Thermal management system and method for operating such a thermal management system

Abstract

The invention relates to a thermal management system in an electrically operated vehicle with a vehicle axle that has at least one wet-running multi-disc brake and / or clutch (5, 7) which acts on the vehicle axle and which can be actuated by a control unit (48) in order to actuate a braking process, for example a vehicle braking process, wherein the multi-disc brake and / or clutch (5, 7) is connected into a coolant / lubricant circuit (K) in which coolant / lubricant can be circulated in order to cool the multi-disc brake and / or clutch (5, 7). According to the invention, when there is a heating requirement (SB, SI, SP) for a vehicle-side load, for example a traction battery (4), a pulse-controlled inverter (PWR) and / or a vehicle interior (I), the control unit (48) actuates the multi-disc brake and / or clutch (5, 7) such that the waste heat generated in the process at least partially covers the heating requirement (SB, SI, SP).

Description

[0001] Thermal management system and method for operating such a thermal management system

[0002] DESCRIPTION:

[0003] The invention relates to a thermal management system according to the preamble of claim 1 and to a method for operating such a thermal management system according to the preamble of claim 10.

[0004] An electrically powered vehicle can have at least one axle where the vehicle wheels are braked not with conventional, dry disc or dry brakes, but with at least one wet multi-disk brake. Therefore, if the vehicle's electric motor is not capable of recuperation or is only partially capable of recuperation, the multi-disk brake can take over the braking task at least partially or completely. For example, the multi-disk brake can cause vehicle braking depending on the current recuperation capacity.

[0005] In a vehicle of this type, the wet-running multi-disk brake is integrated together with the electric motor and the axle drive in a coolant / lubricant circuit in which oil flows through the multi-disk brake for cooling purposes during the vehicle braking.

[0006] The problem with this type of vehicle is that, due to the high efficiency of the electric motor, there is a lack of heat sources for regulating the temperature of the vehicle interior, for example, a pulse-controlled inverter, and / or a traction battery. This deficiency is compensated for in the current state of the art by appropriately dimensioned electric auxiliary heaters. However, this comes at the expense of the vehicle's efficiency and range.

[0007] DE 10 2009 026 985 A1 discloses an arrangement for cooling and / or lubricating at least one disk pack of a multi-disk clutch or multi-disk brake of a vehicle. The arrangement comprises a pump for providing a coolant and / or lubricant flow, the volumetric flow of which can be varied at least as a function of the actuation of the multi-disk clutch or multi-disk brake. The volumetric flow can be electronically controlled as needed via a control device.

[0008] WO 2020 / 245021 A1 discloses a multi-disk brake for a motor vehicle. It comprises two multi-disk devices and an actuating device for applying and / or releasing the brakes, as well as an electric drive for translational actuation (spreading) of the actuating device, such as, in particular, the ramp unit. During a spreading action, the multi-disk devices are preloaded in a controlled manner by the actuating device, creating a desired frictional engagement. A correspondingly reversed control of the actuating device enables a correspondingly controlled brake release.

[0009] The object of the invention is to provide a thermal management system and a method for operating such a thermal management system in which the heating requirement of a vehicle consumer can be met more efficiently than in the prior art.

[0010] The object is solved by the features of claim 1 or claim W. Preferred developments of the invention are disclosed in the subclaims.

[0011] The invention relates to a thermal management system in an electrically powered vehicle. Its vehicle axle can have at least one wet-running multi-disk brake or multi-disk clutch acting on the vehicle axle. Brake actuation, for example for vehicle braking, can be performed with the aid of the multi-disk brake or multi-disk clutch. The multi-disk brake or multi-disk clutch are connected in a coolant / lubricant circuit in which coolant / lubricant can be circulated to cool the multi-disk brake / clutch during braking actuation. Furthermore, the vehicle has a heating circuit through which coolant flows. When heating is required, at least one vehicle consumer, such as a traction battery, a pulse-controlled inverter, and / or the vehicle interior, can be heated with the aid of the heating circuit. A heat exchanger that can be thermally coupled to the heating circuit can be connected in the coolant / lubricant circuit.In this way, the waste heat generated when the multi-disk brake / clutch is applied can be used to heat the vehicle's consumer.

