CN115703339A - Cooling circulation system for electrified drive train - Google Patents

Abstract

The invention relates to a cooling circuit for a P2 hybrid module, having at least two cooling circuits, but no actuator to be operated, having two electric pumps and a check valve, wherein at least one electric pump is reversible and the check valve is only passive, i.e. not electromagnetically operated. The invention is characterized in that the check valves are interconnected in such a way that one of the pumps can assist the other pump in feeding the cooling circuit by feeding in coolant.

Description

Cooling circulation system for electrified drive train

Technical Field

The invention relates to a cooling circuit for cooling an electrified drive train of a motor vehicle, in particular a P2 hybrid module for use in a drive train of a motor vehicle.

Background

A hybrid module is understood to be an assembly which comprises a plurality of parts of a hybrid drive of a motor vehicle, which are constructed as a module and can therefore be flexibly installed in a plurality of drive trains. In particular, such hybrid modules also comprise an electric motor which serves as a torque source in the hybrid drive train (in addition to the internal combustion engine), i.e. supplies torque to the drive of the motor vehicle. For example, in a coaxial P2 hybrid module, at least two electric pumps (E-Pump) must be used to supply cooling medium, in particular cooling oil, to the following components: an electric Motor (E-Motor) (particularly a stator of an electric Motor); clutch K0 (disconnect clutch for disconnecting the internal combustion engine from the rest of the drive train)/K1 (first clutch of the dual clutch), K0 and K1 being in particular radially nested; the clutch K2 (second clutch of the dual clutch) and the gear mechanism or gearbox with bearings and/or gearing, for example, comprise two axially displaceable cone disk pairs and a traction means running between the cone disk pairs. Each component is divided into two cooling circuits.

In principle, the two electric pumps together provide a sufficient volumetric flow of cooling oil in order to cool the clutch K1 or the clutch K2, respectively, sufficiently at the start, but each electric pump alone cannot provide sufficient cooling efficiency for the currently active clutch.

Disclosure of Invention

On this basis, it is an object of the present invention to at least partly overcome the problems known in the prior art.

This object is achieved by the features of the independent claim 1. Further advantageous embodiments of the invention are given in the dependent claims. The features listed individually in the dependent claims can be combined with one another and can define further embodiments of the invention. The features specified in the claims are also described and explained in detail in the description, in which further preferred embodiments of the invention are shown.

The invention proposes that the two electric pumps are connected by means of passive, i.e. non-electromagnetically actuated check valves in such a way that one of the electric pumps can assist the other electric pump in cooling the currently active clutch (K1 or K2) of the cooling circuit or the component to be cooled, wherein at least one electric pump is reversible. The maximum cooling volume is used for the clutch K1 and the clutch K2 (at start-up). Furthermore, a branch with a throttle for cooling the bearing and the stator of the electric motor is preferred. The clutch K0 may be arranged in series with the clutch K1 such that the cooling oil first flows through the clutch K0 and then to the clutch K1, thus being supplied with the cooling oil. Instead, only a predefinable portion, for example one third, is bypassed to the clutch K0 via a bypass and then fed again to K1 in order to reduce the drag torque when the clutch K0 is open.

The cooling circuit according to the invention for an electrified drive train, in particular for use in a motor vehicle, comprises at least two cooling circuits, including

-the components to be cooled being distributed to two cooling circuits,

-two electric pumps, at least one of which is reversible, and

check valves arranged such that each electric pump can be connected with at least one cooling circuit,

characterized in that the check valves are associated such that at least one of the electric pumps can assist the respective other electric pump in supplying coolant to the cooling circuit.

The term electrified drive train is understood here to mean: the electrified drive train comprises at least one electric motor for providing torque to a drive of the motor vehicle. In particular, the electrified drive train comprises a hybrid drive train comprising an internal combustion engine and at least one electric motor for providing torque, and an electric drive train comprising only the at least one electric motor for providing torque. In particular, the electrified drive train can also comprise a hybrid module, which can be cooled by the cooling circuit according to the invention.

A hybrid module is understood to be an assembly which comprises elements of a hybrid drive for a motor vehicle, in particular an electric motor for providing torque to the drive of the motor vehicle. The P2 hybrid module is understood as: the electric motor is mounted in the transmission unit and the hybrid module comprises in particular at least one clutch, in particular at least one separating clutch for separating and connecting the internal combustion engine from the drive train of the motor vehicle.

