Air conditioning unit with protective container to contain a refrigerant circuit through which a flammable refrigerant flows, and motor vehicle

Abstract

The invention relates to an air conditioning unit (10) for a motor vehicle, comprising a refrigerant circuit (14) which includes a compressor (16) for conveying a flammable refrigerant to a refrigerant cooler (18) of the refrigerant circuit (14). The refrigerant circuit (14) includes an expansion device (20) for expanding the refrigerant coming from the refrigerant cooler (18) and an evaporator (22) which can be pressurized with the expanded refrigerant during operation of the refrigerant circuit (14). The air conditioning unit (10) includes a container (36) in which those components of the refrigerant circuit (14) are protected and can be exposed to the flammable refrigerant during operation of the refrigerant circuit (14). The invention further relates to a motor vehicle with such an air conditioning unit (10).

Description

[0001] The invention relates to an air conditioning system for a motor vehicle, comprising a refrigerant circuit which includes a compressor for conveying a flammable refrigerant to a refrigerant cooler of the refrigerant circuit. The refrigerant circuit includes an expansion device for expanding the refrigerant coming from the refrigerant cooler and an evaporator which can be pressurized with the expanded refrigerant. The invention further relates to a motor vehicle with such an air conditioning system.

[0002] Various refrigerants can be used in refrigerant circuits in motor vehicles. In the course of efforts to avoid refrigerants in the form of fluorinated alkyl compounds, natural refrigerants such as R744 (CO2) and flammable refrigerants in the form of hydrocarbons such as R290 (propane) are being considered.

[0003] DE 10 2014 112 545 A1 describes a compact air conditioning unit for a motor vehicle, wherein a primary refrigerant circuit of the compact unit is filled with a flammable refrigerant. The compact unit is enclosed in a housing. An outlet on the underside of the housing is designed as an outlet valve, which is electrically controllable via a supply line. A control unit receives sensor data from a pressure sensor, a temperature sensor, and a gas sensor, as well as information from crash sensors. If an anomaly occurs in the operation of the compact unit, the outlet valve can be opened as one possible measure.

[0004] WO 2021 / 048095 A1 describes a compact module for the temperature control of a motor vehicle, in which a primary circuit is designed as a refrigerant circuit for propane. In the event of a particularly severe collision in which the primary circuit loses its seal, an active pressure relief system is provided in the primary circuit. This active pressure relief system is triggered by a signal from a control unit. The escaping refrigerant is ignited by an ignition spark or a glow plug, which is powered by the vehicle's electrical system.

[0005] German patent DE 10 2008 010 024 A1 describes a safety device for an air conditioning system located partially outside the passenger compartment of a motor vehicle. The safety device comprises a system for detecting leaks in the air conditioning system's refrigerant circuit and a fire protection device. The fire protection device allows potential fire hazards in the engine compartment to be treated with a fire-retardant medium. To reduce the risk of fire in the engine compartment when using flammable refrigerants, the safety device can include a container filled with the fire-retardant medium, which is positioned in the engine compartment area.

[0006] A disadvantage here is that, despite the provision of fire protection equipment, a release of flammable refrigerant in the engine compartment is unfavorable.

[0007] The object of the present invention is to provide an air conditioning device of the type mentioned at the outset, which entails a simplified use of a flammable refrigerant, and to provide a motor vehicle with such an air conditioning device.

[0008] This problem is solved by an air conditioning device with the features of claim 1 and by a motor vehicle with the features of claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims and in the following description.

[0009] The air conditioning system according to the invention for a motor vehicle comprises a refrigerant circuit. The refrigerant circuit includes a compressor for conveying a flammable refrigerant to a refrigerant cooler of the refrigerant circuit. The refrigerant circuit includes an expansion device for reducing the pressure of the refrigerant coming from the refrigerant cooler and an evaporator. The evaporator can be pressurized with the expanded refrigerant during operation of the refrigerant circuit. The air conditioning system includes a container in which those components of the refrigerant circuit are protected and arranged which are exposed to the flammable refrigerant during operation of the refrigerant circuit.

