DE102015220095B3 - Cooling system for at least one component of a vehicle and method for operating such a cooling system - Google Patents

Abstract

The cooling system according to the invention for at least one component (2) of a vehicle (1) comprises a reservoir (5) for a coolant, a conduit system (3) for the coolant with at least one line (4) arranged in the component (2), and an in the conduit (3) arranged pump (6) for pumping the coolant through the conduit (4). It also comprises a sensor (21), by means of which a loss of coolant from the line system (3) can be detected and sensor signals can be generated, and a control unit (20) coupled to the pump (6) and the sensor (21) Based on the sensor signals, a control signal can be generated. In this case, the pump (6) in the flow direction (F) of the coolant behind the component (2) and in the flow direction (F) of the coolant in front of the component (2) is a with the control unit (20) coupled shut-off valve (7) in the Line (4) arranged, by means of which by means of the control signal, the flow of the coolant through the conduit (4) can be shut off. The invention further comprises a method for operating a cooling system and a vehicle (1).

Description

The present invention relates to a cooling system for at least one component of a vehicle and to a method for operating such a cooling system. It further relates to a vehicle with such a cooling system. The cooling system according to the invention comprises a reservoir for a coolant and a conduit system for the coolant with at least one line arranged in the component. It further comprises a pump arranged in the conduit system in the direction of flow of the coolant behind the component for pumping the coolant through the conduit, a sensor by which a loss of coolant from the conduit system can be detected and sensor signals can be generated, and one with the pump and the Sensor coupled control unit, by means of which a control signal can be generated on the basis of the sensor signals. It also comprises a shut-off valve coupled to the control unit, which is arranged upstream of the component in the line in the direction of flow of the coolant.

In order to keep the operating temperature of electrical and electronic components in vehicles below the maximum permissible limits, liquid cooling, for example with a water-glycol mixture as coolant, is used in many cases. This is particularly important in vehicles with electric motor and hybrid vehicles of importance, since large powers are transmitted, typically high waste heat.

In the in the DE 197 30 678 A1 proposed hybrid vehicle, a device for cooling a high-temperature battery and the interior heating is provided. The heat-emitting components and the interior heating are connected by a fluid circuit. Here, a pump is provided downstream of the high-temperature battery and a valve upstream thereof.

The DE 10 2006 032 852 A1 describes a water-cooled engine with multiple cooling circuits, wherein a temperature compensation tank is provided which has a medium for air compensation and for storing heat.

In the DE 10 2011 117 054 A1 In addition, a device for recovering energy from a waste heat stream of an internal combustion engine in a vehicle with a working medium circuit is proposed. In this case, a working fluid container is provided, the filling level can be determined and compared with a Sollfüllhöhe.

The DE 10 2008 0192 27 A1 describes a method for compensating the thermal expansion in a coolant circuit. In this case, a sensor device is provided which detects a level parameter, wherein a compensation device is controlled so that a quantity of coolant is sucked off or metered in such a way that a predetermined coolant level is reached.

The in the DE 10 2011 118 162 A1 described refrigeration system and heat pump allows a flexible distribution of refrigerant within the system depending on the needs, the refrigerant charge in the various areas of the system can be controlled.

Production or assembly errors as well as the aging of subcomponents such as hoses and seals can lead to a risk of leakage, in which coolant can escape. If the cooling circuit is in close proximity to or within the component to be cooled to improve the thermal contact, the leakage may cause damage and in particular short circuits that result in partial or complete destruction of the component.

It is therefore of great importance in the application of liquid-cooled components in a vehicle to detect a leak early and to prevent the direct contact of the components with the coolant as much as possible.

In the in the DE 10 2012 204 832 A1 described method for reducing the risk of short circuit on an electrical component circulates a cooling fluid and cools an electrical component through a cooling plate. When a leak is detected, a valve in the fluid circuit opens, draining the coolant from the system.

The DE 10 2013 221 137 B3 describes a cooling system for a vehicle battery, in which a negative pressure in the battery area is generated. By comparing the applied negative pressure with the actual measured pressure, a leak can be detected. In this case, the negative pressure can prevent leakage of the cooling liquid, and at the same time, the circulation of the coolant can be continued.

