Method for operating a drive system of a motor vehicle and drive system

Abstract

A method and a drive system for operating a motor vehicle. The drive system has a first planetary gear (2) having a sun gear, a ring gear (5) and a planet carrier (6), wherein the sun gear (4) can be fixedly braked on the housing side via a first switching element and can be coupled to the planet carrier via a second switching element (B) while providing an integral rotation on the first planetary gear. The drive system has a first electric motor, which is coupled to the ring gear, and a second electric motor, which can be coupled to the sun gear. In order to implement a load switch from a first gear for the first electric motor to a second gear for the first electric motor during pure electric driving, the second electric motor is coupled to the sun gear via a third switching element. Subsequently, the switching element to be engaged for the load switch is unloaded via the second electric motor and then engaged. Subsequently, the switching element to be engaged for the load switch is synchronized and then engaged.

Description

Technical Field

[0001] The invention relates to a method for operating a drive system of a motor vehicle. The invention also relates to a drive system. Background Art

[0002] DE 10 2013 214 317 A1 discloses a drive system for a motor vehicle, which has at least one planetary gear and two motors. One motor is permanently coupled to the sun gear of the planetary gear. Another motor is coupled to the sun gear of the planetary gear together with another motor or to the ring gear of the planetary gear, depending on the switching position of two form-locking switching elements. The ring gear of the planetary gear is either fixedly braked on the housing side or coupled to the planet carrier of the planetary gear, depending on the switching position of two other form-locking switching elements. These two other form-locking switching elements can also be disconnected like the two form-locking switching elements that cooperate with the other motor. In addition to the first planetary gear, the drive system of DE 10 2013 214 317 A1 can also have at least one other planetary gear. In addition, DE 10 2013 214 317 A1 also discloses a method for operating such a drive system. In particular, a method for carrying out an electromotive active synchronized load switching is disclosed.

[0003] There is a need for novel drive systems and methods for operating such drive systems which allow load shifting between electric gears for a first electric machine without friction-locking load shifting elements and purely electric starting with high comfort and efficiency. Summary of the invention

[0004] Based on this, the object of the present invention is to provide a novel method for operating a drive system of a motor vehicle and a corresponding drive system.

[0005] This object is achieved according to a first aspect by a method according to the invention. In order to realize a load switch from a first gear for a first electric machine to a second gear for the first electric machine during pure electric driving, at least the following steps are performed: First, the second electric machine is coupled to the sun gear of the first planetary gear via a third form-locking switching element, for which the third form-locking switching element is closed. Then, the form-locking switching element to be hung out for the load switch is unloaded via the second electric machine. Subsequently, the form-locking switching element to be hung out for the load switch is hung out. Subsequently, the form-locking switching element to be hung in for the load switch is synchronized. Subsequently, the form-locking switching element to be hung in for the load switch is hung in.

[0006] With these method steps, in the drive system defined in the invention, load switching is achieved during purely electric driving for the gears of the first electric machine, without the need for friction-locking shift elements, using only form-locking shift elements.

[0007] According to a second aspect, this object is achieved by a method according to the invention. For purely electric starting, at least the following steps are first performed: First, the second electric machine is coupled to the sun gear of the first planetary gear via a third form-locking shift element, for which the third form-locking shift element is closed. Then, when or after a request for a starting torque is made, a torque is applied to the ring gear of the first planetary gear via the first electric machine, and the second electric machine is operated in a speed control mode in such a way that the second electric machine supports the torque on the sun gear of the second planetary gear.

[0008] With these method steps, a purely electric start can be achieved in the drive system defined in the present invention without the need for friction-locking shift elements.

[0009] If the drive system has an internal combustion engine in addition to the first and second electric machines, the internal combustion engine is decoupled or remains decoupled for carrying out the method according to the first aspect and for carrying out the method according to the second aspect.

[0010] If the drive system has a second planetary gear in addition to the first planetary gear, the second electric machine is either fixedly connected to the rotatable element of the second planetary gear or can be coupled to the rotatable element of the second planetary gear via at least one further form-locking shift element.

[0011] A drive system is defined in the present invention. The drive system is compact, provides multiple gears and allows the drive system to operate in multiple operating modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The preferred improved scheme is obtained from the following description. The embodiments of the present invention are described in more detail with reference to the accompanying drawings, but are not limited thereto. Among them:

[0013] Figure 1 A schematic diagram showing a first drive system of a motor vehicle;

[0014] Figure 2 A schematic diagram showing a second drive system of a motor vehicle;

[0015] Figure 3 Shows Figure 1 , 2 Switching diagram of the drive system;

[0016] Figure 4 A schematic diagram showing a third drive system of a motor vehicle;

[0017] Figure 5 A schematic diagram showing a fourth drive system of a motor vehicle;

[0018] Figure 6 Show Figure 4 , 5 , 7, 8, the switching diagram of the drive system;

[0019] Figure 7 A schematic diagram showing a fifth drive system of a motor vehicle;

[0020] Figure 8 A schematic diagram showing a sixth drive system of a motor vehicle;

[0021] Fig. 9 A schematic diagram showing a seventh drive system of a motor vehicle;

[0022] Fig.10 A schematic diagram showing an eighth drive system of a motor vehicle;

[0023] Fig.11 Show Fig. 9 , 10 Switching diagram of the drive system;

[0024] Fig.12 A schematic diagram showing a ninth drive system of a motor vehicle;

[0025] Fig.13 A schematic diagram showing a tenth drive system of a motor vehicle;

[0026] Fig.14 Show Fig.12 , 13 Switching diagram of the drive system. DETAILED DESCRIPTION

[0027] Figure 1A drive system 1 is shown which comprises two planetary gears 2 and 3 and two electric machines 13 and 14 . Figure 2 , 4 , 5 , 7 , 8 , 9 , 10 , 12 and 13 also respectively show a drive system 1 which has two planetary gears 2 and 3 and two electric machines 13 and 14 .

