ELECTRIFIED DRIVE TRAIN HAVING A HEAT EXCHANGER ASSEMBLY IN A COOLING CIRCUIT, AND ELECTRIC VEHICLE HAVING A DRIVE TRAIN

Abstract

An electrified drive train for a motor vehicle has a heat generator, which includes at least one electric drive machine; and a cooling circuit, which is led through the electric drive machine and has a heat exchanger for removing heat from the cooling circuit. With respect to the direction of flow of the fluid used in the cooling circuit, the heat exchanger is arranged in the cooling circuit downstream of the heat generator to be cooled.

Claims

1. An electrified drive train for a motor vehicle, comprising: a heat generator, which comprises at least one electric drive machine, and a cooling circuit, which is led through the electric drive machine and has a heat exchanger for removing heat from the cooling circuit, wherein, with respect to a direction of flow of fluid used in the cooling circuit, the heat exchanger is arranged in the cooling circuit downstream of the heat generator to be cooled.

2. The electrified drive train according to claim 1, wherein the heat exchanger is arranged directly downstream of the heat generator to be cooled.

3. The electrified drive train according to claim 1, wherein the heat generator is the electric drive machine or a secondary unit, such as a power electronics and/or a clutch and/or a gearbox.

4. The electrified drive train according to claim 1, wherein the drive train has a plurality of heat generators to be cooled, wherein the heat exchanger is arranged downstream of the heat generator to be cooled having the greatest heat generation.

5. The electrified drive train according to claim 4, wherein, in addition to the heat exchanger arranged downstream of the heat generator having the greatest heat generation, a further heat exchanger is arranged in the cooling circuit for dividing a cooling capacity, wherein the further heat exchanger is arranged upstream of the heat generator having the greatest heat generation.

6. The electrified drive train according to claim 1, wherein a volume flow of the cooling circuit is divided into partial volume flows which run parallel to one another.

7. The electrified drive train according to claim 6, wherein the volume flow has a partial volume flow for cooling a gearbox and/or a partial volume flow for cooling a clutch.

8. The electrified drive train according to claim 6, wherein the cooling circuit has a hydraulic resistance arranged in the volume flow for adjusting a flow rate of the partial volume flows.

9. The electrified drive train according to claim 3, wherein the drive train has the cooling circuit led through the electric drive machine and a second cooling circuit led through the power electronics, wherein the heat exchanger of the cooling circuit is arranged downstream of the electric drive machine and a heat exchanger of the second cooling circuit is arranged downstream of the power electronics.

10. An electric vehicle comprising: an electrified drive train including a heat generator, which comprises at least one electric drive machine, a pooling circuit, which is led through the electric drive machine and has a heat exchanger for removing heat from the cooling circuit, wherein, with respect to a direction of flow of fluid used in the cooling circuit, the heat exchanger is arranged in the cooling circuit downstream of the heat generator to be cooled.

11. An electrified drive train for a motor vehicle, comprising: a heat generator having at least one electric drive machine; and a cooling circuit led through the electric drive machine and having a heat exchanger for removing heat from the cooling circuit, wherein a volume flow of the cooling circuit is divided into partial volume flows which run parallel to one another, wherein the volume flow has a partial volume flow for cooling a gearbox and a partial volume flow for cooling a clutch.

12. The electrified drive train for a motor vehicle according to claim 11, wherein, with respect to a direction of flow of fluid used in the cooling circuit, the heat exchanger is arranged in the cooling circuit downstream of the heat generator to be cooled.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The disclosure is explained below with the aid of drawings. In the figures:

[0033] FIG. 1 shows a schematic representation of a part of a cooling circuit according to the disclosure in a first embodiment,

[0034] FIG. 2 shows a schematic representation of another part of the cooling circuit according to the disclosure,

[0035] FIG. 3 shows a schematic representation of a heat removal circuit according to the disclosure in a first embodiment,

[0036] FIG. 4 shows a schematic representation of a heat removal circuit according to the disclosure in a second embodiment

[0037] FIG. 5 shows a schematic representation of a heat removal circuit according to the disclosure in a third embodiment,

[0038] FIG. 6 shows a schematic representation of an exemplary heat removal circuit, and

[0039] FIG. 7 shows an example of the basic structure of a cooling system having a cooling circuit and a heat removal circuit.

