阅读说明：本技术 用于对机动车的热交换器除冰的方法和机动车 (Method for deicing a heat exchanger of a motor vehicle and motor vehicle ) 是由 J.韦斯索泽 J-C.阿尔布雷赫特 于 2021-06-08 设计创作，主要内容包括：为了提供一种用于对机动车的热交换器除冰的方法,通过该方法防止来自解冻过程的大量的融冰水流到机动车下方的地面或道路上、重新结冰并且造成行人受伤的危险,在用于对机动车(10)的热交换器(13)除冰的方法(100)中,针对布置在机动车(10)中的热交换器(13),实施用于去除形成在热交换器(13)的表面(14)上的冻结水层(20)或霜层的解冻过程,其中,该解冻过程包括对所述表面(14)的加热,在该解冻过程中产生融冰水(22),在该方法(100)中建议,将排出到机动车(10)下方的地面(24)的局部区域(23)上的融冰水(22)的量限制为最大值。(In order to provide a method for deicing a heat exchanger of a motor vehicle, by means of which method a large amount of ice-melting water from a defrosting process is prevented from flowing onto the ground or the road below the motor vehicle, re-icing and causing the risk of injury to pedestrians, in a method (100) for deicing a heat exchanger (13) of a motor vehicle (10), a defrosting process for removing a frozen water layer (20) or a frost layer formed on a surface (14) of the heat exchanger (13) is carried out for the heat exchanger (13) arranged in the motor vehicle (10), wherein the defrosting process comprises heating of the surface (14), during which defrosting process ice-melting water (22) is produced, it is proposed in the method (100) that the amount of ice-melting water (22) that is discharged onto a local area (23) of the ground (24) below the motor vehicle (10) is limited to a maximum value.)

1. Method (100) for deicing a heat exchanger (13) of a motor vehicle (10), wherein, for a heat exchanger (13) arranged in the motor vehicle (10), a defrosting process for removing a frozen water layer (20) or a frost layer formed on a surface (14) of the heat exchanger (13) is carried out, wherein the defrosting process comprises heating of the surface (14), wherein defrosting water (22) is produced, characterized in that the amount of defrosting water (22) that is discharged onto a local area (23) of a ground surface (24) below the motor vehicle (10) is limited to a maximum.

2. Method (100) according to claim 1, characterized in that the maximum value is less than the total amount of thawing water (22) produced during thawing, wherein the maximum value is preferably less than 50%, more preferably 10%, very particularly preferably 5% of the total amount of thawing water (22) produced during thawing.

3. Method (100) according to claim 1 or 2, wherein the maximum value is less than 10cl, preferably less than 5cl, particularly preferably less than 1cl, very particularly preferably less than 5ml, and/or the amount of ice-melting water (22) per unit area that is discharged onto a local area (23) of the ground (24) under the motor vehicle (10) is limited to a maximum value, wherein the maximum value is less than 10l/m²Preferably less than 5l/m²Particularly preferably less than 1l/m²Very particularly preferably less than 0.5l/m²Particularly preferably less than 0.1l/m²。

4. Method (100) according to any one of the preceding claims, characterized in that the thawing process is carried out only during driving of the motor vehicle (10).

5. Method (100) according to any one of the preceding claims, characterized in that the thawing water (22) produced during the thawing process is preferably evenly dispersed on the travel path, in particular on the ground (24).

6. Method (100) according to any one of the preceding claims, characterized in that during the implementation of the defrosting process a shutter element (27), in particular a shutter or a roller blind (27a), is arranged in front of the heat exchanger (13) in order to prevent the heat exchanger (13) from being crossed by ambient air, and/or the defrosting process is implemented only before the motor vehicle (10) reaches a maximum speed of 50km/h, preferably 25km/h, in particular 15km/h, very particularly preferably 10 km/h.

7. Method (100) according to any one of the preceding claims, characterized in that the thawing water (22) is collected in a collection container (25).

8. Method (100) according to claim 7, characterized in that the collecting container (25) comprises an outlet device (26), wherein the outlet device (26) preferably limits the amount of ice-melt water (22) discharged onto the localized area (23) and/or onto the ground (24) per unit area and/or from the collecting container (25) per unit time, and/or opens and/or closes the outlet device (26) in order to limit the amount of ice-melt water (22) discharged onto the localized area (23) and/or onto the ground (24) per unit area and/or from the collecting container (25) per unit time to the maximum value.

9. The method (100) according to any one of the preceding claims, wherein the thawing water (22) is evaporated.

10. A motor vehicle (10) having a heat exchanger (13) and a control unit (21), wherein the control unit (21) is designed to carry out the method (100) according to any one of claims 1 to 9.

