WO2017084977A1

WO2017084977A1 - Changing thrust recuperation in a motor vehicle with at least one electric machine

Info

Publication number: WO2017084977A1
Application number: PCT/EP2016/077436
Authority: WO
Inventors: Alexander Recknagel
Original assignee: Bayerische Motoren Werke Aktiengesellschaft
Priority date: 2015-11-20
Filing date: 2016-11-11
Publication date: 2017-05-26
Also published as: DE102015223006A1

Abstract

The invention relates to a method for changing thrust recuperation during coasting in a motor vehicle having at least one electric machine that can be used for recuperation. The vehicle comprises a brake pedal that can be actuated by the driver to decelerate the vehicle. According to the invention, an actuation of the brake pedal during downhill driving is detected. The method initially involves operating the vehicle in a recuperation mode with a low level of recuperation in comparison with a level after subsequent mode switching. On detection of actuation of the brake pedal during downhill driving, the system switches to a recuperation mode with increased thrust recuperation. When the brake pedal is released, the increased level of thrust recuperation is effective during coasting.

Description

Changing a Schubrekuperation a motor vehicle with at least one electric machine

The invention relates to a method for changing an effective in overrun Schubrückkuperation a motor vehicle with at least one usable for recuperation electric machine, which is for example part of an electric drive.

In motor vehicles with an electric machine that can be used for recuperation, in particular in vehicles with an electric drive, kinetic energy of the motor vehicle can be converted into electrical energy during regenerative operation of an electrical machine and fed into an electrical energy store (typically a battery or a capacitor). This transformation of the kinetic energy of the motor vehicle into electrical energy is also known as (electrical)

Recuperation called. For recuperation is typically at the set a recuperation, which counteracts the movement of the motor vehicle and this delays.

The recuperation means of the electric drive can be used even when the brake pedal to decelerate the motor vehicle. In the so-called Bremsrekuperation a Rekuperationsmoment or a recuperation power is set upon actuation of the brake pedal, generally dependent on a brake pedal travel, with which the

Brake pedal of the vehicle is depressed by a driver.

Furthermore, the recuperation can also be used in overrun to decelerate the vehicle. In this case, a Schubrekuperationsmoment (also called Schlepprekuperationsmoment) of the vehicle is set at the end of the operation of the accelerator pedal or even before the end of the operation of the accelerator pedal, whereby the motor vehicle is decelerated.

It can be provided that not only at the complete termination of the operation of the accelerator pedal, but already on withdrawal of the operation of the accelerator pedal and even less accelerator pedal operation

Schubrekuperationsmoment is set; the amount of Schubrekuperationsmoments generally decreases with decreasing

Accelerator pedal operation and reaches at the end of the operation of the accelerator pedal its maximum value. By canceling the operation of the accelerator pedal so the vehicle can be dosed delayed.

The recuperation in overrun is also referred to as Schubrekuperation. In Schubrekuperation so is a predetermined

Rekuperationsmoment or a predetermined Rekuperationsleistung set when the driver stops the accelerator pedal of the vehicle (or only slightly). From the prior art it is known, the Schubrekuperationsmoment depending on a selected by the driver via a button

Adapt driving mode from a plurality of driving modes influencing the driving dynamics (for example Eco, Comfort, Sport). For example, in Eco mode, a lower Schubrekuperation is set in overrun compared to the driving modes Comfort and Sport, d. H . the

Delay effect is lower in Eco mode under otherwise identical conditions than in Comfort and Sport mode. In Comfort mode, in turn, less Schubrekuperation, i. a lower amount of Schubrekuperationsmoment than in Sport mode set.

From the document DE 10 201 1 108 446 A1 discloses a method for

Setting the Schubrekuperation of a motor vehicle with electric drive known. Here, a slope of a road on which the vehicle is traveling, automatically detected. It will be a recuperation of the

Vehicle depending on the detected gradient set. For example, depending on the detected gradient, the recuperation power is set such that the vehicle almost maintains or only slightly increases its speed. The Schubrekuperation is set automatically as soon as the driver stops the accelerator pedal. The driver can optionally influence the recuperation power via shift paddles on the steering wheel or an electronic lane on the selector lever and thus change the recuperation performance. In the publication DE 10 2009 036 047 A1 is a method

for controlling a hybrid drive, in which inclination data of a road traveled by the vehicle are determined and the hybrid drive is controlled in dependence on the determined inclination data. The document DE 10 2009 027 553 A1 describes a method for operating a recuperation device of a motor vehicle, which is used to convert a kinetic energy of the motor vehicle into an electric motor Energy is provided. The recuperation device is operated as a function of information provided by a navigation system of the motor vehicle. The document DE 10 2013 221 979 A1 describes a method for decelerating a vehicle with an electric drive. After completion of the operation of an accelerator pedal, a Schubrekuperationsmoment is set. After actuation of the brake pedal, the deceleration of the motor vehicle is increased. With the withdrawal of the operation of the brake pedal, the deceleration of the motor vehicle is reduced, the amount of the set Schubrekuperationsmoments is reduced starting from the non-actuation of the accelerator pedal associated Schubrekuperationsmoments.

Unless on a downhill a vehicle at a set

Schubrekuperation with low deceleration effect in overrun from the driver's point of view by the downhill power too accelerated, the driver must always or constantly press the brake pedal in many cases. As a result, the excessive acceleration of the vehicle can be reduced, for example, to only a slight positive

Acceleration, an acceleration of about zero or a negative acceleration. The acceleration of the vehicle and its

Speed can be kept in a comfortable area for him from the perspective of the driver. The repeated operation of the brake pedal or the continuous operation of the brake pedal are not comfortable for the driver and disturb the driving experience. Unless the

Brake effect on actuation of the brake pedal partially (with simultaneous recuperation) or completely (without recuperation) by a mechanical braking system (eg., A hydraulic disc brake system) is generated, kinetic energy of the vehicle is converted into heat energy (for example in the brake discs) and stands The vehicle then no longer available to drive the vehicle. This will be the

Energy efficiency of the vehicle reduced. In addition, the lead Braking the mechanical brake system to wear, for example on the brake discs or on the tires.

Unless on a downhill at one set to the high

Schubrekuperation the deceleration effect of Schubrekuperation in overrun from the driver's point of view is too high, the driver must repeatedly press the accelerator pedal to counteract the excessive delay effect in overrun. The driving behavior is thus

disharmonious. In addition, from the perspective of the driver is too high

Schubrekuperation and the resulting operation of the accelerator pedal energetically inefficient, since when converting mechanical

Drive energy into electrical energy in overrun mode and in the

Converting electrical energy into mechanical drive energy upon actuation of the accelerator pedal respectively energy losses occur. It is significantly more efficient to maintain the mechanical energy rather than multiple times

convert.

