A control method for implementing a refrigerant leakage warning function

Abstract

The present invention relates to the technical field of refrigerant leakage detection of temperature control equipment, and discloses a control method for realizing a refrigerant leakage alarm function, comprising the following steps: after the air conditioner is powered on and the cooling or dehumidification mode is turned on, the controller enters the refrigerant leakage judgment program, and at τ1 minutes after the compressor is turned on, the measured values ​​AVEstart1 and AVEstart2 of the return air temperature T1 in the cabinet and the coil temperature T2 in the cabinet are recorded; from K to K+τ2 minutes after the compressor is turned on, the measured values ​​AVGT1 and AVGT2 of T1 and T2 are calculated; by comparing the relationship between AVEstart1, AVEstart2, AVGT1, AVGT2 and the preset temperature difference and other conditions, it is judged whether the refrigerant is leaking. In the normal refrigeration system control logic, the present invention uses the temperature sensor provided by the equipment, writes a protection program and applies it to temperature control equipment products such as cabinet air conditioners, and reduces the manufacturing cost and development and testing cost compared with the control scheme of the traditional pressure sensor, is simpler and more universal, and ensures the timeliness and accuracy of the refrigerant leakage judgment.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigerant leakage detection of temperature control equipment, and specifically provides a control method for realizing the refrigerant leakage warning function. Background Art

[0002] Before leaving the factory, air conditioners are pre-filled with a certain amount of refrigerant. However, due to non-standard production and installation or cracks caused by pipeline vibration during operation, refrigerant leakage may occur in the system. Depending on the size of the crack, the refrigerant leakage duration varies, and in some cases, it may last for a long time. Refrigerant leakage in air conditioners will cause the exhaust temperature to rise and the refrigeration effect to decrease, which has a great impact on the system operation. When the system lacks refrigerant, the exhaust pressure will not rise significantly, so the exhaust pressure will not trigger protection during the leakage process. And the exhaust high-temperature protection is usually in a lag state due to the action of the protector. Even if the compressor stops due to the action of the protector, once the exhaust temperature decreases, it will restart again, falling into a repeated cycle of protection - start. This frequent start will keep the lubricating oil at a high temperature for a long time. As the exhaust temperature gradually rises, it may cause the compressor refrigerating oil to coke, thus jamming the compressor. Therefore, other protection measures need to be found.

[0003] The conventional method for diagnosing refrigerant leakage in air conditioners is to judge by adding pressure sensors to the refrigeration system. For example, the literature "Detecting Refrigerant Leakage with Pressure Sensors" mentions adding high and low pressure sensors to the refrigeration system to monitor the operating pressure parameters of the refrigeration system, so as to judge whether there is refrigerant leakage; the literature "Diagnosis and Prediction of Refrigerant Leakage" uses the changes in system flow and pressure parameters caused by refrigerant leakage to establish a model for comparison and diagnose the refrigerant leakage fault of the system. The method of judging refrigerant leakage by pressure change not only increases the manufacturing cost of air conditioners, but also the difference in environmental temperature between the north and the south will have a certain impact on the change of system pressure, making it more complicated to judge the refrigerant leakage situation. A large amount of experimental data is required to establish a more accurate model, resulting in an increase in test cost. Therefore, a new control method for realizing the refrigerant leakage warning function is proposed. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] The present invention provides a new control method for realizing the refrigerant leakage warning function, which solves the problems of increasing the manufacturing cost and development and test cost of air conditioners by the ordinary method of judging refrigerant leakage.

