DE102023208004A1 - Method for controlling radiator blinds or shutters - Google Patents

Abstract

In order to create a method (40) for controlling at least one air control surface (20) of a vehicle (100), in which the vehicle (100) has a heat pump system (10) with at least one first heat exchanger (11, 12) and with at least one second heat exchanger (13), wherein the at least one first heat exchanger (11, 12) is coupled to the second heat exchanger (13) via a coolant circuit, wherein the at least one first heat exchanger (11, 12) is positioned in a vehicle compartment (110) and, depending on an operating mode of the heat pump system (10), is designed to extract heat from an air flow (L) fed into the vehicle compartment (110) or to release heat to the air flow (L), wherein the air flow (L) fed into the vehicle compartment (110) is controlled by the at least one air control surface (20), by means of which a defrosting process of a Heat exchanger (11) can be at least delayed, it is proposed to determine an incipient icing of the at least one first heat exchanger (11) based on measurement data from at least one sensor (32, 33) and to control the at least one air control surface (20) to compensate for a pressure loss at the first heat exchanger (11) due to the icing.

Description

The invention relates to a method for controlling at least one air control surface of a vehicle, which has a heat pump system with at least one first heat exchanger and at least one second heat exchanger. The invention further relates to a heat pump system and a vehicle.

To improve aerodynamics and the associated reduction in fuel consumption and energy consumption, radiator blinds or shutters can be used in vehicles. Such air control surfaces reduce the area of the radiator grille through which the engine compartment can be reached. However, reducing the cross-section of the radiator grille also reduces the volume flow flowing into the engine compartment and thus also the cooling performance. At low ambient air temperatures, the ambient heat exchanger of the heat pump can frost up and ice up. Due to the icing of the ambient heat exchanger, a lower volume flow of air can pass through the ambient heat exchanger, which increases the air-side pressure loss of the ambient heat exchanger. Such processes reduce the efficiency of a heat pump or an air conditioning system that uses the ambient heat exchanger.

From the US 2023/0091458 A1 A cooling cycle device for a vehicle is known which comprises a heat exchanger which functions as a condenser when the air is cooled. In an alternative operation, the heat exchanger functions as an evaporator when the air in the vehicle cabin is heated.

In the EP 3 785 951 A1 A vehicle-mounted air conditioning unit is described which has a dehumidification function and can ensure stable dehumidification operation despite fluctuating heat load.

The US 2021/0276398 A1 describes a method for operating a heat pump in which a defrosting process is carried out when frost forms on an external heat exchanger. For this purpose, a flap for the grill opening is closed and a fan is rotated in the opposite direction during the defrosting process. As a result, the air heated by a radiator arranged next to the heat exchanger is blown into the external heat exchanger and the frost on the external heat exchanger is removed.

From the DE 10 2014 102 078 A1 A method for defrosting an ambient heat exchanger is known. The ambient heat exchanger is part of an air conditioning system for conditioning the air in the passenger compartment of a motor vehicle. To defrost the ambient heat exchanger, the air conditioning system's refrigerant circuit is switched to defrost mode and the supply air is conveyed in recirculation mode. Warm air from the engine compartment is circulated through air ducts to the ambient heat exchanger and the icy surface is defrosted.

During the defrosting process of an ambient heat exchanger, the heat pump or the air conditioning system is usually operated in an opposite flow direction of the refrigerant or is deactivated. This procedure can result in impairment of the comfort of the vehicle's passengers.

The invention is based on the object of creating a method and a heat pump system by means of which a defrosting process of a heat exchanger can at least be delayed. This object is achieved by the features specified in claim 1. Further advantageous embodiments of the invention are described in the subclaims.

According to one aspect of the invention, a method for controlling at least one air control surface of a vehicle is provided. The vehicle has a heat pump system with at least one first heat exchanger and with at least one second heat exchanger.

The at least one first heat exchanger can be designed, for example, as an ambient heat exchanger and the at least one second heat exchanger can be designed, for example, as an interior heat exchanger of the vehicle.

The at least one first heat exchanger is coupled to the second heat exchanger via a coolant circuit. Additional components such as expansion valves, pumps or compressors and the like can be provided for this purpose. The at least one first heat exchanger is positioned in a vehicle compartment and is designed, depending on an operating mode of the heat pump system, to extract heat from an air flow directed into the vehicle compartment or to release heat to the air flow directed into it.

