JP4870867B2 - Air conditioning circuit especially for automobiles - Google Patents

Description

[0001]
[Technical field to which the invention belongs]
The present invention particularly relates to an air conditioning circuit for an automobile vehicle.
[0002]
In conventional air conditioning circuits, a cooling fluid, generally a compound containing fluorine, that exists as two different phases, a gas phase and a liquid phase, flows. Such a circuit mainly includes a compressor, a condenser, a pressure reducing device, and an evaporator, and the cooling fluid flows in that order.
[0003]
The cooling fluid in the gas phase is compressed by the compressor, then changes to the liquid phase in the condenser through which the air flow passes, then decompressed to a low pressure by the decompressor and finally in the evaporator. It changes to the vapor phase, the flow of air passes through the evaporator and so on. Within the evaporator, the cooling fluid absorbs the heat of the air stream, and this air stream is thus cooled, for example to be sent into the living space of a motor vehicle.
[0004]
Furthermore, since the cooling fluid exists not as two phases as in conventional air conditioning circuits, but only as one phase, ie the gas phase, it follows a cycle called “supercritical pressure”, for example carbon dioxide ( Air conditioning circuits that operate with natural cooling fluids such as CO2) are also known.
[0005]
An air conditioning circuit that operates according to a supercritical pressure cycle mainly includes a compressor, a gas cooler (or called a “gas cooler”), an internal heat exchanger, a pressure reducing device, an evaporator, and an accumulator. In this way, instead of conventional capacitors, a gas cooler is used to dissipate heat under variable high pressure.
[0006]
Conventional air conditioning circuits are usually equipped with a cylinder installed between the compressor and the condenser, or an accumulator installed between the evaporator and the compressor, which controls the supercooling of the cooling fluid at the outlet of the condenser. Can not do it.
[0007]
In order to eliminate this inconvenience, various techniques for controlling and improving supercooling have been proposed.
[0008]
The first solution is to forcibly generate supercooling by providing a third heat exchanger after the cylinder. In this way, an assembly of a condenser, cylinder and supercooling module can be formed and combined into a single module.
[0009]
In the second solution, supercooling is forcibly caused by using a decompression device (internal or external control type) installed between the cylinder and the condenser.
[0010]
The third solution uses an internal heat exchanger that cools the hot liquid at the outlet of the condenser by cold air at the outlet of the evaporator.
[0011]
The second solution is particularly suitable for operating according to a supercritical pressure cycle, in particular with a natural cooling fluid, in particular carbon dioxide.
[0012]
All these conventional air conditioning circuits have the disadvantage of requiring a large number of connections, in particular between the various components of the circuit.
[0013]
The present invention is particularly aimed at overcoming such inconveniences.
[0014]
Therefore, the present invention is an air conditioning circuit of the type defined at the beginning, in which a condenser has an internal heat exchange through a first outlet connected to the first branch of the internal heat exchanger and a second decompression device. A second outlet connected to the second branch of the heat exchanger, the first branch of the internal heat exchanger is connected to a circuit decompressor, and the second branch of the internal heat exchanger is The condenser, the internal heat exchanger and the second pressure reducing device connected upstream of the compressor are arranged in a single module that can be installed in the circuit.
[0015]
Thus, according to the present invention, the condenser, the internal heat exchanger, and the second pressure reducing device can be incorporated in a single module.
[0016]
As a result, in particular, the number of connections is reduced, the overall length of the duct is shortened, and an advantage that modularity can be obtained is obtained.
[0017]
In the circuit of the present invention, as described above, at the outlet of the condenser, the cooling fluid is divided into two parts, the first part of which passes through the second decompression device and the second part of the cooling fluid is passed through. Cooling. The first part serves to subcool the second part, and the second part is directed towards the decompression device. This first part is sent back directly towards the compressor suction.
[0018]
According to another feature of the invention, a single module comprises only one inlet and two outlets.
[0019]
Advantageously, the single module inlet can be connected to a pipe protruding from the compressor, and the single module first outlet can be connected to a pipe drawn into the decompressor, The second outlet can be connected to a diverter pipe drawn into the inlet of the compressor.
[0020]
In the first embodiment of the present invention, the second pressure reducing device is directly installed between the second outlet of the condenser and the second branch of the internal heat exchanger.
[0021]
In that case, it is advantageous if the circuit further comprises a cylinder installed between the accumulator or the evaporator and the compressor installed between the single module and the decompressor.
[0022]
In the second embodiment of the present invention, the single module further includes an accumulator installed between the second decompression device and the second branch of the heat exchanger.
[0023]
The second pressure reducing device can be an external control type or a thermostat type.
