US20160356535A1

US20160356535A1 - Ac refrigerant circuit

Info

Publication number: US20160356535A1
Application number: US14/731,808
Authority: US
Inventors: Gopala K. Garnepudi; Jeffrey A. Bozeman
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2015-06-05
Filing date: 2015-06-05
Publication date: 2016-12-08
Also published as: CN106247648A; DE102016209500A1

Abstract

A number of variations may include a refrigeration circuit which may include a compressor operably coupled to an evaporator. Additionally, a compressor may be operably coupled to the evaporator using the suction line. Moreover, the suction line may include a pressure sensor and a temperature sensor.

Description

TECHNICAL FIELD

The field to which the disclosure generally relates to includes refrigerant circuits and methods of making and using the same.

BACKGROUND

Refrigeration circuits may include various designs in order to measure or predict characteristics of the refrigeration circuit.

SUMMARY OF ILLUSTRATIVE VARIATIONS

A number of variations may include a refrigeration circuit which may have a condenser which may be operably coupled to an evaporator via a liquid line and expansion valve. Additionally, a compressor may be operably coupled to the evaporator using a suction line. Moreover, the suction line may include a pressure sensor and a temperature sensor.
A number of other variations may include a system which may include a condenser. The condenser may be operably coupled to an evaporator via a liquid line and expansion valve. Moreover, a compressor may be operably coupled to the evaporator via a suction line. Additionally, a pressure sensor and a temperature sensor may be disposed in the suction line.
Yet a number of other variations may include a method which may include first providing a refrigeration circuit. The refrigeration circuit may include a condenser operably coupled to an evaporator and may further include a compressor operably coupled to the evaporator. The compressor may be operably coupled to the evaporator via a suction line. Next, both a pressure and a temperature may be directly measured in the suction line.
Other illustrative variations within the scope of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing variations within the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Select examples of variations within the scope of the invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of a system according to a number of variations.

