DE102019120332A1 - Cooling system - Google Patents

Abstract

Cooling system (1) with a first cooling circuit (2) and a second cooling circuit (3) through which a fluid (4) can flow; wherein the first cooling circuit (2) can be fluidically connected to an expansion tank (8) via a first filling line (5) and at least one first vent line (6, 7), the second cooling circuit (3) only being connected via a second vent line (9) can be fluidically connected to the expansion tank (8).

Description

The invention relates to a cooling system with a first cooling circuit and a second cooling circuit through which a fluid (a coolant, for example water or water with additives) can flow. The cooling system is intended in particular for temperature control of components of a motor vehicle.

Motor vehicles have one or more cooling systems in which a coolant is pumped into (each) a cooling circuit by one or more pumps. Thermal energy from components integrated in the respective cooling circuit, in particular the internal combustion engine and, for example, an oil cooler and / or a charge air cooler, is absorbed via the fluid. This thermal energy is then released into the ambient air via an ambient heat exchanger (a cooler).

Several cooling circuits can be provided in a motor vehicle. It is known to have a high-temperature cooling circuit which is provided for cooling the drive motor (e.g. an internal combustion engine or an electric drive unit) and other components and whose operating temperature during normal operation of the motor vehicle can be higher than 90 ° C [degrees Celsius], as well as a low-temperature cooling circuit whose operating temperature should not exceed 90 ° C in normal operation.

For a good and, in particular, efficient cooling performance of a cooling circuit, it is relevant that this is as completely vented as possible. Accordingly, on the one hand, the air contained in the cooling circuit, which is displaced by the inflowing coolant, must be discharged as completely as possible during the filling process of the cooling circuit, in particular during an initial filling or a new filling as part of maintenance. In addition, when the motor vehicle and thus the cooling circuit are in operation, gas can be produced by evaporation processes that should be safely discharged. Controlled boiling can increase the heat flux density and therefore such type of boiling cooling circuit design is allowed. The resulting vapor bubbles should be removed accordingly.

A cooling circuit is regularly vented via an expansion tank in the cooling system. Such an expansion tank also has the task of compensating for the different thermal expansion of the coolant and is partially filled with air for this purpose. For ventilation, a ventilation line can lead from the highest point of the respective cooling circuit of a cooling system to the (shared) expansion tank, which is arranged even higher.

In cooling systems in which a high-temperature and a low-temperature cooling circuit are connected to the same expansion tank, a vent line arranged in this way can lead to an overflow of coolant from the expansion tank into the low-temperature cooling circuit. This is to be avoided in particular in full load operation of a drive motor of the motor vehicle with a correspondingly high temperature in the high-temperature cooling circuit and the expansion tank in order not to exceed the limit temperature in the low-temperature cooling circuit. It can therefore be provided to avoid an overflow of coolant from the expansion tank into the low-temperature cooling circuit by integrating a check valve in the vent line. However, such a check valve can make it more difficult to fill the low-temperature cooling circuit because a pressure level required to open the check valve must be built up for venting. In such a cooling circuit, static filling, which, in contrast to dynamic filling, takes place without the support of the pump of the corresponding cooling circuit, is only possible to a limited extent.

From the DE 10 2013 226 420 A1 a vent valve for a cooling circuit of an internal combustion engine is known. The vent valve is switched via the liquid coolant.

From the DE 10 2015 111 407 A1 a cooling system with a high-temperature cooling circuit and a low-temperature cooling circuit is known. Both cooling circuits are connected to a jointly used expansion tank. The low-temperature circuit can only be vented in certain operating states.

From the DE 20 2016 005 768 U1 a cooling device for a motor vehicle is known, a valve device for temperature-dependent interconnection of a high-temperature cooling circuit with a low-temperature cooling circuit being proposed.

From the DE 10 2013 221 447 A1 A cooling system for a motor vehicle is known in which a low-temperature cooling circuit and a high-temperature cooling circuit are connected to a jointly used expansion tank. The low-temperature circuit is only connected to the expansion tank via a filling line.

