KR20190133595A - Refrigerant circuit with an expansion-compression device and method for operating the refrigerant circuit - Google Patents

Abstract

The present invention relates to a refrigerant circuit (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i) for an air conditioning system of a vehicle. The refrigerant circuit (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i) comprises: one or more compressors (2), a first heat exchanger (3) operable as a condenser/gas cooler of refrigerant; an expansion-compression device (4) having an expansion component (4a) and a compression component (4b); a second heat exchanger (5) operable as an evaporator of the refrigerant; and a first flow path (6) and second flow path (7). The first flow path and the second flow path are formed to extend from a branch point (8) to an inlet (9) so that the refrigerants can be supplied in parallel. The inlet (9) is arranged between the compressor (2) and the first heat exchanger (3). The expansion component (4a), the second heat exchanger (5) and the compressor (2) are formed in the flow direction of the refrigerant in the first flow path (6). The compression component (4b) is formed in the second flow path (7). The present invention also relates to a method for operating the refrigerant circuits (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i) for an air conditioning system of a vehicle.

Description

REFRIGERANT CIRCUIT WITH AN EXPANSION-COMPRESSION DEVICE AND METHOD FOR OPERATING THE REFRIGERANT CIRCUIT}

The present invention provides an air conditioner of an automobile comprising one or more compressors, a first heat exchanger operable as a condenser / gas cooler of refrigerant, an expansion-compression device having an expansion component and a compression component, and a second heat exchanger operable as an evaporator of refrigerant. A refrigerant circuit for a system.

The invention also relates to a method for operating the refrigerant circuit.

In particular, the discovery of ozone destruction of the stratosphere by chlorine-containing refrigerants and the discussion of alternative refrigerants resulting from the prohibition of such refrigerants have presented various solutions with the use of natural refrigerants. However, the thermodynamic properties of energy, safety-related or environmentally friendly refrigerants such as carbon dioxide, ammonia, water and air limit the widespread use of refrigerants. Starting from the natural refrigerants mentioned, carbon dioxide is considered to be a technically safe and thermodynamically working material with some properties suitable for use in refrigerant circuits in compression coolers.

Work processes that use carbon dioxide as a refrigerant are thermodynamically, e.g., in supercritical heat release, in particular in comparison to the isothermal, isothermal change of subcritical heat release in traditional steam cooling processes using R134a or R290 as refrigerant. It is distinguished from the process using other refrigerants of the isostatic and non-isothermal state changes of the refrigerant. The terms supercritical and subcritical heat dissipation here refer to limitations as characteristic states of the refrigerant. Supercritical heat release is also referred to as the process as a transcritical process.

In thermodynamic processes involving subcritical heat release, including compression of the refrigerant, supercritical heat release, isenthalpic expansion, and evaporation of the refrigerant, the expansion of the refrigerant, in particular in the two-phase region, results in high thermodynamic losses. In particular, it is characteristic in applications with the outlet temperature of the refrigerant of the high pressure heat exchanger in the range of 20 ° C to 45 ° C. In order to achieve efficiencies comparable to traditional subcritical steam cooling processes using other refrigerants, the refrigerants must be expanded operably in transcritical critical operating processes.

US 3 934 424 A describes an expansion-compression device for the vapor cooling process of a refrigerant. The apparatus includes a rotor having radial passages that expand the refrigerant and drive the rotor using the kinetic energy of the expanded refrigerant. The rotor is connected to the drive of the compressor to compress the refrigerant. As a result, the refrigerant is operably expanded by the expansion-compression device before evaporation, in which case the energy obtained during expansion is used for the compression of the refrigerant, thereby increasing the operating efficiency of the refrigerant circuit.

The expansion component of the expansion-compression device is arranged between the outlet of the high pressure heat exchanger and the inlet leading into the heat exchanger operating as an evaporator. Kinetic energy is recovered when the refrigerant is expanded from the high pressure level to the low pressure level in the expansion component, and this kinetic energy is transferred from the low pressure level at the outlet of the evaporator in the compression component connected with the expansion component via the drive shaft to the inlet of the main compressor. It is precompressed to compress the refrigerant to a relatively higher intermediate pressure level at. In addition to the relatively large specific evaporation capacity and the relatively low specific compression capacity, the high pressure level and the suction density at the inlet leading into the main compressor connected thereto also lead to higher operating efficiency of the steam cooling process.

Refrigerant circuits known in the art are provided with active actuating elements for controlling the expansion-compression device, which makes them particularly effective in air conditioning systems of automobiles with many different load points in very unstable operation due to various driving situations. impossible to use.

In addition, the expansion component of the device and the compression component of the device for precompression are respectively arranged in the main mass flow of the refrigerant so that the state of the refrigerant at the inlet of the main compressor is directly affected by the expansion compression device. Thus, for example, the higher running speed of the motor vehicle, the high pressure level of the refrigerant circuit and thus the energy recovery of the expansion-compression device is low. As a result, less energy can be recovered with the expansion component of the device, which results in lower pressure levels and densities at the outlet of the compression component of the device. However, in order to maintain a constant cooling capacity in the evaporator by providing a constant mass flow of refrigerant in the overall system, it must be operated at high speed, especially when using a main compressor which is electrically driven with a constant stroke volume. The change in speed of the compressor can be detected by the noise in the vehicle.

It is an object of the present invention to provide a refrigerant circuit having an expansion-compression device, in particular for an air conditioning system of a motor vehicle having an electric, internal combustion engine or electric and internal combustion engine coupled drive. The refrigerant circuit must be capable of operating at maximum heat capacity or cooling capacity and at maximum efficiency, in which case the kinetic energy must be recovered when the refrigerant is expanded from the high pressure level to the low pressure level or the suction pressure level, and this kinetic energy is in particular a compressor. It must be available as part of the dose. In addition, the expansion-compression device must be suitable for use in an air conditioning system of a vehicle having many different load points in operation that is very unstable due to various driving situations. At the same time, for example, a constant mass flow of refrigerant can be provided throughout the entire system to maintain a constant cooling capacity of the evaporator without the need to constantly adjust the speed of the compressor to minimize noise emissions and increase the comfort of the cabin. It should be possible.

It is also an object of the present invention to provide a method of operating a refrigerant circuit with an expansion-compression device, in particular a refrigerant circuit for an air conditioning system of a motor vehicle.

The problem is solved by an object or a method having the features of the independent claims. Improvements are given in the dependent claims.

This problem is solved by a refrigerant circuit for an air conditioning system of an automobile. The refrigerant circuit has one or more compressors, a first heat exchanger operable as a condenser / gas cooler of refrigerant, an expansion-compression device having an expansion component and a compression component, and a second heat exchanger operable as an evaporator of refrigerant. The air conditioning system is particularly suitable for automobiles comprising internal combustion engine drives, electric drives, also referred to as electric vehicles, and hybrid drives in which the electric and internal combustion engines are combined.

If the liquefaction of the coolant takes place in subcritical operation of the coolant circuit, such as when using coolant R134a or under certain ambient conditions using carbon dioxide, the heat exchanger is referred to as a condenser. Part of the heat transfer is at a constant temperature. In case of over-critical operation or over-critical heat is released in the heat exchanger, the temperature of the refrigerant is constantly reduced. In this case the heat exchanger is also referred to as a gas cooler. Operation above the threshold may occur, for example, in certain ambient conditions or modes of operation of the refrigerant circuit using carbon dioxide as the refrigerant.

According to the idea of the present invention, the refrigerant circuit includes a first flow path and a second flow path, wherein the first flow path and the second flow path are each capable of simultaneously supplying refrigerant in such a manner as to extend from the branch point to the inlet. It is formed. In this case the inlets of the flow paths are arranged between the compressor and the first heat exchanger. In addition, an expansion component of an expansion-compression device, a second heat exchanger, and a compressor are formed in a flow direction of the refrigerant in the first flow path, and a compression component of the expansion-compression device is formed in the second flow path. Formed.

The first flow path is preferably fed with a main mass flow of refrigerant, while a bypass mass flow flows through the second flow path.

The expansion component and the compression component of the expansion-compression device are mechanically connected to each other such that the kinetic energy converted from the expansion of the refrigerant by the expansion component is transferred directly to the compression component for compressing the refrigerant.

The expansion component and the compression component of the expansion-compression device are preferably fixed on the shaft of the cavity.

