CN113272557A

CN113272557A - Method, apparatus and air conditioner for operating rolling type compressor

Info

Publication number: CN113272557A
Application number: CN201980089371.2A
Authority: CN
Inventors: R·弗鲁思
Original assignee: Vitesco Technologies GmbH
Current assignee: Vitesco Technologies GmbH
Priority date: 2019-01-16
Filing date: 2019-12-05
Publication date: 2021-08-17
Anticipated expiration: 2039-12-05
Also published as: WO2020147886A1; CN113272557B; DE102019200480A1

Abstract

The invention relates to a method for operating a scroll compressor (110) for an air conditioner (100), wherein the scroll compressor (110) has a fixed spiral (101) and a spiral (102) movable relative to the fixed spiral (101), the movable spiral (102) being arranged in a housing space (104), comprising the following steps: reducing the pressure in the housing space (104) on a side (105) of the movable spiral (102) facing away from the fixed spiral (101); determining a trend (301) of current consumption of a drive motor (106) of the movable screw (102) during the lowering; determining a point in time (306) of the reduction in current consumption; -determining a value (309) of the pressure at the point in time (306), wherein the determined value (309) represents a disengagement of the movable spiral (102) from the fixed spiral (101); a reference pressure (305) is determined for a housing space (104) on a side (105) of the movable spiral (102) facing away from the fixed spiral (101), wherein the reference pressure (305) has a predetermined deviation (304) greater than the determined value (309) of the pressure.

Description

Method, apparatus and air conditioner for operating rolling type compressor

Technical Field

A method for operating a roller compressor for an air conditioner, in particular for a motor vehicle, is proposed. Furthermore, a device for carrying out such a method is proposed. Furthermore, an air conditioner with a rolling compressor, in particular for a motor vehicle, is proposed.

Background

The motor vehicle can be equipped with an air conditioner. Air conditioners have a compressor, also known as a supercharger. The compressor is used to compress an air conditioning agent for a refrigerator.

It is desirable that: a method for operating a roller compressor is proposed, which enables reliable operation. It is furthermore desirable that: an apparatus is proposed which enables reliable operation of a rolling compressor. It is furthermore desirable that: an air conditioner is provided which can be operated reliably.

Disclosure of Invention

According to at least one embodiment, a method for operating a scroll compressor for an air conditioner and a device designed to carry out the method are provided.

According to one embodiment, the scroll compressor has a fixed spiral part and a spiral part that is movable relative to the fixed spiral part. The movable spiral is arranged in the housing space.

Reducing the pressure in the housing space on the side of the movable spiral facing away from the fixed spiral. During the reduction period, the trend of the current consumption of the drive motor of the movable screw is determined. The time point of the reduction of the current consumption is determined. And calculating the value of the pressure at the time point. The determined value of the pressure represents the disengagement of the movable spiral from the fixed spiral. A reference pressure is determined for a housing space on a side of the movable spiral facing away from the fixed spiral. The reference pressure is greater than the determined value of the pressure by a predetermined deviation.

During operation of the rolling compressor, which can also be referred to as a screw compressor or a rolling supercharger, the movable screw is pressed axially against the fixed screw in order to seal the two screws against one another. The pressure must be so high that the movable spiral does not disengage undesirably during normal operation. The disengagement causes leakage and thus inefficient operation. The pressure should also not be too high, since this leads to increased friction and increased wear.

By intentionally reducing the pressure on the side of the movable spiral facing away from the fixed spiral, the compression pressure of the movable spiral towards the fixed spiral is reduced. The movable helix disengages from the fixed helix once the pressure is below a certain threshold below. The pressure on the side of the movable spiral facing away from the fixed spiral is no longer great enough to press the movable spiral towards the fixed spiral. Leakage occurs due to the detachment. The transport mass flow of the scroll compressor decreases. The pressure on the outlet side of the scroll compressor decreases. The drive torque of the electric drive motor decreases.