[0010] The container ensures that even if flammable refrigerant leaks from the refrigerant circuit, it can be contained, at least temporarily, within the container. This prevents an uncontrolled release of flammable refrigerant into the surrounding area. Consequently, the air conditioning system facilitates the use of a flammable refrigerant in the refrigerant circuit.

[0011] The container has a valve, and the air conditioning system's control unit allows the valve to be at least partially opened. The valve is designed to release refrigerant from the container in the event of a leak in the refrigerant circuit. By providing this valve, even if flammable refrigerant escapes from the refrigerant circuit, the refrigerant can be released from the container into its surroundings in a controlled manner. This ensures that there is no risk of ignition of a mixture of refrigerant and air or ambient air in the vicinity of the container.

[0012] The control unit is designed to evaluate a signal from at least one impact sensor of the vehicle. This allows the control unit to check whether conditions exist that indicate an impending or ongoing accident involving the vehicle, when the air conditioning unit is installed in the vehicle. In particular, the control unit can actuate the valve depending on the evaluation of the signal from the at least one impact sensor. This is advantageous.

[0013] The control unit is designed to detect damage to a line connected to the valve and / or damage to the container based on the signal from at least one impact sensor. Depending on the damage, the control unit is then configured to actuate the valve. This allows the mixture containing the flammable refrigerant to be released from the container into the environment in a highly situation-appropriate manner.

[0014] For example, the control unit can detect a minor impact by evaluating the signal from the impact sensor, where damage to the pipe or container is not expected. Then, depending particularly on the severity of the refrigerant leak, the mixture can be released into the environment by actuating the valve.

[0015] If, for example, a moderate impact damages the line, the release of the mixture into the environment can be adjusted to the severity of the impact. For instance, based on the signal from at least one impact sensor, it can be determined whether the line has been torn from the valve and / or whether the line has a crack. In the event of such damage, the valve can be activated to reduce the flow rate of the mixture from the container compared to a fully functional or undamaged line. This allows for a particularly slow release of the mixture from the container, ensuring that an undesirably high concentration of flammable refrigerant does not accumulate in the vicinity of the container.

[0016] In the event of a severe impact, the control unit can infer damage to the container from the signal of at least one impact sensor. For example, it can determine that the container has a crack or an opening. Further measures can then be taken to prevent the formation of an ignitable mixture in the vicinity of the container.

[0017] Furthermore, the container, designed like a safety box, ensures that when the air conditioning unit is installed in the vehicle, even in the event of damage to the vehicle, for example due to an accident, the refrigerant circuit is better protected than it would be without the container. This also facilitates the use of the flammable refrigerant in the refrigerant circuit.

[0018] In the operation of the refrigerant circuit, a particularly safe use of the flammable refrigerant can therefore be achieved. This is especially advantageous when it is important to prevent the use of, for example, a fluorinated alkyl compound, such as a compound from the group of perfluorinated and polyfluorinated alkyl compounds (PFAS), as a refrigerant in the circuit. Instead of such a fluorinated refrigerant, the flammable refrigerant can be used as a natural refrigerant in the circuit.

[0019] This is technically easier to implement than using the also naturally occurring refrigerant R744 (CO2). This is because a refrigerant circuit operating with R744 must be designed so that the components of the refrigerant circuit can withstand the very high pressures that occur during operation.

[0020] Such a design of the components of the refrigerant circuit for very high operating pressures is not necessary if a flammable refrigerant such as R290 (propane) is used in the refrigerant circuit.

[0021] This results in lower manufacturing and maintenance costs for both the refrigerant circuit than would be the case with the natural refrigerant R744. This is advantageous.

[0022] The provision of a substantially enclosed container, which surrounds the components of the refrigerant circuit through which the flammable refrigerant flows during operation, also allows for the use of a larger quantity of flammable refrigerant in the refrigerant circuit than would be possible without this protective container. Furthermore, when a larger quantity of refrigerant is used in the refrigerant circuit, the circuit advantageously exhibits greater cooling and heating performance.

[0023] The design of the container also allows for a particularly compact refrigerant circuit, enabling the integration of all components through which the flammable refrigerant flows. This is advantageous when using the air conditioning system in a motor vehicle, as it allows for a space-saving installation of the container and refrigerant circuit within the vehicle.