If an adjustment of the recuperation takes place automatically, for example due to measured or retrieved from the navigation system information about the current gradient, this deceleration effect from the driver's point of view may be too high or too low, since this is not adapted to the driver. For example, if the deceleration effect is too high, following an undesired deceleration caused by an automatic increase in recuperation, a speed desired by the driver must first be restored by accelerating the vehicle. For example, when driving downhill, the driver, the vehicle in overrun acceleration through the

Would like to exploit downgrade power, however, the vehicle through

automatic increase in recuperation does not allow this, then the driver must press the accelerator pedal. The automatic adjustment of Schubrekuperation due to retrieved from the navigation system information about the current gradient is often not reliable because the information is often incomplete or even faulty.

If it is a hybrid vehicle with at least one electric drive machine and an internal combustion engine, the driver, unlike a vehicle with purely internal combustion engine drive, the delay effect can not be adjusted by adjusting the engaged gear of the engine brake acting as the internal combustion engine at the downhill is often disconnected.

It is an object of the invention to provide an improved method for adjusting the recuperation in a motor vehicle in view of the disadvantages described above.

The object is solved by the features of the independent claims. Advantageous embodiments are described in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim without the features of the independent claim or only in

Combination with a subset of the characteristics of the independent

Claim can form its own and independent of the combination of all features of the independent claim invention, the subject of an independent claim, a

Divisional application or a subsequent application can be made. This equally applies to technical teachings described in the specification which may form an invention independent of the features of the independent claims. A first aspect of the invention relates to a method for changing an effective thrust operation Schubrekuperation (also known as Schlepprekuperation) of a motor vehicle (for example, motor vehicles, especially passenger cars) with at least one usable for recuperation electric machine. The at least one electric machine can preferably be used not only for recuperation, but also for driving and is therefore preferably part of an electric drive, for example a purely electric vehicle or a hybrid vehicle with electric drive and internal combustion engine. It is also possible to use several electric machines for recuperation in overrun mode, which are part of an electric drive, for example.

The vehicle comprises a driver-actuated brake pedal for decelerating the vehicle, and preferably also an accelerator pedal for accelerating the vehicle.

According to the method, an operation of the brake pedal during a downhill run (i.e., a downhill ride) is detected. Preferably, the presence of a downhill run is also checked. For example, there must be a certain gradient for downhill skiing.

The method initially starts from an operation of the vehicle in a recuperation mode with a lower Schubrekuperation compared to later switching.

In response to the detection of an operation of the brake pedal during the downhill, switching to a recuperation mode with increased Schubrekuperation. After terminating an operation of the

Brake pedal is in overrun the increased Schubrekuperation effective; but the increase in Schubrekuperation can also be effective before when the brake pedal. The Schubrekuperation is then preferably permanently effective, especially until the driver Accelerator pedal pressed again. However, the Schubrekuperation can also be effective already during the operation of the brake pedal and then continue to be effective after completion of the operation of the brake pedal. The method according to the invention makes it possible to adapt the Schubrekuperation to the deceleration request of the driver. Based on the operation of the brake pedal can be detected when the driver feels the currently set Schubrekuperation as too low, so that in response, the Schubrekuperation can be increased. Since the driver can usually increase the deceleration of the vehicle via the operation of the brake pedal, the operation of the brake pedal is evaluated to recognize the driver's desire for increased delay effect and implement accordingly. The driver can thus intuitively increase the Schubrekuperation by pressing the brake pedal.

With the method, after one or more specific conditions, the Schubrekuperation can be increased situational and intuitive for the driver. The Schubrekuperation is not flat rate increased downhill, as such behavior is not expected by the driver. Instead, the increase in Schubrekuperation occurs on driver request. Generally, the increase in vehicle deceleration is intuitively controlled by the driver via the brake pedal; therefore, the increase in Schubrekuperation also occurs in response to actuation of the brake pedal (for example, when the brake pedal is pressed once or is pressed several times during a certain time interval).

The inventive method allows a more pleasant for the driver feel and comfort, since the driver is relieved in a downhill after switching from the operation of the brake pedal and also in contrast to the situation with too high

Schubrekuperation does not have to press the accelerator pedal. For the inventive method is not mandatory

Gradient information about the route necessary, which is retrieved for example from a navigation system to adjust the recuperation situational. The driver can by pressing the brake pedal the

To control Schubrekuperation independently according to his own desire.

Since the driver can adjust the Schubrekuperation when needed, it is avoided that the driver, in contrast to a too low set Schubrekuperation the brake pedal must be frequently or permanently operated and unlike too high set Schubrekuperation must operate the accelerator pedal. This will increase the energy efficiency of the

Vehicle increased. In the case of a vehicle with electric drive so the electrical range of the motor vehicle can be increased. If the vehicle has an internal combustion engine, the fuel consumption is reduced, resulting in low emissions. In addition, the wear of the vehicle, in particular the hydraulic brake system, in the

Compared to a situation with a view from the driver to low Schubrekuperation be reduced. In general, the amount of Schubrekuperationsmoments and the Schubrekuperationsleistung in overrun operation in the presence of the

Recuperation mode with increased Schubrekuperation higher than without

Switchover to operation with increased Schubrekuperation. However, this is not always mandatory. For example, this is the same

Requirements (eg same vehicle speed, same gradient of the gradient), if the Schubrekuperationsmoment or the

Schubrekuperationsleistung depends on these conditions. It would be conceivable that the recuperation torque set in the overrun mode after switching over in the recuperation mode with increased

Schubrekuperation in amount is slightly less than before switching, for example, if the amount of the set Schubrekuperationsmoments increases with increasing inclination of the slope and after switching the slope of the slope decreases sharply.

It is advantageous if switching to the recuperation mode with increased Schubrekuperation is triggered only in connection with a downhill and not on a route in the plane.

For this purpose, it can be checked whether there is a downhill run. It is switched to the recuperation mode with increased Schubrekuperation depending on whether the presence of a downhill was determined.

For example, a variable that is characteristic of the grade of a grade is determined (eg, the grade, the slope force or one of the

Downhill force corresponding moment, z. B. as a wheel torque). A threshold comparison is then made between the magnitude characteristic of the grade and a threshold. The

Switching to the recuperation recuperation mode with increased recuperation is then dependent not only on the sensing of a brake pedal application, but also on the result of the threshold comparison, which indicates the presence of downhill travel.

Advantageously, the method has a possibility for the driver to switch to the recuperation with increased

Reverse recuperation, d. H. that the vehicle is in

Push operation is operated again with the original prior to switching not increased Schubrekuperation.

