Patent Application
20240200837
The invention relates to electrical refrigerant compressors for air-conditioning systems, in which a filter is arranged in a region in front of a spiral nozzle insert of the refrigerant compressor, as seen in a direction of the mass flow of a refrigerant of the refrigerant compressor, to prevent blockages in the refrigerant compressor.
The invention also relates to a method for operating a refrigerant compressor, in which particles exceeding a predefined size are filtered out in a region in front of a spiral nozzle insert of the refrigerant compressor, as seen in a direction of the mass flow of a refrigerant of the refrigerant compressor.
It is known from the prior art that so-called air-conditioning compressors or electrical refrigerant compressors, which are driven by means of an electric motor, are used for air-conditioning vehicles. This applies in particular also to electrically driven or at least partially electrically driven vehicles, such as electric cars or vehicles with a hybrid drive.
In particular, the description relates to electrical refrigerant compressors for air-conditioning systems in vehicles in which filters are used to prevent blockages. Such a filter is used in particular in a region in front of a spiral nozzle insert or a spiral nozzle of the refrigerant compressor, as seen in a direction of the mass flow of a refrigerant of the refrigerant compressor.
It is known from the prior art that a back pressure behind a revolving compressor spiral is necessary for proper operation of such an electrical refrigerant compressor. This back pressure is generated by a mass flow of the refrigerant, which mass flow is regulated by a control valve in combination with a spiral nozzle insert and a spiral nozzle. The spiral nozzle has a reduced cross-section or diameter, as a result of which there is a risk of particles in the refrigerant blocking the spiral nozzle insert or the spiral nozzle. Such a blockage reduces the efficiency of the refrigerant compressor and/or can lead to malfunctions.
DE 10 2019 101 855 A1 discloses a spiral compressor in particular for use in motor vehicle air-conditioning systems. Disclosed in particular is a spiral compressor with an oil recirculation unit, which has a stationary spiral and an orbiting spiral, wherein between the spirals gas is sucked in from a low-pressure space, compressed and conveyed into a high-pressure space. Furthermore, a back pressure space is formed, which is connected to the orbiting spiral and presses the orbiting spiral onto the stationary spiral as back pressure for compression, in order to allow movement of the orbiting spiral in the stationary spiral with the least friction possible by means of a balance of forces.
It is also disclosed that a low-pressure spiral nozzle is formed from a cylindrical cavity in the central housing, which cavity is preferably also designed as a cylinder bore. A spiral nozzle insert is in turn arranged in the cylindrical cavity. The spiral nozzle insert interacts with the wall of the cylindrical cavity such that the spiral nozzle is formed between the surface of the spiral nozzle insert and the wall of the cylindrical cavity. The surface of the spiral nozzle insert preferably has a spiral-shaped groove, which can also be referred to as a coil and forms a spiral-shaped throttle channel in the region where the spiral nozzle insert is in contact with the wall of the cylindrical cavity.
Spiral compressors having a spiral nozzle insert are thus known from the prior art. In such refrigerant compressors, it is also known to arrange a filter in a region of the mass flow in front of the spiral nozzle insert or in front of the spiral nozzle in order to filter particles which can possibly block the nozzle.
It is known to use filters which, according to the prior art, have a typical mesh size of 125 μm, for example, in compressor systems in order to filter out particles which could block the spiral nozzle insert or the spiral nozzle.
The use of such an additional filter requires a corresponding amount of additional installation space, at least one corresponding assembly step for arranging the filter, and thus additional costs in the production of an electrical refrigerant compressor.
There is thus a need for an improved refrigerant compressor for air-conditioning systems and an improved method for operating a refrigerant compressor.
The object of the invention consists in specifying refrigerant compressors for air-conditioning systems and a method for operating a refrigerant compressor with which safe functioning of a refrigerant compressor is achieved and in which the effort during production of the refrigerant compressor and the costs are reduced.
The object is achieved by subject matter having the features as shown and described herein.
The object is also achieved by a method having the features as shown and described herein.
It is provided for a gap or a gap filter with a defined geometric shape and defined dimensions to be formed in the housing of the refrigerant compressor or in the central housing of the refrigerant compressor in a region in front of a spiral nozzle insert or in front of a nozzle to be protected, as seen in the movement direction of the mass flow of the refrigerant.
To this end, it is provided for the gap or the gap filter to be formed between a housing part of the refrigerant compressor such as a central housing and a friction plate arranged on this housing part. Owing to the arrangement of the friction plate, the gap according to the invention is formed on the one hand and the housing of the refrigerant compressor is sealed on the other hand, so that no refrigerant can escape from the refrigerant compressor. The friction plate can also be exchanged, and in this way the refrigerant compressor can be repaired or adapted to changed operating conditions if required.