The object of the present invention is to at least partially solve the problems cited with reference to the prior art. In particular, a cooling system is to be specified which is constructed as simply as possible, with an overflow of coolant from one cooling circuit into the other cooling circuit being excluded as far as possible.

A cooling system with the features according to claim 1 contributes to achieving these objects. Advantageous further developments are the subject of the dependent claims. The features listed individually in the patent claims can be combined with one another in a technologically meaningful way and can be supplemented by explanatory facts from the description and / or details from the figures, with further design variants of the invention being shown.

A cooling system or a cooling arrangement is proposed with a first cooling circuit and a second cooling circuit through which a fluid can flow. The first cooling circuit can be fluidically connected or connected to an expansion tank via a first filling line and at least one first vent line, the second cooling circuit being fluidically connectable or connected to the expansion tank only via a second vent line (directly).

The second cooling circuit therefore does not have its own or separate or separate filling line. The second cooling circuit is fluidically connected or connectable to the expansion tank exclusively via the second vent line and is coupled via this to the first cooling circuit (that is, fluidically connected or connectable).

The two cooling circuits include in particular a high-temperature cooling circuit and a low-temperature cooling circuit as described above. The first cooling circuit is in particular a high-temperature cooling circuit. The second cooling circuit is in particular a low-temperature cooling circuit.

In a high-temperature circuit, in particular one or more of the following components are arranged, which can be temperature-controlled via the fluid: cylinder head (first component), internal exhaust manifold (second component), cylinder crankcase (third component; components of an internal combustion engine in each case), heating system heat exchanger (fourth component) for heating the interior of the motor vehicle, engine oil cooler (fifth component). In this case, the fluid is cooled again via a high-temperature circuit cooler which is arranged in the high-temperature circuit and over which ambient air in particular flows.

In a low-temperature cooling circuit, in particular one or more of the following components are arranged, which can be tempered by the fluid: charge air cooler (sixth component), exhaust gas turbocharger heat exchanger (seventh component). In this case, the fluid is cooled down again via a low-temperature circuit cooler which is arranged in the low-temperature circuit and over which ambient air flows in particular.

In particular, the pumps and coolers arranged in the cooling circuits are also considered components of the cooling circuit. In particular, the ventilation lines are not referred to as components of the cooling circuit, but only referred to as components of the cooling system.

The second cooling circuit is in particular a low-temperature cooling circuit, so that it can be designed for an operating temperature of the fluid of a maximum of approx. 90 ° C. In such a cooling circuit, venting is essentially only necessary while the cooling system is being filled with the fluid, since, due to the relatively low operating temperature, no evaporation of fluid (e.g. water, possibly with additives) should take place to a relevant extent and thus after If filling and venting have already taken place, only correspondingly small amounts of air or gas are produced by local boiling.

In particular, both cooling circuits are connected to the same expansion tank. The problem of an overflow of comparatively hot fluid from the high-temperature cooling circuit via the vent line of the low-temperature cooling circuit into the low-temperature cooling circuit, which is known from corresponding cooling systems of the generic type and which is sometimes elaborately avoided by a non-return valve in the prior art, can be avoided because a separate filling line is not required for the second Cooling cycle does not occur.

It is known that both cooling circuits (high-temperature and low-temperature cooling circuit) are connected to the same expansion tank not only via the respective vent line but also via the respective filling line. The filling line is regularly connected to a suction side of the respective main cooling circuit pump. Hot fluid flows from the high-temperature cooling circuit into the expansion tank and is sucked in through the low-temperature cooling circuit under certain operating conditions. This can lead to an increase in the temperature level in the low-temperature cooling circuit. In the case of heavy pump operation in the high-temperature cooling circuit, the pressure level in the low-temperature cooling circuit can drop so far that pump cavitation or boiling can occur in the low-temperature cooling circuit. The proposed omission of the filling line in the second cooling circuit (especially in the Low-temperature cooling circuit) the mentioned pressure reduction and temperature increase do not occur in this (low-temperature) cooling circuit.

In particular, the first cooling circuit has a first pump for conveying a fluid through the first cooling circuit and thus a first high-pressure side present downstream of the first pump and a first low-pressure side present upstream of the first pump. The at least one first vent line is arranged on the first high pressure side and the second vent line is coupled (fluidically connected) to the at least one first vent line.