According to a first alternative embodiment of the invention, the branching points of the first flow path and the second flow path are formed as separators or collectors. In addition, a device is arranged for expanding the refrigerant between the first heat exchanger and the branching point such that the refrigerant at the branching point has a lower pressure level than at the outlet of the first heat exchanger.

The device for expanding the refrigerant is preferably formed as an expansion member, in particular as an expansion valve or as a valve with an expansion function, in particular as a three-way valve.

According to a second alternative embodiment of the invention, the branch point is formed as a T-shaped member such that the pressure level of the coolant at the outlet of the first heat exchanger corresponds to the pressure level of the coolant after the branch point perfusion, so that It is arranged at the outlet. In this case, the T-shaped member at the branch point flows through with little loss through the refrigerant.

According to an improvement of the present invention, a refrigerant circuit having an internal heat exchanger is formed, and the internal heat exchanger is arranged to thermally connect the first flow path and the second flow path to each other. The internal heat exchanger is considered a circuit heat exchanger, in which case the circuit heat exchanger is provided for heat transfer of the refrigerant guided through the first flow path and the refrigerant guided through the second flow path.

Particularly preferably, the internal heat exchanger is arranged in the first flow path between the branching points of the first and second flow paths and the expansion component of the expansion-compression device.

The internal heat exchanger is preferably arranged in the second flow path between the branch points of the first and second flow paths and the compression component of the expansion-compression device. In this case, an apparatus for expanding the refrigerant is arranged in front of the internal heat exchanger in the flow direction of the refrigerant. The device for expanding the refrigerant is preferably formed as an expansion member, in particular as an expansion valve.

According to a preferred embodiment of the present invention, a sensor for determining the state of the refrigerant is disposed at the outlet of the refrigerant of the second heat exchanger. Alternatively or additionally a sensor is arranged at the inlet leading to the compression component of the expansion-compression device to determine the state of the refrigerant. In this case the sensor is preferably formed as a connected pressure sensor / temperature sensor or as a pressure sensor or as a temperature sensor, respectively.

In an alternative first embodiment of the refrigerant circuit in which the branch point is formed as a separator or collector of the refrigerant, the apparatus for expanding the refrigerant is preferably a thermostatic expansion valve having a low pressure side first flow passage and a high pressure side second flow passage. Formed. In this case the first flow passage is arranged at the outlet of the second heat exchanger in the first flow passage, and the second flow passage is disposed between the first heat exchanger and the branching points of the first flow passage and the second flow passage. It is.

In a second alternative embodiment of the refrigerant circuit with an internal heat exchanger, the device for expanding the refrigerant is preferably formed as a thermostatic dosing valve having a low pressure side first flow passage and a high pressure side second flow passage. In this case, the first flow passage is disposed at the outlet of the second heat exchanger in the first flow passage, and the second flow passage is a branching point of the first flow passage and the second flow passage within the second flow passage. It is arranged between the internal heat exchangers.

According to an improvement of the present invention, the thermostatic expansion valve or the thermostatic dosing valve is formed with a closing member that is movably supported, and the closing member is formed according to the state of the refrigerant in the first flow passage. And configured to continuously change the flow cross sectional area of the second flow passage between two end positions within the first flow passage. The refrigerant expands as it flows through the second flow passage.

The thermostatic expansion valve preferably increases the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the first flow passage is too low or the superheat degree is too high, and the pressure of the refrigerant in the first flow passage is increased. If this is too large or the degree of superheat is too small, it is configured and formed to reduce the flow cross sectional area of the second flow passage.

The thermostatic dosing valve preferably reduces the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the first flow passage is too low or the superheat degree is too high, and the pressure of the refrigerant in the first flow passage is reduced. If it is too large or the degree of superheat is too low, it is configured and formed to increase the flow cross sectional area of the second flow passage.

According to a further preferred embodiment of the invention, a refrigerant circuit having a third flow path is formed, which extends from the branch to the inlet. In this case the inlet is arranged between the expansion component of the expansion-compression device and the second heat exchanger in the first flow path.

According to a first alternative embodiment, the branch point of the third flow path is formed as a device for expanding the expansion member and the refrigerant, in particular as a three-way valve with one or more expansion functions. In this case the branching point of the third flow path formed as the three-way valve with expansion function and the expansion member is preferably arranged between the first heat exchanger and the branching point of the first flow path and the second flow path. The branching point of the third flow path alternatively formed as a three-way valve with one or more expansion functions, in particular in the second alternative embodiment of the refrigerant circuit with an internal heat exchanger, is preferably a branching point in the first flow path. And an internal heat exchanger.

According to a second alternative embodiment, an expansion member is provided in the third flow path instead of forming a branching point of the third flow path as the expansion member.

An expansion member, in particular an expansion valve, in particular an electronic expansion valve, is arranged next to the compression component of the expansion-compression device in the direction of flow of the refrigerant in the second flow path.

The refrigerant circuit can also be formed with at least one collector disposed after the first heat exchanger in the flow direction of the refrigerant.

The coolant circuit can likewise comprise at least one accumulator, which is arranged in front of the inlet of the compressor in the direction of flow of the coolant.

The problem of the invention is also solved by the method according to the invention for operating a refrigerant circuit for an air conditioning system of a motor vehicle. The method includes the following steps:

Dividing the total mass flow of refrigerant into a main mass flow passing through the first flow path and a bypass mass flow passing through the second flow path at branch points of the flow paths,

Expanding the refrigerant of the main mass flow guided through the first flow path to a low pressure level when flowing through the expansion component of the expansion-compression device,

Compressing the refrigerant of the bypass mass flow guided through the second flow path to a high pressure level when flowing through the compression component of the expansion-compression device, wherein the refrigerant expansion of the main mass flow when flowing through the expansion component Time converted kinetic energy is used to compress the refrigerant in the bypass mass flow as it flows through the compression component, and

At the inlet of the flow paths, a refrigerant of the main mass flow and a refrigerant of the bypass mass flow which are compressed to a high pressure level in a compressor.

The refrigerant of the bypass mass flow through the second flow path is preferably compressed from a medium pressure level to a high pressure level.

According to a first alternative embodiment of the invention, the refrigerant of the total mass flow expands from the high pressure level to the intermediate pressure level and at the branch point formed as a separator a bypass mass consisting of the main mass flow consisting of the liquid refrigerant and the refrigerant in the vapor state Divided into flows.

Preferably the refrigerant of the main mass flow guided through the first flow path expands from a medium pressure level to a low pressure level, and the refrigerant of the bypass mass flow guided through the second flow path is a high pressure at an intermediate pressure level. Compressed to level.

According to a second alternative embodiment of the invention, the total mass flow of the high pressure level refrigerant is divided into a main mass flow and a bypass mass flow. The refrigerant in the main mass flow then expands from the high pressure level to the low pressure level and the refrigerant in the bypass mass flow expands from the high pressure level to the intermediate pressure level.

A further advantage is that when flowing through an internal heat exchanger that thermally connects the first flow path and the second flow path, the refrigerant of the high pressure level of the main mass flow is cooled while releasing heat to the refrigerant of the bypass mass flow, while At medium pressure levels the refrigerant of the bypass mass flow evaporates while absorbing heat from the refrigerant of the bypass mass flow.

According to one refinement of the invention, the intermediate pressure level of the bypass mass flow of the refrigerant is adjusted so that the medium pressure level refrigerant is in the two phase region.

The intermediate pressure level of the refrigerant is preferably adjusted in particular in the first alternative embodiment of the invention so that the medium pressure level of the refrigerant is adjusted such that the refrigerant has a state in the two phase region when it enters the separator, in which case the By adjusting the intermediate pressure level, the ratio of the main mass flow and the bypass mass flow of the refrigerant is set.

According to a further preferred embodiment of the invention, the total mass flow or bypass mass flow of the refrigerant is compressed according to the pressure and / or temperature of the refrigerant at the outlet of the second heat exchanger acting as an evaporator or the compression of the expansion-compression device. It is regulated by the pressure and / or temperature of the refrigerant at the inlet leading into the component.

According to a first alternative embodiment of the invention, the total mass flow of the refrigerant is controlled by an expansion member formed before the branch point in the flow direction of the refrigerant. Low pressure or high superheat of the refrigerant in the main mass flow at the outlet of the heat exchanger operating as an evaporator increases the flow cross-sectional area of the expansion member, while high pressure of the refrigerant in the main mass flow at the outlet of the heat exchanger is high. Or low superheat, the flow cross-sectional area of the expansion member is reduced.

