阅读说明：本技术 用于运行车辆的制冷设施的方法以及制冷设施 (Method for operating a refrigeration system of a vehicle and refrigeration system ) 是由 D·施罗德 H·罗腾科尔布 于 2019-09-03 设计创作，主要内容包括：本发明涉及一种用于运行车辆的制冷设施(10)的方法,所述制冷设施包括具有热交换器(2)的制冷剂循环回路(1),其中,借助于可控制的环境空气流(L)流过热交换器(2)并且该热交换器能作为用于制冷设施-运行的制冷剂冷凝器或气体冷却器运行。根据本发明提出,为了在制冷剂循环回路(1)的高压和低压之间调节预设的压力比,借助于一种设备(7)根据车辆的环境温度的温度限值控制环境空气流(L)的流过热交换器(2)的空气量,其中,在高于温度限值的情况下借助于所述设备(7)提高流过热交换器(2)的空气量,和在环境温度最高相当于温度限值的情况下借助于所述设备(7)降低流过热交换器(2)的空气量。一个另选的解决方案提出,代替环境温度的温度限值应用在制冷剂循环回路(1)的高压和低压之间的压差的压差限值。本发明还涉及一种用于实施根据本发明的方法的制冷设施。(The invention relates to a method for operating a refrigeration system (10) of a vehicle, comprising a refrigerant circuit (1) having a heat exchanger (2), wherein a controllable ambient air flow (L) flows through the heat exchanger (2) and the heat exchanger can be operated as a refrigerant condenser or gas cooler for the operation of the refrigeration system. According to the invention, in order to set a predetermined pressure ratio between a high pressure and a low pressure of the refrigerant circuit (1), the air quantity of the ambient air flow (L) flowing through the heat exchanger (2) is controlled by means of a device (7) as a function of a temperature limit value of the ambient temperature of the vehicle, wherein the air quantity flowing through the heat exchanger (2) is increased by means of the device (7) above the temperature limit value and the air quantity flowing through the heat exchanger (2) is reduced by means of the device (7) if the ambient temperature corresponds at most to the temperature limit value. An alternative solution provides that instead of the temperature limit of the ambient temperature a pressure difference limit of the pressure difference between the high pressure and the low pressure of the refrigerant circuit (1) is applied. The invention also relates to a refrigeration plant for carrying out the method according to the invention.)

1. A method for operating a refrigeration system (10) of a vehicle, comprising a refrigerant circuit (1) having a heat exchanger (2), wherein a controllable ambient air flow (L) flows through the heat exchanger (2) and the heat exchanger can be operated as a refrigerant condenser or as a gas cooler for the refrigeration system operation,

it is characterized in that the preparation method is characterized in that,

-controlling the amount of air of the ambient air flow (L) flowing through the heat exchanger (2) by means of the device (7) as a function of a temperature limit of the ambient temperature of the vehicle, in order to adjust a preset pressure ratio between a high pressure and a low pressure of the refrigerant circuit (1),

-increasing the amount of air flowing through the heat exchanger (2) by means of said device (7) above a temperature limit, and

-reducing the amount of air flowing through the heat exchanger (2) by means of the device (7) in the case of an ambient temperature corresponding at most to a temperature limit value.

2. A method for operating a refrigeration system (10) of a vehicle, comprising a refrigerant circuit (1) having a heat exchanger (2), wherein a controllable ambient air flow (7) flows through the heat exchanger (2) and the heat exchanger can be operated as a refrigerant condenser or gas cooler for the refrigeration system operation,

it is characterized in that the preparation method is characterized in that,

-controlling the amount of air of the ambient air flow (L) flowing through the heat exchanger (2) by means of the device (7) as a function of a pressure difference limit of the pressure difference between the high pressure and the low pressure of the refrigerant circuit (1), wherein,

-increasing the amount of air flowing through the heat exchanger (2) by means of said device (7) in case the pressure difference is higher than the pressure difference value, and

-reducing the amount of air flowing through the heat exchanger by means of said device (7) in the case of a pressure difference lower than or equal to a pressure difference limit between the high pressure and the low pressure of the refrigerant circuit (1).