It is the object of the invention to provide a cooling system and a method for operating such a cooling system, in which a leak is quickly detected and with which a leakage of coolant is avoided as possible.

According to the invention this object is achieved by a cooling system with the features of claim 1 and by a method for operating a cooling system with the features of claim 6 and solved by a vehicle with such a cooling system according to claim 10.

The cooling system according to the invention is characterized in that the shut-off valve is adapted to shut off the flow of the coolant through the line on the basis of the control signal, and the pump is arranged to use the control signal to pump off the coolant remaining in the line, the reservoir being suitable. to absorb the pumped coolant.

There are several steps involved in handling leaks: First, the leak must be detected and a warning message can be issued if necessary, such as a warning light or a warning tone. This can be done in various ways, such as by a pressure change when the closed system to the environment has a negative or positive pressure, or by the leakage of the coolant, about as loss of existing in the piping system volume or by moisture in the vicinity of the leak can be detected. In this case, the position of the leakage opening can be more or less accurately located by various methods. In particular, such leaks are important, which are in the immediate vicinity of components to be protected, since there emerging coolant can come into contact with these components. This pertains in a special way to lines which run through the component for improving the thermal contact or are integrated in a cooling device arranged directly on the component. However, even with a leak at any point of the line system, a quick treatment of the problem is necessary because escaping coolant can also pose a risk for components in greater spatial distance and because a reduced cooling capacity can lead to overheating of the components to be cooled.

In a further step, the flow of the coolant is passivated in the region of the leak, that is, it is avoided that the coolant is pumped to the leak, which would lead to increased leakage. Furthermore, the coolant outlet is to be prevented by the leakage opening, since the line volume and thus the amount of coolant contained therein is usually large enough to represent a risk to the component at the outlet.

According to the invention it is proposed to arrange a suction pump behind the component to be cooled. If there is now a leak in the region of the component which is arranged in front of the pump, the pump can transport coolant from the line away from the leakage opening. By contrast, a pressure pump arranged in front of the component, as prevalent in conventional systems, would lead to coolant being transported towards the leakage opening, which can lead to increased leakage.

Furthermore, according to the invention, a shut-off valve is arranged upstream of the component in the direction of flow. By closing this valve can be additionally prevented that additional coolant flows to a leakage opening in the region of the component or is pumped.

After the detection and treatment of the leak, a safe operating mode of the vehicle may be activated, for example, in which the cooling system is deactivated. In this case, the component to be cooled can be deactivated to prevent overheating.

The component is in particular a high-voltage (HV) battery, an AC converter or a charger of an electric or hybrid vehicle. In a cooling system in a hybrid vehicle, which also has an internal combustion engine in addition to an electric drive, the operation of the internal combustion engine can optionally be continued while the electric drive is deactivated to protect the component to be cooled.

Furthermore, the cooling system according to the invention can have different coolant circuits with lines for different critical components of the vehicle. These can be coupled together or operated separately. In this case, the inventive protection against leaks can be applied separately to several components.

According to the invention, the pump is set up to pump off the coolant remaining in the line on the basis of the control signal, and the reservoir is suitable for receiving the pumped-off coolant. The volume of coolant which is pumped out of the line after the detection of a leak is thereby advantageously taken up by the reservoir. In addition, another container may be provided for receiving the pumped coolant.

In a further development of the invention, the line system further comprises a bypass line, which is arranged between a position which is located between the shut-off valve and the component, and a position behind the component. In particular, the bypass line extends outside the region of the component, so that the coolant can be conducted past the component. In case of a leakage in the area of the component can thus advantageously the coolant between the leakage and shut-off valve are actively pumped before it passively, for example, by vibrations or temperature fluctuations, exits. This is of particular importance where the line is in the immediate vicinity of the component or within the component.

