interval between α ₁ of 20% and α ₂ of 35%, the pedal force again increases linearly with the pedal angle up to a value of F ₁ . At the upper interval limit α ₂ , the pedal force abruptly increases from the value F ₁ to the value F ₂ .

As soon as the pedal angle reaches the upper interval limit α ₂ , the driver must apply a suddenly higher pedal force in order to further increase the pedal angle and to deactivate the cruise control. Analogously, the driver also clearly notices when he activates the cruise control from regular operation at pedal angles above the upper interval limit α ₂ , since a significant force withdrawal of the driver is necessary for this due to the falling pedal force.

Curve 520 describes for comparison a conventional pedal force curve, according to which the pedal force F increases linearly with the pedal angle α.

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 102006053934 A1 [0003]

Claims (15)

Method for controlling the speed of a motor vehicle ( 100 ), wherein it is checked as a triggering condition for the cruise control whether a pedal angle (α) of an accelerator pedal ( 130 ) of the motor vehicle ( 100 ) within a predetermined pedal angle interval ( 210 ), and wherein, as long as the trigger condition is met, a speed of the motor vehicle ( 100 ) is kept constant at a desired speed _value (v _Soll1 , v _Soll2 ) ( 220 ). Method according to claim 1, wherein the cruise control is deactivated and the speed of the motor vehicle ( 100 ) is changed in the course of a regular operation depending on the pedal angle when the trigger condition is no longer satisfied. Method according to claim 1 or 2, wherein a lower interval limit of the pedal angle interval corresponds to a pedal angle at which in the regular operation of the motor vehicle without active cruise control a pedal angle-dependent torque is generated which determines the speed of the motor vehicle ( 100 ) keeps constant at the target speed _value (v _Soll1 , v _Soll2 ). Method according to one of the preceding claims, wherein is checked in each case as an additional trigger condition for the cruise control, whether the current speed of the motor vehicle ( 100 ) is within a predetermined speed _interval around the target speed _value (v _Soll1 , v _Soll2 ) around and / or if an acceleration of the motor vehicle within a predetermined acceleration _interval and / or if no actuation of the brake of the motor vehicle ( 100 ), and wherein the speed of the motor vehicle is only kept constant at the desired speed _value (v _Soll1 , v _Soll2 ) as long as one or more of these triggering conditions are met, in particular as long as all these triggering conditions are met. Method according to one of the preceding claims, wherein a plurality of desired speed _values (v _Soll1 , v _Soll2 ) is predetermined, being checked as triggering conditions, whether the pedal angle (α) is within the predetermined pedal _{angle interval} and whether the current speed of the motor vehicle within a predetermined speed interval around a target speed _value (v _Soll1 , v _Soll2 ) of these plurality of target speed _values , and wherein the speed of the motor vehicle constant on this target speed _value (v _Soll1 , v _Soll2 ) of the plurality of target speed _values held as long as these triggering conditions are met. Method according to one of the preceding claims, wherein from the pedal angle (α) a desired acceleration (a _desired ) of the motor vehicle ( 100 ) and wherein for pedal angle values (α) within the pedal angle interval a zero acceleration is predetermined. Method according to one of the preceding claims, wherein a speed of the motor vehicle when entering the pedal angle in the pedal _{angle interval} as a target speed _value (v _Soll1 , v _Soll2 ) is determined and wherein the speed of the motor vehicle constant at this target speed _value (v _Soll1 , v _Soll2 ) as long as the pedal angle (α) is within the predetermined pedal angle interval. Method according to one of the preceding claims, wherein the driver is haptically informed when the triggering condition is met and / or when the triggering condition is no longer met. Method according to claim 8, wherein a vibration of the accelerator pedal ( 130 ) is generated when the triggering condition is met. Method according to claim 8 or 9, wherein a pedal angle-dependent pedal force (F) is reduced, in particular abruptly reduced, when the pedal angle (α) exceeds a lower interval limit (α ₁ ) of the pedal angle interval and / or the pedal angle-dependent pedal force (F) increases, in particular increased abruptly when the pedal angle (α) exceeds an upper interval limit (α ₂ ) of the pedal angle interval. Method according to one of the preceding claims, wherein, when the pedal angle (α) is changed such that it leaves the pedal angle interval, the speed of the motor vehicle ( 100 ) is changed with an acceleration which depends on the current speed of the motor vehicle ( 100 ) and from the current pedal angle. The method of claim wherein the acceleration is gradually changed to an acceleration corresponding to the current pedal angle (α). Arithmetic unit ( 110 ), which is adapted to perform a method according to any one of the preceding claims. Computer program comprising a computing unit ( 110 ) to perform a method according to any one of claims 1 to 12, when it on the computing unit ( 110 ) is performed. A machine-readable storage medium having a computer program stored thereon according to claim 14.

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