Constant-speed air conditioner

Abstract

The constant-speed air conditioner comprises a temperature detection unit which is arranged at the top of a compressor shell and used for detecting the sum of the exhaust temperature of a press and the top temperature of the press; when the detected temperature is in an abnormal working temperature interval higher than the normal working temperature interval, the control unit is configured to output a compressor cylinder clamping fault when the temperature fluctuation rate is 1; when the temperature fluctuation rate reaches the upper limit value of the third fluctuation rate threshold value and is smaller than 1, the shut-off fault of the stop valve is output; when the temperature fluctuation ratio is larger than or equal to zero and reaches the lower limit value of a third fluctuation ratio threshold value, the filth blockage fault of the air conditioning system is output; the temperature fluctuation rate is the ratio of the temperature difference to the temperature fluctuation time in the abnormal working temperature interval, and the third fluctuation rate threshold value is calibrated in advance. According to the method, the specific fault of the constant-speed air conditioner in the abnormal working temperature interval can be judged.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and particularly to a constant-speed air conditioner. Background Art

[0002] A constant-speed air conditioner refers to an air-conditioning system in which the rotational speed of the internal compressor motor remains constant, and the temperature is adjusted by controlling the on / off of the compressor. Currently, most constant-speed air conditioners on the market mainly control the indoor temperature by reaching the set temperature and stopping, that is, when the indoor temperature is the same as the set temperature, the air conditioner stops running; when the indoor temperature rises, the air conditioner restarts.

[0003] Due to the advantages of stable operation, diverse applicable environments, low price, high cost performance, etc., constant-speed air conditioners are widely used. For such air conditioners, for cost considerations, the control is very simple, and the parameters that can be detected are few. Generally, three temperature sensors are set: an outdoor temperature detector for detecting the outdoor ambient temperature Ta, a refrigerant state temperature detector for detecting the refrigerant state (generally placed on the system pipeline), and an exhaust temperature detector for detecting the exhaust temperature of the refrigerant discharged by the compressor (generally placed on the exhaust pipe at the compressor discharge port). With few detected parameters, it is difficult to accurately judge the abnormal state of the air conditioner.

[0004] For such air conditioners, generally, a thermal protector is set on the top of the compressor, placed at the top position of the compressor, to detect and protect the compressor from abnormal heating. This thermal protector is generally of the bimetallic type and mainly has two parameters: protection temperature and recovery temperature. When the temperature at the top of the compressor rises and reaches the protection temperature of the thermal protector, the contacts of the bimetallic protector deform, cutting off the power supply of the compressor. After the compressor stops, the temperature at the top of the compressor will gradually decrease. When it reaches the recovery temperature, the metal contacts resume conduction, and the compressor resumes power supply.

[0005] However, in this way of using a thermal protector, when the compressor stops, it stops and alarms for a compressor failure. However, for the alarm signal, it only simply indicates a compressor failure without obtaining the detailed cause of the failure.

[0006] Therefore, how to obtain the specific cause of the failure of a constant-speed air conditioner with fewer detected parameters for a constant-speed air conditioner is a technical problem to be solved at present.

[0007] The above information disclosed in this background art is only used to increase the understanding of the background art of the present application. Therefore, it may include prior art that is not known to those of ordinary skill in the art. Summary of the Invention

[0008] To address the problems pointed out in the background art, the present application provides a constant-speed air conditioner. By introducing the temperature volatility rate and based on the pre-calibrated temperature volatility rate, it determines the specific faults of the constant-speed air conditioner in the abnormal operating temperature range, improving the operating reliability of the air-conditioning unit.

[0009] To achieve the above-mentioned invention objectives, the present invention adopts the following technical solutions: The present application relates to a constant-speed air conditioner, including: A refrigerant circulation circuit that enables the refrigerant to circulate in a circuit composed of a compressor, a condenser, an expansion valve, and an evaporator; A compressor for compressing low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharging it to the condenser; An outdoor heat exchanger and an indoor heat exchanger, where one functions as a condenser and the other functions as an evaporator; A temperature detection unit placed on the top of the compressor housing for detecting the sum of the compressor discharge temperature and the compressor top temperature; A control unit, when the temperature detected by the temperature detection unit is in an abnormal operating temperature range higher than the normal operating temperature range, the control unit is configured to: When the temperature volatility rate reaches 1, output a compressor stuck cylinder fault; When the temperature volatility rate reaches the upper limit value of the third volatility threshold and is less than 1, output a cut-off valve closed fault; When the temperature volatility rate is greater than or equal to zero and reaches the lower limit value of the third volatility threshold, output an air-conditioning system dirt blockage fault; Wherein, the temperature volatility rate is the ratio of the product of the temperature difference, temperature fluctuation, and weight in the abnormal operating temperature range, and the third volatility threshold is pre-calibrated.

