DE102021202339A1 - Cooling device for a motor vehicle - Google Patents

Abstract

The present development relates to a cooling device (10) for a motor vehicle (1) comprising: - a first circuit (11) which has a compressor (12), a condenser (13), a first expansion element (14) and an evaporator (15) has, - a second circuit (21), which is thermally coupled to an energy store (40) and via a heat exchanger (20) to the first circuit (11), - a suction jet pump (30), which is in the first circuit (11) upstream of the compressor (12) and downstream of the heat exchanger (20).

Description

technical field

The present disclosure relates to a cooling device for a motor vehicle, in particular an air conditioning system and a cooling device for cooling a traction battery of an electrically operated motor vehicle.

background

For a long service life and efficient operation of motor vehicle batteries in a motor vehicle, it is necessary to operate the battery within a specified temperature window. At low temperatures, the battery must be heated or heated. Such motor vehicle batteries often have to be cooled, however. It is from the prior art, for example from EP 3 010 750 B1 known in principle to cool a high-voltage storage device by means of an air conditioning system provided in the motor vehicle

Furthermore, from the FR 3 077 242 B1 a cooling circuit for a motor vehicle is known, which is designed and provided for cooling the motor vehicle interior as well as for cooling a vehicle battery.

In contrast, the present development is based on the object of providing a cooling device for a motor vehicle, in particular for an electrically operated motor vehicle. The cooling device should be characterized by particularly efficient and energy-saving operation. The objective here is to reduce the temperature of an evaporator for controlling the temperature of the motor vehicle interior.

This object is achieved with a cooling device and with a motor vehicle according to the features of the independent patent claims. Advantageous configurations are the subject matter of dependent patent claims.

In this respect, according to one aspect, a cooling device for a motor vehicle is provided. The cooling device includes a first circuit and a second circuit. The first circuit has a compressor, a condenser, a first expansion device and an evaporator. The second circuit is thermally coupled to the first circuit via a heat exchanger. The second circuit is also thermally coupled to an energy store. The energy store is preferably an electric battery, typically a traction battery for the electrically operated motor vehicle.

The cooling device also has an ejector pump, which is arranged in the first circuit upstream of the compressor and downstream of the heat exchanger. A particularly efficient operation of the cooling device can be achieved by means of the ejector pump. The ejector pump makes it possible to accelerate the coolant flowing through it and thereby exert a suction effect, for example on the outlet of the evaporator of the cooling device. As a result, the operating pressure in the evaporator can be reduced, which can be accompanied by a temperature reduction in the area of the evaporator. A temperature reduction in the area of the evaporator in turn leads to an improved energy balance and efficient operation of the entire cooling device, in particular for the first circuit, which can typically be designed as a motor vehicle air conditioning system.

Furthermore, by providing the ejector pump upstream of the compressor, a suction pressure provided on the inlet side of the compressor can be increased without the pressure level in the upstream evaporator of the first circuit having to be increased for this purpose. This effect also leads to a reduction in temperature in the area of the evaporator. This again enables the cooling device and the first circuit to operate extremely efficiently.

In particular, it is provided that the first circuit is configured as a refrigerant circuit. A refrigerant typically circulates in the first circuit. In particular, the first circuit can be configured or designed as a refrigerant circuit of a motor vehicle air conditioning system. The second circuit can also be designed as a coolant circuit. It is thermally coupled to the first circuit. A coolant typically circulates in the second circuit in order to cool the energy store.

According to a further embodiment, the ejector pump is arranged downstream of the evaporator in the first circuit. Because the ejector pump is arranged downstream of the evaporator and upstream of the compressor, it can lead to a pressure increase in the first circuit on the compressor side and a pressure reduction in the first circuit on the evaporator side. Both effects have an advantageous effect on the energy efficiency of the operation of the cooling device.

According to a further embodiment of the cooling device, the first circuit has a first refrigerant branch and a second refrigerant branch running parallel thereto. The evaporator is arranged in the first refrigerant branch. The warmth exchanger is located in the second refrigerant branch. The first refrigerant branch and the second refrigerant branch open into the ejector pump. In terms of flow, the ejector pump is located at the downstream end of the first refrigerant branch and the second refrigerant branch. The first refrigerant branch and the second refrigerant branch are reunited via the ejector pump and flow into the inlet of the compressor via the ejector pump.

The ejector pump fulfills a dual function here. On the one hand, it leads to a change in the pressure levels in the area of the evaporator and on the inlet side of the compressor in the first circuit. On the other hand, in terms of device technology, it causes the first and second refrigerant branches to be combined.