[0028] Although a drive system having two planetary gear transmissions 2 and 3 is particularly preferred, it should be pointed out that only the planetary gear transmission 2, which is referred to below as the first planetary gear transmission 2, is a mandatory structural component of the drive system, while the planetary gear transmission 3, which is referred to below as the second planetary gear transmission 3, is a preferably present but optional structural component of the drive system.

[0029] The first planetary gear 2 has a sun gear 4 , a ring gear 5 and a planet carrier 6 .

[0030] The sun gear 4 of the first planetary gear 2 can be fixedly braked on the housing side via a first positive-locking shift element A. Figure 1 , 2 This is the case in all of the drive systems shown in , 4, 5, 7, 8, 9, 10, 12 and 13.

[0031] Furthermore, the sun gear 4 of the first planetary gear 2 can be coupled to the planet carrier 6 of the first planetary gear 2 via a second positive-locking shift element B while providing a block rotation on the first planetary gear 2, wherein the planet carrier 6 of the first planetary gear 2 is fixedly connected to the output shaft 9. Figure 1 , 2 This is true for all drive systems 1, 2, 3, 4, 5, 7, 8, 9, 10, 12, and 13.

[0032] As already described, the drive system 1 has two electric machines 13 and 14, wherein the electric machine 13 is hereinafter referred to as the first electric machine 13 and the electric machine 14 is hereinafter referred to as the second electric machine 14. Figure 1 , 2 This is true for all drive systems of , 4, 5, 7, 8, 9, 10, 12 and 13.

[0033] The first electric machine 13 is coupled to the ring gear 5 of the first planetary gear 2 either directly or indirectly via the optional second planetary gear 3 .

[0034] exist Figure 1 , 2, 12 and 13, the first motor 13 is indirectly coupled to the ring gear 5 of the first planetary gear 2 via the second planetary gear 3, more precisely, Figure 1 and Figure 2 In the following manner, the first motor 13 acts on the planet carrier 12 of the second planetary gear transmission 3, so that the first motor is coupled to the ring gear 5 of the first planetary gear transmission 2. Fig.12 , 13 In the embodiment of the present invention, the first electric machine 13 is coupled to the ring gear 11 of the second planetary gear 13 , and the ring gear 5 of the first planetary gear 2 is coupled to the planet carrier 12 of the second planetary gear 3 .

[0035] In addition to the first electric machine 13 , the drive system also comprises a second electric machine 14 . The second electric machine 14 can be coupled to the sun gear 4 of the first planetary gear 2 via a third form-locking shift element C either directly or indirectly via the second planetary gear 3 .

[0036] Therefore, in Figure 1 , 2 , 4, 5, 7, 8, 12 and 13, the second electric machine 14 is respectively coupled directly to the sun gear 4 of the first planetary gear 2 when the third form-locking shift element C is closed.

[0037] And in Fig. 9 and Fig.10 In the case where the third form-locking shift element C is closed, the second electric machine 14 is coupled to the sun gear 4 of the first planetary gear 2 via the second planetary gear 3, that is, in the following manner: Fig. 9 and Fig.10 In , the second electric machine 14 is coupled to the planet carrier 12 of the second planetary gear 3 , wherein when the third form-locking shift element C is closed, the ring gear 11 of the second planetary gear 3 is coupled to the sun gear 4 of the first planetary gear 2 .

[0038] also, Figure 1 , 2 All drive systems of 1, 4, 5, 7 to 10 and 12, 13 have in common that there are two drive shafts 7, 8 and an output shaft 9. A first motor 13 is coupled to the first drive shaft 7. A second motor 14 is coupled to the second drive shaft 8. The output shaft 9 is coupled to a not shown output.

[0039] The planet carrier 6 of the first planetary gear 2 is always fixedly coupled to the output shaft 9. The ring gear 5 of the first planetary gear 2 is always coupled to the first drive shaft 7 and thus to the first electric machine 13, more precisely, as already mentioned, in Figure 1 ,2 , 12 and 13 are indirectly coupled via the second planetary gear 3, and Figure 4 , 5 , 7, 8, 9 and 10 are directly coupled.