DETAILED DESCRIPTION

[0040] The figures are only schematic in nature and serve only for understanding the disclosure. The same elements are provided with the same reference symbols. The features of the individual embodiments can be interchanged.

[0041] FIG. 1 schematically shows a first part of a drive train 1 according to the disclosure for a motor vehicle, in particular an electric vehicle. The drive train 1 is electrified. The drive train 1 has a heat generator 2. The heat generator 2 comprises at least one electric drive machine 3 having an electric motor 3. The drive train 1 has a cooling circuit 4 led through the electric drive machine 3. The cooling circuit 4 has a heat exchanger 5 for removing heat from the cooling circuit 4.

[0042] According to the disclosure, with respect to the direction of flow of the fluid used in the cooling circuit 4, in particular oil, the heat exchanger 5 is arranged in the cooling circuit 4 downstream of the heat generator 2 to be cooled. In the cooling circuit 4 shown in FIG. 1, the heat exchanger 5 is arranged downstream of the electric drive machine 3. As a result, a large portion of the heat generated by the electric drive machine 3 can be used as waste heat to heat a passenger compartment.

[0043] The drive train 1 also has one or more secondary units. A secondary unit can be, for example, a power electronics unit 6 (cf. FIG. 2). A secondary unit can be, for example, a first clutch 7 or a second clutch 8. A secondary unit can also, for example, be a gearbox 9. Accordingly, the drive train 1 usually has several heat generators 2 to be cooled. According to the disclosure, the heat exchanger 5 is arranged in particular downstream of the heat generator 2 to be cooled having the greatest heat generation, such as the drive machine 3. In addition, the heat exchanger 5 can be arranged upstream, in particular directly upstream, of the heat generators 2 to be cooled, apart from the heat generator 2 having the greatest heat generation, i.e., in this case the drive machine 3. This allows sufficient cooling capacity to be provided to the other heat generators 2.

[0044] In the embodiment shown, a volume flow 10 of the cooling circuit 4 is divided into partial volume flows that run parallel to one another. The oil is thus drawn from an oil sump 11, preferably via a suction filter 12, by a cooling pump 13. Then the oil of the volume flow 10 is conveyed by the cooling oil pump 13 through the drive machine 3. In the direction of flow behind it, the heat exchanger 5 is flooded. Downstream, the volume flow 10 is divided. A first partial volume flow 14 diverts from the volume flow 10 at a first node 15, which has a lower flow rate than the volume flow 10. Downstream, the volume flow is divided at a second node 16 into a second partial volume flow 17 and a third partial volume flow 18. The first partial volume flow 17 can, for example, be designed to cool the first clutch 7 and/or the second clutch 8. The first partial volume flow 17 can, for example, be designed to cool the gearbox 9. Preferably, the flow rate of the first partial volume flow 14 and the flow rate of the second partial volume flow 17 and the third partial volume flow 18 together are substantially equal.

[0045] A hydraulic resistance 19 is arranged in the volume flow 10 for adjusting the flow rate of the partial volume flows. In the embodiment shown, a hydraulic resistance 19 is arranged in each of the three partial volume flows 14, 17, 18. In the embodiment shown, the hydraulic resistance 19 is designed as a passive adjusting element 20. The hydraulic resistance 19 can also be designed as an active adjusting element, even though this is not shown in FIG. 1.

[0046] Thus, according to the disclosure, the drive train 1 has the cooling circuit 4 led through the electric drive machine 3, in which the heat exchanger 5 of the cooling circuit 4 is arranged downstream of the electric drive machine 3.

[0047] FIG. 2 shows another part of the drive train 2. FIG. 2 shows a second cooling circuit 21 led through the power electronics unit 6. A heat exchanger 22 of the second cooling circuit 21 is arranged downstream, preferably directly downstream, of the power electronics unit 6 in the direction of flow of the cooling fluid. This allows the waste heat from the power electronics unit to be utilized. In the second cooling circuit 21, the oil is drawn from the oil sump 11, preferably via a suction filter 23, by a cooling pump 24. Then the oil is conveyed through the power electronics unit 6 by the cooling oil pump 24. In the direction of flow behind it, the heat exchanger 22 is flooded.

