DE102020200964A1 - Cooling system for cooling components - Google Patents

Abstract

Disclosed is a cooling system (10), in particular for an electrically drivable vehicle (100), having a primary refrigerant circuit (20) and a secondary refrigerant circuit (30) which are fluidly coupled to one another via at least one ejector (40), with the primary refrigerant circuit (20) a compressor (21) for driving the at least one ejector (40) with a refrigerant and a condenser / gas cooler (22) connected upstream of the at least one ejector (40), a first evaporator in the primary refrigerant circuit (20) (24) and a second evaporator (32) are arranged in the secondary refrigerant circuit (30), the first evaporator (24) being set up to provide a higher cooling capacity than a cooling capacity made available by the second evaporator (32). A vehicle (100) is also disclosed.

Description

The invention relates to a cooling system, in particular for an electrically drivable vehicle, having a primary refrigerant circuit and a secondary refrigerant circuit, which are coupled to one another in a fluid-conducting manner via at least one ejector. The invention also relates to a motor vehicle with such a cooling system.

Air conditioning systems designed as compression air conditioning systems are usually used for air conditioning vehicle interiors. A corresponding refrigerant circuit comprises a compressor, a condenser or gas cooler, an expansion valve and an evaporator. The refrigerant can be conveyed through the compressor. When flowing through the expansion valve, the liquid refrigerant is evaporated and fed into the evaporator, which can extract the heat from an environment and cool it. After passing through the evaporator, the refrigerant is compressed and converted into a liquid state by the condenser or gas cooler.

In the case of electrically powered vehicles, the traction battery must be cooled in addition to the vehicle interior. This leads to significantly increased demands on the performance of the air conditioning system. To enable comprehensive air conditioning of all components and the vehicle interior, more powerful air conditioning systems are usually used. Due to the increased performance, the components of the air conditioning system are heavier and require more space. Furthermore, the costs and energy consumption of the vehicle increase due to a more powerful air conditioning system.

Alternative air conditioning concepts accept impairment of comfort in the vehicle interior or overheating of the traction battery.

The invention is based on the object of creating an air conditioning system which enables a traction battery to be cooled efficiently and without additional consumption. This object is achieved by the features specified in claim 1. Further advantageous refinements of the invention are described in the subclaims.

According to one aspect of the invention, a cooling system, in particular for an electrically drivable vehicle, is provided. The vehicle can be an exclusively electrically driven vehicle or a supporting electrically driven vehicle, such as, for example, a hybrid vehicle. In particular, the vehicle can be configured as a passenger car, a truck, a utility vehicle, an agricultural vehicle and the like.

The cooling system has a primary refrigerant circuit and a secondary refrigerant circuit, which are coupled to one another in a fluid-conducting manner via at least one ejector. The primary and secondary refrigerant can be separated by a shut-off expansion valve.

For example, a separator can also distribute the refrigerant present in a liquid physical state into the secondary refrigerant circuit and the refrigerant present in a gaseous physical state into the primary refrigerant circuit. Alternatively or additionally, a gaseous refrigerant with a liquid component can also be fed into the primary refrigerant circuit. The separator can be arranged downstream of the at least one ejector.

A compressor is preferably arranged in the primary refrigerant circuit. The refrigerant of the primary refrigerant circuit thus serves as a drive for the at least one ejector. The at least one ejector acts as a jet pump for the refrigerant in the secondary refrigerant circuit.

A first evaporator is arranged in the primary refrigerant circuit and a second evaporator is arranged in the secondary refrigerant circuit. The first evaporator is preferably set up to provide a higher cooling capacity than a cooling capacity made available by the second evaporator.

Depending on the design of the refrigeration system, an expansion valve can be connected upstream of the first evaporator and / or the second evaporator. For example, an expansion valve can be provided upstream of the first evaporator in the direction of flow of the refrigerant in order to expand the liquid refrigerant as a gas and thus provide a particularly high cooling capacity through the second evaporator.

During operation, the at least one ejector generates a lower pressure in the second evaporator and thus a lower evaporation temperature level than in the first evaporator.

The at least one ejector can thus generate two different temperature levels, which are available to the cooling system as cooling power through the first evaporator and the second evaporator.