According to a further embodiment, in the first coolant branch upstream of the evaporator, i. H. upstream of the evaporator in terms of flow, the first expansion element is arranged. The first expansion element is typically designed as a controllable expansion valve. The flow of the refrigerant through the downstream evaporator can be set or regulated as required by means of the first expansion element.

According to a further embodiment, a second expansion element is arranged in the second refrigerant branch upstream of the heat exchanger. The second expansion element can also be designed as a controllable expansion valve. The flow of refrigerant in the white coolant branch can be adjusted and regulated as required via the second expansion element.

Typically, the first and second expansion devices are independently adjustable and controllable. The first and/or second expansion element is typically controlled via an electronic controller of the cooling device.

According to a further embodiment, the ejector pump has a first inlet, a second inlet, an outlet and a mixing chamber. The first inlet and the second inlet open into the mixing chamber. The outlet, on the other hand, is fed by the mixing chamber. Refrigerant flowing into the mixing chamber via the first inlet and via the second inlet mixes in the mixing chamber and flows from the mixing chamber via the outlet in the direction of the compressor.

According to a further embodiment, the first inlet of the ejector pump is fluidically connected to an outlet of the heat exchanger. This is typically a direct flow connection without the interposition of other components of the cooling device or circuit. A pipe and/or hose line typically runs from the outlet of the heat exchanger into the first inlet of the ejector pump.

According to a further embodiment, the second inlet of the ejector pump is fluidically connected to an outlet of the evaporator. Here, too, it is typically a direct flow connection, which is typically provided by a hose and/or pipeline. A piece of line that is fluidically connected to the outlet of the evaporator is connected to the second inlet of the ejector pump.

According to a further embodiment, the outlet of the ejector pump is fluidically connected to an inlet of the compressor. Here, too, a direct flow connection can be implemented by means of a fluid and/or gas-carrying line.

According to a further embodiment, the suction jet pump has a driving nozzle into which the first inlet of the suction jet pump opens. In other words, the driving nozzle of the ejector pump is fluidically connected to the outlet of the heat exchanger. In this way, the kinetic energy of the refrigerant flowing out of the heat exchanger can be used to accelerate the medium flowing into the ejector pump via the second inlet.

According to a further embodiment, the ejector pump has an intake port which is connected to the second inlet or formed by it. The ejector pump is typically in direct flow connection with the outlet of the evaporator. In this way, a suction can be provided at the outlet of the evaporator, which can lead to a reduction in the pressure in the evaporator. In other words, it is also conceivable and provided in this configuration to use the kinetic energy of the medium flowing out of the heat exchanger in order to accelerate the medium flowing out of the evaporator and overall to increase the inlet-side pressure at the downstream compressor.

In this case, the suction pressure on the inlet side of the compressor can also be increased without increasing the pressure level in the evaporator. This ultimately leads to reducing the temperature at the evaporator, which is beneficial to the Can prove energy efficiency of the operation of the air conditioning system formed by the first circuit.

According to a further embodiment, the energy store, with which the second circuit is thermally coupled, is an electric battery. This can be an electric traction battery, from which electrical energy is provided for driving the motor vehicle.

According to a further embodiment, the first circuit forms a motor vehicle air conditioning system. Due to the thermal coupling of the first circuit and the second circuit, the battery of the motor vehicle can be cooled by means of the motor vehicle air conditioning system as required and in a particularly energy-efficient manner.

The heat exchanger is typically designed as a counterflow heat exchanger. It can also commonly be designed as a so-called chiller.

According to a further embodiment of the cooling device, the second circuit has its own coolant pump. That is, the refrigerant circulating in the second circuit can circulate independently of the refrigerants circulating in the first circuit. The cooling capacity of the second circuit can be adjusted as required, in particular by the second expansion element and by means of the coolant pump.

According to all of the above and according to a further aspect, the present development also relates to a motor vehicle, in particular a passenger car, which has a cooling device as described above. The motor vehicle typically has a drive, such as an internal combustion engine or an electric motor. The motor vehicle can be designed as a purely electric vehicle or as a hybrid vehicle. For the operation of an electric motor, the motor vehicle has an energy store in the form of an electric battery, which is thermally coupled to the second circuit of the cooling device described above. The first circuit, on the other hand, forms an air conditioning system for the motor vehicle, which is used to control the temperature of the motor vehicle interior.

character list

• 1 ein Blockschaltbild der Kühlvorrichtung,
• 2 eine schematische Darstellung eines mit der Kühlvorrichtung ausgestatteten Kraftfahrzeugs und
• 3 eine Prinzipskizze einer in der Kühlvorrichtung vorgesehenen Saugstrahlpumpe.

