Method for operating a cooling system

Abstract

Operating method for operating a cooling system for a motor vehicle, in particular for an electrically powered motor vehicle, wherein the cooling system comprises a first cooling circuit, a second cooling circuit and at least one refrigerant circuit, - wherein the first cooling circuit comprises at least a first component to be cooled and an indirect condenser arranged in two parallel sections, with a first switching point located at the first or second branching point, which controls the flow of a cooling medium into the first component to be cooled and the indirect condenser, - wherein the second cooling circuit includes at least one second component to be cooled and a chiller - wherein the first and second cooling circuits can be connected by means of a first and second connecting section, and at least at the first connecting section a second switching point is arranged which controls the flow of the cooling medium into the at least first connecting section, - wherein a third switching point is arranged in the second cooling circuit, which controls the flow of cooling medium into the chiller, - wherein in the first cooling circuit a cooler is arranged downstream of the second connecting section, and upstream of the cooler a fourth switching point is arranged, which controls the flow of the cooling medium into the cooler, characterized in that the first, second, third and fourth switching point is controlled at least as a function of an ambient temperature Tu.

Description

[0001] The invention relates to methods for operating a cooling system for a motor vehicle according to the preamble of the independent patent claim.

[0002] From DE 103 00 294 A1, a cooling system is known, comprising a first cooling circuit for dissipating heat from a first heat source, e.g., an electric motor, a transmission heat exchanger, or an electronic cooling plate. Furthermore, the cooling system has a second cooling circuit that includes a second heat source, such as an internal combustion engine. A heater core serves to heat the passenger compartment. The first and second cooling circuits, as well as the heater core, can be selectively connected to each other by means of valves. Several possible operating methods for the cooling system are described.

[0003] German patent DE 10 2019 207 993 A1 discloses a thermal management system for a vehicle with an electric drive unit and an electric storage unit. This system comprises a refrigerant circuit in which a refrigerant circulates, a heating circuit, and two coolant circuits in which a coolant circulates. The coolant circuits serve to regulate the temperature of the drive unit and the storage unit. Increased efficiency of the thermal management system, with a reduced number of components and a smaller installation space requirement, is achieved by integrating a chiller into the refrigerant circuit, which serves as a common chiller for both coolant circuits.

[0004] From US 2015 0 273 976 A1, a cooling system for a motor vehicle is known that has several cooling circuits which can be switched in different ways by means of switching valves in order to be able to operate the cooling system in different operating modes adapted to the cooling requirements of the motor vehicle.

[0005] The inventive method for operating a cooling system for a motor vehicle with the features of the independent claims has the advantage that two cooling circuits can not only be directly coupled to each other, but also, by connecting both cooling circuits to a refrigerant circuit via a chiller and an indirect condenser, heat or cold can be distributed and used in the motor vehicle as needed. This enables flexible management of heating and cooling of drive components and the passenger compartment of an electrically powered motor vehicle, keeping energy consumption for heating and cooling low in order to utilize the amount of energy stored in the vehicle for propulsion as much as possible. In this way, a large proportion of the relevant driving and operating conditions of a motor vehicle, in particular a battery-electric motor vehicle, are covered in various possible operating modes.

[0006] Therefore, methods for operating a cooling system for a motor vehicle, in particular for an electrically powered motor vehicle, are proposed here according to the features of claim 1 and the dependent claims.

[0007] The cooling system according to the invention for a motor vehicle, necessary for the operation of the inventive operating method, comprises a first cooling circuit and a second cooling circuit and at least one refrigerant circuit. Both cooling circuits are operated with the same cooling medium, which is usually water mixed with glycol. However, it is also conceivable to use other cooling media, such as low-viscosity oils or media specifically tailored to the application. The refrigerant circuit is operated with a suitable refrigerant that possesses the necessary properties for absorbing, transferring, and releasing heat within a refrigerant circuit.

[0008] The first cooling circuit includes, for example, at least one first coolant pump that can circulate the coolant in a suitable manner within the cooling circuit. The first cooling circuit also includes at least one component requiring temperature control, which, in a particularly inventive embodiment, can be an electric drive motor. It is also conceivable that further components requiring temperature control are arranged in the first cooling circuit, such as an inverter for generating alternating current for the electric drive motor, or other electrical power circuits that can dissipate heat during operation or charging of a motor vehicle, or that must first be heated up under certain ambient conditions so that the components reach an optimal operating mode.

[0009] The first cooling circuit also includes a heat exchanger designed as a radiator to transfer heat between the first cooling circuit and the ambient air. Coolant can thus flow through the radiator, exchanging heat with the ambient air. A fan can be mounted on the radiator to blow or draw ambient air over it, further enhancing heat exchange. The dynamic pressure generated while the vehicle is in motion, also known as airflow, also contributes to heat exchange. The first cooling circuit also includes a heat exchanger designed as an indirect condenser. The indirect condenser transfers heat between the first cooling circuit and a refrigerant circuit. The term "indirect condenser" is always used when the coolant circulating in a cooling circuit is used for heat transfer within the condenser.In contrast, direct condensers do not use a cooling medium circulating in a cooling circuit, but rather ambient air for heat exchange.

