Method for operating drive train of motor vehicle

Abstract

The invention relates to a method for operating a drive train of a motor vehicle, in which a coasting mode is presented by deactivating and deactivating an internal combustion engine in the drive train via an intermediate starting element from at least one drive wheel during the travel of the motor vehicle. In order to end the coasting mode, the starting of the internal combustion engine is carried out as a towed starting, and the starting element transmits torque between the internal combustion engine and the at least one drive wheel in the range of the towed starting and thus tows the internal combustion engine via the at least one drive wheel. According to the invention, during the execution of a towed start, a slip of at least one drive wheel occurring when towing the internal combustion engine is ascertained, and a locking remark is generated as a function of the ascertained slip, during a current driving cycle of the motor vehicle, the presence of the lock notes is used to inhibit subsequent towed activations for respectively ending the subsequent freewheeling run.

Description

TECHNICAL FIELD

[0001] The invention relates to a method for operating a drive train of a motor vehicle, wherein an inertial coasting operation is presented by separating and switching off the internal combustion engine from at least one drive wheel in the drive train via an intermediate starting element during a motor vehicle drive, wherein a start of the internal combustion engine is carried out as a drag start for ending the inertial coasting operation, the starting element carries out a torque transmission between the internal combustion engine and the at least one drive wheel and thus drags the internal combustion engine via the at least one drive wheel in the scope of the drag start, and wherein a slip occurring when the at least one drive wheel drags the internal combustion engine is ascertained when carrying out the drag start. Furthermore, the invention also relates to a controller, a computer program product and a data carrier. BACKGROUND

[0002] It is common in motor vehicle drive trains with internal combustion engines that a starting element is provided between the respective internal combustion engine and the respective drive wheel, by means of which the connection between the respective internal combustion engine and the respective drive wheel can be established or separated depending on the driving situation to be presented. Such a starting element can exist here, for example, as a starting clutch or also as a hydrodynamic torque converter. In motor vehicle drive trains it is also possible to implement a so-called inertial coasting operation in which a free roll of the respective motor vehicle can be achieved when no propulsion of the motor vehicle is presented by the internal combustion engine. For this purpose, the drive separation of the internal combustion engine from the drive wheel is carried out via an intermediate starting element and the internal combustion engine is subsequently switched off in order to save fuel during the course of the inertial coasting operation. In order to end the inertial coasting operation, the internal combustion engine is started again, wherein this is carried out as an alternative to the start via a starter motor, partly also by dragging the internal combustion engine via the drive wheel. For this purpose, it is necessary to establish the drive connection between the internal combustion engine and the drive wheel at least partially via the starting element.

[0003] A method for operating a motor vehicle drive train is known from DE 10 2015 016 971 B4, in which method an internal combustion engine can be drivingly connected to the drive wheels of a drive axle via an intermediate starting element in the form of a shift clutch. In the motor vehicle drive train, a coasting operation can be implemented in such a way that the internal combustion engine is disconnected from the drive wheels of the drive axle by opening of the shift clutch and is then switched off. In order to end the coasting operation, the internal combustion engine can then be started, on the one hand, in a first operating mode via an electric machine which is assigned to the internal combustion engine as a starter. But on the other hand, a drag start can also be implemented in the scope of a second operating mode, in which the shift clutch allows a torque transmission between the internal combustion engine and the drive wheels by at least partial closure and thus a drag of the internal combustion engine by the drive wheels occurs. In order to keep the influence on the driving operation of the motor vehicle as small as possible in the event of such a drag, a slip occurring at the drive wheels is detected when the drag start is carried out, wherein, from the moment when a relevant limit value is exceeded, the electric machine is additionally used to start the internal combustion engine and also to drive the drive wheels in order to reduce the slip occurring. SUMMARY

[0004] Based on the aforementioned prior art, it is now the task of the present application to improve safety when operating a motor vehicle drive train which can be operated in a coasting operation.