[0010] Regarding the constant-speed air conditioner of the present application, considering that the refrigerant flow is beneficial to the compressor heat dissipation, within the abnormal operating temperature range of the compressor, by introducing the temperature volatility rate related to the heat generation of the compressor, it determines the specific faults that cause the large heat of the compressor.

[0011] This constant-speed air conditioner can refine and output the specific faults caused by the large heat generation of the compressor, which helps to analyze the faults of the air-conditioning system.

[0012] In some embodiments of the present application, before judging the fault, the third volatility threshold is pre-calibrated, specifically: With the help of a throttling device arranged on the exhaust pipe of the compressor outlet, under the standard refrigeration condition, by adjusting the opening of the throttling device, calculate the temperature volatility rate, and calibrate the calculated temperature volatility rate as the third volatility threshold.

[0013] The third volatility threshold is calibrated before fault judgment of the air conditioner, which helps to utilize the calibrated volatility threshold to compare the temperature volatility during the actual operation of the constant-speed air conditioner when it is operating normally, so as to realize the judgment of specific faults.

[0014] For example, the opening degree of the throttling device can be adjusted to 5% of the opening degree, that is, the flow rate is 5% of the normal flow rate, and the heat dissipation capacity of the refrigerant flow to the compressor is equivalent to 5% of the original. In this way, the calculated temperature volatility is used as the calibrated third volatility threshold.

[0015] In some embodiments of the present application, the temperature difference is the difference between the protection temperature at final shutdown and the normal operating temperature boundary.

[0016] During calibration, when the opening degree of the throttling device is, for example, 5%, the compressor load is relatively large at this time. When the temperature reaches the protection temperature at final shutdown, record the temperature fluctuation time, and calculate the temperature volatility based on the ratio between the temperature difference and the product of the temperature fluctuation time and the weight.

[0017] In some embodiments of the present application, the present application is used to determine system faults under abnormal operating temperatures. Therefore, the protection temperature at final shutdown and the normal operating temperature boundary are respectively the upper limit value and the lower limit value of the abnormal operating temperature range; When the temperature reaches the protection temperature at final shutdown, the constant-speed air conditioner shuts down; When the temperature reaches the lower limit value of the normal operating temperature boundary, the constant-speed air conditioner operates normally.

[0018] In some embodiments of the present application, the weight is related to the outdoor ambient temperature; According to the outdoor ambient temperature during the operation of the constant-speed air conditioner and the outdoor ambient temperature under the standard refrigeration condition, determine the weight.

[0019] The outdoor ambient temperature will affect the heat dissipation efficiency of the compressor. Therefore, the calculation of the temperature volatility takes the outdoor ambient temperature into account, which improves the reliability of using the temperature volatility to judge faults.

[0020] In some embodiments of the present application, the higher the outdoor ambient temperature, the higher the heat dissipation efficiency. Therefore, when the outdoor ambient temperature during the operation of the constant-speed air conditioner is greater than the outdoor ambient temperature under the standard refrigeration condition, the weight is greater than 1; When the outdoor ambient temperature during the operation of the constant-speed air conditioner is less than the outdoor ambient temperature under the standard refrigeration condition, the weight is greater than zero and less than 1.

[0021] In some embodiments of the present application, when the gas-side cut-off valve on the gas side and the liquid-side cut-off valve on the liquid side are fully closed, they have different effects on the heat dissipation of the compressor. Therefore, according to the calculated different temperature volatility rates, the fully-closed failure of the cut-off valve is refined.

[0022] The fixed-speed air conditioner further includes: A gas-side cut-off valve connected to the gas-side pipeline of the indoor heat exchanger; A liquid-side cut-off valve connected to the liquid-side pipeline of the indoor heat exchanger; When the temperature volatility rate reaches the upper limit value of the third volatility threshold and is less than 1, an output of the fully-closed failure of the cut-off valve is generated. Specifically: When the fixed-speed air conditioner is in the heating mode, if the temperature volatility rate reaches the upper limit value of the first volatility threshold and is less than 1, at least the fully-closed failure of the gas-side cut-off valve is output; When the fixed-speed air conditioner is in the cooling mode, if the temperature volatility rate reaches the lower limit value of the first volatility threshold and the upper limit value of the second volatility threshold, an output of the fully-closed failures of both the gas-side cut-off valve and the liquid-side cut-off valve is generated; When the fixed-speed air conditioner is in the cooling mode, if the temperature volatility rate reaches the lower limit value of the second volatility threshold and the upper limit value of the third volatility threshold, an output of the fully-closed failure of either the gas-side cut-off valve or the liquid-side cut-off valve is generated; When the fixed-speed air conditioner is in the heating mode, if the temperature volatility rate reaches the lower limit value of the second volatility threshold and the upper limit value of the third volatility threshold, an output of the fully-closed failure of the liquid-side cut-off valve is generated; Wherein, the first volatility threshold, the second volatility threshold, and the third volatility threshold gradually decrease.