[0010] The at least one first component to be cooled and the indirect condenser are arranged in two parallel sections, with the sections splitting at a first junction point and rejoining at a second junction point. A first switching point is located at either the first or second junction point. This first switching point is designed to allow the cooling medium circulating in the first cooling circuit to be divided between the two sections. This allows the cooling medium to be directed, depending on the application, more into the at least first component to be cooled or into the indirect condenser. More cooling medium in the component to be cooled increases its cooling capacity. Conversely, regulating the cooling medium flow into the indirect condenser affects the refrigerant circuit connected to the indirect condenser.Increased cooling capacity for the indirect condenser, for example, improves the performance and efficiency of the evaporator, thus providing more cooling power for temperature control in the passenger compartment. Other components of the refrigerant circuit, such as the chiller and a heat pump heater, can also be positively affected.

[0011] The distribution of the cooling medium can be achieved, in particular, by a suitable switchable or controllable valve device. It is also conceivable that two switching points, each located within a section, could distribute the flow rate. For this to be possible, the corresponding valve devices provided at the switching points must be controllable.

[0012] The second cooling circuit includes, for example, at least one second coolant pump capable of circulating the coolant appropriately within the circuit. Like the first cooling circuit, the second cooling circuit includes at least one component requiring temperature control. In a preferred embodiment according to the invention, this component is a battery for storing electrical energy to power the vehicle. The battery is subject to stringent temperature control requirements, as this significantly impacts the vehicle's efficiency. The battery temperature must not be too low, but it must also not exceed certain temperature limits, even at high ambient temperatures and high power output. An ideal operating range for the battery is between 35°C and 45°C.However, other components requiring temperature control may also be located in this cooling circuit, such as an electronic unit for controlling driver assistance systems and / or other electronic components.

[0013] A heat exchanger designed as a chiller and located in the second cooling circuit transfers heat between the second cooling circuit and the refrigerant circuit.

[0014] The first and second cooling circuits can be connected by means of a first connecting section and a second connecting section. Preferably, a second switching point is arranged at the first connecting section. This second switching point allows the first connecting section to be configured such that a cooling medium circulating in the first cooling circuit flows completely or at least partially through the first connecting section. It would also be conceivable to arrange the second switching point in the second connecting section so that the flow of cooling medium into the second cooling circuit is controlled there. The second switching point can open or close the flow completely or only partially. Advantageously, however, the flow at the second switching point is either open or closed in order to connect or disconnect the two cooling circuits.Closed here means that the flow of cooling medium is largely prevented by a suitable valve device, although a slight leakage of up to 5% of the volume flow cannot be ruled out or tolerated. This applies to all switching points used in the cooling system.

[0015] The first connecting section is located downstream of the first component to be cooled in the first cooling circuit, and the second connecting section is located downstream of the first connecting section. The two connecting sections can be interconnected by a third connecting section, which includes a check valve. The check valve allows flow through the third connecting section in only one direction and blocks flow in the other. If the two cooling circuits are separated, the cooling medium in the second cooling circuit circulates through this third connecting section. When the cooling circuits are connected, the check valve directs the cooling medium in the desired direction, preventing it from immediately bypassing the second cooling circuit again via the third connecting section, as this would offer a lower flow resistance.

[0016] The cooler in the first cooling circuit is preferably located downstream of the second connecting section. Downstream of the second connecting section and upstream of the cooler is a third section of the first cooling circuit, in which a fourth switching point is located. This fourth switching point can connect the third section to the area upstream of the first branching point, bypassing the cooler at least partially, such that a cooling medium circulating in the first cooling circuit flows completely or at least partially through the first bypass section.

[0017] This allows the flow through the cooler to be controlled and the cooler to be switched off depending on the application, e.g. to heat the cooling circuit to a certain temperature or to partially or completely integrate the cooler to enable a high cooling effect from the ambient air.

[0018] In the second cooling circuit, a third switching point is located upstream of the chiller. This point connects a second bypass section, bypassing the chiller at least partially, such that the cooling medium circulating in the second cooling circuit flows completely or at least partially through this second bypass section. This allows the flow of cooling medium through the chiller to be controlled, thereby regulating the heat transfer between the second cooling circuit and the refrigerant circuit.

[0019] The chiller typically absorbs heat from the cooling circuit through the evaporation of the refrigerant. This allows the cooling circuit to be cooled selectively depending on ambient and operating conditions, which is particularly advantageous for cooling at least the second component requiring temperature control, such as the battery. It is also conceivable that, under colder ambient conditions, heat absorbed from the second cooling circuit, or from both the first and second cooling circuits, is transferred into the refrigerant circuit, where it can then be used by a heat pump heater to warm the passenger compartment.

[0020] The refrigerant circuit used in the cooling system includes, for example, at least one compressor capable of appropriately compressing the refrigerant. The compressor is preferably electrically driven.

[0021] Furthermore, at least one heat exchanger, designed as an evaporator, is integrated into the refrigerant circuit. This heat exchanger allows for heat transfer between the refrigerant circuit and the air flowing into the passenger compartment. Specifically, the evaporation of refrigerant cools the incoming air, thus enabling temperature control of the passenger compartment at high outside temperatures. The evaporator can also operate in a reheat mode, in which the air is cooled when the ambient humidity is high and then reheated by a heating system. This prevents the vehicle windows from fogging up.

[0022] The indirect condenser, already located in the first cooling circuit and already described, is also part of the refrigerant circuit and thus enables heat exchange between the first cooling circuit and the refrigerant circuit.

[0023] The chiller, located in the second cooling circuit and already described, is also part of the refrigerant circuit and thus enables heat exchange between the second cooling circuit and the refrigerant circuit.

