EP3527800B1 - Cooling system for a propulsion unit of a vehicle - Google Patents

Description

The invention relates to a cooling circuit for a drive unit of a motor vehicle.

From the EP 0 861 368 B1 a cooling circuit with a coolant cooler and a low-temperature coolant cooler is known. To regulate the cooling capacity of the cooling circuit, a valve is provided through which several coolant flows can be interconnected differently.

Such coolers form on the one hand channels through which a fluid to be cooled can flow and which are provided with ribs to improve the heat transfer. On the other hand, the channels or the ribs are flowed over by a gas (e.g. air, airflow), so that the fluid circulating in a cooling circuit can be cooled.

There is a constant need to make the cooling circuits in motor vehicles as simple and compact as possible, whereby the most flexible interconnection of fluid flows for setting the temperature of a fluid flow as a function of an operating point of the motor vehicle or a drive unit is to be made possible.

From the DE 2314301 A1 a cooler with a bypass line is known which is regulated by a thermostat. The thermostat has a vent line on the housing.

From the U.S. 4,144,849 A a cooler with a bypass line is also known, which is controlled by a thermostat. The cooler has a vent line.

From the U.S. 4,679,530 A a cooling system with a cooler and a bypass line is known, the bypass line being controllable via a thermostat. The cooler can be flown through from bottom to top.

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 circuit is to be proposed which has a compact design and enables different interconnection of fluid flows.

A cooling circuit with the features according to patent claim 1 contributes to the solution of these objects. Advantageous further developments are the subject of the dependent claims. The combinations of features of the patent claims can be supplemented by explanatory facts from the description and / or details from the figures, further embodiment variants of the invention being shown.

A cooling circuit of a drive unit of a motor vehicle is proposed. The drive unit is in particular at least one internal combustion engine and / or at least one electrical machine. The drive unit is preferably provided for driving the motor vehicle.

The cooling circuit has at least one first fluid circuit, which is connected to a first cooler for passing a first fluid through the first cooler via a first inlet connection and a first outlet connection. The first inlet connection and the first outlet connection are (in addition or in terms of flow technology also in parallel) via a Bypass line can be connected to one another. The first fluid can be diverted from the first inlet connection to the first outlet connection by bypassing the first cooler via a bypass valve in the bypass line. The bypass valve has at least or precisely one vent connection for venting at least the bypass line.

The first fluid circuit is in particular a low-temperature circuit.

With the bypass valve, the first fluid can be diverted from the first inlet connection to the second outlet connection, bypassing the first cooler. The bypass valve can be controlled and operated in particular via a control device, but is preferably designed to be self-regulating. If the bypass valve is switched in such a way that the first cooler is bypassed, the first fluid can reach a specified minimum temperature more quickly (e.g. after a cold start of the drive unit). If the minimum temperature is reached, the bypass valve can be switched so that the first fluid is passed through the first cooler and is thereby cooled.

The vent connection is provided in particular on the bypass valve, that is to say for example in a line connection piece and / or in / on a housing of the bypass valve. In particular, a flow distance for the first fluid from the bypass valve to the vent connection is not greater than 15 centimeters, possibly even a maximum of 8 centimeters.

In particular, the bypass valve is arranged (directly or in the immediate vicinity) downstream of the first cooler. The bypass valve is preferably arranged on or fastened to the first cooler. Based on the heat exchanger structure (e.g. from air or The bypass valve is in particular arranged at most 20 centimeters away from the airflow channels over which the first fluid flows) of the first cooler.

According to the invention, the first inlet connection and the first outlet connection are arranged so that the first fluid can flow through the first cooler from bottom to top (when installed in the motor vehicle, when the motor vehicle is arranged on a horizontal plane, relative to gravity). This flow through the first cooler from bottom to top has enabled a surprising improvement in the cooling performance. In particular, no or at least less air can accumulate in the first cooler, which air is now also discharged more quickly from the first cooler as a result of the flow from bottom to top. Air in the cooler can reduce the heat transfer in the cooler, at least in comparison with water as the first fluid, so that the cooling performance would be reduced.

The bypass valve can be arranged on the first cooler via at least one plug connection.