According to a second alternative embodiment of the invention, the bypass mass flow of the refrigerant is preferably controlled by an expansion member formed in front of the internal heat exchanger in the flow direction of the refrigerant. If the pressure of the refrigerant of the main mass flow at the outlet of the heat exchanger operating as an evaporator is low or the superheat is high, the flow cross-sectional area of the expansion member is reduced, and the pressure of the refrigerant of the main mass flow at the outlet of the heat exchanger is high or overheated. Lower degrees increase the flow cross section of the expansion member.

The refrigerant circuit according to the invention with an expansion-compression device and the method according to the invention for operating said refrigerant circuit in summary has various advantages as follows:

By the modular construction of the refrigerant circuit, the conventional refrigerant circuit can be extended to include additional components without having to change the main compressor, evaporator or condenser / gas cooler, in which case the optimization of the components is possible,

-Maximum heat capacity and cooling capacity of the refrigerant circuit,

-Maximum efficiency in the operation of the refrigerant circuit,

The rotational speed of the main compressor can be reduced to minimize noise and improve the acoustics of the refrigerant circuit,

-Refrigerants such as R744a and R1234yf that can operate in sub-threshold ranges, as well as refrigerants such as R744 that can operate in excess of critical ranges, and

-Minimal operating costs, manufacturing costs and maintenance costs.

Further details, features and advantages of embodiments of the present invention are described with reference to the associated drawings, wherein the first and second flow paths, the expansion-compression device, the compressor and the first and second heat exchangers respectively extend from the branch to the inlet. It appears from the following description of embodiments of refrigerant circuits with groups. In drawing:
1A shows a first refrigerant circuit having branch points formed as separators or collectors,
FIG. 1B shows a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit of FIG. 1A, and FIG.
FIG. 2A shows a second refrigerant circuit similar to the first refrigerant circuit of FIG. 1A with a third flow path as a bypass bypassing the circumference of the expansion-compression device,
FIG. 2B shows a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit of FIG. 2A, and FIG.
3 shows a third refrigerant circuit similar to the first refrigerant circuit of FIG. 1A with a thermostatic expansion valve,
4 shows a fourth refrigerant circuit similar to the third refrigerant circuit of FIG. 3 with a third flow path as a bypass bypassing the circumference of the expansion-compression device,
5a shows a fifth refrigerant circuit with an internal heat exchanger,
FIG. 5B shows a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit of FIG. 5A, and FIG.
6A shows a sixth refrigerant circuit similar to the fifth refrigerant circuit of FIG. 5A with a third flow path as a bypass bypassing the circumference of the expansion-compression device,
FIG. 6B shows a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit of FIG. 6A, and FIG.
FIG. 7 shows a seventh refrigerant circuit similar to the fifth refrigerant circuit of FIG. 5A with a thermostatic dosing valve,
8 shows an eighth refrigerant circuit similar to the seventh refrigerant circuit of FIG. 7 with a third flow path as a bypass bypassing the circumference of the expansion-compression device, and
9 shows a ninth refrigerant circuit similar to the eighth refrigerant circuit of FIG. 8 having a thermostatic expansion valve with a switch-off function and a control valve without expansion function.

1a shows a first refrigerant circuit 1a having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The refrigerant circuit 1a is formed with a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path are each at the inlet 9 at the branch point 8. ) And run parallel to each other. The branch point 8 is formed as a separator 8a or a collector.

Inside the first flow path 6 is an expansion component 4a of the expansion-compression device 4 in the flow direction of the refrigerant, a second heat exchanger 5 acting as an evaporator and a main compressor of the refrigerant circuit 1a. A working compressor 2 is formed. The first flow path 6 is supplied with liquid refrigerant from the separator 8a or the collector. When the liquid refrigerant flows through the expansion component 4a of the expansion-compression device 4, it is operably expanded to the two-phase region from the intermediate pressure level to the low pressure level and is supplied to the evaporator 5. When flowing through the evaporator 5, the liquid portion of the refrigerant evaporates while absorbing heat. The refrigerant is then sucked by the compressor 2 and compressed to a high pressure level.

Inside the second flow path 7 formed as a bypass of the first flow path 6, a compression component 4b of the expansion-compression device 4 is arranged. The second flow path 7 is supplied with gaseous refrigerant from the separator 8a or collector. The refrigerant is compressed from an intermediate pressure level to a high pressure level when flowing through the compression component 4b of the expansion-compression device 4.

On the inlet 9, the main mass flow guided through the first flow path 6 and the bypass flow guided through the second flow path 7 are mixed and guided to the first heat exchanger 3. When flowing through the first heat exchanger 3, which acts as a condenser / gas cooler, the refrigerant is liquefied under heat dissipation, and then expands from a high pressure level to a medium pressure level when flowing through the expansion member 10 to the separator 8a. Is supplied. The refrigerant circuit 1a is closed. The expansion member 10 can preferably be formed as an expansion valve.

The state and change of state of the refrigerant inside the refrigerant circuit 1a are shown in FIG. 1B in a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit 1a. The reference numerals respectively show the state change when flowing through the components of the refrigerant circuit 1a or the state at a specific point of the refrigerant circuit 1a.

The evaporator 5 and the expansion component 4a of the expansion-compression device 4, the compressor 2 and the chiller or accumulator, for example not shown in the figures, disposed on the suction side in the first flow path 6. The second flow path 7 formed as a bypass bypassing the perimeter of the total mass flow can be divided into a main mass flow and a bypass mass flow of the refrigerant. The total mass flow is the sum of the main mass flow and the bypass mass flow of the refrigerant and flows into the separator 8a through the condenser / gas cooler 3 and the expansion member 10 arranged on the high pressure side. The total mass flow of the refrigerant is divided into a main mass flow and a bypass mass flow at the first heat exchanger 3 disposed on the high pressure side and the branch point 8 disposed downstream of the expansion member 10. The refrigerant is then supplied in the separator 8a at an intermediate pressure level with the proportion of liquid supplied as the main mass flow into the first flow path 6 and the proportion of gas phase supplied into the second flow path 7 as a bypass mass flow. Divided into divided into.

In this case, the intermediate pressure level of the coolant is adjusted in such a way that the coolant has one state inside the two-phase region as it flows into the separator 8a. The change in the intermediate pressure level alters the ratios, in particular the liquid and gaseous mass ratios, and thus also the ratio of the main mass flow to the bypass mass flow of the refrigerant, in particular in this case the bypass mass. The flow is regulated as a result of the steam mass fraction at the inlet leading into the separator 8a.

The total mass flow of refrigerant determined by the rotational speed of the compressor 2 and the bypass mass flow is determined at the outlet of the evaporator 5 or at the branching points 8, 8a, in particular the compression component of the expansion-compression device 4 ( The expansion member 10 is adjusted to an intermediate pressure level in accordance with the pressure and / or temperature of the refrigerant at the inlet leading to 4b). The pressure and / or temperature of the main mass flow of refrigerant at the outlet of the evaporator 5 is determined by the sensor 11. According to an alternative embodiment, the pressure and / or temperature of the bypass mass flow of the refrigerant at the inlet leading into the compression component 4b of the expansion-compression device 4 is detected by the sensor 12. In this case the sensors 11, 12 are each formed as a connected pressure sensor / temperature sensor or as a pressure sensor or as a temperature sensor.

On the one hand, if the pressure of the main mass flow of the refrigerant at the outlet of the evaporator 5 is too low or the superheat of the refrigerant at the outlet of the evaporator 5 is too high, the flow cross-sectional area of the expansion member 10, i.e. the expansion The member 10 is further opened. On the other hand, if the pressure of the main mass flow of the refrigerant at the outlet of the evaporator 5 is too high or the superheat of the refrigerant at the outlet of the evaporator 5 is too low, the flow cross-sectional area of the expansion member 10, ie the The expansion member 10 is further closed.

The control strategy cited can be applied to control by the sensor 12, in which case the target value for pressure or temperature is at a high level. The pressure or temperature value detected by the sensor 12 is used to directly adjust the intermediate pressure level in accordance with predetermined target values, the target values being for example intermediate optimized for the operating point for adjustment. It is stored in the properties field of the pressure level.

The kinetic energy of the main mass flow of refrigerant, recovered when flowing through the expansion component 4a of the expansion-compression device 4, compresses the bypass flow through the compression component 4b of the expansion-compression device 4. Used to The expansion component 4a and the compression component 4b of the expansion-compression device 4 can then be arranged on a common mechanical shaft, so that the kinetic energy between the components is transferred directly.