An electric drive train is understood to be a drive train which comprises at least one electric motor for providing a torque and optionally at least one of the following components: the transmission is used in particular for actuating actuators of parking locks and/or separating elements and/or for operating power electronics of at least one electric motor.

The term cooling circuit is understood to mean a line and a cooling element, which can be flowed through by a coolant and can remove heat from the component to be cooled, the line and the cooling element being thermally connected to the cooling circuit. The term electric pump is understood to mean a pump which has an electric motor as drive. The term reversible is understood to mean: the conveying direction of the pump can be reversed, i.e. the pump can be operated in two opposite conveying directions.

A non-return valve is understood to be a pressurized valve which is closed in one direction by a force exerted, for example, by a spring and which is released in the other direction by the pressure of the flowing fluid. If there is pressure in the direction of passage of the non-return valve, this pressure can relieve the throughflow through the non-return valve against this force. In the check valve, actuation, for example by an actuator, may be eliminated. The check valve as used herein is passive, i.e. there is no actuator for operating the check valve.

The cooling cycle system according to the present invention has two electric pumps. Each pump is assigned to a cooling circuit and supplies cooling power to the cooling circuit by supplying coolant. In the case of a non-reversible electric pump, this corresponds to the operation of an electric pump having only one delivery direction. In reversible electric pumps, this corresponds to operation in one of two possible conveying directions. If the reversible electric pump is operated in a second conveying direction, which is opposite to the first conveying direction, the coolant is conveyed into the other cooling circuit, thus assisting the further electric pump. Thus, with the cooling circuit according to the invention, for example when the clutch assigned to the cooling circuit starts to start, a higher cooling circuit in one cooling circuit can be covered at the same time by the additional pump.

Preferably, the two electric pumps are constructed to be reversible. This enables an efficient design of the cooling circulation system, since the peaks of the cooling demand generated in the two cooling circuits can be covered by the two electric pumps, while the basic demand of one cooling circuit can be covered by the single pump. In particular, if the K1 and K2 clutches are assigned to different cooling circuits, the cooling circuit can now be designed in an efficient and energy-saving manner for the pump.

Preferably, the at least one reversible electric pump is connected directly to one cooling circuit and to the other cooling circuit via a bypass line. This enables the cooling circulation system to be designed in a simple manner in terms of equipment.

Preferably, the component to be cooled is selected from the following components:

-a disconnect clutch for reversibly disconnecting the internal combustion engine from the drive train;

-a first clutch of the dual clutch,

-a second clutch of the double clutch,

-a transmission;

-at least one bearing, in particular of an electric motor;

-an electric motor for providing a torque to a drive of the motor vehicle; and

-at least one power electronic device.

Preferably at least two of the components are selected. In particular, at least the separating clutch, the first clutch and the second clutch are selected. Preferably, the first separating clutch is assigned to the first cooling circuit and the second separating clutch is assigned to the second cooling circuit. The first and second clutches have the greatest cooling requirement at the start, whereby it is advantageous to assign each of them to its own cooling circuit, so that peaks in the cooling requirement can be covered via at least one reversible electric pump. This is particularly advantageous since only one of the first clutch and the second clutch may have a peak in the cooling demand, since only one of the two clutches is used for starting at a specific point in time. Preferably, the separating clutch is also assigned to the first cooling circuit. Preferably, the separating clutch and the first clutch are arranged in series in the first cooling circuit such that the coolant flows first through the separating clutch and then through the first clutch. This makes it possible to effectively cool the separation clutch and the first clutch.

A throttle is preferably provided, by means of which the volumetric flow of the coolant can be preset for the component. If a plurality of components are assigned to a cooling circuit, the distribution of the coolant in the cooling circuit can advantageously be preset by the formation of the throttle. For example, the cooling requirement of the bearings is low, whereas the cooling requirement of the clutch is high, in particular when the clutch is closed, for example when the motor vehicle is started. By forming a flow-technically restrictive portion before the bearing, a volumetric flow of the coolant can be defined for the bearing. Preferably, the throttle is used in a parallel arrangement of the components, so that only the volume flow is throttled for these components.

Preferably, an electric motor capable of generating torque for a drive of the motor vehicle is assigned to both cooling circuits. It is therefore possible to meet high cooling demands by means of two cooling circuits when the electric motor is operated in the high load range. This simplifies the design of the cooling circuit, wherein the electric pump is designed such that the maximum cooling power of the component to be cooled and the basic cooling power of the component to be cooled can be efficiently provided.