In particular, venting of the first cooler can additionally be made possible via the at least or precisely one vent connection.

In particular, the bypass valve has a housing

• einem Auslassanschluss zur Weiterleitung des ersten Fluids (z. B. hin zu einem dritten Kühler; wobei also der dritte Kühler stromabwärts des Auslassanschlusses angeordnet ist),
• einem ersten Anschluss zur Verbindung des Bypass-Ventils mit dem ersten Kühler (wobei der erste Kühler stromaufwärts des ersten Anschlusses angeordnet ist) und
• einem zweiten Anschluss zur Verbindung des Bypass-Ventils mit dem ersten Zulaufanschluss (wobei der erste Zulaufanschluss stromaufwärts des zweiten Anschlusses angeordnet ist)

auf. Das Gehäuse bildet bevorzugt zusätzlich den mindestens oder genau einen (separaten) Entlüftungsanschluss aus.

• an outlet connection for forwarding the first fluid (e.g. to a third cooler; the third cooler is thus arranged downstream of the outlet connection),
• a first connection for connecting the bypass valve to the first cooler (wherein the first cooler is arranged upstream of the first connection) and
• a second connection for connecting the bypass valve to the first inlet connection (the first inlet connection being arranged upstream of the second connection)

on. The housing preferably also forms the at least or precisely one (separate) vent connection.

The first fluid thus enters the housing of the bypass valve in particular either via the first connection (starting from the first cooler) or the second connection (bypassing the first cooler). The first fluid leaves the housing via the outlet connection.

In particular, the vent connection is connected to an expansion tank, so that gas or air contained in the first fluid or in the first fluid circuit can be transferred to the expansion tank via the vent connection.

The first cooler is connected to the bypass valve via a first drain line, the first drain line (e.g. starting from the heat exchanger structure) leading to the bypass valve, e.g. B. towards the first connection, and at least one vent connection rising (in the installed state in the motor vehicle, when the motor vehicle is arranged on a horizontal plane, relative to gravity).

The bypass valve is preferably a thermostatic valve which can be switched as a function of a temperature of the first fluid.

In particular, the thermostat valve has a thermostat actuator, via which the thermostat valve or the bypass valve is switched. The thermostat actuator is arranged downstream of the first connection and the second connection and upstream of the outlet connection.

One possible embodiment of a thermostat valve comprises a housing which has a thermostat actuator filled with wax, liquid or gas inside. The thermostat actuator can comprise an expansion element which consists of a metal bellows similar to a corrugated pipe coupling or a corrugated pipe and expands in accordance with the temperature of the first fluid surrounding the thermostat actuator. This change in length can be transmitted to a transmission pin (plunger) and via this to the thermostatic valve, so that the thermostatic valve is actuated. A return spring can reset the thermostatic valve when the expansion body contracts.

The at least or precisely one ventilation connection is preferably arranged upstream of the thermostat actuator. In particular, the at least or precisely one ventilation connection is arranged downstream at least from the first connection and in particular also downstream from the second connection.

The cooling circuit preferably additionally has a second fluid circuit, which is connected via a second inlet connection and a second outlet connection to a second cooler for the passage of a second fluid through the second cooler.

The second fluid circuit is in particular a high-temperature circuit.

The second fluid conveyed in the high-temperature circuit has at least on average a higher temperature (at least 5 degrees Celsius) than the first fluid conveyed in the low-temperature circuit (at least during operation of the drive unit).

The first cooler and the second cooler form, in particular, what is known as a “combination cooler” (a combination cooler) which has two inlet connections and two outlet connections. For this purpose, the first cooler and the second cooler can be arranged in a common housing, with a (direct) fluidic connection between the first cooler and the second cooler preferably not being provided. It is possible that the first cooler and the second cooler are connected to one another via a connection, this connection then being provided (exclusively) for reducing thermal voltages. The exchange of fluid made possible via the connection between the first cooler and the second cooler can be designed to be limited for a fluid flow so that it does not exceed 5%, in particular a maximum of 1%, of the (maximum) flowing through the first cooler or through the second cooler. Fluid flow is.

The coolers can each have a (first or second) fluid (in particular cooling water, possibly also oil) flowing through them, the fluid in the coolers being able to be acted upon by an air stream for cooling.