Typically, the vehicle includes a driver-operable accelerator pedal that can be used to accelerate the vehicle and whose operation is used to initiate retraction of the increased-Schubrekuperation Rekuperationsmodus. Preferably, it is checked after switching to the Rekuperationsmodus with increased Schubrekuperation whether an operation of the accelerator pedal is present. For example, that will as a function of the accelerator pedal angle in an accelerator pedal interpreter determined driver's desired torque evaluated and, for example, checked whether the driver's desired torque is greater than a threshold value, for example, greater than zero. It is preferably switched back again when the driver's desired torque is in the positive range. For the downshift, it may be necessary, in particular, for the driver's desired torque to be in the positive range for a certain minimum time duration or minimum travel distance before the switchover is triggered. In response to an operation of the driver's pedal (for example, when the driver's desired torque is greater than the threshold value), the switchover to the recuperation mode with increased Schubrekuperation so

taken back, so that in the case of overrun the original level of Schubrekuperation is used again. For example, is switched back to the original level of Schubrekuperation in already light operation of the accelerator pedal. The switching back in response to an operation of the accelerator pedal makes sense against the background that then a reduction in Schubrekuperation for the driver is not noticeable, since then in general no Schubrekuperation is present anyway.

In addition, it would be conceivable to automatically reverse the shift to the recuperation mode with increased Schubrekuperation when driving uphill or when driving in the plane. For example, a characteristic of the inclination of the road surface size (for example, an inclination angle, a downhill force or a corresponding moment) are compared to a threshold. In the event that the threshold comparison shows that an incline is uphill, which is greater than or greater than the threshold associated with the threshold, the switching in

Recuperation mode with increased Schubrekuperation be automatically withdrawn. There are several possibilities imaginable when in response to a

Operation of the brake pedal is switched to the recuperation with increased Schubrekuperation. According to a first possibility is still during the operation of the brake pedal and the resulting delay effect

(For example, due to the hydraulic brake system and / or Bremsrekuperation) in the recuperation mode with increased

Schubrekuperation switched. In this case, there is a possibility that the driver during braking when switching over in the

Rekuperationsmodus with increased Schubrekuperation by the noticeable increase in the delay effect receives a response that a switch has taken place. This behavior is similar to that

Downshifting to a lower gear in a conventional ICE drive.

In the recuperation with increased Schubrekuperation so can be switched according to the first option during the operation of the brake pedal, so that after switching through the increased

Schubrekuperation a (opposite to by the operation of the

Brake pedal induced delay effect) increased

Delay effect occurs. This increased delay effect then feels the driver and knows that a switch has taken place. However, the increase in recuperation for the driver could initially be incomprehensible because it is not clear how the downshift in a conventional internal combustion engine drive by a changed engine noise and a change in the indicated speed.

According to a second possibility, the switching can also take place at the end of the braking. It is in the Rekuperationsmodus with increased Schubrekuperation approximately switched when at the end of the operation of the brake pedal caused by the operation of the brake pedal decelerating effect. The exact course of Schubrekuperation preferably depends on the release speed of the brake pedal, since typically the Bremsrekuperation is reduced ramped in dependence on the release speed of the brake pedal. For example, upon termination of the operation of the brake pedal, the Schubrekuperation is increased while the Bremsrekuperation is reduced simultaneously. However, unlike the first option, the driver then receives no feedback on the increase in Schubrekuperation and therefore may have no reason to increase the foot of the brake pedal, and will continue to press this. The brake could be unnecessarily loaded continuously. According to a third possibility, the recuperation mode with increased Schubrekuperation shortly after the start of the actuation of

Brake pedal to be switched. For example, in the

Recuperation mode with increased Schubrekuperation switched when a influenced by the operation of the brake pedal size (eg, a brake pedal angle, a brake pressure or the amount of

Bremsrekuperationsmoments) is greater than or greater than a threshold value.

Preferably, the set Schubrekuperation depends in

Rekuperationsmodus with increased Schubrekuperation from the degree of the slope in the downhill from. For the degree of the slope may be a characteristic size (for example, the inclination angle, a

Downhill power or a momentum output corresponding torque) are determined, which is then taken into account in increasing the Schubrekuperation. As a result, for example, a certain, fixed target acceleration or target speed can be achieved with varying degrees of the gradient. The characteristic of the grade of the slope Size (eg the downhill force) can also be taken into account, for example, in the manner in which the shear recuperation is increased such that the force corresponding to the increase in shear recuperation (ie the additional retarding force) has a certain percentage (eg 60%). ) correspond to the slope force. The percentage, in turn, may depend on the current slope of the slope. Instead of relating to forces, this approach can also be applied to moments, deceleration / acceleration values or other variables characteristic of these forces, such that, for example, increasing the amount of Schubrekuperationsmoments (ie the additional

Schubrekuperationsmoment) corresponds to a certain percentage of a downhill torque corresponding moment. It is therefore preferably considered the slope force in such a way that a certain proportion of the slope force by increasing the

Schubrekuperation is adopted (i.e., is compensated). The proportion, in turn, may depend on the current slope of the gradient; but the proportion can also be constant over the angle of inclination. Preferably, however, the vehicle should not be slowed downhill, undesirably, without braking, i. there should be no overcompensation of

Downgrade force take place.

Preferably, therefore, the increase in Schubrekuperation is zero when the slope is zero. It can be provided that with an increase in the slope of the slope above a certain slope of the influence of this slope

added additional downgrade force through the increased

Schubrekuperation is fully compensated, so that a further increase in acceleration is avoided with increasing inclination of the slope, that is, the acceleration remains constant from this particular slope. To set the Schubrekuperation a manipulated variable is typically specified, which is then implemented accordingly. The Schubrekuperation example, over a given

(Desired) Schubrekuperationsmoment or a predetermined

(Desired) Schubrekuperationsleistung for the one or more electric machines controlled or regulated.

For the recuperation mode with increased Schubrekuperation is one for the increased Schubrekuperation or for increasing the

Schubrekuperation characteristic manipulated variable, in particular one of

Amount her increased or additional Schubrekuperationsmoment or an increased or additional Schubrekuperationsleistung determined in dependence of a characteristic of the degree of incline in the downhill control variable.

The increased Schubrekuperation can be adjusted so that the

Acceleration of the vehicle in Rekuperationsmodus with increased recuperation in overrun is greater than zero; For this purpose, a characteristic of the slope size can be considered. The vehicle is therefore preferably not slower downhill in overrun, as this may not be comprehensible to the driver. For example, care is taken that the Schubrekuperation (eg the amount of

Schubrekuperationsmoment or the Schubrekuperationsleistung) does not exceed a defined maximum level, so that the vehicle does not slow downhill by increasing the Schubrekuperation.

When increasing the Schubrekuperation should also be taken to ensure that the driving stability of the vehicle does not suffer from the increase in Schubrekuperation.

For the recuperation mode with increased shear recuperation

For example, a target acceleration of the vehicle or one for this purpose characteristic size specified; this can be fixed or variable. For example, the size of the vehicle speed depends.

So that the vehicle does not slow down in overrun, the

Target acceleration preferably greater than or equal to zero; But it would also be conceivable a negative target acceleration, in particular a only slightly negative target acceleration. The increased Schubrekuperation for the

Recuperation mode with increased Schubrekuperation is then adjusted so that the acceleration of the vehicle in recuperation with increased Schubrekuperation in overrun the predetermined

Target acceleration corresponds to, for example, a predetermined positive target acceleration or a predetermined target acceleration of zero.