The additional heat generated when compressing the bypass mass flow is transferred from the condenser / gas cooler 3 to the air mass flow to be supplied to the surroundings or to the cabin, depending on the operating mode of the refrigerant circuit or the air conditioning system of the vehicle. Thus, heat can be used to heat the air in the cabin when the air conditioning system is operating in heat pump mode or reheat mode.

2a shows a second refrigerant circuit 1b having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The second refrigerant circuit 1b likewise has a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path each have a branching point formed as a separator 8a ( Extends from 8) to the inlet (9). Therefore, the second refrigerant circuit 1b is formed similarly to the first refrigerant circuit 1a of FIG. 1A. The refrigerant circuits 1a and 1b are similar in function. In addition, the same components of the refrigerant circuits 1a and 1b have been provided with the same reference numerals.

The main difference between the first refrigerant circuit 1a of FIG. 1A and the second refrigerant circuit 1b of FIG. 2A is a bypass bypassing the expansion-compression device 4, which extends from the branch point 13 to the inlet 15. In the formation of the third flow path 14. In this case, the branch point 13 disposed between the first heat exchanger 3 and the separator 8a serves as a three-way valve having an expansion function and in particular the expansion member 10 of the first refrigerant circuit 1a. It is formed as a replaceable expansion member 13a. The three-way valve is in particular formed according to FIG. 2A as a 3 / 2-way valve or a 3 / 3-way valve. According to an alternative embodiment not shown in the figures, instead of the three-way valve, a separate controllable expansion member, in particular an expansion valve, is provided. The inlet 15 is arranged in the first flow path 6 between the expansion component 4a of the expansion-compression device 4 and the second heat exchanger 5, so that the expansion-compression device 4 ) Can be shut down if necessary.

The expansion-compression device 4 can thus be deactivated, in particular to avoid cycle operation in certain operating modes of the low load range. In this case, the total mass flow of the refrigerant is expanded from the high pressure level directly to the low pressure level and fed to the evaporator 5 when flowing through the branch point 13 formed as a three-way valve with an expansion function. A particular mode of operation is also shown in FIG. 2B where a pressure-enthalpy diagram for the sub-critical operation of the second refrigerant circuit 1b is shown, wherein the pressure-enthalpy diagram is shown in broken lines. The flow path to the separator 8a is closed. During operation of the refrigerant circuit 1b in which the third flow path 14 is closed, the refrigerant is at a high pressure level when flowing through the branching point 13 or the expansion member 13a formed as a three-way valve with the expansion function 13. At an intermediate pressure level at which is fed to the separator 8a.

With the formation of a branching point 13 in which the expansion member is integrated as a 3 / 3-way valve instead of a 3 / 2-way valve, the operation of the expansion-compression device 4 is turned on and off between the operating modes of the refrigerant circuit 1b. The conversion can be performed more easily. In order to avoid refrigerant / oil movement into the compression component 4b of the expansion-compression device 4 or unintentional reverse overflow of the refrigerant to a high pressure level, a check member 16 is provided in the second flow path 7. Is provided. In particular, a check member formed as a check valve is arranged between the compression component 4b and the inlet 9. Instead of the check member 16, an alternatively active shutoff valve may be provided.

3 shows a third refrigerant circuit 1c having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The third refrigerant circuit 1c likewise has a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path each have a branching point formed as a separator 8a ( Extends from 8) to the inlet (9). Therefore, the third refrigerant circuit 1c is formed similarly to the first refrigerant circuit 1a of FIG. 1A. The refrigerant circuits 1a, 1b and 1c have similar functions. In addition, the same components of the refrigerant circuits 1a, 1b, 1c are again provided with the same reference numerals.

The main difference between the first refrigerant circuit 1a of FIG. 1A and the third refrigerant circuit 1c of FIG. 3 lies in the formation of a thermostatic expansion member as the expansion member 17a, in which case the expansion member is an active expansion member ( 10) and the compression component 4b of the sensor 11 arranged at the outlet of the evaporator 5 in the first flow path 6 or alternatively the expansion-compression device 4 in the second flow path 7. To replace the sensor 12 of the first refrigerant circuit 1a, which is provided at an inlet leading into the hole.

The thermostatic expansion valve 17a disposed at the outlet of the evaporator 5 on the low pressure side with the first flow passage is in particular flowed by the gaseous refrigerant, and consequently the pressure or temperature of the refrigerant in the expansion member 17a. As a result, the closing member 18a formed as a tappet having a spherical head is moved. The thermostatic expansion valve 17a is disposed between the first heat exchanger 3 and the separator 8a on the high pressure side having the second flow passage.

The head of the closing member 18a forms a flow cross sectional area of the high pressure side flow passage of the expansion valve 17a and is arranged such that the high pressure side perfusion can be interrupted or continuously adjusted. The high pressure level of refrigerant is expanded when flowing through the second flow passage.

In this case, on the one hand, if the evaporation pressure is too low or the superheat of the refrigerant at the outlet of the evaporator 5 is high, the flow cross section of the high-pressure side flow passage of the expansion valve 17a is increased, i.e., opened further. On the other hand, the flow cross-sectional area of the high pressure side flow path of the expansion valve 17a is reduced if the vapor pressure is too high or the superheat of the refrigerant at the outlet of the evaporator 5 is too low, ie it is further closed.

The increase in the flow cross-sectional area of the high-pressure side flow passage of the expansion valve 17a is accompanied by an increase in the intermediate pressure level of the refrigerant in the separator 8a and thus accompanied by a decrease in the vapor mass fraction of the refrigerant in the separator 8a. It causes a decrease in the bypass mass flow of the refrigerant by the second flow path 7. Reduction of the bypass mass flow of the refrigerant causes a reduction in the load of the compression component 4b of the expansion-compression device 4, which in turn is relatively less refrigerant when flowing through the expansion component 4a of the expansion-compression device 4. Causing expansion, consequently the low pressure level and evaporation pressure of the refrigerant are raised, the main mass flow of refrigerant passing through the first flow path 6 is increased, and thus the refrigerant at the outlet of the evaporator 5 Superheat decreases.

The decrease in the flow cross-sectional area of the high pressure side flow passage of the expansion valve 17a is due to the increase in the vapor mass fraction of the refrigerant in the separator 8a, thereby reducing the intermediate pressure level of the refrigerant in the separator 8a and thus the second This results in an increase in the bypass mass flow of refrigerant through the flow path 7. Increasing the bypass mass flow of the refrigerant causes an increase in the load of the compression component 4b of the expansion-compression device 4, which in turn is relatively large refrigerant when flowing through the expansion component 4a of the expansion-compression device 4. Causing expansion, and consequently the low pressure level and evaporation pressure of the coolant are reduced, the main mass flow of coolant through the first flow path 6 is reduced, and thus the coolant at the outlet of the evaporator 5 Superheat increases.

4 shows a fourth refrigerant circuit 1d having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The fourth refrigerant circuit 1d likewise has a first flow path 6 and a second flow path 7 and a thermostatic expansion valve 17a, wherein the first flow path and the second flow path are respectively It extends from the branching point 8 formed as the separator 8a to the inlet 9. Therefore, the fourth refrigerant circuit 1d is formed similarly to the third refrigerant circuit 1c of FIG. 3. The refrigerant circuits 1c and 1d are similar in function. In addition, the same components of the refrigerant circuits 1c and 1d have been provided with the same reference numerals.

The main difference between the third refrigerant circuit 1c of FIG. 3 and the fourth refrigerant circuit 1d of FIG. 4 is in the formation of the third flow path 14 as a bypass bypassing the circumference of the expansion-compression device 4. In this case, the third flow path extends from the branch point 13 to the inlet 15. Inside the third flow path 14 an additional expansion member 19 is provided. The further expansion member 19, which is preferably formed as an expansion valve, can be designed not only as an electronic expansion valve but also as a thermostatic valve. The branch point 13 is arranged between the first heat exchanger 3 and the high pressure side of the thermostatic expansion valve 17a, while the inlet 15 is in the first flow path 6 an expansion-compression device ( Formed between the expansion component 4a of the 4) and the second heat exchanger 5, so that the expansion-compression device 4 is particularly necessary to avoid cycle operation in certain operating modes in the low load range. It can be stopped.