The drive motor is configured to rotate the movable screw. The drive motor rotates a shaft, for example. The rotation of the shaft is transmitted to the movable spiral, for example by means of kinematics, in order to spiral the movable spiral. The reduced drive torque is also shown in the current consumption of the drive motor. As soon as the movable spiral disengages from the fixed spiral, the current consumption of the drive motor is reduced due to the occurring leakage. The time at which the movable spiral disengages can therefore be determined easily and reliably from the determined course of the current consumption. The state of the scroll compressor at the time of disengagement can be obtained.

It is therefore also possible to determine the pressure which is just no longer sufficient to sufficiently press the movable spiral against the fixed spiral. Accordingly, the reference pressure is selected to be slightly higher than the pressure at the point in time of disengagement. The predefined deviation is sufficient to press the movable spiral towards the fixed spiral sufficiently to seal the two spirals against each other and to avoid undesired detachment. The deviation is chosen so small that relatively little friction and relatively little wear occurs. The deviation depends on the refrigerant used and therefore on the absolute process pressure present and on the design of the compressor. For example, the deviation is in the range including 1 to 2 bar.

In at least one embodiment, the scroll compressor has a pressure valve. The pressure valve is coupled on the outlet side to the housing space in order to control the pressure in the housing space on the side of the movable spiral facing away from the fixed spiral. By means of which the pressure can be lowered and raised. For example, the pressure in the housing space is reduced by means of the pressure valve in order to detect the point in time of the disengagement of the movable spiral. In operation of the roller compressor, a reference pressure in the housing space can be set by means of the pressure valve.

In at least one embodiment, the characteristic map for the pressure is adapted as a function of the reference pressure. By means of the characteristic map, the pressure in the housing space is predefined during normal operation of the roller compressor. Depending on the ascertained reference pressure, the characteristic map can be adapted and the changing events can be updated. The method described is therefore not carried out continuously, for example, during ongoing operation of the roller compressor, but rather, for example, at certain predefined points in time, time intervals or operating points. As a result, the characteristic map is updated and adapted, and accordingly, can be operated efficiently and reliably in accordance with the characteristic map.

In at least one embodiment, the determination of the point in time of the reduction in the current consumption comprises: the change in the gradient of the trend of the current consumption is determined. In particular, the slope is negative when the pressure in the housing space is reduced such that the movable spiral disengages. The slope after the disengagement is steeper than the slope when the movable screw is sufficiently pressed towards the fixed screw.

In at least one embodiment, the determination of the point in time of the reduction in the current consumption comprises: alternatively or additionally, a drop in the current consumption below a predetermined limit value for the current consumption is determined. For example, it is known that: the current consumption is at least large in normal operational operation without disengagement. If the current consumption falls below this minimum value, it is assumed that the movable spiral is disengaged.

In at least one embodiment, the determination of the point in time of the reduction in the current consumption comprises: alternatively or additionally, a relative decrease in the current consumption below a predetermined limit value for the decrease is determined. If the current consumption deviates from the previously measured value of the current consumption at this point in time, for example, by a certain predefined percentage, it is assumed that the movable spiral is disengaged. For example, if the deviation is greater than one percent or greater than one-half percent downwards, the movable spiral is assumed to be disengaged.

In at least one embodiment, the method steps are carried out as a function of a predefined operating state of the scroll compressor. The operating state may include, for example, the duration of operation, start-up, current consumption, outlet pressure or other parameters representative of the operation of the scroll compressor.

According to at least one embodiment, the air conditioner is designed as an air conditioner for a motor vehicle. The steps of the method are repeatedly carried out as a function of predefined operating states of the motor vehicle. The operating state of the motor vehicle comprises, for example, motor start, outside temperature, operating duration or other parameters which are representative of the operation of the motor vehicle.