[0024] An internal heat exchanger, used for internal heat transfer, can also be installed in the refrigerant circuit. This serves to transfer heat from different areas of the refrigerant circuit and can thus advantageously increase the efficiency of the refrigerant circuit.

[0025] The refrigerant circuit can also include a heat exchanger designed as a heat pump heater, which enables heat exchange between the refrigerant circuit and the air flowing into the passenger compartment. This heat pump heater, in particular, warms the air flowing into the passenger compartment by causing the refrigerant to condense in the heat exchanger.

[0026] The individual components in the first and second cooling circuits are connected to each other by suitable pipes and / or hoses. It is also conceivable that individual components are combined in a liquid management module. For example, pumps, valves, connecting sections, sensors, and even heat exchangers such as the chiller can be arranged in such a liquid management module. Individual fluid lines and guides can also be advantageously integrated into such a liquid management module.

[0027] The components used for control and switching, in order to realize the various switching points, can also be represented as switchable individual valves, as complex valve devices that can represent several switching positions in one valve body, or in another suitable way.

[0028] The components to be cooled can be arranged in series or in parallel in the two cooling circuits. Additional switching points may also be present, for example, to disconnect individual components from the cooling circuit or even to control the flow of coolant to a single component.

[0029] The heat exchangers in the cooling circuits and refrigerant circuits can be constructed in a variety of ways. For example, they can consist of individual tubes with fins positioned between them to transfer heat to the air flowing through them or to absorb heat from the air. Stacked heat exchangers, in which individual plates are stacked alternately to create flow channels for at least two fluids, can also be used, particularly for indirect condensers and chillers. These are all well-known designs and must be selected and configured appropriately for the specific application.

[0030] For the appropriate control and regulation of the switching points, sensors such as pressure or temperature sensors and control units are required, which receive the necessary sensor signals and send corresponding control signals to the individual components, especially switching points, in particular the switchable or controllable valves.

[0031] A cooling system designed in this way can be operated in different advantageous and inventive operating methods, which are proposed in the features of claim 1 and the dependent claims.

[0032] The various operating procedures depend significantly on the ambient conditions, in particular the ambient temperature Tu and / or the condition of the vehicle, such as the temperatures T1, T2 of the components to be cooled. The temperature T1 of the first component to be cooled, P1, is the temperature of the coolant at the inlet to the first component to be cooled, P1, or, if present, at the inlet to a further upstream third component to be cooled, P3.

[0033] The temperature T2 of the second component P2 to be tempered is the maximum material temperature occurring in the second component P2. In the preferred embodiment according to the invention, it is the maximum cell temperature of the battery.

[0034] A first operating procedure covers starting the vehicle at very cold ambient temperatures TU of less than -5°C to below -20°C. It is assumed that the second component to be heated is a battery for powering the vehicle, and that this battery is also very cold, with a temperature T2 close to or equal to the ambient temperature T. UThis operating procedure assumes a temperature of less than -5°C. The goal of this procedure is to raise the temperature of the battery and other vehicle components as quickly as possible. Heating the passenger compartment with heat from the cooling system is not a priority. At the first switching point, the flow rate is controlled so that no or a maximum of 5% of the coolant circulating in the first cooling circuit flows through the indirect condenser. This ensures that the coolant primarily flows through the first component to be heated, which in this case is assumed to be an electric drive motor with corresponding power electronics. Heat is absorbed by the drive motor. In this operating procedure, the second switching point is set so that the first connecting section is completely or almost completely open. The second cooling circuit is thus coupled to the second cooling circuit.This allows the heat absorbed by the drive motor to be used to heat the battery in the second cooling circuit. The third switching point in the second cooling circuit is configured so that the chiller is either not cooled at all or only minimally, in particular with less than 5% flow rate, and the majority of the circulating flow rate is routed through the second bypass section. The fourth switching point is configured so that the cooler is bypassed, meaning that little or no coolant (less than 5%) of the cooling medium flow rate is cooled by the ambient air and is routed past the cooler via the first bypass section. This distributes the heat from the cooling medium between the two cooling circuits and, in particular, transfers it to the battery.

[0035] A second operating method covers very cold ambient temperatures Tu below -5°C, particularly down to -20°C. The temperature T2 in the second component to be cooled, preferably the battery, has already reached a temperature greater than -5°C but still below 10°C. The vehicle has therefore already been in operation for some time, and the battery has absorbed or generated some heat. It is also conceivable that the battery has already been warmed up by a previous drive or charging process. However, the battery is still too cold for optimal operation, which requires a temperature T2 between 35°C and 45°C. The first component to be cooled, preferably the electric drive motor with power electronics, continues to heat the two cooling circuits. The two cooling circuits thus remain connected, and the radiator is bypassed. The capacitor is also not cooled.The chiller can absorb up to 30% of the volume flow, specifically between 5% and 30%, and thus transfer some of the heat to the refrigerant circuit. Within the refrigerant circuit, the heat supplied can then be used via the heat pump heater to warm the air flowing into the passenger compartment. The first switching point will close the flow to the condenser, allowing a maximum of 5% of the volume flow to pass through. The second switching point will be fully or almost fully open, and the third switching point controls the flow to the chiller such that up to 30%, specifically at least 5% and a maximum of 30%, of the volume flow passes through it. The fourth switching point closes the flow to the cooler, allowing a maximum of 5% of the volume flow to pass through.

