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

Abstract

The invention relates to a thermal management system in an electrically powered vehicle, with at least one wet multi-disc brake and / or clutch (5, 7) by means of which brake actuation, for example for vehicle braking, can be carried out, wherein the multi-disc brake and / or clutch (5, 7) is connected in a brake circuit (B) in which coolant can be circulated to dissipate the waste heat generated during the braking process. According to the invention, for the purpose of dissipating the waste heat, the brake cooling circuit (B) is thermally coupled via an air / liquid heat exchanger (30) to an air duct (31) through which an exhaust air flow (I) can flow.

Description

[0001] The invention relates to a thermal management system according to the preamble of claim 1 and a method for operating such a thermal management system according to the preamble of claim 10.

[0002] An electrically powered vehicle can have at least one axle where the wheels are not braked by conventional dry disc or dry brakes, but by at least one wet multi-disc brake. Therefore, if the vehicle's electric motor is unable to recuperate energy, or can only do so partially, the multi-disc brake can take over the braking function, at least partially or completely. For example, the multi-disc brake can initiate braking depending on the current recuperation capacity.

[0003] In a vehicle of this type, the wet multi-disc brake is integrated together with the electric motor and the axle drive in a cooling / lubricating circuit, in which the multi-disc brake is lubricated with oil during vehicle braking in order to dissipate the waste heat generated during the braking process.

[0004] The problem with this type of vehicle is that the combination of the multi-disc brake and the connection to the cooling circuit of a battery-powered vehicle not only leads to an increase in consumption, but also to a reduction in range.

[0005] From DE 10 2009 026 985 A1: An arrangement for cooling and / or lubricating at least one multi-plate pack of a multi-plate clutch or a multi-plate brake of a vehicle is known. The arrangement includes a pump for supplying a coolant and / or lubricant flow, the volume flow of which can be varied at least as a function of the actuation of the multi-plate clutch or the multi-plate brake. The volume flow can be electronically controlled as required via a control device.

[0006] From WO 2020 / 245021 A1, a multi-disc brake for a motor vehicle is known, comprising two multi-disc devices and an actuating device for applying and / or releasing the multi-disc devices, as well as an electric drive for the translational actuation (spreading) of the actuating device, in particular the ramp unit. During spreading, the multi-disc devices are pre-tensioned in a metered manner by the actuating device, generating the desired frictional engagement. A correspondingly reversed control of the actuating device enables a correspondingly metered release of the brake.

[0007] The object of the invention is to provide a thermal management system and a method for operating such a thermal management system in which, compared to the prior art, an increase in fuel consumption is reduced when connecting the multi-disc brake / clutch to a brake cooling circuit of the battery-powered vehicle.

[0008] The problem is solved by the features of claim 1 or claim 10. Preferred embodiments of the invention are disclosed in the dependent claims.

[0009] The invention relates to a thermal management system in a vehicle with at least one wet multi-disc brake or clutch. The multi-disc brake or clutch is connected in a brake cooling circuit in which a coolant can circulate. According to the characterizing part of claim 1, the following measures are taken to efficiently dissipate the waste heat generated during braking: The brake cooling circuit is thermally coupled via an air / liquid heat exchanger to an air duct through which an exhaust air stream can flow.

[0010] The invention is based on the following insight: Generator-based (primary) recuperation in an electrified vehicle enables an average energy recovery of 60% to 70%; however, during emergency braking or in the event of an unstable driving condition, the vehicle is still decelerated almost exclusively via the friction brakes. A key aspect of the invention relates to an (additional) secondary recuperation of the remaining kinetic energy that cannot be regenerated via generators, through the intelligent and, if necessary, complete utilization of the waste heat generated by the braking system.A key aspect of the invention is a thermal management system that uses internal, wet-running multi-disc brakes on the front axle in combination with intelligent control of the heat flow from the multi-disc brake / clutch via two heat exchangers (a liquid / liquid heat exchanger and an air / liquid heat exchanger) to further utilize the energy that is usually separated as waste heat.