[0023] In some embodiments of the present application, the fixed-speed air conditioner further includes: A four-way valve for switching the flow path of the refrigerant discharged from the compressor; A silencer disposed on the exhaust pipe between the exhaust port of the compressor and the four-way valve, and the throttling device is disposed on a part of the pipeline between the silencer and the four-way valve or on a part of the pipeline between the exhaust port of the compressor and the silencer.

[0024] In some embodiments of the present application, the fixed-speed air conditioner further includes: A silencer disposed on the pipeline on the side of the gas-side cut-off valve away from the indoor heat exchanger.

[0025] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become clearer. Description of the Drawings

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 It is a principle block diagram of an air conditioner in an embodiment of a constant-speed air conditioner proposed in this application; Figure 2 It is a flowchart for determining weights according to the outdoor ambient temperature in an embodiment of a constant-speed air conditioner proposed in this application; Figure 3 It is the system frame of an embodiment of a constant-speed air conditioner proposed in this application Figure 1 ; Figure 4 It is the system frame of an embodiment of a constant-speed air conditioner proposed in this application Figure 2 ; Figure 5 It is a relationship diagram between the opening degree of a throttling device and the temperature fluctuation rate during calibration in an embodiment of a constant-speed air conditioner proposed in this application; Figure 6 It is a flowchart for fault judgment in an embodiment of a constant-speed air conditioner proposed in this application; Figure 7 It is a flowchart for fault judgment in the heating mode in an embodiment of a constant-speed air conditioner proposed in this application; Figure 8 It is a flowchart for fault judgment in the cooling mode in an embodiment of a constant-speed air conditioner proposed in this application; Figure 9 It is the system frame of an embodiment of a constant-speed air conditioner proposed in this application Figure 3 ; Figure 10 It is the system frame of an embodiment of a constant-speed air conditioner proposed in this application Figure 4 。

[0028] Reference numerals: 10. Compressor; 20. Outdoor heat exchanger; 30. Indoor heat exchanger; 40. Four-way valve; 50. Gas-side stop valve; 60. Liquid-side stop valve; 70. Throttling device; 80. First silencer; 80'. Second silencer; 90. Accumulator. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0030] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0031] The terms "first" and "second" are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, the meaning of "a plurality" is two or more.

[0032] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0033] In the present invention, unless otherwise clearly specified and defined, the fact that the first feature is "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the fact that the first feature is "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the horizontal height of the first feature is higher than that of the second feature. The fact that the first feature is "below", "beneath" and "under" the second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the horizontal height of the first feature is lower than that of the second feature.

[0034] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. This repetition is for the purpose of simplification and clarity, and in itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0035] <Basic working principle of an air conditioner> See Figure 1 , the air conditioner performs a refrigeration cycle of the air conditioner by using a compressor 10, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation to cool or heat an indoor space.

[0036] The low-temperature and low-pressure refrigerant enters the compressor 10, and the compressor 10 compresses the refrigerant gas into a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0037] The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant formed by condensation in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor 10. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant to exchange heat with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0038] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor 10 and the outdoor heat exchanger 20. The indoor unit of the air conditioner includes the indoor heat exchanger 30, and the expansion valve can be provided in the indoor unit or the outdoor unit.

[0039] The indoor heat exchanger 30 and the outdoor heat exchanger 20 serve as condensers or evaporators. When the indoor heat exchanger 30 serves as a condenser, the air conditioner serves as a heater in the heating mode. When the indoor heat exchanger 30 serves as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0040] Air conditioners are divided into fixed-speed air conditioners and variable-speed air conditioners.

[0041] A fixed-speed air conditioner refers to an air-conditioning system in which the rotational speed of the internal compressor motor is constant, and the temperature is adjusted by controlling the on / off of the compressor.

[0042] A variable-speed air conditioner refers to an air-conditioning system that adjusts the temperature by changing the refrigerant circulation volume in the pipeline by adjusting the rotational speed of the compressor motor, thereby changing the cooling capacity.

