Cooling circuit and method for conveying a coolant in a motor vehicle as well as motor vehicle

Abstract

Cooling circuit (10) for conveying a coolant in a motor vehicle (11), comprising an upstream common cooling circuit section (14) and a downstream common cooling circuit section (15), which are connected to each other via at least two parallel-connected cooling circuit sections (16-1, 16-2) for distributing the coolant from the common cooling circuit sections (14, 15) to the parallel-connected cooling circuit sections (16-1, 16-2), wherein a turbine wheel (17-1, 17-2) is rotatably arranged in each of the parallel-connected cooling circuit sections (16-1, 16-2), which can be driven by the coolant flowing through the respective parallel-connected cooling circuit section (16-1, 16-2), wherein the turbine wheels (17-1, 17-2) are coupled to each other in a rotationally fixed manner; furthermore a motor vehicle (11) with such a cooling circuit (10) and a method for conveying a coolant in such a cooling circuit (10) of a motor vehicle (11).

Description

[0001] The invention relates to a cooling circuit for circulating a coolant in a motor vehicle. The invention further relates to a motor vehicle with such a cooling circuit and to a method for circulating a coolant in a cooling circuit of a motor vehicle.

[0002] In battery electric vehicles (BEVs) with all-wheel drive, where at least one electric drive motor is assigned to each drive axle, the electric drive motors and various electrical components in each drivetrain must be supplied with a coolant, such as water or a water-glycol mixture. The coolant supply is typically provided by a coolant pump, with a coolant flow being divided in parallel between both drivetrains. The ratio of the flow rates is determined by the pump capacity and the pressure losses of the components in the respective parallel cooling circuit sections.

[0003] To set a desired flow rate ratio in both drive trains or parallel cooling circuit sections, fixed orifice plates are typically used as throttles. This compensates for the different pressure losses of the components in the respective parallel cooling circuit sections and ensures the minimum flow rates in both drive trains or through both parallel cooling circuit sections.

[0004] When multiple component variants are used in the cooling circuit (e.g., different power classes of the electric drive motors), a separate throttle design must be developed and provided for each possible configuration. The more numerous the possible combinations of components in a cooling circuit, the more different throttle variants are required. While a reduction in the number of throttle variants can be compensated for by increasing the pump capacity, this comes at the expense of electrical consumption and increases the cost of a more powerful coolant pump. Furthermore, excessive pump capacity leads to a loss of efficiency.

[0005] Designing the cooling circuit for various component configurations under all possible operating conditions, such as different operating temperatures and flow rates (i.e., pump speeds), requires significant simulation and testing. Integrating components from second or third-party suppliers necessitates complex redesign, or components may be unusable due to differing pressure losses. The throttles must not be mixed up during assembly or at the supplier, requiring additional measures such as poka-yoke, pick-by-light, DMC, etc.

[0006] From DE 10 2006 054 223 A1, a cooling system for a motor vehicle with an internal combustion engine is known, in which, in particular, a thermostat and a pump-driven circulation of the coolant are described. The system has several coolant paths with branch lines, return lines, and valves, wherein a throttling device or a thermostat regulates the coolant flow between different circuits.

[0007] WO 2012 / 035202 A1 discloses a cooling system for an internal combustion engine with two cooling circuits: a low-temperature circuit (LT) and a high-temperature circuit (HT). The HT circuit includes a turbine-driven pump, the turbine of which is driven by the LT circuit.

[0008] DE 10 2013 017 624 A1 describes a cooling device with a high-temperature and a low-temperature circuit, wherein the secondary pump of the low-temperature circuit is driven by flow energy of the high-temperature circuit via a turbine wheel.

[0009] Against this background, the invention aims to provide technical solutions for conveying a coolant in a cooling circuit that reduce the effort required to design the cooling circuit to ensure the necessary coolant flows for different component configurations, as well as the effort required to assemble such cooling circuits, particularly the risk of component mix-ups. Furthermore, the coolant conveying efficiency should be increased and the required installation space reduced.

[0010] This problem is solved by a cooling circuit with the features of claim 1, by a motor vehicle with the features of claim 6, and by a method with the features of claim 9. Further particularly advantageous embodiments of the invention are disclosed in the respective dependent claims.

