阅读说明：本技术 用于运行用于机动车的动力传动设备的方法及相应的动力传动设备 (Method for operating a drive train for a motor vehicle and corresponding drive train ) 是由 M·D·霍尔 G·席德特 A·泽伊尔 于 2020-05-13 设计创作，主要内容包括：本发明涉及一种用于运行用于机动车(1)的动力传动设备(2)的方法,其中,动力传动设备(2)具有至少一个内燃机(4)、与内燃机(4)在驱动技术上联接或能联接的电机(5)以及起动离合器(7),内燃机(4)和电机(5)通过起动离合器在驱动技术上联接到动力传动设备(2)的输出轴(6)上。在此规定,在动力传动设备(2)的起动运行模式中,内燃机(4)在起动离合器(7)脱开的情况下以不点火的方式运行并且借助于电机(5)拖曳到起动转速上,起动转速高于内燃机(4)的怠速转速,其中,在达到起动转速之后,内燃机(4)以点火的方式运行并且起动离合器(7)接合。此外,本发明涉及一种用于机动车(1)的动力传动设备(5)。(The invention relates to a method for operating a drive train (2) for a motor vehicle (1), wherein the drive train (2) has at least one internal combustion engine (4), an electric machine (5) which is or can be coupled to the internal combustion engine (4) in terms of drive, and a starting clutch (7), by means of which the internal combustion engine (4) and the electric machine (5) are coupled in terms of drive to an output shaft (6) of the drive train (2). In a starting mode of operation of the drive train (2), the internal combustion engine (4) is operated without ignition with the starting clutch (7) disengaged and is pulled by means of the electric machine (5) to a starting speed which is higher than the idling speed of the internal combustion engine (4), wherein, after the starting speed is reached, the internal combustion engine (4) is operated with ignition and the starting clutch (7) is engaged. The invention further relates to a drive train (5) for a motor vehicle (1).)

1. A method for operating a drive train (2) for a motor vehicle (1), wherein the drive train (2) has at least one internal combustion engine (4), an electric machine (5) which is or can be coupled to the internal combustion engine (4) in terms of drive, and a starting clutch (7), by means of which the internal combustion engine (4) and the electric machine (5) are coupled in terms of drive to an output shaft (6) of the drive train (2), characterized in that, in a starting mode of operation of the drive train (2), the internal combustion engine (4) is operated without ignition with the starting clutch (7) disengaged and is drawn by means of the electric machine (5) to a starting rotational speed which is higher than the idling rotational speed of the internal combustion engine (4), after the starting speed is reached, the internal combustion engine (4) is operated in an ignition mode and the starting clutch (7) is engaged.

2. Method according to claim 1, characterized in that the ignition mode of the internal combustion engine (4) is started directly after the cranking rotational speed is reached.

3. A method according to any one of the foregoing claims, characterised in that, as the combustion engine (4) starts to operate in an ignited manner, a torque is generated by means of the electric machine (5) which is comparable in magnitude and opposite in direction to the torque supplied by the combustion engine (4).

4. Method according to any one of the preceding claims, characterized in that the torque is provided by means of the electric machine (5) by operating the electric machine (5) in generator mode, the electric energy provided by the electric machine (5) while the generator is operating being temporarily stored or converted into heat.

5. A method according to any one of the foregoing claims, characterised in that the starting clutch (7) is engaged after the internal combustion engine (4) has started to operate in an ignited manner.

6. A method according to any one of the foregoing claims, characterised in that the electric machine (5) is deactivated when the starting clutch (7) is engaged, or that an auxiliary torque is applied to the torque of the combustion engine (4) by means of the electric machine (5) from the start of the engagement of the starting clutch (7).

7. A method according to any one of the foregoing claims, characterised in that the starting rotational speed is selected to be the same as the rotational speed at which the engine (4) provides maximum torque.

8. Method according to any of the preceding claims, characterized in that the starting rotational speed is chosen to be equal to the rotational speed at which the maximum torque of the internal combustion engine (4) corresponds to the maximum torque that can be provided by means of the electric machine.

9. Method according to one of the preceding claims, characterized in that a separating clutch (10) is present between the internal combustion engine (4) and the electric machine (5) in terms of drive technology, which separating clutch is engaged in order to tow the internal combustion engine (4) by means of the electric machine (5).