In particular, the first cooler is arranged below the second cooler (when installed in the motor vehicle, when the motor vehicle is arranged on a horizontal plane, relative to gravity).

The second cooler can be arranged with the first cooler in particular in a common housing and (completely) above the first cooler.

In particular, the first cooler has no flow connection for the first fluid or the second fluid to the second cooler on. In particular, only the already mentioned connection for reducing thermal voltages is provided, and only an insignificant fluid flow can flow between the coolers via this connection.

In particular, the first fluid circuit and the second fluid circuit are fluidically connected to one another outside of the cooler via an expansion tank. In particular, the first fluid and the second fluid are fluids of the same type.

In particular, the at least (precisely) one ventilation connection is arranged at the highest point of the first fluid circuit (in the installed state in the motor vehicle, when the motor vehicle is arranged on a horizontal plane, relative to gravity). In particular, the lines connecting the first fluid circuit to the expansion tank are excluded from this.

1. i. Erfassen einer Temperatur des ersten Fluids (insbesondere über den Thermostataktor);
   und, wenn die Temperatur unterhalb einer (vorgegebenen) Mindesttemperatur liegt,
2. ii. (Nicht-)Betätigen des Bypass-Ventils und Leiten des ersten Fluids von dem ersten Zulaufanschluss hin zu dem ersten Ablaufanschluss unter Umgehung des ersten Kühlers;
   wobei, wenn die Temperatur die Mindesttemperatur erreicht hat oder darüberliegt,
3. iii. Betätigen des Bypass-Ventils und Durchleiten des ersten Fluids von dem ersten Zulaufanschluss über den ersten Kühler hin zu dem ersten Ablaufanschluss.

A method for operating the cooling circuit already described in a motor vehicle is also proposed. The method comprises at least the following steps:

1. i. Detecting a temperature of the first fluid (in particular via the thermostat actuator);
   and, if the temperature is below a (predetermined) minimum temperature,
2. ii. (Not) actuating the bypass valve and guiding the first fluid from the first inlet connection to the first outlet connection, bypassing the first cooler;
   where, when the temperature has reached or exceeded the minimum temperature,
3. iii. Actuation of the bypass valve and passage of the first fluid from the first inlet connection via the first cooler to the first outlet connection.

The minimum temperature is preferably between 35 and 50 degrees Celsius.

The minimum temperature can be specified via a control device and the temperature can be monitored via the control device. The bypass valve can also be actuated via the control device as a function of the temperature. The temperature can be measured via sensors and / or computed or determined by means of a control device or control unit on the basis of the current operating points of the motor vehicle or cooling circuit.

It is preferred that the minimum temperature is preset on the thermostat valve and that the thermostat valve is actuated accordingly via the thermostat actuator when the respective temperature is sensed.

The method can be carried out at least partially by a computer (control device).

A device or system for data processing (control device / control device) may be present, comprising a processor which is adapted or configured in such a way that it can or carries out the explained method.

A motor vehicle is also proposed with a drive unit for driving the motor vehicle and a cooling circuit already described, the drive unit being coolable via the second fluid circuit is. In particular, a third cooler is acted upon by the first fluid via the first fluid circuit. The third cooler is preferably a charge air cooler of the motor vehicle. Possibly. a control device is provided which is suitably designed and / or set up to carry out the method proposed here.

The statements on the cooling circuit apply equally to the method and the motor vehicle 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 a person skilled in the art when studying the specifically described embodiment.

Fig. 1:

ein Kraftfahrzeug mit einem Kühlkreislauf;

Fig. 2:

einen ersten Kühler und eine Bypassleitung in einer Frontalansicht;

Fig. 3:

den ersten Kühler und die Bypassleitung nach Fig. 2 in einer Seitenansicht;

Fig. 4:

ein Bypass-Ventil und Bypassleitung in einem ersten Schaltzustand in einer perspektivischen Ansicht;

Fig. 5:

das Bypass-Ventil und Bypassleitung nach Fig. 4 in einem zweiten Schaltzustand in einer perspektivischen Ansicht;

Fig. 6:

ein Bypass-Ventil in einer perspektivischen Ansicht; und

Fig. 7:

das Bypass-Ventil nach Fig. 6 in einer Seitenansicht im Schnitt.