[0011] It should be noted that the features listed individually in the claims can be combined with one another in any technically meaningful way (even across category boundaries, for example between method and apparatus) and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0012] It should also be noted that the conjunction “and / or” used herein, which stands between two features and links them together, is always to be interpreted in such a way that in a first embodiment of the object according to the invention only the first feature may be present, in a second embodiment only the second feature may be present, and in a third embodiment both the first and the second feature may be present.

[0013] The invention relates to a cooling circuit for conveying a coolant (e.g., water or a water-glycol mixture) in a motor vehicle, comprising an upstream common cooling circuit section and a downstream common cooling circuit section, which are connected to each other via at least two parallel cooling circuit sections for distributing the coolant from the common cooling circuit sections to the parallel cooling circuit sections. A turbine wheel is rotatably arranged in each of the parallel cooling circuit sections and can be driven by the coolant flowing through the respective parallel cooling circuit section, the turbine wheels being rotationally fixed to each other. In other words, the turbine wheels are driven during operation of the cooling circuit, i.e.,while coolant is being pumped in the cooling circuit, it is set into a rotary motion by the coolant flowing in the respective parallel section of the cooling circuit.

[0014] The rotationally fixed coupling of the turbine wheels creates a self-regulating throttling of the coolant flow in the parallel cooling circuit sections. This ensures an evenly distributed coolant flow in both parallel cooling circuit sections under all operating conditions, i.e., at different operating temperatures and flow rates, as well as with different configurations of the cooling circuit or the respective parallel cooling circuit sections to the components being cooled in the vehicle. Designing the distribution of the coolant flows to the parallel cooling circuit sections, for example using conventional orifice plates as throttles, is unnecessary. Only the total flow rate in the cooling circuit, e.g., in the shared cooling circuit sections, needs to be considered. Fixed orifice plates in various configurations are therefore superfluous.Furthermore, flow energy can be transferred from one of the parallel-connected cooling circuit sections to other parallel-connected cooling circuit sections and is not lost as pressure loss. Accordingly, the efficiency of the cooling circuit according to the invention increases.

[0015] The cooling circuit of the invention offers high flexibility, as it can be operated independently of specific component configurations that influence the flow resistance of the coolant in the respective parallel-connected cooling circuit section. This, in turn, leads to significant savings in terms of the effort required for designing the cooling circuit to ensure the necessary coolant flows, as well as in assembly.

[0016] A coolant pump circulating the coolant in the cooling circuit can be designed for the lowest possible pumping capacity and reduced to a correspondingly smaller pump size. Ideally, the parallel sections of the cooling circuit can be circulated equally, even if they present different flow resistances to the coolant.

[0017] A turbine wheel is generally understood to be an element that converts the energy of the flowing coolant into mechanical rotational energy.

[0018] The turbine wheels are then rotationally fixed to each other if essentially no relative rotation between the turbine wheels is permitted and torque transmission takes place between the coupled turbine wheels.

[0019] In a preferred embodiment, the turbine wheels are mechanically coupled to each other via a common shaft in a rotationally fixed manner. In this way, the rotationally fixed coupling of the turbine wheels can be achieved in a reliable and compact design.

[0020] Alternative rotationally fixed couplings between the turbine wheels can be implemented in other embodiments based on hydraulic, electromechanical and / or electrohydraulic operating principles.

[0021] In further advantageous embodiments, each of the parallel-connected cooling circuit sections is designed for the operational cooling of different vehicle components. The number of components to be cooled in each parallel-connected cooling circuit section can also vary. The parallel-connected cooling circuit sections can exhibit different flow resistances for the coolant. The self-regulating throttling by means of the coupled turbine wheels leads to an automatic equalization of the coolant volume flow in the parallel-connected cooling circuit sections. The turbine wheel on whose blades the coolant flow exerts the higher torque automatically drives the coolant flow in the other parallel-connected cooling circuit sections.

[0022] In another advantageous embodiment, a speed sensor is provided for detecting the rotational speed of the turbine wheels. For example, the speed sensor can be arranged and configured to detect the rotational speed of the common shaft. The total current volumetric flow rate of the coolant conveyed through the cooling circuit can then be easily determined from the detected rotational speed of the turbine wheels.

[0023] In a particularly preferred further embodiment, a single coolant pump is provided in one of the common cooling circuit sections for pumping the coolant. The cooling circuit can be operated efficiently and requires little installation space.