[0036] In another operating procedure, the operation of the vehicle at ambient temperatures below 10°C is covered. The temperature T2 in the second component to be cooled, preferably the battery, is ideally within the range of 35°C to 45°C. The two cooling circuits are now no longer connected; the radiator is bypassed. The condenser is also not cooled. However, the chiller can absorb between 50% and 100% of the volume flow and thus transfer some of the heat to the refrigerant circuit. The battery is therefore cooled via the chiller, and heat is added to the refrigerant circuit, which can be used to heat the vehicle interior. The drive motor and the power electronics heat the first cooling circuit.The permissible temperatures for these components requiring temperature control are between 50°C and 70°C, so that until the lower limit temperature of 50°C is reached, there is no increased cooling requirement for the components. The cooler therefore remains disconnected.

[0037] In a further operating procedure, the operation of the vehicle at ambient temperatures below 10°C is covered. The temperature T2 in the second component to be cooled, preferably the battery, is in an ideal range of 35°C to 45°C. The temperature in the first component to be cooled, preferably the electric drive motor and / or power electronics, is above 50°C. The battery is in an optimal operating mode and is cooled via the chiller by transferring heat into the refrigerant circuit. The transferred heat can then be used to heat the passenger compartment. The first and second cooling circuits are separate. The electric drive motor and the power electronics must now be cooled to prevent overheating.

[0038] The cooler is now integrated into the first cooling circuit to enable cooling via ambient air. If the waste heat from the refrigerant circuit exceeds the heating requirements of the vehicle interior, a portion of the flow is also routed through the condenser. The condenser releases excess heat from the refrigerant circuit, which is then used to cool the battery via the chiller. The first switching point controls the flow rate so that up to 25%, specifically more than 5% and less than 25%, of the flow reaches the condenser; the second switching point closes the circuit completely or almost completely; the third switching point controls the flow rate to the chiller so that between 50% and 100% of the flow rate passes through it; and the fourth switching point controls the flow rate to the radiator so that up to 30%, specifically more than 5% and less than 30%, of the flow rate passes through it.

[0039] In another operating procedure, the operation of the vehicle is covered at ambient temperatures between -5°C and 10°C. The temperature T2 in the second component to be cooled, preferably the battery, is within a range of -5°C to 10°C. The first and second cooling circuits are connected. The chiller transfers some of the heat to the refrigerant circuit, thus providing heat for heating the passenger compartment via a heat pump heater. The radiator is not cooled, meaning that the heat released in the second component to be cooled is used to further heat the battery and generate heat for the passenger compartment. Consequently, the condenser located in the first cooling circuit is also not cooled. Therefore, the first switching point closes the flow to the condenser so that a maximum of 5% of the volume flow passes through, and the second switching point opens completely or almost completely.The third switching point controls the flow to the chiller, ensuring that up to 30%, specifically more than 5% and less than 30% of the volume flow passes through it. The fourth switching point closes the flow to the chiller, allowing a maximum of 5% of the volume flow to pass through.

[0040] In a further operating procedure, the operation of the vehicle is covered at ambient temperatures between 10°C and 25°C. The temperature T2 in the second component to be temperature-controlled, preferably the battery, is within a range of 10°C to 25°C. The battery is not yet operating within its optimal temperature range. Therefore, the heat emitted from the first component to be temperature-controlled, particularly from the electric drive motor and power electronics, is used to heat the battery. The battery itself, however, already transfers heat via the chiller to the refrigerant circuit, which is used to heat the vehicle interior. An evaporator, advantageously arranged in the refrigerant circuit, is also in operation. The evaporator can thus cool the air flowing into the passenger compartment. After cooling, the air is then reheated in a heat pump heater or another heating device.This is also called reheat mode and serves to dry the incoming air when the ambient humidity is high. As the air cools in the evaporator, moisture is removed. This prevents the windshield from fogging up, especially at ambient temperatures below 20°C and high humidity. The operation of the evaporator also creates a cooling requirement at the condenser, which is why it is integrated into the first cooling circuit. However, the radiator is still largely inactive, so the heat transferred via the condenser can be used to heat the battery. Thus, the first switching point controls the flow rate so that up to 50%, and specifically more than 5% and less than 50%, of the volume flow reaches the condenser. The second switching point opens the flow completely or almost completely.The third switching point controls the flow to the chiller such that up to 50%, specifically more than 5% and less than 50%, of the volume flow passes through the chiller. The fourth switching point closes the flow to the chiller, so that a maximum of 5% of the volume flow passes through.

[0041] In another operating procedure, the operation of the vehicle is covered at ambient temperatures between 25°C and 35°C. The temperature T2 in the second component to be cooled, preferably the battery, is within this range. The battery has not yet reached its optimal operating temperature, but the vehicle interior already requires cooling. The two cooling circuits are connected. Thus, the first component to be cooled still contributes to heating the battery. However, the chiller no longer transfers heat to the refrigerant circuit, as there is no longer a need for heat to warm the passenger compartment, and no cooling effect from the chiller on the cooling circuit is desired. The condenser is also integrated into the cooling circuit because the evaporator in the refrigerant circuit is active for cooling the interior, resulting in heat generation in the condenser.Thus, the first switching point controls the flow rate so that up to 50%, and specifically more than 5% and less than 50%, of the volumetric flow reaches the condenser. The second switching point opens the flow completely or almost completely. The third switching point closes the flow to the chiller, allowing a maximum of 5% of the volumetric flow to pass through. The fourth switching point also closes the flow to the cooler, allowing a maximum of 5% of the volumetric flow to pass through.