Technical Field

The invention relates to a method for deicing a heat exchanger of a motor vehicle, wherein a defrosting process for removing a frozen water or frost layer formed on a surface of the heat exchanger is carried out for the heat exchanger arranged in the motor vehicle, wherein the defrosting process comprises heating of the surface, wherein defrosting water is produced in the defrosting process. The invention also relates to a motor vehicle having a heat exchanger and a control unit for carrying out the method for deicing the heat exchanger.

Background

Air conditioning devices or systems are used in various technical fields. Air conditioning devices or air conditioning systems with heat pumps are used in particular in electric vehicles. The use of an air conditioning device with a heat pump in an electric vehicle is advantageous, since in an electric vehicle no waste heat of the internal combustion engine is available for heating the passenger compartment. Instead, the heat required for heating is obtained from the outside air by means of a heat pump and delivered to the passenger compartment. For this reason, the heat exchanger of the heat pump, which is in contact with the outside air, must be cooled to a temperature lower than the ambient temperature of the outside air.

If the outside air falls below its dew point when the heat exchanger cools, a layer of frozen water, in particular frost or ice, forms on the surface of the heat exchanger. Thus, the frozen water layer hinders the flow of the outside air through the heat exchanger, and the efficient operation of the heat pump is no longer ensured. In order to enable the heat exchanger to be flowed through again by the outside air, a defrosting process of heating the heat exchanger is carried out in the prior art. By heating the heat exchanger, the frozen water layer melts and the outside air can flow through the heat exchanger again.

DE 102014218378 a1 discloses an air-cooled heat exchanger for cooling a fluid which can flow through the heat exchanger, which has a heat transfer block with a plurality of flow channels. The heat exchanger has a first collection tank and a second collection tank, wherein the collection tanks are fluidically connected to one another by flow channels. The heat transfer block may be flowed through by gas from the outside. Therefore, heat transfer between the fluid flowing in the flow passage and the gas flowing outside can be achieved by the heat exchanger.

DE 102017115190 a1 discloses a device for deicing a heat exchanger in a motor vehicle. The device generally comprises an air guide housing for the passage of ambient air, having an inlet and an outlet adapted to communicate with the external environment of the motor vehicle. The device further comprises at least one fan and a first heat exchanger to be occasionally de-iced, which is arranged between the inlet and the outlet, wherein the first heat exchanger is operable in an operating mode in which the passing ambient air is cooled. It is provided that the inlet and the outlet can be closed, and that the at least one fan and the first heat exchanger are arranged in the air-conveying housing in such a way that at least one circulation path can be generated with the inlet and the outlet closed.

Patent document DE 112011101957T 5 discloses a heat pump cycle in which a refrigerant pipe of an exterior heat exchanger serving as an evaporator that evaporates refrigerant and a cooling fluid pipe of a radiator for dissipating heat of coolant of an electric motor serving as an external heat source are connected to the same exterior fin. In the defrosting operation including deicing the heat exchanger by flowing the coolant through the radiator, it is possible to suppress loss in the process of transferring heat contained in the coolant to the heat exchanger, and it is possible to effectively use heat supplied from the motor to deice the external heat exchanger.

DE 102015215955 a1 discloses an air conditioning system for a motor vehicle and a method for operating the same. The defrosting process is initiated primarily when the evaporator is only slightly flowed through by cold outside air, i.e. in particular at low driving speeds, for example below a predetermined limit speed.

A heat exchanger, in particular an evaporator, is known from DE 102007062512 a1, which has at least one collecting tank, a plurality of tubes which open into or emerge from the collecting tank, and a heat exchanger network which is formed from these tubes together with elements which enlarge the heat transfer surface, wherein a gap is provided between the elements which enlarge the heat transfer surface and the collecting tank, and a baffle is attached to at least one side of the heat exchanger at the level of the gap which is formed between the elements which enlarge the heat transfer surface and the collecting tank.

During the defrosting of the heat exchanger, a large amount of ice-melting water may be produced, which may flow onto the ground under the vehicle, in particular onto the road, and refreeze. A new layer of ice on the ground may for example cause the pedestrian to slip and be injured.

Disclosure of Invention

The object of the invention is therefore to provide a method for deicing a heat exchanger of a motor vehicle, by means of which a large amount of ice-melting water from the defrosting process is prevented from flowing onto the ground or the road underneath the motor vehicle, from re-icing and from causing the risk of injury to pedestrians.

In order to solve the above-described problem, a method for deicing a heat exchanger of a motor vehicle is proposed, wherein a defrosting process for removing a frozen water layer or a frost layer formed on a surface of the heat exchanger is carried out for the heat exchanger arranged in the motor vehicle, wherein the defrosting process comprises heating of the surface, during which defrosting process thawing water is produced, wherein provision is also made for the amount of thawing water discharged onto a partial region of the ground surface below the motor vehicle to be limited to a maximum value.

The motor vehicle can be designed as an electric vehicle, a battery electric vehicle or a hybrid electric vehicle.