10. A drive train (2) for a motor vehicle (1), in particular for carrying out a method according to one or more of the preceding claims, wherein the drive train (2) has at least one internal combustion engine (4), an electric machine (5) which is coupled or can be coupled to the internal combustion engine (4) in terms of drive and a starting clutch (7), wherein the internal combustion engine (4) and the electric machine (5) are coupled to an output shaft (6) of the drive train (2) in terms of drive by means of the starting clutch, characterized in that the drive train (2) is designed such that, in a starting mode of operation of the drive train (2), the internal combustion engine (4) is operated without ignition with the starting clutch (7) disengaged, the internal combustion engine is drawn to a starting rotational speed by means of the electric machine (5), which is greater than an idle rotational speed of the internal combustion engine (4), after the starting speed is reached, the internal combustion engine (4) is operated in an ignition mode and the starting clutch (7) is engaged.

Technical Field

The invention relates to a method for operating a drive train for a motor vehicle, wherein the drive train has at least one internal combustion engine, an electric machine that is or can be coupled to the internal combustion engine in terms of drive, and a starting clutch, by means of which the internal combustion engine and the electric machine are coupled in terms of drive to an output shaft of the drive train. The invention further relates to a drive train for a motor vehicle.

Background

DE 102017203623 a1 is known from the prior art, for example. This patent document describes a method for carrying out a starting process of a motor vehicle having a hybrid drive system which comprises an output shaft, a starting element, an internal combustion engine having an output shaft and an electric machine which can be connected to the output shaft of the internal combustion engine, wherein during the starting process for preloading the internal combustion engine the electric machine is operated as a generator.

Disclosure of Invention

The object of the present invention is to provide a method for operating a drive train for a motor vehicle, which has the advantage over known methods of providing a high drive torque on an output shaft very quickly, in particular in a particularly efficient manner.

According to the invention, this is achieved by a method for operating a drivetrain for a motor vehicle having the features of claim 1. In this case, it is provided that, in a starting mode of operation of the drive train, the internal combustion engine is operated without ignition with the starting clutch disengaged and is dragged by the electric machine to a starting rotational speed which is higher than the idle rotational speed of the internal combustion engine, wherein, after reaching the starting rotational speed, the internal combustion engine is operated with ignition and the starting clutch is engaged.

The method is used for operating a power transmission device which is or can be at least a component of a motor vehicle. The drive train is used to drive the motor vehicle, i.e., for this purpose, provides a drive torque for driving the motor vehicle. In order to generate the drive torque, the drive train has an internal combustion engine and an electric machine, which at least at times jointly provide the drive torque. However, it is also possible in some cases to provide that only the internal combustion engine is used and the electric machine is not used, and/or that the electric machine is used and the internal combustion engine is not used to provide the drive torque.

The electric machine can be coupled to the internal combustion engine in terms of drive technology or at least can be coupled thereto. In the first case, the electric machine is in particular rigidly and/or permanently connected to the internal combustion engine. For example, the electric machine is then directly coupled to the output shaft of the internal combustion engine and is preferably arranged coaxially with respect to this output shaft. However, it is also possible to provide that the electric machine is coupled to the output shaft in terms of drive via an intermediate transmission, wherein the intermediate transmission has a transmission ratio other than 1.

In the case of a coupling of the electric machine to the internal combustion engine, the internal combustion engine and the electric machine are jointly coupled to a starting clutch and can be coupled to the output shaft by means of the starting clutch. In this connection, in a first switching position of the starting clutch, the internal combustion engine and the electric machine are jointly decoupled from the output shaft, whereas in a second switching position of the starting clutch, the internal combustion engine and the electric machine are jointly coupled to the output shaft.

However, it can also be provided that the electric machine is only couplable to the internal combustion engine. For this purpose, the electric machine is coupled to the internal combustion engine, specifically to its output shaft, for example, by a separating clutch. In particular, the electric machine is preferably coupled in terms of drive technology, in particular rigidly and/or permanently, to the intermediate shaft, but particularly preferably via an intermediate transmission. The intermediate shaft is coupled, for example, via a separating clutch to the internal combustion engine on the one hand and via a starting clutch to an output shaft of the drive train on the other hand.

Similarly to the above embodiments, when in the first shift position of the starting clutch, the output shaft is decoupled from the intermediate shaft, while when the second shift position occurs, the output shaft is coupled with the intermediate shaft. In this connection, at least the electric machine is coupled to the output shaft in terms of drive when the starting clutch is engaged, i.e. when the second shift position occurs. If the separating clutch, which is additionally between the internal combustion engine and the electric machine, is at least partially or completely engaged, the internal combustion engine is also drivingly coupled to the output shaft of the drive train.