[0024] The invention further relates to a motor vehicle comprising a cooling circuit for cooling at least two vehicle components, wherein the cooling circuit is configured according to one of the embodiments disclosed herein, and the at least one vehicle component is assigned to the at least one parallel-connected cooling circuit section, and the at least one other vehicle component is assigned to the at least one other parallel-connected cooling circuit section. The cooling circuit serves to cool the several vehicle components that require active cooling during operation of the motor vehicle, such as an actively cooled control unit for, e.g., infotainment and autonomous driving functions, as well as a further component.

[0025] In an advantageous embodiment, the motor vehicle has two drive axles, each with different drive components requiring cooling. Each drive axle is assigned one of the parallel cooling circuit sections of the cooling circuit for the operational cooling of the corresponding drive components.

[0026] For example, the motor vehicle can be designed as an all-wheel-drive battery electric vehicle (BEV), in which case each of the drive axles has at least one electric drive motor and one inverter to supply the corresponding drive motor with electrical energy as drive components that require cooling during operation.

[0027] The invention is not necessarily limited to all-wheel-drive motor vehicles. It can also be successfully applied in motor vehicles driven by fewer than all wheels. It should be understood that, with regard to vehicle-related definitions of terms and the effects and advantages of vehicle-specific features, reference can be made in full to the disclosure of analogous definitions, effects, and advantages of the cooling circuit according to the invention, and vice versa. A repetition of explanations of analogous features, their effects, and advantages can therefore be omitted in favor of a more concise description, without such omissions being to be interpreted as a limitation of any of the disclosed subject matter of the invention.

[0028] The invention further relates to a method for conveying a coolant in a cooling circuit of a motor vehicle, in which the coolant is conveyed from an upstream common cooling circuit section to a downstream common cooling circuit section and is divided in between into at least two parallel-connected cooling circuit sections which connect the two common cooling circuit sections to each other by means of coolant, wherein a turbine wheel rotatably arranged in the respective parallel-connected cooling circuit section is driven by the coolant flowing through the respective parallel-connected cooling circuit section, wherein the turbine wheels are coupled to each other in a rotationally fixed manner.

[0029] Regarding the process-related definitions, effects, and advantages, full reference can be made to the disclosure of analogous definitions, effects, and advantages of the cooling circuit according to the invention, and vice versa. A repetition of explanations of analogous features, their effects, and advantages can therefore be omitted in favor of a more concise description, without such omissions being interpreted as a limitation of any of the disclosed subject matter of the invention.

[0030] Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, which are not to be understood as limiting and are explained in more detail below with reference to the drawing. The drawing schematically shows: Fig. 1 a cooling circuit for conveying a coolant in a motor vehicle according to an embodiment of the invention; Fig. 2 a cutaway detail view of two rotationally fixed turbine wheels of the cooling circuit Fig. 1; and Fig. 3 A cutaway detail view of two rotationally fixed turbine wheels of a cooling circuit according to a further embodiment of the invention.

[0031] In the different figures, parts of equal value with regard to their function are always provided with the same reference symbols, so that they are usually only described once.

[0032] Fig. Figure 1 schematically represents a cooling circuit 10 for conveying a coolant in a motor vehicle 11 according to an embodiment of the invention.

[0033] In the illustrated embodiment, the motor vehicle 11 is designed as an all-wheel-drive battery-electric vehicle (BEV), but the invention is not necessarily limited to either battery-electric vehicles or all-wheel-drive vehicles. The invention is also applicable to motor vehicles driven by fewer than all wheels, as well as to non-battery-electric vehicles, e.g., conventionally powered vehicles with an internal combustion engine, which have vehicle components that require active cooling by the coolant during operation.

[0034] In any case, the motor vehicle 11 has Fig. 1 two drive axles 12 and 13, of which drive axle 12 is a front-wheel drive axle and drive axle 13 is a rear-wheel drive axle of the motor vehicle 11.

[0035] As in Fig. As shown in Figure 1, each drive axle 12, 13 has different drive components that require cooling. In particular, the front-drive axle 12 has an electric drive motor 12-1 and an inverter 12-2 (e.g., a pulse inverter) for supplying the electric drive motor 12-1 with electrical energy. The electric drive motor 12-1 and the inverter 12-2 are the drive components of the front-drive axle 12 that require cooling. The rear-drive axle 13 has an electric drive motor 13-1 and an inverter 13-2 (e.g., a pulse inverter) for supplying the electric drive motor 13-1 with electrical energy. The electric drive motor 13-1 and the inverter 13-2 are the drive components of the rear-drive axle 13 that require cooling.