The coupling of the second vent line to the at least one first vent line is in particular upstream of the bleaching tank, that is, in a feed line of the vent lines to the expansion tank.

In particular, the at least one first vent line and the second vent line are directly connected to the high pressure side of the first cooling circuit.

“Immediately” here means in particular that starting from the high pressure side and in the at least one first vent line connected to the high pressure side and in the second vent line no pressure reduction is undertaken, e.g. B. via a throttle.

A pressure reduction, in particular in the first vent line, through which an overflow of fluid into the second cooling circuit is otherwise to be avoided, is not necessary here due to the lack of a second filling line. In this way, however, the pressure level in the second cooling circuit can be increased, so that the high pressures then applied also cause the fluid (e.g. water) to boil in the second cooling circuit on the components (e.g. heat exchangers for exhaust gas turbochargers) in the second cooling circuit and / or charge air cooler) can be avoided.

In particular, the second cooling circuit is connected to the expansion tank via the second vent line without a non-return valve (or "non-return valve" or "free from non-return valves").

The check valve, which is otherwise provided to prevent hot fluid from flowing over, can thus be saved.

In particular, the first cooling circuit is connected to the expansion tank via the at least one first vent line without a non-return valve (or “without non-return valves” or “without non-return valves”).

In particular, the first cooling circuit has a plurality of partial cooling circuits to which fluid is applied via the first pump. At least two of the partial cooling circuits each have a first vent line. At least one of these plurality of first ventilation lines is connected to the expansion tank without a check valve.

In particular, the second cooling circuit has a second pump for conveying a fluid through the second cooling circuit and thus a second high-pressure side present downstream of the second pump and a second low-pressure side present upstream of the second pump. In particular, the second vent line is arranged on the second high pressure side.

In particular, a cooling circuit has a cooler, on which in particular the fluid circulating in the cooling circuit is cooled by the ambient air flowing over the cooler. A high pressure side of a cooling circuit is arranged in particular downstream of the pump and upstream of the cooler. Accordingly, a low-pressure side is arranged downstream of the cooler and upstream of the pump.

In particular, the second vent line is double-flow with a first flow channel and a second flow channel, the first flow channel being provided for venting the second cooling circuit and the second flow channel being provided for filling the second cooling circuit with the fluid.

1. a) Befüllen des ersten Kühlkreislaufs (z. B. über die erste Befüllleitung);
2. b) Befüllen des zweiten Kühlkreislaufs über die zumindest eine erste Entlüftungsleitung und die damit verbundene zweite Entlüftungsleitung.

A method for filling the cooling system described is proposed. The method comprises at least the following steps:

1. a) Filling the first cooling circuit (e.g. via the first filling line);
2. b) Filling the second cooling circuit via the at least one first vent line and the second vent line connected to it.

In particular, the cooling circuits are vented before filling, e.g. B. via suction of air (evacuation).

In particular, the cooling circuits are filled via a filling opening on the expansion tank.

In particular, the cooling circuits are vented via an opening (possibly the filling opening) on the expansion tank.

In particular, step a) of the method takes place after the venting. The first cooling circuit is filled in particular until the fluid reaches the coupling point to the second vent line. This coupling point is in particular, with regard to gravity and a proper position of the cooling system (e.g. horizontal position of a motor vehicle), below the expansion tank and above the cooling circuits and / or preferably above all components of the cooling circuits. The fluid can flow into the second cooling circuit along the second vent line via the coupling point.

The filling takes place in particular under negative pressure, that is, after the air in the cooling system has been sucked off.

In particular, gas or air can also be discharged passively (without operating the second pump) from the second cooling circuit via the second ventilation line. In particular, gas or air can also be removed by operating the second pump, that is to say during or immediately after step b).

In particular, the first cooling circuit is connected to the expansion tank via the at least one first vent line without a non-return valve, so that at least the first cooling circuit is permanently vented into the expansion tank.