[0043] Due to its simple structure, a fixed-speed air conditioner generally has three temperature sensors: an outdoor temperature detector for detecting the outdoor ambient temperature Ta, a refrigerant state temperature detector for detecting the refrigerant state, and an exhaust temperature detector for detecting the exhaust temperature Td of the refrigerant discharged from the compressor.

[0044] Among them, the refrigerant state temperature detector is generally placed on the system pipeline, and the exhaust temperature detector is generally placed on the exhaust pipe at the compressor discharge port.

[0045] In this application, the position of the exhaust temperature detector is moved downward and placed on the top of the housing of the compressor 10. The temperature detected here is the sum T of the compressor exhaust temperature Td and the compressor top temperature Tr.

[0046] When the unit is operating normally, the heat generated by the compressor 10 itself is mainly affected by the system load. The heat generated by the compressor 10 itself is mainly concentrated in the middle of the compressor 10, and a small part is transferred to the top of the compressor 10 through its housing.

[0047] During the operation of the air-conditioning system, the heat generated by the compressor 10 will be quickly carried away by the circulating refrigerant, and T is equal to Td. Due to the complex working environment of the air-conditioning system, Td is affected by factors such as the operating mode (such as the cooling mode and the heating mode), the outdoor unit ambient temperature Ta, and the refrigerant volume, and the characteristics shown are quite different.

[0048] Through actual machine tests, it can be obtained that, for example, the normal operating temperature range of T can be determined to be between 40°C and 95°C, and its maximum value is not a fixed value and is greatly affected by the overall machine capacity (compressor displacement). This maximum value is set as the normal operating temperature boundary.

[0049] When T exceeds this operating range, it is considered that the air-conditioning system is in an abnormal operating state. When T is too high, the abnormal high temperature comes from the transfer of the heat generated by the compressor 10 itself and the change of the heat dissipation conditions of the refrigerant system.

[0050] The temperature in the abnormal operating state is called the abnormal operating temperature.

[0051] Among them, in some embodiments of this application, when the T temperature is too high and exceeds the final shutdown protection temperature (such as T2, which is set to 125°C), the air-conditioning system shuts down for protection.

[0052] Therefore, the abnormal operating temperature as described above is 95°C to 125°C.

[0053] This application relates to the fault judgment of a fixed-speed air conditioner at the abnormal operating temperature.

[0054] As described above, the main sources of the high T are the heat transfer from the compressor 10 itself and the change in the heat dissipation condition of the refrigerant system.

[0055] When there is no refrigerant flow or the refrigerant flow rate is small, the heat generated by the compressor 10 cannot be quickly removed. Coupled with a large load, the compressor 10 itself generates a large amount of heat. Therefore, T will be high.

[0056] In order to be able to judge the faults of the air conditioner under abnormal working temperatures, the present application determines the fault conditions of the air conditioning system by introducing the temperature volatility λ related to the temperature T.

[0057] Among them, in some embodiments of the present application, the temperature volatility λ = (T1 - T2) / (k * t).

[0058] Among them, T1 is the protection temperature at the final shutdown, T2 is the normal temperature boundary, k is the weight, and t is the temperature fluctuation time.

[0059] As described above, T1 can be 125°C and T2 can be 95°C.

[0060] k can be a fixed weight.

[0061] Considering that the outdoor ambient temperature also affects the heat dissipation of the compressor 10, k can also be a weight determined according to the outdoor ambient temperature, that is, k is the ambient temperature correction coefficient. Under a fixed outdoor ambient temperature, this k is a fixed value obtained by testing.

[0062] Before making a fault judgment, it is necessary to calibrate the temperature volatility λ first, so as to determine the fault conditions of the air conditioning system for reference.

[0063] Under standard test conditions, the temperature volatility λ is calibrated.

[0064] The outdoor ambient temperature under standard test conditions is the standard ambient temperature. According to the outdoor ambient temperature Ta at the end of the operation of the constant-speed air conditioner and the standard ambient temperature, k is tested and determined.

[0065] See Figure 2 , in some embodiments of the present application, the standard ambient temperature is set to 35°C.

[0066] For example, when Ta > 35°C, k > 1.

[0067] Considering the influence of the outdoor ambient temperature on the temperature volatility λ, when Ta < 35°C, k can be greater than the first weight parameter, k can be greater than 0, k can be greater than 0.2, k can be greater than 0.5, etc. This first weight parameter changes in positive correlation with the outdoor ambient temperature.

[0068] However, since the standard ambient temperature is set to 35°C, when Ta < 35°C, k should be less than 1.

[0069] Within the abnormal operating temperature range, calibrate the temperature volatility λ. According to the standard refrigeration condition, the ambient temperature is 35°C, and the refrigerant is charged with the marked amount.