[0048] FIGS. 3 to 6 show schematic representations of a heat removal circuit 25 of the drive train 1 according to the disclosure. In particular, the FIGS. 3 to 5 show the structure of the heat removal circuit 25 according to one aspect of the disclosure with respect to a heat exchanger assembly.

[0049] The drive train 1 has the heat generator 2, comprising the at least one electric drive machine 3. In order to be able to remove the heat from a cooling circuit led through the heat generator 2, the drive train 1 has the heat removal circuit 25. The heat removal circuit 25 has at least a first heat exchanger 26 and a second heat exchanger 27 for removing heat from the cooling circuit. The cooling circuit can be formed, for example, by the first cooling circuit 4 and the second cooling circuit 21 shown in FIGS. 1 and 2. However, the cooling circuit can also be formed in a different manner. An exemplary design of a cooling system having a cooling circuit and a heat removal circuit is explained with reference to FIG. 7.

[0050] According to the disclosure, the heat removal circuit 25 is designed such that, in operation, a fluid used in the heat removal circuit 25, such as water, flows through the first heat exchanger 26 and, in parallel, through the second heat exchanger 27. This means that a volume flow 28 of the heat removal circuit 25 is at least partially parallelized, i.e., divided into at least two partial volume flows. The volume flow 28 is divided at a node 29 into a first partial volume flow 30 and a second partial volume flow 31. At least one heat exchanger is arranged in each of the partial volume flows 30, 31 so that the heat exchangers are flowed through in parallel.

[0051] In the embodiments shown in FIGS. 3 to 5, the drive train 1 has two electric drive machines 3. In addition, the drive train 1 has the power electronics unit 6, the first clutch 7 and/or the second clutch 8 and the gearbox 9 for each drive machine 3.

[0052] In the embodiment shown in FIG. 3, the drive train 1 has two heat exchangers for cooling the components for each drive machine 3. One heat exchanger for cooling the power electronics units 6 and one heat exchanger for cooling the drive machine 3, the first clutch 7, the second clutch 8 and/or the gearbox 9 are provided for each drive machine 3. In the first partial volume flow 30, the first heat exchanger 26 is arranged for cooling the (first) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9). In the second partial volume flow 31, the second heat exchanger 27 is arranged for cooling the (second) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9). A third heat exchanger 32 is arranged in the first partial volume flow 30 for cooling the (first) power electronics unit 6. A fourth heat exchanger 33 is arranged in the second partial volume flow 31 for cooling the (second) power electronics unit 6. The first partial volume flow 30 and the second partial volume flow 31 combine at a second node 34 to form the common volume flow 28. A first hydraulic resistance 35 is arranged in the first partial volume flow 30. The first hydraulic resistance 35 is designed as a passive adjusting element 36. A second hydraulic resistance 37 is arranged in the second partial volume flow 31. The second hydraulic resistance 37 is designed as a passive adjusting element 38. By means of the passive adjusting elements 36, 38, the division of the volume flow 28 into the partial volume flows 30, 31 can be adjusted initially.

[0053] In the embodiment shown in FIG. 4, the drive train 1 has a heat exchanger for cooling the (first and second) power electronics units 6 and a heat exchanger each for cooling each of the two drive machines 3. In the first partial volume flow 30, the first heat exchanger 26 is arranged for cooling the (first) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9). In the second partial volume flow 31, the second heat exchanger 27 is arranged for cooling the (second) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9). Arranged in the volume flow 28 is the third heat exchanger 32 for cooling the (first and second) power electronics units 6. The first partial volume flow 30 and the second partial volume flow 31 combine at the second node 34 to form the common volume flow 28. A hydraulic resistance 39 is arranged at the node 29. The hydraulic resistance 39 is designed as an active adjusting element 40. By means of the active adjusting element 40, the division of the volume flow 28 into the partial volume flows 30, 31 can be continuously controlled.