[0024] Furthermore, specifying a certain container size allows the amount of flammable refrigerant in the refrigerant circuit to be limited to an acceptable level. This is advantageous for the safe operation of the refrigerant circuit and the vehicle equipped with the air conditioning system.

[0025] Preferably, the evaporator is connected to both the refrigerant circuit and a first coolant circuit of the air conditioning system. Heat can be introduced into the refrigerant via the first coolant circuit. Furthermore, the refrigerant cooler is connected to both the refrigerant circuit and a second coolant circuit of the air conditioning system, allowing heat to be dissipated from the refrigerant via the second coolant circuit. These coolant circuits, designed as secondary circuits, advantageously allow the refrigerant reservoir to be positioned at a suitable distance from heat exchangers integrated into the respective coolant circuits. These heat exchangers allow heat to be introduced into and removed from the coolant. This facilitates a particularly safe installation of the refrigerant circuit within the vehicle.

[0026] For example, the first coolant circuit can be used to dissipate heat in the motor vehicle, such as for the purpose of cooling an airflow that can be introduced into a passenger compartment of the motor vehicle and / or for cooling, in particular, electrical components of the motor vehicle such as a high-voltage battery and / or an electric drive unit or the like.

[0027] In contrast, the second coolant circuit can be used to dissipate the heat transferred from the refrigerant to the coolant via a heat exchanger that can be exposed to ambient air. Such a heat exchanger can be located, particularly in the front of the vehicle, when the air conditioning system is installed. This is because such a front-end cooler is very easy to access and allows unobstructed exposure to ambient air to dissipate heat from the refrigerant.

[0028] Preferably, depending on the configuration of the refrigerant circuit, when the refrigerant circuit is used in a heat pump operation, heat from the ambient air and / or waste heat from vehicle components to be cooled can be introduced into the refrigerant flowing through one of the two refrigerant circuits. This heat can then be transferred back into the refrigerant circuit at the evaporator. The other of the two refrigerant circuits allows heat absorbed by the refrigerant and transferred to the refrigerant at the refrigerant cooler to be used for heating. For example, the heat can be used to condition, in particular, electrical components of the vehicle and / or to heat the passenger compartment of the vehicle.

[0029] In particular, the control device can ensure that the concentration of the flammable refrigerant in the air surrounding the container is kept below the lower ignition limit or lower explosion limit.

[0030] When the valve is closed, it advantageously ensures that the container is also sealed off from the environment. With this sealed design, the lines of the first and second coolant circuits can pass through the container walls. Coolant can flow through these lines, allowing heat to be transferred to or removed from the refrigerant via the coolant circuits.

[0031] At the points where the pipes or coolant lines pass through the container walls, the container is preferably reliably sealed. This can be achieved very easily. Accordingly, even in the area of ​​the penetrations or openings for the pipes, the container is preferably designed to be closed in such a way that if refrigerant escapes from the refrigerant circuit at the penetrations or openings, there is no uncontrolled release of refrigerant from the container into the environment.

[0032] The valve can be integrated directly into a wall of the container. Alternatively, it is possible to attach the valve to a connection port, which can be formed in or on a wall of the container.

[0033] Preferably, the valve is connected to a line, with the outlet opening of the line being located further away from the container than the inlet opening. In this way, any flammable refrigerant that has escaped from the refrigerant circuit in the event of a leak can be directed away from the container via the line to a suitable distance. This is particularly advantageous for achieving thorough dilution of the flammable refrigerant exiting the line with air or ambient air.

[0034] In particular, when the air conditioning system is installed in the vehicle, the outlet of the line can be located in the area of ​​a fan designed to supply air to a radiator of a coolant circuit within the air conditioning system. Operating the fan in this way allows for particularly good turbulence of the flammable refrigerant, resulting in a corresponding dilution of the refrigerant with the ambient air. This is advantageous.

[0035] It is advantageous if the line is designed as a hose. This makes it particularly easy to route the line so that the outlet opening is located in a position that allows for good dilution of the flammable refrigerant mixture with the ambient air.