[0006] (2) Technical Solutions

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A control method for realizing the refrigerant leakage warning function, comprising the following steps:

[0009] S0: Power on the air conditioner, turn on the refrigeration or dehumidification mode, detect the current operating state of the air conditioner. When all components of the air conditioner are operating normally, the controller enters the refrigerant leakage determination program;

[0010] S1: Set the internal counter of the air conditioner to 0, that is, X = 0;

[0011] S2: After the protection duration, at the moment of the first preset duration τ1 minutes after the compressor is turned on, record the measured values AVEstart1 and AVEstart2 of the return air temperature T1 inside the cabinet and the coil temperature T2 inside the cabinet measured by the temperature sensor; AVEstart1 and AVEstart2 can be instantaneous values. Preferably, AVEstart1 and AVEstart2 can also be the average value or filtered average value within a period of time (such as 6 seconds);

[0012] S3: When the running time K of the compressor after it is turned on is within K minutes to (K + the second preset duration τ2) minutes, calculate the measured values AVGT1 and AVGT2 of T1 and T2 every third preset duration τ3 seconds. The value of K in S3 is based on the value of the internal loop counter X. When X = 0, K = K1 minutes; when X = 1, K = K2 minutes; when X = 2, K = K3 minutes;... when X = M - 1, K = KM minutes; K1 > K2 > K3 >... > KM > τ1, K1 to KM are the fourth series of preset durations. Preferably, K1 to KM follow an arithmetic progression relationship. AVGT1 and AVGT2 can be instantaneous values. Preferably, AVGT1 and AVGT2 can also be the average value within a period of time;

[0013] S4: At the moment when the running time of the compressor after it is turned on is (K + τ2) minutes, determine whether a "suspected refrigerant leakage fault" has occurred; if a "suspected refrigerant leakage fault" has occurred, enter step S5, otherwise enter step S6;

[0014] S5: If a "suspected refrigerant leakage fault" has occurred, then display the refrigerant leakage warning and the compressor does not start;

[0015] S6: The whole machine operates normally.

[0016] Further, the determination in S4 includes the following situations:

[0017] S401: Condition A: The first preset temperature t1 ≤ the return air temperature outside the cabinet T4 measured by the temperature sensor ≤ the second preset temperature t2; Condition B: After K minutes, the difference between the measured value AVGT1 of the return air temperature T1 inside the cabinet and the measured value AVGT2 of the coil temperature T2 inside the cabinet ≤ the first preset temperature difference Δt1; Condition C: The absolute value of the difference between the measured value AVEstart2 of the coil temperature T2 inside the cabinet when the compressor is turned on and the measured value AVGT2 of the coil temperature T2 inside the cabinet after K minutes < the second preset temperature difference Δt2; Condition D: The difference between the measured value AVEstart1 of the return air temperature T1 inside the cabinet when the compressor is turned on and the measured value AVGT1 of the return air temperature T1 inside the cabinet after K minutes < the third preset temperature difference Δt3. When in multiple comparisons within K to (K + τ2) minutes, if there is a non - satisfied item among Conditions A, B, C, and D, it is judged as "normal refrigerant", and go to step S6; when Conditions A, B, C, and D are simultaneously satisfied in multiple comparisons within K to (K + τ2) minutes, go to step S5.

[0018] In the above - mentioned technical solution, S4 may further include S402: Condition E: The exhaust temperature TP > the third preset temperature t3 and the total machine power < the first preset power p1; Condition F: The compressor frequency > the first preset frequency F1 (such as 48 Hz) and the total machine power < p1; Condition G: Exhaust temperature frequency limit occurs or the exhaust temperature TP > t3 and the compressor frequency < the second preset frequency F2 (such as 50 Hz). When in multiple comparisons within K to (K + τ2) minutes, if any one of Conditions E, F, and G is satisfied, it is judged as "suspected refrigerant leakage fault", and go to step S5; if Conditions E, F, and G are not satisfied, go to step S6.

[0019] S401 and S402 can be used as the determination steps of S4 separately. Preferably, if both S401 and S402 are judged as "suspected refrigerant leakage fault", go to step S5; otherwise, go to step S6.

[0020] S4 includes a judgment module, and the judgment module is connected to a storage module and a control module.