3. Method according to claim 1 or 2, characterized in that the device (7) is designed as a controllable air inlet (7.0, 7.1, 7.2).

4. A method according to claim 3, characterised in that the air inlet device (7.0, 7.1, 7.2) is designed with a plurality of pivotable dampers (7.01, 7.11, 7.21) which can be pivoted individually, jointly or in groups between an open position and a closed position.

5. Method according to any of the preceding claims, characterized in that the cooling air flow (L1) from the ambient air flow (L) having a cross section comparable to the maximum cooling surface of the heat exchanger (2) is adjusted by means of a device (7).

6. Method according to one of the preceding claims, characterized in that the plant (7) is designed with at least two sub-plants (7.1, 7.2), wherein the sub-plants (7.1, 7.2) correspond to mutually non-intersecting cooling surfaces (A1, A2) of the heat exchanger (2) in such a way that the partial cooling air streams (L11, L12) generated by the sub-plants (7.1, 7.2) from the ambient air stream (L) load the cooling surfaces (A1, A2) of the heat exchanger (2) corresponding to the partial cooling air streams.

7. Refrigeration plant (10) for a vehicle, comprising a refrigerant circulation circuit (1) with a heat exchanger (2), wherein,

-the heat exchanger (2) can be operated as a refrigerant condenser or as a gas cooler for refrigeration plant operation for carrying out the method according to one of the preceding claims,

-through which a controllable flow (L) of ambient air can flow the heat exchanger (2),

-in order to generate a controllable ambient air flow (L), the heat exchanger (2) is provided with a device (7) which influences the amount of air flowing through the heat exchanger (2), and

-the refrigerant circulation circuit (1) has, in addition to the heat exchanger (2), a refrigerant compressor (3) and an evaporator (4) with a fitted expansion valve (4.0).

8. Refrigeration plant (10) of claim 7,

it is characterized in that the preparation method is characterized in that,

the device (7) is designed as a controllable air inlet device (7.0),

-the air inlet device (7.0) has a plurality of pivotable dampers (7.01) which can be pivoted individually, jointly or in groups between an open position and a closed position.

9. Refrigeration plant (10) according to claim 7 or 8, characterized in that the device (7) is designed for conditioning a cooling air flow (L1) from the ambient air flow (L) having a cross section comparable to the maximum cooling surface of the heat exchanger (2).

10. Refrigeration plant (10) of any of claims 7 to 9,

it is characterized in that the preparation method is characterized in that,

-the device (7) is designed with at least two sub-devices (7.1, 7.2) such that the sub-devices (7.1, 7.2) correspond to mutually non-intersecting cooling surfaces (a1, a2) of the heat exchanger (2), the partial cooling air streams (L11, L12) generated by the sub-devices (7.1, 7.2) from the ambient air stream (L) loading the cooling surfaces of the heat exchanger corresponding to the partial cooling air streams.

Technical Field

The invention relates to a method for operating a refrigeration system of a vehicle, comprising a refrigerant circuit with a heat exchanger, according to the preamble of claim 1 and the preamble of claim 2.

Background

Such a method for operating a refrigeration system of a vehicle with a heat exchanger is known from EP 2072296B 1, in which, for cooling an electrical energy store of the vehicle, an air flow flows through an external condenser in thermal contact with the energy store, which serves as an air-refrigerant heat exchanger of a refrigerant circuit. The air flow through the condenser is selectively regulated by means of a regulating valve. In operation at low ambient temperatures, the cold ambient air through-flow condenser can therefore be reduced, as a result of which the temperature level of the refrigerant in the condenser rises. The regulating valve can be designed such that it at least partially covers the surface of the condenser through which air can flow. By exposing or closing this surface, the amount of air flowing through the condenser can be selectively varied, whereby an increase in the temperature level is achieved. The regulating valve can be designed in the form of a selectively adjustable shutter with which at least a part of the condenser surface for the through-flow of air can be closed.