In a further embodiment, the bypass line has a line cross section which is small relative to the line cross section of the line. As a result, advantageously only a small volume of the coolant can flow through the bypass line when the line between the connection points of the bypass line is intact. However, if there is a leak here, the negative pressure generated by the suction pump allows pumping of the coolant between the shut-off valve and the leak. In particular, the cross-sectional area of the bypass line is less than 5% of the cross-sectional area of the line.

In a further embodiment, a bypass shut-off valve coupled to the control unit is further arranged in the bypass line. As a result, the bypass line can advantageously be selectively opened and closed. In this case, the coolant only flows through the bypass line when the bypass shut-off valve has been opened, and there is no loss of cooling capacity when the bypass shut-off valve is closed. The opening and closing of the bypass shut-off valve is in particular triggered by a control signal of the control unit, which is generated upon detection of a leak.

In the method according to the invention for operating a cooling system for at least one component of a vehicle, a loss of coolant from a line system is detected by a sensor and sensor signals are generated. In this case, the line system comprises at least one arranged in the component line. By a control unit, based on the sensor signals, a control signal is generated so that the flow of the coolant through the conduit at a position in the flow direction of the coolant is shut off from the component and the coolant remaining in the conduit is pumped out.

The method is implemented in particular by the above-described cooling system according to the invention. The method thus has the same advantages as the cooling system according to the invention.

The coolant can be pumped from the line into a reservoir, advantageously the excess volume is removed from the conduit system.

In a further embodiment, the sensor detects a level in the reservoir. The loss of coolant from the piping system is determined by the level. This advantageously allows a simple determination of the coolant volume present in the line system. In particular, it is possible to detect a drop in the total volume and to deduce a leak therefrom. This detection is particularly easy to integrate into existing vehicles, since they typically already have such a sensor, for example, to detect escaping by evaporation coolant.

After the detection of a leak, a warning message can be issued, for example by means of a warning light or an acoustic warning signal.

In particular, the level can be detected by the sensor automatically at certain intervals. As a result, the temporal development of the fill level is advantageously detected and, for example, a slow reduction of the coolant volume by evaporation can be distinguished from a rapid drop in the fill level in the event of a leak.

In a further embodiment of the method according to the invention, the coolant remaining in the line is also pumped out when deactivating the cooling system. This allows a precautionary emptying of the line when no cooling is needed. For example, this can be done when parking the vehicle when the component is not operated and therefore no heat is generated. The coolant is in conventional cooling systems in the line system, in particular in the line at the component, left and so can leak in the sudden occurrence of a leak, such as a marten bite.

In particular, when restarting the cooling system by another pump again coolant can be pumped into the line and the pump behind the component will be put back into operation only when the coolant has reached them in order to avoid that the speed of the pump the maximum allowable Value exceeds and pump damage occurs or unpleasant noise emissions are generated. The time at which the coolant in the line reaches the pump can be estimated, for example, from the volume of coolant in the reservoir.

The vehicle according to the invention comprises a cooling system according to the invention for carrying out the method according to the invention.

The invention will now be explained by means of embodiments with reference to the drawings.

1 shows a vehicle with a first embodiment of the cooling system according to the invention,

2 shows a vehicle with a second embodiment of the cooling system according to the invention with a bypass line and a bypass stop valve,

3 shows a vehicle with a third embodiment of the cooling system according to the invention with a bypass line with a small line cross section and

4 shows a vehicle with a fourth embodiment of the cooling system according to the invention with different components in separate coolant circuits.

In reference to 1 a vehicle is explained with a first embodiment of the cooling system according to the invention.

A vehicle 1 includes a component 2 , in the illustrated exemplary case, this is a high-voltage (HV) battery 2 , A line 4 a pipe system 3 passes through the HV battery 2 and is in thermal contact with it, so that heat from the HV battery 2 to a coolant in the pipe 4 is transmitted. The coolant is by means of the suction pump 6 in the flow direction F through the pipe system 3 pumped, with the suction pump 6 behind the HV battery 2 is arranged. In the pipe system 3 in front of the HV battery 2 is a shut-off valve 7 arranged through which the flow of coolant through the pipe 4 can be interrupted. The shut-off valve 7 can be designed as a control valve, in which case a partial shut-off is possible. In the illustrated embodiment, the line runs 4 from the shut-off valve 7 to the suction pump 6 , To the pipe system 3 is also a reservoir 5 connected for the coolant. In this storage container 5 can excess coolant from the piping system 3 stored and, if necessary, the piping system 3 to provide.