[0005] This task is solved from a method-technical point of view with the preamble of claim 1 and in conjunction with the characterizing part of the features. The subsequent dependent claims each specify an advantageous improvement of the application. Furthermore, a controller which can be used to carry out the aforementioned method is the subject matter of claims 12 and 13. Furthermore, claim 14 relates to a computer program product and claim 15 relates to a data carrier.

[0006] According to the application, in the method for operating a motor vehicle drive train according to the application, a coasting operation is represented by disconnecting the internal combustion engine from at least one drive wheel via an intermediate starting element in the motor vehicle drive train during a driving operation of the motor vehicle and switching off the internal combustion engine. In order to end the coasting operation, the starting of the internal combustion engine is carried out as a drag start, in the scope of which the starting element implements a torque transmission between the internal combustion engine and the at least one drive wheel and thus drags the internal combustion engine via the at least one drive wheel. Here, a slip occurring at the at least one drive wheel when dragging the internal combustion engine is detected when the drag start is carried out.

[0007] At the start of the method according to the application, the drive train of the motor vehicle is initially operated in a coasting mode in which the internal combustion engine provided in the drive train is driven apart from the at least one drive wheel and is then switched off. In the sense of the application, the "driven apart" of the internal combustion engine from the at least one drive wheel here means that no torque can be transmitted between the internal combustion engine and the at least one drive wheel after the separation, so that the internal combustion engine and the at least one drive wheel can perform a rotational movement independently of one another. Here, this driven apart is carried out in the context of the coasting mode in order to switch off the internal combustion engine, that is to say to stop the internal combustion engine, during the travel of the motor vehicle and after the separation, and to enable the motor vehicle to continue to travel by enabling the at least one drive wheel to rotate freely without being coupled to the internal combustion engine.

[0008] The driven apart of the motor vehicle from the at least one drive wheel is carried out in the context of the coasting mode via a starting element which is arranged in the power flow between the internal combustion engine and the at least one drive wheel in the drive train and which, depending on its actuation state, either carries out the driven apart or enables the transmission of torque between the internal combustion engine and the at least one drive wheel. In particular, this starting element relates to a friction clutch which, in a fully open state, separates the internal combustion engine from the at least one drive wheel, while the friction clutch, from at least a partially closed state, enables the transmission of torque between the internal combustion engine and the at least one drive wheel.

[0009] The at least one drive wheel can be driven in the drive train of the motor vehicle via the internal combustion engine, for which a drive connection between the internal combustion engine and the at least one drive wheel is established via an intermediate starting element and thus a transmission of torque from the internal combustion engine to the at least one drive wheel is present. Correspondingly, the at least one drive wheel is assigned to the internal combustion engine in the drive train. Preferably, however, the internal combustion engine is assigned a plurality of drive wheels, wherein the drive wheels are assigned to the internal combustion engine in pairs, in particular here by making pairs of associated drive wheels part of each drive axle of the motor vehicle.

[0010] Within the scope of the method according to the application, the inertial glide operation (that is to say the free coasting of the motor vehicle) is ended by starting the internal combustion engine in a drag start. This drag start takes place here by means of the internal combustion engine being dragged via the at least one drive wheel, for which purpose the intermediate starting element effects a torque transmission between the internal combustion engine and the at least one drive wheel during the travel of the motor vehicle. In the case of the starting element being designed as a friction clutch, this friction clutch is at least partially closed for this purpose. By means of this torque transmission, the at least one drive wheel causes a rotational movement of the internal combustion engine, so that the internal combustion engine can be started above at least the necessary idle speed. Particularly preferably, this drag start takes place here completely without the aid of a starter motor assigned to the internal combustion engine, so that the starting of the internal combustion engine takes place purely by means of the drag in the scope of the drag start for ending the inertial glide operation. However, within the scope of the application, the starting of the internal combustion engine is also effected with the aid of the starter motor in the scope of the drag start if necessary, for example when the respective rotational movement via the at least one drive wheel cannot produce a sufficiently high rotational speed of the internal combustion engine.