[0070] The air-conditioning system gets contaminated with impurities or lacks oil, resulting in damage and wear to the mechanical device of the compressor 10 cylinder, and finally the compressor 10 cylinder gets stuck.

[0071] At this time, the compressor 10 cylinder is stuck, the motor is in a locked-rotor state, and the system refrigerant no longer circulates.

[0072] When the compressor 10 is locked-rotor and there is no refrigerant flow for heat dissipation, set the temperature volatility λ to 1 at this time.

[0073] When the temperature volatility λ is 1, the temperature at the top of the compressor 10 all comes from the self-heating of the compressor 10. Because the compressor 10 is in a locked-rotor state, it can be considered the maximum heating state of the compressor 10. At the same time, there is no refrigerant flow for heat dissipation, and the heat dissipation condition is extremely unfavorable.

[0074] Under such abnormal conditions, the temperature at the top of the compressor 10 rises extremely fast and will soon reach the final shutdown protection temperature, which is 125°C.

[0075] See Figure 3 and Figure 4 , in order to determine other faults that cause T to be too high in a fixed-speed air conditioner, this application uses a temporarily added throttling device 70. By changing the opening degree of the throttling device 70, the refrigerant amount entering the system is adjusted, so as to simulate the influence of the refrigerant circulation in the system on the too high T, and thus determine the possible faults.

[0076] Set up the throttling device 70 on the exhaust pipeline of the compressor 10. Control the refrigerant flow rate entering the air-conditioning system through this throttling device 70. Set the opening degree of this throttling device 70 from 0 to 100. An opening degree of 0 means the throttling device 70 is completely closed, and an opening degree of 100 means the throttling device 70 is completely open.

[0077] The air-conditioning system is charged with the standard amount of refrigerant and operates under the standard refrigeration condition, with the outdoor ambient temperature being 35°C.

[0078] Adjust the opening degree of the throttling device 70 to obtain the corresponding relationship between the temperature volatility λ and the opening degree.

[0079] In the initial stage, the opening degree of the throttling device 70 is small, and at this time the temperature volatility λ ≈ 1.

[0080] As the opening degree of the throttling device 70 increases, a small amount of refrigerant in the air-conditioning system begins to flow, which can quickly cool down the compressor 10. The load of the compressor 10 decreases, and its own heat generation also rapidly decreases. The time for the temperature T at the top of the compressor 10 to reach T1 has an exponential relationship with the opening degree of the throttling device 70. At the same time, the temperature fluctuation rate λ has an exponential decreasing trend with the opening degree of the throttling device 70 (that is, the base of the exponential relationship is negative). See Figure 5 .

[0081] That is, the larger the opening degree, the longer the time for the temperature T at the top of the compressor 10 to reach T1, and the smaller the temperature fluctuation rate λ.

[0082] In some embodiments of the present application, when the opening degree of the throttling device 70 is adjusted to 5%, the flow rate at this time is 5% of the normal flow rate, and the refrigerant heat dissipation capacity is only 5% of the original. The load of the compressor 10 is relatively large. After a period of time t1, T reaches 125 °C. At this time, the calculated temperature fluctuation rate λ is calibrated as Figure 5 the third fluctuation rate threshold λ3 in

[0083] The third fluctuation rate threshold can also be a range of fluctuation rates.

[0084] The specific opening degree of the throttling device 70 corresponding to the third fluctuation rate threshold λ3 needs to be tested through multiple experiments.

[0085] When the temperature fluctuation rate λ reaches the upper limit value of the third fluctuation rate threshold and is less than 1, an output cut-off valve closed failure is output.

[0086] See Figure 6 , in some embodiments of the present application, when the temperature fluctuation rate λ is greater than or equal to the third fluctuation rate threshold λ3 and less than 1, an output cut-off valve closed failure is output.

[0087] In some embodiments of the present application, see Figure 3 and Figure 4 , the cut-off valve includes a gas-side cut-off valve 50 and a liquid-side cut-off valve 60.

[0088] The four-way valve 40 is used to switch the flow path of the refrigerant discharged from the compressor 10.

[0089] The gas-side cut-off valve 50 is connected to the gas-side pipeline of the indoor heat exchanger 30, specifically connected to the pipeline between the four-way valve 40 and the indoor heat exchanger 30.

[0090] The liquid-side cut-off valve 60 is connected to the liquid-side pipeline of the indoor heat exchanger 30, specifically connected to the pipeline between the indoor heat exchanger 30 and the outdoor heat exchanger 20.

[0091] Due to the failure of the liquid-side stop valve 60 being closed and the failure of the gas-side stop valve 50 being closed, the impacts on T under different operating modes are different. Therefore, between λ3 and 1, λ1 and λ2 are further divided, where λ1 > λ2 and both are greater than λ3 (see Figure 5 ).