The cooling system further includes a level sensor 21 indicating the level of the reservoir 5 detected. This happens in particular at regular intervals. Furthermore, the cooling system comprises a control unit 20 , with which the level sensor 21 , the suction pump 6 and the shut-off valve 7 are coupled. The cooling system further includes other components, such as for cooling the coolant, which are not shown for clarity here.

It will now be the execution of the method according to the invention by the in 1 illustrated cooling system explained.

When the cooling system is activated, in particular while the vehicle 1 drives and on the HV battery 2 arising heat must be dissipated, the coolant by means of the suction pump 6 in the flow direction F through the pipe system 3 pumped. The administration 4 of the pipe system 3 passes through the HV battery 2 and allows heat transfer to the coolant.

A coolant supply in the reservoir 5 serves to ensure that the conduit system 3 is always filled with coolant and reductions or increases in volume, such as temperature fluctuations or evaporation, are compensated. The level of the reservoir 5 is periodically through the level sensor 21 measured. Based on the level sensor 21 recorded data will be a loss of coolant from the piping system 3 detected. In particular, the above-mentioned fluctuations of the coolant volume, which are not due to a leak, are taken into account. For example, a limit for the level can be set. If the limit value is undershot, this is interpreted as an indication that coolant is due to a leak in the pipe system 3 exit. Alternatively or additionally, it can be taken into account how quickly the fill level changes. For example, it can be distinguished whether coolant slowly evaporates or leaks quickly through a leak.

In further embodiments, the position of a leak in the piping system 3 determined, for example by leakage sensors, especially in critical areas, such as the line 4 near the HV battery 2 ,

After the detection of a leak, especially if there is a leak in the area of the line 4 in the HV battery 2 was detected, a sensor signal is generated and sent to the control unit 20 transfer. This in turn generates a control signal, through which initially the shut-off valve 7 is closed. There can not be any more coolant in the pipe 4 be pumped as these flow in the direction F behind the shut-off valve 7 is arranged. The suction pump 6 pumps at the same time, so that in the line 4 contained coolant is sucked. Excess volume in the pipe system 3 gets into the reservoir 5 pumped.

Once identified, that was the level of the reservoir 5 despite active suction pump 6 no longer rising, it can be assumed that the line 4 in the HV battery area 2 has been emptied, so that a passivation of the suction pump 6 can be done. Before restarting the system, after correcting leakage and refilling the piping system 3 a vent occurs.

Is the leak between the shut-off valve 7 and the suction pump 6 This is how the line is made 4 between the leak and the suction pump 6 emptied. At the same time, closing the shut-off valve 7 the flow between the shut-off valve 7 and the leak passivated, that is, the coolant is not actively pumped to the leak, but may leak due to, for example, temperature variations and vibration. The closer a leak in the pipe 4 at the suction pump 6 The larger the volume of the remaining coolant, which can escape passively in this way.

In reference to 2 a vehicle is explained with a second embodiment of the cooling system according to the invention with a bypass line and a bypass stop valve.

This in 2 illustrated vehicle 1 is essentially the same as above 1 described. In contrast, however, is in the line 4 a bypass line 8th provided in front of the HV battery 2 begins and ends after her. In this bypass line 8th is also a bypass stop valve 9 arranged. Further, the bypass check valve 9 with the control unit 20 coupled, however, for the sake of clarity of the level sensor 21 and the control unit 20 in 2 not shown. The bypass stop valve 9 is closed during normal operation of the cooling system and can be controlled by the control unit 20 be opened.

It will now be the execution of the method according to the invention by the in 2 illustrated cooling system explained.