[0040] If the drive system 1 has an optional, but preferred second planetary gear 3, the second electric machine 14 is either fixedly coupled to a rotatable element of the second planetary gear 3 or alternatively can be coupled to a rotatable element of the second planetary gear 3 as a function of the shift position of at least one further form-locking shift element E and F. Figure 1 and 2 In FIG. 1 , the second electric machine 14 is fixedly coupled to the sun gear 10 of the second planetary gear 3 . Figure 4 and 5 In FIG. 1 , the second electric machine 14 is fixedly coupled to the planet carrier 12 of the second planetary gear 3. Figure 7 and 8 9 and 10, the second electric machine 14 is also fixedly coupled to the planet carrier 12 of the second planetary gear 3. Fig.12 and 13 In the embodiment, the second electric machine 14 is coupled either to the planet carrier 12 of the second planetary gear 3 or to the ring gear 11 of the second planetary gear 3, depending on the shift position of the shift elements F and E, which are form-locking shift elements. Fig.12 and 13 In the embodiment, when the form-locking switching element F is closed, the second electric machine 14 is coupled to the planet carrier 12 of the second planetary gear 3. When the form-locking switching element E is closed, Fig.12 , 13 In FIG. 1 , the second electric machine 14 is coupled to the ring gear 11 of the second planetary gear 3 .

[0041] exist Figure 1 and 2 In the drive train of , when the form-locking shift element E is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the sun gear 10 of the second planetary gear 3. When the form-locking shift element F is closed, the ring gear 5 of the second planetary gear 2 is coupled to the sun gear 10 of the second planetary gear 3.

[0042] exist Figure 1 and 2 In the embodiment of the present invention, via two positive-locking shift elements G and D, the ring gear 11 of the second planetary gear 3 can be coupled to the output shaft 9 either when the shift element G is closed or can be braked fixedly relative to the housing when the shift element D is closed.

[0043] Figure 1 The drive system is a pure electric drive system, and Figure 2 The drive system is a hybrid drive system which, in addition to the two electric machines 13 and 14 , comprises an internal combustion engine 15 which can be coupled to the second drive shaft 8 of the drive system when the clutch K0 is closed.

[0044] Figure 3 Shown for Figure 1 and Figure 2 The switching matrix of the drive system, more precisely, the switching matrix without considering the clutch K0 and the internal combustion engine 15. The shift elements that are closed in the respective gears are Figure 3 The switching matrices are marked by X.

[0045] Gear positions 1 to ZG2 are gear positions for the second motor 14, and when Figure 2 When the clutch K0 is closed in the drive system of , it is a gear for the internal combustion engine 15. Gears 4.1 to 4.11 are variants of the fourth gear.

[0046] Gear positions ZG1 and ZG2 are additional gear positions.

[0047] The gear positions E1 and E2 are gear positions for the first electric machine 13. The switching states EDA-A and EDA-R involve activation of electric power in the forward direction or the reverse direction.

[0048] It should be pointed out here that Figure 1 and 2 The second electric machine 14, which is directly coupled to the sun gear 10 of the second planetary gear 3, can also be connected to the sun gear 10 of the second planetary gear 3 with another planetary gear set or spur gear stage connected in between. Correspondingly, the first electric machine 13 can also be connected to the planet carrier 12 of the second planetary gear 3 via another transmission ratio stage. As already described, gears 1 to ZG2 are gears for the second electric machine 14 and / or the internal combustion engine 15. Gears E1 and E2 are gears for the first electric machine 13.

[0049] In the first purely electric gear for the electric machine 13, according to Figure 3 , the first form-locking switching element A is closed. Figure 1 and 2 In the embodiment, the sun gear 4 of the first planetary gear 2 is fixedly braked on the housing side. The planet carrier 6 of the second planetary gear 2 is coupled to the output shaft 9 , and the electric motor 13 is connected to the sun gear 5 of the first planetary gear 2 .

[0050] When the second purely electric gear E2 for the first electric machine 3 is active, the second form-locking shift element B is closed, wherein the sun gear 4 of the first planetary gear 2 is then connected to the planet carrier 6 of the first planetary gear 2 while providing for the overall rotation of the first planetary gear 2 and then connected together with the planet carrier 6 to the output shaft 9. When the planetary gear is locked, there is a speed equality between the sun gear 4, the ring gear 5 and 6 of the planetary gear 2.

[0051] The following is an exemplary example of Figure 1 , 2 The method described in the present invention relates to the implementation of a purely electric load shift (EDS shift) for the purely electric gears E1 and E2 using the first planetary gear 2 and the form-locking shift elements A, B and C. In addition, a method for a purely electric start (EDA start) is presented, which also involves the first planetary gear 2 and the form-locking shift elements A, B and C.

[0052] The first method involves the use of a single-phase electric drive. Figure 2 The drive train of the embodiment of the present invention carries out an electric load shift from a first electric gear for the first electric machine 13 to a second electric gear for the electric machine 13 when the internal combustion engine 15 is decoupled.

[0053] When a pull-type upshift load shift is performed, an EDS load shift is performed from the gear E1 to the gear E2. When a push-type downshift load shift is performed, an EDS load shift is performed from the gear E2 to the gear E1.

[0054] In any case, in order to carry out the EDS load switching, the second electric machine 14 is first coupled to the sun gear 4 of the first planetary gear 2 via the third form-locking shift element C. For this purpose, the third form-locking shift element C is closed.

[0055] The positive locking shifting element to be engaged for the load shift is then unloaded via the second electric machine 14. In the case of a pull-type upshift load shift from the gear E1 to the gear E2, the first positive locking shifting element A is unloaded. In the case of a push-type downshift from the gear E2 to the gear E1, the second positive locking shifting element B is unloaded. The unloaded positive locking shifting element to be engaged is then actually engaged via the second electric machine 14.