The air flow directed into the vehicle compartment is controlled by the at least one air control surface. A volume flow and/or a flow velocity and/or an inflow angle of the air flow into the vehicle compartment can be controlled by the at least one air control surface. Depending on the design, controlling or regulating the air flow can mean completely releasing or opening an inlet opening or completely closing the inlet opening, so that the volume flow of the air flow fed into the vehicle compartment can be maximized or minimized. Accordingly, any gradations in terms of controlling and/or regulating the air flow can be set between the two extremes mentioned.

According to the invention, the onset of icing of the at least one first heat exchanger is determined based on measurement data from at least one sensor. After the icing of the first heat exchanger has been determined, the at least one air control surface is controlled to compensate for a pressure loss at the heat exchanger due to the icing. This measure can be implemented by increasing the volume flow and/or by increasing a flow speed or by varying an inflow angle into the vehicle compartment, in particular directed towards the first heat exchanger.

The method according to the invention enables de-icing measures to be delayed, whereby the de-icing measures can be carried out, for example, in a targeted manner in suitable situations, such as when standing still at a traffic light or at low driving speeds.

According to a further aspect of the invention, a heat pump system is provided which is designed to carry out a method according to the invention. The heat pump system also serves to control a volume flow and/or an inflow angle of at least one air flow into at least one vehicle compartment by means of air control surfaces. The vehicle compartment can be designed, for example, as an engine compartment. The heat pump system is at least partially arranged in the vehicle compartment and has at least one first heat exchanger and at least one interior heat exchanger, which are coupled to one another via a coolant circuit. The first heat exchanger can advantageously be thermally connected to an external environment of the vehicle. The second heat exchanger can, for example, be designed as an interior heat exchanger and, for example, be positioned in a passenger compartment of the vehicle.

The heat pump system can be used particularly efficiently in the vehicle sector if the air control surfaces are designed as at least one radiator shutter and/or as at least one radiator roller blind in order to adjust the volume flow and/or an inflow angle of the volume flow into the vehicle compartment.

According to a further aspect of the invention, a vehicle is provided which has a heat pump system according to the invention. In particular, the at least one first heat exchanger can be positioned in a vehicle compartment designed as an engine compartment, for example. Access for the air flow or air stream to the engine compartment can be provided via at least one opening, for example in the form of a radiator grille or in the area of the radiator grille. This access can be adjusted by the at least one air control surface. The inflow angle through the access and/or the inflow angle after passing through the access and/or a volume flow of the air stream can be adjusted by means of the at least one air control surface.

Access for the air flow or air stream to the vehicle compartment can be provided via at least one inflow opening, for example in the form of a radiator grille or in the form of an opening in the area of the radiator grille. This access can be adjusted by the at least one air control surface. The inflow angle through the access and/or the inflow angle after passing through the access and/or a volume flow of the air stream can be adjusted by means of the at least one air control surface.

The heat pump system according to the invention can be used, for example, to position radiator blinds or shutters depending on the refrigerant mass flow, even in a combination mode of the heat pump system. In the combination mode of the heat pump system, both the ambient air can be used as a heat source or heat sink by a first heat exchanger and other components in the vehicle compartment can be used as a heat source or heat sink for at least one further first heat exchanger. The first heat exchangers can be coupled to one another in parallel or in series through the refrigerant circuit. This means that several ambient heat exchangers can also be used.

The at least one air control surface can be controlled and/or regulated particularly efficiently if the measurement data from the at least one sensor are received and evaluated by a control unit.

According to a further embodiment, due to the onset of icing of the first heat exchanger, the cooling water in the vehicle compartment at the at least one air control surface encounters increased resistance when passing through the first heat exchanger. Ice or frost clogs the fins of the first heat exchanger and thus reduces the regular flow cross-section of the air flow. Advantageously, when the first heat exchanger begins to ice up, the at least one air control surface is opened or controlled in such a way that an air flow with a larger volume flow and/or with a higher flow velocity is directed to the first heat exchanger. The air-side resistance of air control surfaces, for example in the form of radiator blinds, in combination with the air-side resistance of the frost layer on the heat exchanger can significantly reduce the system efficiency of the heat pump. The above-mentioned measure can minimize the air-side resistance of air control surfaces in order to increase the system efficiency of the heat pump and also delay de-icing measures or postpone them for a period of time.