The heat exchanger of the motor vehicle may be a heat pump and/or an air conditioning system of the motor vehicle or a part of the air conditioning system. The heat exchanger is preferably an external air heat exchanger and is designed in particular to transfer thermal energy from the external environment to a cooling fluid, in particular a coolant or refrigerant. The absorbed thermal energy may be used to heat a passenger compartment of the motor vehicle.

A surface of a heat exchanger is to be understood to mean, in particular, a surface of the heat exchanger which is in contact with the outside environment, wherein preferably the outside air from which the thermal energy is to be extracted flows through this surface.

The terms "frost", "frost layer", "ice" or "ice layer" or other correspondingly suitable terms may also be used for the frozen water layer formed on the surface of the heat exchanger.

Methods for identifying frozen water layers formed on the surface of a heat exchanger of a motor vehicle are known to those skilled in the art.

The thawing process may be a thawing cycle.

According to the invention, it is provided that, in the method, the amount of ice-melting water that is discharged onto a local region of the ground below the motor vehicle is limited to a maximum value.

By limiting the amount of ice-melt water that drains onto a localized area of the ground beneath the motor vehicle to a maximum value, a greater localized accumulation of ice-melt water on the ground is prevented, so that a larger ice surface is not locally formed on the ground due to refreezing of the ice-melt water. Thus reducing the risk of the pedestrian slipping or being injured.

The ground surface is preferably a part of a road or a sidewalk.

"local area" is understood to mean a spatially restricted area of the ground under the motor vehicle. For example, in the case of a stationary motor vehicle, the local region may be a restricted area at the location of the vehicle. The local region may have a thickness of less than or equal to 1m²Preferably less than or equal to 0.5m²Particularly preferably less than or equal to 0.1m²Very particularly preferably less than or equal to 0.01m²The area of (a). The localized region can also have a thickness of greater than or equal to 0.001m²Preferably greater than or equal to 0.005m²Particularly preferably 0.01m or more²The area of (a). In particular, the local region may have a surface that is at risk of slipping for pedestrians in the event of icing.

Preferably, it can be provided that the method is carried out, in particular, only when the motor vehicle is located in an urban area. Since pedestrians are less frequent on roads than in urban areas, especially in rural areas or rural roads, there is less risk that frozen ice-melting water poses a hazard there.

It can also advantageously be provided that the maximum value is less than the total amount of ice and water produced during the thawing process, wherein the maximum value is preferably less than 50%, more preferably less than 10%, and very particularly preferably less than 5% of the total amount of ice and water produced during the thawing process.

If, for example, 100ml of ice-melting water accumulates during the thawing process, it can be provided according to the method that the amount of ice-melting water discharged onto a partial region of the ground under the motor vehicle is less than 50ml, more preferably less than 10ml, particularly preferably less than 5 ml.

It can therefore preferably be provided that the maximum is less than 10cl, preferably less than 5cl, particularly preferably less than 1cl, very particularly preferably less than 5 ml.

Preferably, the amount of ice-melting water per unit area that is discharged onto a local area of the ground under the motor vehicle can be limited to a maximum value.

It can therefore be provided in particular that this maximum is less than 10l/m²Preferably less than 5l/m²Particularly preferably less than 1l/m²Very particularly preferably less than 0.5l/m²Particularly preferably less than 0.1l/m²。

It can further be advantageously provided that the thawing process is carried out only during the travel of the motor vehicle.

By carrying out the thawing process only during the travel of the motor vehicle, the ice-melting water is discharged onto the ground in a dispersed manner on the route traveled during the travel. Since the ice-melt water is dispersed over a large surface, the amount of ice-melt water discharged onto a local area of the ground is limited.

It is therefore preferably provided that the ice-melting water produced during the thawing process is preferably distributed uniformly over the route of travel, in particular on the ground.

It can further advantageously be provided that, during the defrosting process, a shielding element, in particular a shutter or a roller blind, is arranged in front of the heat exchanger in order to prevent the heat exchanger from being flowed through by ambient air.

By arranging the shielding element in front of the heat exchanger, the air flow through the heat exchanger, in particular the external or ambient air of the surface, is reduced or prevented, so that an efficient de-icing can be performed. In particular, by arranging a shielding element such as a louver or a roller shutter in front of the heat exchanger, the thawing process can be carried out even if the vehicle speed is large, so that the thawing ice produced during the thawing process is dispersed over a large area of the ground.

Alternatively or additionally, it can be provided that the thawing process is carried out only before the motor vehicle has reached a maximum speed of 50km/h, preferably 25km/h, particularly preferably 15km/h, very particularly preferably 10 km/h.

By limiting the maximum speed at which the defrosting process can be carried out, the method can also be carried out without arranging a shielding element in front of the heat exchanger. Since the air flow through the heat exchanger is limited or reduced by the speed limit of the vehicle, efficient de-icing can be performed.