According to at least one embodiment, an air conditioner has a scroll compressor as described herein according to at least one embodiment. The air conditioner has the apparatus described herein according to at least one embodiment. The device is coupled in signal technology with the scroll compressor for controlling the operation of the scroll compressor. In particular, the device is coupled to the pressure valve in terms of signal technology for controlling the pressure valve for setting the pressure in the housing space. The air conditioner is especially for motor vehicles.

Drawings

Further advantages, features and improvements result from the following embodiments, which are explained in conjunction with the figures.

Wherein:

FIG. 1 shows a schematic diagram of components of an air conditioner according to an embodiment; and is

Fig. 2 shows a schematic diagram of a signal trend according to an embodiment.

Detailed Description

Fig. 1 shows a schematic diagram of components of an air conditioner 100 according to an embodiment. The air conditioner 100 is in particular an air conditioner for a motor vehicle or is designed for use in a motor vehicle.

The air conditioner 100 includes a scroll compressor 110. The scroll compressor 110 is partially schematically shown in fig. 1.

The air conditioner 100 has an apparatus 200. The device 200 is, for example, an Electronic Control Unit (ECU). The device 200 is, for example, a control unit of a motor vehicle, which is designed to control or regulate the air conditioner 100. To this end, the device 200 has, for example, one or more processors, memories, and/or other electronic components.

The scroll compressor 110 has a drive motor 106. The drive motor 106 is an electric motor. The drive motor 106 is coupled to the movable screw 102 of the scroll compressor 110. The movable spiral 102 is also referred to as a spiral or a spiral roller. The drive motor 106 is designed to eccentrically rotate the movable spiral 102. The movable screw 102 is pressed towards the fixed screw 101. In operation, the movable spiral 102 rotates relative to the fixed spiral 101. The fixed screw 101 and the movable screw 102 are pressed against each other in the axial direction.

Due to the movement of the movable spiral 102 relative to the fixed spiral 101, the refrigerant is compressed during operation. The rolling compressor 110 thus functions as a supercharger of the air conditioner 100.

The movable screw 102 is arranged in a housing 103 of the rolling compressor 110. The housing 103 encloses a housing space 104 in which the movable spiral 102 is arranged.

The scroll compressor 110 has a pressure valve 107. The pressure valve 107 is in particular a so-called pressure regulating valve. The pressure valve 107 is connected to the device 200, for example, in terms of signaling. The pressure valve 107 is provided for setting the pressure in the housing space 104 on the side 105 of the movable spiral 102 facing away from the fixed spiral 101.

The pressure valve 107 is connected, for example, on the inlet side to the housing space 104, in particular to the housing space 104 at the facing side 105. The outlet of the pressure valve 107 is connected, for example, to the suction area of the roller compressor 110. Thus, the pressure on the diverging side 105 can be set by opening and closing the pressure valve 107. The housing space 104 is connected to the high-pressure outlet 109, for example, by means of a throttle 111 or a plurality of throttles.

The pressure in the housing space 104 on the side 105 facing away is decisive for the distance 108 in the axial direction between the fixed spiral 101 and the movable spiral 102. The spacing must be as small as possible or zero in order to avoid undesired leakage. The pressure in the housing space 104 on the side 105 facing away is selected to be particularly so great that the movable screw 102 is pressed sufficiently firmly against the fixed screw 101 in order to prevent the movable screw 102 from being able to escape axially away from the fixed screw 101 during normal operation. The pressure on the side 105 facing away is thereby not set too high in order to achieve as little friction and as little wear as possible.

As is apparent from fig. 2, a matching method is carried out for setting the pressure 104. The pressure in the housing space 104 can thus be determined, which not only achieves a sufficient compression but also is low enough to avoid increased friction and increased wear.

Time is plotted at the X-axis of fig. 2. The pressure and current consumption of the drive motor 106 are plotted at the Y-axis.