The starting clutch is located in terms of drive technology between the internal combustion engine and the electric machine on the one hand and the output shaft of the drive train on the other hand. The output shaft is preferably coupled to at least one wheel of the motor vehicle, particularly preferably to a plurality of wheels of the motor vehicle, in terms of drive technology, for example by means of a transmission or a manual transmission. The transmission is used to set a gear ratio selected from a plurality of gear ratios between the output shaft and at least one wheel of the motor vehicle. This means that the transmission has a plurality of gear ratios, one of which is selected and set on the transmission, so that the set gear ratio then occurs between the output shaft and at least one wheel.

The drive train can now be operated, for example, in an idle operating mode. In the idle operating mode, the starting clutch is disengaged or completely disengaged, i.e. is in its first switching position. Accordingly, both the internal combustion engine and the electric machine are completely decoupled from the output shaft. In the idle operating mode, the internal combustion engine is operated at idle speed in an ignited manner. This means that the internal combustion engine is supplied with fuel and is adjusted in such a way that it generates a torque corresponding to the drag torque of the internal combustion engine at the respective current rotational speed of the internal combustion engine. In this connection, the rotational speed of the internal combustion engine remains constant or at least almost constant.

The rotational speed of the internal combustion engine is set to an idle rotational speed, in particular to an idle rotational speed. The idle speed is understood to be the engine speed which is greater than the minimum speed of the internal combustion engine and is selected such that stable operation of the internal combustion engine occurs and at the same time low noise generation and low fuel consumption occur. Conversely, the lowest rotational speed is the rotational speed at which the internal combustion engine can be operated without an externally supplied torque, i.e., from which the internal combustion engine can continue to increase its rotational speed autonomously and without an external torque intervention. In general, when the motor vehicle is at a standstill, i.e. when the speed is zero, an idle speed is set at the drive train and is used to operate the drive train.

Conversely, if the motor vehicle is to be accelerated as quickly as possible, the start-up operating mode is set at the drive train. The start operating mode enables a so-called start control of the motor vehicle, which in particular leads to a maximum and/or in particular effective acceleration of the motor vehicle. In the starting mode of operation, the starting clutch is disengaged, i.e. completely disengaged, so that the internal combustion engine and the electric machine are completely decoupled from the output shaft. If the starting clutch is still engaged or at least partially engaged at the beginning of the start-up mode of operation, the starting clutch is fully disengaged.

If the starting clutch is completely disengaged, the internal combustion engine is drawn to a starting speed by means of the electric machine, wherein the internal combustion engine is simultaneously operated in a non-ignited manner. Operating in a non-ignited mode is understood to mean operating the internal combustion engine without fuel delivery. In this regard, for operation in a non-ignition mode, fuel delivery to the internal combustion engine is interrupted. During operation in the non-ignited mode, there is no combustion of fuel in the internal combustion engine.

The internal combustion engine is thus drawn to the starting speed only by means of the electric machine, for which purpose electrical energy, for example, from an energy store of the motor vehicle, specifically the drive train, is supplied to the internal combustion engine. The cranking rotation speed is greater than an idle rotation speed of the internal combustion engine, for example, the cranking rotation speed is at least 2 times the idle rotation speed. Particularly preferably, the cranking rotational speed is at least 5 times, at least 7.5 times or at least 10 times the idling rotational speed.

If the internal combustion engine reaches a starting speed, i.e. its current speed corresponds to the starting speed, the internal combustion engine is operated in an ignition mode and the starting clutch is engaged. Therefore, the internal combustion engine is switched from non-ignited to ignited operation only after the starting speed has been reached. Only after this switchover is the starting torque provided at least in part by the internal combustion engine. For this purpose, a starting clutch is additionally engaged. This is extremely energy-saving and, in addition, comfortable for the occupants of the motor vehicle, since the operation of the internal combustion engine in a non-ignited manner and its acceleration by means of the electric machine is accompanied by very low noise generation and, compared to the ignition acceleration of the internal combustion engine to the starting speed, is considerably less noisy and vibrates less.

In general, the start-up operating mode is started from the idle operating mode, i.e. the drive train is switched directly from the idle operating mode into the start-up operating mode. In the idle operating mode, the internal combustion engine is operated in an ignited manner, whereas in the start operating mode, a non-ignited operation of the internal combustion engine is provided first. Accordingly, when switching from the idle operating mode to the start operating mode, the internal combustion engine switches from operating in an ignited mode to operating in a non-ignited mode and simultaneously starts to be dragged to the starting speed by means of the electric machine. In this case, the electric machine is operated such that, despite the internal combustion engine being switched from being operated in an ignited mode to being operated in a non-ignited mode, no reduction in rotational speed occurs, but rather the rotational speed is increased continuously by means of the electric machine from the idling rotational speed up to the starting rotational speed. Thereby, the advantages already described above are achieved.