[0042] In another operating procedure, the operation of the vehicle is covered at ambient temperatures between 10°C and 45°C. The temperature T2 in the second component to be cooled, preferably the battery, is in the range of 35°C to 45°C. The battery has reached its optimal operating temperature range. The two cooling circuits are connected, and the chiller is active. An additional cooling requirement arises at the condenser, either due to reheating of the evaporator or pure cooling of the evaporator within the refrigerant circuit. For this purpose, the radiator is now partially integrated to dissipate excess heat from the cooling circuits to the environment. Thus, the first switching point controls the flow rate so that up to 50%, and in particular more than 5% and less than 50%, of the volume flow reaches the condenser.

[0043] The second switching point closes completely or almost completely. The third switching point controls the flow to the chiller such that up to 50%, specifically more than 5% and less than 50%, of the volume flow is directed through the chiller. The fourth switching point controls the flow to the cooler such that up to 50%, specifically more than 5% and less than 50%, of the volume flow is directed through the cooler.

[0044] Further advantageous embodiments of the invention are described by the following figure descriptions. These show: Fig. 1 Overview of a cooling system according to the invention for a motor vehicle Fig. 2. Overview of another cooling system according to the invention for a motor vehicle Fig. 3 Another cooling system according to the invention for a motor vehicle in overview, wherein the two cooling circuits are coupled and the radiator is bypassed. Fig. 4. Overview of another cooling system according to the invention for a motor vehicle, wherein the two cooling circuits are coupled and the radiator and chiller are bypassed. Fig. 5. An overview of another cooling system according to the invention for a motor vehicle, wherein some switching points are combined in one module. Fig. 6. Schematic representation of the control logic of the cooling system Preferred embodiment of the invention

[0045] The Fig. Figure 1 shows a cooling system 1 according to the invention for a motor vehicle 2 in schematic form. It consists of a first cooling circuit K1, a second cooling circuit K2, and a refrigerant circuit K3. The cooling system 1 is located in a motor vehicle 2 and is responsible for temperature control of all important components P1, P2, P3, P4, such as the drive motor, power electronics, battery, or electronic control units or computing units for implementing autonomous driving functions. The first cooling circuit K1 contains a first component P1, and at least one further component P3 could also be located there. The first cooling circuit K1 also includes a first coolant pump 3 and a radiator 11. A fan 12 is arranged within range of the radiator 11, which can draw or blow ambient air L1 through the radiator 11 as needed, thus producing a cooling effect.The coolant pump 3 serves to circulate the cooling medium through the first cooling circuit K1. An indirect condenser 5 is also arranged in the first cooling circuit K1.

[0046] The first component to be tempered, P1, and the indirect capacitor 5 are arranged in two parallel sections A1 and A2, wherein sections A1 and A2 are divided at a first branching point 17 and joined at a second branching point 20. Fig. Here, at the second branch point 20, the first switching point V1 is located, which allows the cooling medium circulating in the first cooling circuit K1 to be divided between the two sections A1 and A2. However, it is also conceivable to arrange this first switching point V1 at the first branch point. This allows cooling medium to be directed, as needed, to the first and third components to be temperature-controlled, P1 and P3, and / or to the indirect condenser 5. The distribution ratio depends on the current operating conditions prevailing in the vehicle 2. In the indirect condenser 5, the cooling medium primarily serves to dissipate heat from the refrigeration circuit K3. This becomes necessary when the refrigeration circuit K3 is used for cooling the passenger compartment or for cooling the at least second component P2, which is advantageously a battery for storing energy to power the vehicle 2.

[0047] Thus, at cold ambient temperatures Tu or when the vehicle 2 is started, the indirect condenser 5 is usually not circulated through, but the cooling medium is only passed through the first component to be cooled, P1. This leads to a warming of the cooling medium. In the Fig. 1. In the cooling system 1 shown and operating point, both the indirect condenser 5 and the first section A1 are supplied with a partial flow of the cooling medium.

[0048] The second cooling circuit K2 includes at least one second coolant pump 4, which can circulate the cooling medium in a suitable manner within the second cooling circuit K2. Like the first cooling circuit K1, the second cooling circuit K2 includes at least one first component P2 to be temperature controlled. In a preferred embodiment according to the invention, this is a battery for storing the electrical energy for powering the motor vehicle 2. Fig. In the second cooling circuit, another component P4, such as an electronic unit for controlling driver assistance systems and / or other electronic components, is located. A heat exchanger designed as a chiller 6 is also located in the second cooling circuit.

[0049] The first cooling circuit K1 and the second cooling circuit K2 can be connected by means of a first connecting section 9 and a second connecting section 10. A second switching point V2 is arranged on the first connecting section 9. The second switching point V2 could also be arranged on the second connecting section 10. The second switching point V2 allows the first connecting section 9 to be connected in such a way that a cooling medium circulating in the first cooling circuit K1 flows completely or at least partially through the first connecting section 9. The first connecting section 9 is arranged downstream of the first component P1 to be cooled in the first cooling circuit K1, and the second connecting section 9 is arranged downstream of the first connecting section 10. The two connecting sections 9 and 10 are connected to each other by a third connecting section 14, which includes a check valve 15.The check valve 15 allows flow through the third connection section 14 in only one direction and blocks flow in the other direction. Thus, when the second switching point V2 is closed, the cooling medium in the second cooling circuit K2 circulates via the check valve 13 in the third connection section 14. When the second switching point V2 is opened, the cooling medium from the first cooling circuit K1 circulates through the first connection section 9 and, due to the check valve 13, cannot flow through the third connection section 14. It therefore circulates once in the second cooling circuit K2 and exits through the second connection section 10 back into the first cooling circuit K1.