[0011] In the course of the execution of the drag start, the slip occurring at the at least one drive wheel when the internal combustion engine is being dragged is therefore determined. The at least one drive wheel thus has a certain slip when the internal combustion engine is being dragged in the course of the drag start.

[0012] The technical teaching now contained in the application is that a lock note is generated in dependence on the slip occurring ascertained, with the presence of the lock note inhibiting a subsequent drag start for ending a subsequent inertial glide operation, respectively, in the course of the current travel phase of the motor vehicle. In other words, a lock note is output in dependence on the slip occurring at the at least one drive wheel when the drag start is executed by means of the internal combustion engine being dragged. If this lock note is active, the result is that a subsequent inertial glide operation in the course of the current travel phase of the motor vehicle cannot be ended by means of a subsequent drag start, respectively, by means of the respective inertial glide operation.

[0013] This operation of the drive train of the motor vehicle has the advantage that the safety of the motor vehicle can thereby be improved at the end of the inertial glide operation. It is thus possible to avoid situations which endanger the safety of the journey and also to avoid high loads of components of the drive train at the end of one or more subsequent inertial glide operations in the course of the current journey by producing the lock note. The influence of the drag engine can be detected by the knowledge of the occurring slip when a drag start is carried out. If the drag start leads to a high slip, it can be concluded from this that a subsequent drag start also leads to a similar high slip in the course of the current journey. In order to avoid this, in the context of the method according to the application, a subsequent drag start is not permitted in the course of the current journey when the lock note is present to end the respective subsequent inertial glide operation. In addition to improving the safety of the motor vehicle and preventing overloading of the intermediate starting element in particular, the influence of the reduced driving comfort when the drag engine is thus also avoided.

[0014] A subsequent drag start of the internal combustion engine is prohibited in the course of the current journey of the motor vehicle when the lock note is present. Here, "journey" means the time range within which the ignition of the motor vehicle is switched on. In particular, the lock note stored at this point in time is deleted when the ignition is switched off, so that no lock note is stored when the next journey is started by switching on the ignition.

[0015] In particular, the lock note is produced when the known occurring slip exceeds a limit value. In the context of the method according to the application, the known slip is therefore compared with a predetermined limit value, which defines the still permissible slip at at least one drive wheel when a drag start is carried out. If the known slip is above this limit value, the lock note is produced.

[0016] According to an embodiment of the application, the produced lock note is again eliminated when at least one condition is present, after which the prohibition of the subsequent drag start is cancelled. The prohibition of the subsequent drag start is thus cancelled in addition to the end of the current journey when at least one condition is met. The at least one condition therefore relates to an increase in the vehicle mass of the motor vehicle which occurs in the course of the current journey. Since an increase in the vehicle mass which occurs in this period of time usually leads to the fact that the slip of at least one drive wheel which occurs in a subsequent drag of the internal combustion engine is lower in this subsequent drag, the prohibition of the subsequent drag start can no longer be reasonable. When the motor vehicle is designed as a utility vehicle, the vehicle mass can change, for example, by a semi-trailer being coupled during this period of time or the utility vehicle being loaded during this period of time, which can be identified by axle load sensors, the state of the trailer and / or a mass calculation.

[0017] According to one design option of the application, in the context of a drag start and before the torque transmission between the combustion engine and the at least one drive wheel is carried out, it is first checked whether at least one interruption criterion for interrupting the drag start is present. The drag start is interrupted if the at least one interruption criterion is present and continued if the at least one interruption criterion is not present. In this way, further criteria against carrying out a combustion engine start in the context of a drag start can be taken into account in an advantageous manner.