[0054] In the embodiment shown in FIG. 5, the drive train 1 has a heat exchanger for cooling the (first and second) power electronics units 6 and a heat exchanger each for cooling each of the two drive machines 3. The first heat exchanger 26 is arranged in the first partial volume flow 30 for cooling the (first) drive machine 3. The second heat exchanger 27 is arranged in the second partial volume flow 31 for cooling the (second) drive machine 3. Arranged in the volume flow 28 is the third heat exchanger 32 for cooling the (first and second) power electronics units 6. The first hydraulic resistance 35 designed as the passive adjusting element 36 is arranged in the first partial volume flow 30. The second hydraulic resistance 37 designed as the passive adjusting element 38 is arranged in the second partial volume flow 31. By means of the passive adjusting elements 36, 38, the division of the volume flow 28 into the partial volume flows 30, 31 can be adjusted initially.

[0055] The embodiment shown in FIG. 6 shows a heat removal circuit 41 in which a heat exchanger 42 for the (first and second) power electronics 6, a heat exchanger 43 for cooling the (first) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9) and a heat exchanger 44 for cooling the (second) drive machine 3 (having the first clutch 7, the second clutch 8 and/or the gearbox 9) are arranged sequentially one behind the other.

[0056] FIG. 7 shows an example of a basic structure of a cooling system 45. The cooling system 45 has a heat removal circuit/water cooling circuit 46 and multiple cooling circuits/cooling oil circuits 47. The structure of the heat removal circuit 46 corresponds to that of the heat removal circuit 41 shown in FIG. 6, in which a first heat exchanger 48, a second heat exchanger 49 and a third heat exchanger 50 are arranged in series one behind the other. A cooling pump 51 pumps the fluid, in this case water, through the heat removal circuit 46.

[0057] The first heat exchanger 48 exchanges heat with a first cooling circuit 52. In the first cooling circuit 52, fluid, in this case oil, is conveyed by a cooling pump 53 to the first power electronics 6 and to the second power electronics 6. The second heat exchanger 49 exchanges heat with a second cooling circuit 54. In the second cooling circuit 54, fluid, in this case oil, is conveyed by a cooling pump 55 to the first drive machine 3, the first clutch 7 and the second clutch 8 of a double clutch and the gearbox 9. The third heat exchanger 50 exchanges heat with a third cooling circuit 56. In the third cooling circuit 56, fluid, in this case oil, is conveyed by a cooling pump 57 to the second drive machine 3, the first clutch 7 and the second clutch 8 of a double clutch and the gearbox 9.

LIST OF REFERENCE SYMBOLS

[0058] 1 Drive train [0059] 2 Heat generator [0060] 3 Drive machine [0061] 4 Cooling circuit [0062] 5 Heat exchanger [0063] 6 Power electronics [0064] 7 First clutch [0065] 8 Second clutch [0066] 9 Gearbox [0067] 10 Volume flow [0068] 11 Oil sump [0069] 12 Suction filter [0070] 13 Cooling oil pump [0071] 14 First partial volume flow [0072] 15 First node [0073] 16 Second node [0074] 17 Second partial volume flow [0075] 18 Third partial volume flow [0076] 19 Hydraulic resistance [0077] 20 Passive adjusting element [0078] 21 Second cooling circuit [0079] 22 Heat exchanger [0080] 23 Suction filter [0081] 24 Cooling oil pump [0082] 25 Heat removal circuit [0083] 26 First heat exchanger [0084] 27 Second heat exchanger [0085] 28 Volume flow [0086] 29 Node [0087] 30 First partial volume flow [0088] 31 Second partial volume flow [0089] 32 Third heat exchanger [0090] 33 Fourth heat exchanger [0091] 34 Second node [0092] 35 Hydraulic resistance [0093] 36 Passive adjusting element [0094] 37 Hydraulic resistance [0095] 38 Passive adjusting element [0096] 39 Hydraulic resistance [0097] 40 Active adjusting element [0098] 41 Heat removal circuit [0099] 42 First heat exchanger [0100] 43 Second heat exchanger [0101] 44 Third heat exchanger [0102] 45 Cooling system [0103] 46 Heat removal circuit [0104] 47 Cooling circuit [0105] 48 First heat exchanger [0106] 49 Second heat exchanger [0107] 50 Third heat exchanger [0108] 51 Cooling pump [0109] 52 First cooling circuit [0110] 53 Cooling pump [0111] 54 Second cooling circuit [0112] 55 Cooling pump [0113] 56 Third cooling circuit [0114] 57 Cooling pump