It can be provided that the target acceleration can be set by the driver, for example directly via a separate operating element or indirectly via an operating element for selecting a driving mode influencing the longitudinal dynamics of the vehicle (eg Eco, Sport, Comfort), the target acceleration then being from depends on the selected driving mode. For the Rekuperationsmodus with increased Schubrekuperation one for the increased Schubrekuperation or for increasing the

Schubrekuperation characteristic manipulated variable, z. B. an increased amount of Schubrekuperationsmoment or an additional increase corresponding Schubrekuperationsmoment or a corresponding power variable, depending on one or more of the following

Influencing variables are determined. An influencing variable, for example, a predetermined, for the target acceleration of the motor vehicle

characteristic size (for example, the target acceleration itself or a target acceleration-inducing torque amount). The target acceleration itself can again be speed-dependent.

For example, for low speeds (eg, speeds less than a limit speed of, for example, 50 km / h) uses a different target acceleration than for higher speeds.

A torque magnitude corresponding to the target acceleration may be used. This target acceleration torque quantity is preferably determined as a function of the vehicle speed. The background for this is, for example, that the torque to maintain a certain target acceleration is typically not over

Speed of the vehicle constant. In addition, a speed-dependent target acceleration may also be desired.

Alternatively or additionally, one for the air resistance of the

Motor vehicle characteristic size and / or characteristic for the rolling resistance of the vehicle size to determine the

Schubrekuperations manipulated variable can be used. As already described above, alternatively or additionally, a variable which is characteristic of the degree of the gradient can be used to determine the manipulated variable. Furthermore, alternatively or additionally, a variable characteristic of the drag torque of another drive unit can be used to determine the Schubrekuperations manipulated variable, if another drive unit in the motor vehicle is present (eg., An internal combustion engine in the case of a hybrid vehicle, if the

Internal combustion engine is not disconnected in overrun mode). The other drive unit is a drive unit that does not correspond to the electric drive unit that is used for the Schubrekuperation.

With regard to the actuation of the brake pedal can be provided that even a single operation of the brake pedal can cause a switch in the Rekuperationsmodus with increased Schubrekuperation. As soon as the brake pedal is pressed somehow during the descent, a switch to the recuperation mode with increased Schubrekuperation caused. Switching to the

Recuperation mode with increased Schubrekuperation can also be linked to another condition or more cumulative other conditions. In addition, several alternative ways may be provided to enter the recuperation mode with increased

To switch Schubrekuperation.

For example, as a condition for switching to the

Recuperation mode with increased Schubrekuperation the presence of a multiple (eg double) operation of the brake pedal tested during downhill. As a result, a typical driving behavior can be identified, in which the driver repeatedly taps on the brake pedal when the Schubrekuperation is too low from the driver's point of view. For example, it is checked whether a multiple operation of the

Brake pedal during a predetermined period of time (eg 10 s) or during a predetermined driving distance (eg 300 m), z. B. a double actuation of the brake pedal during the given

Duration or the given route. For example, one condition for switching to the increased Schubrekuperation recuperation mode being tested is whether an increase in vehicle speed during downhill travel is greater than or equal to a threshold. If the condition is met, switching to the recuperation mode with increased Schubrekuperation is triggered, otherwise not. The underlying of this condition

The idea is that with an increase in the vehicle speed greater than or equal to the threshold value of the driver by increasing the

Schubrekuperation is relieved. From the perspective of the driver takes the

Speed too fast or not fast enough.

For example, it is checked whether a speed increase between two brakes meets a certain criterion. Preferably, in the case a double operation of the brake pedal determines the vehicle speed at the end of the first operation of the brake pedal and compared with the vehicle speed occurring during a second, subsequent to the first operation of the brake pedal vehicle speed. If the speed increases by more than a certain threshold (for example in the range of 2 to 5 km / h) compared to the speed at the end of the first actuation, a change in the

Recuperation mode triggered with increased Schubrekuperation. If the speed increase is less than the threshold, none will be

Switching triggered.

It can be checked as a condition for switching to the Rekuperationsmodus with increased Schubrekuperation the presence of a permanent operation of the brake pedal. For example, it checks if the

Operation period is greater than or equal to a given period of time. As a result, for example, a behavior can be detected in which the driver can brake the brake during deceleration of the vehicle during downhill driving. For switching to the recuperation mode with increased

Schubrekuperation can be required, for example, that in case of a permanent operation of the brake pedal, the speed increase within a period of observation is greater than or greater than a predetermined threshold. For example, the

Increasing the speed since the brake pedal was actuated, continuously checking whether the speed increase is greater than or greater than a predetermined threshold value.

It can be provided that the current degree of the slope has an influence on whether already a single operation of the brake pedal for

Switching leads or whether one or more other conditions, such as a multiple operation of the brake pedal, in particular within a given time interval, must be met for switching to occur.

For this purpose, it is preferable to determine a variable which is characteristic for the degree of the gradient, as has already been described above. There will be a threshold comparison between the for the degree of the gradient

characteristic size and a threshold value. For the first case that the threshold comparison indicates that the gradient is steeper than a slope associated with the threshold value, switching to the recuperation mode with increased Schubrekuperation is already triggered by a single operation of the brake pedal. For the second case, the threshold comparison indicates that the slope is flatter than the slope

Threshold assigned slope is the switching to the

Recuperation mode with increased Schubrekuperation in addition to the operation of the brake pedal to one or more additional conditions, the fulfillment of which is not required in the first case for switching, for example, a multiple operation within a predetermined period, especially under the additional condition of satisfying a speed criterion described above.

For example, if the grade is particularly steep, a single press of the brake pedal will immediately result in a switch, while on a flat grade, one or more additional conditions other than simply depressing the brake pedal will have to be met.

It may be that switching to the recuperation mode with increased Schubrekuperation is prevented in certain driving situations, for example in a driving situation when a driver assistance system (for example, a speed control system, in particular a

Cruise control or a Abstandstempomat) controls the longitudinal guidance of the vehicle. Switching could also be prevented in one

Driving situation with active vehicle dynamics control. Alternatively or in addition switching over can be prevented in a curve situation critical for the stability of the vehicle; for the detection of such

Curve situation, for example, the steering angle and / or the

Transverse acceleration of the vehicle are evaluated and compared with a respective threshold. Alternatively or additionally, switching over in a driving situation with a vehicle speed greater than or equal to a limit speed can be prevented. Switching can also be prevented if a certain

Driving mode (eg sport) from a plurality of different, the longitudinal dynamics of the vehicle influencing driving modes was selected by the driver, especially if the selected driving mode has a higher Schubrekuperation than another driving mode in which a switch is not prevented. Alternatively or additionally, the switching can be prevented even in the case of a gradient with a low slope.