Permanent venting means in particular that the gas or air in the cooling circuit is not accumulated but can flow off continuously via a vent line to the expansion tank. Check valves work with the pressure difference upstream and downstream of the valve and can prevent flow in the line until a pressure level is reached at which the check valve opens. An open check valve creates additional pressure loss in the line and reduces the flow rate.

In particular, the second cooling circuit is connected to the expansion tank via the second vent line without a check valve, so that at least the second cooling circuit is permanently vented into the expansion tank.

In particular, the filling can also be carried out without prior ventilation. In particular, the first cooling circuit should first be filled via the expansion tank, the first pump then being actuated. Only through the operation of the first pump can fluid also be conveyed into the second cooling circuit via the second vent line. After the second cooling circuit has been filled, the second pump can be put into operation, so that the venting of the second cooling circuit is at least supported via the second venting line.

The statements on the cooling system can in particular be transferred to the method and vice versa.

As a precaution, it should be noted that the numerals used here (“first”, “second”, ...) primarily (only) serve to distinguish between several similar objects, sizes or processes, so in particular no dependency and / or sequence of these objects, sizes or prescribe processes to each other. Should a dependency and / or sequence be required, this is explicitly stated here or it is obvious to the person skilled in the art when studying the specifically described embodiment. If a component can occur several times (“at least one”), the description of one of these components can apply equally to all or part of the majority of these components, but this is not mandatory.

• 1: ein bekanntes Kühlsystem;
• 2: eine erste Ausführungsvariante eines Kühlsystems; und
• 3: eine zweite Ausführungsvariante eines Kühlsystems.

The invention and the technical environment are explained in more detail below with reference to the accompanying figures. It should be pointed out that the invention is not intended to be restricted by the exemplary embodiments cited. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description. In particular, it should be pointed out that the figures and in particular the size relationships shown are only schematic. Show it:

• 1 : a known cooling system;
• 2 : a first variant embodiment of a cooling system; and
• 3 : a second variant of a cooling system.

The 1 shows a known cooling system 1 , with a first cooling circuit 2 and a second cooling circuit 3 that of a fluid 4th are permeable. The first cooling circuit 2 is via a first filling line 5 and a plurality of first vent lines 6 , 7th with an expansion tank 8th fluidly connectable or connected, the second cooling circuit 3 via a second vent line 9 and a second filling line 29 with the expansion tank 8th is fluidly connectable or connected. It can be seen in each of the first ventilation lines 6 , 7th and in the second vent line 9 one check valve each 13 arranged. A first vent line 6 is via a throttle arranged in the first vent line 30th with the second vent line 9 coupled.

The rest of the structure of the cooling system 1 is related to 2 and 3 explained below.

2 shows a first embodiment of a cooling system 1 . The cooling system 1 comprises a first cooling circuit 2 and a second cooling circuit 3 that of a fluid 4th are permeable. The first cooling circuit 2 is via a first filling line 5 and at least one first vent line 6 , 7th with an expansion tank 8th fluidly connectable or connected, the second cooling circuit 3 only via a second ventilation line 9 with the expansion tank 8th is fluidly connectable or connected.

The first cooling circuit 2 is a high temperature cooling circuit. The second cooling circuit 3 is a low temperature cooling circuit.

In the high temperature cycle are the following components 10 , 20th , 22nd , 23 , 24 , 25th , 26th arranged over the fluid 4th temperature controlled: cylinder head (first component 22nd ), internal exhaust manifold (second component 23 ), Cylinder crankcase (third component 24 ; Components 22nd , 23 , 24 are components of an internal combustion engine), heating heat exchangers (fourth component 25th ) for heating the interior of the vehicle, engine oil cooler (fifth component 26th ). This is where the fluid 4th via a first cooler arranged in the high-temperature circuit 20th , over which the ambient air flows, is cooled down again. The fluid 4th is about the first pump 10 promoted.

In the low temperature refrigeration cycle, there are the following components 21st , 27 , 28 arranged over the fluid 4th Can be temperature controlled: intercooler (sixth component 27 ), Exhaust gas turbocharger heat exchanger (seventh component 28 ). This is where the fluid 4th Via a second cooler arranged in the low-temperature circuit 21st , over which the ambient air flows, is cooled down again. The fluid 4th is about the second pump 14th promoted.