DETAILED DESCRIPTION OF ILLUSTRATIVE VARIATIONS

The following description of the variations is merely illustrative in nature and is in no way intended to limit the scope of the invention, its application, or uses.
Referring now to the variation illustrated in FIG. 1, a refrigeration circuit 10 which may include a condenser 12. The condenser 12 may be operably coupled to an evaporator 14. Additionally, a compressor 16 may be operably coupled to the evaporator 14 using a suction line 18. It is contemplated that the suction line 18 may include a pressure sensor 20 and a temperature sensor 22.
Referring again the variation illustrated in FIG. 1, a system 30 may be provided. The system 30 may be a refrigerant system, or any other system as known by one of ordinary skill in the art. Additionally, it is contemplated that the system 30 may be a closed circuit. It is also contemplated that the system 30 may be an AC refrigeration circuit or other circuit as known by one of ordinary skill in the art.
Referring again to the variation illustrated in FIG. 1, the refrigeration circuit 10 may include the evaporator 14. It is contemplated that the evaporator 14 may be any type of evaporator as known by one of ordinary skill in the art including but not limited to a forced circulation evaporator, a failing film evaporator or a rising film evaporator. It is additionally contemplated that the evaporator 14 may be constructed and arranged to turn a working fluid from a liquid form into its gaseous form. It is contemplated that the evaporator 14 may also include an inlet 32 and an outlet 34 for inlet and outlet of the working fluid. Moreover, a sensor 36 may be disposed on any portion of the evaporator 14 including the inlet 32, the outlet 34 or the main portion of the evaporator 14. The sensor may be a pressure sensor, a temperature sensor, a combination sensor or any other sensor as known by one of ordinary skill in the art.
Referring again to the variation illustrated in FIG. 1, it is contemplated that the compressor 16 may be any type of compressor as known by one of ordinary skill in the art including but not limited to a central fugal compressor, a diagonal or mixed flow compressor, an axial flow compressor, a rotary screw compressor, an air bubble compressor, hermetically sealed, open, or semi-hermetically sealed compressor. It is contemplated that the compressor 16 may include at least one inlet 38 and at least one outlet 40. Moreover, the compressor 16 may be operably coupled to the evaporator 14 using the suction line 18. The suction line 18 may be constructed and arranged to move the working fluid from the evaporator 14 to the inlet 38 of the compressor 16. It is contemplated that the working fluid may be a vapor when the working fluid is flowing through the suction line 18. It is additionally contemplated that the suction line 18 may include at least one direct measuring apparatus. The direct measuring apparatus may be a pressure sensor 20, a temperature sensor 22, a combination sensor, or any other sensor as known by one of ordinary skill in the art. It is contemplated that by directly measuring the temperature and pressure in the suction line 18, compressor failures along with a core freezing condition may be avoided.
Referring again to the variation illustrated in FIG. 1, the outlet 40 of the compressor 16 may be operably coupled to a discharge line 42. Additionally, the discharge line 42 may be operably coupled to the condenser 12. It is contemplated that the condenser 12 may be any type of condenser as known by one of ordinary skill in the art including a surface condenser, a condenser unit, or a direct contact condenser. The condenser 12 may be constructed and arranged to condense the working fluid from the discharge line 42 into a liquid form. When the working fluid is changed into a liquid, latent heat may be given up by the working fluid.
Referring again to the variation illustrated in FIG. 1, the discharge line 42 may include at least one direct measuring device 44. It is contemplated that the direct measuring device 44 may be a temperature sensor, a pressure sensor, or any other sensor as known by one of ordinary skill in the art. It is additionally contemplated that the discharge line 42 may not include a pressure sensor. In the variation where no pressure sensor is disposed in the discharge line 42, the pressure of the discharge line 42 may be estimated or determined based on an algorithm or other indirect sensing methods as known by one of ordinary skill in the art.
Referring again to the variation illustrated in FIG. 1, it is contemplated that the direct measuring device may be operably coupled to a controller. The direct measuring device may send information that is directly, or indirectly sensed to the controller. The controller may be constructed and arranged to use information from the direct measuring device to determine directly or indirectly whether a core freeze condition may occur. It is contemplated that a core freeze condition may occur when the compressor 16 control allows a low evaporator pressure and/or pumps liquid working fluid through the compressor 16 or at other conditions as known by one of ordinary skill in the art. By using the direct measuring device at the suction line 18, the controller may determine if the working fluid is at optimal conditions for the evaporator 14. If the controller determines the working fluid is not at optimal or near optimal conditions, the controller may stop or otherwise control the system to prevent the core freeze condition or other undesirable conditions.
Moreover, the condenser 12 may be operably coupled to the evaporator 14 using a liquid line 46. The liquid line 46 may be constructed and arranged to move the working fluid from the condenser 12 to the evaporator 14 using an expansion valve 53.
It is contemplated that the direct measuring device and the controller may be constructed and arranged to control the working fluid using various algorithms. The algorithms may include and are not limited to a combo sensor compressor torque algorithm, a combo sensor low charge algorithm, and a combo sensor evaporator capacity algorithm.
