JP2023118085A - Method for driving automobile, control device, and automobile - Google Patents

Abstract

To avoid an undesirable acoustic event, and missing of reaction force acting on a brake pedal.SOLUTION: An automobile includes a brake system having a pressure generation device which is controllable in operation, a hydraulic brake device, and an electric machine operable as a generator, can request a deceleration torque of the brake system by operation of the brake pedal and loosening of an accelerator pedal, and controls operation so as to achieve a total deceleration torque required at rotation speed higher than presettable limit rotation speed capable of an electric machine by only the electric machine according to a first deceleration torque required by the accelerator pedal and a second deceleration torque required by the brake pedal, and to shift the total deceleration torque required at rotation speed lower than the limit rotation speed to the brake device from the electric machine by operation control of the pressure generation device. At the rotation speed higher than the limit rotation speed, the first deceleration torque required by the accelerator pedal according to the second deceleration torque required by the brake pedal is reduced.SELECTED DRAWING: Figure 2

Description

The present invention is a method of driving a motor vehicle, the motor vehicle having a braking system comprising, on the one hand, a controllable pressure generator and at least one friction brake hydraulically connectable to the pressure generator. on the other hand, a braking system comprising an electric machine, the electric machine being operable as a generator to slow down the vehicle, an accelerator pedal and a brake pedal. , the actuation of the brake pedal and at least the release of the accelerator pedal, i.e. the non-actuation of the accelerator pedal or the transition of the accelerator pedal to its unactuated initial position, each require a deceleration torque of the brake system. , the braking device is adapted, depending on the first deceleration torque requested by the accelerator pedal and the second deceleration torque requested by the brake pedal, at driving speeds above a presettable limit rpm of the electric machine, The required total deceleration torque, in particular the total deceleration torque corresponding to the sum of the first and second deceleration torques, is realized only by the electric machine, and when the speed is below the limit speed, i.e. the speed is limited by the speed reduction process. It relates to a method that is operationally controlled such that, when dropping under rpm, the total deceleration torque required is transferred from the electric machine to the braking device by the operational control of the pressure generator.

Furthermore, the present invention relates to a computer program, a machine-readable recording medium and a control device.

A method of the form mentioned at the outset is already known in the prior art. To decelerate a motor vehicle, braking systems are generally used that have hydraulically actuable friction brakes, which generate a braking torque or force on each wheel of the motor vehicle, which decelerates the motor vehicle. In recent automobiles, the use of a brake device that can generate a braking force in a hydraulic circuit by controlling the operation of a pressure generator independently of the operation of the brake pedal is increasing. The pressure generator is, for example, a hydraulic pump driven by an electric motor, which in particular cooperates with the safety systems of the motor vehicle, for example the ESP system (ESP=Electronic Stability Program), for individual braking interventions. can be performed without operating the brake pedal. With the evolution of the electrification of vehicles and the development of drives with electric machines, there is also the possibility of regenerative braking, i.e. slowing down the vehicle by generator operation of one or more electric machines provided in the powertrain. , is recognized and especially optimized for improving the energy balance of the vehicle and reducing the wear of the mechanical friction brakes. Along with the development of electric vehicles, so-called one-pedal solutions are also being developed. With the one-pedal solution, the user can request both acceleration and deceleration torque by operating a single accelerator pedal. For this purpose, systems are known with which the driver can set a predetermined deceleration torque for the motor vehicle by completely releasing the accelerator pedal, whereby a It is possible to decelerate the vehicle to vehicle standstill without the use of a hydraulic braking system or the need to actuate the brake pedal.

Since the electric machine, however, loses efficiency in the low rpm range, especially during generator operation, the settable retarding torque also decreases with decreasing rpm, so that this It is known to transfer or transfer the deceleration torque provided by the electric machine up to the hydraulic brake system. The braking system is actuated by a pressure generator, so that hydraulic pressure is generated automatically, so that the driver does not have to actuate the brake pedal for this purpose, the hydraulic pressure being supplied to one or Acts on multiple friction brakes. The deceleration torque subsequently generated by the friction brake replaces the deceleration torque reduced by the electric machine. In particular, the electric machine and the braking system should be arranged in such a way that the electric machine and the braking system compensate each other, i.e. the friction braking torque increases and the electromechanical braking torque is reduced, in particular corresponding to the increase in the friction braking torque. , is controlled.