[0018] The load, in particular the thermal load, of the starting element beyond a load limit is thus identified as an interruption criterion, in particular. Since a high load of the starting element is already present when a drag start is carried out, an overload of the starting element and thus a subsequent safety-endangering state can result. By interrupting the drag start on the basis of a defined load limit, preferably a temperature limit, of the starting element, such an overload can be reliably ruled out. As an alternative to this, but preferably in addition to this, a vehicle weight of the motor vehicle below a weight limit is identified as an interruption criterion. In this way, the drag start is also interrupted when the motor vehicle has too little weight, for example due to an excessively low load. It is particularly preferred in general that, in the context of a drag start and before the torque transmission is carried out, it is checked whether one of the two aforementioned interruption criteria is present.

[0019] According to one design option of the application, the occurring slip is ascertained by observing a deviation of the rotational speed of the at least one drive wheel from the rotational speed of the at least one non-drive wheel. In this way, the occurrence of a slip on the at least one drive wheel can be inferred in a reliable manner.

[0020] A further embodiment of the application is that the lock note is also generated when an active intervention of at least one driving stability assistance system is detected during the execution of the drag start. Since it is thereby also identified whether a driving safety-endangering state occurs during the dragging of the combustion engine, which is prevented by the active intervention of the at least one driving stability assistance system, the at least one driving stability assistance system here relates to an ABS system or an ESP system. Preferably, the active intervention of the at least one driving stability assistance system during the execution of the drag start is detected when the intervention time of the at least one driving stability assistance system exceeds a limit value. Thus, only a decisive intervention of the driving stability assistance system leads to the generation of the lock note.

[0021] Preferably, the drag start is interrupted with the generation of the lock note, whereby a safety-endangering driving situation is already avoided in the current coasting operation by the interruption.

[0022] According to a further design option of the application, during the course of the current driving cycle, in the presence of a locking note and / or in the event of an interruption to the coasting run, the subsequent starting of the internal combustion engine is carried out as a start-up start, in the context of which the internal combustion engine is started via the starter and with the internal combustion engine being decoupled from the at least one drive wheel. The starting of the internal combustion engine via the starter is thus achieved in the presence of a locking note and / or in the event of an interruption to the current coasting run, and the respective coasting run can thus be ended in a safe manner.

[0023] Furthermore, the subject matter of the application is also a controller which is provided here for the purpose of promoting the execution of a coasting run in the drive train of a motor vehicle and for this purpose causes the internal combustion engine to be decoupled from the drive of the at least one drive wheel via an intermediate starting element and, immediately thereafter, causes the internal combustion engine to be switched off. The controller is also configured for the purpose of promoting the starting of the internal combustion engine in a drag start in order to end a coasting run, the starting element carrying out the torque transmission between the internal combustion engine and the at least one drive wheel in the context of the drag start and the at least one drive wheel thus dragging the internal combustion engine. Furthermore, the controller is also provided for the purpose of detecting a slip occurring in the at least one drive wheel when it is dragging the internal combustion engine when a drag start is being carried out and generating a locking note in dependence on the detected occurring slip, the presence of the locking note inhibiting a subsequent drag start for the purpose of ending a subsequent coasting run during the course of the current driving cycle. The controller is furthermore particularly preferably provided for the purpose of implementing one or more of the aforementioned variants of the method.

[0024] The method according to the application can also be embodied as a computer program product which, when the computer program product is run on a processor, for example the processor of the aforementioned controller, instructs the processor in software to carry out the method steps of the associated subject matter of the application. In this interrelationship, a computer-readable medium is also subject matter of the application, on which the aforementioned computer program product is stored in a retrievable manner. BRIEF DESCRIPTION OF DRAWINGS

[0025] Advantageous embodiments of the application which will be explained in the following are illustrated in the drawings. In the drawings:

[0026] Figure 1 a schematic view of a motor vehicle is shown; and

[0027] Figure 2 a flow chart of a method according to the application for operating Figure 1 a drive train of a motor vehicle is shown. DETAILED DESCRIPTION

[0028] from Figure 1A schematic view of a motor vehicle 1, which relates in particular to a commercial vehicle, can be seen. The motor vehicle 1 comprises a drive train 2 in which an internal combustion engine 3 is arranged. A starter 4 is provided for the internal combustion engine 3, which preferably relates to an electric starter in the form of an electric machine and by means of which the internal combustion engine 3 can be started in the range of a starter-type start.