[0056] Next, the form-locking shift element to be engaged for the load shift is synchronized. In the case of a pull-type upshift load shift from gear E1 to gear E2, the second form-locking shift element B is synchronized. In the case of a push-type downshift load shift from gear E2 to gear E1, the first form-locking shift element A is synchronized. Subsequently, the form-locking shift element to be engaged for the load shift is engaged.

[0057] Further details are described below for the load switching individually.

[0058] The purely electric EDS load shift from the gear E1 of the first electric machine 13 to the gear E2 with the provision of a traction upshift load shift is initially based on the assumption that the first electric machine 13 is engaged when the form-locking shift element A is closed. Figure 3 The gear E1 of the switching matrix is ​​pure electric driving, and the first motor 13 provides a positive driving torque. Then, the Figure 3 A purely electric load shift from gear E1 to gear E2 of the shift matrix of FIG. 1 , wherein it is assumed below for simplification that the desired drive power and driving speed remain approximately constant during the execution of the shift.

[0059] In order to prepare for the EDS load shift from the gear E1 to the gear E2 , the second electric machine 14 is firstly coupled via the third form-locking shift element C to the sun gear 4 of the first planetary gear 2 .

[0060] The synchronization of the third form-locking shift element C takes place here by means of a speed control of the second electric machine 14 , here by braking to a speed of zero or approximately zero.

[0061] After the second electric machine 14 has been coupled to the sun gear 4 of the first planetary gear 2 by closing the third form-locking shifting element C, the first form-locking shifting element A to be opened for the EDS load shift to be carried out from the gear E1 to the gear E2 is unloaded via the second electric machine 14, namely in such a way that the second electric machine 14 accordingly applies a torque. The third form-locking shifting element C is subjected to a greater load in this case.

[0062] After the first form-locking shifting element A has been unloaded via the second electric machine 14, the first form-locking shifting element A to be engaged is actually engaged or disconnected in that the double shifting element comprising the two shifting elements A and B is transitioned into a neutral position, so that the two form-locking shifting elements A and B are each disconnected.

[0063] Next, the second positive-locking shift element B to be closed for the EDS load shift to be carried out from the gear E1 to the gear E2 is synchronized, namely by correspondingly adjusting the two electric machines 13 and 14. For this purpose, the torque of the first electric machine 13 is reduced and the torque of the second electric machine 14 is increased if necessary, namely, the total power provided by the two electric machines 13 and 14 is kept constant or approximately constant.

[0064] For this purpose, the first planetary gear 2 is brought into a complete revolution, i.e., speed equality is established at the sun gear 4, the planet carrier 6 and the ring gear 5 of the first planetary gear 2, wherein, after the second positive-locking shifting element B to be engaged has been synchronized, the second positive-locking shifting element B is closed and the planetary gear 2 is brought into a complete revolution. The actual load shift from the gear E1 to the gear E2 is then completed.

[0065] Optionally, the torque at the second electric machine 14 can then be reduced in order to load the second form-locking shifting element B, wherein the torque of the first electric machine 13 is then simultaneously increased in order to keep the drive power approximately constant. After the third form-locking shifting element C has been unloaded, the third form-locking shifting element C can be opened without load and the second electric machine 14 can thus be made available for other functions.

[0066] In the case where the first motor 13 Figure 3 The above-described implementation of the traction upshift EDS load switch from gear E1 to gear E2 of the switching matrix provides the advantage that the first electric machine 13 contributes the largest part of the drive power during the switch and therefore the second electric machine 14 can be dimensioned relatively small.

[0067] When the fixed axis transmission ratio i0 of the first planetary gear 2 is selected to “−2”, the first electric machine 13 is ready to control two thirds of the drive power and the second electric machine 14 is ready to control one third of the drive power during the entire revolution just before the positive-locking shift element B is closed.

[0068] The torque on the sun gear 4 of the planetary gear 2 is then only half of the torque on the ring gear 5 of the first planetary gear 2. The second electric machine 14 can be designed with both lower power and lower torque than the first electric machine 13.

[0069] The following describes Figure 3Details of the purely electric EDS push-down load shift from gear E2 to gear E1 of the shift matrix. In the initial situation of the drive system, it is assumed that the first electric machine 13 is driven purely electrically, i.e. when the second form-locking shift element B is closed, more precisely in regenerative braking mode. Starting from this initial situation, a shift from gear E2 to gear E1 should be performed. Figure 3 The gear position is E2 to Figure 3 A purely electric push-down load shift of the gear E1 is described, wherein it is again assumed for simplicity that the desired braking power and the driving speed remain approximately constant during the implementation of the push-down load shift.

[0070] In order to prepare for the push-down load shift to be carried out, the third form-locking shift element C is first closed again in order to couple the second electric machine 14 to the sun gear 4 of the first planetary gear 2 .

[0071] However, it is entirely possible to couple the second electric machine 14 to the sun gear 4 already when the shift element C is closed. If the third positive-locking shift element C is to be closed and synchronized for this purpose, synchronization is again performed by speed control of the second electric machine 14 .