[0036] Cooling circuit 10 has an upstream common cooling circuit section 14 and a downstream common cooling circuit section 15. These are connected to each other via at least two parallel cooling circuit sections 16-1 and 16-2 for the distribution of the coolant from the two common cooling circuit sections 14 and 15 to the parallel cooling circuit sections 16-1 and 16-2. A turbine wheel 17-1 and 17-2 is rotatably arranged in each of the parallel cooling circuit sections 16-1 and 16-2 (see Figure 1). Fig. 2) which can be driven by the coolant flowing through the corresponding parallel cooling circuit section 16-1 or 16-2 and is driven during the operation of cooling circuit 10, i.e., while the coolant is being pumped through cooling circuit 10. The turbine wheels 17-1 and 17-2 are rotationally fixed to each other.

[0037] In Fig. The turbine wheels 17-1 and 17-2 are housed in a common turbine casing 18. This casing is connected via coolant to a first upstream coolant inlet with the parallel cooling circuit section 16-1 and to a second upstream coolant inlet with the parallel cooling circuit section 16-2. A downstream coolant outlet of the turbine casing 18 connects it via coolant to the downstream common cooling circuit section 15.

[0038] The two common cooling circuit sections 14 and 15 carry a total coolant flow V̇. g , the parallel-connected cooling circuit sections 16-1 and 16-2 each have a partial volume flow V̇ F or V̇ H This applies to all component configurations: V˙g=V˙F+V˙H and V˙F=V˙H

[0039] This is achieved by the coupled turbine wheels 17-1 and 17-2, which are located in Fig. Figure 2 is shown schematically in a cutaway detail view. It can be seen that, in the present embodiment, the two turbine wheels 17-1 and 17-2 are rotationally fixed to each other via a common shaft 19. This ensures that the rotational speed of the turbine wheels 17-1 and 17-2 is always the same. With an ideally sealed turbine housing 18, the volume flow rates V̇ are therefore also constant. F and V̇ H The turbine wheel 17-1 or 17-2, on whose blades the coolant flow exerts the higher torque, drives the other side or the other turbine wheel 17-2 or 17-1, respectively. The rotationally fixed coupling of turbine wheels 17-1 and 17-2 achieves a self-regulating throttling of the coolant flowing in the parallel cooling circuit sections 16-1 and 16-2.

[0040] Fig. Figure 3 schematically depicts a cutaway detail view of the rotationally fixed turbine wheels 17-1 and 17-2 of a cooling circuit (not shown) according to a further embodiment of the invention. This cooling circuit can be essentially configured as in Fig. 1. Cooling circuit 10 shown. The essential difference of the one shown in Fig. 3. Part of the cooling circuit shown, compared to the one in Fig. The cooling circuit 10 shown in 1 is located in a speed sensor 20 which detects the rotational speed of the shaft 19.

[0041] This allows for a measurement of the total volume flow rate V̇. g This can be done, for example, using a conventional map-based control of the volume flow rate V̇. g can be replaced by sensor-based control, thus saving further application effort.

[0042] Reference is made again to Fig. Figure 1 shows that a coolant pump 21 is provided in the upstream common cooling circuit section 14 for pumping the coolant. This pump 21 is preferably the only coolant pump provided in the cooling circuit 10 for pumping the coolant.

[0043] Furthermore, Fig.It can also be seen from Figure 1 that each of the parallel-connected cooling circuit sections 16-1 and 16-2 is intended for the operational cooling of different components of the motor vehicle 11. In addition to the drive motor 12-1 and the inverter 12-2, the parallel-connected cooling circuit section 16-1 is also assigned, by way of example, a control unit 22, which is actively cooled by the coolant and is used for, for example, infotainment and autonomous driving functions. This control unit 22 is also a component of the motor vehicle 11 that requires operational cooling, but is not necessarily limited to the assignment to the parallel-connected cooling circuit section 16-1 shown here. The actively cooled control unit 22 can alternatively be assigned to the parallel-connected cooling circuit section 16-2.