[0011] A valve assembly allows the battery cooling circuit to be connected or disconnected from the heat exchanger. The liquid-to-liquid heat exchanger enables heat transfer between the brake cooling circuit and the battery cooling circuit. A separate exhaust valve allows the airflow to the air-to-liquid heat exchanger to be diverted, thus improving the vehicle's aerodynamics. When the exhaust valve is open, energy is dissipated from the brake cooling circuit via the air-to-liquid heat exchanger. A control valve regulates the flow of this waste heat, directing it either to the surrounding environment or to the air conditioning system.

[0012] If the temperature in the battery cooling circuit is higher than in the brake cooling circuit, heat is transferred to the brake cooling circuit via the liquid-to-liquid heat exchanger. If the temperature there is too high, heat is dissipated via the exhaust valve. If the temperature in the brake cooling circuit is higher than in the battery cooling circuit, the waste heat from the brakes is used to condition the battery. Whenever heat is dissipated via the air-to-liquid heat exchanger, it is used for climate control of the vehicle interior, if needed.

[0013] A key aspect of the invention concerns the intelligent control of the thermal management system. Using the three valves described above, the intelligent control system optimally regulates the heat flow within the system. It is intelligent because it does not adjust the valves according to fixed operating points (T1>T2,...), but rather directs the heat to where it will make the greatest contribution to overall energy efficiency at the current operating point. Due to the system's inherent dead time, this also includes anticipating the customer's actions in the near future.

[0014] The advantages of the invention are summarized below: First, it optimizes the efficiency of using braking energy for engine / battery conditioning or interior temperature control. Furthermore, systemic losses are avoided because energy does not need to be converted for further use but is utilized directly as heat. The use of the multi-disc brake or clutch also completely eliminates particle emissions. The wet brakes are significantly lighter than comparable dry friction brakes. Moreover, the multi-disc brakes are designed for lifetime operation, meaning that no brake components need to be replaced during customer use.

[0015] In one technical implementation, the multi-disc brake / clutch is no longer mounted externally near the wheel, but internally near the drive motor. This makes controlling heat flow easier than at the moving wheel, while reducing the insulation requirements. Furthermore, the shorter paths result in lower oil consumption and reduced weight.

[0016] The braking system according to the invention is preferably used on the front axle. Due to physical reasons, the braking energy is higher there than on the rear axle, which allows for greater energy recovery. Furthermore, integration into existing systems in the front of the vehicle is possible (cooling circuit, air supply, interior).

[0017] To reduce the system's inherent dead time, the intelligent control system can also anticipate which actions the customer will perform in the near future. This anticipation ("prediction") is made possible by pattern recognition, i.e., based on artificial intelligence. Due to the sometimes highly individualized requirements, this does not necessarily involve a factory-pre-trained neural network. This network is initially used (at vehicle purchase) but is further trained based on the history of cooling / heating requirements of all circuits, as well as the prevailing temperatures, location- and road-dependent speed profiles, and the driver's identity in the vehicle. The selection of the neural network to be used is based on a periodic analysis of the predictive capabilities of both networks.

[0018] The following example illustrates how the electronic control unit works: While driving, the customer can be navigated to a fast-charging station. The control unit determines that the battery temperature needs to be increased for optimal charging performance. Therefore, it directs all available heat into the battery.

[0019] In another example, the customer is just leaving the highway and driving the next 20 km on a winding country road. The brakes are cold because they weren't used during highway driving. Anticipating frequent braking and heat in the braking system, no heat is transferred to the braking system even while on the highway.

[0020] The thermal management system according to the invention is further characterized by short pipe lengths and the highest possible functional integration. This prevents costs, installation space, weight, and uncontrolled heat losses from the system. A key focus is also on optimized airflow through the air / liquid heat exchanger to minimize the impact on the vehicle's drag coefficient (Cd).