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:

Fig. 1:

a motor vehicle with a cooling circuit;

Fig. 2:

a first cooler and a bypass line in a front view;

Fig. 3:

the first cooler and the bypass line Fig. 2 in a side view;

Fig. 4:

a bypass valve and bypass line in a first switching state in a perspective view;

Fig. 5:

the bypass valve and bypass line after Fig. 4 in a second switching state in a perspective view;

Fig. 6:

a bypass valve in a perspective view; and

Fig. 7:

the bypass valve Fig. 6 in a side view in section.

The Fig. 1 shows a motor vehicle 3 with a cooling circuit 1. The motor vehicle 3 comprises a drive unit 2 (e.g. an internal combustion engine) for driving the motor vehicle 3, a control device 27 and a cooling circuit 1. The drive unit 2 (e.g. B. cylinder head of an internal combustion engine or power unit of an electrical machine) can be cooled. A third cooler 30 (for example a water-cooled charge air cooler of an internal combustion engine or, in the case of an electrical machine as drive unit 2, a battery cooling unit) can be cooled via the first fluid circuit 4.

The cooling circuit 1 has a first fluid circuit 4 which, via a first inflow connection 5 and a first outflow connection 6, has a first cooler 7 for passing a first fluid 8 through the first Cooler 7 is connected. The first inlet connection 5 and the first outlet connection 6 are connected via a bypass line 9. The first fluid 8 can be diverted from the first inflow connection 5 to the first outflow connection 6 by bypassing the first cooler 7 via a bypass valve 10 of the bypass line 9. The bypass valve 10 has a vent connection 11 for venting the bypass line 9 and the first cooler 7.

With the bypass valve 10, the first fluid 8 can be diverted from the first inlet connection 5 to the second outlet connection 6, bypassing the first cooler 7. The bypass valve 10 can be controlled and operated via a control device 27, but it is preferably designed to be self-regulating. If the bypass valve 10 is switched so that the first cooler 7 is bypassed (see also Fig. 4 ), the first fluid 8 (for example after a cold start of the drive unit 2) can reach a specified minimum temperature more quickly. If the minimum temperature is reached, the bypass valve 10 can be switched so that the first fluid 8 is passed through the first cooler 7 and is thereby cooled (see FIG Fig. 5 ).

The bypass valve 10 is arranged downstream of the first cooler 7. The first inlet connection 5 and the first outlet connection 6 are arranged in such a way that the first cooler 7 can flow through the first fluid 8 from bottom to top (in the installed state in the motor vehicle 3, when the motor vehicle 3 is arranged on a horizontal plane, relative to gravity 39) is.

The cooling circuit 1 additionally has a second fluid circuit 19, which has a second inlet connection 20 and a second outlet connection 21 is connected to a second cooler 22 for passing a second fluid 23 through the second cooler 22.

Here, the first fluid circuit 4 and the second fluid circuit 19 are fluidically connected to one another outside the coolers 7, 22 via an expansion tank 25. The coolers 7, 22 each have a cooler housing 24.

The first fluid circuit 4 comprises a first pump 37. Starting from the first pump 37, a first cooler flow 29 extends to the first inlet connection 5. Starting from the first outlet connection 6, a first cooler return 31 extends to the third cooler 30. The third cooler is connected to the first pump 37 via a first line section 35. The first line section 35 is connected to the expansion tank 25 via a second line section 36. The vent connection 11 of the bypass valve 10 is connected to the expansion tank 25 via the first vent line 28.

The second fluid circuit 19 comprises a second pump 38. Starting from the second pump 38, a second cooler inlet 33 extends to the second inlet connection 20. Starting from the second outlet connection 21, a second cooler return 34 extends to the drive unit 2 or to the second pump 38. The second cooler flow 33 is connected to the expansion tank 25 via a second vent line 32.

Fig. 2 shows a first cooler 7 and a bypass line 9 in a plan view. Fig. 3 shows the first cooler 7 and the bypass line 9 Fig. 2 in a side view. The Figs. 2 and 3 are described together below. On the remarks too Fig. 1 is referred to.