It is known to equip motor vehicles at the front with an adjustable damper device in the form of a cooler grille, with which the cooling air of the cooler package can be controlled as a function of the position of the damper. Such a cooler package comprises, in addition to the air-refrigerant heat exchanger of the refrigerant circuit of the refrigeration system, other heat exchangers, such as a cryocooler, a charge air cooler, and possibly also a cooler in a vehicle having an internal combustion engine.

Such damper devices typically have a plurality of dampers that can be opened or closed as desired.

A refrigerant circuit is known from document EP 2360440 a1, comprising: a main circulation loop formed by a refrigerant compressor, a condenser and an evaporator with a matched expansion valve; and a secondary circulation circuit having a refrigerant compressor and at least one heat exchanger. The heat exchanger unit of the main circuit comprises an evaporator and a supercooling heat exchanger as well as an air flow control device with baffles or louvers, by means of which the air flow through the heat exchanger is as uniform as possible. In order to defrost the lower evaporator half, the air flow is guided only through the upper evaporator half, whereas in order to defrost the upper evaporator half, the air flow is guided only through the lower evaporator half.

In pure refrigeration system operation (also referred to as AC operation), the following problems can occur, in particular in the case of low ambient temperatures of the vehicle: the refrigeration installation does not start to operate, that is to say the static pressure level of the system has already been adjusted to the target low pressure level of the operation of the installation, or a steady continuous operation is not set, that is to say the high pressure in the system drops so far that it approaches the low pressure because of the low ambient temperature that the compressor cannot ensure a steady continuous pressure difference between the low pressure side and the high pressure side. This means that the high pressure level obtained is so low that no significant pressure ratio can be produced between the low-pressure side and the high-pressure side of the refrigeration installation, i.e. the high pressure is adjusted to a value of almost low pressure, which is equivalent to a pressure ratio of slightly more than 1. The reason for this is that the cooling effect regulated by the ambient-heat exchanger (condenser or gas cooler of the refrigerant circuit of the refrigeration system) is predominant, so that intensive cooling of the refrigerant is achieved and finally the condensing pressure level is set low.

The problem is solved in DE 102004046459B 3 by an air conditioning system for a vehicle in that a control element is actuated as a function of the ambient air temperature, with which a predetermined pressure ratio can be set or maintained between a high pressure and a low pressure in a refrigerant circuit of the air conditioning system. A bypass valve arranged in the bypass line is provided as a control element, so that the refrigerant flows either through the heat exchanger or through the bypass line while bypassing the heat exchanger. Such a bypass valve can also be designed with a plurality of intermediate positions, whereby a division of the refrigerant into a partial flow through the heat exchanger and a partial flow through the bypass line can be achieved. Alternatively, instead of a bypass valve as the regulating element, a pressure increasing means, which is designed, for example, as an expansion mechanism, can also be used between the heat exchanger and the refrigerant compressor of the refrigerant circuit, with which a sufficiently large pressure ratio can be regulated between a high pressure and a low pressure of the refrigerant circuit. Such a control element is activated when the ambient temperature falls below a predetermined temperature limit.

The main purpose of the refrigeration plant operation is to achieve and maintain a dehumidification mode for the cabin air in the case of low environmental loads, in order to specifically avoid emergency situations with a tendency for glass fogging.

Disclosure of Invention

The object of the present invention is therefore to provide an improved method for operating a refrigeration system of a vehicle, which refrigeration system comprises a heat exchanger as a refrigerant condenser or gas cooler for the operation of the refrigeration system, with which heat exchanger or gas cooler, in particular at low ambient temperatures, an increased high pressure level is generated in the refrigerant circuit of the refrigeration system with the start of the operation of the refrigeration system, and thus a stable operation of the refrigeration system, in particular for tempering an inlet air flow to be fed into the vehicle interior of the vehicle, is ensured. Furthermore, it is an object of the invention to provide a refrigeration plant for carrying out the method.

The object set forth at the outset is achieved by a method having the features of claim 1 or having the features of claim 2.