There are preferably provided (in addition to the Rekuperationsmodus with normal, not increased recuperation) at least two different Rekuperationsmodi each with increased Schubrekuperation, namely a first Rekuperationsmodus with increased Schubrekuperation and a second recuperation with respect to this first Rekuperationsmodus still further increased Schubrekuperation. Starting from the

Recuperation mode with no increased Schubrekuperation is switched in response to the detection of an operation of the brake pedal during a downhill in the first recuperation, as already described in detail above. Starting from the first recuperation mode, in response to detecting an actuation of the brake pedal during a descent into the second

Recuperation be switched. Here, the above statements on the advantageous and exemplary embodiments of the method apply in the same way for switching to the second

Recuperation. In addition, n recuperation modes can generally be used with increased Schubrekuperation be provided, for example, n = 2, 3 or 4, starting from an i-th recuperation with increased

Recuperation in response to detecting an actuation of the

Brake pedal switching to the i + 1-th recuperation with increased Schubrekuperation occurs (with i = 1, n -1).

The increase of the shear recuperation from the i-th recuperation mode to the i + 1-th recuperation mode should not be less than one

Minimum increase, otherwise the increase in Schubrekuperation may not be felt by the driver. If the increase is too small, fewer recuperation modes can be used, but with a greater difference in shear recuperation.

At least two different Rekuperationsmodi can be provided, each with a different increased Schubrekuperation, starting from a Rekuperationsmodus with not increased recuperation in response to determining an operation of the brake pedal during a downhill depending on one or more decision variables either in the first or second Rekuperationsmodus

is switched. For example, a decision size may be a characteristic of the grade of the grade. For example, the second recuperation mode is switched when the degree of the

Gradients greater than a threshold, and in the first

Recuperation mode switched when the grade of the slope is smaller than the threshold value. In this case, the recuperation in the second recuperation mode is preferably higher than the recuperation in the first recuperation mode. A decision variable may alternatively or additionally also be an indication corresponding to the currently selected drive mode: For example, in the case of a low-Schubrekuperation (eg, Eco-drive mode) drive mode, in response to an operation of the brake pedal in the second recuperation mode

Schubrekuperation switched, while in the case of a driving mode with higher Schubrekuperation (eg Comfort driving mode) is switched in response to an actuation of the brake pedal in the first recuperation with increased Schubrekuperation. In this case, the recuperation in the second recuperation mode is preferably higher than the recuperation in the first recuperation mode.

Basically, it can be provided that the switching in the

Recuperation mode with increased Schubrekuperation of the currently selected driving mode of a plurality of different, the longitudinal dynamics of the vehicle influencing, selectable driving modes depends. For example, switching is permitted in a first driving mode (eg Eco), while switching in another, second driving mode (eg sport) is not possible. In this first driving mode, in which a switching is allowed, it is a driving mode, which has a lower Schubrekuperation in overrun mode (without increasing the Schubrekuperation) than the second driving mode (see

For example, Fig. 2). Since the second driving mode has a higher Schubrekuperation anyway, the increase of the invention is the

Schubrekuperation not necessary depending on the level of Schubrekuperation.

It may also be provided that switching over is only permissible in a single driving mode of the overall selectable driving modes,

preferably in the driving mode (eg Eco), which has the least Schubrekuperation in overrun (without increasing the Schubrekuperation) compared to the other driving modes (eg Sport, Comfort).

Alternatively or additionally, the degree of increase in

Schubrekuperation in Rekuperationsmodus with increased Schubrekuperation of the currently selected driving mode of a plurality of

different, depending on the longitudinal dynamics of the vehicle, selectable driving modes depend; ie the selected driving mode has an influence on how much the Schubrekuperation is increased. For example, in a first drive mode (eg, Eco), the increase in Schubrekuperation is greater than in a second drive mode (eg, Sport). In this first driving mode, in which the increase in Schubrekuperation is higher, it is a driving mode, which in overrun (without increasing the Schubrekuperation) has a lower Schubrekuperation than the second driving mode (see, for example, Fig. 2). Since the second driving mode already has a higher Schubrekuperation, the inventive increase in Schubrekuperation for the second driving mode can be selected to be lower than in the first driving mode.

A second aspect of the invention relates to a control device for

Setting an effective thrust operation Schubrekuperation a motor vehicle with at least one usable for recuperation

electric machine. The control device is set up, a

During a descent, actuation of the brake pedal is detected, and in a recuperation mode with increased acceleration in response to detecting actuation of the brake pedal during a downhill ride

To switch Schubrekuperation. The control device is, for example, a

Motor control unit for controlling an electric machine that can be used both as a drive machine and as a generator.

The above statements on the method according to the invention according to the first aspect of the invention also apply correspondingly to the control device according to the invention according to the second aspect of the invention. Not explicitly described here advantageous

Embodiments of the control device correspond to those described above or described in the claims

Embodiments of the method according to the invention. The invention will be described below with reference to an embodiment with the aid of the accompanying drawings. In these show:

Fig. 1 shows an embodiment of the inventive method for

Adjusting the shear recuperation;

Fig. 2 exemplary courses of the amount not increased

Schubrekuperationsmoments M EM.schubreku on the

Vehicle speed v for different driving modes;

FIG. 3 shows exemplary profiles of different sizes over time t; FIG. and

4 shows exemplary courses of different sizes over time t. In Fig. 1 is a schematic flow diagram of an embodiment of the method according to the invention is shown. In the query 100, it is first checked whether there is a downhill run.

For this purpose, for example, a variable which is characteristic for the degree of the gradient is determined, and a threshold value comparison is carried out between the variable characteristic for the degree of the gradient and a threshold value. For example, a slope-output torque slope is continuously determined, which corresponds to a torque corresponding to the slope-down force, for example a wheel torque. The sign of the

Downhill torque Mnang is such that the

Slope output torque is positive on a grade and negative on a positive grade. If then the slope output torque MHang is greater than or greater than a positive threshold MHang.si, the presence of a downhill is assumed. If a downhill run according to the query 100 was positively recognized, it is continuously checked whether the brake pedal is actuated by the driver (see query 120). When an operation of the brake pedal has been detected, according to a simpler embodiment, a switch to a

Recuperation mode with increased shear recuperation (see step 130). There are several conceivable options at the time of switching over, which will be discussed later. If the accelerator pedal is not actuated and the driver's desired torque MFW ^ 0 (see query 140), the recuperation mode with increased Schubrekuperation remains. When the accelerator pedal is depressed and the driver demand torque MFW becomes greater than 0, it is returned to the original recuperation mode with non-increased

Schubrekuperation switched over (see step 150).

In accordance with an extended embodiment, in general, a simple operation of the brake pedal for switching to the ranges

Recuperation mode with increased Schubrekuperation not sufficient, instead, the switch to the Rekuperationsmodus is linked to the fulfillment of one or more conditions that affect the operation of the brake pedal.