It is contemplated that the combo sensor compression torque algorithm may begin by inputting a compressor inlet temperature, working fluid temperature, RPM, an outlet temperature, or other input which may be directly or indirectly measured or sensed in the system. The sensed or measured features may then be input into Step 1 where Step 1 may compute a compressor inlet super heat by using the compressor pressure and the compressor temperature. The inlet superheat may then be moved into Step 2. Step 2 may also include an additional input of the compressors isentropic efficiency which may be calculated or sensed based on any of the other inputs including but not limited to compressor inlet temperature, compressor inlet pressure, RPMs, or compressor outlet temperature. Step 2 may compute the compressor outlet pressure. The compressor outlet pressure may be computed using isentropic efficiency, compressor RPM, compressor inlet superheat, and compressor outlet temperature. The compressor outlet temperature which may be computed in Step 2 may then be moved to Step 3. Step 3 may be constructed and arranged to compute a compressor ratio. In order to compute the compressor ratio, Step 3 may use the compressor inlet pressure and may additionally use the compressor outlet pressure. The compressor ratio may be transferred to Step 4. Additionally, Step 4 may include additional input of a compressor volumetric efficiency which may be directly or indirectly sensed or measured in the system. Additionally Step 4 may also compute the compressor flow. The compressor flow may be computed using compressor inlet pressure, compressor superheat, compression ratio, and compressor volumetric efficiency. The compressor flow may then be inputted into Step 5. Step 5 may be constructed and arranged to compute a compressor torque. The compressor torque may be computed by using the compressor ratio, compressor RPM, compressor flow, and compressor inlet pressure. The compressor torque may then be populated and may be evaluated.
It is contemplated that the controller may be additionally or alternatively constructed and arranged to include a combo sensor evaporator capacity control algorithm. The combo sensor evaporator capacity control algorithm may be constructed and arranged to provide data which may be useful in determining and controlling the working fluid and/or other components of the system. It is contemplated that in Step 1, inputs may include but are not limited to compressor inlet pressure, compressor inlet temperature, compressor outlet pressure and blower speed may be used. The inputs from Step 1 may be entered into Step 2. The inputs may then be used in Step 2 in order to compute suction pressure drop. The suction pressure drop may be computed using vehicle speed, compressor outlet pressure, compressor inlet pressure, and hose configuration calibration. Next, in Step 3, the rolling average evaporator outlet pressure may be computed. The rolling average evaporator outlet pressure may be computed using compressor outlet pressure suction line pressure drop and calibration C time frame. The computed rolling average evaporator outlet pressure computed in Step 3 may be inputted into Step 4. It is contemplated that Step 4 may compute a freeze target pressure. The freeze target pressure may be computed using the evaporator outlet pressure, the compressor outlet pressure, the compressor outlet temperature, suction line pressure drop, and blower speed. It is contemplated that Step 5 may be a logic step. Step 5 may determine whether the rolling average evaporator outlet pressure is above the freeze target pressure. If the rolling average evaporator outlet pressure is above the freeze target pressure then the compressor control may be reset and Steps 2-5 may be repeated. However, if the rolling average evaporator outlet pressure is not above the freeze target pressure, it is contemplated that the controller may be constructed and arranged to incrementally increase the compressor control pressure up by approximately 10 kPA. Once the compressor control pressure has been raised, Steps 2-5 may be repeated.
It is also contemplated that the controller may additionally or alternatively include a combo sensor low charge algorithm. The combo sensor low charge algorithm may include a first step which includes the inputs of compressor inlet pressure and temperature. Next in Step 2, the compressor inlet pressure and the compressor inlet temperature may be used to compute the compressor inlet superheat. The compressor inlet superheat may then be moved to Step 3. It is contemplated that Step 3 may include computing the rolling average of the compressor inlet superheat. It is contemplated that the rolling average compressor inlet superheat may be computed using a calibration time frame. Next, the rolling average compressor inlet superheat may be moved to Step 4, it is contemplated that Step 4 may be a decision step. It is contemplated that if the rolling average compressor inlet superheat is above a low charge superheat max which may be a constant known by one of ordinary skill in the art, then the loop may continue onto Step 5. However, if the rolling average compressor inlet superheat is not above the low charge superheat max then Steps 2-4 may be repeated. Once it is determined that the rolling average compressor inlet superheat is above the low charge superheat max, Step 5 may be another decision step. It is contemplated that Step 5 may compare the rolling average compressor inlet superheat to the EATA (Evaporator Air Temperature Average) max. In Step 5, if the rolling average compressor inlet superheat is above the EATA max, the clutch may be disabled for up to approximately 60 seconds. However if the rolling average compressor inlet superheat is not above the EATA max then the loop may continue onto Step 6. It is contemplated that Step 6 may be an additional decision or comparison step. In Step 6, it is contemplated that if the EATA is higher than the EATA maximum then the loop has reached its end. However, if the EATA is not higher than the EATA maximum, the EATA may be incremented upward by approximately 1 degree. Once the EATA is raised by approximately 1 degree, the loop may begin again at Step 2. It is contemplated that the EATA may be reset during calibration. Additionally it is contemplated that the EATA max at OAT (Outside Ambient Temperature) is OAT.
It is contemplated that the combo sensor compressor torque algorithm, the combo sensor evaporator capacity control algorithm, and the combo sensor low charge algorithm may be used simultaneously with one another, consecutively, or in any combination as desired by one of ordinary skill in the art. Additionally it is contemplated that each of the algorithms may be used singularly or in any combination with one another as desired by one of ordinary skill in the art.