[0092] Since the opening of the throttling device 70 corresponding to λ3 is already relatively small, during calibration, λ1 and λ2 may not be calibrated. After calibrating λ3, λ1 and λ2 can be set according to the relationship among λ1, λ2, and λ3.

[0093] The larger the temperature volatility λ, the more it indicates that the temperature T reaches T1 in a short time, which means that less heat generated by the compressor is carried away by the refrigerant flow in the system.

[0094] Therefore, considering the impact of the refrigerant quantity caused by the failure on the heat dissipation effect of the compressor, the temperature volatility λ can be greater than the first temperature parameter, and the stop valve failure is output, indicating that due to the stop valve failure, the refrigerant quantity cannot circulate normally in the compressor for heat dissipation.

[0095] λ can be greater than λ3, λ can be greater than λ2, and λ can be greater than λ1.

[0096] And since in the most severe case, λ is approximately equal to 1, all the calculated temperature volatility λ values should be less than 1.

[0097] In some embodiments of the present application, when the opening of the throttling device 70 is adjusted to 10%, the flow rate at this time is 10% of the normal flow rate, and the refrigerant heat dissipation capacity is equivalent to 10% of the original. However, due to the normal flow of the refrigerant, the load of the compressor 10 is relatively small. After a relatively long period of time t2 (i.e., t2 > t1), T reaches 125 °C. At this time, the calculated temperature volatility λ is calibrated as Figure 5 a certain value within the range of 0 to λ3 in

[0098] The throttling device 70 can be an expansion valve with adjustable opening.

[0099] After completing the calibration, the throttling device 70 is disassembled. Then, when the constant-speed air conditioner operates in the abnormal working temperature range, the calibrated temperature volatility λ is used for fault determination.

[0100] Due to impurities entering the air-conditioning system, the pipeline is blocked. After this problem occurs, generally, the air-conditioning system will operate normally, but the capacity attenuation is serious.

[0101] When the dirt blockage is serious, it will cause T to appear in the abnormal working temperature range. When the temperature volatility λ is greater than or equal to zero and reaches the lower limit value of the third volatility threshold, the dirt blockage fault of the air-conditioning system is output.

[0102] In some embodiments of the present application, seeFigure 6 When the temperature volatility λ is greater than or equal to 0 and less than the third volatility threshold λ3, a dirty blockage fault of the air conditioning system is output.

[0103] See Figures 6 to 8 When the temperature volatility λ is between λ3 and 1, the cut-off valve fully closed fault can be refined.

[0104] Td is affected by the operating mode (such as the refrigeration mode and the heating mode). Therefore, in some embodiments of the present application, the cut-off valve faults are judged separately according to the refrigeration mode and the heating mode.

[0105] See Figure 3 The solid arrow shows the refrigerant flow direction in the heating mode.

[0106] In some embodiments, the four-way valve 40 is powered on and commutated to connect D and E and connect C and S. The compressor 10 compresses the low-temperature and low-pressure refrigerant into a high-temperature and high-pressure state, and the refrigerant discharged from the compressor 10 passes through the gas-side cut-off valve 50 and the extended pipe through D and E and enters the indoor heat exchanger 30.

[0107] After heat exchange and condensation in the indoor heat exchanger 30 to release heat, it becomes a liquid refrigerant. Subsequently, the refrigerant passes through the throttling device (not shown) on the indoor unit side, the extended pipe and the liquid-side cut-off valve 60, and enters the throttling device to be throttled to a low-temperature and low-pressure gas-liquid two-phase state.

[0108] The two-phase refrigerant enters the outdoor heat exchanger 20 to evaporate and absorb heat, becoming gaseous. The refrigerant coming out of the outdoor heat exchanger 20 enters the accumulator 90 through C and S, and is finally sucked into the compressor 10 for compression to complete the heating cycle.

[0109] See Figure 7 In the heating mode, when calculating that the temperature volatility λ is between λ1 and 1, it is determined that at least the gas-side cut-off valve 50 is fully closed.

[0110] In the heating mode, if the gas-side cut-off valve 50 is fully closed.

[0111] Since the pipeline between the compressor 10 exhaust and the gas-side cut-off valve 50 is very short, after starting to operate, a large amount of refrigerant is compressed in a short time, and the compressor 10 is in a large-load working state. The compressor 10 continuously compresses the refrigerant. After compressing to a certain extent, the compressor 10 is close to stalling, and the motor of the compressor 10 will quickly heat up, and there is no refrigerant flow for heat dissipation. The heat is transferred to the top position of the compressor 10 through the shell of the compressor 10. At this time, the calculated temperature volatility λ should be between λ1 and 1.