[0036] Additionally, the control unit can be configured to evaluate a signal from a leakage sensor of the air conditioning system. In this case, the leakage sensor is designed to detect a leakage of refrigerant from the refrigerant circuit. This allows the control unit to advantageously actuate the valve selectively when refrigerant leaks from the refrigerant circuit into the container, i.e., when a leak occurs in the refrigerant circuit.

[0037] Preferably, the control device is designed to determine the amount of refrigerant entering the container from the refrigerant circuit based on the signal from the leakage sensor and to control the valve accordingly. This allows the control device to effectively implement a graduated leakage management system.

[0038] For example, if the leakage sensor detects that only a small amount of flammable refrigerant has escaped from the refrigerant circuit, a mixture containing the refrigerant can be released into the environment in a controlled manner via the valve, without any flammable mixture escaping from the container.

[0039] If, on the other hand, the signal from the leakage sensor indicates that an ignitable mixture has formed in the container, the amount of mixture drained from the container can be limited by adjusting the valve so that, upon exiting the container, a mixture is formed in the vicinity of the container in which the proportion of flammable refrigerant is below the lower ignition limit.

[0040] Such a metered release of the still flammable mixture from the container can be achieved by intermittently opening the valve if the valve is designed as a switching valve that can only be fully open or fully closed. If the valve is designed as a proportional valve with a variable flow-through outlet cross-section, the amount of mixture that can escape from the container into the environment can be precisely controlled by adjusting the valve's opening degree. In both cases, it is possible to achieve dilution of the flammable refrigerant in the vicinity of the container, resulting in a concentration below the lower flammability limit.

[0041] Preferably, at least one extinguishing agent reservoir is arranged inside the container and / or on an exterior surface of the container. The control device enables the release of an extinguishing agent from the reservoir. This effectively prevents the formation of an ignitable mixture in the vicinity of the container, even if the leakage of flammable refrigerant from the container becomes uncontrollable due to damage.

[0042] When the extinguishing agent reservoir is installed inside the container, the extinguishing agent released from it can take effect particularly quickly. In contrast, arranging the extinguishing agent reservoir on the outside of the container offers greater ease of maintenance. Both are advantageous.

[0043] The extinguishing agent can be, in particular, a medium that displaces oxygen and / or a medium that chemically and / or physically binds the flammable refrigerant in such a way that no ignitable mixture of flammable refrigerant and air is formed. For example, for the latter purpose, the extinguishing agent can be designed in the form of an extinguishing gel.

[0044] Finally, it has proven advantageous if an inner and / or outer surface of at least one wall of the container is provided with at least one coating, wherein the coating at least inhibits the generation of sparks upon impact of an object against the at least one wall. Such a coating facilitates the use of the flammable refrigerant in the refrigerant circuit. Even if flammable refrigerant escapes from the refrigerant circuit, the coating ensures that the formation of sparks, which could otherwise promote ignition of the flammable refrigerant, is made more difficult. For example, the coating can be made of a rubber material and / or a polymer.

[0045] Applying a coating to the outer surface of at least one wall prevents sparks from occurring due to collisions between objects and the wall's surface. Similarly, applying the coating to the inner surface of the wall advantageously prevents sparks from being generated, for example, by collisions between components of the refrigerant circuit and the wall's surface. Both are beneficial.

[0046] The motor vehicle according to the invention has an air conditioning device according to the invention. This simplifies the use of the flammable refrigerant in the refrigerant circuit in the motor vehicle.

[0047] Preferably, the air conditioning unit is located outside the passenger compartment of the vehicle. This prevents flammable refrigerant from entering the passenger compartment should it leak from the unit. This is advantageous in terms of ensuring a high level of safety for the occupants of the passenger compartment.

[0048] In particular, the container can be positioned in an area of ​​the vehicle protected from impact forces by the vehicle's body components. Such crash-resistant placement of the container within the vehicle can ensure that, in accidents involving only moderate deformation of the body components, the container remains undamaged. This is advantageous.

[0049] The advantages and preferred embodiments described for the air conditioning device according to the invention apply analogously to the motor vehicle according to the invention and vice versa.