The total mass flow of refrigerant is expanded from the high pressure level directly to the low pressure level when flowing through the further expansion member 19 and fed to the evaporator 5. In this case, the thermostatic expansion valve 17a is provided with a switch-off function so that the high pressure side flow path of the thermostatic expansion valve 17a and the separator 8a can be kept closed. According to an alternative embodiment not shown in the figure, an additional shut-off valve is provided before or after the thermostatic expansion valve 17a in the flow direction of the refrigerant in the high-pressure side flow path. During operation of the refrigerant circuit 1d in which the third flow path 14 is closed, the refrigerant expands from the high pressure level to the intermediate pressure level when flowing through the high pressure side flow passage of the thermostatic expansion valve 17a, thereby separating the separator 8a. Is supplied.

In order to avoid refrigerant / oil movement into the compression component 4b of the expansion-compression device 4 or unintentional reverse overflow of the refrigerant to the high pressure level, a check member 16 is likewise present in the second flow path 7. ) Is provided. In particular, a check member formed as a check valve is arranged between the compression component 4b and the inlet 9. An active shut-off valve or an electronic expansion valve may alternatively be provided in place of the check member 16, which is configured to open the entire flow cross section to prevent pressure loss.

In FIG. 5A there is shown a fifth refrigerant circuit 1e having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The fifth refrigerant circuit 1e likewise has a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path are each at the inlet 9 at the branch point 8. ) And run parallel to each other. The branch point 8 is arranged immediately after the first heat exchanger 3 in the flow direction of the refrigerant. The fifth refrigerant circuit 1e is also formed with an internal heat exchanger 21, which thermally connects the first flow path 6 and the second flow path 7 to each other.

Within the first flow path 6, the flow direction of the refrigerant is in the high pressure side of the internal heat exchanger 21, the expansion component 4a of the expansion-compression device 4, the second heat exchanger 5 which acts as an evaporator. And a compressor 2 which operates as the main compressor of the refrigerant circuit 1e. The liquid refrigerant flowing into the first flow path 6 is supercooled when flowing through the high pressure side of the internal heat exchanger 21 and low pressure at a high pressure level when flowing through the expansion component 4a of the expansion-compression device 4. At the level, expands operably to the two phase region and is fed to the evaporator 5. When flowing through the evaporator 5, the liquid portion of the refrigerant evaporates while absorbing heat. The refrigerant is then sucked by the compressor 2 and compressed to a high pressure level.

In the flow direction of the refrigerant in the second flow path 7 formed as a bypass of the first flow path 6, the expansion member 20, the intermediate pressure side of the internal heat exchanger 21 and the expansion-compression device ( The compression component 4b of 4) is arranged. The liquid refrigerant flowing into the second flow path 7 preferably expands into a two-phase region from the high pressure level to the intermediate pressure level when flowing through the expansion member 20 formed as an expansion valve, so that the middle of the internal heat exchanger 21 can be obtained. It is supplied to the pressure side. When flowing through the intermediate pressure side of the internal heat exchanger 21, the liquid portion of the refrigerant evaporates while absorbing heat. Subsequent compression of the compression component 4b of the expansion-compression device 4 from the intermediate pressure level to the high pressure level.

The internal heat exchanger 21 refers to an in-circuit heat exchanger used for heat transfer between the high pressure level refrigerant guided through the first flow path 6 and the intermediate pressure level refrigerant guided through the second flow path 7. The internal heat exchanger 21 is preferably supplied with a refrigerant in a countercurrent fashion.

At the inlet 9, the main mass flow guided through the first flow path 6 and the bypass mass flow guided through the second flow path 7 are mixed and guided to the first heat exchanger 3. When flowing through the first heat exchanger 3, which acts as a condenser / gas cooler, the refrigerant liquefies while releasing heat. The refrigerant circuit 1e is closed.

The state and change of state of the refrigerant within the refrigerant circuit 1e are shown in FIG. 5B in a pressure-enthalpy diagram for subcritical operation of the refrigerant circuit 1e. The reference numerals respectively show the state change when flowing through the components of the refrigerant circuit 1e or the state at a specific point of the refrigerant circuit 1e.

Bypass mass flow of the refrigerant in the formation of the fifth refrigerant circuit 1e is directed to the outlet of the condenser / gas cooler 3 in the second flow path 7 before being subsequently guided to the internal heat exchanger 21. It can be adjusted by means of an expansion member 20 arranged after the arranged branching point 8. The main mass flow of the refrigerant flowing through the first flow path 6 inside the internal heat exchanger 21 is at a medium pressure level at a higher temperature than the bypass mass flow having a high pressure level and, consequently, a medium pressure level. During the subcritical operation of the refrigerant circuit 1e, the heat mass inside the internal heat exchanger 21 increases the vapor mass fraction of the bypass mass flow or overheats the bypass mass flow, In the critical operation the bypass mass flow is heated, while the main mass flow is condensed and supercooled in some cases during the supercritical operation of the refrigerant circuit 1e or cooled in the supercritical operation of the refrigerant circuit 1e. The refrigerant circuit 1e with the internal heat exchanger 21 is particularly advantageous for the operation of the refrigerant circuit 1e in the supercritical region, because the high pressure level of the refrigerant is an expansion component of the expansion-compression device 4. This is because it does not have to be forcibly reduced to an intermediate pressure level first to enable phase separation before entering into 4a. This maintains a higher likelihood of kinetic energy that can be recovered by the expansion-compression device 4.

The bypass mass flow of the refrigerant is intermediate pressure by the expansion member 20 at the inlet leading to the compression component 4b of the expansion-compression device 4 or according to the pressure and / or temperature of the refrigerant at the outlet of the evaporator 5. The level is adjusted. The pressure and / or temperature of the main mass flow of refrigerant at the outlet of the evaporator 5 is determined by the sensor 11. According to an alternative embodiment, the pressure and / or temperature of the bypass mass flow of the refrigerant is detected by the sensor 12 at the inlet leading into the compression component 4b of the expansion-compression device 4. In this case the sensors 11, 12 are each formed as a connected pressure sensor / temperature sensor or as a pressure sensor or as a temperature sensor.

On the one hand, in particular, the load on the expansion component 4a of the expansion-compression device 4 is reduced, thereby increasing the main mass flow of refrigerant passing through the evaporator 5 and expanding the expansion component of the expansion-compression device 4. In order to reduce the throttle effect of 4a, when the pressure of the main mass flow of the refrigerant at the outlet of the evaporator 5 is too low or the superheat of the refrigerant at the outlet of the evaporator 5 is too high, the expansion member 20 Flow cross sectional area ie the expansion member 20 is further closed. On the other hand, in particular, because the load on the expansion component 4a of the expansion-compression device 4 is increased, it reduces the main mass flow of refrigerant passing through the evaporator 5 and expands the expansion-compression device 4. In order to increase the throttle effect of the component 4a, if the pressure of the main mass flow of the refrigerant at the outlet of the evaporator 5 is too high or the superheat of the refrigerant at the outlet of the evaporator 5 is too low, the expansion member ( The flow cross-sectional area of 20, ie the expansion member 20 is further opened.

The control strategy cited can be applied to control by the sensor 12, in which case the pressure of the bypass mass flow of refrigerant at the outlet of the internal heat exchanger 21 is too low or at the outlet of the internal heat exchanger 21. If the superheating degree is too high, the flow cross section of the expansion member 20 increases, that is, the expansion member 20 is further opened.

Increasing the flow cross-sectional area of the inflation member 20 increases the bypass mass flow through the second flow path 7 and, in addition, the inflation component 4a as well as the compression component 4b of the inflation-compression device 4. ), Which in turn expands the refrigerant more in the flow of the expansion component 4a of the expansion-compression device 4, as a result of which the low pressure level and the evaporation pressure of the refrigerant are reduced and the first flow path 6 The main mass flow of the refrigerant passing through) decreases, and the superheat of the refrigerant at the outlet of the evaporator 5 is increased.

Reducing the flow cross-sectional area of the expansion member 20 reduces the bypass mass flow through the second flow path 7 and, in addition, the expansion component 4a as well as the compression component 4b of the expansion-compression device 4. ), Which in turn causes less expansion of the refrigerant upon perfusing the expansion component (4a) of the expansion-compression device (4), as a result of which the low pressure level and the evaporation pressure of the refrigerant rise and the first flow path (6) The main mass flow of the refrigerant passing through) increases, and the superheat of the refrigerant at the outlet of the evaporator 5 is reduced.