The onset of icing of the at least one first heat exchanger can be particularly simple from a technical perspective if it is determined based on a temperature difference between a surface of the heat exchanger and an environment. Characteristic curves for the possible temperatures can be created in advance and read out by the control unit when the heat pump system is in operation. For example, at an air temperature of 0°C, the first heat exchanger can have a temperature of -5°C without icing. As the degree of icing increases, it can be assumed that the temperature of the first heat exchanger will continue to drop because the heat pump system tries to compensate for the decreasing efficiency and increases the mass flow of the coolant. An increasing temperature difference can therefore be used as an indicator of icing. A threshold value for the temperature difference can be provided, from which the control unit initiates corresponding measures on the at least one air control surface in order to compensate for the pressure loss.

According to a further embodiment, the onset of icing of the heat exchanger is determined based on a measured or model-based determination of a frost load of the first heat exchanger. This measure makes it possible to take into account different boundary conditions of the first heat exchanger in order to determine the formation and increase or increase of icing. Boundary conditions such as air humidity, temperatures, vehicle speed, climate zone, time of day, season and the like can be taken into account when determining a frost load of the first heat exchanger.

The onset of icing in the first heat exchanger is technically particularly easy to determine by measuring the temperature below the dew point on the heat exchanger. Icing in the first heat exchanger can be detected during heating operation of the heat pump system if the refrigerant saturation pressure in the heat exchanger is below 0 °C and the dew point of the air or ambient air at the first heat exchanger is undershot.

According to a further embodiment, the onset of icing of the first heat exchanger is determined as a function of a relative humidity of the environment and/or an air temperature and/or a climate zone. This measure enables a particularly precise determination of environmental conditions that initiate icing of the first heat exchanger.

The onset of icing of the first heat exchanger can be determined particularly precisely from a technical perspective if it is determined based on a measured, in particular increasing, pressure loss at at least one first heat exchanger. For this purpose, pressure sensors can be provided which measure a pressure of the air flow in the inflow direction of the air flow before the at least one first heat exchanger and after the at least one first heat exchanger. The control unit can evaluate the measured data determined by the pressure sensors in order to determine an increasing reduction in pressure or an increase in pressure loss. This change can be used as an indicator of icing of the first heat exchanger.

• 1 eine schematische Darstellung eines erfindungsgemäßen Wärmepumpensystems gemäß einer Ausführungsform, und
• 2 ein schematisches Ablaufdiagramm zum Veranschaulichen eines erfindungsgemäßen Verfahrens gemäß einem Ausführungsbeispiel.

In the following, embodiments of the invention are explained in more detail with reference to the drawings. They show:

• 1 a schematic representation of a heat pump system according to the invention according to an embodiment, and
• 2 a schematic flow diagram to illustrate a method according to the invention according to an embodiment.

In the figures, the same structural elements have the same reference numerals.

The 1 shows a schematic representation of a heat pump system 10 according to the invention according to an embodiment. The heat pump system 10 serves to control a volume flow and/or an inflow angle E of at least one air flow L in at least one Vehicle compartment 110 by means of at least one air control surface 20 and is, for example, integrated into a vehicle 100.

In the exemplary embodiment shown, the vehicle compartment 110 is designed as an engine compartment. Furthermore, the air control surfaces 20 are designed as a radiator shutter, which can influence a volume flow of the air flow L and also the inflow angle E of the air flow L. The air control surfaces 20 can be controlled by means of an actuator 31, which can be controlled by a control unit 30.

The vehicle 100 is schematically designed as a hybrid vehicle and has an internal combustion engine 120 and a traction battery 130. An electric motor that can be fed with electrical energy by the traction battery 130 is not shown for the sake of clarity.

The heat pump system 10 is at least partially arranged in the vehicle compartment 110 and has a first heat exchanger 11, which is designed in the form of a first ambient heat exchanger, and a further first heat exchanger 12, which is designed as a second ambient heat exchanger. Furthermore, a second heat exchanger 13 is provided in the form of an interior heat exchanger.