[0050] The invention therefore also includes further developments of the motor vehicle according to the invention, which have features as already described in connection with the further developments of the air conditioning device according to the invention. For this reason, the corresponding further developments of the motor vehicle according to the invention are not described again here.

[0051] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus.

[0052] The invention also includes combinations of the features of the described embodiments. The invention therefore also includes realizations that each exhibit a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

[0053] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 highly schematically represents an air conditioning system for a motor vehicle in which a refrigerant circuit containing a flammable refrigerant is protected within a container or safety box; Fig. 2 a variant of the air conditioning system which includes a fire extinguishing agent reservoir; and Fig. 3 schematically a motor vehicle in which the container of the air conditioning unit is arranged between body components in the form of longitudinal beams of the motor vehicle.

[0054] The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0055] In the figures, identical reference symbols denote functionally equivalent elements.

[0056] In Fig. Figure 1 schematically shows an air conditioning unit 10 as it is used in a building. Fig. The air conditioning unit 10 can be used in the motor vehicle 12 shown in Figure 3. The air conditioning unit 10 comprises a refrigerant circuit 14 in which, during operation, a flammable refrigerant preferably circulates. During operation of the refrigerant circuit 14, a compressor 16 of the refrigerant circuit 14 pumps the flammable refrigerant to a refrigerant cooler 18. During operation of the refrigerant circuit 14, the refrigerant coming from the refrigerant cooler 18 is expanded by means of an expansion device 20, for example, in the form of an expansion valve. The expanded refrigerant is then supplied to an evaporator 22 of the refrigerant circuit 14.

[0057] The evaporator 22 is preferably designed as a chiller, which is integrated on one side into the refrigerant circuit 14 and on the other side into a first coolant circuit 24 of the air conditioning unit 10. The refrigerant evaporating in the evaporator 22 or chiller of the refrigerant circuit 14 can absorb heat from a coolant flowing through the first coolant circuit 24. One coolant side 26 of a heat exchanger provided by the evaporator 22 is in Fig. Figure 1 schematically indicates the process. The coolant flowing through the coolant side 26 of the first coolant circuit 24 can therefore introduce heat into the refrigerant during operation of the refrigerant circuit 14, which then evaporates in the evaporator 22. The evaporated refrigerant is then returned to the compressor 16 in the refrigerant circuit 14, which can be designed, in particular, as an electrically driven refrigerant compressor.

[0058] Preferably, the refrigerant cooler 18 is integrated analogously into the refrigerant circuit 14 on one side and into a second coolant circuit 28 of the air conditioning unit 10 on the other, wherein heat can be dissipated from the refrigerant via the second coolant circuit 28. One coolant side 30 of a heat exchanger comprising the refrigerant cooler 18 is in Fig. Figure 1 shows a schematic representation. The coolant, which flows through the second coolant circuit 28 and thus also the coolant side 30, can absorb heat from the compressed and heated refrigerant in the refrigerant cooler 18. The heat can then be dissipated via the second coolant circuit 28.

[0059] For example, the coolant flowing through the first coolant circuit 24 can be used to cool a passenger compartment 32 of the motor vehicle 12 (compare Fig. 3) and / or components of the motor vehicle 12 that need to be cooled. For example, the motor vehicle 12 may be designed as an electric vehicle or a hybrid vehicle. In this case, the coolant cooled by means of the evaporator 22 and flowing through the first coolant circuit 24 can be used to dissipate heat from an electrical energy storage device of the motor vehicle 12 and / or from at least one electric drive unit of the motor vehicle 12.

[0060] The coolant flowing through the second coolant circuit 28 can be supplied to a radiator (not shown), which is located particularly in the area of ​​a vehicle front 34 of the motor vehicle 12 (compare Fig. 3) can be arranged. On such a front-end cooler, a further heat exchanger (not shown), which is integrated into the second coolant circuit 28, can be supplied with ambient air in order to transfer the heat of the coolant, which originates from the refrigerant, to the ambient air.

[0061] When the refrigerant circuit 14 is used in heat pump operation, heat can be introduced into the coolant flowing through one of the coolant circuits 24, 28, for example, at the radiator (not shown) located in the area of ​​the vehicle front 34 and / or at components of the motor vehicle 12 to be cooled, in particular electrical components. This heat can then be used in turn to supply the passenger compartment 32 of the motor vehicle 12 with heated air in heat pump operation.