[0021] As a further solution of the present invention, S4 further includes S404: Before judging as "suspected refrigerant leakage fault" and entering step S5, the internal counter counts, X = X + 1.

[0022] On the basis of the above scheme, S5 includes S501: if a "suspected refrigerant leakage fault" occurs, determine the size of the count X. If X is less than the cumulative number of "suspected refrigerant leakage faults" M, enter step S502: the compressor is shut down for the fifth preset time τ5 minutes. After τ5 minutes, enter step S2 for re-judgment; otherwise, enter step S503: if a "suspected refrigerant leakage fault" occurs M times in a row, a refrigerant leakage alarm is displayed and the compressor does not start.

[0023] As a further solution of the present invention, S4 may also include S403: before S401 determines that the "suspected refrigerant leakage fault" enters S5, an additional judgment condition H is added: internal fan speed limit, if the current set internal fan speed in> minimum wind speed MINin+(1 / 5 of the maximum wind speed MAXin), the operating wind speed NEXTin after restriction is changed to the current set internal fan speed in-(1 / 5 of the maximum wind speed MAXin); if the current set internal fan speed in≤ minimum wind speed MINin+(1 / 5 of the maximum wind speed MAXin), the operating wind speed NEXTin after restriction is changed to the current set internal fan speed in-(1 / 5 of the maximum wind speed MAXin); if the current set internal fan speed in≤ minimum wind speed MINin+(1 / 5 of the maximum wind speed MAXin), the operating wind speed NEXTin after restriction is changed to the current set internal fan speed 5), the restricted running wind speed NEXTin is changed to the minimum wind speed MINin, and the running time is the sixth preset time length τ6 minutes. After the wind speed limit of τ6 minutes, the timing is reset to τ2 minutes. Within τ2 minutes, the measured values ​​AVGT1 and AVGT2 of T1 and T2 are calculated every τ3 seconds to re-judge whether a refrigerant leakage fault has occurred. At this time, multiple comparisons only need to judge conditions A, B, C, and D. If all four conditions are met at the same time, it is judged that a "suspected refrigerant leakage fault" has occurred, and the process goes to step S5; otherwise, the internal fan resumes normal operation and the process goes to step S6.

[0024] On the basis of the above scheme, further, when the whole machine in S6 operates normally, S601: when T1 reaches the set temperature and the compressor stops normally, the timing starts from the restart of the compressor, and every seventh preset time τ7 minutes returns to step S3 for judgment again, and S602: before returning to step S3, the internal counter is reset, X=0, so as to continuously cycle the judgment and play the role of real-time monitoring of whether the refrigerant is leaking.

[0025] (III) Beneficial effects

[0026] The present invention provides a new control method for realizing the refrigerant leakage alarm function. The method utilizes the temperature sensor provided by the temperature control device. Compared with the control scheme of the traditional pressure sensor, the method reduces the manufacturing cost and the development and testing cost. The method is simpler and more universal, and ensures the timeliness and accuracy of the refrigerant leakage judgment. The method can shut down the machine in time when the refrigerant leaks, thereby protecting the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of the logic flow structure of a control method for realizing a refrigerant leakage alarm function proposed by the present invention;

[0028] Figure 2 Schematic diagram of the details of step S3 of a control method for implementing a refrigerant leakage warning function proposed by the present invention;

[0029] Figure 3 Schematic diagram of the details of step S401 of a control method for implementing a refrigerant leakage warning function proposed by the present invention;

[0030] Figure 4 Schematic diagram of the details of step S402 of a control method for implementing a refrigerant leakage warning function proposed by the present invention.