If the driver only uses the accelerator pedal during the deceleration process, this method can also be implemented without any problems and is comfortable. Hydraulic part of the brake system when the driver, by operating the brake pedal, however, requests a second deceleration torque which is higher, i.e. a second deceleration torque which should cause a deceleration higher than the first deceleration torque. Hydraulic pressure is already generated inside or in the brake system by the displacement of the brake pedal, which in this case is further increased when the deceleration torque is transferred from the electric machine to the brake system by controlling the motion of the pressure generator. . Since the driver is already operating the brake pedal with his foot at this time, he receives a tactile response from the hydraulic brake circuit. Such reactions are unpleasant and even lead to acoustic disturbance events. It is precisely in the low rpm range, where road noise and ambient noise are reduced, that acoustic events in the brake equipment or system can be perceived more clearly. In addition, it is possible that the pressure generator draws hydraulic medium for delivery from the main brake cylinder of the brake system to supply the friction brakes. As a result, the reaction force acting on the brake pedal is reduced, so that the brake pedal is unintentionally further depressed by the driver. This further overrun may possibly be detected by the brake system as an increased deceleration request, whereby a self-boosting of the requested deceleration torque is carried out, which is essentially what the driver desires. It leads to a deceleration torque higher than the deceleration torque to be applied.

The method according to the invention with the features of claim 1 has the advantage that the above-mentioned drawbacks are overcome. In simple terms, the method according to the invention eliminates unwanted acoustic events and effects on the brake pedal when the driver uses the one-pedal function and also actuates the brake pedal to preset the deceleration torque. It is possible to avoid the lack of reaction force to be applied.

The method according to the invention is characterized in that, above the limit rpm, the first deceleration torque requested by the accelerator pedal is reduced in dependence on the second deceleration torque requested by the brake pedal. The invention thus means that if a deceleration torque of the braking system is requested both by the brake pedal and by the accelerator pedal, the first deceleration torque preset, in particular by a fully released accelerator pedal, is actively reduced. It's like This achieves that the superimposition of deceleration torques in the brake system and the electric machine is reduced, in particular completely avoided. As soon as the limit rpm is undershot and a transition of the total deceleration torque from the electric machine to the brake system is introduced, at this moment only the deceleration torque required by actuation of the brake pedal, or at least the brake The deceleration torque required by the operation of the pedal is mainly acting. As a result, it is achieved that at the moment of the transition, the hydraulic medium is already stored in the hydraulic circuit, in particular in the hydraulic accumulator, due to the displacement of the brake pedal, and the deceleration torque continues to be produced exclusively by the electric machine. Realized is achieved. Now, when handover occurs, hydraulic medium is supplied to at least one of the friction brakes by means of a pressure generator, not from the main brake cylinder, but from the hydraulic accumulator. As a result, the development of hydraulic pressure in the hydraulic circuit does not affect the position of the brake pedal and the reaction force acting on the brake pedal is not reduced, so that the brake pedal is inconveniently pushed further by the driver. not be stepped on or stepped over by Thereby, on the one hand, self-boosting of the required deceleration torque is prevented and, on the other hand, no additional hydraulic volume needs to be displaced in order to achieve the required deceleration by means of the accelerator pedal. This avoids acoustic and tactile events from driving the pressure generator when hydraulic pressure is already present. This means that the hydraulic volume already introduced into the brake circuit by actuation of the brake pedal is used to transfer the deceleration torque of the electric machine to the brake system and thus to decelerate the vehicle to a standstill. A comfortable transition is guaranteed. In particular, the limit speed is preset according to the mechanical properties of the electric machine such that, above the limit speed, the electric machine can realize the required deceleration torque. Preferably, when determining the total deceleration torque, both the deceleration torques requested as a result of the brake request due to the release of the accelerator pedal and the operation of the brake pedal are considered so that the two deceleration torques are added to form the total deceleration torque. be done.