[0072] After coupling the second electric machine 14 to the first planetary gear 2 by closing the third form-locking shift element C, the second electric machine 14 subsequently applies enough torque that the second form-locking shift element B to be opened for the push-down load shift to be performed is unloaded.

[0073] Subsequently, the second form-locking shift element B is unloaded by shifting the double shift element comprising shift elements A and B into a neutral position. While the second form-locking shift element B is unloaded, the third form-locking shift element C takes on the load.

[0074] After the second form-locking shift element B has been disengaged, the first form-locking shift element A to be engaged for the push-down load shift to be carried out is synchronized, more precisely via the control of the two electric machines 13 and 14 .

[0075] For this purpose, when performing a push-down load shift, the sun gear 4 of the first planetary gear 2 is braked to a speed of zero or approximately zero. In this process, the torque of the first electric machine 13 is reduced in value and the torque of the second electric machine 14 is increased in value if necessary. The two electric machines 13 and 14 then act as brakes. During the speed matching phase, the total power provided by the two electric machines 13 and 14 remains constant or approximately constant.

[0076] After the first positive-locking shift element A has been synchronized, it is closed. The actual push-down load shift from the gear E2 to the gear E1 is then complete.

[0077] It is then optionally possible, but recommended, to decouple the second electric machine 14, since it would otherwise remain stationary braked. In order to decouple the second electric machine 14 from the sun gear 4 of the first planetary gear 2, the torque on the second electric machine 14 is reduced, wherein the first positive-locking shift element A is loaded, while the third positive-locking shift element C is unloaded, so that the third positive-locking shift element C can then be unloaded. The second electric machine 14 can then be used for other functions.

[0078] Since the electric machines 13 and 14 can generate both positive and negative torques, the above-described push-down load shift can be implemented particularly advantageously during regeneration.

[0079] Of course, it is also possible to implement a traction-type downshift load switch from gear E2 to gear E1 and from gear E2 to gear E1. Figure 3 The load change of the gear E1 to the gear E2 is a push-type upshift load change. However, the load change of the pull-down shift and the push-type upshift load change are less common than the load change of the pull-up shift and the push-type downshift load change. For the existence of the load change of the pull-down shift, there must be a driving situation in which the motor vehicle is moving slower despite the driving torque, such as when driving up a steep slope. For the load change of the push-down shift, there must be a driving situation in which the motor vehicle is moving faster despite the braking torque, such as when driving down a steep slope.

[0080] The drag downshift load shift and the push upshift load shift are identical in their basic operation in the two above-mentioned shift types, but differ in that the respective torque acts in a different direction.

[0081] The details of pure electric starting are described below, wherein pure electric starting is also referred to as EDA starting. Pure electric EDA starting is described below for the forward driving direction, i.e. for the Figure 3 The operating status of the switching matrix EDA-V.

[0082] In order to prepare for purely electric driving, here in the forward driving direction, the second electric machine 14 is first connected to the sun gear 4 of the first planetary gear 2 via the third form-locking shift element C by closing the third form-locking shift element. The required synchronization of the third form-locking shift element C is carried out via speed control of the third electric machine 14, here by braking the second electric machine 14 to a speed of zero or approximately zero when the vehicle is stationary and the first electric machine 13 is stationary.

[0083] Then, the second motor 14 is brought to the minimum speed in the reverse direction in the speed control mode. Here, good efficiency can be ensured for the second motor 14. Then, when the planet carrier 6 of the first planetary gear 2 stops, the first motor 13 automatically rotates forward without load.

[0084] The speed of the second electric machine 14 is preferably selected such that the second electric machine 14 and the first electric machine 13 have a minimum speed. As soon as a torque is requested for a purely electric start, the minimum speed is selected such that good efficiency is present for both electric machines 13 and 14 .

[0085] If a torque is then requested for a purely electric start, ie if a purely electric start is to be carried out, a torque is applied to the ring gear 5 of the first planetary gear 2 via the first electric machine 13 , so that the desired starting torque is present at the planet carrier 6 of the first planetary gear 2 .

[0086] The first electric machine 14 , which is operated in the speed control mode, supports this torque at the sun gear 4 of the first planetary gear 2 .

[0087] Since the two electric machines 13 and 14 do not stop but rotate at a minimum speed, unfavorable operating points with high torque and low speed and extreme heating of the respective electric machines and the inverter are avoided. The two electric machines 13 and 14 can be operated in favorable operating points.

[0088] As the driving speed increases during a purely electric EDA start, the speed at the planet carrier 6 of the first planetary gear 2 increases. The speed of the second electric machine 14 can be adapted in order to still ensure favorable speed conditions at both electric machines 13 and 14.

[0089] However, if the gear E1 for the first electric machine 13 is to be engaged from a purely electric EDA start, the speed of the second electric machine 14 is brought to zero or approximately zero in order to synchronize the first form-locking shift element A. The first form-locking shift element A can then be engaged in order to engage Figure 3 Gear position E1.

[0090] The torque of the second electric machine 14 can be reduced, and the first positive-locking shifting element A then automatically assumes the supporting torque on the sun gear 4 of the planetary gear 2. Since the zero or approximately zero speed of the second electric machine 14 is only present for a short time, there is no risk of overheating. The third positive-locking shifting element C can be disconnected without load. The second electric machine 14 can then be used for other functions.