[0031] Figure 5 Schematic diagram of the details of step S403 of a control method for implementing a refrigerant leakage warning function proposed by the present invention. Detailed implementation manner

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] Refer to Figures 1-5 , a control method for implementing a refrigerant leakage warning function, includes the following steps:

[0034] S0: Power on the air conditioner, turn on the cooling or dehumidification mode, detect the current operating state of the air conditioner. When all components of the air conditioner are operating normally, the controller enters the refrigerant leakage determination program;

[0035] S1: Set the internal counter of the air conditioner to 0, that is, X = 0;

[0036] S2: After the protection duration, at the 2-minute moment after the compressor is turned on, record the 6-second average values AVEstart1 and AVEstart2 of the return air temperature T1 in the cabinet and the coil temperature T2 in the cabinet;

[0037] S3: When the compressor is turned on for a time within K minutes to K + 2 minutes, calculate the average values AVGT1 and AVGT2 of T1 and T2 every 6 seconds for 20 times. The value of K in S3 is based on the value of the internal loop counter X. When X = 0, K = 20 minutes; when X = 1, K = 15 minutes; when X = 2, K = 10 minutes;

[0038] S401: At the moment when the compressor start-up time reaches K + 2 minutes, determine whether there is a refrigerant leakage fault. The determination in S401 includes the following situations: Condition A: t1 ≤ the return air temperature outside the cabinet T4 ≤ t2; Condition B: After K minutes, the difference between the 6-second average value AVGT1 of the return air temperature inside the cabinet and the 6-second average value AVGT2 of the coil temperature inside the cabinet ≤ Δt1; Condition C: The absolute value of the difference between the 6-second average value AVEstart2 of the coil temperature inside the cabinet at the start of the compressor and the 6-second average value AVGT2 of the coil temperature inside the cabinet after K minutes < Δt2; Condition D: The difference between the 6-second average value AVEstart1 of the return air temperature inside the cabinet at the start of the compressor and the 6-second average value AVGT1 of the return air temperature inside the cabinet after K minutes < Δt3. When there is a non-satisfied item among Conditions A, B, C, and D in 20 comparisons, it is determined as "normal refrigerant", and go to step S601; when Conditions A, B, C, and D are simultaneously satisfied in 20 comparisons, go to step S402;

[0039] S402: Determine whether there is a refrigerant leakage fault through Conditions E, F, and G. Condition E: The exhaust temperature TP > t3 and the total machine power < p1; Condition F: The compressor frequency > 48 Hz and the total machine power < p1; Condition G: Exhaust temperature frequency limit occurs or the exhaust temperature TP > t3 and the compressor frequency < 50 Hz. When any one of Conditions E, F, and G is satisfied, it is determined as "suspected refrigerant leakage fault", and go to step S404; when Conditions E, F, and G are not satisfied, go to step S403;

[0040] S404: Determine as "suspected refrigerant leakage fault", and the internal counter counts, X = X + 1;

[0041] S501: Determine the count size. If X < 3, go to step S502; otherwise, go to step S503;

[0042] S502: Determine as "suspected refrigerant leakage fault", the compressor stops for 3 minutes. After 3 minutes, go to step S2 for re-determination;

[0043] S403: Determine condition H: the internal fan speed limit. If the currently set internal fan speed in > the minimum wind speed MINin + (1 / 5 of the maximum wind speed MAXin), then the restricted operating wind speed NEXTin is changed to the currently set internal fan speed in - (1 / 5 of the maximum wind speed MAXin); if the currently set internal fan speed in ≤ the minimum wind speed MINin + (1 / 5 of the maximum wind speed MAXin), then the restricted operating wind speed NEXTin is changed to the minimum wind speed MINin, and the operation time is 5 minutes. After 5 minutes of wind speed restriction, the timing is restarted for 2 minutes. Within 2 minutes, the average values AVGT1 and AVGT2 of T1 and T2 are calculated every 6 s, and it is re-determined whether a refrigerant leakage fault has occurred. At this time, for 20 comparisons, only conditions A, B, C, and D need to be judged. If all 4 conditions are met simultaneously, it is judged that a "suspected refrigerant leakage fault" has occurred, and step S404 is entered; otherwise, the internal fan resumes normal operation, and step S601 is entered.