The kinetic energy of the main mass flow of the refrigerant withdrawn when flowing through the expansion component 4a of the expansion-compression device 4 receives the bypass mass flow guided through the compression component 4b of the expansion-compression device 4. Used to compress. The expansion component 4a and the compression component 4b of the expansion-compression device 4 can then be arranged on a common mechanical shaft, so that the kinetic energy is transferred directly between the components.

6a shows a sixth refrigerant circuit 1f having a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The sixth refrigerant circuit 1f likewise has a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path each have an inlet 9 at a branch point 8. ) And are thermally connected to each other via an internal heat exchanger (21). Therefore, the sixth refrigerant circuit 1f is formed similarly to the fifth refrigerant circuit 1e of FIG. 5A. The refrigerant circuits 1e and 1f are similar in function. In addition, the same components of the refrigerant circuits 1e and 1f have been provided with the same reference numerals.

The main difference between the fifth refrigerant circuit 1e of FIG. 5A and the sixth refrigerant circuit 1f of FIG. 6A is a bypass bypassing the expansion-compression device 4, which extends from the branch point 13 to the inlet 15. In the formation of the third flow path 14. In this case the branching point 13 of the third flow path 14 disposed between the first flow path 6 and the second flow path 7 is a three-way valve with an expansion function and in particular an expansion member ( 13b), in particular as a 3 / 2-way valve or as a 3 / 3-way valve. According to an alternative embodiment not shown in the figures, instead of the three-way valve, two separate controllable valves are provided, in particular an expansion valve and a shutoff valve. The inlet 15 is arranged in the first flow path 6 between the expansion component 4a of the expansion-compression device 4 and the second heat exchanger 5, so that the expansion-compression device 4 ) Can be shut down if necessary.

The expansion-compression device 4 can thus be deactivated, in particular to avoid cycle operation in certain operating modes of the low load range. In this case, the total mass flow of the refrigerant is expanded from the high pressure level directly to the low pressure level and supplied to the evaporator 5 when flowing through the branch point 13 or the expansion member 13b formed as a three-way valve with an expansion function. A particular mode of operation is also shown in FIG. 6B where the pressure-enthalpy diagram for the sub-threshold operation of the sixth refrigerant circuit 1f is shown, wherein the pressure-enthalpy diagram is shown in broken lines. The first flow path 6 with the internal heat exchanger 21 and the region of the expansion component 4a of the expansion-compression device 4 and the second flow path 7, in particular the expansion member 20, are closed. .

The branching point 13 formed as a three-way valve with expansion function 13 and as expansion member 13b can optionally open or close the third flow path 14 in the direction of the evaporator 5 and Alternatively, the first flow path 6 can be opened or closed in the direction of the internal heat exchanger 21. In this case, the branching point 13 can be at least partially open in both directions in order to switch slowly between the operating modes of the refrigerant circuit 1f with or without the expansion-compression device 4 operating.

In order to avoid refrigerant / oil movement into the compression component 4b of the expansion-compression device 4 or unintentional reverse overflow of the refrigerant to a high pressure level, a check member 16 is provided in the second flow path 7. Is provided. In particular, a check member 16 formed as a check valve is arranged between the compression component 4b and the inlet 9. An active shut-off valve or an electronic expansion valve may alternatively be provided in place of the check member 16, which is configured to open the entire flow cross section to prevent pressure loss.

7 shows a seventh refrigerant circuit 1g with a compressor 2, a first heat exchanger 3, an expansion-compression device 4 and a second heat exchanger 5. The seventh refrigerant circuit 1g likewise has a first flow path 6 and a second flow path 7, wherein the first flow path and the second flow path each have an inlet 9 at a branch point 8. ) And are thermally connected to each other via an internal heat exchanger (21). Therefore, the seventh refrigerant circuit 1g is formed similarly to the fifth refrigerant circuit 1e of Fig. 5A. The refrigerant circuits 1e, 1f, 1g are similar in function. In addition, the same components of the refrigerant circuits 1e, 1f, 1g have been provided with the same reference numerals.

The main difference between the fifth refrigerant circuit 1e of FIG. 5A and the seventh refrigerant circuit 1g of FIG. 7 is the formation of a thermostatic dosing valve as an expansion member 17b for the refrigerant flowing through the second flow path 7. In which case the expansion member is in the sensor 11 or alternatively in the second flow path 7 disposed at the outlet of the evaporator 5 in the active expansion member 20 and in the first flow path 6. In place of the sensor 12 of the fifth refrigerant circuit 1e, which is provided at the inlet leading into the compression component 4b of the expansion-compression device 4.

The thermostatic dosing valve 17b disposed at the outlet of the evaporator 5 on the low pressure side with the first flow passage is in particular flowed through by the gaseous refrigerant, so that the pressure of the refrigerant inside the dosing valve 17b or According to the temperature, the closing member 18b formed as a tappet having a spherical head is moved. The thermostatic dosing valve 17b is disposed between the branch point 8 of the first flow path 6 and the second flow path 7 and the internal heat exchanger 21 on the high pressure side having the second flow path. The head of the closing member 18a is arranged in such a way that it forms the flow cross sectional area of the high pressure side flow passage of the dosing valve 17b and influences the high pressure side perfusion to be interrupted or continuously adjusted. When flowing through the second flow passage 7 the high pressure level refrigerant is expanded to an intermediate pressure level.

As a result, the thermostatic dosing valve 17b which satisfies the function of the expansion valve has a high pressure side mass flow of the refrigerant compared to the expansion valve 17a of the refrigerant circuits 1c and 1d according to FIGS. 3 and 4. It is distinguished by adjusting in an opposite manner to the use of the expansion valve 17a.

In this case, on the one hand, if the evaporation pressure is too low or the superheat of the refrigerant at the outlet of the evaporator 5 is high, the flow cross section of the high pressure side flow passage of the dosing valve 17b is reduced, i. On the other hand, if the vapor pressure is too high or if the superheat of the refrigerant at the outlet of the evaporator 5 is too low, the flow cross section of the high pressure side flow path of the dosing valve 17b is increased, i.e. opened further.

Increasing the flow cross-sectional area of the high pressure side flow passage of the dosing valve 17b increases the bypass mass flow of the refrigerant passing through the second flow path 7 and, together with the compression component 4b of the expansion-compression device 4. Causing a load to expand, which in turn expands the refrigerant more when flowing through the expansion component 4a of the expansion-compression device 4, resulting in a lower pressure level and evaporation pressure of the refrigerant and the first flow path 6 The main mass flow of refrigerant passing through is reduced, thereby increasing the degree of superheat of the refrigerant at the outlet of the evaporator 5.

The reduction in the flow cross-sectional area of the high pressure side flow passage of the dosing valve 17b reduces the bypass mass flow of the refrigerant passing through the second flow path 7 and thus the compression component 4b of the expansion-compression device 4. Causing a load on the refrigerant, which in turn leads to less expansion of the refrigerant when flowing through the expansion component 4a of the expansion-compression device 4, resulting in a lower pressure level and evaporation pressure of the refrigerant and the first flow path 6 The main mass flow of the refrigerant passing through increases, and thus the superheat of the refrigerant at the outlet of the evaporator 5 decreases.

8 and 9 show an eighth refrigerant circuit 1h or a ninth refrigerant circuit 1i having a compressor 2, a first heat exchanger 3, an expansion-compression device 4, and a second heat exchanger 5. Shows. The refrigerant circuits 1h and 1i likewise have a first flow path 6 and a second flow path 7 and a thermostatic dosing valve 17b, wherein the first flow path and the second flow path are Each extends from the branch point 8 to the inlet 9 and is thermally connected to each other via an internal heat exchanger 21. Therefore, the refrigerant circuits 1h and 1i are formed similarly to the seventh refrigerant circuit 1g of FIG. 7. The refrigerant circuits 1g, 1h, 1i are similar in function. In addition, the same components of the refrigerant circuits 1g, 1h, 1i are provided with the same reference numerals.

The main difference between the seventh refrigerant circuit 1g of FIG. 7, the eighth refrigerant circuit 1h of FIG. 8, and the ninth refrigerant circuit 1i of FIG. 9 is the third flow as a bypass of the expansion-compression device 4. In the formation of the path 14, the third flow path extends from the branch point 13 to the inlet 15.