[0091] The advantages of the purely electric EDA start described above are, in particular, that the vehicle can be driven for a longer period of time with high torque and low driving speed without the risk of overheating of the electric machine or the inverter.

[0092] Although it is theoretically possible to use speed control for the first electric machine 13 and to support the torque on the sun gear 4 of the first planetary gear 2 via the first electric machine 13, the above-described distribution of effects between the electric machines 13 and 14 is still preferred during EDA starting. When the above-described distribution of effects between the electric machines 13 and 14 is used during EDA starting, the first electric machine 13 is operated in torque mode both during EDA starting and subsequently when the gear E1 is engaged. Therefore, when changing from a purely electric start to the gear E1 for the first electric machine 13, there is no need to change the speed control and torque control.

[0093] Since the two motors 13 and 14 can change not only the direction of rotation but also the sign of the torque, the method described above can also be used for EDA starting in the reverse direction (see Figure 3 status EDA-R).

[0094] It is also possible to drive purely electrically with the two electric machines 13 and 14 , in which case one of the shift elements A and B and also one of the shift elements D, E, F and G are engaged.

[0095] During a gear change for the second electric machine 14 , traction force can be maintained via the first electric machine 13 . During a gear change for the first electric machine 13 , traction force can be maintained via the second electric machine 14 , more precisely within the specifications of the second electric machine 14 .

[0096] As already mentioned, when the EDS load switching described above or the EDA starting described above is to be used in Figure 2 When the internal combustion engine 15 is in the drive system, the internal combustion engine 15 is decoupled by disengaging the clutch K0.

[0097] exist Figure 2 In the drive system of FIG. 1 , the internal combustion engine 15 can be started by means of the second electric machine 14 , for which purpose the clutch K0 is then closed.

[0098] In addition, Figure 2 In the drive system of , the second electric machine 14 can be used to supply the vehicle with power or to supply the first electric machine 13 for so-called continuous driving. For this purpose, the clutch K0 is also closed and the first shift element A is also closed. The first gear E1 is then engaged for the first electric machine 13. The internal combustion engine 15 and the electric machine 14 have no mechanical connection to the output 9.

[0099] exist Figure 2In the drive system of FIG. 1 , when a gear for the internal combustion engine 15 is to be changed with the clutch K0 closed, the internal combustion engine 15 can be supported by the second electric machine 14 while the speed is synchronized.

[0100] Figure 4 and 5 The drive system and Figure 1 and 2 The drive system is different in one respect: Figure 4 and Figure 5 The first electric machine 13 is directly connected to the ring gear 5 of the first planetary gear transmission 2, and the second planetary gear transmission 3 is connected to the drive system.

[0101] exist Figure 4 and 5 In the example shown in FIG. 1 , when the positive-locking shift element D is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the planet carrier 12 of the second planetary gear 3 . Figure 4 and 5 When the positive locking shift element F in is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the ring gear 11 of the second planetary gear 3. Figure 4 and 5 When the positive-locking shift element E is closed, the planet carrier 12 of the second planetary gear 3 is coupled to the ring gear 5 of the first planetary gear 2 .

[0102] for Figure 4 and 5 For the drive system 1, you can use Figure 6 The gears of the switching matrix are shown in FIG. 1 , wherein gears 2.1 and 2.7 are alternatives for the second gear of the second motor 14 , and gears 3.1 to 3.4 are alternatives for the third gear of the second motor 14 . Gears E1 and E2 are again pure electric gears for the first motor 13 .

[0103] So in Figures 1 to 3 In the embodiment of the invention, the second electric machine 14 and, if necessary, the internal combustion engine 15 can provide four forward gears and additional gears ZG1 and ZG2, while in Figures 4 to 6 In the embodiment of FIG. 3 , three forward gears can be provided. Figure 4 and 5 In the embodiment of the present invention, electric starting in the forward direction can be achieved via the state EDA-V in the forward direction.

[0104] Figure 6 The switching matrix also applies to Figure 7 and 8 drive system. Figure 7 and 8 The drive system 1 and Figure 4 and 5 The drive system 1 is different from the drive system 1 in that the second planetary gear transmission 3 is connected to the drive system. Figure 7 and 8 In FIG. 1 , when the form-locking shift element F is closed, the planet carrier 12 of the second planetary gear 3 is coupled to the ring gear 5 of the first planetary gear 2. When the form-locking shift element E is closed, the planet carrier 12 of the second planetary gear 3 is coupled to the sun gear 10 of the second planetary gear. When the form-locking shift element D is closed, the sun gear 10 of the second planetary gear 3 is fixedly braked relative to the housing.

[0105] In separate use Figure 6 The switching matrix Figure 4 , 5 , 7 and 8 drive systems, you can use the reference Figures 1 to 3 The method involves the EDS load shifting described in the exemplary embodiment of FIG. 2 and the purely electric EDA start in the forward driving direction. The shifting elements A, B and C and the first planetary gear 2 are involved in the method.

[0106] Fig. 9 and 10 A further drive system 1 is shown, in which the method described above can be used in the same manner. The shift elements A, B and C and the first planetary gear 2 are again involved in the method. Fig. 9 and 10 The drive system 1 uses Fig.11 The switching matrix.