The cooling capacity of the two evaporators can be provided simultaneously and permanently with the operation of the cooling system. The first evaporator can also be operated alone, with the second evaporator can only be operated together with an operation of the first evaporator or the primary refrigerant circuit.

The first evaporator can preferably be used to provide a lower temperature with a high cooling capacity and the second evaporator can be used to provide a higher temperature with a low cooling capacity. Alternatively, the first evaporator can provide a lower cooling capacity than the second evaporator.

Due to the evaporation pressure, the second evaporator can have a lower temperature level than the first evaporator. However, the first evaporator has a higher cooling capacity than the second evaporator and can, for example, effectively cool a larger volume, such as the vehicle interior.

The cooling system according to the invention can provide an additional secondary refrigerant circuit which can be used for cooling further components without increasing the performance of the compressor or a larger compressor.

The secondary refrigerant circuit can enable a temperature level which is above a temperature level of the first evaporator. This higher temperature level of the second evaporator can be used particularly efficiently if the second evaporator is set up to cool at least one electrical component, such as a traction battery or power electronics. For example, the second evaporator can have a cooling capacity of 2 kW with a temperature level of 35 ° C.

The secondary refrigerant circuit enables, in particular, the provision of additional cooling capacity, which arises “free of charge” or without additional energy consumption by the compressor.

The primary refrigerant circuit can be used to increase the comfort of the vehicle if the first evaporator is configured to cool a vehicle interior. As a result, the higher cooling power of, for example, 5 kW compared to the second evaporator can be used to cool a larger volume, such as the vehicle interior or a cargo hold. The temperature resulting from the higher cooling capacity can be 2 ° C., for example.

According to a further exemplary embodiment, the compressor can be operated, regulated by a control device, with electrical power for generating a first cooling output in the first evaporator and a second cooling output in the second evaporator. The compressor can preferably be controlled by the control device in such a way that the resulting cooling capacity is adapted in accordance with an enthalpy difference obtained from the isentropic throttling. In particular, the compressor can be regulated by the control device in such a way that permanent cooling of a component, such as the traction battery, is provided in the form of additional cooling without additional consumption of the compressor. As a result, an electrically drivable vehicle can be operated in a particularly energy-efficient manner. The regulation of the cooling capacity can alternatively or additionally take place by means of at least one expansion valve.

The cooling system can be used for active thermal regulation of components if the control unit is connected to at least one temperature sensor for receiving measurement data. In particular, the compressor and / or an expansion valve for at least temporarily increasing the first cooling capacity and / or the second cooling capacity can be regulated by the control device if at least one temperature determined on the basis of the measurement data exceeds a temperature limit. The expansion valve can preferably be a controllable expansion valve with a variably adjustable expansion opening with an adjustable complete closure. By means of this measure, permanent operation with a reduced provided cooling capacity can at least temporarily be replaced by operation with an increased cooling capacity of the cooling system. This changeover can preferably take place when a temperature limit of the component is exceeded, which is, for example, 30 ° C., and enables a reaction to an impending overheating of the component.

As an alternative or in addition to regulation of the compressor by the control device, regulation of an inflow to the at least one ejector for generating a first cooling capacity in the first evaporator and a second cooling capacity in the second evaporator can also take place. The inflow to the at least one ejector can be controlled in such a way that the resulting cooling capacity is adapted in accordance with an enthalpy difference obtained from the isentropic throttling. As an alternative or in addition to controlling the inflow, a pressure or an inflow opening of the at least one ejector can also be set by the control device.

In a further additional or alternative embodiment, the first expansion valve and / or the second expansion valve are used by the control device to generate a first cooling capacity in the first evaporator and a second cooling capacity adjustable in the second evaporator. The first expansion valve and / or the second expansion valve are preferably controllable in such a way that the resulting cooling capacity is adapted in accordance with an enthalpy difference obtained from the isentropic throttling. As a result, the expansion valves can be designed to be electronically adjustable, which enables the control device to precisely regulate the resulting refrigerant pressure.

According to a further embodiment, the secondary refrigerant circuit has an expansion valve connected upstream of the second evaporator and / or the primary refrigerant circuit has an expansion valve connected upstream of the first evaporator, in particular with a shut-off function. As a result of this measure, the first evaporator and / or the second evaporator can be used particularly efficiently to provide cooling power.