[0112] In the heating mode, if both the gas-side cut-off valve 50 and the liquid-side cut-off valve 60 are fully closed.

[0113] In this case, the refrigerant connection between the outdoor unit and the indoor unit is directly interrupted. At this time, the calculated temperature fluctuation rate λ should be between λ1 and 1.

[0114] See Figure 8 , in the cooling mode, when the calculated temperature fluctuation rate λ is between λ2 and λ1, it is determined that both the gas-side cut-off valve 50 and the liquid-side cut-off valve 60 are closed, which is a failure.

[0115] In the cooling mode, if both the gas-side cut-off valve 50 and the liquid-side cut-off valve 60 are closed, the refrigerant connection between the outdoor unit and the indoor unit is directly interrupted. The compressor 10 compresses the refrigerant and discharges it into the outdoor heat exchanger 20. The load of the compressor 10 is large, and the refrigerant amount on the suction side is quickly drained. Without refrigerant for heat dissipation, the temperature of the compressor 10 rises rapidly. At this time, the calculated temperature fluctuation rate λ should be between λ1 and λ2.

[0116] In the cooling mode, when the calculated temperature fluctuation rate λ is between λ3 and λ2, it is determined that either the gas-side cut-off valve 50 is closed or the liquid-side cut-off valve 60 is closed.

[0117] In the cooling mode, if the gas-side cut-off valve 50 is closed.

[0118] The compressor 10 discharges the refrigerant into the outdoor heat exchanger 20 and the indoor heat exchanger 30. At the beginning, the load of the compressor 10 is relatively low, but the refrigerant amount on the suction side is small and the refrigerant cannot return from the indoor side, resulting in a lack of refrigerant in the compressor 10 and an increase in temperature T. At this time, the calculated temperature fluctuation rate should be between λ3 and λ2.

[0119] In the cooling mode, if the liquid-side cut-off valve 60 is closed.

[0120] The refrigerant cannot enter the indoor heat exchanger 30. The compressor 10 is in a vacuum state. The compressor 10 extracts the refrigerant in the indoor unit and compresses it all into the outdoor heat exchanger 20 on the outdoor unit side. After the refrigerant extraction is completed, due to the lack of refrigerant flow for heat dissipation in the compressor 10 itself, the temperature T of the compressor 10 finally rises. At this time, the calculated temperature fluctuation rate should be between λ3 and λ2.

[0121] Return to see Figure 7 , in the heating mode, if the liquid-side cut-off valve 60 is closed.

[0122] The refrigerant cannot enter the outdoor heat exchanger 20. The compressor 10 is in a vacuum state. The compressor 10 extracts the refrigerant in the outdoor unit and compresses it all into the indoor heat exchanger 30 on the indoor unit side. After the refrigerant extraction is completed, due to the lack of refrigerant flow for heat dissipation in the compressor 10 itself, the temperature T of the compressor 10 finally rises. At this time, the calculated temperature fluctuation rate should be between λ3 and λ2.

[0123] In this way, it is possible to determine the failure of the gas-side stop valve 50 and / or the liquid-side stop valve 60, and reliably monitor the failure points of the air-conditioning system in the abnormal operating temperature range.

[0124] The determined failure can be output and a reminder can be given.

[0125] The constant-speed air conditioner involved in this application can refine the determination of the failure of the air-conditioning system when the constant-speed air conditioner operates in the abnormal operating temperature range through the pre-calibrated temperature volatility λ, improve the efficiency of finding failure points, and provide a reference basis for troubleshooting.

[0126] See Figure 9 , a first muffler 80 is provided on the exhaust pipe between the exhaust port of the compressor 10 and the four-way valve 40, which is used to weaken the noise of the refrigerant discharged by the compressor 10 and improve the user experience.

[0127] When the throttling device 70 is set as described above, the throttling device 70 can be set on a part of the pipeline between the first muffler 80 and the four-way valve 40, or the throttling device 70 can also be set on a part of the pipeline between the first muffler 80 and the exhaust port of the compressor 10, based on the ease of disassembling the throttling device 70 from the pipeline.

[0128] See Figure 9 , a second muffler 80' can also be provided on the pipeline on the side of the gas-side stop valve 50 away from the indoor heat exchanger 30 to avoid the noise generated by the gaseous refrigerant.

[0129] In some embodiments, a muffler can also be provided on other parts of the pipeline, which is not limited here.