In order to operate a refrigeration system of a vehicle, comprising a refrigerant circuit with a heat exchanger, wherein the heat exchanger is flowed through by means of a controllable ambient air flow and can be operated as a refrigerant condenser or as a gas cooler for the operation of the refrigeration system, according to the invention according to the first proposed solution,

-controlling the amount of air of the ambient air flow flowing through the heat exchanger by means of a device in dependence on a temperature limit value of the ambient temperature of the vehicle in order to adjust a preset pressure ratio between a high pressure and a low pressure of the refrigerant circuit,

increasing the amount of air flowing through the heat exchanger by means of the device above a temperature limit, and

-reducing the amount of air flowing through the heat exchanger by means of the device in the case of an ambient temperature corresponding at most to a temperature limit.

In this method according to the invention, a drop in the high pressure in the refrigerant circuit, which is associated with a high condensation or cooling power at the heat exchanger, is avoided thereby, or conversely a rise in the high pressure is achieved thereby, i.e. the air quantity of the ambient air stream cooling the heat exchanger is reduced by means of the device. Accordingly, instead of the air flowing through the entire heat exchanger, accordingly, in the first refrigeration system operating mode only a partial surface of the heat exchanger is exposed or contacted by the ambient air flow. The control of the air quantity of the ambient air flow flowing through the heat exchanger is effected in dependence on the ambient temperature, i.e. a temperature limit which can be set, for example, to 6 ℃ for a reduced air quantity and 8 ℃ for an increased air quantity, since in this temperature range usually only a small amount of power is used and therefore only a small amount of heat is conducted away at the heat exchanger.

A second solution proposed according to the invention is characterized in that,

-controlling, by means of a device, the amount of air of the ambient air flow flowing through the heat exchanger as a function of a pressure difference limit of the pressure difference between the high pressure and the low pressure of the refrigerant circuit, wherein,

-increasing the amount of air flowing through the heat exchanger by means of said device in case the pressure difference is higher than the pressure difference value, and

-reducing the amount of air flowing through the heat exchanger by means of said device in the case of a pressure difference lower than or equal to a pressure difference limit between the high pressure and the low pressure of the refrigerant circuit.

In order to form a pressure difference between high and low pressures of the refrigerant cycle, a value of a high pressure value detected by a pressure (temperature) sensor is considered and a difference from a low pressure value is determined. If, in the case of chemical refrigerants, for example, a high pressure of more than 1bar above the low pressure occurs, the air quantity flowing through the heat exchanger is increased, otherwise, below this value a reduction of the air quantity is achieved. In the case of R744 as the refrigerant, the limit value of the differential pressure value may be defined as 5bar, for example.

The method according to the first and second solution according to the invention is preferably used for tempering an inlet air stream to be fed into a vehicle interior of a vehicle, i.e. for cooling and/or dehumidifying such an inlet air stream.

It is particularly advantageous if, in the method according to the invention, the device is designed as a controllable air supply device according to a development.

For this purpose, according to a further development, an air supply device is provided with a plurality of pivotable flaps which can be pivoted individually, jointly or in groups between an open position and a closed position. Such an air inlet device can be designed in the manner of a louver. The dampers can be pivoted in a motorized manner jointly between an open position and a closed position and can be shifted or adjusted by means of a control unit as a function of parameters, for example the static pressure level or the difference between low pressure and high pressure. The damper or vane is swung into an open position or a closed position depending on the ambient temperature or depending on the pressure difference value between the high pressure and the low pressure of the refrigerant cycle, thereby increasing or decreasing the air amount.

The dampers can also be grouped into at least two groups, whereby the dampers are adjusted in groups jointly in a motorized manner and in a manner controlled by the control unit, respectively. The partial air flow of the ambient air flow generated by the respective group can thus be controlled in terms of its air quantity by the control unit.

The dampers of such air input devices can also be individually adjusted in a motorized manner and in accordance with the control unit. This has the advantage that an approximately stepless control of the quantity of inlet air at the heat exchanger is achieved and the high pressure value can thus be influenced, similar to a fine control.

In order to be able to use the entire cooling surface of the heat exchanger, the cooling air flow from the ambient air flow is adjusted by means of the device to have a cross section comparable to the maximum cooling surface of the heat exchanger.