Preferably, the first deceleration torque is reduced by a presettable offset value. Thereby, the deceleration torque request by the accelerator pedal is not itself changed, but by the offset value, but the total deceleration request by the accelerator pedal is not completely changed, i.e. by a presettable offset value. It is reduced and compensated as applied to the electric machine and/or braking system. A favorable reduction is thereby ensured without intervening in the actual accelerator pedal control.

Further preferably, the first deceleration torque is reduced continuously, in particular in the form of a ramp, so that the driver does not perceive the reduction of the first deceleration torque and a gradual transition is guaranteed. there is

More preferably, the first deceleration torque is reduced in correspondence with the increase in the second deceleration torque. As a result, when the driver operates the brake pedal, the requested second deceleration torque does not cause the decrease in the first deceleration torque, or at least the driver does not feel anything from this compensation or the decrease in the first deceleration torque. Compensation to feel nothing or almost nothing is guaranteed.

Particularly preferably, the first deceleration torque is reduced only after the brake pedal operation activates the vacuum braking force booster of the system. The reduction of the first deceleration torque is thereby not carried out immediately upon actuation of the brake pedal, but only after the brake pedal has been operated to such an extent that the vacuum brake force booster of the brake system begins to work. be done. What can be said in this connection is the jump-in level of the vacuum brake booster. The jump-in level is not only the actuation of the brake pedal displacing the hydraulic piston in the main brake cylinder, but also the function of the vacuum braking force booster, which often starts only after a short movement stroke of the brake pedal. When it starts, it is reached. As soon as the function is activated, the hydraulic volume in the hydraulic circuit is increased more strongly or more hydraulic volume is displaced from the main brake cylinder, so that, in particular thereafter, the first deceleration torque is reduced. with the desired result. Controlling the operation of the pressure generator to deliver the total deceleration torque to the brake system or hydraulic braking system by actuation of the vacuum brake booster is not perceived as strongly by the driver and is considered acceptable.

More preferably, the first deceleration torque is reduced to zero so that the one-pedal function is finally stopped. Thereby, the total deceleration torque corresponds to the second deceleration torque obtained by the brake pedal. By reducing the first deceleration torque to zero, the aforementioned advantages of the method according to the invention are largely achieved.

If the brake pedal is released again by the driver before the rpm is undershot, so that the second deceleration torque is reduced or set to zero and the accelerator pedal continues to remain in the released position, Preferably, the first deceleration torque is increased again, in particular by reducing the offset value mentioned above. The driver removes his foot from the brake pedal before the aforementioned limit speed is reached, so that the brake pedal returns to its initial position and is thus released, and the second deceleration torque is thereby set to zero. When it is, due to the previous reduction of the first deceleration torque, the total deceleration torque will be set to zero if no further measures are taken. Since the driver, however, expects continued deceleration of the vehicle due to the aforementioned one-pedal function, therefore, according to this preferred development, in order to further decelerate the vehicle when the brake pedal is released: In addition, the reduction of the first deceleration torque is canceled in order to realize the one-pedal function. In this development, when increasing the first deceleration torque, the first deceleration torque and the second deceleration torque are preferably not added, but are preferably considered parallel to each other, so that in each case a higher Only one deceleration torque determines the total deceleration torque, or the total deceleration torque corresponds to the higher of the two required deceleration torques.

Preferably, the first deceleration torque is then increased up to the starting value at which the reduction started, in particular up to a preset maximum value for the first deceleration torque. This recreates the one-pedal function and the vehicle decelerates according to the actuation of the accelerator pedal. In order to allow the driver a comfortable and reliable deceleration by means of the one-pedal function only by means of the electric machine, the maximum value is set in particular according to the performance of the electric machine in generator operation and the application wishes of the vehicle manufacturer. In this case, the maximum value can be set and changed, for example, depending on the driving mode, eg sport driving mode or efficiency mode.