The detection of a leak is described above with reference to 1 described. If a leak is detected, then the in 2 illustrated embodiment, the shut-off valve 7 closed while the suction pump 6 the coolant from the line 4 inflated. Unlike the in 1 shown cooling system can, however, through the bypass line 8th also the residual volume of the line 4 between the leak and the shut-off valve 7 be pumped, provided that the leak between the joints of the bypass line 8th with the line 4 is located, ie in the area of the HV battery 2 , This is the normally closed bypass stop valve 9 opened so that the suction pump the coolant through both the pipe 4 as well as through the bypass line 8th pumps off.

In reference to 3 a vehicle is explained with a third embodiment of the cooling system according to the invention with a bypass line with a small line cross-section.

The vehicle 1 corresponds to the above with reference to 2 described with the difference that in the bypass line 8th no bypass shut-off valve 9 is arranged. For the bypass line has 8th here one opposite the line 4 significantly lower cable cross-section. In particular, the cross-sectional area of the bypass line 8th less than 5% of the cross-sectional area of the pipe 4 , As the flow resistance in pipes and hoses increases with decreasing diameter, due to the small diameter of the bypass line flows 8th only a negligible flow of the coolant through the bypass line 8th compared to the line 4 so that only very little coolant is transported past the HV battery and most of it is available for cooling the HV battery.

In the case of identified leakage, in particular between the connection points of the bypass line 8th , the shut-off valve 7 closed. The suction pump 6 is activated and sucks coolant volume according to the ratio of the pipe diameter of the pipe 4 and the bypass line 8th from. That is, initially there is primarily an emptying of the lying behind the leak part of the line 4 , After draining this part of the pipe 4 is completed, the suction pump 6 continued to be active, so even the part of the line 4 can be emptied before the leak. This is done via the bypass line 8th while passing through the part of the pipe behind the leak 4 only the air sucked in via the leakage opening is transported.

This variant can be cheaper than the one in 2 shown executed, as no additional bypass shut-off valve 9 is used.

In reference to 4 a vehicle is explained with a fourth embodiment of the cooling system according to the invention with different components in separate coolant circuits.

This in 4 illustrated vehicle 1 is essentially the same as above 1 described, for reasons of clarity of the level sensor 21 and the control unit 20 are not shown. In contrast to 1 is however in the management system 3 another partial circuit with a pressure pump 10 provided for the coolant, in which a power electronics 11 , a charger 12 and a low temperature cooler 13 are arranged so that these components are in thermal contact with the coolant. Furthermore, one is in the line 4 arranged chiller 14 intended. The components 2 . 11 . 12 . 13 . 14 are doing in different areas of the vehicle 1 arranged, namely in the area of a front end 1a and a subfloor 1b , wherein in particular the HV battery in the area of the subsoil 1b is arranged while the other components 11 . 12 . 13 . 14 in the area of the front end 1a are arranged.

By the arrangement of the HV battery 2 in a separate subcircuit, the volume flow of the cooling medium through the line 4 in the HV battery 2 in driving conditions and / or in environmental conditions that do not cool the HV battery 2 be passivated, with the coolant is not actively pumped in this area. This may for example be the case when the vehicle is operated with an alternative drive, such as a hybrid engine. Furthermore, it is possible to control the volume flow of the cooling medium through the HV battery 2 to control demand by the shut-off valve 7 opened and the suction pump 6 is operated according to the current cooling demand.

The arrangement of the suction pump 6 behind the HV battery 2 allowed in connection with the shut-off valve 7 in front of the HV battery 2 a protective reaction with a coolant leak, especially in the HV battery 2 , If a leak is detected, then the shut-off valve 7 closed and the suction pump 6 pumps the coolant from the line 4 in which the HV battery 2 is arranged in the reservoir 5 ,

Similarly, in other embodiments, separate sub-circuits for the coolant for one or more other components 2 . 11 . 12 . 13 . 14 of the system, so that a targeted emptying of a part of the piping system 3 can be done to the respective component 2 . 11 . 12 . 13 . 14 to protect in case of leakage.