A further advantageous embodiment of the invention provides that the system is designed with at least two partial systems, wherein the partial systems correspond to mutually non-intersecting cooling surfaces of the heat exchanger in such a way that a partial cooling air flow generated by the partial systems from the ambient air flow acts on the cooling surfaces of the heat exchanger corresponding to the partial cooling air flow. The partial devices are each actuated independently of one another by means of a control unit, so that the partial cooling air flows are each generated by the partial devices from the ambient air flow and the air quantities thereof are controlled.

The second object is achieved by a refrigeration appliance having the features of claim 7.

According to the invention, such a refrigeration facility for a vehicle comprising a refrigerant circulation circuit with a heat exchanger is characterized in that,

the heat exchanger can be operated as a refrigerant condenser or as a gas cooler for the operation of a refrigeration system for carrying out the method according to the invention,

the heat exchanger can be flowed through by a controllable ambient air flow,

-means for distributing the heat exchanger with a quantity of air influencing the flow through the heat exchanger in order to generate a controlled ambient air flow, and

the refrigerant circuit has, in addition to the heat exchanger, a refrigerant compressor and an evaporator with a distributed expansion valve.

According to a further development, the device is designed as a controllable air inlet, wherein the air inlet has a plurality of pivotable flaps which can be pivoted individually, jointly or in groups between an open or closed position and an intermediate position.

Preferably, the device is designed for conditioning a cooling air flow from an ambient air flow having a cross section comparable to the maximum cooling surface of the heat exchanger. And thus can flow to the entire cooling surface of the heat exchanger.

Finally, according to a last preferred embodiment of the invention, the device is designed with at least two sub-devices such that the sub-devices correspond to mutually non-intersecting cooling surfaces of the heat exchanger and the ambient air flow generated by the sub-devices loads the cooling surfaces of the heat exchanger corresponding to the cooling air flow. The advantage of such a device is that the individual flow paths (Fluten) of the heat exchanger are completely separated from the air flow as required, in particular in a condenser or gas cooler comprising flow paths that are selectively loaded with refrigerant. Another criterion is the air loading of the heat exchanger connected upstream and/or downstream of the heat exchanger functioning as a condenser or gas cooler. In this way, the heat exchanger is not completely isolated from the air flow, but instead is partially flowed through by a partial air flow in order to achieve the required cooling power in this way.

Drawings

Further advantages, features and details of the invention emerge from the following description of a preferred embodiment and from the drawings. Shown here are:

FIG. 1 shows a circuit diagram of an embodiment of a refrigeration plant according to the invention with a heat exchanger and a device for generating a cooling air flow through the heat exchanger, and

fig. 2 shows a detailed view of a heat exchanger including an alternative embodiment of an apparatus for generating a cooling air flow through the heat exchanger.

List of reference numerals:

1 refrigerant circulation circuit

2 Heat exchanger

3 refrigerant compressor

4 evaporator

4.0 expansion mechanism

5 refrigerant collector

6 internal heat exchanger

7 device

7.0 air input device

7.01 air supply device 7.1 pivotable flap

7.1 sub-devices of device 7

7.10 air input device

7.11 swingable flap of air supply 7.10

7.2 sub-devices of device 7

7.20 air input device

7.21 swingable flap of air supply 7.20

8 control unit

10 refrigeration installation

Cooling surface of A1 Heat exchanger 1

Cooling surface of A2 Heat exchanger 1

L ambient air flow

L1 Cooling air flow

L11 partial Cooling air flow

L12 partial Cooling air flow

Flow direction of the refrigerant circulation circuit 1

Detailed Description

To illustrate the method according to the invention, the method used for this purpose is first described in advance and is shown in FIG. 1

A refrigeration appliance 10 for a vehicle is shown.

The refrigeration system 10 shown in fig. 1 comprises a refrigerant circuit 1 with carbon dioxide (R744) as refrigerant or with another suitable refrigerant. The refrigerant circuit 1 is operated in a refrigeration system operation (referred to below as AC operation), wherein the refrigerant circuit 1 can be supplemented with components known to the person skilled in the art for a heat pump operation for tempering an inlet air flow to be fed into a vehicle interior of a vehicle.