Preferably, the first deceleration torque is initially increased only to a maximum corresponding to the second deceleration torque upon release of the brake pedal.

Preferably, the first deceleration torque is increased beyond the second deceleration torque only after the second deceleration torque has fallen below a maximum value for the first deceleration torque. This is advantageous in that only then can the deceleration torque be realized by the accelerator pedal.

Preferably, the first deceleration torque is increased in accordance with the maximum possible deceleration torque increase of the electrical machine, so that the deceleration torque is realized partially or partially by means of a hydraulic brake system. , is avoided. Thereby, the acoustic and tactile events mentioned above are still avoided. As soon as the first deceleration torque exceeds the second deceleration torque, the total deceleration torque corresponds to the first deceleration torque, and the total deceleration torque corresponds to the first deceleration torque as soon as the brake pedal is fully released. Corresponds to deceleration torque. The total deceleration torque is then increased to the maximum value of the first deceleration torque, and the driver regains the one-pedal function.

A computer program according to the invention with the features of claim 12 is characterized by machine-readable instructions which, when run on one or more computers, cause the computer to perform the method according to the invention. This results in the advantages already mentioned above.

A machine-readable recording medium according to the invention with the features of claim 13 is characterized by a computer program according to the invention.

A control device according to the invention with the features of claim 14 is characterized in that it comprises a computer program according to the invention and/or a machine-readable recording medium according to the invention.

Further advantages and preferred features and combinations of features are evident especially from the foregoing description and claims. The present invention will be described in detail below with reference to the drawings.

1 is a simplified plan view of an advantageous motor vehicle; FIG. 1 is a graph illustrating an advantageous method of driving a motor vehicle; FIG. 5 is another diagram illustrating an advantageous development of the operating method; FIG.

FIG. 1 shows, in a simplified plan view, a motor vehicle 1 with an advantageous braking system 2 . As drive system, the motor vehicle 1 comprises, according to this embodiment, at least one electric machine 3 , which is connectable to drive wheels of the motor vehicle 1 . The electric machine 3 can be operated both as a motor and as a generator and exerts a braking or decelerating torque on the drive wheels during generator operation, so that the electric machine 3 belongs to the braking system 2 during generator operation, This makes it possible, for example, to fulfill or jointly fulfill a request for braking or deceleration of the driver of motor vehicle 1 . Optionally, motor vehicle 1 has, in addition to electric machine 3, an internal combustion engine as drive (not shown).

The brake system 2 further has a brake pedal 4 as a braking force requesting element or deceleration torque requesting element, and the brake pedal 4 can be operated by the driver. During operation, the brake pedal 4 can be displaced between a non-actuated or released initial position and a fully actuated or fully depressed end position. The brake pedal 4 is mechanically connected to the main brake cylinder 5 or to the hydraulic piston of the main brake cylinder 5 . The main brake cylinder 5, in response to actuation of the brake pedal, generates a hydraulic braking pressure which, according to the present embodiment, is supplied by a pressure distributor 6, for example an ESP system, having a plurality of controllable valves. is distributed by means of pressure distributors 6 to friction brakes 7 each associated with a wheel of the vehicle. In this case, a vacuum brake booster 9 is connected between the brake pedal 4 and the main brake cylinder 5, the vacuum brake booster 9 depending on the position of the brake pedal. It is possible to increase the force acting on the piston and thereby assist the driver when operating the braking system. Furthermore, the brake pedal 4 is assigned a sensor device 10 with a pedal travel sensor 11, which determines the current operating position of the brake pedal 4 or the current distance of the brake pedal 4 from its initial position. is monitored. The sensor device 10 is connected for this purpose to a control device 12 , which activates the brake system 2 .