A component cooling system or a battery cooling system can be operated without an increased power requirement of the compressor if the cooling capacity at the second evaporator is set in such a way that only the enthalpy difference obtained by the approximately isentropic expansion in the at least one ejector is used instead of the isenthalpic expansion.

According to a further aspect of the invention, a vehicle, in particular an electrically drivable vehicle, is provided. The vehicle has a vehicle interior and at least one electrical component, which are thermally connected to a cooling system according to the invention. A first evaporator of the cooling system can preferably be used for cooling the vehicle interior and a second evaporator of the cooling system can be used for cooling the component.

The component of the vehicle can be, for example, a traction battery, one or more electric motors, power electronics and the like.

The vehicle can be an exclusively electrically driven vehicle or a supporting electrically driven vehicle, such as, for example, a hybrid vehicle. In particular, the vehicle can be configured as a passenger car, a truck, a utility vehicle, an agricultural vehicle and the like.

• 1 eine schematische Darstellung eines Kühlsystems gemäß einer Ausführungsform, und
• 2 eine Seitenansicht eines Fahrzeugs mit einem Kühlsystem aus 1.

Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. Show it:

• 1 a schematic representation of a cooling system according to an embodiment, and
• 2 Figure 3 is a side view of a vehicle with a cooling system 1 .

In the figures, the same structural elements have the same reference numbers in each case.

In the 1 is a schematic representation of a cooling system 10 shown according to one embodiment. The cooling system 10 has a primary refrigerant circuit 20th and a secondary refrigerant circuit 30th on.

The primary refrigerant circuit 20th and the secondary refrigerant circuit 30th are via at least one ejector 40 Can be connected to one another in a fluid-conducting manner. A refrigerant of the primary refrigerant circuit is used here 20th as a drive means for the at least one ejector 40 , which is a refrigerant from the secondary refrigerant circuit 30th sucks.

One in the direction of flow S. the at least one ejector 40 downstream separator 50 serves to separate the refrigerant in the primary refrigerant circuit 20th and into the secondary refrigerant circuit 30th . The separator 50 can for example be designed as a separator and a refrigerant present in gaseous form to the primary refrigerant circuit 20th and a liquid refrigerant to the secondary refrigerant circuit 30th respectively.

The direction of flow S. of the refrigerant through the refrigerant circuits 20th , 30th is illustrated by arrows.

The primary refrigerant circuit 20th has a compressor 21 and a condenser or gas cooler 22nd on. The compressor 21 serves to convey the refrigerant along the primary refrigerant circuit 20th . In the condenser or gas cooler 22nd the gaseous refrigerant can be converted into a liquid state of aggregation before it enters the at least one ejector 40 can flow into it.

The separator 50 downstream is in the primary refrigerant circuit 20th a first expansion valve 23 arranged, which the refrigerant in a first evaporator 24 expand and thus generate a first cooling capacity.

After passing the first evaporator 24 the refrigerant continues through the compressor 21 promoted.

The secondary refrigerant circuit 30th has a separator 50 downstream second expansion valve 31 on, which the liquid refrigerant in a second evaporator 32 can expand and generate a second cooling capacity.

The refrigerant can then be used in the secondary refrigerant circuit 30th through the at least one ejector 40 , which by the refrigerant of the primary refrigerant circuit 20th is driven, sucked in and thus conveyed in a circle.

The cooling system 10 also has a control unit 60 on. The control unit 60 can be configured as an external control device, such as a vehicle control device, according to an alternative embodiment.

The control unit 60 is with one or more temperature sensors 70 connected and can thus receive measurement data. In particular, the control unit 60 carry out an active thermal management and the cooling system 10 actively influence.

The control unit 60 can directly access measurement data from a temperature sensor 70 or indirectly to measurement data from another component, such as a battery management system 71 , access.

To influence the first cooling capacity and the second cooling capacity, the control device 60 the compressor 21 control or regulate. Alternatively or additionally, the control unit 60 the first expansion valve 23 and / or the second expansion valve 31 control and thus the resulting temperatures in the first evaporator 24 and / or the second evaporator 32 steer.

the 2 Figure 3 shows a side view of a vehicle 100 with a cooling system 10 the end 1 . The vehicle 100 is designed, for example, as an electric vehicle and has a component designed as a traction battery 110 on.