[0044] S601: The whole machine operates normally. After T1 reaches the set temperature, starting from when the compressor restarts, it is timed, and every 10 minutes, it returns to step S3 through step S602.

[0045] S602: Clear the internal counter, X = 0, and enter step S3 for re-judgment.

[0046] S503: If a "suspected refrigerant leakage fault" shutdown occurs continuously 3 times, a refrigerant leakage alarm is displayed, and the compressor does not start.

[0047] In particular, the meanings represented by the above letters are: T1: the return air temperature inside the cabinet; T2: the coil temperature inside the cabinet; T4: the return air temperature outside the cabinet; t1, t2, t3, Δt1, Δt2, Δt3, p1 are all parameter values, and the specific parameter values are adjusted according to the test results of different models.

[0048] In the description of this article, it should be noted that relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device.

[0049] Expressions involving specific data and mathematical symbols such as "2 minutes", "6s average value", "K + 2", "6s", "20 times", "X = 0, K = 20 minutes; when X = 1, K = 15 minutes; when X = 2, K = 10 minutes", "48Hz", "50Hz", "3 minutes", "1 / 5", "5 minutes", "3 consecutive times", "≤", "<", ">" in the text are only used to help understand the method and its core idea of the present invention, rather than intended to limit the present invention."

[0050] The expression "internal counter" in the text is only to better illustrate the variation relationship between the number of cycles and the running time in the embodiments, rather than a necessary condition for limiting the present invention."

[0051] All the conditions, logical relationships, and loop judgments in the text are only some preferred embodiments of the present invention, rather than all the embodiments. The above embodiments are only for illustrative purposes of the present invention, rather than limitations on the present invention."

[0052] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various deletions, changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents."

Claims

1. A control method for realizing the refrigerant leakage warning function, characterized in that, It includes the following steps: S0: Power on the air conditioner, turn on the cooling or dehumidification mode, detect the current operating state of the air conditioner. When all components of the air conditioner are operating normally, the controller enters the refrigerant leakage determination program; S1: Set the internal counter of the air conditioner to 0, i.e., X = 0; S2: After the protection duration, at the moment of the first preset duration τ1 minutes after the compressor is turned on, record the measured values AVEstart1 and AVEstart2 of the return air temperature T1 inside the cabinet and the coil temperature T2 inside the cabinet; S3: When the running time K of the compressor is within K minutes to K + the second preset duration τ2 minutes, calculate the measured values AVGT1 and AVGT2 of T1 and T2 every τ3 seconds. The value of K is based on the value of the internal loop counter X. When X = 0, K = K1 minutes; When X = 1, K = K2 minutes; When X = 2, K = K3 minutes;... When X = M - 1, K = KM minutes; K1 > K2 > K3 >... > KM > τ1, and K1 to KM are the fourth series of preset durations; S4: Determine whether a "suspected refrigerant leakage fault" has occurred; if a "suspected refrigerant leakage fault" has occurred, go to step S5, otherwise go to step S6. At the moment of K + τ2 minutes after the compressor is turned on, determine whether a refrigerant leakage fault has occurred. The determination includes the following situations: S401: Condition A: The first preset temperature t1 ≤ the return air temperature T4 outside the cabinet ≤ the second preset temperature t2; Condition B: After K minutes, the difference between the measured value AVGT1 of the return air temperature T1 inside the cabinet and the measured value AVGT2 of the coil temperature T2 inside the cabinet ≤ the first preset temperature difference Δt1; Condition C: The absolute value of the difference between the measured value AVEstart2 of the coil temperature T2 inside the cabinet when the compressor is turned on and the measured value AVGT2 of the coil temperature T2 inside the cabinet after K minutes < the second preset temperature difference Δt2; Condition D: The difference between the measured value AVEstart1 of the return air temperature T1 inside the cabinet when the compressor is turned on and the measured value AVGT1 of the return air temperature T1 inside the cabinet after K minutes < the third preset temperature difference Δt3. When there are non - satisfied items among conditions A, B, C, and D in multiple comparisons within K to K + τ2 minutes, it is determined that the "refrigerant is normal", and go to step S6; when multiple comparisons within K to K + τ2 minutes all satisfy conditions A, B, C, and D at the same time, go to step S5; It also includes S402: Condition E: The exhaust temperature TP > the third preset temperature t3 and the total machine power < the first preset power p1; Condition F: The compressor frequency > the first preset frequency F1 and the total machine power < p1; Condition G: Exhaust temperature frequency limit occurs or the exhaust temperature TP > t3 and the compressor frequency < the second preset frequency F2. If any one of conditions E, F, and G is satisfied, it is determined that a "suspected refrigerant leakage fault" has occurred, and go to step S5; when conditions E, F, and G are all not satisfied, go to step S6; S5: If a "suspected refrigerant leakage fault" has occurred, display a refrigerant leakage alarm, and the compressor does not start; S6: The whole machine operates normally.