The first ambient heat exchanger 11 and the second ambient heat exchanger 12 can function as evaporators and extract heat from an environment in order to heat a vehicle interior 140 via the interior heat exchanger 13. This operating state corresponds to a heating operation of the heat pump system 10. Analogously, the first ambient heat exchanger 11 and the second ambient heat exchanger 12 can function as condensers and conduct heat out of the vehicle interior 140 via the interior heat exchanger 13 and thus cool the vehicle interior 140. This operating state corresponds to a cooling operation of the heat pump system 10.

The first ambient heat exchanger 11 and the second ambient heat exchanger 12 are connected in parallel to one another and are also coupled to the interior heat exchanger 13 via a refrigerant circuit. For this purpose, the refrigerant circuit has a compressor 14 in order to be able to convey the refrigerant in a first direction or in a second direction. The heat pump system 10 can thus be operated in the heating mode for heating the interior heat exchanger 13 or in the cooling mode for cooling the interior heat exchanger 13.

Expansion valves are connected upstream of the ambient heat exchangers 11, 12, which can be controlled or regulated by the control unit 30 if required.

The heat pump system 10 is operated, for example, in a so-called combination mode. As a result, the first ambient heat exchanger 11 and the second ambient heat exchanger 12 are connected in parallel to one another, so that simultaneous heat absorption or heat release can be achieved. The first ambient heat exchanger 11 and the second ambient heat exchanger 12 are connected in parallel to one another by means of the refrigerant circuit, but do not necessarily have to be arranged adjacent to one another. Rather, the first ambient heat exchanger 11 can be arranged adjacent to the air control surfaces 20 and the second ambient heat exchanger 12 adjacent to the components 120, 130.

The first ambient heat exchanger 11 is designed to extract heat from the air flow L or to release it to the air flow L. The air flow L can in particular be a headwind. The second ambient heat exchanger 12 is designed to directly or indirectly release heat to at least one component 120, 130 or to extract it from the at least one component 120, 130. In the exemplary embodiment shown, the combustion engine 120 and the traction battery 130 are designed as possible components. The components 120, 130 are thermally coupled indirectly to the second ambient heat exchanger 12 via a coolant circuit or a water cooling system 15.

The at least one air control surface 20, which is designed as a radiator shutter, for example, can be controlled depending on a useful heat flow of the first ambient heat exchanger 11 and/or the second ambient heat exchanger 12 and/or a target output of the interior heat exchanger 13. Access of the air flow L to the engine compartment 110 is implemented schematically via an inflow opening 111, for example in the form of a radiator grille.

Furthermore, the heat pump system 10 has temperature sensors 32 and/or pressure sensors 33, which are connected to the control unit 30 in a data-conducting manner. For the sake of clarity, sensors that monitor the refrigerant circuit, the components 120, 130 and the interior 140 with regard to their properties are not shown.

Two temperature sensors 32 are shown schematically, which measure an ambient temperature and can determine a temperature of the first ambient heat exchanger 11 in order to detect, for example, icing of the first ambient heat exchanger 11 based on an evaluation of the measurement data of the temperature sensors 32 by the control unit 30.

Furthermore, two pressure sensors 33 are provided, which can determine measurement data of a pressure of the air flow L after passing the inlet opening 111 and a pressure of the air flow after passing the first ambient heat exchanger 11. The corresponding measurement data of the pressure sensors 33 are received and evaluated by the control unit 30 in order to determine a pressure loss at the first ambient heat exchanger 11. The pressure loss can be used as an indicator of frost or ice formation if a threshold value is exceeded.

In the 2 A schematic flow chart is shown to illustrate a method 40 according to the invention according to an embodiment. The method 40 serves to control at least one air control surface 20 of a vehicle 100 and is described with reference to the 1 The method 40 is not limited to heat pump systems 10 in combination mode and can generally be used in heat pump systems 10 which have a first ambient heat exchanger 11 and an interior heat exchanger 13. In this case, an air flow L is controlled on the first ambient heat exchanger 11 with the aid of at least one air control surface 20, such as a radiator roller blind or radiator shutter.

In a step 41, the air flow L fed into the vehicle compartment 110 is controlled by the at least one air control surface 20. For example, a volume flow and/or a flow velocity and/or an inflow angle E of the air flow L into the vehicle compartment 110 can be controlled and/or regulated by the at least one air control surface 20.