[0130] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0131] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A constant-speed air conditioner, characterized in that, Comprising: A refrigerant circulation circuit that circulates refrigerant in a circuit composed of a compressor, a condenser, an expansion valve, and an evaporator; A compressor for compressing low-temperature and low-pressure refrigerant gas into high-temperature and high-pressure refrigerant gas and discharging it to the condenser; An outdoor heat exchanger and an indoor heat exchanger, where one functions as a condenser and the other functions as an evaporator; A temperature detection unit disposed on the top of the compressor housing for detecting the sum of the compressor discharge temperature and the compressor top temperature; A control unit, when the temperature detected by the temperature detection unit is in an abnormal operating temperature range higher than the normal operating temperature range, the control unit is configured as: When the temperature volatility reaches 1, output a compressor stuck cylinder fault; When the temperature volatility reaches the upper limit value of the third volatility threshold and is less than 1, output a stop valve closed fault; When the temperature volatility is greater than or equal to zero and reaches the lower limit value of the third volatility threshold, output an air-conditioning system dirt blockage fault; Wherein, the temperature volatility is the ratio of the product of the temperature difference, temperature fluctuation, and weight in the abnormal operating temperature range, and the third volatility threshold is pre-calibrated.

2. The constant-speed air conditioner according to claim 1, wherein Before judging the fault, pre-calibrate the third volatility threshold, specifically: By means of a throttling device provided on the exhaust pipe of the compressor, under standard refrigeration conditions, by adjusting the opening of the throttling device, calculate the temperature volatility, and calibrate the calculated temperature volatility as the third volatility threshold.

3. The constant-speed air conditioner according to claim 2, wherein The temperature difference is the difference between the protection temperature at the final shutdown and the normal operating temperature boundary.

4. The constant-speed air conditioner according to claim 3, characterized in that, The protection temperature at the final shutdown and the normal operating temperature boundary are respectively the upper limit value and the lower limit value of the abnormal operating temperature range; When the temperature reaches the protection temperature at the final shutdown, the constant-speed air conditioner shuts down; When the temperature reaches the lower limit value of the normal operating temperature boundary, the constant-speed air conditioner operates normally.

5. The constant-speed air conditioner according to claim 3, wherein, The weight is related to the outdoor ambient temperature; Determine the weight according to the outdoor ambient temperature during the operation of the constant-speed air conditioner and the outdoor ambient temperature under standard refrigeration conditions.

6. The constant-speed air conditioner according to claim 5, wherein When the outdoor ambient temperature during the operation of the constant-speed air conditioner is greater than the outdoor ambient temperature under standard refrigeration conditions, the weight is greater than 1; When the outdoor ambient temperature during the operation of the constant-speed air conditioner is less than the outdoor ambient temperature under standard refrigeration conditions, the weight is greater than zero and less than 1.

7. The constant-speed air conditioner according to claim 1, wherein The constant-speed air conditioner further includes: A gas-side stop valve connected to the gas-side pipeline of the indoor heat exchanger; A liquid-side stop valve connected to the liquid-side pipeline of the indoor heat exchanger; When the temperature volatility reaches the upper limit value of the third volatility threshold and is less than 1, output a stop valve closed fault, specifically: When the constant-speed air conditioner is in the heating mode, if the temperature volatility reaches the upper limit value of the first volatility threshold and is less than 1, output at least the gas-side stop valve closed fault; When the constant-speed air conditioner is in the cooling mode, if the temperature volatility reaches the lower limit value of the first volatility threshold and the upper limit value of the second volatility threshold, output the fault that both the gas-side stop valve and the liquid-side stop valve are closed. When the constant-speed air conditioner is in the cooling mode, if the temperature volatility reaches the lower limit value of the second volatility threshold and the upper limit value of the third volatility threshold, output the fault that the gas-side stop valve or the liquid-side stop valve is closed. When the constant-speed air conditioner is in the heating mode, if the temperature volatility reaches the lower limit value of the second volatility threshold and the upper limit value of the third volatility threshold, output the fault that the liquid-side stop valve is closed. Among them, the first volatility threshold, the second volatility threshold and the third volatility threshold gradually decrease.

8. The constant-speed air conditioner according to claim 2, characterized in that, The constant-speed air conditioner further includes: A four-way valve for switching the flow path of the refrigerant discharged from the compressor; A muffler provided on the exhaust pipe between the exhaust port of the compressor and the four-way valve, and the throttling device is provided on a part of the pipe between the muffler and the four-way valve or on a part of the pipe between the exhaust port of the compressor and the muffler.

9. The constant-speed air conditioner according to claim 7, wherein The constant-speed air conditioner further includes: A muffler provided on the pipe on the side of the gas-side stop valve away from the indoor heat exchanger.

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