2. The control method for realizing the refrigerant leakage warning function according to claim 1, characterized in that, The S401 and the S402 are respectively used as the determination steps of S4 alone; if both the S401 and the S402 are judged as "suspected refrigerant leakage fault", then go to step S5; otherwise, go to step S6. The S4 includes a judgment module, and the judgment module is connected to a storage module and a control module.

3. The control method for realizing the refrigerant leakage warning function according to claim 1, characterized in that, The S4 includes S404: When it is judged as "suspected refrigerant leakage fault" and before entering step S5, the internal counter counts, and X = X + 1.

4. The control method for realizing the refrigerant leakage warning function according to claim 3, wherein, The S5 includes S501: If a "suspected refrigerant leakage fault" occurs, judge the magnitude of the count X. If X < the cumulative number M of "suspected refrigerant leakage faults", then go to step S502; otherwise, go to step S503.

5. The control method for implementing the refrigerant leakage warning function according to claim 4, characterized in that, The S5 includes S502: The compressor stops for the fifth preset duration τ5 minutes. After τ5 minutes, enter step S2 for re-judgment. The S5 includes S503: If a "suspected refrigerant leakage fault" occurs continuously for M times, then display a refrigerant leakage alarm and the compressor does not start.

6. The control method for realizing the refrigerant leakage warning function according to claim 4, characterized in that, The S4 includes S403: Before the S401 determines a "suspected refrigerant leakage fault" and enters S5, an additional judgment condition H is added: restrict the internal fan speed. If the current set internal fan speed > the minimum wind speed + (1 / 5 of the maximum wind speed), then the operating wind speed is changed to the current set internal fan speed - (1 / 5 of the maximum wind speed); if the current set internal fan speed ≤ the minimum wind speed + (1 / 5 of the maximum wind speed), then the operating wind speed is changed to the minimum wind speed. The operating time is the sixth preset duration τ6 minutes. After the wind speed is restricted for τ6 minutes, the timer is restarted for τ2 minutes. During τ2 minutes, the measured values AVGT1 and AVGT2 of T1 and T2 are calculated every τ3 seconds, and it is re-judged whether a refrigerant leakage fault has occurred. At this time, only the judgment conditions A, B, C, and D need to be compared multiple times. If all 4 conditions are met simultaneously, then it is judged that a "suspected refrigerant leakage fault" has occurred and go to step S5; otherwise, the internal fan resumes normal operation and goes to step S6.

7. The control method for realizing the refrigerant leakage warning function according to claim 6, characterized in that, The S6 includes S601: When the whole machine runs normally, after T1 reaches the set temperature and the compressor stops normally, start timing from the restart of the compressor, and return to step S3 for re-judgment every seventh preset duration τ7 minutes; S602: Clear the internal counter before returning to step S3, and X = 0.

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