The branch point 13 of the third flow path 14, which is arranged between the first heat exchanger 3 and the branch point 8 of the first flow path 6 and the second flow path 7, is formed in accordance with FIG. 8. In the embodiment of the eight refrigerant circuit 1h, it is formed as a three-way valve with an expansion function and specifically as an expansion member 13b, in particular as a 3 / 2-way valve or a 3 / 3-way valve. In the embodiment of the ninth refrigerant circuit 1i according to FIG. 9 as compared to the refrigerant circuit 1h of FIG. 8, two controllable valves 22 separately in addition to the branch point 13 as the expansion member 13b instead of the three-way valve 22. 23, in particular an expansion valve 22 and a shutoff valve 23 are provided. The expansion member 22 formed as the expansion valve 22 is preferably formed as a thermostatic expansion valve with a blocking function, not shown in the figure, in which the expansion valve flows out of the evaporator 5 at the suction side. Refrigerant is supplied.

The inlet 15 is arranged in the first flow path 6 between the expansion component 4a of the expansion-compression device 4 and the second heat exchanger 5, so that the expansion-compression device 4 ) Can be shut down if necessary. The expansion-compression device 4 can thus be deactivated, in particular to avoid cycle operation in certain operating modes of the low load range.

In this case, the total mass flow of the refrigerant flows through the branch point 13 or the expansion member 13b formed as a three-way valve with the expansion function of the refrigerant circuit 1h according to FIG. 8 or the refrigerant circuit according to FIG. When flowing through the expansion valve 22 of 1i) it is expanded from the high pressure level directly to the low pressure level and supplied to the evaporator 5. The first flow path 6 with the internal heat exchanger 21 and the region of the expansion component 4a of the expansion-compression device 4 and the second flow path 7 are each closed, in this case for example The shutoff valve 23 of the refrigerant circuit 1i according to FIG. 9 is closed.

A branch circuit 13 of the refrigerant circuit 1h according to FIG. 8 or a refrigerant circuit according to FIG. 9 formed as a three-way valve with an expansion function, in particular as a 3 / 3-way valve and as an expansion member 13b. By branching point 13 with valves 22 and 23 of 1i, each of the third flow path 14 can optionally be opened or closed in the direction of evaporator 5, or the first flow path ( 6) may be opened or closed in the direction of the internal heat exchanger 21. The mass flow of the refrigerant at the high pressure level actually passes through the three-way valve of the refrigerant circuit 1h according to FIG. 8 or the shutoff valve 23 of the refrigerant circuit 1i according to FIG. The mass flow to the path 14 and the evaporator 5 expands to a low pressure level. In this case the expansion member 13b of the refrigerant circuit 1h according to FIG. 8 or the figure for slowly switching between the operating modes of the individual refrigerant circuits 1h, 1i with or without the expansion-compression device 4 in operation. The branch point 13 with the valves 22, 23 of the refrigerant circuit 1i according to 9 can be at least partially open in both directions. The thermostat with a shutoff function in order to close the second flow path 7, in particular the high-pressure side region of the flow path 7, with respect to the thermostatic dosing valve 17b and thereby prevent uncontrolled flow of refrigerant. The static dosing valve 17b is formed. According to an alternative embodiment not shown in the figures, an additional shut-off valve is arranged in front of or behind the thermostatic dosing valve 17b in the flow direction of the refrigerant in the high-pressure side flow path.

In order to avoid refrigerant / oil movement into the compression component 4b of the expansion-compression device 4 or unintentional reverse overflow of the refrigerant to a high pressure level, a check member 16 is provided in the second flow path 7. Is provided. In particular, a check member 16 formed as a check valve is arranged between the compression component 4b and the inlet 9. Instead of the check member 16, an alternatively active shutoff valve or electronic expansion valve may be provided.

The advantage of the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, on the one hand, is particularly advantageous when the air conditioning system is operating in a chiller mode for cooling the incoming air for the cabin. (5) When the main mass flow passing through is constant, it is also referred to as evaporation enthalpy, also referred to as phase separation in separator 8a or heat transfer between the main mass flow and the bypass mass flow in evaporator 5. Higher cooling capacity appears, which in turn realizes higher cooling capacity. Constant main mass flow of refrigerant is achieved by the compressor 2 operating at a constant rotational speed and a constant stroke volume. On the other hand the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i are constant when operating at low main mass flows, for example due to the relatively low rotational speed of the compressor 2. Cooling capacity can be provided. Both modes of operation increase the operating efficiency of the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i or the air conditioning system.

In addition, the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i are heat exchangers in which the refrigerant can be further supplied simultaneously and / or continuously and operate as a condenser / gas cooler or evaporator. For example, one or more additional internal heat exchangers and / or additional expansion members. In addition, the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i may have one or more high pressure collectors on the high pressure side, one or more low pressure collectors or intermediates, also referred to as accumulators on the low pressure side. One or more refrigerant collectors of pressure level may be provided.

In addition, in order to further improve the controllability of the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g A further expansion valve can be provided after the compression component 4b of the expansion-compression device 4 in the flow direction of the refrigerant, in particular within the second flow path 7, 1h, 1i.

In this case the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i and the operating modes can be considered in the case of all refrigerants which carry out a phase change from liquid to gas phase on the low pressure side. . On the high pressure side, the refrigerant releases the heat absorbed by the gas cooling or condensation, in some cases by subcooling, to the heat sink, respectively. Refrigerants include, in particular, natural materials such as R744, R717, flammable materials such as R290, R600, R600a, and the like, chemicals such as R134a, R152a, R1234yf, R32, R404A, and mixtures thereof. .

1a to 1i: refrigerant circuit
2: compressor
3: first heat exchanger, condenser / gas cooler
4: expansion-compression device
4a: expansion component of the expansion-compression device 4
4b: compression component of expansion-compression device 4
5: second heat exchanger, evaporator
6: first flow path
7: second flow path
8, 13: fork
8, 8a: separator
9, 15: entrance
10: inflatable member
11, 12: sensor
13a, 13b: expansion member
14: third flow path
16: check member
17a: expansion member, thermostatic expansion valve
17b: expansion member, thermostatic dosing valve
18a, 18b: closure member
19, 20: expansion member
21: third heat exchanger, internal heat exchanger
22: valve, thermostatic expansion valve, expansion member
23: valve, shut-off valve

Claims (33)