The refrigerant circuit 1 according to fig. 1 has a heat exchanger 2 which operates as a gas cooler or condenser for AC operation.

Furthermore, the refrigerant circuit 1 according to fig. 1 comprises, in addition to the heat exchanger 2, a refrigerant compressor 3, an evaporator 4 (to which an associated expansion device 4.0 is connected upstream), a refrigerant receiver 5 and an internal heat exchanger 6. The refrigerant of the refrigerant circuit 1 flows through these components in the flow direction S in a known manner.

In AC operation of the refrigerant circuit 1, the refrigerant compressed by means of the refrigerant compressor 3 flows in the flow direction S into the heat exchanger 2, in which it is cooled and condensed according to the air mass of the ambient air flow L1, and the heat of condensation is dissipated to the vehicle environment.

After the refrigerant leaves the heat exchanger 2, it is reduced in pressure in the evaporator 4 by means of the expansion means 4.0 through the high-pressure section of the interior heat exchanger 6 in order to absorb heat from the incoming air stream of the passenger cabin. Subsequently, the refrigerant is led back to the refrigerant compressor 3 through the refrigerant collector 5 and the low pressure section of the internal heat exchanger 6.

The sensors (pressure, temperature, pressure and temperature) required for proper system operation are omitted, since these sensors are known to the person skilled in the art.

The heat exchanger 2 is assigned a device 7 designed as an air inlet 7.0, by means of which the ambient air stream L is converted into a cooling air stream L1 and the heat exchanger 2 is acted upon by this cooling air stream in order to achieve cooling of the refrigerant in the same region.

This air inlet 7.0 is designed as a closable cooling air shutter with pivotable flaps 7.01 (also referred to as vanes) which can be pivoted jointly between an open position, in which all cooling surfaces of the heat exchanger 2 are exposed to all ambient air flow L as cooling air flow L1, and a closed position, in which the flaps 7.01 are closed so that the cooling surfaces of the heat exchanger 2 are not exposed to cooling air. Furthermore, intermediate positions can be realized in which the air quantity of the inlet air stream L1 guided through the damper 7.01 is reduced overall compared to the air quantity of the entire ambient air stream L.

The cross section of the cooling air flow L1 generated by the air inlet device 7.0 in the vehicle height direction (z-direction) corresponds at most to the cooling surface of the heat exchanger 2 which is likewise effective in all directions in the vehicle height direction.

The required surface area of the air inlet device can be varied, up to a value corresponding to the total effective cooling surface of the heat exchanger 2, on the basis of different designs of the cooling air duct and also on the basis of different possibilities of positioning of the air inlet device 7 in the x direction. The heat exchanger 2 as part of the overall cooler package (which may have other components, such as a high temperature cooler and/or a low temperature cooler) may itself also be oriented in a different inclined position.

The control of the damper 7.01 of the air supply 7.0 takes place by means of the control unit 8 as a function of parameters, for example the pressure conditions, i.e. the pressure difference in the refrigerant circuit 1. The static pressure level of the refrigerant circuit 1 has been adjusted to the target low pressure level of the plant operation, so that no stable continuous operation is set, that is to say the refrigerant compressor 3 cannot ensure a continuously stable pressure difference between the low pressure side and the high pressure side due to the high pressure drop in the low ambient temperature system, and the high pressure here approaches strongly the low pressure. This means that the resulting high pressure level is so low that no significant pressure ratio can be generated between the low pressure side and the high pressure side of the refrigeration system 10, i.e. the high pressure is set to almost the low pressure value, which is substantially equivalent to a pressure ratio which is slightly greater than 1. The reason for this is that the cooling effect produced by the heat exchanger 2 is predominant, so that intensive cooling of the refrigerant is achieved, ultimately resulting in a low condensation pressure level.

In AC operation, the damper 7.01 is controlled in a predefined pivot position, which corresponds to the open position or the closed position or an intermediate position between the open position and the closed position, as a function of, for example, the detected ambient temperature or a specific pressure difference.