In the expanded embodiment variant, for example, according to a first switching possibility, at least two actuation of the brake pedal within a time interval is required. It will be the

Vehicle speed VBI determined at the end of a first brake pedal operation and compared with the vehicle speed VB2 during the subsequent second brake pedal operation. If the

Speed increase Δνι = VB2 - VB I is greater than a threshold Avi s, switching to the recuperation with increased

Schubrekuperation (see step 130), otherwise the switching is omitted despite repeated operation of the brake pedal. It can also be a second switching option in the extended

Embodiment be provided: Here, a longer operation of the brake pedal is required, for example, stops longer than a predetermined minimum period of time. In addition, it is required to switch over that the speed increase ÄV2 = VE - VB between the

Vehicle speed VB AT the beginning of the braking and the current vehicle speed VE is greater than a threshold ÄV2, s. If this condition is met, switching to the recuperation mode with increased Schubrekuperation (see step 130); otherwise the switching is omitted despite prolonged operation of the brake pedal.

Furthermore, in the expanded embodiment, a third

Switching be provided, in which at a high slope of the gradient switching is triggered even with a simple operation of the brake pedal. For this purpose, a threshold value comparison between a characteristic of the degree of the gradient size, such as

Downhill torque Mhang, and a threshold value performed. If the slope positive positive slope torque is greater than a positive threshold MHang, s, 2 (with MHang, s, 2> Mhiang.si), there is a steep slope, so that even with simple operation of the brake pedal switching to the recuperation with increased Schubrekuperation is triggered.

In the extended embodiment, a switch in the

Rekuperationsmodus with increased Schubrekuperation be triggered either after the first switching possibility, after the second switching option or the third switching possibility. Of course, it would be conceivable that not all three switching options, but only one or two of the switching options described above are implemented in the extended embodiment. In recuperation mode with increased Schubrekuperation (see step 130), a Schubrekuperationsmoment is made in overrun, which is the sum of the not increased from the amount

Schubrekuperationsmoment MEM, Schubreku (which is provided without switching) and an additional Schubrekuperationsmoment .DELTA.Μ EM, thrust Recoil results. It is assumed below that in the case of a

Recuperation is not increased in magnitude Schubrekuperationsmoment MEM.schubreku is negative and the additional Schubrekuperationsmoment AME .schubreku is negative or zero (of course, could also be used with inverted sign).

The Schubrekuperationsmoment MEM .schubreku not increased from the amount is determined as a function of the vehicle speed v and preferably additionally depends on the selected driving mode influencing the longitudinal dynamics (eg, Eco). FIG. 2 shows exemplary courses of the thrust recuperation torque MEM .schubreku over the vehicle speed v for different driving modes, which is not increased in magnitude. The Schubrekuperationsmoments MEM .schubreku not increased from the amount is chosen as a function of the speed v so that above the speed v results in a fixed vehicle deceleration, the vehicle deceleration is the greatest in the driving mode Sport. As can be seen from FIG. 2, the travel mode Eco has a lower one

Schubrekuperation as the driving modes Comfort and Sport on. The driving mode Eco is very subdued and flat: with relatively much accelerator pedal change, little acceleration is caused in the

Push operation is caused by the Schubrekuperation little delay effect. The Eco driving mode is comfortable and helps the driver to drive as evenly as possible in order to achieve the lowest possible fuel consumption. The driving mode sport is very direct and steep: with relatively little accelerator pedal change much acceleration is caused, in overrun is the Schubrekuperation a high Delay effect achieved. This driving mode is very sporty and helps the driver to experience a high level of driving pleasure and to achieve optimum driving performance. In the plane, the driver has to work less with the accelerator pedal and the brake pedal when selecting the driving mode Eco compared to the driving mode Sport.

In the presence of a gradient, the behavior is reversed: The driver can comfortably the slope when choosing the driving mode Sport with a higher deceleration effect due to the higher Schubrekuperation

while the driver has to work much more with the brake pedal when selecting the driving mode Eco. This results in lower energy efficiency and is associated with a lower ride comfort. By switching to the recuperation mode with increased

Schubrekuperation in response to a brake pedal operation, these disadvantages can be avoided; In overrun conditions, it is then possible to benefit from increased shear recuperation in terms of energy efficiency and comfort. The driving modes can even be further developed, since the disadvantage of downhill driving in a driving mode with low

Schubrekuperation (here: Eco) can be partially or even completely compensated by the invention switching the Schubrekuperation.

The additional Schubrekuperationsmoment ΔΜΕΜ .schubreku (with ΔΜ EM, schubreku <0) is dependent on a vehicle target acceleration

corresponding target torque (with Mziei> 0), an air torque corresponding to the air resistance N (with MLU "<0), a rolling moment corresponding roll torque MROII (with MROIII <0), one of

Slope output force corresponding slope down torque Mnang (hang> 0), for example, calculated in the following form: MLuft + MROII + Mhang + MvM, drag + MEM.schubreku + AMEM.schubreku = Mziei

ΔΜ EM, thrusting recharge = Mziei - MLuft - MROII - Mhang - MEM.pickreku - MvM, drag The size Mv, schie _PP corresponds to the drag torque of an internal combustion engine. If no combustion engine is provided in addition to the electric drive or the combustion engine is decoupled in overrun anyway, this size can be deleted in the equation. The above-mentioned torque quantities are preferably wheel torque quantities that are based on one or more

Vehicle wheels are related. For example, it may be provided that not all quantities from the formula above are present as individual quantities. For example, the sum MLUK + M OII + MHang can be determined as a magnitude while driving and calculated in dependence on ΔΜΕΜ .schubreku.

The target torque Mziei, the air momentum Mum, the roll moment MR ₀ II and the amount of thrust not increased Schubrekuperationsmoment ME .schubreku are determined as a function of the vehicle speed v.

In Fig. 2 is an exemplary additional Schubrekuperationsmoment .DELTA.Μ EM thrust rechu at a certain vehicle speed v

located. The Schubrekuperationsmoment set in Rekuperationsmodus with increased Schubrekuperation corresponds to the sum of M EM, Schubreku + ΔΜ EM, Schubreku. Care must be taken that the set Schubrekuperationsmoment MEM.schubreku + AMEM.schubreku does not exceed a certain limit of vehicle stability (this is shown in dashed lines in Fig. 2). In addition, the sum should be MEM .schubreku ⁺

AE .schubreku not below the limit MEM.schubreku + AMEM.schubreku.max. The size AMEM.schubreku.max corresponds to the maximum additional Schubrekuperationsmoment of the amount with minimum target acceleration (see the formula later in the text). According to an alternative calculation variant, the additional

Schubrekuperationsmoment AMEM.schubreku be calculated in the following manner: AMEM.schubreku = - X * Mhang ► AMEM.schubreku = - X * Mhang

The quantity x can be constant, but the quantity x can also be a function of a parameter, for example a variable which is characteristic for the inclination of the gradient, for example x = f (MHang).