[0029] On the driven side, the internal combustion engine 3 can also be drivingly connected via an intermediate start-up element 5 to a transmission input of a motor vehicle transmission 6 arranged downstream, by means of which the drive torque provided by the internal combustion engine 3 can be transmitted via the motor vehicle transmission at different transmission ratios. The start-up element 5 is designed here in particular as a start clutch. A differential 7 is arranged downstream of the motor vehicle transmission 6 on the driven side, which distributes the drive torque transmitted via the motor vehicle transmission 6 to the two drive wheels 8 and 9 of a drive axle 10 of the motor vehicle 1 as a transverse differential. In addition to the drive axle 10, the motor vehicle 1 also has a non-driven axle 11 with two non-driven wheels 12 and 13.

[0030] In the motor vehicle 1, a freewheeling operation can be implemented in a manner known in principle to the person skilled in the art, i.e. during a journey of the motor vehicle 1, the internal combustion engine 3 is drivingly decoupled in the drive train 2 via the start-up element 5 from the motor vehicle transmission 6 and thus also from the two drive wheels 8 and 9. The internal combustion engine 3 is switched off after this decoupling in order to reduce the fuel consumption in the motor vehicle 1 in the range of the freewheeling operation. As a result of the driving decoupling of the two drive wheels 8 and 9 from the internal combustion engine 3, the motor vehicle 1 can be coasted freely during the freewheeling operation.

[0031] In the presence of a freewheeling operation and in the course of an ongoing journey of the motor vehicle 1, the drive train 2 is operated in the range of a method according to the application, the flow chart of which is shown in Figure 2 and is explained in the following text. The method is executed here by a controller 14, which relates to a transmission controller. The controller 14 controls the start-up element 5 and the motor vehicle transmission 6 and communicates in a data bus system with an engine controller 15, which controls the internal combustion engine 3 and the starter 4.

[0032] The start of the method according to the application is the recognition of the presence of a freewheeling operation in a first step S1 of the method. Then, in a second step S2 following step S1, it is enquired whether a request for the end of the current freewheeling operation is present. If this is negative, there is a jump back to step S1 and the freewheeling operation is continued, wherein the transition to step S2 is preferably renewed after the expiry of a defined time window.

[0033] If, on the other hand, a request for ending the current overrun mode is identified in step S2, it is then checked in step S3 whether the end of the overrun mode should take place in the range of a drag start, in which the starting element 5 is closed at least partially to effect torque transmission between the internal combustion engine 3 and the motor vehicle transmission 6, in turn the drive wheels 8 and 9, so that the internal combustion engine 3 can be dragged and started via the drive wheels 8 and 9. If no drag start is requested in step S3, a transition is made to step S4, in which the internal combustion engine 3 is started via the starter 4 in the range of a starter start, with the internal combustion engine 3 being separated from the drive wheels 8 and 9 as before by the starting element 5.

[0034] If, on the other hand, a drag start is requested, step S3 is followed by a further step S5, in which it is asked whether a drag start is permitted or whether the vehicle mass of the motor vehicle 1 has changed in the range of the current driving cycle of the motor vehicle 1. If one of these two criteria is fulfilled, a transition is made to step S6, in which a transition is made to step S4 and, in correspondence therewith, the starting of the internal combustion engine 3 is carried out as a starter start, during which no drag start is permitted and at the same time the vehicle mass has not changed.