The first fluid circuit 4 is connected via a first inlet connection 5 and a first outlet connection 6 to a first cooler 7 for passing a first fluid 8 through the first cooler 7. The first inlet connection 5 and the first outlet connection 6 are connected via a bypass line 9. The first fluid 8 can be diverted from the first inflow connection 5 to the first outflow connection 6 by bypassing the first cooler 7 via a bypass valve 10 of the bypass line 9. The bypass valve 10 has a vent connection 11 for venting the bypass line 9 and the first cooler 7.

Exactly one vent connection 11 is arranged at the highest point of the first fluid circuit 4 (in the installed state in the motor vehicle 3, when the motor vehicle 3 is arranged on a horizontal plane, relative to gravity 39).

The bypass valve 10 has a housing 12 with an outlet connection 13 for forwarding the first fluid 8 (e.g. to a third cooler 22), with a first connection 14 for connecting the bypass valve 10 to the first cooler 7 (where the first cooler 7 is arranged upstream of the first connection 14) and with a second connection 15 for connecting the bypass valve 10 to the first inlet connection 5 (wherein the first inlet connection 5 is arranged upstream of the second connection 15). The housing 12 also has the one ventilation connection 11.

The first cooler 7 is connected to the bypass valve 10 via a first drain line 16, the first drain line 16 (e.g. starting from the heat exchanger structure of the first cooler 7) leading to the bypass valve 10, e.g. B. towards the first connection 14, and to the venting connection 11 increasing (in the installed state in the motor vehicle 3, when the motor vehicle 3 is arranged on a horizontal plane, relative to the force of gravity 39), that is to say at an angle 26 to the horizontal plane.

Fig. 4 shows a bypass valve 10 and bypass line 9 in a first switching state in a perspective view. Here the first fluid 8 enters the housing 12 of the bypass valve 10 via the second connection 15 (bypassing the first cooler 7). The first fluid 8 leaves the housing 12 via the outlet connection 13.

Fig. 5 shows the bypass valve 10 and bypass line 9 Fig. 4 in a second switching state in a perspective view. Here, the first fluid 8 enters the housing 12 of the bypass valve 10 via the first connection 14 (starting from the first cooler 7). The first fluid 8 leaves the housing 12 via the outlet connection 13.

Fig. 6 shows a bypass valve 10 in a perspective view. Fig. 7 shows the bypass valve 10 Fig. 6 in a side view in section. The Figures 6 and 7 are described together below. On the remarks on the Figs. 1 to 5 is referred to.

Here the bypass valve 10 is designed as a thermostatic valve that can be switched as a function of a temperature 17 of the first fluid 8.

The thermostatic valve has a thermostat actuator 18, via which the thermostatic valve or the bypass valve 10 is switched. The thermostat actuator 18 is arranged downstream of the first connection 14 and the second connection 15 and upstream of the outlet connection 13.

The one ventilation connection 11 is arranged upstream of the thermostat actuator 18. The ventilation connection 11 is arranged downstream of the first connection 14 and the second connection 15.

In the method, in a step i. a temperature 17 of the first fluid 8 is detected and, if the temperature 17 is below a minimum temperature, in a step ii. the bypass valve 10 is actuated and the first fluid 8 is conducted from the first inlet connection 5 to the first outlet connection 6 via the bypass line 9, bypassing the first cooler 7 (first switching state). If the temperature 17 has reached the minimum temperature or is above, in a step iii. the bypass valve 10 is actuated and the first fluid 8 is conducted from the first inlet connection 5 via the first cooler 7 and towards the first outlet connection 6 (second switching state). The minimum temperature can be specified via a control device 27 and the temperature 17 can be monitored via the control device 27. The bypass valve 10 can be actuated via the control device 27 as a function of the temperature 17. Alternatively, the thermostat valve can switch automatically via the thermostat actuator 18.