It is contemplated that the variation illustrated in FIG. 1 may improve the efficiency of the refrigeration circuit 10. Moreover, evaporator core freeze detection may be immediately detected and remedied therefore the core freeze condition may be monitored more closely and directly. Additionally, the variation illustrated may eliminate the need for an evaporator air temperature (EAT) sensor and may also potentially eliminate a high side pressure sensor which may be disposed in prior art systems.
In operation, the working fluid may flow through the liquid line 46 to the expansion valve 53 to drop the pressure and temperature then may flow into the evaporator 14 where the evaporator 14 may change the phase of the working fluid from a liquid and vapor mixture to a vapor in order to gain heat. The vapor may then be moved through the suction line 18 to the compressor 16. The suction line 18 may include at least one sensor including a pressure sensor 20, a temperature sensor 22, a combination sensor or other sensors as known by one of ordinary skill in the art. The information determined by the sensors in the suction line 18 may be sent to a controller which may then control the speed and other characteristics of the working fluid. From the suction line 18, the working fluid may be transferred through the compressor 16 and out to a discharge line 42. The discharge line 42 may be free of sensors or may include a temperature or other sensor. Again, any information gathered by the sensors may be sent to the controller for further control of the working fluid. Next, the working fluid may flow from the discharge line 42 through the condenser 12. The condenser 12 may be constructed and arranged to change the phase of the working fluid from a gas to a liquid. The condenser 12 may include an outlet 52 and the outlet may be operably coupled to the liquid line 46 which then may enter into the evaporator 14 to begin the cycle again. The pressure and temperature in the suction line 18 may be taken at any time prior to the beginning of the circuit, during operation of the circuit or after operation of the circuit as known by one of ordinary skill in the art.
The following description of variants is only illustrative of components, elements, acts, product and methods considered to be within the scope of the invention and are not in any way intended to limit such scope by what is specifically disclosed or not expressly set forth. The components, elements, acts, product and methods as described herein may be combined and rearranged other than as expressly described herein and still are considered to be within the scope of the invention.
Variation 1 may include a refrigeration circuit which may include a condenser operably coupled to an evaporator along with a compressor operably coupled to the evaporator using a suction line, wherein the suction line may include a pressure sensor and a temperature sensor.
Variation 2 may include a refrigeration circuit as set forth in variation 1 further comprising a controller constructed and arranged to disable a clutch during a low charge condition.
Variation 3 may include the refrigeration circuit as set forth in any of variations 1 to 2 wherein the controller includes an algorithm to determine whether the circuit is in a low charge condition.
Variation 4 may include the refrigeration circuit as set forth in any of variations 1 to 3 wherein a temperature sensor may be disposed in the discharge line.
Variation 5 may include the refrigeration circuit as set forth in any of variations 1 to 4 wherein the temperature sensor may be the only sensor disposed in the discharge line.
Variation 6 may include the refrigeration circuit as set forth in any of variations 1 to 5 wherein temperature and pressure may be measured directly in the suction line.
Variation 7 may include the refrigeration circuit as set forth in any of variations 1 to 6 wherein the pressure sensor and the temperature sensor may be a single combination sensor which may be constructed and arranged to directly measure both pressure and temperature in the suction line.
Variation 8 may include a system which may include a condenser operably coupled to an evaporator via a liquid line and expansion valve along with a compressor operably coupled to the evaporator via a suction line, wherein a pressure sensor and a temperature sensor may be disposed in the suction line.
Variation 9 may include the system as set forth in any of variations 1 to 8 further comprising a controller.
Variation 10 may include the system as set forth in any of variations 1 to 9 wherein the controller may be constructed and arranged to use an algorithm to determine a torque of the compressor.
Variation 11 may include the system as set forth in any of variations 1 to 10 wherein the temperature sensor may be disposed in the discharge line.
Variation 12 may include the system as set forth in any of variations 1 to 11 wherein the temperature sensor may be the only sensor disposed in the discharge line.
Variation 13 may include the system as set forth in any of variations 1 to 12 wherein the temperature and pressure may be directly measured in the suction line.
Variation 14 may include the system as set forth in any of variations 1 to 13 wherein the pressure sensor and the temperature sensor may be a single combination sensor constructed and arranged to directly measure both pressure and temperature.
Variation 15 may include a method which may include providing a refrigeration circuit comprising a condenser operably coupled to an evaporator and a compressor operably coupled to the evaporator via a suction line and measuring both a pressure and temperature directly in the suction line.
Variation 16 may include the method as set forth in variation 15 wherein a controller may be constructed and arranged to control flow in the refrigeration circuit.
Variation 17 may include the method as set forth in any variations 15 to 16 further comprising determining a torque of the compressor using the pressure and temperature of the suction line.
Variation 18 may include the method as set forth in any of variations 15 to 17 wherein the pressure sensor and the temperature sensor may be a single combination sensor constructed and arranged to directly measure both pressure and temperature in the suction line.
Variation 19 may include the method as set forth in any of variations 15 to 18 further comprising disabling a clutch when it is determined that the circuit may be in a low charge mode.
Variation 20 may include the method as set forth in any of variations 15 to 19 wherein the condenser and the evaporator may be operably coupled by a liquid line.
The above description of select variations within the scope of the invention is merely illustrative in nature and, thus, variations or variants thereof are not to be regarded as a departure from the spirit and scope of the invention.