The braking system 2 also has a controllable pressure generator 13, which in particular comprises a hydraulic pump driven or drivable by an electric motor. By controlling the operation of the pressure generator 13, the hydraulic pressure in the brake system with the pressure distributor 6 and the friction brake 7 is increased, so that the brake pedal 4, in particular, can be actuated without the driver's involvement. Even without it, a deceleration of the vehicle 1 can be caused. A pressure generator 13 is also connected to the control device 12 for this purpose.

Furthermore, motor vehicle 1 has an accelerator pedal 14 to which is assigned an accelerator-pedal sensor 15 , which is likewise connected to control device 12 , for monitoring the position of the accelerator-pedal. The accelerator pedal 14 can be displaced by the driver from a relaxed initial position to a fully depressed end position.

The control device 12 is designed to control the operation of the electric machine 3 as a function of the accelerator pedal position in order to generate an acceleration torque. Furthermore, control device 12 is designed to request a deceleration torque of brake system 2 as a function of accelerator pedal position 14 . For this purpose, the accelerator pedal 14 is operated with a so-called one-pedal function. In this case, the preset first deceleration torque is requested at least when the accelerator pedal 14 is in the relaxed initial position. Preferably, from a preset intermediate position of the accelerator pedal 14 between the end position and the released position, a deceleration torque is requested instead of the acceleration torque, the deceleration torque being applied when the accelerator pedal 14 is in the released position. increases until the maximum permitted deceleration torque is reached.

This gives the driver of motor vehicle 1 the ability to perform the hydraulic braking process with friction brake 7 both by actuating brake pedal 4 and by releasing accelerator pedal 14 . Similarly, it becomes possible to decelerate the vehicle 1 . The control device 12 is then designed such that at least the first deceleration torque requested by the accelerator pedal 14 is realized only by the generator operation of the electric machine 3 . As long as the current driving speed and/or the deceleration torque realizable by the electric machine 3 allow, the control device 12 additionally causes the second deceleration torque requested by the brake pedal 4 to be generated by the electric machine 3 only. is also formed. For this purpose, depending on the brake pedal position detected by sensor 11 , electric machine 3 is controlled in order to decelerate motor vehicle 1 . However, when the driver actuates the brake pedal 4 , the hydraulic medium is pumped into the brake circuit anyway, so that the hydraulic medium is in this case preferably hydraulically operated without actuating the friction brake 7 . is absorbed in the hydraulic accumulator 16 of the braking system.

With reference to FIG. 2, an advantageous method of driving the motor vehicle 1 will now be described in detail. The method is implemented in particular by a computer program stored in the controller 12 .

FIG. 2 shows, plotted over time t, the braking force _FB , which causes the deceleration torque of the motor vehicle 1, achievable by actuation of the accelerator and brake pedals. FIG. 2 starts from a driving situation in which the vehicle has a speed greater than zero. A first characteristic line K1 is entered in this graph, and the first characteristic line K1 indicates the first deceleration torque requested by the accelerator pedal 14. FIG. Furthermore, a characteristic line K2 is entered, which indicates the second deceleration torque requested by the brake pedal 4. FIG. A third characteristic line K3 shows the total deceleration torque generated by the electric machine 3 of the motor vehicle 1 as a function of the pedal actuation.

In the driving case where the driver first triggers or utilizes the one-pedal function of the accelerator pedal 14 by releasing the accelerator pedal 14 and then actuates the brake pedal 4, the following scenario occurs as shown in FIG.
First, the driver releases the accelerator pedal 14 at time _t1 (characteristic line K1). As a result, the first deceleration torque is requested. This deceleration torque is realized only by the electric machine 3 (characteristic line K3). The deceleration torque that can be set with the one-pedal function is limited in particular to a maximum value K1 _max which is less than the maximum deceleration torque that can be provided by the electric machine 3 . If the driver only releases the accelerator pedal 14, the motor vehicle 1 is thereby decelerated to a standstill with the maximum achievable deceleration torque K1 _max .

Now, if the driver additionally actuates the brake pedal 4 at a later point in time _t2 (characteristic line K2), for example in order to bring the motor vehicle to a standstill more quickly, the total deceleration torque is Depending on the second deceleration torque required by the operation, the second deceleration torque is in particular added to the first deceleration torque in order to determine the total deceleration torque, which is increased in particular above the maximum value. be.