For AC operation, the damper 7.01 is pivoted from the current position by means of the control unit 8 depending on the ambient temperature of the vehicle as a function of the ambient temperature of the vehicle. The ambient temperature is detected by means of a suitable temperature sensor and is supplied to the control unit 8 for evaluation, wherein for this purpose a temperature limit value is stored in the control unit 8.

If an ambient temperature greater than the temperature limit value is detected, the control unit 8 controls the air inlet 7.0 in such a way that the flap 7.01 is pivoted in the direction of its open position, whereby the air quantity of the cooling air flow L1 is increased by a predetermined amount. The greatest heat exchange is thus achieved by means of the cooling air flow with the greatest air quantity which is fed to the heat exchanger 2.

Conversely, if the ambient temperature reaches or falls below the temperature limit, the control unit 8 controls the air inlet 7.0 in such a way that the damper 7.01 is pivoted in the direction of its closed position, so that the air quantity of the cooling air flow L1 is reduced by a predetermined quantity.

A smaller air quantity is thus provided for the heat exchange of the heat exchanger 2 with the ambient air of the vehicle, as a result of which the condensation power when the heat exchanger 2 is operated as a refrigerant condenser or the cooling power when the heat exchanger 2 is operated as a gas cooler is also reduced relative to the entire ambient air flow L flowing through the heat exchanger 2. This enables the high pressure of the refrigerant circuit to be increased at low ambient temperatures when the refrigeration system 10 is started up, in order to achieve a sufficient pressure ratio between the low-pressure side and the high-pressure side of the refrigerant circuit 1, in order to ensure stable continuous operation, or in order to generate a sufficient high pressure during the operation of the refrigeration system, in order to ensure stable continuous operation.

The temperature limit may be set to, for example, 6 ℃ for decreasing the air quantity of the cooling air flow L1 and 8 ℃ for increasing the air quantity of the cooling air flow L1, since in this range it can already be assumed that: only a small amount of power is converted on the system side, i.e. via the refrigerant circuit 1, and therefore only a small amount of heat is dissipated at the heat exchanger 2.

Alternatively or additionally to the temperature limit, a pressure difference limit may be saved in the controller 8. For this purpose, the high pressure value detected by the pressure (temperature) sensor is taken into account. If, in the case of a chemical refrigerant, the high pressure is, for example, more than 1bar higher than the low pressure, the air quantity of the cooling air stream L1 flowing through the heat exchanger 2 is increased, otherwise below this value a reduction of the air quantity of the cooling air stream L1 flowing through the heat exchanger 2 is achieved. In the case of R744 refrigerant, a value of, for example, 5bar can be specified as a limit value for the pressure difference between the high pressure and the low pressure of the refrigerant circuit 1.

If a pressure difference greater than the pressure difference threshold value is detected, the control unit 8 controls the air inlet 7.0 in such a way that the flap 7.01 is pivoted in the direction of its open position, whereby the air quantity of the cooling air flow L1 is increased by a predetermined amount. The greatest heat exchange is thus achieved by means of the cooling air flow with the greatest air quantity which is fed to the heat exchanger 2.

Conversely, if the pressure difference reaches the pressure difference limit or the pressure difference drops below this pressure difference value, the control unit 8 controls the air inlet 7.0 in such a way that the flap 7.01 is pivoted in the direction of its closed position, so that the air quantity of the cooling air flow L1 is reduced by a predetermined quantity.

A smaller air quantity is thus provided for the heat exchange of the heat exchanger 2 with the ambient air of the vehicle, whereby the condensation power is also reduced in the operation of the heat exchanger 2 as a refrigerant condenser or the cooling power is reduced in the operation of the heat exchanger 2 as a gas cooler, compared to the flow through with the entire ambient air flow L. The high pressure of the refrigerant circuit is thereby increased at low ambient temperatures at the beginning of the operation of the refrigeration system 10 in order to achieve a sufficient pressure ratio between the low-pressure side and the high-pressure side of the refrigerant circuit 1 in order to ensure stable continuous operation, or in order to generate a sufficient high pressure during the operation of the refrigeration system in order to ensure stable continuous operation.