For example, it is provided that a starting operating mode of the drive train is initiated as soon as a service brake of the motor vehicle is activated and an accelerator pedal of the motor vehicle is actuated. The internal combustion engine is therefore operated without ignition with the service brake activated and is pulled to the starting speed by means of the electric machine, so that the motor vehicle remains stationary. After the starting rotational speed has been reached, the starting clutch is also initially disengaged, so that the vehicle remains stationary. It can be provided that the internal combustion engine is also operated in a non-ignited manner and is maintained at the starting speed by means of the electric machine.

However, it can also be provided that the internal combustion engine is switched from a non-ignited operation to an ignited operation after reaching the starting speed. In particular, it is preferred that the starting clutch is engaged only when the service brake of the motor vehicle is released, i.e. for example, when the brake pedal of the motor vehicle is no longer actuated. Preferably, the starting clutch is disengaged just when the service brake is released, so that the torque provided by the internal combustion engine is present as drive torque at the output shaft and accelerates the motor vehicle.

In a further development of the invention, it is provided that the ignition mode operation of the internal combustion engine is started directly after the cranking rotational speed is reached. Reference is made to the above. In particular, it is preferred that, after the starting speed has been reached and the ignition mode of the internal combustion engine has been started, the starting clutch is initially engaged, in particular until the service brakes of the motor vehicle are released or completely released. The direct start of the ignition mode operation after the starting speed is reached ensures that a high drive torque is directly available with the internal combustion engine when the starting clutch is engaged.

In a further development of the invention, it is provided that, with the start of the internal combustion engine operating in the spark mode, a torque is generated by means of the electric machine which corresponds in magnitude to the torque provided by the internal combustion engine and is opposite thereto. By starting the operation in the spark mode, the internal combustion engine is preferably set such that it outputs a torque. In other words, the torque generated by the internal combustion engine is greater than the friction torque of the internal combustion engine at the currently existing rotational speed, in particular at the starting rotational speed.

In order to nevertheless maintain the internal combustion engine at the starting speed, the electric machine is operated in such a way that a torque is generated which is opposite to the torque of the internal combustion engine. In other words, the electric machine is adjusted in such a way that the rotational speed of the internal combustion engine is maintained at the starting rotational speed. For example, the internal combustion engine and the electric machine have the same power rating for this purpose. The internal combustion engine is preferably adjusted in such a way that it provides the maximum torque that can be achieved at the current rotational speed, in particular at the starting rotational speed. If the torque that can be provided by means of the electric machine is less than this torque, it is particularly preferred to adjust the torque of the internal combustion engine to the maximum torque that can be provided by means of the electric machine.

In other words, the internal combustion engine is already ready to provide a large driving torque, which is first suppressed by means of the electric machine. The electric machine is therefore used to preload the combustion engine. This results in an extremely rapid supply of the drive torque, so that a high acceleration of the motor vehicle is achieved.

In a further development of the invention, provision is made for the electric machine to be operated as a generator, for torque to be provided by means of the electric machine, and for the electric energy provided by the electric machine to be temporarily stored or converted into heat during the operation of the generator. As already explained above, the electric machine can be electrically coupled to an accumulator for temporarily storing electric energy. In this connection, the electric machine can be operated on the one hand by means of the electrical energy drawn from the energy store. Conversely, the electrical energy provided by means of the electric machine can be fed to the energy store.

After starting the spark-ignition operation of the internal combustion engine in the start-up operating mode, the electric machine absorbs the torque generated by the internal combustion engine. In this case, the mechanical energy of the internal combustion engine is converted into electrical energy. The electrical energy is stored, for example, temporarily in an accumulator. In particular, it is advantageously provided that the electric machine is operated with electrical energy drawn from the energy store in order to bring the internal combustion engine to a starting speed. This means that the state of charge of the energy store drops. During the generator operation of the electric machine in order to maintain the internal combustion engine at the starting speed, the energy storage device is supplied again with electrical energy, so that the previously drawn electrical energy is at least partially or even completely compensated.