[0024]
The circuit of the present invention can be used with a cooling fluid that exists as a gas phase and a liquid phase. At this time, the condenser condenses the cooling fluid.
[0025]
The circuit can also be used with a cooling fluid that exists only as a gas phase according to a supercritical pressure cycle, where the condenser constitutes a gas cooler for cooling the cooling fluid.
[0026]
In another aspect, the invention relates to a single module that can form part of an air conditioning circuit as defined above and comprises a condenser, an internal heat exchanger, and a second pressure reducing device.
[0027]
The details of the embodiments are described below by way of example only with reference to the accompanying drawings.
[0028]
The air-conditioning circuit shown in FIG. 1 mainly includes a compressor 10, a condenser 12, a decompression device 14, and an evaporator 16, and can flow cooling fluid in that order.
[0029]
This air conditioning circuit can be made in the form of a conventional circuit that operates with a cooling fluid that exists in two phases: a gas phase and a liquid phase. In that case, the cooling fluid in the gas phase is compressed by the compressor 10 and converted into a liquid phase in the condenser 12 (the flow of air passes through the condenser), and then decompressed to a low pressure by the decompressor 14, Finally, the vapor phase is changed in the evaporator 16. An air flow F passes through the evaporator. In this way, this air flow is cooled and sent into the automobile living space by the action of the extrusion pump 18.
[0030]
The circuit can also operate with a natural cooling fluid, such as carbon dioxide, according to a supercritical pressure cycle. In this case, the cooling fluid is always present as a gas phase. In a similar case, the condenser 12 constitutes a “gas cooler” that serves to cool the cooling fluid.
[0031]
According to the invention, the condenser 12 forms part of a single module 20 with an inlet 22 that can be connected to a pipe 24 protruding from the compressor 10.
[0032]
The condenser 12 passes through the first outlet 26 connected to the first branch 28 of the heat exchanger 30, which is called “internal heat exchanger”, and the second decompression device 34, and the second outlet of the heat exchanger 30. And a second outlet 32 connected to the branch portion 36.
[0033]
The heat exchanger 20 is referred to herein as an “internal heat exchanger” because it can exchange heat between two portions of the same fluid, ie, a cooling fluid.
[0034]
The condenser 10 and the heat exchanger 30 and the second pressure reducing device 34 are part of the single module 20. This single module is further connected to a first outlet 38 that can be connected to a pipe 40 that is drawn into the decompressor 14 and a second outlet 42 that can be connected to a diverter pipe 44 that is drawn into the inlet of the compressor 10. And.
[0035]
The pipe 40 reaches the accumulator 46, which is connected to the decompression device 14 by a pipe 48. This decompressor is connected to the evaporator 16 by a pipe 50. The evaporator 16 is connected to the cylinder 52 by a pipe 54. The cylinder 52 is connected to the inlet of the compressor by a pipe 56. The diversion pipe 44 leads into the pipe 56 upstream of the compressor 10.
[0036]
As a result, the first portion of the cooling fluid that protrudes from the condenser 12 passes through the decompressor 34 to cool the second portion of the cooling fluid. In this way, the first part of the cooling fluid can supercool the second part directed towards the decompression device 14. This first part is thus sent directly back to the compressor suction.
[0037]
In this way, module 20 is ready to be incorporated into a circuit and constitutes an assembly with only one inlet and two outlets. Furthermore, this can improve the supercooling of the part of the cooling fluid which is guided towards the decompression device 14 and then sent back to the compressor suction via the evaporator 16 and the cylinder 52.
[0038]
Note that in the circuit of FIG. 1, either accumulator 46 or cylinder 52 can be omitted.
[0039]
In a preferred embodiment, the pressure reducing device 34 is an externally controlled pressure reducing device or a thermostat type pressure reducing device that opens a passage toward the branch portion 36 of the heat exchanger 30 in accordance with the heat load of the circuit loop. Can do.
[0040]
Supercooling is necessary only when the heat load is large.
[0041]
The arrangement of the modules in the capacitor zone is a combination of the external temperature and the heat load of the circuit, and a very easy thermostat adjustment is possible.
[0042]
It is clear that the adjustment according to the delivery temperature or the condensation temperature itself is sufficiently performed.
[0043]
Note that by using an externally controlled decompression device, the operation is more accurate and is used with a more optimized circuit.
[0044]
The connection between the heat exchanger 30 and the suction of the compressor 10 can be provided with load loss elements to balance the pressure in the two lines (pipes 44 and 56) concentrated towards the compressor. .
[0045]
FIG. 2 shows a more sophisticated embodiment of the air conditioning circuit of the present invention. The circuit in FIG. 2 mainly includes the same components as those in FIG. 1, and the same reference numerals are given to the common components.