It may further be provided that after switching to the (first) recuperation mode with increased Schubrekuperation another

Umschaitung from the first Rekuperationsmodus with increased Schubrekuperation in response to another brake pedal operation in a second Rekuperationsmodus with (compared to the first

Rekuperationsmodus with increased Schubrekuperation) even further increased Schubrekuperation can be triggered. In this second

Recuperation mode is the amount of the Schubrekuperationsmoments against the not increased from the amount ago Schubrekuperationsmoment ME .schubreku increased by the additional Schubrekuperationsmoment AM * EM.schubreku, with | ΔΜ * EM.schubreku I> | ΔΜ EM.schubreku I. The extra

Schubrekuperationsmoment ΔΜ EM.schubreku is calculated, for example, in the same way as ΔΜ EM.schubreku, namely AM * EM, schubreku = M * target - MLuft - MROII - Mhang - MEM.schubreku - MvM. Schlepp, but for example, unlike the calculation of

AMEM.schubreku a lower target acceleration M * ziei is used, so that the amount of ΔΜ EM.schubreku greater than the amount of ΔΜΕΜ .schubreku is. FIG. 2 shows an example of an additional additional Schubrekuperationsmoment .DELTA.Μ EM ubreku.

It would also be conceivable, starting from a recuperation mode with not increased recuperation in response to the detection of an actuation of the brake pedal during a downhill as a function of one or more decision variables optionally in the first

Rekuperationsmodus with the additional Schubrekuperationsmoment .DELTA.E EM.schubreku or the second Rekuperationsmodus with the additional Schubrekuperationsmoment AM * EM, Schubreku is switched.

Not only two recuperation modes with increased Schubrekuperation, but any number n of Rekuperationsmodi i with increased Schubrekuperation conceivable, each having a different additional Schubrekuperation ΔΜΕΜ, schubreku, i have. The additional

Schubrekuperation ΔΜΕΜ, schubreku, i the individual Rekuperationsmodi i corresponds for example kr krEM.schubreku.max, with ki greater than 0 and less than 1. The size AMEM.schubreku.max corresponds to the maximum additional Schubrekuperation from the amount ago. The factors ki of the individual recuperation modes i are calculated as i / n, d. H.

1 / n, 2 / n .., (n-1) / n, 1.

The size AME .schubreku.max is calculated, for example, as follows: AMEM.schubreku.max = Mziel.min - Ml_uft - M OII - Mhlang - MEM.pickreku - vM, Tow

In the equation, Mziei.mm describes the minimum target torque, which in turn corresponds to the lowest target acceleration. The lowest target acceleration may be 0, for example.

The difference in additional shear recuperation .DELTA., Thrust recovery, i between adjacent recuperation modes should not be less than a minimum value, otherwise the increase in shear recuperation of the Driver may not be noticeable when changing the recuperation mode. If the increase is too small, fewer recuperation modes can be used, but then have a larger difference in the additional thrust recuperation ΔΜΕΜ.schubreku.

In Fig. 3 is an exemplary course of the brake pedal operation (diagram a), an exemplary course of the accelerator pedal operation (diagram b), an exemplary course of the slope output torque MHang (diagram c) and an exemplary course of the set recuperation moment ME .reku (diagram d) via the time t shown. It is from the simple

Design variant assumed. At the beginning neither accelerator pedal nor brake pedal are actuated and the vehicle is in overrun mode, wherein the electrical machine of the electric drive with a set

Schubrekuperationsmoment MEM .schubreku is operated. The

Downhill momentum MHang increases during the downhill run, so that the vehicle is strongly accelerated. At time ti, a

Brake pedal operation by the driver to the high

Vehicle acceleration to counteract. By pressing the brake pedal, the set recuperation torque is a

Bremsrekuperationsmoment MEM. remsreku increased in amount; it then occurs by an additional delay effect. When, at the completion of the operation of the brake pedal, the deceleration effect caused by the operation of the brake pedal decreases approximately at the time .2, the recuperation mode with increased Schubrekuperation

switched. Starting from the value zero, the amount of the

additional Schubrekuperationsmoment ΔΜΕΜ .schubreku ramp increases, while the amount of Bremsrekuperationsmoments MEM .bremsreku

is reduced in a ramp. This is below diagram (d)

sketched schematically. The resulting recuperation moment MEM.reku should have as few jumps as possible. The amount of the resulting recuperation torque MEM.reku is reduced to the amount of the sum MEM .schubreku + ΔΜ EM, thrust reserve. At time h, the downhill torque decreases Mhang too, as the slope gets steeper. According to the above-described equation for determining AMEM.schubreku, the amount of the here negative magnitude AMEM.schubreku increases. If at time t ₄ the downhill torque decreases again, the amount of

AMEM.schubreku lower again.

At time ts, the accelerator pedal is actuated, thus leaving the overrun mode. This switches back to the recuperation mode with no increased Schubrekuperation, so that after completion of the operation of the accelerator pedal at the time te in the subsequent overrun again from the amount not increased Schubrekuperationsmoment MEM.schubreku is set without additional Schubrekuperationsmoment AMEM .schubreku. FIG. 4 shows an exemplary course of the brake pedal actuation (diagram a), an exemplary course of the accelerator pedal actuation (diagram b), an exemplary course of the downhill torque MHang (diagram c) and an exemplary profile of the set recuperation torque MEM.reku (diagram d) the time t shown. Only the diagram d in FIG. 4 differs from the diagram d in FIG. 3. In contrast to FIG. 3, in an alternative implementation of the method, during the actuation of the brake pedal, the system is switched to the recuperation mode with increased Schubrekuperation, ie. H. increases the Schubrekuperationsmoment of the amount. After building the additional

Schubrekuperationsmoments AMEM.schubreku results in a resultant Rekuperationsmoment the electric machine of MEM.reku = MEM.schubreku + AM EM, thrustreku + MEM.bremsreku. The driver receives during the operation of the brake pedal by the increased due to AMEM .schubreku

Delay effect a feedback that the

Schubrekuperationsmoment was increased in amount.

Claims

claims

1 . Method for changing an overrun mode

Schubrekuperation of a motor vehicle with at least one usable for recuperation electric machine, which includes an operable by the driver brake pedal, with the steps performed by the motor vehicle steps:

- detecting (20) an operation of the brake pedal during a downhill ride; and

- Switching (130) into a recuperation mode with increased

Schubrekuperation in response to the detection of an operation of the brake pedal during downhill driving, wherein in recuperation with increased Schubrekuperation after completion of the operation of the brake pedal in overrun an increased Schubrekuperation is effective.

2. The method of claim 1, comprising the step:

- determining (100) the existence of a downhill run,

wherein is switched to the recuperation with increased Schubrekuperation depending on the fact that the presence of a downhill was determined.

3. The method according to any one of the preceding claims, comprising the steps:

- determining a characteristic of the degree of the slope size; and - Performing a threshold comparison between the characteristic of the degree of the slope size and a

threshold value,

wherein the switching to the recuperation recuperation mode depends on the result of the threshold comparison.