It should be noted as a precautionary measure that the ordinal numbers ("first", "second", ".,.) used here are primarily (only) used to distinguish a plurality of similar objects, variables or processes, i.e. the relevance and/or the order of these objects, variables or processes to one another is not in particular mandatory. Where a dependency and/or order is required, it may be explicitly stated herein or will be apparent to one of ordinary skill in the art in view of the specifically described embodiments.

Drawings

The invention and the technical field are explained in detail below with reference to the drawings. It should be noted that the present invention should not be limited by the illustrated embodiments. Particularly if not explicitly indicated to the contrary, may also be extracted from and combined with other elements and realizations in the present description and/or in the drawings. It should be noted in particular that the drawings and the dimensional ratios shown in particular are purely schematic. The same reference numerals denote the same objects so that the explanations in other drawings may be used as supplementary if necessary. In which is shown:

FIG. 1 shows a schematic view of a first embodiment of a cooling cycle system;

FIG. 2 shows a schematic view of a second embodiment of a cooling cycle system;

FIG. 3 shows a detail view of a second embodiment of a cooling cycle system; and

fig. 4 shows a schematic view of a hybrid module with components to be cooled.

Detailed Description

Fig. 1 shows a schematic illustration of a first exemplary embodiment of a cooling circuit 1 for a P2 hybrid module, not shown, as an exemplary embodiment of an electrified drive train of a motor vehicle. The cooling circulation system 1 includes a first electric pump 2 having a first electric motor 3 for driving the pump 2. The first electric pump 2 is connected via a first supply line 4 to a reservoir 5 for coolant, in particular for lubricant, in particular for oil. The first electric pump 2 is of the non-reversible type, i.e. it can only be operated in the conveying direction 9, so that coolant is conveyed from the reservoir 5 to the first cooling circuit 6.

Furthermore, the cooling circuit 1 also comprises a second electric pump 7 having a second electric motor 8 for driving the pump 7. The second electric pump 7 is reversible, i.e. it can be operated in a first conveying direction 12 and a second conveying direction 13, which is opposite to the first conveying direction 12. The second electric pump 7 is connected to the reservoir 5 via a second inlet line 10. The second cooling circuit 11 can be supplied with coolant via the second electric pump 7.

The second supply line 10 is connected to a first line 14 and a second line 15. The reservoir 5 is connected to the second cooling circuit 11 via a first line 14 and a second supply line 10, and the reservoir 5 is connected to the first cooling circuit 6 via a second line 15 and a second supply line 10.

In the first line 14, a first check valve 16 and a second check valve 17 are formed, which allow the coolant to flow from the reservoir 5 to the second cooling circuit 11, respectively, but do not flow in the opposite direction. The second electric pump 7 is connected to the first line 14 between a first check valve 16 and a second check valve 17.

In the second line 15, a third check valve 18 and a fourth check valve 19 are formed, which each allow a flow of coolant from the reservoir 5 in the direction of the first cooling circuit 6, but not in the opposite direction. The second electric pump 7 is connected to the second line 15 between the third check valve 18 and the fourth check valve 19. At the same time, the third check valve 18 prevents flow from the reservoir 5 to the second electric pump 7 by the first electric pump 2.

If the second electric pump 7 is operated in the first conveying direction 12, the coolant is conveyed from the reservoir 5 via the second inlet line 10, the second line 15, the fourth check valve 19, the first check valve 16 in the first line 14 to the second cooling circuit 11. The third check valve 18 simultaneously prevents coolant from flowing from the second inlet line 10 to the first cooling circuit 6. The second non-return valve 17 prevents the coolant from flowing back in the direction of the reservoir 5.

If the second electric pump 7 is operated in the second conveying direction 13, the coolant is conveyed from the reservoir 5 via the second supply line 10 into the first line 14 and through the second check valve 17 into the second line 15 and from there through the third check valve 18 via the first bypass line 20 to the first cooling circuit 6. If the first electric pump 2 is running simultaneously, the second electric pump 7 assists the first electric pump 2 in delivering coolant to the first cooling circuit 6. At the same time, the first check valve 16 interrupts the flow in the direction of the second cooling circuit 11 and the fourth check valve 19 interrupts the return flow into the reservoir 5.