[0046]
The main difference is that the module 20 has an accumulator 58 installed between the second pressure reducing device 34 and the second branch 36 of the internal heat exchanger 30.
[0047]
Further, the accumulator 46 and cylinder 52 of the circuit of FIG. 1 are omitted.
[0048]
This embodiment is particularly suitable for natural cooling fluids, especially carbon dioxide, which operate in response to supercritical pressure.
[0049]
Since the high-pressure line (pipe 24 between the compressor 10 and the condenser 12) is in a gaseous state, the storage of cooling fluid is required to be performed in the low-pressure line.
[0050]
In this way, a second low pressure line is utilized in parallel with the main line for mounting the accumulator.
[0051]
The arrangement of the accumulator 58 located upstream of the heat exchanger 30 superheats the gas flowing toward the compressor, thus preventing the risk of compressor failure.
[0052]
Furthermore, a cylinder similar to the cylinder 52 of FIG. 1 can be arranged to allow it to be incorporated into the module 20.
[0053]
In the case of the circuit of FIG. 2, the decompressor 34 can be an externally controlled decompressor or an internally controlled decompressor.
[0054]
When the circuit operates with a natural cooling fluid, especially carbon dioxide, the control of the loop takes place in response to the high pressure. This high pressure is preferably monitored at a sufficient level so that heat can be accurately exchanged with the external environment. This presupposes the use of an externally controlled decompression device.
[0055]
When a thermostat decompression device is used, the high pressure is adjusted upstream of the evaporator, so that an internal inspection type decompression device can be used at the inlet of the evaporator.
[0056]
The single module 20 incorporating the condenser 12, the heat exchanger 30, the decompressor 34, and possibly the accumulator 58 can be made by means well known per se in heat exchanger technology.
[0057]
FIG. 3 shows an embodiment of a single module 20 that can form part of the air conditioning circuit of FIG. Elements common to the circuit of FIG. 1 are given the same reference numerals.
[0058]
The single module 20 comprises a condenser 12 formed by a number of tubes 58 arranged alternately with corrugated inserts 60 forming heat exchange fins. The tube 58 leads into the collection box 62 on one side and into the collection box 64 on the other side.
[0059]
The collection box 62 extends generally along the vertical direction, and the inside defines four continuous sections 66, 68, 70, 72 from high to low. The inlet 22 of the capacitor 12 communicates with the compartment 68.
[0060]
The collection box 64 extends generally along the vertical direction, and the inside defines four consecutive compartments 74, 76, 78, 80 from high to low. The compartments 74 and 80 are preferably in communication with each other by a vertical duct 82 incorporated into the collection box.
[0061]
The cooling fluid flows several times through the tube 58 by continuously passing through the compartments 68, 76, 70, 78, 72, 80 as indicated by the arrows. The cooling fluid then reaches compartment 74 by passing through duct 82 and further reaches compartment 66.
[0062]
An internal heat exchanger 30 formed by a first branch portion 28 made of a bundle of short tubes and a second branch portion 36 made of a bundle of long tubes is attached above the condenser 12. The long tube is plugged with the short tube.
[0063]
The two branches 28 and 36 are arranged between two collection spaces 84 and 86 located above the collection boxes 62 and 64, respectively.
[0064]
The collection space 84 has a side wall 88 through which the short pipe of the first branch section 28 communicates and an inner partition 90 through which the long pipe of the second branch section 36 communicates. The collection space 84 defines therein a compartment 92 that communicates the first branch 28 and the compartment 66 and a compartment 94 that communicates the outlet 42 and the second branch 36.
[0065]
The collection space 86 has a side wall 96 through which the short pipe of the first branch section 28 communicates and a partition 98 through which the long pipe of the second branch section 36 communicates. In this way, the collection space 86 defines two compartments. A section 100 communicating with the first branch and outlet 38 and a section 102 connecting the outlet 32 of the duct 82 and the second branch 36. Therefore, the collection space 86 includes an inlet duct 104 that communicates with the outlet 32 provided in the duct 82 at a lower portion thereof. The duct 104 accommodates a decompression device 34.
[0066]
The outlets 38 and 42 of the single module 20 are provided in the collection space 86 and the collection space 84, respectively.
[0067]
In this way, at the outlet of the condenser, some of the cooling fluid flows in the first branch 28 and further leaves the module from the outlet 38 of the collection space 86. The other part of the cooling fluid leaves the condenser from the outlet 32, passes through the decompressor 34, reaches the second branch 36, and exits from the outlet 42 of the collection space 84.