However, it can also be provided that the electrical energy provided by the electric machine is converted directly into heat, for example by short-circuiting the electric machine. This can be done in particular if the energy store is completely full, i.e. no longer able to absorb electrical energy. For example, during the operation of the internal combustion engine in the ignition mode, the electrical energy provided by the electric machine is introduced into the energy storage until the energy storage is completely filled. Subsequently, the electrical energy is converted into heat, in particular until the starting clutch is engaged. This type of procedure always allows preloading the internal combustion engine by means of the electric machine.

In a further development of the invention, the starting clutch is engaged after starting the ignition mode of the internal combustion engine. Therefore, the starting clutch is not engaged until after the start of the operation in the ignition mode, so that a time interval exists. This ensures that the internal combustion engine provides a sufficiently large torque when the starting clutch is engaged. It is particularly preferred that the starting clutch is engaged only when the internal combustion engine provides a predetermined setpoint torque, which is overcome by means of the electric machine. For example, the set torque may correspond to the maximum torque achievable at the cranking speed. The described procedure again ensures rapid acceleration of the motor vehicle.

In a further development of the invention, the electric machine is deactivated when the starting clutch is engaged, or an auxiliary torque is applied to the torque of the internal combustion engine by means of the electric machine from the start of the engagement of the starting clutch. In particular, the electric machine is deactivated if a torque opposite to the torque of the internal combustion engine has previously been generated by means of the electric machine. Due to the switching off of the electric machine, the drive torque of the drive train present at the output shaft is provided in this case exclusively by means of the internal combustion engine.

Alternatively, provision may be made for the torque generated by the internal combustion engine to be assisted by means of the electric machine, so that the drive torque occurring at the output shaft is composed of the torque generated by the internal combustion engine and the torque generated by the electric machine. In particular, it is preferred that, with the aid of the internal combustion engine, the maximum torque that can be achieved at the starting speed is generated, and, conversely, the electric machine is operated such that the drive torque that occurs at the output shaft corresponds to the target drive torque. The target drive torque is preset, for example, by a driver of the motor vehicle or a driver assistance device of the motor vehicle. It is also possible, of course, to provide that the electric motor is actuated to generate its maximum torque, so that the maximum achievable drive torque is present at the output shaft. In this way, a particularly high power output can be achieved.

A further development of the invention provides that the starting rotational speed is selected to be the same as the rotational speed at which the engine provides the maximum torque. The maximum torque corresponds to the maximum torque of the internal combustion engine at all possible rotational speeds of the internal combustion engine. The same as the maximum torque is not to be understood as the maximum torque at a specific rotational speed. It is, however, clear that the maximum torque coincides with the maximum torque for the rotational speeds at which the maximum torque on the internal combustion engine is available, i.e. corresponds to each other. By means of the described procedure, it is ensured that a particularly high drive torque is achieved on the output shaft.

In a further development of the invention, the starting rotational speed is selected to be equal to a rotational speed at which the maximum torque of the internal combustion engine corresponds to the maximum torque that can be provided by means of the electric machine. In this case, the maximum torque corresponds to the maximum torque that can be achieved by means of the internal combustion engine at the starting speed. The maximum torque may (but need not necessarily) correspond to the maximum torque. The maximum torque should now correspond to the maximum torque that can be provided by means of the electric machine, so that the torque generated by the internal combustion engine can be balanced by means of the electric machine, so that the described preloading of the internal combustion engine is achieved.

From this maximum torque (which corresponds to the maximum torque that can be provided by means of the electric machine), a rotational speed is determined at which a maximum torque exists that represents the maximum torque achievable of the internal combustion engine. Subsequently, the starting rotational speed is equalized to this rotational speed. This ensures that a high drive torque is achieved despite the limitations of the electric machine.

In a further development of the invention, a separating clutch is provided in the drive between the internal combustion engine and the electric machine, which separating clutch is engaged in order to drag the internal combustion engine by means of the electric machine. The disconnect clutch has been indicated above. In a first switching position, the separating clutch is disengaged, so that the internal combustion engine is separated from the electric machine in terms of drive. In the second switching position, the clutch is disengaged, so that the internal combustion engine is preferably coupled rigidly to the electric machine. To achieve a towing of the internal combustion engine by means of the electric machine, the separating clutch is engaged. This is the case, in particular, if the drive train has previously been operated in the idle operating mode (in which the separator clutch is disengaged). The separating clutch achieves a particularly high energy efficiency of the power transmission device.