4. The method of claim 1, wherein the vehicle has an accelerator pedal that can be actuated by the driver, and the method has the additional steps after switching to the recuperation mode with increased Schubrekuperation:

- detecting (140) an actuation of the accelerator pedal; and

- canceling (150) switching to the

Recuperation mode with increased Schubrekuperation in response to detecting an operation of the accelerator pedal.

5. The method according to any one of the preceding claims, wherein

- During the operation of the brake pedal one through the

Actuation of the brake pedal caused

Delay effect occurs and

- in the recuperation mode with increased Schubrekuperation

is switched during actuation of the brake pedal, so that after switching by the increased Schubrekuperation one compared to by the operation of the brake pedal

caused delay effect increased delay effect occurs.

6. The method according to any one of claims 1 to 4, wherein

- During the operation of the brake pedal one through the

Actuation of the brake pedal caused

Delay effect occurs and

- in the recuperation mode with increased Schubrekuperation

approximately then (.2) is switched, if at the end of the Actuation by pressing the brake pedal

caused delay effect diminishes.

7. The method according to any one of claims 1 to 4, wherein in the

Recuperation mode with increased Schubrekuperation is switched shortly after the start of the operation of the brake pedal.

8. The method according to any one of the preceding claims, wherein for the Rekuperationsmodus with increased Schubrekuperation

one for increased shear recuperation or

- one for the increase of Schubrekuperation

characteristic size, in particular an increased or additional Schubrekuperationsmoment (AMEM.sc ubreku), depending on a characteristic of the degree of slope in the downhill slope size (MHang) is determined.

9. The method according to any one of the preceding claims, wherein the increased Schubrekuperation for recuperation with increased recuperation is set so that the acceleration of the vehicle in the recuperation with increased Schubrekuperation in overrun is greater than or equal to zero.

10. The method according to any one of the preceding claims, wherein

- For the Rekuperationsmodus with increased Schubrekuperation a target acceleration of the vehicle or one for this purpose

characteristic size is given, the

Target acceleration is in particular greater than or equal to zero, and

the increased Schubrekuperation for recuperation with increased Schubrekuperation is set so that the

Acceleration of the vehicle in recuperation mode with increased Schubrekuperation in overrun the predetermined target acceleration corresponds.

1 1. Method according to one of the preceding claims, wherein for the Rekuperationsmodus with increased Schubrekuperation

one for increased shear recuperation or

- one for the increase of Schubrekuperation

characteristic size (AME .sc ubreku) is determined as a function of one or more of the following variables:

- One for the target acceleration of the motor vehicle

characteristic size;

- A characteristic of the air resistance of the motor vehicle size;

- A characteristic of the rolling resistance of the motor vehicle size;

- a characteristic of the grade of the slope size (Mhang);

one for the drag torque of another drive unit

characteristic size, if another drive unit is present in the motor vehicle.

12. The method according to any one of the preceding claims, wherein as a condition for switching to the Rekuperationsmodus with increased Schubrekuperation the presence of a multiple, in particular double, operation of the brake pedal during downhill testing is checked, in particular during a predetermined period of time or a predetermined route.

13. The method according to any one of the preceding claims, wherein as a condition for switching to the Rekuperationsmodus with increased Schubrekuperation the presence of a permanent

Operation of the brake pedal is checked, in particular a

Operation duration greater or equal to a given period of time.

14. The method according to any one of the preceding claims, wherein it is checked as a condition for switching to the Rekuperationsmodus with increased Schubrekuperation whether an increase in the vehicle speed greater than or equal to one

Threshold is, in particular

- In the case of multiple actuation of the brake pedal between the end of a first operation of the brake pedal and during a second, subsequent to the first actuation of the brake pedal or

- in the case of a permanent operation of the brake pedal since the beginning of the operation of the brake pedal.

15. The method according to any one of the preceding claims, with the

steps:

- determining a characteristic of the degree of the slope size (MHang); and

Performing a threshold comparison between the magnitude (IvlHang) characteristic of the grade of the slope and a threshold value,

in which

in the first case that the threshold comparison indicates that the gradient is steeper than a gradient associated with the threshold, switching to the recuperation mode with increased

Schubrekuperation is already triggered by a single operation of the brake pedal and

for the second case that the threshold comparison indicates that the gradient is flatter than a slope associated with the threshold, the switching to the increased Schubrekuperation recuperation mode is linked to one or more additional conditions in addition to the operation of the brake pedal, the fulfillment of which in the first case is not required for switching.

16. The method according to any one of the preceding claims, wherein

- At least two different Rekuperationsmodi are provided with increased Schubrekuperation, namely a first

Recuperation mode with increased Schubrekuperation and a second Rekuperationsmodus with respect to this first

Rekuperationsmodus still further increased Schubrekuperation,

from a recuperation mode with no increased shear recuperation in response to the detection of a

Actuation of the brake pedal is switched during a downhill in the first recuperation mode, and

is switched from the first Rekuperationsmodus in response to the detection of an operation of the brake pedal during a downhill in the second Rekuperationsmodus.

17. The method according to any one of the preceding claims, wherein

Rekuperationsmodus even further increased recuperation, and

- Is switched on the basis of a Rekuperationsmodus with non-increased recuperation in response to the detection of an operation of the brake pedal during a downhill depending on one or more decision variables either in the first or the second Rekuperationsmodus.

18. The method according to any one of the preceding claims, wherein switching to the recuperation with increased

Schubrekuperation is prevented in at least one of the following driving situations: a driving situation with a driver assistance system controlling the longitudinal guidance of the vehicle;

a driving situation with active vehicle dynamics control;

- a curve situation;

a driving situation with a vehicle speed greater or greater than a limit speed;

if a certain driving mode is made up of a plurality of

different, the longitudinal dynamics of the vehicle

influencing driving modes was selected by the driver.

19. The method according to any one of the preceding claims, wherein

- Switching to the recuperation mode with increased

Schubrekuperation of the currently selected driving mode of a plurality of different, the longitudinal dynamics of the vehicle influencing, selectable driving modes depends, and / or

the increase in Schubrekuperation in Rekuperationsmodus with increased Schubrekuperation of the currently selected driving mode of a plurality of different, the

Longitudinal dynamics of the vehicle influencing, selectable driving modes depends.

20. The method according to any one of the preceding claims, wherein the motor vehicle is an electric vehicle, in particular an electric vehicle or a hybrid vehicle, wherein the electric drive comprises the electric machine

21. Control device for setting a thrust-effective Schubrekuperation of a motor vehicle with at least one usable for recuperation electric machine, which comprises an operable by the driver brake pedal, wherein the control device is set up, - to detect an operation of the brake pedal during a downhill, and

to switch to a recuperation mode with increased Schubrekuperation in response to the detection of an operation of the brake pedal during downhill driving, wherein in

Recuperation mode with increased Schubrekuperation after completion of the operation of the brake pedal in overrun an increased Schubrekuperation is effective.