[0021] The following are key aspects of the invention highlighted in detail: To control the exhaust air flow, the air duct downstream of the air / liquid heat exchanger can have a control valve. In a first switch position, the control valve directs the exhaust air flow out of the vehicle. In a second switch position, the control valve directs the exhaust air flow to a vehicle air conditioning unit, where the exhaust air flow is conditioned and then directed further into the vehicle interior.

[0022] In a structurally simple implementation of the waste heat generated during braking, the exhaust airflow is automatically created by the vehicle's airflow and introduced into the air duct from outside the vehicle. The air duct can have a shut-off valve upstream of the air-to-liquid heat exchanger, which interrupts the exhaust airflow to, for example, improve the vehicle's aerodynamics. To further utilize the waste heat generated during braking, the brake cooling circuit can be thermally coupled to a battery cooling circuit via a liquid-to-liquid heat exchanger, in which coolant can be circulated. The battery cooling circuit can have a valve arrangement that interrupts the thermal coupling between the liquid-to-liquid heat exchanger and the battery or electric motor.

[0023] In the battery cooling circuit, the coolant is circulated by a circulation pump. The battery or electric motor can be fluidically connected to the liquid-to-liquid heat exchanger via an inlet line and a drain line. A bypass line, connected in parallel to the battery or electric motor, can run between the inlet and drain lines. In the first switching position of the valve assembly, coolant circulation occurs via the battery or electric motor while the bypass line is closed. In the second switching position of the valve assembly, coolant circulation can occur via the bypass line while the coolant flow through the battery or electric motor is closed.

[0024] The control components of the thermal management system—that is, the exhaust air flow control valve, the exhaust air flow shut-off valve, the coolant valve assembly, and the circulation pumps—can be controlled by an electronic control unit depending on the heating or cooling requirements in the multi-plate clutch or brake, the battery / electric motor, and / or the air conditioning unit. Temperature sensors can be assigned to the electronic control unit to measure the actual temperature in the brake cooling circuit and the battery cooling circuit. The control unit can then easily control the components based on these measured temperatures.

[0025] In a preferred technical implementation, the control unit can enable anticipation through pattern recognition based on artificial intelligence, thereby generating control commands early to reduce inherent dead times in the thermal management system. Preferably, the control unit can generate the control commands based on a factory-pre-trained neural network.

[0026] An embodiment of the invention is described below with reference to the accompanying figures.

[0027] They show: Fig. 1 and Fig. 2 different representations, each illustrating the thermal management system according to the invention.

[0028] In the Fig. Figure 1 shows an electrified vehicle axle, such as the front axle of a two-track vehicle, which includes an electric motor EM and an axle drive 3. A high-voltage battery 4 is assigned to the electric motor EM for energy supply. Conventional vehicle wheel brakes (i.e., dry-running disc or drum brakes) are omitted from the vehicle axle. Instead of such conventional vehicle wheel brakes, the vehicle axle has a central multi-disc brake 5 and multi-disc clutches 7. The central multi-disc brake 5 effects vehicle braking either alternatively or in addition to the multi-disc clutches 7.

[0029] The electric machine EM is connected via its rotor shaft 9 to the gearbox structure of the axle drive 3, from whose output shafts 17 lead to the vehicle wheels. The gearbox structure has in the Fig. 1 the central multi-plate brake 5 and one of the multi-plate clutches 7 on each side of the vehicle. The multi-plate brake 5 acts between a gearbox housing and a differential housing of an axle differential, while the two multi-plate clutches 7 are each components of a superimposed transmission 19, with the aid of which torque vectoring can be carried out during driving.

[0030] In the Fig. Figure 1 also indicates a brake cooling circuit B, in which, among other things, the multi-plate clutches 7 and the multi-plate brake 5 are connected. These are cooled by oil that collects in a sump 20 and is then conveyed via a suction line 22 to the suction side of a circulation pump 24 of the brake cooling circuit B. From the pressure side of the circulation pump 24, a pressure line 26 leads to the multi-plate brake 5 and to the multi-plate clutches 7.