In a further embodiment, the coolant in a parked vehicle prophylactically using the described method from the partial cooling circuit of the HV battery 2 removed and the coolant in the reservoir 5 pumped. When re-starting after a vehicle stance phase, initially transported only the pressure pump 10 Coolant through the cooling circuit of the power electronics 11 , the charger 12 and the low temperature cooler 13 , Over the open shut-off valve 7 but also coolant in the cooling circuit of the HV battery 2 pumped. After a certain time, the coolant also reaches the suction pump 6 and is sucked by this, so that the required flow rate of the coolant through the line 4 in the HV battery area 2 established. Alternatively, the suction pump 6 when starting for a vehicle service life initially for a predefined time, within which it is assumed that at her still no cooling medium has arrived, remain disabled. As a result, it can be avoided that the operation in air causes high speeds, which are the suction pump 6 could damage.

LIST OF REFERENCE NUMBERS

1

vehicle

1a

front end

1b

underbody

2

Component, high-voltage battery

3

line system

4

management

5

reservoir

6

suction pump

7

shut-off valve

8th

bypass line

9

Bypass shutoff valve

10

pressure pump

11

power electronics

12

charger

13

Low-temperature cooler

14

refrigeration machine

20

control unit

21

level sensor

F

Arrow, flow direction of the coolant

Claims (9)

Cooling system for at least one component ( 2 ) of a vehicle ( 1 ), comprising a reservoir ( 5 ) for a coolant; a pipe system ( 3 ) for the coolant with at least one component ( 2 ) arranged line ( 4 ); one in the piping system ( 3 ) in the flow direction (F) of the coolant behind the component ( 2 ) arranged pump ( 6 ) for pumping the coolant through the conduit ( 4 ); a sensor ( 21 ), through which a loss of coolant from the piping system ( 3 ) is detectable and sensor signals can be generated; one with the pump ( 6 ) and the sensor ( 21 ) coupled control unit ( 20 ), by means of which a control signal can be generated on the basis of the sensor signals; and one with the control unit ( 20 ) coupled shut-off valve ( 7 ), which in the flow direction (F) of the coolant before the component ( 2 ) in the line ( 4 ), characterized in that the shut-off valve ( 7 ) is arranged, based on the control signal, the flow of the coolant through the line ( 4 ) and the pump ( 6 ) is adapted, based on the control signal in the line ( 4 ) to pump off remaining coolant, wherein the Reservoir ( 5 ) is adapted to receive the pumped coolant. Cooling system according to claim 1, characterized in that the conduit system ( 3 ) further comprises a bypass line ( 8th ) between a position between the shut-off valve ( 7 ) and the component ( 2 ) on the one hand and a position behind the component ( 2 ) is arranged on the other hand. Cooling system according to claim 2, characterized in that the bypass line ( 8th ) has a line cross section which is relative to the line cross section of the line ( 4 ) is small. Cooling system according to claim 2 or 3, characterized in that further comprises a with the control unit ( 20 ) coupled bypass stop valve ( 9 ) in the bypass line ( 8th ) is arranged. Method for operating a cooling system for at least one component ( 2 ) of a vehicle ( 1 ), in which by a sensor ( 21 ) a loss of coolant from a piping system ( 3 ) is detected and sensor signals are generated, wherein the line system ( 3 ) at least one in the component ( 2 ) arranged line ( 4 ), and by a control unit ( 20 ) is generated from the sensor signals, a control signal so that the flow of the coolant through the line ( 4 ) at a position in the flow direction (F) of the coolant before the component ( 2 ) and that in the line ( 4 ) is pumped out remaining coolant. Method according to claim 5, characterized in that the sensor ( 21 ) a level in the reservoir ( 5 ) and the loss of coolant from the piping system ( 3 ) is determined by the level. A method according to claim 6, characterized in that the level by the sensor ( 21 ) is detected automatically at certain intervals. Method according to one of claims 5 to 7, characterized in that in the line ( 4 ) remaining coolant is further pumped out when deactivating the cooling system. Vehicle ( 1 ) with a cooling system according to one of claims 1 to 4.

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