Both cooling circuits 2 , 3 are with the same expansion tank 8th connected. The corresponding generic cooling systems 1 known problem of an overflow of comparatively hot fluid 4th from the high-temperature cooling circuit via the (second) ventilation line 9 of the low-temperature cooling circuit in the low-temperature cooling circuit, which in the prior art is sometimes complex by a check valve 13 is avoided (see 1 ), due to the fact that a separate (second) filling line can be dispensed with 29 for the second cooling circuit 3 do not occur.

The first cooling circuit 2 has a first pump 10 for conveying a fluid 4th through the first cooling circuit 2 and thus one downstream of the first pump 10 present first high pressure page 11 and one upstream of the first pump 10 present first low pressure side 12th on. The first ventilation lines 6 , 7th are on the first high pressure side 11 arranged and the second vent line 9 is with the first vent lines 6 , 7th coupled (fluidly connected).

The coupling of the second vent line 9 with the first vent lines 6 is upstream of the bleaching tank 8th , so in a feed line of the ventilation lines 6 , 7th , 9 towards the expansion tank 8th .

The first vent line 6 and the second vent line 9 are directly with the first high pressure side 11 of the first cooling circuit 2 connected, ie that starting from the first high pressure side 11 and in the one on the first high pressure side 11 connected a first vent line 6 and in the second vent line 9 no pressure reduction is made, e.g. B. via a throttle 30th (please refer 1 ).

A pressure reduction in the first vent line 6 through which an overflow of fluid 4th in the second cooling circuit 3 otherwise it should be avoided is due to the lack of a second filling line 29 not mandatory. However, this can reduce the pressure level in the second cooling circuit 3 are raised, so that the high pressures then also in the second cooling circuit 3 a boiling of the fluid 4th to those in the second cooling circuit 3 arranged components 27 , 28 can be avoided.

The second cooling circuit 3 is via the second vent line 9 without a check valve 13 (ie “no check valve” or “free from check valves 13”) with the expansion tank 8th connected.

Otherwise to avoid an overflow of hot fluid 4th provided check valve 13 (please refer 1 ) can thus be saved.

The first cooling circuit 2 is via the first vent line 7th without a check valve 13 with the expansion tank 8th connected.

The first cooling circuit 2 has several partial cooling circuits that are via the first pump 10 with fluid 4th are applied. The first component is in a partial cooling circuit 22nd and the second component 23 , the third component in another partial cooling circuit 24 , the fourth component in a further partial cooling circuit 25th and the fifth component in an additional partial cooling circuit 26th arranged. At least two partial cooling circuits each have a first vent line 6 , 7th on. A first vent line 7th of the first cooling circuit 2 is without a check valve 13 with the expansion tank 8th connected. The other first vent line 6 is immediately upstream of the first cooler 20th to the first cooling circuit 2 connected and with a check valve 13 fitted.

About the no check valve 13 having vent lines 7th , 9 can the respective cooling circuit 2 , 3 permanently in the expansion tank 8th be vented.

The second cooling circuit 3 includes a second pump 14th for conveying a fluid 4th through the second cooling circuit 3 and thus has a downstream of the second pump 14th present second high pressure side 15th and one upstream of the second pump 14th present second low pressure side 16 on. The second vent line 9 is on the second high pressure side 15th arranged.

According to step a) of the method for filling the cooling system described 1 the first cooling circuit is filled 2 via the first filling line 5 and then, according to step b), filling the second cooling circuit 3 via the at least one first vent line 6 , 7th and the associated second vent line 9 .

The cooling circuit can be vented before filling 2 , 3 take place, e.g. B. via suction of air (evacuation).

The first cooling circuit 2 is filled until the fluid 4th the coupling point to the second vent line 9 reached. This coupling point includes a vent port 19th and lies below the expansion tank 8th and above the cooling circuits 2 , 3 and / or preferably above all components 1 , 14th , 20th , 21st , 22nd , 23 , 24 , 25th , 26th , 27 , 28 the cooling circuits 2 , 3 . The fluid can 4th along the second vent line 9 in the second cooling circuit 3 pour in.