The trend 301 of the current consumption of the drive motor 106 is detected. The pressure in the housing space 104 on the facing side 105 is determined and a trend 302 of the pressure is detected. The pressure was intentionally reduced. As a result, the pressing pressure, which presses the movable screw 102 in the axial direction toward the fixed screw 101, drops. At time 306, the pressure in the housing space 104 is no longer sufficient. The distance 108 increases and in particular is so large that an adequate seal is no longer achieved.

Due to the pressure existing between the fixed spiral 101 and the movable spiral 102, the movable spiral 102 is axially displaced from the fixed spiral 101. Thereby, a leakage occurs between the two

spiral parts

101, 102. This can also be seen from the trend 303 of the high pressure at the outlet 107, which drops significantly at the time 306.

Due to the leakage, the drive torque of the roller compressor 110 and in particular of the drive motor 106 drops significantly. This drop is also shown in the trend 301 of the current consumption. The current consumption also drops significantly. In particular, the slope 308 after the time point 306 is significantly steeper than the slope 307 before the time point 306. The time 306 can thus be ascertained from the observation of the trend of the current consumption, at which the pressure in the housing space 104 is reduced in such a way that the movable spiral 102 is pushed away from the fixed spiral 101. Thus, the value 309 of the pressure at time 306 is known, which is just no longer sufficient to cause the fixed spiral 101 and the movable spiral 102 to press axially sufficiently strongly against one another to avoid detachment.

Based on the value 309 of the pressure, a reference pressure 305 can be determined, which exceeds the value 309 of the pressure just. The reference pressure 305 has a small deviation 304 from the value 309 of the pressure. The reference pressure 305 is slightly higher than the value 309 of the pressure. The reference pressure 105 in the housing space 104 on the facing side 105 is therefore the minimum pressure necessary to press the movable screw 102 sufficiently strongly against the fixed screw 101 to avoid detachment and excessive leakage. In this case, as little friction and as little wear as possible are achieved, since the reference pressure 304 can be selected to be very small and, in particular, as small a tolerance as possible must be taken into account. The deviation 304 is predefined, for example, as a function of the operating point or the ascertained value 309 relative to the pressure. The reference pressure 305 is predefined, for example, absolutely or relatively, and is, for example, 1 to 2bar, or more than 2bar or less than 1 bar.

As an alternative or in addition to the evaluation of the

gradients

307, 308, for example, the following is determined as a function of the predefined limit value 310 for the current consumption: the movable spiral part 102 is disengaged from the fixed spiral part 101 due to the pressure drop in the housing space 104. When the current consumption profile 301 is below the limit value 310, the movable spiral 102 is then supposed to be disengaged from the fixed spiral 101. The time point 306 can therefore be determined at which the trend 301 of the current consumption intersects the limit value 310.

The ascertained reference pressure 305 can be used to update and adapt a characteristic map for the operation of the roller compressor 110. For example, material changes, wear, or other influences can change the characteristics of the scroll compressor 110 over the life of the scroll compressor 110. However, with the method described, the value 309 of the pressure and the reference pressure 305 dependent thereon can be determined precisely and the contact pressure of the movable screw 102 against the fixed screw 101 can be updated accordingly.

The method enables the setting of the contact pressure by means of the pressure valve 107 without a throttle bore in the movable spiral 102. A complete control circuit is also not necessary for setting the pressure in the housing space 104. However, the control characteristic map can be adapted as optimally as possible in the operating point. The control characteristic map depends, for example, on the high pressure or suction pressure at the outlet 109. The pressure in the housing space 104 that presses the movable spiral 102 against the fixed spiral 101 is also referred to as back pressure in english. The pressure is intentionally reduced until the two

spiral parts

101, 102 disengage from each other. Due to the high internal leakage that occurs, the drive torque of the compressor drops significantly. The drive torque can be proportionally determined from the current consumption. Therefore, the detached state can be detected by the trend 301 of the current consumption. On the basis of this, an improved characteristic map can be determined, which lies just above the deviation limit. The method is accordingly repeated at time intervals in order to determine the change in the departure point in the characteristic diagram during operation. The characteristic map can therefore be updated and adapted at certain intervals. The method is carried out, for example, at intervals of a predetermined time period. The method is for example carried out at the start of a motor vehicle or at the start of the air conditioner 100, respectively. Additional time periods and repetition intervals are also possible.