[0050] The cooler 11, located in the first cooling circuit K1, is situated downstream of the second connecting section 10. Downstream of the second connecting section 10 and upstream of the cooler 11 is a third section A3 of the first cooling circuit K1, in which a fourth switching point V4 is located. A first bypass section 15, which can be switched by the fourth switching point V4, connects the third section A3 to the area upstream of the first branching point 17.

[0051] This fourth switching point V4 connects the third section A3 with the area upstream of the first branching point 17, so that a cooling medium circulating in the first cooling circuit K1 flows completely or at least partially through the first bypass section 15. This allows the cooler 11 to be completely or partially bypassed, thus regulating the cooling capacity of the first cooling circuit K1 via the ambient air L1. If a large amount of heat needs to be dissipated from the first cooling circuit K2, the cooler 11 can be selectively supplied with coolant to remove excess heat from the cooling system 1. By connecting the first and second cooling circuits K1 and K2, heat from the second cooling circuit K2 can also be dissipated directly via the ambient air L1 when required. Fig. 1 The fourth switching point V4 is switched in such a way that a partial current is routed via the cooler 11 and through the first bypass section 15.

[0052] In the second cooling circuit K2, a third switching point V3 is arranged upstream of the chiller 6. This switching point connects a second bypass section 16, at least partially bypassing the chiller 6, such that a cooling medium circulating in the second cooling circuit K2 flows completely or at least partially through the second bypass section 16. This allows the flow of cooling medium through the chiller 6 to be controlled and the heat transfer between the second cooling circuit K1 and the refrigerant circuit K3 to be regulated. Fig. The third switching point V3 is controlled such that a partial current is routed through both the chiller 6 and the bypass section 16. The chiller 6 absorbs heat from the second cooling circuit K2 by evaporating the refrigerant. Thus, the second cooling circuit K2 can be cooled selectively depending on ambient and operating conditions, which is advantageous for battery cooling.

[0053] The refrigerant circuit K3 arranged in the cooling system 1 includes a compressor 7. Preferably, this compressor 7 is electrically driven. Furthermore, a heat exchanger designed as an evaporator 8 is also arranged in the refrigerant circuit K3, which can exchange heat between the refrigerant circuit K3 and the air L2 flowing into the passenger compartment. Through the evaporation of refrigerant, the air L2 flowing into the passenger compartment can be cooled, thus enabling the temperature control of the passenger compartment at high outside temperatures Tu. A reheat function to dry incoming humid air L2 is also possible. In this process, the air L2 is first cooled so that moisture is removed, and then reheated by a subsequent heater, e.g., a heat pump heater 18. This heat pump heater 18 enables heat exchange between the refrigerant circuit K3 and the air L2 flowing into the passenger compartment.Thus, air L2 flowing into the passenger compartment is heated by the condensation of the refrigerant in the heat pump heater 18.

[0054] The previously described indirect condenser 5 is also part of the refrigerant circuit K3 and thus enables heat exchange between the first cooling circuit K1 and the refrigerant circuit K3. The previously described chiller 6, located in the second cooling circuit K2, is also part of the refrigerant circuit K3 and thus enables heat exchange between the second cooling circuit K2 and the refrigeration circuit K3. An internal heat exchanger 19 serves to transfer heat and can transfer heat from various areas of the refrigerant circuit K3. This increases the efficiency of the refrigerant circuit K3.

[0055] The individual components of the cooling circuits K1, K2 and the refrigerant circuit K3 are fluidically connected to each other by suitable hose or pipe connections.

[0056] Cooling system 1 also includes temperature sensors 21, 22, 23 for measuring the ambient temperature T U , as well as the temperatures and T2 at the components P1, P2 to be tempered. The temperature sensor 21 for measuring the ambient temperature Tu is attached to the motor vehicle 2 in a suitable location so that the ambient temperature Tu can be measured without direct sunlight or other direct heat sources.

[0057] The temperature sensor 22 is located in the coolant flow at the inlet to the first component P1 to be cooled. If further components to be cooled, such as the third component P3, are arranged upstream of the first component P1, the temperature sensor 22 is located in the coolant flow at the inlet of the most upstream component. The temperature sensor 23 is located in the second component P2 to be cooled in thermally conductive contact with the material of component P2. The position of the temperature sensor 23 is to be selected such that the measured temperature T2 corresponds to the maximum material temperature occurring in the second component P2. In the preferred embodiment according to the invention, this is the maximum cell temperature of the battery. The temperature sensors transmit the measured signals to a suitable control unit 24, which, for example,directly or via another vehicle control unit 26 of the motor vehicle 2, performs the necessary switching operations of the switching points V1, V2, V3, V4 in the cooling system 1.

[0058] The Fig. Figure 2 shows the cooling system 1 according to the invention at a specific operating point. In contrast to the system described in Figure 2, the following applies: Fig. At the operating point shown in Figure 1, the chiller 6 in the second cooling circuit K2 is completely or predominantly flowed through by the cooling medium. The third switching point V3 is set so that most of the cooling medium passes through the chiller 6. The two cooling circuits K1 and K2 are separate. The second switching point V2 is configured so that the first connecting section 9 is not flowed through. Thus, the first and second cooling circuits K1 and K2 are not connected to each other. In the second cooling circuit K2, the cooling medium therefore circulates via the third connecting section 14, the check valve 13, and through the components to be cooled P2, P4, and the chiller 6.