Further goals, features and advantageous refinements of the present development are explained in the following description of an exemplary embodiment. Here show:

• 1 a block diagram of the cooling device,
• 2 a schematic representation of a motor vehicle equipped with the cooling device and
• 3 a schematic diagram of a suction jet pump provided in the cooling device.

Detailed description

This in 2 Motor vehicle 1 shown has a motor vehicle body 2 with an interior 3 functioning as a passenger cell. The motor vehicle 1 is also equipped with a drive 4, typically an electric motor. The drive 4 can be supplied with electrical energy by means of an energy store 40 . The energy store 40 can be designed as an electric and chargeable battery 41 .

The motor vehicle 1 also has a cooling device 10. The in 1 The cooling device 10 shown schematically in a block diagram has a first circuit 11 and a second circuit 21 . The first circuit 11 and the second circuit 21 are thermally coupled to one another via a heat exchanger 20, also commonly referred to as a chiller. The first circuit 11 functions as a motor vehicle air conditioning system 5. It has a compressor 12, a condenser 13, a first expansion element 14 and an evaporator 15, which are fluidically connected to one another in this order in the first circuit 11 via a refrigerant line 6.

An outlet of the compressor 12 is fluidly coupled to an inlet of the condenser 13 . An outlet of the condenser 13 is coupled to an inlet of the first expansion device 14 . An outlet of the first expansion device 14 is coupled to the evaporator 15 . The outlet of the evaporator 15 is in turn coupled to an inlet of the compressor 12 . The refrigerant circulating in circuit 11 can be compressed by means of the compressor.

In the condenser 13, thermal energy of the refrigerant is released to the environment. The refrigerant is expanded by means of the first expansion element 14 , as a result of which the refrigerant cools down and can finally again absorb thermal energy from the environment in the region of the evaporator 15 . A compensating tank 26 for receiving and discharging refrigerant can be provided on the condenser.

A suction jet pump 30 is arranged in the first circuit 11 upstream of the compressor 12 and downstream of the heat exchanger 20 or downstream of the evaporator 15 . A suction pressure can be increased at the inlet 19 of the compressor 12 by means of the ejector pump 30 without here having to raise the pressure level in the evaporator 15. As a result, the temperature in the area of the evaporator can be reduced, which can have an advantageous effect on the efficiency and the energy consumption for operating the first circuit 11 .

By means of the ejector pump 30, however, a suction effect can also be provided at the outlet 17 of the evaporator 15, which can likewise be accompanied by a temperature reduction in the area of the evaporator 15 and with a corresponding increase in efficiency.

As in particular in 1 shown, the first circuit 11 has a first refrigerant branch 16 and a second refrigerant branch 18 running parallel thereto. The first and second refrigerant branches 16, 18 branch out from the common refrigerant line 6 downstream of the condenser 13. The first refrigerant branch 16 has the first expansion element 14, which is located upstream of the evaporator 15. The second refrigerant branch 18 has a second expansion element 24 which is upstream of the heat exchanger 20 in terms of flow.

An outlet 17 of the evaporator 15 opens into a second inlet 32 of the suction jet pump 30. An outlet 23 of the heat exchanger 20 opens into a first inlet 31 of the suction jet pump. The ejector pump 30 has only a single outlet 33 which is in direct flow communication with the inlet 19 of the compressor 12 .

The second circuit 21 has a further coolant line 8 which energetically or thermally couples a coolant pump 28 and a battery heat exchanger 42 provided in the area of an energy store 40 to the heat exchanger 20 . The heat exchanger 20 can be designed as a counterflow heat exchanger. The flow direction of the coolant flowing through the coolant line 8 is opposite to the flow direction of the coolant flowing through the coolant line 6 .

The battery heat exchanger 42 is in thermal contact with the energy store 40 and therefore with the battery 41 .

From the synopsis of 1 and 3 shows the internal structure of the ejector pump 30 and its connections, or its fluidic coupling with the other components of the cooling device 10 in more detail. The ejector pump 30 has a first inlet 31 and a second inlet 32 as well as a driving nozzle 36 and a suction nozzle 34 . The motive nozzle 36 is connected to the first inlet 31 . In other words, the first inlet 31 opens into the propulsion nozzle 36. The suction nozzle 34 forms the second inlet 32 or is fed by it. Furthermore, the ejector pump 30 has a mixing chamber 35, in which the first inlet 31 and the second inlet, and thus the suction nozzle 34 and the propulsion nozzle 36, open. The outlet 33 of the ejector pump 30 is fed by the mixing chamber 35 . The refrigerant mixed in the mixing chamber 35 flows from the mixing chamber 35 through the outlet 33 to the compressor 12.