As soon as the brake pedal 4 is operated to such an extent that the vacuum type braking force booster 9 starts assisting braking force generation (jump-in level), the first deceleration torque obtained by the accelerator pedal 14 becomes the offset value. It is continuously reduced by addition until it is fully compensated at time _t3 . As a result, the total deceleration torque (characteristic line K3) is determined only by the second deceleration torque required by operating the brake pedal (characteristic line K2).

Due to the total deceleration required, as the driving speed of the vehicle 1 decreases, the rpm of the electric machine 3 also decreases. At time _{t4 ,} the generator torque can no longer be maintained by electric machine 3, or can no longer be maintained efficiently. The limit speed, which determines this instant, results from the mechanical properties of the electric machine 3 itself and is therefore dependent on the electric machine 3 used. As soon as the limit speed is reached, here at time _t4 , the control device 12 activates the brake system 2 so that the total retarding torque hitherto provided by the electric machine 3 is now fully hydraulic service brake or brake. It controls the operation so that it is transitioned to the device. For this purpose, the deceleration torque of the electric machine 3 is reduced at a preset speed and the deceleration torque that can be generated by the friction brake 7 is increased, in particular at the same speed. For this purpose, a fourth characteristic line K4 is entered in FIG. The deceleration torque applied increases from time _t4 until the total deceleration torque required is reached. At the same time, the deceleration torque due to the generator (characteristic line K3) decreases, so that the total deceleration torque remains constant until the vehicle 1 reaches a standstill.

Since the first deceleration torque has previously been reduced to zero using an offset value (time t ₃ ), the total deceleration torque at time t ₄ is equal to the second deceleration torque requested by the brake pedal 4 . Equivalent to. In this state, the brake pedal 4 has already been actuated and the hydraulic medium has been displaced or displaced into the hydraulic circuit by the user's actuation, so that now, in order to deliver the deceleration torque to the brake system: In order to generate the friction braking force (characteristic line K4), the pressure generator 13 draws the hydraulic volume already present in the hydraulic circuit, in particular from the hydraulic accumulator 16, and applies this hydraulic volume to the friction brake 7 under pressure. Appropriately applied by the distributor 6, the operation is controlled so that the required deceleration torque can be realized by friction braking. Thereby, the brake pedal remains at the pedal position preset by the driver, tactile feedback at the brake pedal is avoided, and Unintentional and disturbing noise due to hydraulic pump operation is avoided. Otherwise, the hydraulic pump would provide an additional hydraulic volume to the main brake cylinder and/or to the main brake cylinder and/or the hydraulic pressure so that it can also compensate for the otherwise unreduced first deceleration torque. It will need to be removed from the hydraulic fluid container.

FIG. 3 shows an advantageous development of the above-described method for a series of operating cases, in which the driver has the option of reaching a standstill before reaching a standstill and in particular before reaching the limit speed of the electric machine 3 . Then, at time _t5 , the foot is removed from the brake pedal 4 or the brake pedal 4 is released. At the following instant _t6 , the second deceleration torque is then reduced to zero. As a result, according to the method described above, the deceleration torque will now no longer be required and the vehicle 1 will come to a stop.

However, in order to provide the driver with the one-pedal function that he would expect during driving, the first deceleration torque reduction is therefore preferably canceled by the release of the brake pedal 4. . In doing so, in particular by releasing the brake pedal 4, the total deceleration torque is determined by comparing the two required deceleration torques with each other and determining the respective higher deceleration torque of the first and second deceleration torques. , is modified to be used or determined as the total deceleration torque. From time _t5 onwards, the first deceleration torque is first reduced, as indicated by characteristic line I, to the canceled deceleration torque of the brake pedal without the need to pump further hydraulic medium into the hydraulic circuit. Canceled quickly to compensate. It is then taken into account how quickly the deceleration torque that can be provided by the electric machine 3 can be increased. As long as this is not exceeded, no additional pumping of hydraulic medium in the brake circuit is necessary. Correspondingly, the first deceleration torque is further guided according to characteristic line II up to a maximum value K1 _max , so that the total deceleration torque is still only provided by electric machine 3 in accordance with the brake request of the one-pedal function. The motor vehicle 1 thereby subsequently decelerates for the driver in accordance with the expected one-pedal function, possibly even to a standstill.