The method enables the setting of the compression pressure in the housing space 104 such that the compression pressure is just large enough for the fixed spiral 101 and the movable spiral 102 to seal sufficiently axially against each other. In this case, the pressure is as low as possible and as little friction and as little wear as possible are thereby achieved. Tolerances and variations of the components can thereby also be compensated. In particular, inherent components like, for example, the

spirals

101, 102 can be used which are subject to relatively large tolerances. This tolerance can then be compensated by means of the method described. The component can thus be manufactured, for example, inexpensively. The contact pressure in the housing space 104 can be determined and adapted during operation of the air conditioner 100. By means of the method it is also possible to compensate and to take into account the variations between the individual rolling compressors 110 of the series.

Therefore, the rolling compressor 110 can be reliably operated by means of the apparatus 200.

Claims

1. A method for operating a rolling compressor (110) for an air conditioner (100), wherein the rolling compressor (110) has a fixed spiral (101) and a spiral (102) movable with respect to the fixed spiral (101), the movable spiral (102) being arranged in a housing space (104), the method comprising the steps of:

-reducing the pressure in the housing space (104) on the side (105) of the movable spiral (102) facing away from the fixed spiral (101);

-determining a trend (301) of the current consumption of the drive motor (106) of the movable screw (102) during the lowering;

-finding a point in time (306) of the reduction of the current consumption;

-determining a value (309) of the pressure at the point in time (306), wherein the determined value (309) represents a disengagement of the movable spiral (102) from the fixed spiral (101);

-ascertaining a reference pressure (305) for a housing space (104) on a side (105) of the movable spiral (102) facing away from the fixed spiral (101), wherein the reference pressure (305) is greater in magnitude than the ascertained value (309) of the pressure by a predefined deviation (304).

2. Method according to claim 1, wherein the scroll compressor (110) has a pressure valve (107), which pressure valve (107) is coupled with the housing space (104) on the outlet side in order to control the pressure in the housing space (104) on the side (105) of the movable spiral (102) facing away from the fixed spiral (101), the method comprising:

-reducing said pressure by means of said pressure valve (107).

3. The method according to claim 1 or 2, comprising:

-matching a family of characteristic curves for said pressure as a function of said reference pressure (305).

4. The method according to any of claims 1 to 3, wherein the evaluation of the point in time (306) of the reduction of the current consumption comprises:

-determining a change in slope (307, 308) of the trend (301) of the current consumption.

5. The method according to any of claims 1 to 4, wherein the evaluation of the point in time (306) of the reduction of the current consumption comprises:

-determining a drop in the current consumption below a predetermined limit value (310) for the current consumption.

6. The method according to any of claims 1 to 5, wherein the evaluation of the point in time (306) of the reduction of the current consumption comprises:

determining a relative decrease in the current consumption below a predetermined limit value for the decrease.

7. The method of any of claims 1 to 6, comprising:

-repeatedly performing steps according to at least one predefined operating condition of said rolling compressor (110).

8. The method according to any one of claims 1 to 7, wherein the air conditioner (100) is configured for a motor vehicle, the method comprising:

-repeatedly carrying out the steps according to at least one predefined operating state of the motor vehicle.

9. An apparatus configured to perform the method of any one of claims 1 to 7.

10. An air conditioner is provided with:

-the device (200) according to claim 9;

-a rolling compressor (110), wherein the device (200) is coupled in signal technology with the rolling compressor (110) for controlling the operation of the rolling compressor (110).