[0012] The multi-disk brake is operated with a corresponding actuator. The multi-disk brake actuator is preferably not hydraulically controlled, but rather electrically controlled with a brake signal.

[0013] When a brake application occurs, particularly during vehicle braking, the control unit can activate actuators in the coolant / lubricant circuit. Examples of actuators include a circulation pump and / or a control valve, which can be used to control the coolant / lubricant flow in the coolant / lubricant circuit to cool the multi-disk brake or to dissipate waste heat from the multi-disk brake.

[0014] When such a brake application occurs, the control unit can not only activate the coolant / lubricant circuit; it can also activate the heating circuit by appropriately controlling actuators to transfer the multi-disk brake waste heat from the coolant / lubricant circuit. Therefore, the consumer connected in the heating circuit can be supplied with the waste heat to meet its heating requirements. In the embodiment described above, the multi-disk brake serves a dual function, both for vehicle braking and as a heating element, to at least partially cover the heating requirements of a vehicle consumer.

[0015] Alternatively, in the embodiment described below, the multi-disk brake can be used exclusively as a heating element without simultaneously initiating vehicle braking. In this embodiment, an evaluation unit can be assigned to the control unit, which determines whether the consumer requires heating. If such a heating requirement exists, the control unit can start a heating mode. In heating mode, during ferry operation, both the multi-disk brake actuator is controlled with an electrical braking signal and an electric motor acting as a drive unit is controlled with an additional drive torque. In this case, the electric motor runs against the brake-actuated multi-disk brake to generate waste heat in the multi-disk brake, which is intended to at least partially cover the consumer's heating requirement.The brake signal and the additional drive torque are preferably coordinated in such a way that the vehicle occupants do not perceive any vehicle braking.

[0016] In the heating mode described above, the control unit additionally controls actuators, in particular a circulation pump and / or a control valve, in the heating circuit to activate it. This allows the waste heat generated by the multi-disk brake to be transferred to the consumer with high efficiency.

[0017] An embodiment of the invention is described below with reference to the attached figures.

[0018] They show:

[0019] Fig. 1 to 3 each show different representations which illustrate the thermal management system according to the invention. Figure 1 shows an electrified vehicle axle, for example the rear axle of a two-track vehicle, which has an electric machine EM and a transmission 3. The electric machine EM is connected to a high-voltage battery 4 (Figure 3). Conventional vehicle wheel brakes (i.e. dry-running disc or drum brakes) have been omitted from the vehicle axle. Instead of such conventional vehicle wheel brakes, the vehicle axle has a central multi-disk brake 5 (described later) and multi-disk clutches 7. The central multi-disk brake 5 effects vehicle braking alternatively or in addition to the multi-disk clutches 7.

[0020] The electric motor EM is connected via its rotor shaft 9, with a transmission stage 11 interposed, to the input side of an axle differential 15. Its output sides are in driving connection with the vehicle wheels. In Figure 1, the electric motor EM is installed transversely in the vehicle axle. Accordingly, the rotor shaft 9 and the output shafts 17, 18 are axially parallel to one another, leading from the output sides of the axle differential 15 to the vehicle wheels. Likewise, the multi-disk clutches 7 and the multi-disk brake 5 installed in the vehicle axle are axially parallel to one another in the vehicle's transverse direction y.

[0021] The vehicle axle, viewed in the vehicle's transverse direction y, has a superposition gear 19 on each side of the vehicle, with which the electric motor EM can be directly connected to one of the output shafts 17, 18, bypassing the axle differential 15. With the help of the two superposition gears 19, the electric motor EM can therefore drive directly to the vehicle wheels via load paths, bypassing the axle differential 15, in order to perform torque vectoring.

[0022] The intermediate gear stage 11 is in driving connection with an input-side axle differential gear 21. The axle differential gear 21 is connected in a rotationally fixed manner to a rotating differential housing 25. According to Figure 1, the axle differential 15 drives in the vehicle transverse direction y in a 50 / 50 distribution on both sides to the two wheels leading to the vehicle.