Fig. 2 shows a schematic view of a second embodiment of the cooling circuit 1. In order to avoid repetitions, only the differences from the first exemplary embodiment are explained here, otherwise reference is made to the above-described embodiments of the first exemplary embodiment. In contrast to the first exemplary embodiment, in the second exemplary embodiment the first electric pump 2 is also of reversible design, so that it can be transported in both the first transport direction 12 and the second transport direction 13, which is oriented opposite to the first transport direction 12.

The first inlet line 4 also branches into a third line 21 and a fourth line 22. In the third line 14, a fifth check valve 23 and a sixth check valve 24 are formed, which respectively allow the coolant to flow from the reservoir 5 to the second cooling circuit 11 via a second bypass line 25, but not in the opposite direction. Here, the first electric pump 2 is connected to the third line 21 between the fifth check valve 23 and the sixth check valve 24.

In the fourth line 22, a seventh check valve 26 and an eighth check valve 27 are formed, which respectively allow the coolant to flow from the reservoir 5 to the first cooling circuit 6, but not in the opposite direction. Here, the first electric pump 2 is connected to the fourth line passage 22 between the seventh check valve 26 and the eighth check valve 27.

If the first electric pump 2 is operated in the first conveying direction 12, the coolant is conveyed from the reservoir 5 via the first inlet line 4, the fourth line 22, the eighth check valve 27, the fifth check valve 23 in the third line 21 via the second bypass line 25 to the second cooling circuit 11. The sixth check valve 24 prevents the coolant from flowing back in the direction of the reservoir 5.

If the first electric pump 2 is operated in the second conveying direction 13, the coolant is conveyed from the reservoir 5 via the first supply line 4 into the third line 21 and through the sixth non-return valve 24 into the fourth line 22 and from there through the seventh non-return valve 26 into the first cooling circuit 6.

Thus, by operating the first electric pump 2 in the first conveying direction 12, it is possible to convey coolant from the reservoir 5 to the second cooling circuit 11, thus assisting the second electric pump 7 in the cooling of the first cooling circuit 11. At the same time, cooling power can be supplied to the first cooling circuit 6 by operation of the first electric pump 2 and assistance is enabled by operation of the second electric pump 7 in the second conveying direction 13.

In the first exemplary embodiment, the control of the cooling performance of the first cooling circuit 5 and/or of the second cooling circuit 11 is effected by selecting the rotational speed of the first electric motor 3 for the first electric pump 2 and the rotational speed of the second electric motor 3 and the delivery direction 12, 13 for the second electric pump 7. With the second exemplary embodiment, the control of the cooling power of the first cooling circuit 5 and/or of the second cooling circuit 11 is effected by selecting the rotational speed and the delivery direction 12, 13 of the first electric motor 3 for the first electric pump 2 and the rotational speed and the delivery direction 12, 13 of the second electric motor 3 for the second electric pump 7. In both embodiments, the non-return valves 16, 17, 18, 19, 23, 24, 26, 27 allow for control by passive valves without the need to externally actuate the respective valves.

Thus, fig. 1 and 2 show a principle wiring scheme commonly used to assist the first electric pump 2 by the second electric pump 7, wherein the commutation of the electric pumps 2, 7 is used to control which paths the cooling oil (coolant) should run on.

Fig. 1 shows a variant with only one reversible pump, and fig. 2 shows a variant with two structurally identical reversible pumps. The cooling circuits, to which a plurality of components to be cooled or a plurality of components to be cooled are assigned, are designated by reference numerals 6 (also "Cool 1") and 11 (also "Cool 2"). "Cool1" can comprise, for example, K0 and K1, i.e. the separating clutch K0 and the first clutch K1 of the dual clutch transmission, and "Cool 2" can comprise K2 (second clutch K2 of the dual clutch transmission) and the transmission cooling and the stator of the electric drive (electric motor) of the hybrid drive of the motor vehicle. The distribution of the cooling circuits "Cool1" (reference 6) and "Cool 2" (reference 11) can be adjusted as required.

Fig. 3 shows a variant of fig. 2, in which the cooling circuit 6, 11 is broken down into the components to be cooled, including the branches for the bearings and the electric motor via the throttle. The electric machine is supplied with coolant by two cooling circuits. In particular, fig. 3 shows a cooling circuit 1, which corresponds to the second embodiment according to fig. 2. In order to avoid repetition, only the differences from fig. 2 are explained here, and reference is otherwise made to the above-described embodiment of fig. 2. In addition to the at least one further component 28 to be cooled, the first cooling circuit 6 also comprises, in particular, an electric Motor 29 (E-Motor), which serves as a torque source in a hybrid drive train of the Motor vehicle. The second cooling circuit 11 comprises, in addition to at least one further component 30 to be cooled, an electric motor 29 and a bearing 31, which is likewise supplied with coolant in the second cooling circuit 11. The electric motor 29 is part of both cooling circuits 6, 11. The components 28, 30 to be cooled preferably comprise a K0 clutch and a K1 clutch for the first cooling circuit 6 and a K2 clutch for the second cooling circuit 11. A throttle 32 is also provided, via which the flow ratio to the individual components, in particular the volume flow of the coolant, can be preset.