Owing to its specific contour and its defined dimensions, the gap or gap filter formed makes it possible for particle sizes which would normally block the spiral nozzle insert or the spiral nozzle to be filtered out. As a result, a separate filter according to the prior art in front of a spiral nozzle insert or a spiral nozzle in the mass flow of the refrigerant is no longer necessary. For the sake of simplicity, only the term gap is used below, which forms the gap filter.
It is provided for the gap to be defined in its dimensions such that particle sizes which would normally lead to the aforementioned blockages are filtered out and on the other hand that the gap is large enough to avoid influencing the mass flow of the refrigerant in its movement or to influence it only insignificantly. The gap formed increases the flow resistance of the flowing refrigerant only insignificantly, and therefore no changes to the dimensioning or the basic design of an existing refrigerant compressor are necessary. The design only has to be adapted in a region of the housing part of the refrigerant compressor in which the friction plate is arranged.
It is provided for the gap to be formed in a ring in a region at the inlet of a spiral nozzle insert by means of an annular molding of the central housing of the refrigerant compressor and the friction plate. The annular gap is arranged centered around a central axis of a bore for a spiral nozzle, wherein the annular gap has an inner diameter which is equal to the diameter of the bore for the spiral nozzle or greater than the diameter of the bore for the spiral nozzle.
Furthermore, it is provided for the housing part or central housing in which the bore for the spiral nozzle is arranged to have an annular molding surrounding the bore, said molding having a trapezoidal or rectangular cross-section. A region of this annular molding which is a circular ring-shaped flat face forms the gap with its filter effect by means of the friction plate arranged parallel to this circular ring-shaped flat face. The friction plate is likewise flat at least in a region of its surface opposite and parallel to the circular ring-shaped flat face. The friction plate can also be completely flat.
In particular, it is provided for the gap forming between the circular ring-shaped flat face of the molding and the friction plate to have a size within the range between 0.1 mm and 0.2 mm, in particular within a range between 0.04 and 0.16 mm.
Furthermore, it is provided for the inner diameter of the circular ring-shaped flat face of the molding to be within a range between 6 mm and 12 mm. The difference between the inner diameter of the circular ring-shaped flat face of the molding and the outer diameter of the circular ring-shaped flat face of the molding, which is also referred to as the width of the circular ring-shaped flat face, is within a range between 1 mm and 3 mm.
Such dimensioning of the gap makes it possible on the one hand to filter out particle sizes which would normally block the spiral nozzle insert or the spiral nozzle and on the other hand to avoid disruptively reducing the mass flow of the refrigerant through the gap as a result of gap blockages.
A gap blockage means the accumulation of particles at the gap, which cannot pass through the gap owing to their dimensions. These accumulations correspond to the filtered particles retained by a filter designed according to the prior art.
In practical experiments, a dimensioning of the gap with the dimensions inner diameter of the circular ring-shaped flat face of 8 mm, outer diameter of the circular ring-shaped flat face of 11 mm, and gap size of 0.15 mm results in a significant influence on the mass flow of the refrigerant of the refrigerant compressor only at a gap blockage rate of greater than or equal to 90%. The mass flow of the refrigerant through the gap and the functional operation of the electrical refrigerant compressor is thus unaffected or only insignificantly affected with gap blockage up to approximately 90%.
The design according to the invention of the gap makes it possible by means of an annular channel for the flow to pass peripherally around the molding forming the gap and thus provides sufficient filter space or filter area so that only partial clogging of the gap (gap blockage) does not affect the mass flow of the refrigerant.
It is provided for there to be produced in the annular channel a peripheral mass flow of the inflowing refrigerant which is as uniform as possible and thus a uniform flow around the annular channel and the molding on all sides. To this end, the inflowing refrigerant is introduced via an inflow first into a side chamber partially flow-connected to the annular channel. From this side chamber, the refrigerant then flows via a transition region into the annular channel. Such a transition region, which extends for example over a circular segment section of the annular channel within a range between 60 degrees and 100 degrees, allows an improved, uniform introduction of the refrigerant over a larger area into the annular channel, in comparison with a direct supply of the refrigerant into the annular channel via the inflow. Owing to the indirect introduction of the refrigerant into the annular channel via the side chamber and the correspondingly sized transition region, turbulence in the mass flow of the refrigerant, as occurs at small openings and/or at edges, is reduced.
In an embodiment according to the invention of the gap with its filter effect, a considerable reduction in the installation space is achieved. Moreover, an additional component such as a filter is not needed. This results in a simplification of the assembly of the electrical refrigerant compressor and in a cost saving in the production of an electrical refrigerant compressor.