[0023] Output shafts 17, 18 off.

[0024] The two superposition gears 19 are mirror-inverted with respect to a vehicle center longitudinal plane passing through the axle differential 15. Thus, each of the two superposition gears 19 has a gear ratio stage 28 designed in the manner of a planetary gear (but without an external ring gear) having a sun gear 47 on the outside of the vehicle, viewed in the vehicle transverse direction y, which is non-rotatably mounted on the output shaft 17, 18, and a sun gear 29 on the inside of the vehicle, which is rotatably arranged as an idler gear on the output shaft 17, 18. The sun gear 29 on the inside of the vehicle meshes with planet gears 41 on the inside of the vehicle, each of which is non-rotatably mounted on a carrier shaft 43. Each of the carrier shafts 43 has a planet gear 45 on the outside of the vehicle, which meshes with the sun gear 47 on the outside of the vehicle.

[0025] The vehicle's internal sun gear 29 (i.e., the idler gear) sits together with an inner disk carrier 31 of the multi-plate clutch 7 on a hollow shaft through which the output shaft 17, 18 passes. The inner disk carrier 31 of the multi-plate clutch 7 interacts via a disk pack with an outer disk carrier 39, which is non-rotatably connected to the differential housing 25. The disk pack located between the outer disk carrier 39 and the inner disk carrier 31 can be pressurized via a multi-plate clutch actuator 49 to actuate the multi-plate clutch 7 to a predetermined degree of engagement. The multi-plate clutch 7 is powershiftable and controllable with slip.

[0026] The multi-disk brake 5 consists of an inner disc carrier 59 and an outer disc carrier 61 with a disc pack arranged between them. The inner disc carrier 59 is arranged in a rotationally fixed manner on the differential housing 25, while the outer disc carrier 61 is connected in a rotationally fixed manner to the transmission housing wall 55. The disc pack located between the outer disc carrier 61 and the inner disc carrier 59 can be pressurized via an annular piston (not shown). This piston is rotated by an electromechanical multi-disk brake actuator 51 around a horizontal

[0027] Stroke adjustable to operate the multi-disk brake 5.

[0028] Figure 2 shows a coolant / lubricant supply system in which the multi-plate clutches 7, the superposition gears 19, the multi-plate brake 5, and the electric motor EM are connected in a coolant / lubricant circuit K. The above-mentioned components 5, 7, 19, EM of the vehicle axle are traversed by oil for cooling / lubrication. This oil collects in a sump 20 and from there is fed via a suction line 22 to the suction side of a circulation pump 24 of the coolant / lubricant circuit K. A pressure line 26 leads from the pressure side of the circulation pump 24 to the components 5, 7, 19, EM of the vehicle axle.

[0029] As further shown in Figure 2, a heat exchanger 30 is connected in the pressure line 26 of the coolant / lubricant circuit K, which heat exchanger can be thermally coupled to a heating circuit H. Coolant, in particular water, can flow through the heating circuit H. In Figure 2, the electric motor EM and a pulse-controlled inverter PWR are connected in the heating circuit H, for example. Alternatively and / or additionally, according to the circuit diagram in Figure 3, a refrigerant circuit 32 of a vehicle air conditioning system 34, the traction battery 4, and the pulse-controlled inverter PWR can be connected in parallel in the heating circuit H.