[0044] In addition to the drive motor 13-1 and the inverter 13-2, another high-voltage component 23, which is actively cooled by the coolant, is assigned to the parallel-connected cooling circuit section 16-2, for example, a charger for the vehicle 11, a DC / DC converter, or similar. This component also represents a component of the vehicle 11 that requires cooling during operation, without necessarily being limited to the assignment to the parallel-connected cooling circuit section 16-2 shown here. Alternatively, the actively cooled high-voltage component 23 could be assigned to the parallel-connected cooling circuit section 16-1. REFERENCE MARK LIST: 10 Cooling circuit 11 Motor vehicle 12 front-wheel drive axles 12-1 Electric Drive Machine 12-2 Inverter 13 Rear-wheel drive axle 13-1 Electric drive motor 13-2 Inverter 14 Upstream common cooling circuit section 15 Downstream common cooling circuit section 16-1 Parallel connected cooling circuit section 16-2 Parallel connected cooling circuit section 17-1 Turbine wheel 17-2 Turbine wheel 18 turbine housings 19th wave 20 Speed ​​sensor 21 Coolant pump 22 Actively cooled control unit 23 High-voltage component requiring active cooling V̇ g Total volume flow V̇ F Partial volume flow V̇ H Partial volume flow

Claims

Cooling circuit (10) for conveying a coolant in a motor vehicle (11), comprising an upstream common cooling circuit section (14) and a downstream common cooling circuit section (15), which are connected to each other via at least two parallel-connected cooling circuit sections (16-1, 16-2) for distributing the coolant from the common cooling circuit sections (14, 15) to the parallel-connected cooling circuit sections (16-1, 16-2), wherein a turbine wheel (17-1, 17-2) is rotatably arranged in each of the parallel-connected cooling circuit sections (16-1, 16-2), which can be driven by the coolant flowing through the respective parallel-connected cooling circuit section (16-1, 16-2), wherein the turbine wheels (17-1, 17-2) are coupled to each other in a rotationally fixed manner. Cooling circuit according to claim 1, wherein the turbine wheels (17-1, 17-2) are mechanically coupled to each other in a rotationally fixed manner via a common shaft (19). Cooling circuit according to claim 1 or 2, wherein each of the parallel connected cooling circuit sections (16-1, 16-2) is provided for the operational cooling of different components (12-1, 12-2, 22; 13-1, 13-2, 23) of the motor vehicle (11). Cooling circuit according to one of the preceding claims, wherein a speed sensor (20) is provided for detecting a speed of the turbine wheels (17-1, 17-2). Cooling circuit according to one of the preceding claims, wherein a single coolant pump (21) is provided in one of the common cooling circuit sections (14) for pumping the coolant. Motor vehicle (11) comprising a cooling circuit (10) for cooling at least two vehicle components, wherein the cooling circuit (10) is designed according to one of the preceding claims and the at least one vehicle component is assigned to the at least one parallel connected cooling circuit section (16-1) and the at least one other vehicle component is assigned to the at least one other parallel connected cooling circuit section (16-2). Motor vehicle (11) according to claim 6, which has two drive axles (12, 13) each with different drive components (12-1, 12-2, 13-1, 13-2) to be cooled during operation, wherein each drive axle (12, 13) is assigned one of the parallel connected cooling circuit sections (16-1, 16-2) of the cooling circuit (10) for the operational cooling of the corresponding drive components (12-1, 12-2, 13-1, 13-2). Motor vehicle according to claim 7, which is designed as an all-wheel-drive battery-electric motor vehicle, wherein each of the drive axles (12, 13) has at least one electric drive motor (12-1, 13-1) and one inverter (12-2, 13-2) as drive components to be cooled during operation for supplying the respective drive motor (12-1, 13-1) with electrical energy. Method for conveying a coolant in a cooling circuit (10) of a motor vehicle (11), wherein the coolant is conveyed from an upstream common cooling circuit section (14) to a downstream common cooling circuit section (15) and is divided between them into at least two parallel-connected cooling circuit sections (16-1, 16-2) which connect the two common cooling circuit sections (14, 15) by means of coolant, wherein a turbine wheel (17-1, 17-2) rotatably arranged in the respective parallel-connected cooling circuit section (16-1, 16-2) is driven by the coolant flowing through the respective parallel-connected cooling circuit section (16-1, 16-2), wherein the turbine wheels (17-1, 17-2) are coupled to each other in a rotationally fixed manner.

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