Fig. 4 schematically shows a P2 hybrid module 33 with a separating clutch (K0) 34, an electric motor 29, a first clutch (K1) 35 of a dual clutch 36, which also has a second clutch (K2) 37. The elements of the P2 hybrid module 33 are distributed to the first cooling circuit 6 and/or the second cooling circuit 11 as described above.

The cooling circuit system 1 is used for a P2 hybrid module 33, the cooling circuit system 1 having at least two cooling circuits 6, 11 and no actuators to be operated, the cooling circuit system 1 comprising two electric pumps 2, 7 and check valves 16, 17, 18, 19, 23, 24, 26, 27, wherein at least one electric pump is reversible and the check valves are only passive, i.e. non-electromagnetically operated. The invention is characterized in that the non-return valves 16, 17, 18, 19, 23, 24, 26, 27 are interconnected in such a way that one of the pumps 2, 7 can assist the other pump in supplying the cooling circuit 6, 11 by feeding in coolant.

List of reference numerals

1. Cooling circulation system

2. Electrically driven first pump

3. First motor

4. First input pipeline

5. Storage device

6. First cooling circuit

7. Electrically driven second pump

8. Second motor

9. Direction of conveyance

10. Second input pipeline

11. Second cooling circuit

12. First conveying direction

13. Second conveying direction

14. First pipeline circuit

15. Second pipeline circuit

16. First check valve

17. Second check valve

18. Third check valve

19. Fourth check valve

20. First bypass pipeline

21. Third pipeline circuit

22. Fourth pipeline

23. Fifth check valve

24. Sixth check valve

25. Second bypass line

26. Seventh check valve

27. Eighth check valve

28. Component to be cooled

29. Electric motor

30. Component to be cooled

31. Bearing assembly

32. Throttle part

33 P2 hybrid power module

34. Separation clutch (K0)

35. First clutch (K1)

36. Double clutch

37. Second clutch (K2)

Claims (6)

1. Cooling circuit (1) for an electrified drive train, in particular for use in a motor vehicle, having at least two cooling circuits (6, 11), comprising

-components (28, 29, 30, 31, 32) to be cooled which are assigned to the two cooling circuits (6, 11),

-two electric pumps (2, 7), at least one of which is reversible, and

-check valves (16, 17, 18, 19, 23, 24, 26, 27) arranged such that each of the electric pumps (2, 7) is connectable with at least one cooling circuit (6, 11),

characterized in that the check valves (16, 17, 18, 19, 23, 24, 26, 27) are associated such that at least one of the electric pumps (2, 7) can assist the respective other electric pump (7, 2) in supplying coolant to the cooling circuit (6, 11).

2. Cooling cycle system (1) according to claim 1, wherein the two electric pumps (2, 7) are reversibly constructed.

3. Cooling cycle system (1) according to one of the preceding claims, wherein at least one reversible electric pump (2, 7) is directly connected with one cooling circuit (6, 11) and with the other cooling circuit (11, 6) via a bypass line (20, 25).

4. Cooling cycle system (1) according to any of the preceding claims, wherein the component (28, 30) to be cooled is selected from the following components:

-a disconnect clutch (34) for reversibly disconnecting the internal combustion engine from the drive train;

a first clutch (35) of a dual clutch (36),

a second clutch (37) of the dual clutch (36),

-a transmission;

-at least one bearing (31), in particular of an electric motor (29);

-an electric motor (29) for providing a torque to a drive of the motor vehicle; and

-at least one power electronic device.

5. Cooling circuit system (1) according to one of the preceding claims, wherein a throttle (32) is configured, by means of which a volume flow of the coolant can be preset for the component (28, 29, 30, 31, 32) to be cooled.

6. Cooling cycle system (1) according to any of the preceding claims, wherein an electric motor (29) capable of generating torque for a drive of a motor vehicle is distributed to both cooling circuits (6, 11).

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