The traction battery 110 has a temperature sensor 70 and a battery management system 71 on through which the control unit 60 of the cooling system 10 Traction battery temperature measurement data 110 can receive and determine a cooling capacity requirement.

The second evaporator 32 of the cooling system 10 is with the traction battery 110 thermally coupled and can therefore use the traction battery 110 cool.

The first vaporizer 24 of the cooling system 10 is set up to a vehicle interior 120 to cool. For this is the first evaporator 24 with a blower 130 connected and can therefore be used in the vehicle interior 120 cool the air supplied.

List of reference symbols

100

vehicle

110

Component / traction battery

120

Vehicle interior

130

fan

10

Cooling system

20th

primary refrigerant circuit

21st

compressor

22nd

Condenser or gas cooler

23

first expansion valve

24

first evaporator

30th

secondary refrigerant circuit

31

second expansion valve

32

second evaporator

40

Ejector

50

separator

60

Control unit

70

Temperature sensor

71

Battery management system

S.

Direction of flow of the refrigerant

Claims (10)

Cooling system (10), in particular for an electrically drivable vehicle (100), having a primary refrigerant circuit (20) and a secondary refrigerant circuit (30), which are coupled to one another in a fluid-conducting manner via at least one ejector (40), with the primary refrigerant circuit (20) a compressor (21) for driving the at least one ejector (40) by a refrigerant and a condenser / gas cooler (22) connected upstream of the at least one ejector (40), characterized in that a first evaporator is in the primary refrigerant circuit (20) (24) and a second evaporator (32) are arranged in the secondary refrigerant circuit (30), the first evaporator (24) being set up to provide a higher cooling capacity than a cooling capacity made available by the second evaporator (32). Cooling system after Claim 1 , wherein the second evaporator (32) is set up to cool at least one electrical component (110), such as a traction battery or power electronics. Cooling system after Claim 1 or 2 , wherein the first evaporator (24) is configured to cool a vehicle interior (120). Cooling system according to one of the Claims 1 until 3 , wherein the compressor (21) can be operated by a control device (60) with electrical power to generate a first cooling power in the first evaporator (24) and a second cooling power in the second evaporator (32), the compressor (21) being controllable in this way is that the resulting cooling capacity is adjusted according to an enthalpy difference obtained from the isentropic throttling. Cooling system according to one of the Claims 1 until 3 , wherein an inflow to the at least one ejector (40) can be controlled by the control device (60) to generate a first cooling power in the first evaporator (24) and a second cooling power in the second evaporator (32), the inflow to the at least an ejector (40) can be controlled in such a way that the resulting cooling capacity is adapted in accordance with an enthalpy difference obtained from the isentropic throttling. Cooling system according to one of the Claims 1 until 3 , wherein the first expansion valve (23) and / or the second expansion valve (31) can be regulated by the control device (60) for generating a first cooling capacity in the first evaporator (24) and a second cooling capacity in the second evaporator (32), the first Expansion valve (23) and / or the second expansion valve (31) can be controlled in such a way that the resulting refrigeration capacity is adapted in accordance with an enthalpy difference obtained from the isentropic throttling. Cooling system according to one of the Claims 1 until 6th , wherein the control device (60) is connected to at least one temperature sensor (70) for receiving measurement data, the compressor (21) and / or an expansion valve (23, 31) for at least temporarily increasing the first cooling capacity and / or the second cooling capacity can be regulated by the control device (60) when at least one temperature determined on the basis of the measurement data exceeds a temperature limit. Cooling system according to one of the Claims 1 until 7th , wherein the secondary refrigerant circuit (30) has an expansion valve (23, 31) connected upstream of the second evaporator (32) and / or the primary refrigerant circuit (20) has an expansion valve (23, 31) connected upstream of the first evaporator (24), in particular with a shut-off function. Cooling system according to one of the Claims 1 until 8th , wherein a second cooling power generated by the second evaporator (32) can be set to be less than or equal to a corresponding enthalpy difference obtained from the isentropic throttling of the at least one ejector (40). Vehicle (100), in particular an electrically drivable vehicle, having a vehicle interior (120) and at least one electrical component (110), which are thermally connected to a cooling system (10) according to one of the preceding claims.

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