[0062] Out of Fig. 1 It is evident that the air conditioning device 10 comprises a container 36 in which those components of the refrigerant circuit 14 are protected and are exposed to the flammable refrigerant during operation of the refrigerant circuit 14.

[0063] According to Fig. For example, the compressor 16, the refrigerant cooler 18, the expansion device 20, and the evaporator 22 are arranged within the container 36, as are the refrigerant lines 38, which connect these components of the refrigerant circuit 14. Thus, those components of the refrigerant circuit 14 through which the flammable refrigerant flows during operation of the refrigerant circuit 14 are arranged within the container 36 and are thereby protected.

[0064] The container 36 is designed to be almost completely closed on its circumference. In the area of ​​coolant lines belonging to the coolant circuits 24, 28, the walls 40 of the container 36 have openings through which the coolant lines pass. In the area of ​​these openings, the walls 40 are preferably sealed so that the container 36 is also closed to the environment at these openings.

[0065] Furthermore, the container 36 preferably has at least one valve 42 which is designed to release refrigerant from the container 36 in the event of a leak in the refrigerant circuit 14. The air conditioning unit 10 comprises a Fig. 1. Schematically shown control device 44, approximately in the form of a control unit. The control device 44 is designed to control the valve 42.

[0066] By providing valve 42, a leakage management system can be implemented, which makes it possible to prevent a fire from starting in a variety of possible cases if flammable refrigerant escapes from the refrigerant circuit 14.

[0067] For example, the control unit 44 can enable a staged leakage management system, which makes the use of the flammable refrigerant R290 (propane) in the refrigerant circuit 14 particularly safe. The fundamental objective of the leakage management system is to keep the concentration of the flammable refrigerant in the ambient air below the lower ignition limit in the event of a refrigerant leak from the refrigerant circuit 14. To this end, in the event of a leak, the valve 42 can be opened to release a mixture of flammable refrigerant that has accumulated inside the container 36 into the surrounding area 46 of the container 36 in a controlled manner.

[0068] The valve 42 can have a fixed flow cross-section and thus be designed like a fixed throttle. Opening the valve 42 allows the mixture containing the flammable refrigerant to be released into the surroundings 46 of the container 36. In particular, a metered release of the mixture into the surroundings 46 of the container 36 can be achieved by alternately opening and closing the valve 42 if the valve 42 has a fixed flow cross-section.

[0069] Furthermore, the valve 42 can be designed, for example, as an electrically controlled valve 42, which has a variable opening width. Then, by adjusting the opening width of the valve 42 using the control device 44, it can be precisely determined what quantity or volume flow rate of the mixture located in the container 36 can escape into the environment 46.

[0070] According to Fig. 1. A line 48, in particular designed as a hose, can be connected to the valve 42. Here, an outlet opening 50 of the line 48 is located further away from the container 36 than an inlet opening of the line 48. This allows the mixture escaping from the container 36 in the event of a leak in the refrigerant circuit 14 to be directed to a location in the surroundings 46 where thorough mixing with the ambient air can take place.

[0071] For example, the outlet opening 50 can be located in the area of ​​the (not shown) radiator of the motor vehicle 12. Then, by operating a (not shown) fan associated with the radiator, particularly good mixing of the gas mixture with the ambient air can be achieved, thus diluting the flammable refrigerant.

[0072] In Fig. Figure 1 schematically shows a leakage sensor 52 of the air conditioning unit 10, wherein the control unit 44 is designed to evaluate signals from the leakage sensor 52. The leakage sensor 52 can preferably be used to determine the concentration of the flammable refrigerant within the container 36 if flammable refrigerant has leaked from the refrigerant circuit 14.

[0073] Furthermore, the control device 44 can preferably evaluate signals from at least one impact sensor 54 of the motor vehicle 12. This allows signals from impact sensors 54 already present in the motor vehicle 12, which may be designed, for example, as acceleration sensors and / or pressure sensors, to be used to detect the intensity of a potential impact of the motor vehicle 12. The intensity of the potential impact can preferably be taken into account in the leakage management system.