[0059] The Fig. Figure 3 shows the cooling system 1 according to the invention at a further operating point, where the first and second cooling circuits K1 and K2 are connected. The cooling medium can thus flow from the first cooling circuit K1 into the second cooling circuit K2, and from there into the components P2 and P4 to be cooled. It then flows in a first partial flow through the chiller 6, and in a second partial flow through the second bypass section 16, before exiting the second cooling circuit K2 back into the first cooling circuit K1. The fourth switching point closes the flow to the cooler 11, so that no fluid flows through it and the cooling medium is routed via the first bypass section 15. A closed flow means that only a volume flow of less than 5% is permitted, which flows through the cooler 11 as permissible leakage.The indirect capacitor 5, as well as the first component to be tempered P1, are each controlled by the first switching point V1 and flooded with partial currents.

[0060] The Fig. Figure 4 shows the cooling system 1 according to the invention at a further operating point. The first and second cooling circuits K1 and K2 are also connected here. The cooler 11 is not supplied with coolant; instead, the coolant is routed through the first bypass section 15. The fourth switching point V4 is switched accordingly. The chiller 6 is now no longer supplied with coolant. No heat can now be exchanged between the second cooling circuit K2 and the refrigerant circuit K3. The first component to be cooled, P1, and the third component to be cooled, P3, are now arranged in parallel to each other. A fifth switching point V5, which is arranged at a branch to the parallel circuits, makes it possible to selectively integrate the two components to be cooled, P1 and P3, into the first cooling circuit K1.It would thus be possible to further divide the flow rate of the cooling medium between the two components P1 and P3 according to a specific distribution ratio. This allows for the increased cooling requirements of a single component P1 or P3 to be accommodated, or, for example, for one of the components P1 or P3 to be completely excluded from cooling if no cooling is required. This reduces the flow resistance in the cooling circuit K1 and can therefore also increase efficiency.

[0061] The Fig. Figure 5 shows another cooling system according to the invention, wherein several switching points V1, V2, V4, as well as the check valve 12, and the connecting sections 9, 10, 14 are combined in a liquid management module 25. This means that the control functions of the individual switching points V1, V2, V4 are implemented in a single control valve or in several individual components arranged side by side in a liquid management module 25, in particular 3 / 2-way valves or other controllable valves. The connecting sections 9, 10, 14 are also integrated into the liquid management module 25 and could be structurally integrated, for example, into the supporting elements of the liquid management module 25, or attached directly to the liquid management module 25 as fixed hose or pipe connections. The check valve 13 can also be structurally integrated into the liquid management module, for example, by means of an inserted component.The idea of ​​a liquid management module 25 as an integrated component can be further developed and, for example, supplemented by the inclusion of the coolant pumps 3, 4 or the chiller 6, or by additional switching points and sensor elements. The wiring and operating points described here are not affected by the design, but merely represent further possible embodiments of the invention.

[0062] The Fig. Figure 6 shows a schematic representation of the control logic of cooling system 1, which is used to execute the procedure for operating the cooling system 1 of the motor vehicle 2. The temperatures are used as necessary input variables T. UT1, T2 are shown. The control unit 24 processes this input data and sends corresponding control commands to the control points V1, V2, V3, V4. A vehicle control unit 26 could serve as an additional data source or control aid, for example, to include further parameters of the vehicle 2 in the control of the cooling system 1. For instance, a control logic could also proactively influence the cooling system 1 before an uphill climb, which is detected by navigation data, or even include other operating parameters of the vehicle. The exact structure of the electronic control logic 24, 26 will not be described here. It is also conceivable to use several control units that communicate with each other or to process all data centrally and then distribute the corresponding control commands via a bus system.The structural and electrical design of this control system cannot therefore be fully described here. Reference symbol list 1 Cooling system 2 motor vehicles 3 First coolant pump 4 Second coolant pump 5 Indirect capacitor 6 Chiller 7 Compressor 8 evaporators 9 First connecting section 10 Second connecting section 11 coolers 12 fans 13 Check valve 14 Third connecting section 15 First bypass section 16 Second bypass section 17 First branching point 18 heat pump heaters 19 Internal heat exchanger 20 Second junction 21 Ambient temperature sensor 22 First internal temperature sensor 23 Second internal temperature sensor' 24 Control unit 25 Liquid Management Module 26 Vehicle Control Unit A1 section A2 section A3 section K1 First cooling circuit K2 Second cooling circuit K3 Refrigerant circuit P1 First component to be tempered P2 Second component to be tempered P3 Third component to be tempered P4 Fourth component to be tempered L1 Ambient air L2 Air flowing into the passenger compartment V1 First switching point V2 Second switching point V3 Third switching point V4 Fourth shift point V5 Fifth shift point Ambient temperature, temperature in the first component to be tempered T2 temperature in the second component to be tempered