The vent ports (at the ends of the second vent line 9 ) are each shown in an enlarged view.

3 shows a second variant embodiment of a cooling system 1 . On the remarks too 2 is referred.

The difference to the first variant is the second vent line 9 double flow with a first flow channel 17th and a second flow channel 18th formed, the first flow channel 17th for venting the second cooling circuit 3 and the second flow channel 18th for filling the second cooling circuit 3 with the fluid 4th is provided. The ventilation ports provided for this 19th are each shown in an enlarged view.

It is advantageous with the cooling system proposed here 1 the vent ports 19th adapt. In particular, those for the fluid 4th flowable cross-sections are enlarged.

List of reference symbols

1

Cooling system

2

first cooling circuit

3

second cooling circuit

4th

Fluid

5

first filling line

6th

first vent line

7th

further first vent line

8th

Expansion tank

9

second vent line

10

first pump

11

first high pressure side

12

first low pressure side

13

check valve

14th

second pump

15th

second high pressure side

16

second low pressure side

17th

first flow channel

18th

second flow channel

19th

Vent port

20th

first cooler

21st

second cooler

22nd

first component

23

second component

24

third component

25th

fourth component

26th

fifth component

27

sixth component

28

seventh component

29

second filling line

30th

throttle

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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

• DE 102013226420 A1 [0007]
• DE 102015111407 A1 [0008]
• DE 202016005768 U1 [0009]
• DE 102013221447 A1 [0010]

Claims (10)

Cooling system (1) with a first cooling circuit (2) and a second cooling circuit (3) through which a fluid (4) can flow; wherein the first cooling circuit (2) can be fluidically connected to an expansion tank (8) via a first filling line (5) and at least one first vent line (6, 7), the second cooling circuit (3) only being connected via a second vent line (9) can be fluidically connected to the expansion tank (8). Cooling system (1) Claim 1 , the first cooling circuit (2) having a first pump (10) for conveying the fluid (4) through the first cooling circuit (2) and thus a first high-pressure side (11) downstream of the first pump (10) and one upstream of the first pump (10) has present first low-pressure side (12); wherein the at least one first vent line (6, 7) is arranged on the first high pressure side (11) and wherein the second vent line (9) is coupled to the at least one first vent line (6, 7). Cooling system (1) Claim 2 wherein the at least one first vent line (6, 7) and the second vent line (9) are directly connected to the first high pressure side (11) of the first cooling circuit (2). Cooling system (1) according to one of the preceding claims, wherein the second cooling circuit (3) is connected to the expansion tank (8) via the second vent line (9) without a check valve (13). Cooling system (1) according to one of the preceding claims, wherein the first cooling circuit (2) is connected to the expansion tank (8) via the at least one first vent line (6) without a check valve (13). Cooling system (1) according to one of the preceding claims, wherein the second cooling circuit (3) has a second pump (14) for conveying the fluid (4) through the second cooling circuit (3) and thus a second high-pressure side downstream of the second pump (14) (15) and a second low-pressure side (16) present upstream of the second pump (14); wherein the second vent line (9) is arranged on the second high pressure side (15). Cooling system (1) according to one of the preceding claims, wherein the second vent line (9) is designed with a double flow channel (17) and a second flow channel (18), the first flow channel (17) for venting the second cooling circuit (3) and the second flow channel (18) is provided for filling the second cooling circuit (3) with the fluid (4). Method for filling a cooling system (1) according to one of the preceding claims, the method comprising at least the following steps: c) filling the first cooling circuit (2); d) Filling the second cooling circuit (3) via the at least one first ventilation line (6, 7) and the second ventilation line (9) connected to it. Procedure according to Claim 8 , wherein the first cooling circuit (2) is connected to the expansion tank (8) via the at least one first vent line (6, 7) without a check valve (13), so that at least the first cooling circuit (2) is permanently in the expansion tank (8) is vented. Method according to one of the preceding claims, wherein the second cooling circuit (3) is connected to the expansion tank (8) via the second vent line (9) without a check valve (13), so that at least the second cooling circuit (3) is permanently in the expansion tank ( 8) is vented.

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