[0074] The leakage management implemented by the control unit 44 can trigger graduated responses, for example, depending on the severity of the leak. For instance, the leakage sensor 52 can detect that only a minor leak is present, meaning that only a relatively small amount of flammable refrigerant is escaping from the refrigerant circuit 14 into the interior of the container 36. If the amount of flammable refrigerant within the container 36 is correspondingly small, the mixture forming in the container 36 is not ignitable. In this case, by opening the valve 42, the mixture containing the air in the container 36 and the flammable refrigerant can be released or discharged in small, controlled quantities into the environment 46.

[0075] If the refrigerant is heavier than air, it collects in a lower area of ​​container 36 or the safety box. Then, as described in... Fig. Figure 1 shows that, with a valve 42 arranged in the area of ​​a lower wall 40 of the container 36, the mixture is slowly drained downwards from the container 36 by opening the valve 42.

[0076] If, on the other hand, the refrigerant is lighter than air, the refrigerant that has escaped from the refrigerant circuit 14 collects in the upper part of the container 36. In this case, the valve 42 can be operated differently than in Fig. 1 shown in or on an upper wall 40 of the container 36. The mixture contained in the container 36 can thus escape slowly upwards through the open valve 42 located at the top.

[0077] Furthermore, it may occur that the evaluation of the signal from the leakage sensor 52 indicates a serious leak. This can happen if an ignitable mixture forms in the container 36. In this case, the volume flow of the mixture released into the environment 46 via the valve 42, or via the valve 42 and the hose or line 48, can be limited so that dilution occurs in the environment 46 of the container 36 at which the lower ignition limit is undercut.

[0078] If the control device 44 additionally evaluates the signals of the at least one impact sensor 54, different intensities of an impact of the motor vehicle 12, i.e. different crash cases, can be distinguished in the leakage management.

[0079] For example, a minor crash or impact of the motor vehicle 12 may occur, resulting in no damage to the container 36 and / or the hose or line 48. In this case, as described above, leakage management can be implemented by differentiating between minor leakage, where no ignition occurs, and major leakage, where the mixture within the container 36 is ignitable.

[0080] If the control device 44 detects a medium-severe impact or crash of the motor vehicle 12 by evaluating the signal from the at least one impact sensor 54, damage to the line 48 or a corresponding drain hose may occur. In this case, the valve 42 can be throttled to ensure that the mixture is drained from the container 36 more slowly than would be the case with an undamaged line 48.

[0081] In another scenario, the evaluation of the signals from the impact sensor 54 can lead the control unit 44 to detect a severe impact or crash, which could result in damage to the container 36. For example, cracks or openings may form in at least one of the walls 40 of the container 36 if such a severe impact of the vehicle 12 occurs. In this case, there is an increased probability that the refrigerant circuit 14 will also be damaged, resulting in a leakage of refrigerant from the refrigerant circuit 14.

[0082] In particular, if the control device 44 concludes that, due to damage to the container 36, a controlled release of the mixture into the environment 46 via the control of the valve 42 cannot be achieved with sufficient reliability, further measures can be taken which relate to Fig. 2 will be explained.

[0083] At the in Fig. In the variant of the air conditioning unit 10 shown in Figure 2, the coolant circuits 24 and 28 are not shown for the sake of clarity. However, in Fig. Figure 2 schematically indicates an extinguishing agent storage unit 56 of the air conditioning unit 10. The extinguishing agent storage unit 56 contains an extinguishing agent which can be introduced into the container 36 and / or released into the environment 46 of the container 36.

[0084] The at least one extinguishing agent storage unit 56 can be used as in Fig. Figure 2 shows an example of the arrangement on the outside of the container 36. Additionally or alternatively, the at least one extinguishing agent reservoir 56 can be arranged inside the container 36.

[0085] Preferably, the control device 44 can cause the extinguishing agent to be dispensed from the extinguishing agent storage container 56. The extinguishing agent or extinguishing medium can, particularly in the event of a severe crash that results in damage to the container 36, chemically and / or physically bind the flammable refrigerant and / or displace oxygen, thus preventing ignition of the mixture.