Claims

[1] Method for operating a cooling system (1) for a motor vehicle (2), in particular for an electrically powered motor vehicle, wherein the cooling system comprises a first cooling circuit (K1), a second cooling circuit (K2) and at least one refrigerant circuit (K3), - wherein the first cooling circuit (K1) uses at least one first component to be cooled (P1) and an indirect condenser (5) arranged in two parallel sections (A1, A2), with a first switching point (V1) located at the first or second branch point (17, 20) which controls the flow of a cooling medium into the first component to be cooled (P1) and the indirect condenser (5), - wherein the second cooling circuit (K2) uses at least one second component to be cooled (P2) and a chiller (6). - wherein the first and second cooling circuits (K1,K2) are connected by means of a first and second connecting section (9,10), and at least at the first connecting section (9) a second switching point (V2) is arranged which controls the flow of the cooling medium into the at least first connecting section (9), - wherein a third switching point (V3) is arranged in the second cooling circuit (K2), which controls the flow of cooling medium into the chiller (6), - wherein in the first cooling circuit (K1) downstream of the second connecting section (10) a cooler (11) is arranged, and upstream of the cooler (11) a fourth switching point (V4) is arranged, which controls the flow of the cooling medium into the cooler (11), - wherein the first, second, third and fourth switching points (V1, V2, V3, V4) are controlled at least as a function of an ambient temperature Tu and as a function of a temperature T1, T2 of the first and / or second component to be tempered (P1, P2), characterized by, that at an ambient temperature Tu of less than -5°C and a temperature T2 in the second component to be tempered (P2) of less than -5°C, the first switching point (V1) closes the flow to the condenser (5) and the second switching point (V2) opens completely or almost completely, the third switching point (V3) closes the flow to the chiller (6) and the fourth switching point (V4) closes the flow to the cooler (11). [2] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by , that at the ambient temperature T Uof less than -5°C and the temperature T2 in the second component to be tempered (P2) between -5°C and 10°C, the first switching point (V1) closes the flow to the condenser (5) and the second switching point (V2) opens completely or almost completely, and the third switching point (V3) controls the flow to the chiller (6) such that up to 30%, in particular more than 5% and up to 30% of the volume flow is directed through the chiller (6) and the fourth switching point (V4) closes the flow to the cooler (11). [3] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu of less than 10°C and a temperature T2 in the second component to be cooled (P2) between 35°C and 45°C, the first switching point (V1) closes the flow to the condenser (5) and the second switching point (V2) closes, and the third switching point (V3) controls the flow to the chiller (6) such that between 50% and 100% of the volume flow is directed through the chiller (6) and the fourth switching point (V4) closes the flow to the cooler (11). [4] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu of less than 10°C, a temperature T2 in the second component to be cooled (P2) between 35°C and 45°C, and a temperature in the first component to be cooled (P1) of more than 50°C, the first switching point (V1) controls the flow rate such that up to 25%, in particular more than 5% and less than 25% of the volume flow rate reaches the condenser (5) and closes the second switching point (V2), and the third switching point (V3) controls the flow rate to the chiller (6) such that between 50% and 100% of the volume flow rate is directed through the chiller (6), and the fourth switching point (V4) controls the flow rate to the cooler (11) such that up to 30%, in particular more than 5% and less than 30% of the volume flow rate is directed through the cooler (11). [5] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu between -5°C and 10°C and a temperature T2 in the second component to be tempered (P2) between -5°C and 10°C, the first switching point (V1) closes the flow to the condenser (5) and the second switching point (V2) opens completely or almost completely, and the third switching point (V3) controls the flow to the chiller (6) such that up to 30%, in particular more than 5% and less than 30% of the volume flow is directed through the chiller (6), and the fourth switching point (V4) closes the flow to the cooler (11). [6] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu between 10 °C and 25 °C and a temperature T2 in the second component to be cooled (P2) between 10 °C and 25 °C, the first switching point (V1) controls the flow rate such that up to 50%, in particular more than 5% and less than 50% of the volume flow rate reaches the condenser (5) and opens the second switching point (V2) completely or almost completely, and the third switching point (V3) controls the flow rate to the chiller (6) such that up to 50%, in particular more than 5% and less than 50%, of the volume flow rate is directed through the chiller (6), and the fourth switching point (V4) closes the flow rate to the cooler (11). [7] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu between 25 °C and 35 °C and a temperature T2 in the second component to be cooled (P2) between 25 °C and 35 °C, the first switching point (V1) controls the flow rate such that up to 50%, in particular more than 5% and less than 50% of the volume flow reaches the condenser (5), and the second switching point (V2) opens completely or almost completely, and the third switching point (V3) closes the flow rate to the chiller (6) completely or almost completely, and the fourth switching point (V4) closes the flow rate to the cooler (11). [8] Method for operating a cooling system (1) having the features of the preamble of claim 1, characterized by, that at an ambient temperature Tu between 10 °C and 45 °C and a temperature T2 in the second component to be cooled (P2) between 35 °C and 45 °C, the first switching point (V1) controls the flow rate such that up to 50%, in particular more than 5% and less than 50% of the volume flow rate reaches the condenser (5), and the second switching point (V2) closes completely or almost completely, and the third switching point (V3) controls the flow rate to the chiller (6) such that up to 50%, in particular more than 5% and less than 50% of the volume flow rate reaches the chiller (6), and the fourth switching point (V4) controls the flow rate to the cooler (11) such that up to 50%, in particular more than 5% and less than 50% of the volume flow rate passes through the cooler (11). [9] Method according to any one of the preceding claims, characterized by, that the at least first component to be cooled (P1) in the first cooling circuit (K1) is an electric drive motor and that the at least second component to be cooled (P2) in the second cooling circuit (K2) is a battery for storing the electrical energy for driving the motor vehicle (1).

Images