[0031] As from the Fig. 1 or Fig. As further shown in Figure 2, an air / liquid heat exchanger 30 is connected in the pressure line 26 of the brake cooling circuit B, which thermally couples the brake cooling circuit B to an air duct 31. This air duct is permeable to an exhaust air flow I. Downstream of the air / liquid heat exchanger 30, the air duct 31 has a control valve 35. In its first switching position, the control valve 35 discharges the exhaust air flow I from the vehicle into the environment. In its second switching position, the control valve 35 directs the exhaust air flow I to a vehicle air conditioning unit 37, where the exhaust air flow I is conditioned and then directed into the vehicle interior.

[0032] The exhaust airflow I is generated by the airflow during driving and is directed from outside the vehicle into the air duct 31. As shown in the Fig. 1 or Fig. As further shown in Figure 2, the air duct 31 upstream of the air / liquid heat exchanger 30 has a shut-off valve 39 by means of which the exhaust air flow I can be interrupted in order to improve the aerodynamics of the vehicle.

[0033] According to the Fig. 1 or Fig. 2 The thermal management system also consists of a battery cooling circuit E, which can be thermally coupled to the brake cooling circuit B via a liquid-to-liquid heat exchanger 41. The battery cooling circuit E has a valve arrangement 43 by means of which the thermal coupling between the liquid-to-liquid heat exchanger 41 and the battery 4 or the electric machine EM can be interrupted.

[0034] In the battery cooling circuit E, the coolant is circulated by means of a circulation pump 45 (only in the Fig. (1 shown) from the liquid-to-liquid heat exchanger 41 via an inlet line 47 to the battery / electric motor and via an outlet line 49 back to the liquid-to-liquid heat exchanger 41. The inlet and outlet lines 47 and 49 are connected via a bypass line 51 connected in parallel to the battery / electric motor.

[0035] In the first switching position of the valve assembly 43, the coolant is circulated via the battery / electric motor, while the bypass line 51 is deactivated. In contrast, in the second switching position of the valve assembly 43, the coolant is circulated via the bypass line 51, while the coolant path through the battery / electric motor is deactivated.

[0036] The control components of the thermal management system, i.e., the exhaust air flow control valve 35, the exhaust air flow shut-off valve 39, as well as the coolant valve assembly 43 and the circulation pumps 24, 54, are controlled in the multi-plate clutch or brake 5, 7, the battery / electric motor and / or the air conditioning unit 37 by means of an electronic control unit 53, depending on the heating or cooling requirement. Fig. 2) controlled. Temperature sensors 55 and 57 are assigned to the electronic control unit 53, which detect an actual temperature T2 in the brake cooling circuit B and an actual temperature T1 in the battery cooling circuit E. The control unit 53 simply controls the control components based on the detected actual temperatures T1 and T2.

[0037] A key aspect of the invention relates to the fact that the control unit 53, through pattern recognition based on artificial intelligence, enables anticipation in order to generate control commands early on, thereby reducing inherent dead times in the thermal management system. Therefore, the control unit 53 can generate the control commands based on a factory-pre-trained neural network. During vehicle use, the control unit 53 is further trained based on the history of cooling / heating requirements of all circuits, as well as the prevailing temperatures, location- and road-dependent speed profiles, and the driver's identity in the vehicle. REFERENCE MARK LIST: 3 gearboxes 4 Traction battery or high-voltage battery 5-disc brake 7-plate clutch 9 Rotor shaft 17 output shafts 19 superimposed gear units 20 swamp 22 Suction line 24 Circulation pump 26 Pressure line 30 air / liquid heat exchangers 31 Air duct 35 Control valve 37 Air conditioner 39 shut-off valve 41 Liquid / liquid heat exchangers 43 Valve arrangement 45 Circulation pump 47 Inlet pipe 49 Drain line 51 Bypass line 53 electronic control unit 54 Circulation pump 55, 57 temperature sensors I Exhaust air flow B Brake cooling circuit E Battery cooling circuit QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2009 026 985 A1