[0030] In Figure 3, the heating circuit H has a main line 35, which, together with the heat exchanger 30, forms a closed circuit. Three sub-lines 36, 37, 38 branch off from the main line 35 in parallel. A shut-off valve 40 is arranged in each of these sub-lines 36, 37, 38. The first sub-line 36 is thermally coupled by means of a heat exchanger 42 to the refrigerant circuit 32 of the vehicle air conditioning system 34, which is used to control the temperature of a vehicle interior I. The second sub-line 37 is coupled by means of a heat exchanger 44 to a cooling circuit of the traction battery 4, while the third sub-line 38 is thermally coupled by means of a heat exchanger 46 to the cooling circuit of the pulse-controlled inverter PWR. The thermal management system also has a control unit 48 (Figure 3) with which all actuators 24, 40, 54 of the coolant / lubricant circuit K and the heating circuit H can be controlled.An evaluation unit 50 is assigned to the control unit 48 and is in signal communication with temperature sensors 52. These sensors are used to determine the current temperatures 3i, 3B, 3P in the vehicle interior I, in the traction battery 4, and in the pulse-controlled inverter PWR. In the evaluation unit 50, the current temperatures 3i, 3B, 3P are compared with corresponding target values. From this comparison, the evaluation unit 50 determines whether there is a heating requirement for the vehicle air conditioning system 34, for the traction battery 4, and / or for the pulse-controlled inverter PWR. If such a heating requirement exists, the evaluation unit 50 transmits a corresponding heating requirement signal Si, SB, SP to the control unit 48.

[0031] Based on such a heating demand signal Si, SB, SP, the control unit 48 starts a heating mode. In heating mode, when the vehicle is in motion, the multi-disk brake actuator 51 (Figure 1) is controlled with a brake signal B and the electric motor EM with an additional drive torque M. In this way, the electric motor EM is driven against the actuated multi-disk brake 5 to generate waste heat. The brake signal B or the resulting braking force and the additional drive torque M are coordinated in such a way that the vehicle occupants do not perceive any vehicle braking.

[0032] At the same time, in heating mode, the control unit 48 also actuates the circulation pumps 24, 54 and the shut-off valves 40 in the heating circuit H and the coolant-lubricant circuit H, K. In this way, the waste heat generated by the multi-disk brake 5 is transferred to the respective consumer I, 4 and / or PWR in order to at least partially cover its heating requirements. LIST OF REFERENCE SYMBOLS:

[0033] 3 gearboxes

[0034] 4 Traction battery or high-voltage battery

[0035] 5-disk brake

[0036] 7 multi-plate clutch

[0037] 9 Rotor shaft

[0038] 11 countershaft

[0039] 15 axle differential

[0040] 17, 18 Output shafts

[0041] 19 superposition gears

[0042] 20 swamp

[0043] 21 axle differential gear

[0044] 22 Suction line

[0045] 24 Circulation pump

[0046] 25 differential housing

[0047] 26 pressure line

[0048] 28 gear ratios

[0049] 29 vehicle-internal sun gear

[0050] 30 heat exchangers

[0051] 31 Inner plate carrier of the multi-plate clutch

[0052] 32 Refrigerant circuit

[0053] 34 Vehicle air conditioning

[0054] 35 Main line

[0055] 36, 37, 38 sub-lines

[0056] 39 Outer plate carrier of the multi-plate clutch

[0057] 40 check valve

[0058] 41 vehicle-internal planetary gears

[0059] 42 heat exchangers

[0060] 43 Carrier wave

[0061] 44 heat exchangers

[0062] 45 vehicle-external planetary carriers

[0063] 46 heat exchangers

[0064] 47 vehicle-external sun gear 48 control unit

[0065] 49 Multi-plate clutch actuator

[0066] 50 evaluation unit

[0067] 51 Multi-disc brake actuator 52 Temperature sensor

[0068] 54 Circulation pump

[0069] 55 Gearbox housing wall

[0070] 59 Brake inner disc carrier

[0071] 61 Brake outer disc carrier 3i Interior temperature

[0072] 3B Battery temperature

[0073] 3P pulse inverter temperature

[0074] K Coolant / lubricant circuit

[0075] H Heating circuit M Additional drive torque

[0076] B Brake signal

[0077] Si, SB, SP heating demand signal

Claims

PATENT CLAIMS:

1. Thermal management system in an electrically powered vehicle, the vehicle axle of which has at least one wet-running multi-disk brake and / or clutch (5, 7) acting on the vehicle axle, which can be controlled by a control unit (48) in order to carry out a brake actuation, for example for vehicle braking, wherein the multi-disk brake and / or clutch (5, 7) is connected in a coolant / lubricant circuit (K) in which coolant / lubricant can be circulated to cool the multi-disk brake and / or clutch (5, 7), characterized in that when there is a heating requirement (SB, SI, SP) for a vehicle-side consumer, for example a traction battery (4), a pulse-controlled inverter (PWR) and / or a vehicle interior (I), the control unit (48) actuates the multi-disk brake and / or clutch (5, 7), and that the waste heat generated thereby covers the heating requirement (SB, SI, SP) is at least partially covered.