[0035] In step S6, only the lock note set for the drag start as necessary is cancelled and a transition is then made to step S7. In step S7, it is checked whether an interruption criterion for interrupting the drag start is present. To this end, it is asked, on the one hand, whether the current thermal load of the starting element 5 is below a defined load limit and whether the vehicle mass of the motor vehicle is above a predetermined weight limit. If the current thermal load is below the load limit and the vehicle mass at the same time exceeds the predetermined weight limit, a transition is made to step S8, whereas otherwise it is identified that the interruption criterion is present and the drag start is interrupted. As a result of this interruption, a transition is made back to step S4 and the starting of the internal combustion engine 3 is thus carried out as a starter start.

[0036] In the transition to step S8, the drag start of the internal combustion engine 3 is introduced by closing the starting element 5, wherein, on the one hand, a slip occurring at the drive wheels 8 and 9, respectively, is ascertained. This slip is ascertained here by observing the deviation of the rotational speed of the drive wheels 8 and 9 from the rotational speed of the non-driven wheels 12 and 13. If the slip occurring at the drive wheels 8 and 9 here exceeds a limit value, a transition is made to step S9. Furthermore, a transition to step S9 takes place even if the slip occurring is below the limit value when it is detected that a driving stability assistance system of the motor vehicle 1 actively intervenes for a defined duration. The driving stability assistance system is here, for example, an ESP system. Thus, for the transition from step S8 to step S9, either the slip occurring must exceed the limit value or the active intervention of the driving stability system must take place for a defined duration.

[0037] The lock note is set in step S9 and the method according to the application is then returned to step S5. If at the time a conclusion of the inertial glide operation is to be carried out, the return to step S5 leads to the set lock note being recognized as lacking the permission for a drag start and to a transition to step S4. Subsequently, the transition from step S8 to step S9 also leads to an interruption of the current drag start, in which a start of the internal combustion engine 3 takes place in the range of a starter start and a conclusion of the inertial glide operation takes place during the internal combustion engine start.

[0038] If, on the other hand, neither a slip exceeding the limit value nor a sufficiently long intervention of the driving stability system is recognized in step S8, the internal combustion engine 3 is dragged by a complete drag start in the range of step S10 following step S8. After the drag has been carried out, the method according to the application is ended with step S11 being reached, to which the transition is made from step S4 after a starter start has been carried out.

[0039] If a subsequent inertial glide operation is carried out in the course of the ongoing journey of the motor vehicle 1, the lock note set in step S9 leads to a prohibition of a subsequent drag start when the method according to the application is carried out in step S5. The set lock note leads to a transition to step S4 in step S5. If, however, an increase in the vehicle mass takes place in the course of the ongoing journey, for example as a result of loading the motor vehicle 1, coupling on a trailer or coupling on a semitrailer, a transition to step S6, in which the lock note is cancelled, takes place even in the presence of the lock note. If, however, the increase in the vehicle mass is insufficient or the load on the starting element 5 is already too high, the check in step S7 still leads to an interruption of the subsequent drag start.

[0040] The safety of the operation of the drive train, which can be operated in the inertial glide operation, can be improved by means of the method according to the application.