In the embodiment shown here, it is provided that the refrigerant flowing from the heat exchanger 20 flows into the mixing chamber 35 via the first inlet 31 and thus via the driving nozzle 36 . The kinetic energy of the refrigerant provided by the heat exchanger 20 leads to a suction effect in the area of the second inlet 32, and therefore in the area of the suction connection 34. The suction connection 34 or the second inlet 32 is in flow communication with the outlet 17 of the evaporator 15. In this way and Way, a suction effect can be provided on the outlet side at the evaporator 15, which can lead to the temperature reduction already mentioned and thus to the efficiency increase of the air conditioning system 5.

The illustrated embodiments only show possible configurations of the development, for which numerous further variants are conceivable within the scope of the development. The exemplary embodiments shown are in no way to be interpreted as limiting with regard to the scope, the applicability or the configuration possibilities of the development. The present description indicates only one or a few possible implementation(s) of an exemplary embodiment to those skilled in the art. A wide variety of modifications can be made to the function and arrangement of the elements described without departing from the scope of protection defined by the following claims or its equivalents.

Reference List

1

motor vehicle

2

automobile body

3

inner space

4

drive

5

automotive air conditioning

6

refrigerant line

8th

coolant line

10

cooler

11

cycle

12

come professor

13

capacitor

14

expansion organ

15

Evaporator

16

refrigerant branch

17

outlet

18

refrigerant branch

19

inlet

20

heat exchanger

21

cycle

23

outlet

24

expansion organ

26

expansion tank

28

coolant pump

30

ejector pump

31

inlet

32

inlet

33

outlet

34

Sausage

36

driving nozzle

40

energy storage

41

battery

42

battery heat exchanger

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• EP 3010750 B1 [0002]
• FR 3077242 B1 [0003]

Claims (15)

Cooling device (10) for a motor vehicle (1) comprising: - a first circuit (11) which has a compressor (12), a condenser (13), a first expansion element (14) and an evaporator (15), - a second circuit (21), which is thermally coupled to an energy store (40) and via a heat exchanger (20) to the first circuit (11), - An ejector pump (30) which is arranged in the first circuit (11) upstream of the compressor (12) and downstream of the heat exchanger (20). Cooling device (10) after claim 1 , wherein the ejector pump (30) is arranged downstream of the evaporator (15) in the first circuit (11). Cooling device (10) after claim 1 or 2 , wherein the first circuit (11) has a first refrigerant branch (16) and a second refrigerant branch (18) running parallel thereto, the evaporator (15) being arranged in the first refrigerant branch (16), the heat exchanger (20) in the second refrigerant branch (18) is arranged and wherein the first refrigerant branch (16) and the second refrigerant branch (18) open into the ejector pump (30). Cooling device (10) after claim 3 , wherein the first expansion element (14) is arranged in the first refrigerant branch (16) upstream of the evaporator (15). Cooling device (10) after claim 3 or 4 , A second expansion element (24) being arranged in the second refrigerant branch (18) upstream of the heat exchanger (20). Cooling device (10) according to one of the preceding claims, wherein the ejector pump (30) has a first inlet (31), a second inlet (32), an outlet (33) and a mixing chamber (35), the first inlet (31) and the second inlet (32) opens into the mixing chamber (35) and the outlet (33) is fed from the mixing chamber (35). Cooling device (10) after claim 6 , wherein the first inlet (31) is fluidly connected to an outlet (23) of the heat exchanger (20). Cooling device (10) after claim 6 or 7 , wherein the second inlet (32) of the ejector pump (30) is fluidically connected to an outlet (17) of the evaporator (15). Cooling device (10) according to any one of the preceding Claims 6 until 8th , wherein the outlet (33) of the ejector pump (30) is fluidically connected to an inlet (19) of the compressor (11). Cooling device (10) according to any one of the preceding Claims 6 until 9 , wherein the ejector pump (30) has a driving nozzle (36) into which the first inlet (31) opens. Cooling device (10) according to any one of the preceding Claims 6 until 10 , The ejector pump (30) having a suction port (34) which is connected to the second inlet (32) or formed therefrom. Cooling device (10) according to one of the preceding claims, wherein the energy store (40) has an electric battery (41). Cooling device (10) according to one of the preceding claims, wherein the first circuit (11) forms a motor vehicle air conditioning system (5). Cooling device (10) according to one of the preceding claims, wherein the second circuit (21) has a coolant pump (28). Motor vehicle (1) with a cooling device (10) according to one of the preceding claims.

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