2. Thermal management system according to claim 1, characterized in that the control unit (48) is assigned an evaluation unit (50) which determines the presence of a heating requirement (SB, SI, SP) of the consumer (I, I, PWR), and in that when a heating requirement (SB, SI, SP) is present the control unit (48) starts a heating mode in which, in driving operation, both the multi-disk brake and / or clutch (5, 7) can be controlled with a braking signal or with a braking force (B) and an electric machine (EM) acting as a drive unit can be controlled with an additional driving torque (M), so that the electric machine (EM) runs against the multi-disk brake and / or clutch (5, 7) which is subjected to braking force in order to generate waste heat.

3. Thermal management system according to claim 2, characterized in that the brake signal or the brake force (B) and the additional drive torque (M) are coordinated in such a way that the vehicle occupants do not perceive any vehicle braking.

4. Thermal management system according to one of the preceding claims, characterized in that the coolant / lubricant circuit (K) has a heat exchanger (30) which can be thermally coupled to a heating circuit (H), and in that waste heat generated by the multi-disk brake and / or clutch (5, 7) is dissipated via the heat exchanger (30).

5. Thermal management system according to claim 4, characterized in that the consumer is connected to the heating circuit (H), and that the consumer can be heated by means of the heating circuit (H) when there is a heating requirement (SB, SI, SP).

6. Thermal management system according to one of the preceding claims, characterized in that the multi-disk brake and / or clutch (5, 7) can be actuated by means of an in particular electromechanical actuator (51), and in that in particular the actuator (51) can be controlled by a control unit (48) with a brake signal (B).

7. Thermal management system according to one of the preceding claims, characterized in that the control unit (48) activates the coolant / lubricant circuit (K) when a brake application occurs, in particular vehicle braking, in order to cool the multi-disk brake and / or clutch (5, 7) or to dissipate waste heat from the multi-disk brake and / or clutch (5, 7).

8. Thermal management system according to one of claims 4 to 7, characterized in that the control unit (48) activates not only the coolant / lubricant circuit (K) but also the heating circuit (H) when a brake is applied in order to transfer waste heat from the coolant / lubricant circuit (K) to the heating circuit (H) and in particular to supply the consumer (I, B, PWR) connected in the heating circuit (H) with the waste heat.

9. Thermal management system according to one of claims 4 to 8, characterized in that in the heating mode, the control unit (48) controls actuators, in particular a circulation pump (52, 54) and / or a control valve (40), in the heating circuit (H) and in the coolant-lubricant circuit (K) in such a way that the waste heat generated by the multi-disk brake (5) can be transferred to the consumer (I, B, PWR).

10. A method for operating a thermal management system in an electrically powered vehicle, in particular according to one of the preceding claims, wherein the vehicle axle of the vehicle has at least one wet-running multi-disk brake and / or clutch (5, 7) acting on the vehicle axle, which is controlled by a control unit (48) to perform a brake actuation, for example for vehicle braking, wherein the multi-disk brake and / or clutch (5, 7) is connected in a coolant / lubricant circuit (K) in which coolant / lubricant is circulated to cool the multi-disk brake and / or clutch (5, 7), characterized in that when there is a heating requirement (SB, SI, SP) for a vehicle-side consumer, for example a traction battery (4), a pulse-controlled inverter (PWR) and / or a vehicle interior (I), the control unit (48) actuates the multi-disk brake and / or clutch (5, 7), and that the waste heat generated thereby meets the heating requirements (SB, SI,SP) at least partially covers.

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