[0041] List of reference signs

[0042] 1 motor vehicle

[0043] 2 drive train

[0044] 3 internal combustion engine

[0045] 4 starter

[0046] 5 starting element

[0047] 6 motor vehicle transmission

[0048] 7 differential

[0049] 8 drive wheel

[0050] 9 drive wheel

[0051] 10 drive axle

[0052] 11 vehicle axle

[0053] 12 vehicle wheel

[0054] 13 vehicle wheel

[0055] 14 controller

[0056] 15 engine controller

[0057] S1 to S11 individual steps

Claims

1. A method for operating a drive system (2) of a motor vehicle (1), wherein, During the driving of the motor vehicle (1), the internal combustion engine (3) is driven to disengage and stop from at least one drive wheel (8, 9) in the drive system (2) via an intermediate starting element (5) to achieve inertial coasting operation, wherein the starting of the internal combustion engine (3) is performed as a towing start to end the inertial coasting operation, the starting element (5) performs torque transmission between the internal combustion engine (3) and the at least one drive wheel (8, 9) within the range of the towing start and thus tows the internal combustion engine (3) via the at least one drive wheel (8, 9), and wherein slippage of the at least one drive wheel (8, 9) in towing the internal combustion engine (3) is known when the towing start is performed, characterized in that a locking note is generated based on the known slippage, and the presence of the locking note is used to prohibit subsequent towing starts for ending subsequent inertial coasting operations during the current driving cycle of the motor vehicle (1).

2. The method according to claim 1, characterized in that, The locking note is generated when the known slip exceeds the boundary value.

3. The method according to claim 1 or 2, characterized in that, If at least one condition is met, the generated lock note is removed, and then the prohibition on subsequent drag-and-drop startups is lifted.

4. The method according to claim 3, characterized in that, The at least one condition exists when the vehicle mass of the motor vehicle (1) increases during the current driving cycle.

5. The method according to any one of the preceding claims, characterized in that, Within the range of the towing start and before the torque transmission between the internal combustion engine (3) and the at least one drive wheel (8, 9) is performed, it is first checked whether there is at least one interruption criterion for interrupting the towing start, wherein the towing start is interrupted when the at least one interruption criterion is present, and the towing start continues when the at least one interruption criterion is absent.

6. The method according to claim 5, characterized in that, The load, especially the thermal load, of the starting element (5) is identified as exceeding the load boundary as an interruption criterion.

7. The method according to claim 5 or 6, characterized in that, The vehicle weight of the motor vehicle (1) being below the weight boundary is identified as an interruption criterion.

8. The method according to any one of the preceding claims, characterized in that, The slippage is determined by observing the deviation between the rotational speed of at least one drive wheel (8, 9) and the rotational speed of at least one non-drive wheel (12, 13).

9. The method according to any one of the preceding claims, characterized in that, The lockout note is also generated when active intervention of at least one driving stability assist system is detected during the execution of the tow start.

10. The method according to any one of the preceding claims, characterized in that, The drag-and-drop startup is interrupted by generating a lock note.

11. The method according to any one of the preceding claims, characterized in that, During the current driving cycle, in the presence of the locking note and / or when the towing start is interrupted, the start of the internal combustion engine (3) is then performed as a start-up start, within the range of the start-up start via the starter (4) and when the internal combustion engine (3) is disengaged from the at least one drive wheel (8, 9).

12. A controller (14) configured to: induce coasting in the drive system (2) of the motor vehicle (1) and thereby cause the internal combustion engine (3) to disengage from at least one drive wheel (8, 9) via an intermediate starting element (5) and subsequently cause the internal combustion engine (3) to shut down, wherein, The controller (14) is configured to: induce the start of the internal combustion engine (3) in a towing start to end the coasting operation, the starting element (5) performing torque transmission between the internal combustion engine (3) and the at least one drive wheel (8, 9) within the range of the towing start and thus the at least one drive wheel (8, 9) towing the internal combustion engine (3), and wherein the controller (14) is configured to: detect slippage of the at least one drive wheel (8, 9) while towing the internal combustion engine (3) during the execution of the towing start and generate a locking note based on the detected slippage, thereby prohibiting subsequent towing starts for ending subsequent coasting operations during the current driving cycle of the vehicle (1) by means of the presence of the locking note.

13. The controller (14) of claim 12, further configured to: perform the method according to any one or more of claims 2 to 11.

14. A computer program product for the controller (14) according to claim 12 or 13, wherein the computer program product is capable of performing the method according to any one or more of claims 1 to 11, wherein, The routines for the drive system (2) used to run the motor vehicle (1) are implemented by the corresponding control instructions stored in the software.

15. A data carrier having the computer program product according to claim 14.

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