Further details, features and advantages of embodiments of the invention can be found in the description of exemplary embodiments below with reference to the associated drawings. In the drawings:
In the central housing (2), between the annular channel (6) and the bore (3) for the spiral nozzle insert (4), a molding (8) is formed surrounding the bore (3), said molding having a trapezoidal or rectangular cross-section. This region of the molding (8) in the central housing (2) is shown in
The gap (11) or gap filter according to the invention is formed between a circular ring-shaped face (9) of the molding (8) and a friction plate (10) closing the refrigerant compressor (1). To this end, the trapezoidal or rectangular molding (8) in the central housing (2) is designed such that there is a spacing, which is within a range between 0.04 and 0.16 mm, between the circular ring-shaped face (9) of the molding (8) and the friction plate (10).
The refrigerant passing via the inflow (7) into the annular channel (6) moves through the gap (11) and passes into the bore (3) to the spiral nozzle insert (4). This mass flow (12) of the refrigerant is shown in
Owing to the provided dimensioning of the gap (11) formed according to the invention, particles exceeding a predefined size are filtered out in that these particles cannot pass via the gap (11) into the region of the spiral nozzle insert (4).
Such particles are thus prevented from blocking the region of the spiral nozzle insert (4) with its nozzle, as is achieved according to the prior art by the use of a separate small-meshed filter.
Also shown is the annular channel (6) which runs in a circle around the bore (3) and is connected at least indirectly to the inflow (7) for a refrigerant.
It is provided for there to be produced in the annular channel (6) a peripheral mass flow (12) of the inflowing refrigerant which is as uniform as possible and thus a uniform flow around the annular channel (6) and the molding (8) on all sides. To this end, the inflowing refrigerant is introduced via an inflow (7) first into a side chamber (14) partially flow-connected to the annular channel (6). From this side chamber (14), the refrigerant then flows via a transition region (15) into the annular channel (6). Such a transition region (15), which extends for example over a circular segment section of the annular channel (6) within a range between 60 degrees and 100 degrees, allows an improved, uniform introduction of the refrigerant over a larger area into the annular channel (6), in comparison with a direct supply of the refrigerant into the annular channel (6) via the inflow (7). The transition region (15) is indicated in
Owing to the indirect introduction of the refrigerant into the annular channel (6) via the side chamber (14) and the correspondingly sized transition region (15), turbulence in the mass flow (12) of the refrigerant, as occurs at small openings and/or at edges, is reduced.
In the view from above of
Multiple arrows show the mass flow (12) of the refrigerant from the inflow (7) via the annular channel (6) and many points of the annular gap (11) to the spiral nozzle insert (4) with its coils (5).
On the inlet side means that the gap (11) is formed in a region in which the mass flow (12) of the refrigerant reaches the inlet region of the spiral nozzle insert (4) from the annular channel (6) via the gap (11).
The refrigerant filtered via the gap (11) or gap filter flows through the coils (5) of the spiral nozzle insert (4) and passes to a nozzle-like end (13) shown at the lower end of the spiral nozzle insert (4) in
As is usual in the prior art, the spiral nozzle insert (4) can have a countersunk bore in the region of its central axis, as shown by way of example in
The mass flow (12) of the refrigerant of the refrigerant compressor (1) is also shown in
From this annular channel (6), the refrigerant flows via the likewise annular gap (11) to the spiral nozzle insert (4) with its coils (5). In the example, the gap (11) forming between the molding (8) and the friction plate (10) has a width of 0.15 mm. In
In the example of
In the graph of
In the graph of
The graph of
As has been found, an accumulation of particles exceeding a predefined size at the gap (11) has no or only an insignificant effect as long as this gap blockage Rs remains below a rate or a value of 90%.
The volumetric flow qm of the refrigerant, which is approximately 1.91 kg/h in the example of
Only upwards of a gap blockage Rs of more than 90% does a decrease in the volumetric flow qm of the refrigerant occur, which can have a negative effect on the operation of the electrical refrigerant compressor (1). In the case of a gap blockage Rs of approximately 95%, the volumetric flow qm of the refrigerant is thus reduced to a value of approximately 1.85 kg/h, which corresponds to a reduction in the volumetric flow qm of the refrigerant of approximately 3%. In the case of a gap blockage Rs of approximately 98%, the volumetric flow qm of the refrigerant is reduced to a value of approximately 1.6 kg/h, which corresponds to a reduction in the volumetric flow qm of the refrigerant of approximately 16%.
The diagram shows that the safe operation or functional safety of the gap filter according to the invention formed by the gap (11) is ensured over a very wide range of a gap blockage Rs.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 130 131.9 | Nov 2021 | DE | national |
| 10 2022 118 029.8 | Jul 2022 | DE | national |
This is a U.S. national phase patent application of PCT/KR2022/016416 filed Oct. 26, 2022 which claims the benefit of and priority to German Patent Application No. 10 2022 118 029.8 filed Jul. 19, 2022 and German Patent Application No. 10 2021 130 131.9 filed on Nov. 18, 2021, the entire contents of each of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2022/016416 | 10/26/2022 | WO |