[0068]
The single module 20 shown in FIG. 4 is a variation of FIG. 3 and can form part of the circuit of FIG. Elements common to FIG. 2 are given the same reference numerals.
[0069]
The main difference compared to the module of FIG. 3 is that the outlet 32 of the duct 82 communicates with an accumulator 58 having a generally vertically extending tank shape.
[0070]
A decompressor 34 is accommodated in the outlet 32. The accumulator 58 houses a U-shaped duct 106. The duct has an inlet 108 located at the top and an outlet 110 installed at the top that communicates with the inlet duct 104 of the collection space.
[0071]
In this way, the second branch portion 36 of the internal heat exchanger 30 is supplied via the accumulator 58.
[0072]
Many variations of the circuit and single module of the present invention are possible.
[0073]
The field of application of the present invention is not limited to air conditioning for automobile vehicles.
[Brief description of the drawings]
FIG. 1 is a diagram showing an air conditioning circuit for an automobile vehicle according to a first embodiment of the present invention.
FIG. 2 is a diagram showing an air conditioning circuit for an automobile vehicle according to a second embodiment of the present invention.
3 is a cross-sectional view of a module that can form part of the air conditioning circuit of FIG. 1. FIG.
4 is a cross-sectional view of a module that can form part of the air conditioning circuit of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 12 Compressor 14 Pressure reduction device 16 Evaporator 18 Extrusion pump 20 Single module 22 Inlet 24 Pipe 26 Outlet 28 Branch part 30 Internal heat exchanger 32 Outlet 34 Decompression unit 36 Branch part 38 Outlet 40 Pipe 42 Outlet 44 Diverging pipe 46 Accumulator 48, 50 Pipe 52 Cylinder 54, 56 Pipe 58 Accumulator 60 Corrugated insert 62, 64 Collection box 66, 68, 70, 72 Compartment 74, 76, 78, 80 Compartment 82 Vertical duct 84, 86 Collection space 88 Side wall 90 Inside Partition 92, 94 Section 96 Side wall 98 Partition 100, 102 Section 104 Inlet duct 106 U-shaped duct 108 Inlet 110 Outlet F Air flow

Claims (11)

An air conditioning circuit comprising a compressor (10), a condenser (12), a pressure reducing device (14), and an evaporator (16), and capable of circulating a cooling fluid ,
A condenser (12) is connected to the first outlet (26) connected to the first branch (28) of the internal heat exchanger (30) and through the second decompressor (34). A second outlet (32) connected to the second branch (36),
The first branch (28) of the internal heat exchanger is connected to the circuit decompressor (14), and the second branch (36) of the internal heat exchanger is connected upstream of the compressor (10). ,
Capacitor (12) and the internal heat exchanger (30) and the second pressure reducing device (34) is characterized in that it is arranged in the form of units of the module (20) which can be placed in the circuit Air conditioning circuit.   2. Air conditioning circuit according to claim 1, characterized in that the single module (20) has one inlet (22) and two outlets (38) (42).   The single module inlet (22) can be connected to a pipe (24) protruding from the compressor (10), and the single module first outlet (38) is connected to a pipe (40 Characterized in that the single module second outlet (42) can be connected to a diverter pipe (44) drawn into the compressor inlet (10). The air conditioning circuit according to claim 2.   The second pressure reducing device (34) is installed directly between the second outlet (32) of the condenser (12) and the second branch (36) of the internal heat exchanger (30). The air conditioning circuit according to any one of claims 1 to 3, wherein the air conditioning circuit is characterized.   Having an accumulator (46) installed between a single module (20) and a decompressor (14) or a cylinder (58) installed between the evaporator (16) and the compressor (10). The air conditioning circuit according to claim 4, wherein the air conditioning circuit is characterized.   The single module (20) has an accumulator (58) installed between the second decompressor (34) and the second decompressor (34) of the internal heat exchanger (30). The air conditioning circuit according to any one of claims 1 to 3, wherein   The air conditioning circuit according to any one of claims 1 to 6, characterized in that the second decompression device (34) is of an external control type.   The air conditioning circuit according to any one of claims 1 to 6, characterized in that the second decompression device (34) is of a thermostat type.   Air conditioning circuit according to any one of claims 1 to 8, characterized in that the cooling fluid exists as a gas phase and a liquid phase and the condenser (12) condenses the cooling fluid.   The cooling fluid is present only as a gas phase to operate according to a supercritical pressure cycle, and the condenser (12) constitutes a gas cooler for cooling the cooling fluid, Item 9. The air conditioning circuit according to any one of Items 1 to 8. A single module comprising a condenser (12), an internal heat exchanger (30) and a second decompression device (34) which are part of an air conditioning circuit according to any of claims 1-10.

Images