In a further step 42, measurement data from at least one sensor 32, 33 are received and evaluated by the control unit 30. By evaluating the measurement data, in a further step 43, an incipient icing of the at least one first heat exchanger 11 is determined. As the at least one first heat exchanger 11 icing up, the pressure loss at this heat exchanger 11 increases, since the layer of ice closes off the fins (not shown) of the first heat exchanger 11. The icing up of the first heat exchanger 11 can take place redundantly using the measurement data from the temperature sensors 32 and/or using the measurement data from the pressure sensors 33.

In a further step 44, the at least one air control surface 22 is controlled by the control unit 30 to compensate for a pressure loss at the first heat exchanger 11. In particular, the at least one actuator 31 is controlled by the control unit 30 in order to maximize or at least enlarge the cross section of the inflow opening 111.

list of reference symbols

100

vehicle

110

vehicle compartment / engine compartment

111

inlet opening

120

combustion engine / component

130

traction battery / component

140

vehicle interior

10

heat pump system

11

first ambient heat exchanger / first heat exchanger

12

second ambient heat exchanger / first heat exchanger

13

interior heat exchanger / second heat exchanger

14

compressor

15

Water cooling / Indirect thermal coupling

20

air control surfaces

30

control unit

31

actuator

32

temperature sensor

33

pressure sensor

40

Proceedings

41

Introducing an air flow into a vehicle compartment

42

Determination and evaluation of measurement data

43

Detecting icing

44

Control of air control surfaces

E

inflow angle of the air flow / airstream

L

airflow

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• US 2023/0091458 A1 [0003]
• EP 3 785 951 A1 [0004]
• US 2021/0276398 A1 [0005]
• DE 10 2014 102 078 A1 [0006]

Claims (10)

Method (40) for controlling at least one air control surface (20) of a vehicle (100), wherein the vehicle (100) has a heat pump system (10) with at least one first heat exchanger (11, 12) and with at least one second heat exchanger (13), wherein the at least one first heat exchanger (11, 12) is coupled to the second heat exchanger (13) via a coolant circuit, wherein the at least one first heat exchanger (11, 12) is positioned in a vehicle compartment (110) and, depending on an operating mode of the heat pump system (10), is designed to extract heat from an air flow (L) fed into the vehicle compartment (110) or to release heat to the air flow (L), wherein the air flow (L) fed into the vehicle compartment (110) is controlled by the at least one air control surface (20), characterized in that based on measurement data from at least one sensor (32, 33) an incipient icing of the at least one first heat exchanger (11) is determined and the at least one air control surface (20) is controlled to compensate for a pressure loss at the first heat exchanger (11) due to the icing. procedure according to claim 1 , wherein the measurement data from the at least one sensor (32, 33) are received and evaluated by a control unit (30). procedure according to claim 1 or 2 , wherein due to the onset of icing of the first heat exchanger (11), the air flow (L) guided into the vehicle compartment (110) past the at least one air control surface (20) has an increased resistance when passing through the at least one first heat exchanger (11), wherein the at least one air control surface (20) is opened or controlled in such a way that an air flow (L) with a larger volume flow and/or with a higher flow velocity is guided to the at least one first heat exchanger (11) when icing begins. Method according to one of the Claims 1 until 3 , wherein the onset of icing of the at least one first heat exchanger (11) is determined based on a temperature difference between a surface of the at least one first heat exchanger (11) and an environment. Method according to one of the Claims 1 until 4 , wherein the onset of icing of the at least one first heat exchanger (11) is determined based on a measured or model-based determination of a frost load of the at least one first heat exchanger (11). Method according to one of the Claims 1 until 5 , wherein the onset of icing of the first heat exchanger (11) is determined by means of a measured undershoot of the dew point at the first heat exchanger (11). Method according to one of the Claims 1 until 6 , wherein the onset of icing of the at least one first heat exchanger (11) is determined as a function of a relative humidity of the environment and/or an air temperature and/or a climate zone. Method according to one of the Claims 1 until 7 , wherein the onset of icing of the at least one first heat exchanger is determined on the basis of a measured, in particular increasing, pressure loss at the first heat exchanger. Heat pump system (10) which is adapted to carry out a method (40) according to one of the preceding claims. Vehicle (100) comprising a heat pump system (10) according to claim 9 .

Images