[0086] In Fig. Figure 3 is a highly schematic representation of how the container 36 of the air conditioning unit 10 can be arranged in the motor vehicle 12 in a manner protected from impact forces in an accident. For example, the container 36 can be arranged in the area of ​​the front of the motor vehicle 12, in particular between a first longitudinal member 58 and a second longitudinal member 60 of the motor vehicle 12. From the schematic representation in the Fig. Figure 3 shows that even in the event of a frontal impact of the motor vehicle 12 on an obstacle (not shown) and a significant deformation of the longitudinal members 58, 60, damage to the container 36 is largely avoided.

[0087] Overall, the examples show how leakage management for a flammable refrigerant can be provided in a thermal management system in the form of the air conditioning unit 10.

Claims

[1] Air conditioning device (10) for a motor vehicle (12), comprising a refrigerant circuit (14) which includes a compressor (16) for conveying a flammable refrigerant to a refrigerant cooler (18) of the refrigerant circuit (14), wherein the refrigerant circuit (14) includes an expansion device (20) for expanding the refrigerant coming from the refrigerant cooler (18) and an evaporator (22) which can be supplied with the expanded refrigerant during operation of the refrigerant circuit (14), wherein the air conditioning device (10) comprises a container (36) in which those components of the refrigerant circuit (14) are protected which, during operation of the refrigerant circuit (14), are exposed to the flammable refrigerant, wherein the container (36) has a valve (42), wherein at least partial opening of the valve (42) can be effected by means of a control device (44) of the air conditioning device (10), wherein the valve (42) is designed to release refrigerant from the container (36) in the event of a leak in the refrigerant circuit (14), and wherein the control device (44) is designed to evaluate a signal from at least one impact sensor (54) of the motor vehicle (12), characterized by , that the control device (44) is designed to detect damage to a line (48) connected to the valve (42) and / or damage to the container (36) based on the signal from the at least one impact sensor (54) and to control the valve (42) depending on the damage. [2] Air conditioning device (10) according to claim 1, characterized by , that the evaporator (22) on the one hand into the refrigerant circuit (14) and on the other hand, is integrated into a first coolant circuit (24) of the air conditioning unit (10), wherein heat can be introduced into the refrigerant via the first coolant circuit (24), wherein the refrigerant cooler (18) is integrated on the one hand into the refrigerant circuit (14) and on the other hand into a second coolant circuit (28) of the air conditioning unit (10), and wherein heat can be removed from the refrigerant via the second coolant circuit (28). [3] Air conditioning device (10) according to any one of the preceding claims, characterized by , that the line (48), in particular designed as a hose, is connected to the valve (42), wherein an outlet opening (50) of the line (48) is further away from the container (36) than an inlet opening of the line (48). [4] Air conditioning device (10) according to any one of the preceding claims, characterized by , that the control device (44) is designed to evaluate a signal from a leakage sensor (52) of the air conditioning device (10), wherein the leakage sensor (52) is designed to detect a leakage of refrigerant from the refrigerant circuit (14). [5] Air conditioning device (10) according to claim 4, characterized by, that the control device (44) is designed to determine, based on the signal from the leakage sensor (52), the quantity of refrigerant entering the container (36) from the refrigerant circuit (14) and to control the valve (42) depending on the quantity. [6] Air conditioning device (10) according to any one of the preceding claims, characterized by , that at least one extinguishing agent storage unit (56) is arranged inside the container (36) and / or on an outside of the container (36), wherein the extinguishing agent can be dispensed from the extinguishing agent storage unit (56) by means of the control device (44). [7] Air conditioning device (10) according to any one of the preceding claims, characterized by, that an inner and / or an outer surface of at least one wall (40) of the container (36) is provided with at least one coating which, in the event of an impact of an object on the at least one wall (40), at least inhibits the generation of sparks. [8] Motor vehicle (12) with an air conditioning device (10) according to one of the preceding claims, wherein the container (36) of the air conditioning device (10) is arranged outside a passenger compartment (32) of the motor vehicle (12), in particular in an area of ​​the motor vehicle (12) protected from an accident-related force by body components (58, 60) of the motor vehicle (12).

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