One or more compressors 2, a first heat exchanger 3 operable as a condenser / gas cooler of the refrigerant, an expansion-compression device 4 having an expansion component 4a and a compression component 4b and an evaporator of the refrigerant As a refrigerant circuit 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i for an air conditioning system of an automobile, having a second heat exchanger 5 possible,
The first flow path 6 and the second flow path 7 are each formed so that the refrigerants can be supplied in parallel to each other in such a way that they extend from the branch point 8 to the inlet 9, respectively. And the inlet 9 is arranged between the compressor 2 and the first heat exchanger 3, the expansion component 4a, the second in the flow direction of the refrigerant in the first flow path 6. A heat exchanger (5) and a compressor (2) are formed, and the compression component (4b) is formed in the second flow path (7), refrigerant circuits (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i). The expansion-compression device 4 according to claim 1, wherein the kinetic energy converted from the expansion of the refrigerant by the expansion component 4a is transferred directly to the compression component 4b for compressing the refrigerant. Refrigerant circuit (1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i), characterized in that the expansion component (4a) and the compression component (4b) are mechanically connected to each other. 2. The first heat exchanger as claimed in claim 1, wherein the branch point (8) is formed as a separator (8a), at which point the refrigerant has a lower pressure level than at the outlet of the first heat exchanger (3). A refrigerant circuit (1a, 1b, 1c, 1d), characterized in that an apparatus for expanding the refrigerant is disposed between the (3) and the branch point (8). A refrigerant circuit (1a) according to claim 3, characterized in that the device for expanding the refrigerant is formed as expansion members (10, 13a), in particular as expansion valves or as valves with expansion functions, in particular as three-way valves. , 1b). 2. The branch point (8) according to claim 1, wherein the branch point (8) is formed as a T-shaped member such that the pressure level of the refrigerant at the outlet of the first heat exchanger (3) corresponds to the pressure level of the refrigerant after flowing through the branch point (8). Refrigerant circuits 1e, 1f, 1g, 1h and 1i, which are arranged at the outlet of the heat exchanger 3. 6. The internal heat exchanger (21) is formed, wherein the internal heat exchanger is arranged in such a way as to thermally connect the first flow path (6) and the second flow path (7) to each other. , Refrigerant circuits 1e, 1f, 1g, 1h, 1i. The internal heat exchanger (21) according to claim 6, characterized in that it is arranged in the first flow path (6) between the branch point (8) and the expansion component (4a) of the expansion-compression device (4). Refrigerant circuits 1e, 1f, 1g, 1h and 1i. The internal heat exchanger (21) is arranged in the second flow path (7) between the branch point (8) and the compression component (4b) of the expansion-compression device (4). Refrigerant circuit (1e, 1f, 1g, 1h, 1i), characterized in that a device for expanding the refrigerant is arranged in front of the internal heat exchanger (21) in the flow direction. The refrigerant circuit (1e, 1f) according to claim 8, characterized in that the device for expanding the refrigerant is formed as an expansion member (20), in particular an expansion valve. The refrigerant circuit (1a, 1b, 1e, 1f) according to claim 1, characterized in that a sensor (11) for determining the state of the refrigerant is arranged at an outlet of the refrigerant of the second heat exchanger (5). . The refrigerant circuit (1a, 1b) according to claim 1, characterized in that a sensor (12) is arranged at the inlet leading to the compression component (4b) of the expansion-compression device (4) for determining the state of the refrigerant. , 1e, 1f). 4. A device according to claim 3, wherein said device for expanding said refrigerant is formed as a thermostatic expansion valve (17a), said thermostatic expansion valve having a low pressure side first flow passage and a high pressure side second flow passage. The flow passage is arranged in the first flow path 6 at the outlet of the second heat exchanger 5, and the second flow passage is disposed between the first heat exchanger 3 and the branch point 8. Refrigerant circuits 1c and 1d. 4. A device according to claim 3, wherein said device for expanding said refrigerant is formed as a thermostatic dosing valve (17b), said thermostatic dosing valve having a low pressure side first flow passage and a high pressure side second flow passage. A flow passage is at the outlet of the second heat exchanger 5 in the first flow path 6 and the second flow passage is internal heat exchange with the branch point 8 in the second flow path 7. Refrigerant circuits (1g, 1h, 1i), characterized in that arranged between the groups (21). The thermostatic expansion valve (17a) or the thermostatic dosing valve (17b) is formed with a closing member (18a, 18b) movably supported, wherein the closing member is Configured to continuously change the flow cross-sectional area of the second flow passage between two final positions within the first flow passage, wherein the refrigerant expands when flowing through the second flow passage. , 1d, 1g, 1h, 1i). 13. The thermostatic expansion valve (17a) according to claim 12, wherein the thermostatic expansion valve (17a) increases the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the first flow passage is too low or the superheat degree is too high. Refrigerant circuit (1c, 1d), characterized in that configured to reduce the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the flow passage is too high or the superheat is too low. 14. The thermostatic dosing valve (17b) according to claim 13, wherein the thermostatic dosing valve (17b) reduces the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the first flow passage is too low or the superheat of the refrigerant is too large, Refrigerant circuit (1g, 1h, 1i), characterized in that configured to increase the flow cross-sectional area of the second flow passage if the pressure of the refrigerant in the first flow passage is too high or the superheat is too low. . 3. The third flow path (14) according to claim 1, wherein a third flow path (14) is formed extending from the branch point (13) to the inlet (15), the inlet (15) being the expansion- within the first flow path (6). A refrigerant circuit (1b, 1d, 1f, 1h, 1i), characterized in that it is arranged between the expansion component (4a) of the compression device (4) and the second heat exchanger (5). 18. The refrigerant circuit (1b) according to claim 17, characterized in that the branching point (13) of the third flow path (14) is formed as a three-way valve with expansion members (13a, 13b) and at least one expansion function. 1f, 1h). 19. The first heat exchanger (3) and the first heat exchanger (3) according to claim 18, wherein the branching point (13) of the third flow path (14) formed as a three-way valve and one or more expansion members (13a, 13b) with at least one expansion function. A refrigerant circuit (1b, 1h), characterized in that it is arranged between the flow path (6) and the branch point (8) of the second flow path (7). The branch points 13, 13b of the third flow path 14, formed as a three-way valve with at least one inflation function, are internal to the branch point 8 in the first flow path 6. A refrigerant circuit (1f), characterized in that arranged between the heat exchangers (21). 18. Refrigerant circuit (1d, 1i) according to claim 17, characterized in that an expansion member (19, 22) is formed in said third flow path (14). 2. The refrigerant circuit according to claim 1, characterized in that an expansion member is arranged after the compression component 4b of the expansion-compression device 4 in the flow direction of the refrigerant in the second flow path 7. 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i). 23. Operating the refrigerant circuits 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i for an automotive air conditioning system according to any one of claims 1 to 13 and 15 to 22. As a method for
The total mass flow of refrigerant is passed through the first flow path 6 and the bypass mass flow through the second flow path 7 at the branching points 8 of the flow paths 6, 7. Dividing into steps,
Expanding the refrigerant of the main mass flow guided through the first flow path 6 to a low pressure level when flowing through the expansion component 4a of the expansion-compression device 4,
Compressing the refrigerant of the bypass mass flow guided through the second flow path 7 to a high pressure level when flowing through the compression component 4b of the expansion-compression device 4, wherein the expansion component 4a ) The kinetic energy converted when the refrigerant of the main mass flow expands during perfusion is used to compress the refrigerant of the bypass mass flow when flowing through the compression component 4b, and
A combination of a refrigerant of the main mass flow and a refrigerant of the bypass mass flow which is compressed at a high pressure level in the compressor 2 at the inlet 9 of the flow paths 6, 7, Way. The method of claim 23, wherein the refrigerant in the bypass mass flow is compressed from a medium pressure level to a high pressure level. 24. The bypass according to claim 23, wherein the refrigerant of the total mass flow expands from a high pressure level to an intermediate pressure level and consists of a main mass flow consisting of liquid refrigerant and a refrigerant in vapor state at a branch point 8 formed as a separator 8a. Characterized in that it is divided into mass flows. 26. The bypass mass according to claim 25, wherein the refrigerant in the main mass flow guided through the first flow path (6) is expanded from a medium pressure level to a low pressure level and guided through the second flow path (7). Wherein the refrigerant in the flow is compressed from a medium pressure level to a high pressure level. 24. The method of claim 23, wherein the total mass flow of the high pressure level refrigerant is divided into a main mass flow and a bypass mass flow, wherein the refrigerant of the main mass flow is from a high pressure level to a low pressure level and the refrigerant of the bypass mass flow is a high pressure level. Inflated to an intermediate pressure level. The refrigerant of the main mass flow of the high pressure level according to claim 27 when flowing through an internal heat exchanger (21) thermally connecting the first flow path (6) and the second flow path (7). And cools while releasing heat to the refrigerant in the pass mass stream, wherein the refrigerant in the bypass mass stream at the intermediate pressure level evaporates while absorbing heat. The method of claim 24, wherein the intermediate pressure level of the bypass mass flow of the refrigerant is adjusted such that the medium pressure level refrigerant is in the two phase region. 30. The medium pressure level of the refrigerant according to claim 29, wherein the intermediate pressure level of the refrigerant is adjusted so that the refrigerant has a state in the two-phase region when introduced into the separator (8a). And the ratio of bypass mass flow is set. 24. The expansion-compression device (4) according to claim 23, wherein the total mass flow or bypass mass flow of the refrigerant is dependent on the pressure and / or temperature of the refrigerant at the outlet of the second heat exchanger (5) acting as an evaporator or Method according to the pressure and / or temperature of the refrigerant at the inlet to the compression component (4b) of the. 32. The heat exchanger according to claim 31, wherein the total mass flow of the refrigerant is regulated by expansion members (10, 13a, 17) formed in front of the branch point (8) in the direction of flow of the refrigerant and at the outlet of the heat exchanger (5) operating as an evaporator. When the pressure of the refrigerant in the main mass flow is low or the degree of superheat is high, the flow cross-sectional areas of the expansion members 10, 13a and 17a are increased, and the pressure of the refrigerant in the main mass flow is increased at the outlet of the heat exchanger 5. A high or low degree of superheat is characterized in that the flow cross section of the expansion member (10, 13a, 17a) is reduced. 32. The outlet of the heat exchanger (5) according to claim 31, wherein the bypass mass flow of the coolant is regulated by expansion members (20, 17b) formed in front of the internal heat exchanger (21) in the flow direction of the coolant, and operates as an evaporator. When the pressure of the refrigerant of the main mass flow is low or the superheat degree is high, the flow cross-sectional areas of the expansion members 20 and 17b decrease, and the pressure of the refrigerant of the main mass flow is high at the outlet of the heat exchanger 5. Or low superheat, the flow cross-sectional area of the expansion member (20, 17b) is increased.

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