REFERENCE SIGNS LIST 1 motor vehicle 2 brake system 3 electric machine 4 brake pedal 5 main brake cylinder 6 pressure distributor 7 friction brake 9 vacuum braking force booster 10 sensor device 11 pedal stroke sensor 12 control device 13 pressure generator 14 accelerator pedal 15 accelerator pedal sensor 16 hydraulic accumulator _FB braking force I characteristic line II characteristic line K1 first characteristic line K1 _max first deceleration torque maximum value K2 characteristic line K3 third characteristic line K4 fourth characteristic line t time t ₁ Time t _2nd time t _3rd time t _4th time t _5th time t _6th time

Claims (14)

A method of driving a motor vehicle (1), said motor vehicle (1) comprising:
A brake system (2),
a hydraulic braking device comprising a controllable pressure generator (13) and at least one friction brake (7) hydraulically connectable to said pressure generator (13);
an electrical machine (3) operable as a generator to slow down the vehicle (1);
a braking system (2) comprising
an accelerator pedal (14);
a brake pedal (4);
deceleration torque of the brake system (2) can be requested by operating the brake pedal (4) and releasing the accelerator pedal (14), and the brake system (1) operates on the accelerator pedal above a presettable limit speed of said electric machine (3) depending on the first deceleration torque requested by (14) and the second deceleration torque requested by said brake pedal (4). At speed, the required total deceleration torque is realized only by the electric machine (3), and when the speed is below the limit speed, the required total deceleration torque is transferred from the electric machine (3) to the braking device. The operation is controlled so as to be transitioned by the operation control of the pressure generator (13),
in the method
above the limit speed, reducing the first deceleration torque requested by the accelerator pedal (14) in accordance with the second deceleration torque requested by the brake pedal (4);
A method of driving a car, characterized by: 2. Method according to claim 1, characterized in that the first deceleration torque is reduced by a presettable offset value. 3. A method as claimed in claim 1 or 2, characterized in that the first deceleration torque is continuously reduced. 4. A method as claimed in any one of the preceding claims, characterized in that the first deceleration torque is reduced correspondingly to an increase in the second deceleration torque. 5. Any one of claims 1 to 4, characterized in that the first deceleration torque is reduced only after a vacuum booster (9) of the brake system (2) is actuated by actuation of the brake pedal. or the method according to item 1. 6. Method according to any one of claims 1 to 5, characterized in that the first deceleration torque is reduced to zero. If the brake pedal (4) is released before falling below the limit rpm and the accelerator pedal (14) is maintained in the released accelerator pedal position, the first deceleration torque is applied, in particular to the offset 7. A method according to any one of claims 1 to 6, characterized by increasing by decreasing values. 8. Method according to claim 7, characterized in that the first deceleration torque is increased up to an initial value at which the reduction started, in particular up to a preset maximum value for the first deceleration torque. 9. According to the release of the brake pedal (4), the first deceleration torque is initially only increased to correspond at most to the second deceleration torque. A method according to any one of 10. According to any one of the preceding claims, characterized in that the first deceleration torque is increased beyond the second deceleration torque only after the second deceleration torque has fallen below a limit value. the method of. 11. Method according to claim 10, characterized in that the first deceleration torque is increased according to the maximum possible deceleration torque increase of the electric machine (3). A computer program comprising machine-readable instructions which, when run on one or more computers, causes said computer to perform the method of any one of claims 1 to 11. A machine-readable recording medium comprising a computer program according to claim 12. A computer, in particular a control device, comprising a computer program according to claim 12 and/or a machine-readable recording medium according to claim 13.

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