The invention further relates to a drive train for a motor vehicle, in particular for carrying out a method according to an embodiment within the scope of the invention, wherein the drive train has at least one internal combustion engine, an electric machine which is or can be coupled to the internal combustion engine in terms of drive and a starting clutch, the internal combustion engine and the electric machine being coupled to an output shaft of the drive train in terms of drive via the starting clutch. In this case, it is provided that the drive train is designed in such a way that, in a starting mode of operation of the drive train, the internal combustion engine is operated without ignition with the starting clutch disengaged and is dragged by means of the electric machine to a starting rotational speed, which is greater than the idling rotational speed of the internal combustion engine, wherein, after reaching the starting rotational speed, the internal combustion engine is operated with ignition and the starting clutch is engaged.

The advantages of these designs of the power transmission device and of the method of this type have already been pointed out. Not only the power transmission device but also the method for its operation can be modified according to the embodiments within the scope of this specification, so that reference is made to these embodiments.

The invention also relates to a motor vehicle having such a drive train.

Drawings

The invention is explained in detail below on the basis of the embodiments shown in the figures, without restricting the invention. The single figure shows a schematic representation of a drive train for a motor vehicle.

Detailed Description

The figure shows a schematic representation of a motor vehicle 1 with a drive train 2 and at least one wheel 3 which can be driven by means of the drive train 2. The drive train 1 has an internal combustion engine 4 and an electric machine 5, which is at least partially drivingly coupled to an output shaft 6 of the drive train 2. In the exemplary embodiment shown here, the output shaft 6 is drivingly coupled to an intermediate shaft 8 via a starting clutch 7, which is rigidly and permanently coupled to the electric machine 5.

For example, the electric machine 5 is coupled to the intermediate shaft 8 via an intermediate gear 9. Conversely, the internal combustion engine 4 is coupled in terms of drive to the intermediate shaft 8 via a separating clutch 10. In this connection, the intermediate shaft 8 is completely decoupled from the internal combustion engine 4 when the separating clutch 10 is disengaged, and is rigidly connected to the internal combustion engine when the separating clutch 10 is engaged. Similarly, with the starting clutch 7 disengaged, the output shaft 6 is completely decoupled from the intermediate shaft 8 and is rigidly coupled to the intermediate shaft when the starting clutch 7 is engaged. The electric machine 5 is electrically coupled to an accumulator 11 for temporarily storing electric energy.

In the illustrated exemplary embodiment, the output shaft 6 is drivingly coupled to at least one wheel 3 of the motor vehicle 1 via a transmission 12. It is obvious that the transmission 12 can also be located elsewhere in the power transmission device 2 or be omitted altogether. It is also possible to design the starting clutch 7 so as to be integrated into the transmission 12, so that the output shaft 6 is also located in the transmission 12, for example as an intermediate shaft or the like.

In the starting mode of operation of the drive train 2, it is now provided that the starting clutch 7 is completely disengaged as long as it is not completely disengaged. Subsequently, the internal combustion engine 4 is drawn by means of the electric machine 5 to a starting rotational speed which is greater than the idle rotational speed of the internal combustion engine 4. The internal combustion engine 4 is operated in a non-ignited manner. This means that no fuel is combusted in the internal combustion engine, in particular no fuel is supplied to the internal combustion engine. Preferably, electrical energy is taken from the energy storage 11 for towing the internal combustion engine 4 by means of the electric machine 5.

After the start-up speed has been reached, the internal combustion engine 4 is switched from being operated in the non-ignited mode to being operated in the ignited mode. Preferably, the internal combustion engine 5 is adjusted such that it outputs a torque greater than 0 Nm. At the same time, the electric machine 5 is adjusted in such a way that the torque generated by the electric machine reacts to the torque of the internal combustion engine 4 and corresponds in magnitude to the torque of the internal combustion engine. Accordingly, the rotational speed of the internal combustion engine 4 is kept constant, i.e. at the starting rotational speed, despite the torque generated by means of the electric machine 5.

Subsequently, to accelerate the motor vehicle 1, the starting clutch 7 is engaged and either the electric machine 5 is deactivated or the electric machine is adjusted for assisting the torque generated by the internal combustion engine 4. In the latter case, a drive torque jointly provided by the internal combustion engine 4 and the electric machine 5 is present on the output shaft 6. Due to the preloading of the combustion engine 4 carried out beforehand, a very high drive torque can be provided very quickly at the output shaft.

List of reference numerals

1 Motor vehicle

2 power transmission device

3 wheel

4 internal combustion engine

5 electric machine

6 output shaft

7 starting clutch

8 middle shaft

9 intermediate transmission mechanism

10 disconnect clutch

11 energy accumulator

12 speed variator