[0107] exist Fig. 9 and 10 In the drive system of the first planetary gear 2, the first electric machine 13 is directly coupled to the ring gear 5 of the second planetary gear 2. The planet carrier 6 of the first planetary gear 2 is coupled to different components of the drive system depending on the switching positions of the switching elements B, D and F. When the switching element B is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the sun gear 4 of the first planetary gear 2. When the switching element D is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the planet carrier 12 of the second planetary gear 3. When the switching element F is closed, the planet carrier 6 of the first planetary gear 2 is coupled to the ring gear 11 of the second planetary gear 2. When the third switching element C is closed, the ring gear 11 of the second planetary gear 3 is coupled to the sun gear 4 of the first planetary gear 2.

[0108] according to Fig.11, gears 1 to 3 and an additional gear ZG are available for the second electric machine 14 and, if necessary, the internal combustion engine 15, wherein alternatives 2.1 to 2.5 are available for the second gear and alternatives 3.1 to 3.5 are available for the third gear. For the first electric machine 13, two gears E1 and E2 and a state EDA-V for purely electric starting in the forward direction are available.

[0109] The EDS load switching described above and the electric start in the forward direction described above can be used in the same manner. Fig. 9 and 10 in the drive system.

[0110] Likewise, the described EDS load switching and the described EDA start in the forward direction are Fig.12 and 13 The drive system 1 is used, which uses Fig.14 The switching matrix. Fig.12 and 13 In the drive system of FIG. 1 , three forward gears are provided for the second electric machine 14 and, if necessary, for the internal combustion engine 15 , and the electric gears E1 and E2 as well as the operating state EDA-V can be used for the first electric machine 13 .

[0111] exist Fig.12 and 13 In the drive system of FIG. 1 , the first motor 13 is not directly coupled to the ring gear of the first planetary gear transmission 2, but is indirectly coupled via a fixed pre-gear ratio provided by the second planetary gear transmission 3. The sun gear 10 of the second planetary gear transmission 3 is Fig.12 and 13 Fixedly connected relative to the housing. The ring gear 11 of the second planetary gear transmission 3 is coupled to the drive shaft 7. The planet carrier 12 of the second planetary gear transmission 3 is connected to the ring gear 5 of the first planetary gear transmission 2. When the switching element E is closed, the ring gear 11 of the second planetary gear transmission 3 is coupled to the second motor 14. When the switching element F is closed, the planet carrier 12 of the second planetary gear transmission 3 and the ring gear 5 of the first planetary gear transmission 2 are coupled to the second motor 14. When the switching element D is closed, the planet carrier 6 of the first planetary gear transmission 2 is coupled to the second motor 14.

[0112] Reference numerals list

[0113] 1. Drive system

[0114] 2 First planetary gear transmission

[0115] 3 Second planetary gear transmission

[0116] 4 Sun gear of the first planetary gear

[0117] 5 Ring gear of the first planetary gear

[0118] 6 Planet carrier of the first planetary gear

[0119] 7 First drive shaft

[0120] 8 Second drive shaft

[0121] 9 Driven shaft

[0122] 10 Sun gear of the first planetary gear

[0123] 11 Ring gear of the first planetary gear

[0124] 12 Planet carrier of the first planetary gear

[0125] 13 First Motor

[0126] 14 Second Motor

[0127] 15 Internal combustion engine

[0128] A First positive-locking shifting element

[0129] B Second form-locking shifting element

[0130] C Third form-locking shifting element

[0131] D Fourth form-locking shift element

[0132] E Fifth positive-locking shifting element

[0133] F Sixth positive-locking shift element

[0134] G Seventh form-locking shifting element

[0135] K0 Clutch

Claims

1. A method for operating a drive system of a motor vehicle, in, The drive system comprises a first planetary gear transmission (2), the first planetary gear transmission having a sun gear (4), a ring gear (5) and a planet carrier (6), The sun gear (4) of the first planetary gear (2) can be fixedly braked on the housing side via a first positive-locking shift element (A). The sun gear (4) of the first planetary gear (2) can be coupled to the planet carrier (6) of the first planetary gear (2) via a second positive-locking shift element (B) while providing an integral rotation on the first planetary gear (2). The drive system comprises a first electric machine (13), which is coupled to the ring gear (5) of the first planetary gear (2) either directly or indirectly via a second planetary gear (3). The drive system has a second electric machine (14) which can be coupled to the sun gear (4) of the first planetary gear (2) via a third positive-locking shift element (C) either directly or indirectly via the second planetary gear (3). In order to implement a load switch from a first gear for a first electric machine (13) to a second gear for the first electric machine (13) during pure electric driving, at least the following steps are performed: Firstly, the second electric machine (14) is coupled to the sun gear (4) of the first planetary gear (2) via the third form-locking shift element (C). Then, the positive locking switching elements (A, B) to be engaged for load switching are unloaded via the second motor (14). Subsequently, the form-locking switching elements (A, B) to be hung out for load switching are hung out. Next, the form-locking switching elements (B, A) to be engaged for load switching are synchronized. Subsequently, the form-locking switching elements (B, A) to be engaged for load switching are engaged. Among them, in order to implement traction upshift load switching, As the form-locking shifting element to be suspended, the first form-locking shifting element (A) is relieved of load and then suspended, As the form-locking shifting element to be engaged, the second form-locking shifting element (B) is synchronized via an integral rotation on the first planetary gear (2) and then engaged, wherein, in order to synchronize the second form-locking shifting element (B) to be engaged, the torque applied by the first motor (13) is reduced and the torque applied by the second motor (14) is increased; or among them, In order to implement push-down load switching, As the form-locking shifting element to be suspended, the second form-locking shifting element (B) is relieved of load and then suspended, As the form-locking shifting element to be engaged, the first form-locking shifting element (A) is synchronized by braking the sun gear (4) of the planetary gear (2) to a rotational speed of zero or approximately zero and then engaged, In order to synchronize the first positive-locking shift element (A) to be engaged, the torque applied by the first electric machine (13) is reduced in value and the torque applied by the second electric machine (14) is increased in value.