[0005] WO 2020 / 245021 A1

[0006]

Claims

[1] Thermal management system in an electrically powered vehicle, with at least one wet multi-disc brake and / or clutch (5, 7) by means of which brake actuation, for example for vehicle braking, can be carried out, wherein the multi-disc brake and / or clutch (5, 7) is connected in a brake circuit (B) in which coolant can be circulated to dissipate the waste heat generated during the braking process, characterized by , that to dissipate the waste heat the brake cooling circuit (B) is thermally coupled via an air / liquid heat exchanger (30) to an air duct (31) which can be permeated by an exhaust air flow (I). [2] Thermal management system according to claim 1, characterized by, that the air duct (31) downstream of the air / liquid heat exchanger (30) has a control valve (35) which in a first switching position directs the exhaust air flow (I) out of the vehicle, and in a second switching position directs the exhaust air flow (I) to a vehicle air conditioning unit (37), through which the exhaust air flow (I) can be directed further into the vehicle interior. [3] Thermal management system according to claim 1 or 2, characterized by , that the exhaust air flow (I) can be generated by the airflow during driving operation and can be directed from outside the vehicle into the air duct (31), and that in particular the air duct (31) upstream of the air / liquid heat exchanger (30) has a shut-off valve (39) by means of which the exhaust air flow (I) can be interrupted in order to improve in particular the aerodynamics of the vehicle. [4] Thermal management system according to any one of the preceding claims, characterized by, that in order to utilize the waste heat the brake cooling circuit (B) can be thermally coupled to a battery cooling circuit (E) via a liquid / liquid heat exchanger (41) in which coolant can be circulated, and that in particular the battery cooling circuit (E) has a valve arrangement (43) by means of which the thermal coupling between the liquid / liquid heat exchanger (41) and the battery / electric machine can be interrupted. [5] Thermal management system according to claim 4, characterized by, that the coolant can be circulated from the liquid / liquid heat exchanger (41) via a supply line (47) to the battery / electric machine and via a drain line (49) back to the liquid / liquid heat exchanger (41) by means of a circulation pump (54), and that the supply and drain lines (47, 49) are connected via a bypass line (51) connected in parallel to the battery / electric machine, and that in particular in a first switching position of the valve arrangement (43) the coolant circulation takes place via the battery / electric machine while the bypass line (51) is deactivated, and / or that in a second switching position of the valve arrangement (43) the coolant circulation takes place via the bypass line (51) while the coolant path through the battery / electric machine is deactivated. [6] Thermal management system according to any of the preceding claims, characterized by, that the control components of the thermal management system, namely the exhaust air flow control valve (35), the exhaust air flow shut-off valve (39) and the coolant valve assembly (43), can be controlled in the multi-plate brake / clutch (5, 7), in the battery / electric machine and / or in the air conditioning unit (37) by means of an electronic control unit (53), depending on the heating or cooling requirements. [7] Thermal management system according to any one of the preceding claims, characterized by , that the control unit (53) is assigned temperature sensors (55, 57) which detect an actual temperature (T1, T2) in the brake cooling circuit (B) and in the battery cooling circuit (E), and that the control unit (53) controls the control components depending on the detected actual temperatures (T1, T2). [8] Thermal management system according to claim 7, characterized by, that the control unit (53) performs an anticipation by means of pattern recognition based on artificial intelligence, which makes it possible to generate control / regulation commands early in order to reduce system-inherent dead times in the thermal management system. [9] Thermal management system according to claim 8, characterized by , that the control unit (53) generates the control commands on the basis of a factory pre-trained neural network, and that the neural network is additionally trained during the vehicle's service life on the basis of the history of cooling / heating power requirements of all circuits, as well as the prevailing temperatures, the location- and road-dependent speed profiles and the driver identity in the vehicle. [10] Method for operating a thermal management system in an electrically powered vehicle according to any of the preceding claims.

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