List of reference symbols

1

Cooling circuit

2

Drive unit

3

Motor vehicle

4th

first fluid circuit

5

first inlet connection

6

first drain connection

7th

first cooler

8th

first fluid

9

Bypass line

10

Bypass valve

11

Vent connection

12

casing

13

Outlet connection

14th

first connection

15th

second connection

16

first drain line

17th

temperature

18th

Thermostat actuator

19th

second fluid circuit

20th

second inlet connection

21st

second drain connection

22nd

second cooler

23

second fluid

24

Radiator housing

25th

surge tank

26th

angle

27

Control device

28

first vent line

29

first cooler flow

30th

third cooler

31

first cooler return

32

second vent line

33

second cooler flow

34

second cooler return

35

first line section

36

second line section

37

first pump

38

second pump

39

Gravity

Claims (11)

1. Cooling circuit (1) of a drive unit (2) of a motor vehicle (3), at least having a first fluid circuit (4), which is connected via a first feed connector (5) and a first discharge connector (6) to a first radiator (7) for the purposes of conducting a first fluid (8) through the first radiator (7); wherein the first feed connector (5) and the first discharge connector (6) are connected via a bypass line (9); wherein, via a bypass valve (10), the first fluid (8) can be diverted from the first feed connector (5) to the first discharge connector (6) so as to bypass the first radiator (7); wherein the bypass valve (10) has at least one ventilation connector (11) for the ventilation of at least the bypass line (9); characterized in that the first feed connector (5) and the first discharge connector (6) are arranged such that the first radiator (7) can be flowed through by the first fluid (8) from bottom to top; wherein the first radiator (7) is connected to the bypass valve (10) via a first discharge line (16), wherein the first discharge line (16) runs in a rising manner to the bypass valve (10) and to the at least one ventilation connector (11).
2. Cooling circuit (1) according to Patent Claim 1, wherein the bypass valve (10) is arranged downstream of the first radiator (7).
3. Cooling circuit (1) according to any of the preceding patent claims, wherein ventilation of the first radiator (7) is additionally made possible via the at least one ventilation connector (11).
4. Cooling circuit (1) according to any of the preceding patent claims, wherein the bypass valve (10) has a housing (12) with an outlet connector (13) for conducting the first fluid (8) onwards, having a first connector (14) for connecting the bypass valve (10) to the first radiator (7), and having a second connector (15) for connecting the bypass valve (10) to the first feed connector (5), wherein the housing (12) additionally has the at least one ventilation connector (11).
5. Cooling circuit (1) according to any of the preceding patent claims, wherein the bypass valve (10) is a thermostat valve which is switchable in a manner dependent on a temperature (17) of the first fluid (8).
6. Cooling circuit (1) according to Patent Claim 5, wherein the at least one ventilation connector (11) is arranged upstream of a thermostat actuator (18).
7. Cooling circuit (1) according to any of the preceding patent claims, wherein the cooling circuit (1) additionally has a second fluid circuit (19) which is connected via a second feed connector (20) and a second discharge connector (21) to a second radiator (22) for the purposes of conducting a second fluid (23) through the second radiator (22); wherein the second radiator (22) is arranged with the first radiator (7) in a common radiator housing (24) and is arranged above the first radiator (7).
8. Cooling circuit (1) according to Patent Claim 7, wherein the first radiator (7) has no connection in terms of flow for the first fluid (8) or the second fluid (23) to the second radiator (22).
9. Cooling circuit (1) according to any of the preceding patent claims, wherein the first fluid circuit (4) and the second fluid circuit (19) are connected to one another in terms of flow exclusively outside the radiators (7, 22) via an expansion tank (25).
10. Method for operating a cooling circuit (1) according to any of the preceding patent claims in a motor vehicle (3), wherein the method comprises at least the following steps:

    i. detecting a temperature (17) of the first fluid (8);
    and, if the temperature (17) lies below a minimum temperature,

    ii. actuating the bypass valve (10) and diverting the first fluid (8) from the first feed connector (5) to the first discharge connector (6) so as to bypass the first radiator (7);
    wherein, if the temperature (17) has reached or lies above the minimum temperature,

    iii. actuating the bypass valve (10) and conducting the first fluid (8) through from the first feed connector (5) via the first radiator (7) to the first discharge connector (6) .
11. Method according to Patent Claim 10, wherein the minimum temperature amounts to between 35 and 50 degrees Celsius.

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