As opposed to a common control damper 7.01, it is alternatively also possible for the individual dampers 7.01 to be actuated individually by the control unit 8. It is thereby possible to completely separate the individual flow paths to the heat exchanger 2 from the air flow as required, in particular in a heat exchanger 2 functioning as a condenser or gas cooler comprising flow paths (Fluten) which are selectively supplied with refrigerant. Another criterion is the air load of the heat exchanger connected upstream and/or downstream of the heat exchanger 2 functioning as a condenser or gas cooler. In this way, the heat exchanger is not completely isolated from the air flow, but instead is partially flowed through by a partial air flow in order to achieve the required cooling power in this way.

The air supply 7.0 can also be designed in such a way that the dampers 7.01 are grouped together and each group of such dampers 7.01 is controlled jointly by the control unit 8 and thus oscillates independently of the other damper groups. Each set of such dampers produces a partial air flow of the ambient air flow, the air volume of these partial air flows being produced independently of the air volume of the other partial air flow.

An equivalent embodiment of the device 7 designed as an air inlet 7.0 is that it is divided into at least two partial devices 7.1 and 7.2, which are shown schematically in fig. 2. Each such sub-device 7.1 and 7.2 is designed as an air inlet 7.10 and 7.20 with a damper 7.11 and 7.21. The ambient air flow L flowing onto such a device 7 is divided by the two sub-devices 7.1 and 7.2 into two partial cooling air flows L11 and L12, which in turn load the two mutually non-intersecting cooling surfaces a1 and a2 of the heat exchanger 2.

In such an air inlet device 7, which is divided into two sub-devices 7.1 and 7.2, a heat exchanger 2 can be used, which is designed with a dual flow path comprising a first flow path 2.1 and a second flow path 2.2. The first flow path 2.1 is arranged below the second flow path 2.2 in the vehicle height direction (z-direction) and thus corresponds to the cooling surface a1, while the second flow path 2.2 corresponds to the cooling surface a 2.

The throughflow of the double flow path of the heat exchanger 2 is effected if the ambient temperature of the vehicle is greater than the temperature limit or the pressure difference between the high pressure and the low pressure of the refrigerant circuit 1 is greater than a pressure difference threshold. In this case, the control unit 8 operates the two air inlet devices 7.10 and 7.20 simultaneously in the following manner: the dampers 7.11 and 7.21 of the air inlet device are pivoted by a preset amount in the direction from a preset position towards their open position, whereby the air quantity of each of the two partial cooling air streams L11 and L12 is increased.

The throughflow of the single flow path of the first flow path 2.1 of the heat exchanger 2 is achieved if the ambient temperature of the vehicle is equal to or less than the temperature limit or the pressure difference between the high pressure and the low pressure of the refrigerant circuit 1 is equal to or less than the pressure difference threshold. In such a partially heat exchanger 2 loaded with refrigerant, the lower air inlet 7.20, i.e. the damper 7.21 of the lower air inlet, is closed, or the control unit 8 regulates the air quantity of the partial cooling air flow generated by the air inlet 7.20 to a predetermined value in the direction of the closed position of the air inlet. In this case, the partial cooling air stream L11 of the upper air inlet 7.10 flows onto the cooling surface a1 of the second flow path 2.2 of the heat exchanger 2 through which no refrigerant flows. If the heat exchanger 2 is arranged in a cooler group with at least one cooler, for example a water cooling circuit, for cooling the combustion engine, the cooler can be loaded with a partial cooling air stream L11, or the air quantity of the partial cooling air stream can be controlled.

For aerodynamic reasons, however, it is reasonable to displace the device 7 in the direction as close as possible to the vehicle cooling air inlet, that is to say into the region of the vehicle housing of the vehicle, which however results in the entire cooler package being influenced in the same way by the reduced total air flow L1 as the damper 7.01 is moved, and not only by the individual partial regions of the cooler package, as is achieved according to the embodiment of fig. 2.

The method for conditioning an inlet air flow into a vehicle interior, in particular for cooling and/or drying the inlet air flow, which is carried out with such a refrigeration system according to fig. 1 and 2, ensures stable refrigeration system operation at ambient temperatures around freezing or slightly above freezing.