2. The method according to claim 1, characterized in that After the positive-locking shift element to be engaged for load switching is engaged, the second electric machine (14) is decoupled from the sun gear (4) of the first planetary gear (2) via the third positive-locking shift element (C).

3. The method according to claim 1, characterized in that In order to synchronize the second form-locking shifting element (B) to be engaged, the torque applied by the first electric machine (13) is reduced and the torque applied by the second electric machine (14) is increased, so that the total power applied by the two electric machines (13, 14) remains constant or approximately constant.

4. The method according to claim 1, characterized in that In order to synchronize the first positive-locking shifting element (A) to be engaged, the torque applied by the first electric machine (13) is reduced in value and the torque applied by the second electric machine (14) is increased in value, so that the total power applied by the two electric machines (13, 14) remains constant or approximately constant.

5. A method for operating a drive system of a motor vehicle, in, The drive system comprises a first planetary gear transmission (2), the first planetary gear transmission having a sun gear (4), a ring gear (5) and a planet carrier (6), The sun gear (4) of the first planetary gear (2) can be fixedly braked on the housing side via a first positive-locking shift element (A). The sun gear (4) of the first planetary gear (2) can be coupled to the planet carrier (6) of the first planetary gear (2) via a second positive-locking shift element (B) while providing an integral rotation on the first planetary gear (2). The drive system comprises a first electric machine (13), which is coupled to the ring gear (5) of the first planetary gear (2) either directly or indirectly via a second planetary gear (3). The drive system has a second electric machine (14) which can be coupled to the sun gear (4) of the first planetary gear (2) via a third positive-locking shift element (C) either directly or indirectly via the second planetary gear (3). In order to start the vehicle with pure electric power, at least the following steps are required: Firstly, the second electric machine (14) is coupled to the sun gear (4) of the first planetary gear (2) via the third form-locking shift element (C). Subsequently, when or after a request for a starting torque is made, a torque is applied to the ring gear (5) of the first planetary gear (2) via the first electric machine (13), and the second electric machine (14) is operated in a speed control mode in such a way that the second electric machine (14) supports the torque on the sun gear (4) of the second planetary gear (2).

6. The method according to claim 5, characterized in that When the starting speed increases and the first motor (4) is to be engaged in the first gear, Firstly, the speed of the second electric machine (14) is brought to zero or approximately zero in order to synchronize a first positive-locking shift element (A) to be engaged for the first gear. Next, the first form-locking shifting element (A) to be mounted is mounted. Subsequently, the torque applied by the second electric machine (14) is reduced and the third form-locking shift element (C) is opened in order to decouple the second electric machine (14) from the sun gear (4) of the first planetary gear (2).

7. The method according to any one of claims 1 to 6, characterized in that If the drive system has an internal combustion engine (15) in addition to the first electric machine (13) and the second electric machine (14), the internal combustion engine (15) is decoupled and / or remains decoupled for carrying out the method.

8. The method according to any one of claims 1 to 6, characterized in that When the drive system has a second planetary gear (3) in addition to the first planetary gear (2), the second electric machine (14) is either fixedly connected to a rotatable element of the second planetary gear (3) or can be coupled to the rotatable element of the second planetary gear (3) via at least one further form-locking switching element (E, F).

9. The drive system of motor vehicles, The drive system comprises a first planetary gear transmission (2), the first planetary gear transmission having a sun gear (4), a ring gear (5) and a planet carrier (6), in, The sun gear (4) of the first planetary gear (2) can be fixedly braked on the housing side via a first positive-locking shift element (A). wherein the sun gear (4) of the first planetary gear (2) can be coupled to the planet carrier (6) of the first planetary gear (2) via a second positive-locking shift element (B) while providing an integral rotation on the first planetary gear (2), The drive system has a first electric motor (13), which is directly coupled to the ring gear (5) of the first planetary gear (2). The drive system has a second electric machine (14) which can be coupled to the sun gear (4) of the first planetary gear (2) via a third positive-locking shift element (C) either directly or indirectly via a second planetary gear (3).

10. The drive system according to claim 9, characterized in that: The drive system comprises, in addition to the first planetary gear (2), a second planetary gear (3), wherein the second electric machine (14) is either fixedly connected to a rotatable element of the second planetary gear (3) or can be coupled to the rotatable element of the second planetary gear (3) via at least one further form-locking shifting element (E, F).

Images