Furthermore, it can be preferably provided that the ice-melting water is collected in a collection container.

By collecting the ice-melt water in a collection container, the ice-melt water is prevented from reaching the ground under the vehicle, especially on a local area.

It may further advantageously be provided that said collecting container comprises an outlet means, wherein the outlet means preferably limits the amount of ice-melting water discharged onto said localized area and/or onto the ground per unit area and/or from the collecting container per unit time, and/or opens and/or closes the outlet means so as to limit the amount of ice-melting water discharged onto said localized area and/or onto the ground per unit area and/or from the collecting container per unit time to said maximum value.

The limitation of the amount of ice-melting water can be achieved, for example, by the outlet means being a hole or opening with such a small diameter that the ice-melting water can only flow out of the collecting container in droplets.

However, it can also be provided that the outlet device is a valve which can be opened or closed, for example, by an electrical actuator. In particular, it can be provided that the outlet device is opened only when the motor vehicle is moving.

It is further advantageously provided that the ice-melting water is evaporated. The evaporation of the ice-melt water can be achieved, for example, in such a way that the ice-melt water is dripped onto the compressor housing of the compressor of the heat pump comprising the heat exchanger.

The evaporation of the ice melt water can effectively reduce or prevent the ice melt water from dripping onto the ground below the motor vehicle, so that in particular the amount of ice melt water discharged onto a local region of the ground below the motor vehicle is also limited to a maximum.

A further solution to the technical problem on which the invention is based consists in a motor vehicle having a heat exchanger and a control unit, wherein the control unit is designed to carry out the method described above.

The control unit is designed in particular to determine that icing of the heat exchanger has occurred and to initiate the defrosting process. The control unit may also be designed for opening or closing a valve of the collecting container, for example.

All the features, devices and functions described for the aforementioned method can also be transferred in a similar manner to the motor vehicle.

Drawings

The method is explained in more detail below with reference to the figures.

Fig. 1 shows a schematic view of a motor vehicle with a heat pump comprising a heat exchanger.

Detailed Description

Fig. 1 illustrates a method 100 for deicing a heat exchanger 13 of a motor vehicle 10. The figure shows a motor vehicle 10 with an air conditioning device 11 in a purely schematic view. The air conditioning system 11 has a heat pump 12 with a heat exchanger 13. The heat exchanger 13 is an outside air heat exchanger 13 a. Here, the outside air or the ambient air may flow over the surface 14 of the heat exchanger 13, so that thermal energy may be transferred to the refrigerant flowing through the heat exchanger 13. In the heat pump 12, the heat exchanger 13 serves as an evaporator 15. The heat pump 12 also has a condenser 16 for releasing thermal energy from the refrigerant into the passenger compartment of the motor vehicle 10, a compressor 17 and a throttle 18, and a refrigerant line 19. At lower external temperatures, a frozen water layer 20 may form on the surface 14 of the heat exchanger 13. The defrosting process is initiated if the control unit 21 of the air conditioning device 11 determines that the frozen water layer 20 blocks the flow of outside air through the heat exchanger 13 and thus efficient operation of the heat pump 12 is no longer ensured.

During this thawing process the surface 14 is heated, thereby creating ice-melt water 22. According to the method, the amount of ice melt water 22 that is discharged to a localized area 23 of the ground 24 beneath the motor vehicle 10 is then limited to a maximum value.

For example, as shown in fig. 1, a collection container 25 may be provided, and the ice-melt water 22 may be collected in the collection container. The collecting container 25 has an outlet device 26 designed as a valve 26 a. The control unit 21 may be designed to open the valve 26a only when the vehicle 10 is moving, thereby limiting the amount of ice-melt water 22 that drains to a localized area 23 of the ground 24 beneath the vehicle 10 to a maximum value. In order to be able to carry out the thawing process also when the motor vehicle 10 is in motion, a shielding element 27 in the form of a roller blind 27a can be provided, which is arranged in front of the heat exchanger 13 in such a way that ambient air is prevented from flowing through the heat exchanger 13.

Alternatively or additionally, it can be provided that at least a part of the ice-melt water 22 drips onto the compressor housing 28 of the compressor 17 of the heat pump 12, so that the ice-melt water 22 evaporates and does not reach the ground 24 below the motor vehicle 10 in liquid form.

List of reference numerals

100 method

10 Motor vehicle

11 air conditioner

12 heat pump

13 heat exchanger

13a outside air heat exchanger

14 surface of

15 evaporator

16 condenser

17 compressor

18 throttle valve

19 refrigerant line

20 frozen water layer

21 control unit

22 melting ice water

23 local area

24 ground

25 collecting container

26 outlet device

26a valve

27 Shielding element

27a roller shutter

28 compressor housing