Claims

What is claimed is:

1. A refrigeration circuit comprising:

a condenser operably coupled to an evaporator;

a compressor operably coupled to the evaporator using a suction line, wherein the suction line includes a pressure sensor and a temperature sensor.

2. The refrigeration circuit of claim 1, further comprising a controller constructed and arranged to reduce the compressor capacity or disable a clutch during a low charge condition.

3. The refrigeration circuit of claim 1, wherein the controller includes an algorithm to determine whether the circuit is in a low charge condition.

4. The refrigeration circuit of claim 3, wherein a temperature sensor is disposed in the discharge line.

5. The refrigeration circuit of claim 4, wherein the temperature sensor is the only sensor disposed in the discharge line.

6. The refrigeration circuit of claim 1, wherein temperature and pressure are measured directly in the suction line.

7. The refrigeration circuit of claim 1, wherein the pressure sensor and the temperature sensor are a single combination sensor constructed and arranged to directly measure both pressure and temperature in the suction line.

8. A system comprising:

a condenser operably coupled to an evaporator via a liquid line and expansion valve;

a compressor operably coupled to the evaporator via a suction line, wherein a pressure sensor and a temperature sensor are disposed in the suction line.

9. The system of claim 8, further comprising a controller.

10. The system of claim 8, wherein the controller is constructed and arranged to use an algorithm to determine a torque of the compressor.

11. The system of claim 10, wherein a temperature sensor is disposed in the discharge line.

12. The system of claim 8, wherein a temperature sensor is the only sensor disposed in the discharge line.

13. The system of claim 8, wherein temperature and pressure are measured directly in the suction line.

14. The system of claim 8, wherein the pressure sensor and the temperature sensor are a single combination sensor constructed and arranged to directly measure both pressure and temperature.

15. A method comprising:

providing a refrigeration circuit comprising a condenser operably coupled to an evaporator via a liquid line and expansion valve and a compressor operably coupled to the evaporator via a suction line;

measuring both a pressure and temperature directly in the suction line.

16. The method of claim 15, wherein a controller is constructed and arranged to control flow in the refrigeration circuit.

17. The method of claim 16, further comprising determining a torque of the compressor using the pressure and temperature of the suction line.

18. The method of claim 15, wherein the pressure sensor and the temperature sensor are a single combination sensor constructed and arranged to directly measure both pressure and temperature in the suction line.

19. The method of claim 15, further comprising reducing the capacity or disabling a clutch when it is determined that the circuit is in a low charge mode.

20. The method of claim 15, wherein the condenser and the evaporator are operably coupled by the liquid line and the expansion valve.